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Sample records for single-pulse transcranial magnetic

  1. A Study of Cortical Excitability, Central Motor Conduction, and Cortical Inhibition Using Single Pulse Transcranial Magnetic Stimulation in Patients with Early Frontotemporal and Alzheimer's Dementia.

    Science.gov (United States)

    Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor; Nagaraju, B C; Philip, Mariamma

    2016-01-01

    Degenerative cortical dementias affect several million people worldwide. Early diagnosis and categorization are essential for initiating appropriate pharmacological and nonpharmacological treatment so that deterioration can be postponed, and disability adjusted life years can be saved both for the patient and for the caregiver. Therefore, an early, simple, noninvasive biomarker will serve as a boon. Patients who satisfied probable Alzheimer's disease (AD) or frontotemporal dementia (FTD) using international consensus criteria for FTD and National Institute of Neurological Disorders and Stroke-AD and Related Disorders Association criteria for AD were evaluated using single pulse transcranial magnetic stimulation with figure of eight coil and motor evoked potential from right first dorsal interossei. Resting threshold (MT), central motor conduction time (CMCT), and silent period (SP) were evaluated. Resting MT and SP are reduced in patients with Alzheimer's disease whereas CMCT is prolonged in patients with FTD and SP is in the lower limit of normal in both conditions. The patterns of central motor conduction and MT are distinctly different in patients with early Alzheimer's disease (AD) and FTD.

  2. Sequential roles of primary somatosensory cortex and posterior parietal cortex in tactile-visual cross-modal working memory: a single-pulse transcranial magnetic stimulation (spTMS) study.

    Science.gov (United States)

    Ku, Yixuan; Zhao, Di; Hao, Ning; Hu, Yi; Bodner, Mark; Zhou, Yong-Di

    2015-01-01

    Both monkey neurophysiological and human EEG studies have shown that association cortices, as well as primary sensory cortical areas, play an essential role in sequential neural processes underlying cross-modal working memory. The present study aims to further examine causal and sequential roles of the primary sensory cortex and association cortex in cross-modal working memory. Individual MRI-based single-pulse transcranial magnetic stimulation (spTMS) was applied to bilateral primary somatosensory cortices (SI) and the contralateral posterior parietal cortex (PPC), while participants were performing a tactile-visual cross-modal delayed matching-to-sample task. Time points of spTMS were 300 ms, 600 ms, 900 ms after the onset of the tactile sample stimulus in the task. The accuracy of task performance and reaction time were significantly impaired when spTMS was applied to the contralateral SI at 300 ms. Significant impairment on performance accuracy was also observed when the contralateral PPC was stimulated at 600 ms. SI and PPC play sequential and distinct roles in neural processes of cross-modal associations and working memory. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. [Transcranial magnetic stimulation].

    Science.gov (United States)

    Tormos, J M; Catalá, M D; Pascual-Leone, A

    Transcranial magnetic stimulation (TMS) permits stimulation of the cerebral cortex in humans without requiring open access to the brain and is one of the newest tools available in neuroscience. There are two main types of application: single-pulse TMS and repetitive TMS. The magnetic stimulator is composed of a series of capacitors that store the voltage necessary to generate a stimulus of the sufficient intensity of generate an electric field in the stimulation coil. The safety of TMS is supported by the considerable experience derived from studies involving electrical stimulation of the cortex in animals and humans, and also specific studies on the safety of TMS in humans. In this article we review historical and technical aspects of TMS, describe its adverse effects and how to avoid them, summarize the applications of TMS in the investigation of different cerebral functions, and discuss the possibility of using TMS for the treatment of neuropsychiatric disorders.

  4. Transcranial magnetic stimulation in schizophrenia.

    Science.gov (United States)

    Zaman, Rashid; Thind, Dilraj; Kocmur, Marga

    2008-11-01

    Transcranial magnetic stimulation (TMS) is a non-invasive and painless way of stimulating the neural tissue (cerebral cortex, spinal roots, and cranial and peripheral nerves). The first attempts at stimulating the neural tissue date back to 1896 by d'Arsonval; however, it was successfully carried out by Barker and colleagues in Sheffield, UK, in 1985. It soon became a useful tool in neuroscience for neurophysiologists and neurologists and psychiatrists. The original single-pulse TMS, largely used as an investigative tool, was further refined and developed in the early 1990s into what is known as repetitive TMS (rTMS), having a frequency range of 1-60 Hz. The stimulation by both TMS and rTMS of various cortical regions displayed alteration of movement, mood, and behavior, leading researchers to investigate a number of psychiatric and neuropsychiatric disorders, as well as to explore its therapeutic potential. There is now a large amount of literature on the use of TMS/rTMS in depression; however, its use in schizophrenia, both as an investigative and certainly as a therapeutic tool is relatively recent with a limited but increasing number of publications. In this article, we will outline the principles of TMS/rTMS and critically review their use in schizophrenia both as investigative and potential therapeutic tools.

  5. Transcranial magnetic simulation in the treatment of migraine

    OpenAIRE

    Lipton, Richard B.; Pearlman, Starr H.

    2010-01-01

    Transcranial magnetic stimulation (TMS) is a diagnostic and therapeutic modality that is being developed as both an acute and preventive treatment for migraine. TMS delivers a fluctuating magnetic field from the scalp surface to induce current in the subjacent cortex. Magnetic pulses are delivered one at a time in single-pulse TMS (sTMS) or as a train of pulses in repetitive TMS (rTMS). For most of its 30-year history, TMS has been delivered in clinical and research settings using large table...

  6. Transcranial Magnetic Stimulation in Children

    OpenAIRE

    Garvey, Marjorie A.; Mall, Volker

    2008-01-01

    Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding ef...

  7. [Fundamentals and Clinical Applications of Transcranial Magnetic Stimulation in Neuropsychiatry].

    Science.gov (United States)

    Malavera, Mayra; Silva, Federico; García, Ronald; Rueda, Ligia; Carrillo, Sandra

    2014-03-01

    Transcranial Magnetic Stimulation (TMS) is a non-invasive method for stimulation of brain that is based on the ability of a generated magnetic field to penetrate skull and brain meninges, inducing an electric current in the brain tissues that produces neuronal depolarization. TMS can be applied as single pulse of stimulation, pairs of stimuli separated by variable intervals to the same or different brain areas, or as trains of repetitive stimuli at various frequencies. Its mechanism of action is currently unknown. Repetitive TMS can modify the excitability of the cerebral cortex, and has been postulated as a diagnostic and therapeutic tool in the area of neuropsychiatry. The aim of this article is to review the knowledge of the TMS as regards its basic principles, pathophysiological mechanism, and its usefulness in clinical practice. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  8. Transcranial static magnetic field stimulation of the human motor cortex

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    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-01-01

    Abstract The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

  9. A practical guide to diagnostic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Groppa, S; Oliviero, A; Eisen, A

    2012-01-01

    Transcranial magnetic stimulation (TMS) is an established neurophysiological tool to examine the integrity of the fast-conducting corticomotor pathways in a wide range of diseases associated with motor dysfunction. This includes but is not limited to patients with multiple sclerosis, amyotrophic...... lateral sclerosis, stroke, movement disorders, disorders affecting the spinal cord, facial and other cranial nerves. These guidelines cover practical aspects of TMS in a clinical setting. We first discuss the technical and physiological aspects of TMS that are relevant for the diagnostic use of TMS. We...... then lay out the general principles that apply to a standardized clinical examination of the fast-conducting corticomotor pathways with single-pulse TMS. This is followed by a detailed description of how to examine corticomotor conduction to the hand, leg, trunk and facial muscles in patients. Additional...

  10. Transcranial magnetic stimulation in children.

    Science.gov (United States)

    Garvey, Marjorie A; Mall, Volker

    2008-05-01

    Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding effective interventions for these disorders. We review the literature pertaining to the use of TMS in pediatrics. Most TMS-evoked parameters show age-related changes in typically developing children and some of these are abnormal in a number of childhood-onset neurological disorders. Although no TMS-evoked parameters are diagnostic for any disorder, changes in certain parameters appear to reflect disease burden or may provide a measure of treatment-related improvement. Furthermore, TMS may be especially useful when combined with other neurophysiologic modalities (e.g. fMRI). However, much work remains to be done to determine if TMS-evoked parameters can be used as valid and reliable biomarkers for disease burden, the natural history of neurological injury and repair, and the efficacy of pharmacological and rehabilitation interventions.

  11. Action-blindsight in healthy subjects after transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Kristiansen, Lasse; Rowe, James B.

    2008-01-01

    Clinical cases of blindsight have shown that visually guided movements can be accomplished without conscious visual perception. Here, we show that blindsight can be induced in healthy subjects by using transcranial magnetic stimulation over the visual cortex. Transcranial magnetic stimulation...

  12. Transcranial magnetic simulation in the treatment of migraine.

    Science.gov (United States)

    Lipton, Richard B; Pearlman, Starr H

    2010-04-01

    Transcranial magnetic stimulation (TMS) is a diagnostic and therapeutic modality that is being developed as both an acute and preventive treatment for migraine. TMS delivers a fluctuating magnetic field from the scalp surface to induce current in the subjacent cortex. Magnetic pulses are delivered one at a time in single-pulse TMS (sTMS) or as a train of pulses in repetitive TMS (rTMS). For most of its 30-year history, TMS has been delivered in clinical and research settings using large tabletop devices. Based on the theory that sTMS may disrupt cortical spreading depression, sTMS has been studied and shown to be effective as an acute treatment for migraine with aura. Subsequent work in animal models confirms that sTMS disrupts cortical spreading depression. To make outpatient self-treatment possible, a portable device has been developed for acute treatment of migraine with aura. Based on the theory that rTMS alters brain excitability and neurotransmitter activity, rTMS has been studied as a preventive migraine treatment. A small body of evidence suggests that rTMS may have a role, but further studies are needed. In this review, we summarize the data on TMS as a treatment of migraine, and we suggest directions for future research. Copyright 2010 The American Society for Experimental NeuroTherapeutics, Inc. Published by Elsevier Inc. All rights reserved.

  13. Transcranial magnetic stimulation and the human brain

    Science.gov (United States)

    Hallett, Mark

    2000-07-01

    Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.

  14. The role of pulse shape in motor cortex transcranial magnetic stimulation using full-sine stimuli

    DEFF Research Database (Denmark)

    Delvendahl, Igor; Gattinger, Norbert; Berger, Thomas

    2014-01-01

    A full-sine (biphasic) pulse waveform is most commonly used for repetitive transcranial magnetic stimulation (TMS), but little is known about how variations in duration or amplitude of distinct pulse segments influence the effectiveness of a single TMS pulse to elicit a corticomotor response. Using...... a novel TMS device, we systematically varied the configuration of full-sine pulses to assess the impact of configuration changes on resting motor threshold (RMT) as measure of stimulation effectiveness with single-pulse TMS of the non-dominant motor hand area (M1). In young healthy volunteers, we (i...

  15. Transcranial magnetic stimulation (TMS) in stroke: Ready for clinical practice?

    Science.gov (United States)

    Smith, Marie-Claire; Stinear, Cathy M

    2016-09-01

    The use of transcranial magnetic stimulation (TMS) in stroke research has increased dramatically over the last decade with two emerging and potentially useful functions identified. Firstly, the use of single pulse TMS as a tool for predicting recovery of motor function after stroke, and secondly, the use of repetitive TMS (rTMS) as a treatment adjunct aimed at modifying the excitability of the motor cortex in preparation for rehabilitation. This review discusses recent advances in the use of TMS in both prediction and treatment after stroke. Prediction of recovery after stroke is a complex process and the use of TMS alone is not sufficient to provide accurate prediction for an individual after stroke. However, when applied in conjunction with other tools such as clinical assessment and MRI, accuracy of prediction using TMS is increased. rTMS temporarily modulates cortical excitability after stroke. Very few rTMS studies are completed in the acute or sub-acute stages after stroke and the translation of altered cortical excitability into gains in motor function are modest, with little evidence of long term effects. Although gains have been made in both of these areas, further investigation is needed before these techniques can be applied in routine clinical care. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Dosimetry of typical transcranial magnetic stimulation devices

    Science.gov (United States)

    Lu, Mai; Ueno, Shoogo

    2010-05-01

    The therapeutic staff using transcranial magnetic stimulation (TMS) devices could be exposed to magnetic pulses. In this paper, dependence of induced currents in real human man model on different coil shapes, distance between the coil and man model as well as the rotation of the coil in space have been investigated by employing impedance method. It was found that the figure-of-eight coil has less leakage magnetic field and low current density induced in the body compared with the round coil. The TMS power supply cables play an important role in the induced current density in human body. The induced current density in TMS operator decreased as the coil rotates from parallel position to perpendicular position. Our present study shows that TMS operator should stand at least 110 cm apart from the coil.

  17. Transcranial Magnetic Stimulation and Aphasia Rehabilitation

    Science.gov (United States)

    Naeser, Margaret A.; Martin, Paula I; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Bhashir, Shahid; Pascual-Leone, Alvaro

    2013-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has been reported to improve naming in chronic stroke patients with nonfluent aphasia since 2005. In Part 1, we review the rationale for applying slow, 1 Hz, rTMS to the undamaged right hemisphere in chronic nonfluent aphasia patients following a left hemisphere stroke; and present a TMS protocol used with these patients that is associated with long-term, improved naming post- TMS. In Part, 2 we present results from a case study with chronic nonfluent aphasia where TMS treatments were followed immediately by speech therapy (constraint-induced language therapy). In Part 3, some possible mechanisms associated with improvement following a series of TMS treatments in stroke patients with aphasia are discussed. PMID:22202188

  18. Field modeling for transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Thielscher, Axel; Antunes, Andre; Saturnino, Guilherme B

    2015-01-01

    ) improving the usability of the tools for field calculation to the level that they can be easily used by non-experts. We then introduce a new version of our pipeline for field calculations (www.simnibs.org) that substantially simplifies setting up and running TMS and tDCS simulations based on Finite......Electric field calculations based on numerical methods and increasingly realistic head models are more and more used in research on Transcranial Magnetic Stimulation (TMS). However, they are still far from being established as standard tools for the planning and analysis in practical applications...... of TMS. Here, we start by delineating three main challenges that need to be addressed to unravel their full potential. This comprises (i) identifying and dealing with the model uncertainties, (ii) establishing a clear link between the induced fields and the physiological stimulation effects, and (iii...

  19. Transcranial magnetic stimulation techniques in clinical investigation.

    Science.gov (United States)

    Currà, A; Modugno, N; Inghilleri, M; Manfredi, M; Hallett, M; Berardelli, A

    2002-12-24

    Transcranial magnetic stimulation (TMS) is a technique that can activate cortical motor areas and the corticospinal tract without causing the subject discomfort. Since TMS was introduced, numerous applications of the technique have been developed for the evaluation of neurologic diseases. Standard TMS applications (central motor conduction time, threshold and amplitude of motor evoked potentials) allow the evaluation of motor conduction in the CNS. Conduction studies provide specific information in neurologic conditions characterized by clinical and subclinical upper motor neuron involvement. In addition, they have proved useful in monitoring motor abnormalities and the recovery of motor function. TMS also gives information on the pathophysiology of the processes underlying the various clinical conditions. More complex TMS applications (paired-pulse stimulation, silent period, ipsilateral silent period, input-output curve, and evaluation of central fatigue) allow investigation into the mechanisms of diseases causing changes in the excitability of cortical motor areas. These techniques are also useful in monitoring the effects of neurotrophic drugs on cortical activity. TMS applications have an important place among the investigative tools to study patients with motor disorders.

  20. Repetitive transcranial magnetic stimulation and drug addiction.

    Science.gov (United States)

    Barr, Mera S; Farzan, Faranak; Wing, Victoria C; George, Tony P; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2011-10-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that is now being tested for its ability to treat addiction. This review discusses current research approaches and results of studies which measured the therapeutic use of rTMS to treat tobacco, alcohol and illicit drug addiction. The research in this area is limited and therefore all studies evaluating the therapeutic use of rTMS in tobacco, alcohol or illicit drug addiction were retained including case studies through NCBI PubMed ( http://www.ncbi.nlm.nih.gov ) and manual searches. A total of eight studies were identified that examined the ability of rTMS to treat tobacco, alcohol and cocaine addiction. The results of this review indicate that rTMS is effective in reducing the level of cravings for smoking, alcohol, and cocaine when applied at high frequencies to the dorsolateral prefrontal cortex (DLPFC). Furthermore, these studies suggest that repeated sessions of high frequency rTMS over the DLPFC may be most effective in reducing the level of smoking and alcohol consumption. Although work in this area is limited, this review indicates that rTMS is a promising modality for treating drug addiction.

  1. Repetitive transcranial magnetic stimulation in psychiatry

    Directory of Open Access Journals (Sweden)

    Biswa Ranjan Mishra

    2011-01-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a non-invasive and relatively painless tool that has been used to study various cognitive functions as well as to understand the brain-behavior relationship in normal individuals as well as in those with various neuropsychiatric disorders. It has also been used as a therapeutic tool in various neuropsychiatric disorders because of its ability to specifically modulate distinct brain areas. Studies have shown that repeated stimulation at low frequency produces long-lasting inhibition, which is called as long-term depression, whereas repeated high-frequency stimulation can produce excitation through long-term potentiation. This paper reviews the current status of rTMS as an investigative and therapeutic modality in various neuropsychiatric disorders. It has been used to study the cortical and subcortical functions, neural plasticity and brain mapping in normal individuals and in various neuropsychiatric disorders. rTMS has been most promising in the treatment of depression, with an overall milder adverse effect profile compared with electroconvulsive therapy. In other neuropsychiatric disorders such as schizophrenia, mania, epilepsy and substance abuse, it has been found to be useful, although further studies are required to establish therapeutic efficacy. It appears to be ineffective in the treatment of obsessive compulsive disorder. There is a paucity of studies of efficacy and safety of rTMS in pediatric and geriatric population. Although it appears safe, further research is required to optimize its efficacy and reduce the side-effects. Magnetic seizure therapy, which involves producing seizures akin to electroconvulsive therapy, appears to be of comparable efficacy in the treatment of depression with less cognitive adverse effects.

  2. Transcranial magnetic stimulation intensities in cognitive paradigms.

    Directory of Open Access Journals (Sweden)

    Jakob A Kaminski

    Full Text Available BACKGROUND: Transcranial magnetic stimulation (TMS has become an important experimental tool for exploring the brain's functional anatomy. As TMS interferes with neural activity, the hypothetical function of the stimulated area can thus be tested. One unresolved methodological issue in TMS experiments is the question of how to adequately calibrate stimulation intensities. The motor threshold (MT is often taken as a reference for individually adapted stimulation intensities in TMS experiments, even if they do not involve the motor system. The aim of the present study was to evaluate whether it is reasonable to adjust stimulation intensities in each subject to the individual MT if prefrontal regions are stimulated prior to the performance of a cognitive paradigm. METHODS AND FINDINGS: Repetitive TMS (rTMS was applied prior to a working memory task, either at the 'fixed' intensity of 40% maximum stimulator output (MSO, or individually adapted at 90% of the subject's MT. Stimulation was applied to a target region in the left posterior middle frontal gyrus (pMFG, as indicated by a functional magnetic resonance imaging (fMRI localizer acquired beforehand, or to a control site (vertex. Results show that MT predicted the effect size after stimulating subjects with the fixed intensity (i.e., subjects with a low MT showed a greater behavioral effect. Nevertheless, the individual adaptation of intensities did not lead to stable effects. CONCLUSION: Therefore, we suggest assessing MT and account for it as a measure for general cortical TMS susceptibility, even if TMS is applied outside the motor domain.

  3. Cerebral ischemia: magnetic resonance angiography and transcranial Doppler evaluation.

    Science.gov (United States)

    D'Aprile, P; Federico, F; Medicamento, N; Conte, C; Carella, A

    1994-02-01

    We examined 21 patients with ischemic cerebrovascular disease using magnetic resonance angiography and transcranial Doppler. In 17 patients (81%), the results obtained by the two methods were concordant. In our opinion, the associated use of transcranial Doppler and magnetic resonance angiography provides an accurate diagnostic evaluation of ischemic stroke patients, not only allowing the site of possible steno-occlusive disease of large and medium cerebral vessels to be identified, but also offering the possibility of obtaining dynamic information concerning the direction of blood flow in the presence of compensatory circulations at the level of Willis' circle.

  4. A real electro-magnetic placebo (REMP) device for sham transcranial magnetic stimulation (TMS).

    Science.gov (United States)

    Rossi, Simone; Ferro, Marisa; Cincotta, Massimo; Ulivelli, Monica; Bartalini, Sabina; Miniussi, Carlo; Giovannelli, Fabio; Passero, Stefano

    2007-03-01

    There is growing interest in neuropsychiatry for repetitive transcranial magnetic stimulation (rTMS) as a neuromodulatory treatment. However, there are limitations in interpreting rTMS effects as a real consequence of physiological brain changes or as placebo-mediated unspecific effects, which may be particularly strong in psychiatric patients. This is due to the fact that existing sham rTMS procedures are less than optimal. A new placebo tool is introduced here, called real electro-magnetic placebo (REMP) device, which can simulate the scalp sensation induced by the real TMS, while leaving both the visual impact and acoustic sensation of real TMS unaltered. Physical, neurophysiological and behavioural variables of monophasic and biphasic single-pulse TMS and biphasic 1Hz and 20Hz rTMS procedures (at different intensities) were tested in subjects who were expert or naïve of TMS. Results of the real TMS were compared with those induced by the REMP device and with two other currently used sham procedures, namely the commercially available Magstim sham coil and tilting the real coil by 90 degrees . The REMP device, besides producing scalp sensations similar to the real TMS, attenuated the TMS-induced electric field (as measured by a dipole probe) to a biologically inactive level. Behaviourally, neither expert nor naïve TMS subjects identified the "coil at 90 degrees " or the "Magstim sham coil" as a real TMS intervention, whilst naïve subjects were significantly more likely to identify the REMP-attenuated TMS as real. The "goodness of sham" of the REMP device is demonstrated by physical, neurophysiological, and behavioural results. Such placebo TMS is superior to the available sham procedures when applied on subjects naïve to TMS, as in case of patients undergoing a clinical rTMS trial.

  5. Computational electromagnetic methods for transcranial magnetic stimulation

    Science.gov (United States)

    Gomez, Luis J.

    Transcranial magnetic stimulation (TMS) is a noninvasive technique used both as a research tool for cognitive neuroscience and as a FDA approved treatment for depression. During TMS, coils positioned near the scalp generate electric fields and activate targeted brain regions. In this thesis, several computational electromagnetics methods that improve the analysis, design, and uncertainty quantification of TMS systems were developed. Analysis: A new fast direct technique for solving the large and sparse linear system of equations (LSEs) arising from the finite difference (FD) discretization of Maxwell's quasi-static equations was developed. Following a factorization step, the solver permits computation of TMS fields inside realistic brain models in seconds, allowing for patient-specific real-time usage during TMS. The solver is an alternative to iterative methods for solving FD LSEs, often requiring run-times of minutes. A new integral equation (IE) method for analyzing TMS fields was developed. The human head is highly-heterogeneous and characterized by high-relative permittivities (107). IE techniques for analyzing electromagnetic interactions with such media suffer from high-contrast and low-frequency breakdowns. The novel high-permittivity and low-frequency stable internally combined volume-surface IE method developed. The method not only applies to the analysis of high-permittivity objects, but it is also the first IE tool that is stable when analyzing highly-inhomogeneous negative permittivity plasmas. Design: TMS applications call for electric fields to be sharply focused on regions that lie deep inside the brain. Unfortunately, fields generated by present-day Figure-8 coils stimulate relatively large regions near the brain surface. An optimization method for designing single feed TMS coil-arrays capable of producing more localized and deeper stimulation was developed. Results show that the coil-arrays stimulate 2.4 cm into the head while stimulating 3

  6. Study of single pulsed-field magnetization of Gd-Ba-Cu-O bulk high-temperature superconductor with a split type of armature coil for rotating machinery

    International Nuclear Information System (INIS)

    Morita, E; Matsuzaki, H; Kimura, Y; Ohtani, I; Ogata, H; Izumi, M; Nonaka, Y; Murakami, M; Ida, T; Sugimoto, H; Miki, M; Kitano, M

    2006-01-01

    We employed a Gd-bulk HTS as rotating field magnet poles aiming for a smaller and lighter axial-gap-type motor. The bulk was inserted in the split-type armature pulsed copper coils and cooled down to 77 K under zero field. Employing the bulk magnet to HTS rotating machinery, the number of pulsed field magnetizations should be reduced for practical use. Thereby, a single pulsed current was applied to the pulsed copper coils to magnetize the bulk. The trapped field distribution and transient flux behaviour strongly depend on the radial dimension of the armature coil with a vortex-type winding. On decreasing the diameter of the pulsed copper armature coil, the distribution of the trapped flux density on the surface of the bulk becomes close to a conical shape. In contrast to the use of a solenoid, the application of vortex-type armature coils to magnetization of Gd-bulk HTS shows a quick intervention of the external magnetic flux into the centre of the bulk. The magnetization to the bulk HTS of the vortex-type copper coils with an optimum radius is useful and may be an effective technique for applied bulk HTS for rotating machines such as motors and/or generators

  7. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Lundbye-Jensen, Jesper; Grey, Michael James

    2010-01-01

    Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb movement...... and its associated somatosensory feedback. Afferent and efferent neural signalling was abolished in the arm with ischemic nerve block, and in the leg with spinal nerve block. Movement sensation was assessed following trains of high-frequency repetitive transcranial magnetic stimulation applied over...... primary motor cortex, dorsal premotor cortex, and a control area (posterior parietal cortex). Magnetic stimulation over primary motor cortex and dorsal premotor cortex produced a movement sensation that was significantly greater than stimulation over the control region. Movement sensation after dorsal...

  8. Transcranial magnetic stimulation-induced global propagation of transient phase resetting associated with directional information flow

    Directory of Open Access Journals (Sweden)

    Masahiro eKawasaki

    2014-03-01

    Full Text Available Electroencephalogram (EEG phase synchronization analyses can reveal large-scale communication between distant brain areas. However, it is not possible to identify the directional information flow between distant areas using conventional phase synchronization analyses. In the present study, we applied transcranial magnetic stimulation (TMS to the occipital area in subjects who were resting with their eyes closed, and analyzed the spatial propagation of transient TMS-induced phase resetting by using the transfer entropy (TE, to quantify the causal and directional flow of information. The time-frequency EEG analysis indicated that the theta (5 Hz phase locking factor (PLF reached its highest value at the distant area (the motor area in this study, with a time lag that followed the peak of the transient PLF enhancements of the TMS-targeted area at the TMS onset. PPI (phase-preservation index analyses demonstrated significant phase resetting at the TMS-targeted area and distant area. Moreover, the TE from the TMS-targeted area to the distant area increased clearly during the delay that followed TMS onset. Interestingly, the time lags were almost coincident between the PLF and TE results (152 vs. 165 ms, which provides strong evidence that the emergence of the delayed PLF reflects the causal information flow. Such tendencies were observed only in the higher-intensity TMS condition, and not in the lower-intensity or sham TMS conditions. Thus, TMS may manipulate large-scale causal relationships between brain areas in an intensity-dependent manner. We demonstrated that single-pulse TMS modulated global phase dynamics and directional information flow among synchronized brain networks. Therefore, our results suggest that single-pulse TMS can manipulate both incoming and outgoing information in the TMS-targeted area associated with functional changes.

  9. Transcranial magnetic stimulation (TMS) in Attention Deficit Hyperactivity Disorder (ADHD).

    Science.gov (United States)

    Zaman, Rashid

    2015-09-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder, which affects children as well as adults and leads to significant impairment in educational, social and occupational functioning and has associated personal and societal costs. Whilst there are effective medications (mostly stimulants) as well as some psychobehavioural treatments that help alleviate symptoms of ADHD, there is still need to improve our understanding of its neurobiology as well as explore other treatment options. Transcranial Magnetic Stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS) are safe and non-invasive investigative and therapeutic tools respectively. In this short article, I will explore their potential for improving our understanding of the neurobiology of ADHD as well consider its as a possible treatment option.

  10. Effects of Navigated Repetitive Transcranial Magnetic Stimulation After Stroke.

    Science.gov (United States)

    Chervyakov, Alexander V; Poydasheva, Alexandra G; Lyukmanov, Roman H; Suponeva, Natalia A; Chernikova, Ludmila A; Piradov, Michael A; Ustinova, Ksenia I

    2018-03-01

    The purpose of this study was to test the effects of navigated repetitive transcranial magnetic stimulation, delivered in different modes, on motor impairments and functional limitations after stroke. The study sample included 42 patients (58.5 ± 10.7 years; 26 males) who experienced a single unilateral stroke (1-12 months previously) in the area of the middle cerebral artery. Patients completed a course of conventional rehabilitation, together with 10 sessions of navigated repetitive transcranial magnetic stimulation or sham stimulation. Stimulation was scheduled five times a week over two consecutive weeks in an inpatient clinical setting. Patients were randomly assigned to one of four groups and received sham stimulation (n = 10), low-frequency (1-Hz) stimulation of the nonaffected hemisphere (n = 11), high-frequency (10-Hz) stimulation of the affected hemisphere (n = 13), or sequential combination of low- and high-frequency stimulations (n = 8). Participants were evaluated before and after stimulation with clinical tests, including the arm and hand section of the Fugl-Meyer Assessment Scale, modified Ashworth Scale of Muscle Spasticity, and Barthel Index of Activities of Daily Living. Participants in the three groups receiving navigated repetitive transcranial magnetic stimulation showed improvements in arm and hand functions on the Fugl-Meyer Stroke Assessment Scale. Ashworth Scale of Muscle Spasticity and Barthel Index scores were significantly reduced in groups receiving low- or high-frequency stimulation alone. Including navigated repetitive transcranial magnetic stimulation in a conventional rehabilitation program positively influenced motor and functional recovery in study participants, demonstrating the clinical potential of the method. The results of this study will be used for designing a large-scale clinical trial.

  11. Effect of Parkinson's Disease in Transcranial Magnetic Stimulation Treatment

    Science.gov (United States)

    Syeda, Farheen; Magsood, Hamzah; Lee, Erik; El-Gendy, Ahmed; Jiles, David; Hadimani, Ravi

    Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

  12. Transcranial magnetic stimulation in patients with early cortical dementia: A pilot study

    Directory of Open Access Journals (Sweden)

    Thomas Gregor Issac

    2013-01-01

    Full Text Available Context: The diagnostic accuracy of the currently available tools carries poor sensitivity resulting in significant delay in specific diagnosis of cortical dementias. Considering the properties of default mode networking of the brain it is highly probable that specific changes may be seen in frontotemporal dementias (FTDs and Alzheimer′s disease sufficiently early. Aim: The aim of this study is to look for changes in Transcranial Magnetic Stimulation (TMS in cortical dementia. Materials and Methods: Evaluated with a single pulse TMS with the figure of eight coil and recorded from right first dorsal interossei (FDI. Resting Motor Threshold (RMT was estimated on the opposite motor cortex (T1. Second site of stimulation was cervical spine at C7-T2. Central motor conduction time (CMCT is equal toT1-T2.Silent Period (SP identified by applying TMS pulse to contracting FDI. Conclusions: RMT was reduced in seven out of eight Alzheimer′s dementias. CMCT was in the upper limit of normal in both patients with FTD. The most consistent observation was that SP was reduced and there were escape discharges noticed during the SP suggesting increased cortical excitability and decreased cortical inhibition. This suggests probable early asymptomatic changes in the gamma-aminobutyric acid (GABA nergic and cholinergic system is taking place. This if confirmed may give some insight into early diagnosis and therapeutic role of GABA agonists in these disorders.

  13. Lifting the veil on the dynamics of neuronal activities evoked by transcranial magnetic stimulation

    Science.gov (United States)

    Li, Bingshuo; Virtanen, Juha P; Oeltermann, Axel; Schwarz, Cornelius; Giese, Martin A; Ziemann, Ulf

    2017-01-01

    Transcranial magnetic stimulation (TMS) is a widely used non-invasive tool to study and modulate human brain functions. However, TMS-evoked activity of individual neurons has remained largely inaccessible due to the large TMS-induced electromagnetic fields. Here, we present a general method providing direct in vivo electrophysiological access to TMS-evoked neuronal activity 0.8–1 ms after TMS onset. We translated human single-pulse TMS to rodents and unveiled time-grained evoked activities of motor cortex layer V neurons that show high-frequency spiking within the first 6 ms depending on TMS-induced current orientation and a multiphasic spike-rhythm alternating between excitation and inhibition in the 6–300 ms epoch, all of which can be linked to various human TMS responses recorded at the level of spinal cord and muscles. The advance here facilitates a new level of insight into the TMS-brain interaction that is vital for developing this non-invasive tool to purposefully explore and effectively treat the human brain. PMID:29165241

  14. Transcranial magnetic stimulation in patients with early cortical dementia: A pilot study.

    Science.gov (United States)

    Issac, Thomas Gregor; Chandra, S R; Nagaraju, B C

    2013-10-01

    The diagnostic accuracy of the currently available tools carries poor sensitivity resulting in significant delay in specific diagnosis of cortical dementias. Considering the properties of default mode networking of the brain it is highly probable that specific changes may be seen in frontotemporal dementias (FTDs) and Alzheimer's disease sufficiently early. The aim of this study is to look for changes in Transcranial Magnetic Stimulation (TMS) in cortical dementia. Evaluated with a single pulse TMS with the figure of eight coil and recorded from right first dorsal interossei (FDI). Resting Motor Threshold (RMT) was estimated on the opposite motor cortex (T1). Second site of stimulation was cervical spine at C7-T2. Central motor conduction time (CMCT) is equal toT1-T2. Silent Period (SP) identified by applying TMS pulse to contracting FDI. RMT was reduced in seven out of eight Alzheimer's dementias. CMCT was in the upper limit of normal in both patients with FTD. The most consistent observation was that SP was reduced and there were escape discharges noticed during the SP suggesting increased cortical excitability and decreased cortical inhibition. This suggests probable early asymptomatic changes in the gamma-aminobutyric acid (GABA) nergic and cholinergic system is taking place. This if confirmed may give some insight into early diagnosis and therapeutic role of GABA agonists in these disorders.

  15. The role of transcranial magnetic stimulation in evaluation of motor cortex excitability in Rett syndrome.

    Science.gov (United States)

    Krajnc, Natalija; Zidar, Janez

    2016-07-01

    Rett syndrome (RTT) is a frequent neurodevelopmental disorder confirmed by clinical criteria and supported by the methyl-CpG-binding protein 2 gene (MECP2) mutation. A short central motor conduction time (CMCT) was reported in transcranial magnetic stimulation (TMS) studies performed in RTT. This was attributed to hyperexcitability of the motor cortex and/or spinal motor neurons, but was not studied further. We performed TMS in RTT to evaluate motor cortex excitability by determining the cortical motor threshold (CMT) and motor cortex inhibition by the cortical silent period (CSP) besides measuring CMCT. Single-pulse TMS was performed in 17 Rett patients, diagnosed by clinical criteria and MECP2 mutation testing, and the same number of healthy controls. The outcome measures were compared between RTT groups with different antiepileptic drugs (AED) and those with and without the MECP2 mutation. CMCT was shorter, but we found elevated CMT and shorter CSP, which suggests decreased excitatory and inhibitory motor cortical function. The outcome was independent of AED and the presence or absence of the MECP2 mutation. Decreased excitatory and inhibitory motor cortical function could explain the short CMCT, with higher stimulus intensities needed to excite pyramidal neurons. Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  16. Laterality of motor cortical function measured by transcranial magnetic stimulation threshold tracking.

    Science.gov (United States)

    Shibuya, Kazumoto; Park, Susanna B; Howells, James; Huynh, William; Noto, Yu-Ichi; Shahrizaila, Nortina; Matamala, José M; Vucic, Steve; Kiernan, Matthew C

    2017-03-01

    Threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS) examines cortical function and is useful for diagnosis of motor neuron disorders. Differences in cortical function have been identified between dominant and non-dominant limbs using constant stimulus methods, but they remain unclear, potentially due to methodological differences. In this study we aimed to clarify differences in cortical function between dominant and non-dominant limbs using TTTMS. Single-pulse TMS, TTTMS, and nerve conduction studies were performed in 25 healthy, right-handed participants by recording from the abductor pollicis brevis muscle. There were no side-to-side differences observed in resting motor threshold, motor evoked potential (MEP) amplitude, MEP latency, central motor conduction time, cortical silent period, short-interval intracortical inhibition and facilitation, compound muscle action potential (CMAP) amplitude, CMAP latency, F-wave latency, or neurophysiological index. These findings suggest that, when using TTTMS, there are no differences in cortical function between dominant and non-dominant hemispheres. Muscle Nerve 55: 424-427, 2017. © 2016 Wiley Periodicals, Inc.

  17. Transcranial magnetic stimulation over human secondary somatosensory cortex disrupts perception of pain intensity.

    Science.gov (United States)

    Lockwood, Patricia L; Iannetti, Gian Domenico; Haggard, Patrick

    2013-09-01

    Pain is a complex sensory experience resulting from the activity of a network of brain regions. However, the functional contribution of individual regions in this network remains poorly understood. We delivered single-pulse transcranial magnetic stimulation (TMS) to the contralateral primary somatosensory cortex (S1), secondary somatosensory cortex (S2) and vertex (control site) 120 msec after selective stimulation of nociceptive afferents using neodymium:yttrium-aluminium-perovskite (Nd:YAP) laser pulses causing painful sensations. Participants were required to judge either the intensity (medium/high) or the spatial location (proximal/distal) of the stimulus in a two-alternative forced choice paradigm. When TMS pulses were delivered over S2, participants' ability to judge pain intensity was disrupted, as compared to S1 and vertex (control) stimulation. Signal-detection analysis demonstrated a loss of sensitivity to stimulation intensity, rather than a shift in perceived pain level or response bias. We did not find any effect of TMS on the ability to localise nociceptive stimuli on the skin. The novel finding that TMS over S2 can disrupt perception of pain intensity suggests a causal role for S2 in encoding of pain intensity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Global perception depends on coherent work of bilateral visual cortices: transcranial magnetic stimulation (TMS) studies.

    Science.gov (United States)

    Zhang, Xin; Han, ShiHui

    2007-08-01

    Previous research suggests that the right and left hemispheres dominate global and local perception of hierarchical patterns, respectively. The current work examined whether global perception of hierarchical stimuli requires coherent work of bilateral visual cortices using transcranial magnetic stimulation (TMS). Subjects discriminated global or local properties of compound letters in Experiment 1. Reaction times were recorded when single-pulse real TMS or sham TMS was delivered over the left or right visual cortex. While a global precedence effect (i.e., faster responses to global than local targets and stronger global-to-local interference than the reverse) was observed, TMS decreased global-to-local interference whereas increased local-to-global interference. Experiment 2 ruled out the possibility that the effects observed in Experiment 1 resulted from perceptual learning. Experiment 3 used compound shapes and observed TMS effect similar to that in Experiment 1. Moreover, TMS also slowed global RTs whereas speeded up local RTs in Experiment 3. Finally, the TMS effects observed in Experiments 1 and 3 did not differ between the conditions when TMS was applied over the left and right hemispheres. The results support a coherence hypothesis that global perception of compound stimuli depends upon the coherent work of bilateral visual cortices.

  19. Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

    Science.gov (United States)

    Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey; Catmur, Caroline

    2014-08-01

    The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  20. Assessing the Effect of Early Visual Cortex Transcranial Magnetic Stimulation on Working Memory Consolidation.

    Science.gov (United States)

    van Lamsweerde, Amanda E; Johnson, Jeffrey S

    2017-07-01

    Maintaining visual working memory (VWM) representations recruits a network of brain regions, including the frontal, posterior parietal, and occipital cortices; however, it is unclear to what extent the occipital cortex is engaged in VWM after sensory encoding is completed. Noninvasive brain stimulation data show that stimulation of this region can affect working memory (WM) during the early consolidation time period, but it remains unclear whether it does so by influencing the number of items that are stored or their precision. In this study, we investigated whether single-pulse transcranial magnetic stimulation (spTMS) to the occipital cortex during VWM consolidation affects the quantity or quality of VWM representations. In three experiments, we disrupted VWM consolidation with either a visual mask or spTMS to retinotopic early visual cortex. We found robust masking effects on the quantity of VWM representations up to 200 msec poststimulus offset and smaller, more variable effects on WM quality. Similarly, spTMS decreased the quantity of VWM representations, but only when it was applied immediately following stimulus offset. Like visual masks, spTMS also produced small and variable effects on WM precision. The disruptive effects of both masks and TMS were greatly reduced or entirely absent within 200 msec of stimulus offset. However, there was a reduction in swap rate across all time intervals, which may indicate a sustained role of the early visual cortex in maintaining spatial information.

  1. Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation

    Science.gov (United States)

    Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey

    2014-01-01

    The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. PMID:23709352

  2. Lifting the veil on the dynamics of neuronal activities evoked by transcranial magnetic stimulation.

    Science.gov (United States)

    Li, Bingshuo; Virtanen, Juha P; Oeltermann, Axel; Schwarz, Cornelius; Giese, Martin A; Ziemann, Ulf; Benali, Alia

    2017-11-22

    Transcranial magnetic stimulation (TMS) is a widely used non-invasive tool to study and modulate human brain functions. However, TMS-evoked activity of individual neurons has remained largely inaccessible due to the large TMS-induced electromagnetic fields. Here, we present a general method providing direct in vivo electrophysiological access to TMS-evoked neuronal activity 0.8-1 ms after TMS onset. We translated human single-pulse TMS to rodents and unveiled time-grained evoked activities of motor cortex layer V neurons that show high-frequency spiking within the first 6 ms depending on TMS-induced current orientation and a multiphasic spike-rhythm alternating between excitation and inhibition in the 6-300 ms epoch, all of which can be linked to various human TMS responses recorded at the level of spinal cord and muscles. The advance here facilitates a new level of insight into the TMS-brain interaction that is vital for developing this non-invasive tool to purposefully explore and effectively treat the human brain.

  3. Adaptation to Cortical Noise Induced by Transcranial Magnetic Stimulation to the Occipital Lobe

    Directory of Open Access Journals (Sweden)

    David Heslip

    2012-05-01

    Full Text Available Transcranial magnetic stimulation (TMS is increasingly used as a method to modify and study functional brain activity. However, results from various studies have produced conflicting theories on how TMS of cortical tissue influences ongoing visual processing. To investigate this issue, single pulse TMS was applied over left V1 in five healthy subjects during an orientation discrimination task (vertical vs. horizontal using a Gabor patch (2 c/deg, presented 6° in the right visual field. Stimulus contrast was set to each individual's threshold, measured in the absence of TMS. When TMS was applied over V1 performance decreased in all observers (by 1.2–8.7% compared to accuracy levels obtained during stimulation of a control site (Cz. Crucially, accuracy levels during V1 stimulation gradually improved across blocks of 200 trials in some subjects, whereas performance remained stable during control site stimulation. In contrast, this pattern of recovery was not found in an analogous backward masking paradigm, using a brief visual noise mask instead of a TMS pulse. These results show that that the magnitude of TMS disruption can dissipate with repeated stimulation. This suggests that future studies using this technique should minimise the length of TMS exposure within each session to maximise its effectiveness. Our results show that the visual system can adapt dynamically to increased internal noise levels, minimising the impact of TMS induced cortical activity on sensory judgments.

  4. Protection of workers during medical application of transcranial magnetic stimulation

    International Nuclear Information System (INIS)

    Mischke, Marian

    2017-01-01

    Transcranial magnetic stimulation (TMS) is used in various applications in medicine. TMS is accompanied by relevant exposures by (extremely) low frequency magnetic fields. The applications can pose a threat to workers' health and safety at work through direct and indirect effects. Since the end of last year, the EMFV has been published to specify the obligations of the employer in association to ''Arbeitsschutzgesetz'' with regards to electromagnetic fields. Based on conventional types of equipment for the TMS, a possible procedure is presented for the employer to fulfill his duties.

  5. Interdisciplinary approaches of transcranial magnetic stimulation applied to a respiratory neuronal circuitry model.

    Directory of Open Access Journals (Sweden)

    Stéphane Vinit

    Full Text Available Respiratory related diseases associated with the neuronal control of breathing represent life-threatening issues and to date, no effective therapeutics are available to enhance the impaired function. The aim of this study was to determine whether a preclinical respiratory model could be used for further studies to develop a non-invasive therapeutic tool applied to rat diaphragmatic neuronal circuitry. Transcranial magnetic stimulation (TMS was performed on adult male Sprague-Dawley rats using a human figure-of-eight coil. The largest diaphragmatic motor evoked potentials (MEPdia were recorded when the center of the coil was positioned 6 mm caudal from Bregma, involving a stimulation of respiratory supraspinal pathways. Magnetic shielding of the coil with mu metal reduced magnetic field intensities and improved focality with increased motor threshold and lower amplitude recruitment curve. Moreover, transynaptic neuroanatomical tracing with pseudorabies virus (applied to the diaphragm suggest that connections exist between the motor cortex, the periaqueductal grey cell regions, several brainstem neurons and spinal phrenic motoneurons (distributed in the C3-4 spinal cord. These results reveal the anatomical substrate through which supraspinal stimulation can convey descending action potential volleys to the spinal motoneurons (directly or indirectly. We conclude that MEPdia following a single pulse of TMS can be successfully recorded in the rat and may be used in the assessment of respiratory supraspinal plasticity. Supraspinal non-invasive stimulations aimed to neuromodulate respiratory circuitry will enable new avenues of research into neuroplasticity and the development of therapies for respiratory dysfunction associated with neural injury and disease (e.g. spinal cord injury, amyotrophic lateral sclerosis.

  6. Transcranial magnetic stimulation--may be useful as a preoperative screen of motor tract function.

    Science.gov (United States)

    Galloway, Gloria M; Dias, Brennan R; Brown, Judy L; Henry, Christina M; Brooks, David A; Buggie, Ed W

    2013-08-01

    Transcranial motor stimulation with noninvasive cortical surface stimulation, using a high-intensity magnetic field referred to as transcranial magnetic stimulation generally, is considered a nonpainful technique. In contrast, transcranial electric stimulation of the motor tracts typically cannot be done in unanesthesized patients. Intraoperative monitoring of motor tract function with transcranial electric stimulation is considered a standard practice in many institutions for patients during surgical procedures in which there is potential risk of motor tract impairment so that the risk of paraplegia or paraparesis can be reduced. Because transcranial electric stimulation cannot be typically done in the outpatient setting, transcranial magnetic stimulation may be able to provide a well-tolerated method for evaluation of the corticospinal motor tracts before surgery. One hundred fifty-five patients aged 5 to 20 years were evaluated preoperatively with single-stimulation nonrepetitive transcranial magnetic stimulation for preoperative assessment. The presence of responses to transcranial magnetic stimulation reliably predicted the presence of responses to transcranial electric stimulation intraoperatively. No complications occurred during the testing, and findings were correlated to the clinical history and used in the setup of the surgical monitoring.

  7. Repetitive Transcranial Magnetic Stimulation in Patients with Hereditary Spastic Paraplegia

    Directory of Open Access Journals (Sweden)

    Mehmet Ağırman

    2011-06-01

    Full Text Available Hereditary spastic paraplegia (HSPP is a heterogeneous genetic disease characterized by progressive spasticity of lower extremities. Spasticity is a major cause of long-term disability in HSPP and significantly affects the functional life of patients. Repetitive transcranial magnetic stimulation (rTMS is widely used in diagnosis and treatment of many neurological and psychiatric diseases. Although the positive impacts of rTMS for spasticity have been reported, no study has been found on HSPP. We present two HSPP patients treated with low frequency rTMS (20 minutes at a frequency of 1 Hz (1200 pulses, for a period of 10 treatment sessions

  8. Repetitive Transcranial Magnetic Stimulation in Patients with Hereditary Spastic Paraplegia

    Directory of Open Access Journals (Sweden)

    Mehmet Ağırman

    2011-06-01

    Full Text Available Hereditary spastic paraplegia (HSPP is a heterogeneous genetic disease characterized by progressive spasticity of lower extremities. Spasticity is a major cause of long-term disability in HSPP and significantly affects the functional life of patients. Repetitive transcranial magnetic stimulation (rTMS is widely used in diagnosis and treatment of many neurological and psychiatric diseases. Although the positive impacts of rTMS for spasticity have been reported, no study has been found on HSPP. We present two HSPP patients treated with low frequency rTMS (20 minutes at a frequency of 1 Hz (1200 pulses, for a period of 10 treatment sessions.

  9. Four-pulse transcranial magnetic stimulation using multiple conditioning inputs. Normative MEP responses.

    Science.gov (United States)

    Calancie, Blair; Wang, Dongliang; Young, Eufrosina; Alexeeva, Natalia

    2018-04-01

    A four-pulse pattern of transcranial magnetic stimulation (TMS) was compared to traditional dual-pulse TMS for its ability to modulate motor cortical excitability. This novel pattern consisted of a three-pulse train of subthreshold conditioning pulses followed by a suprathreshold test pulse (i.e., SC-T). The intervals between these superconditioning (SC) pulses (1, 3, or 6 ms) and the follow-on test pulse (1, 3, 10, or 25 ms) were varied, and the resultant MEPs were compared to those elicited by: (1) single-pulse TMS; and (2) dual-pulse conditioning-test (C-T) TMS with either short (3 ms) or long (10 ms) intervals to elicit short-interval intracortical inhibition (SICI) or intracortical facilitation (ICF), respectively. Testing included abductor pollicis brevis (APB) and tibialis anterior (TA) in 15 neurologically normal adults. For superconditioning inputs, 10 ms test intervals caused especially strong facilitation of the test MEP, while 1 ms test intervals were particularly effective at causing inhibition of the test response. For both muscles and across all subjects, the most effective of the 12 SC-T inputs tested for causing either facilitation or inhibition was-with rare exception-superior to the dual-pulse TMS input for causing facilitation (i.e., ICF) or inhibition (i.e., SICI), while the overall magnitude of effect was more pronounced in APB compared to TA. Nevertheless, after normalization, the impact of a superconditioning input train on the test MEP was similar in APB and TA muscles, suggesting similar mechanisms of action. Limited findings from a single subject with amyotrophic lateral sclerosis (ALS) are included to further illustrate the potential advantages of using a train of conditioning pulses preceding a TMS test pulse to selectively investigate abnormal motor cortical excitatory and inhibitory circuitry.

  10. Modulation of corticospinal excitability by transcranial magnetic stimulation in children and adolescents with autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Lindsay M Oberman

    2014-08-01

    Full Text Available The developmental pathophysiology of Autism Spectrum Disorders (ASD is currently not fully understood. However, multiple lines of evidence suggest that the behavioral phenotype may result from dysfunctional inhibitory control over excitatory synaptic plasticity. Consistent with this claim, previous studies indicate that adults with Asperger’s Syndrome show an abnormally extended modulation of corticospinal excitability following a train of repetitive transcranial magnetic stimulation (rTMS. As ASD is a developmental disorder, the current study aimed to explore the effect of development on the duration of modulation of corticospinal excitability in children and adolescents with ASD. Additionally, as the application of rTMS to the understanding and treatment of pediatric neurological and psychiatric disorders is an emerging field, this study further sought to provide evidence for the safety and tolerability of rTMS in children and adolescents with ASD. Corticospinal excitability was measured by applying single pulses of TMS to the primary motor cortex both before and following a 40 second train of continuous theta burst stimulation. 19 high-functioning males ages 9-18 with ASD participated in this study. Results from this study reveal a positive linear relationship between age and duration of modulation of rTMS after-effects. Specifically we found that the older participants had a longer lasting response. Furthermore, though the specific protocol employed typically suppresses corticospinal excitability in adults, more than one third of our sample had a paradoxical facilitatory response to the stimulation. Results support the safety and tolerability of rTMS in pediatric clinical populations. Data also support published theories implicating aberrant plasticity and GABAergic dysfunction in this population.

  11. Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping

    Science.gov (United States)

    Peterchev, Angel V.; DʼOstilio, Kevin; Rothwell, John C.; Murphy, David L.

    2014-10-01

    Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with a lower voltage rating than prior cTMS devices. Main results. cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The near-zero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (\\lt 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in ten healthy volunteers. Significance. The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool.

  12. Usefulness of Transcranial Magnetic Stimulation to Assess Motor Function in Patients With Parkinsonism.

    Science.gov (United States)

    Park, Jaechan; Chang, Won Hyuk; Cho, Jin Whan; Youn, Jinyoung; Kim, Yun Kwan; Kim, Sun Woong; Kim, Yun-Hee

    2016-02-01

    To investigate the clinical significance of upper and lower extremity transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) in patients with parkinsonism. Twenty patients (14 men, 6 women; mean age 70.5±9.1 years) suffering from parkinsonism were included in this study. All participants underwent single-pulse TMS session to assess the corticospinal excitability of the upper and lower extremity motor cortex. The resting motor threshold (RMT) was defined as the lowest stimulus intensity able to evoke MEPs of an at least 50 µV peak-to-peak amplitude in 5 of 10 consecutive trials. Five sweeps of MEPs at 120% of the RMT were performed, and the mean amplitude and latency of the MEPs were calculated. Patients were also assessed using the Unified Parkinson's Disease Rating Scale part III (UPDRS-III) and the 5-meter Timed Up and Go (5m-TUG) test. There was a significant positive correlation between the RMTs of MEPs in the upper and lower extremities (r=0.612, p=0.004) and between the amplitude of MEPs in the upper and lower extremities (r=0.579, p=0.007). The RMT of upper extremity MEPs showed a significant negative relationship with the UPDRS-III score (r=-0.516, p=0.020). In addition, RMTs of lower extremity MEPs exhibited a negative relationship with the UPDRS-III score, but the association was not statistically significant (r=-406, p=0.075). These results indicated that the RMT of MEPs reflect the severity of motor dysfunction in patients with parkinsonism. MEP is a potential quantitative, electrodiagnostic method to assess motor function in patients with parkinsonism.

  13. Safety of Transcranial Magnetic Stimulation in Parkinson’s Disease: A Review of the Literature

    Science.gov (United States)

    VonLoh, Matthew; Chen, Robert; Kluger, Benzi

    2013-01-01

    Background Transcranial magnetic stimulation (TMS) has been used in both physiological studies and, more recently, the therapy of Parkinson’s Disease (PD). Prior TMS studies in healthy subjects and other patient populations demonstrate a slight risk of seizures and other adverse events. Our goal was to estimate these risks and document other safety concerns specific to PD patients. Methods We performed an English-Language literature search through PudMed to review all TMS studies involving PD patients. We documented any seizures or other adverse events associated with these studies. Crude risks were calculated per subject and per session of TMS. Results We identified 84 single pulse (spTMS) and/or paired pulse (ppTMS) TMS studies involving 1091 patients and 77 repetitive TMS (rTMS) studies involving 1137 patients. Risk of adverse events was low in all protocols. spTMS and ppTMS risk per patient for any adverse event was 0.0018 (95% CI: 0.0002 – 0.0066) per patient and no seizures were encountered. Risk of an adverse event from rTMS was 0.040 (95% CI: 0.029 – 0.053) per patient and no seizures were reported. Other adverse events included transient headaches, scalp pain, tinnitus, nausea, increase in pre-existing pain, and muscle jerks. Transient worsening of Parkinsonian symptoms was noted in one study involving rTMS of the supplementary motor area (SMA). Conclusion We conclude that current TMS and rTMS protocols do not pose significant risks to PD patients. We would recommend that TMS users in this population follow the most recent safety guidelines but do not warrant additional precautions. PMID:23473718

  14. Safety of transcranial magnetic stimulation in Parkinson's disease: a review of the literature.

    Science.gov (United States)

    Vonloh, Matthew; Chen, Robert; Kluger, Benzi

    2013-06-01

    Transcranial magnetic stimulation (TMS) has been used in both physiological studies and, more recently, the therapy of Parkinson's disease (PD). Prior TMS studies in healthy subjects and other patient populations demonstrate a slight risk of seizures and other adverse events. Our goal was to estimate these risks and document other safety concerns specific to PD patients. We performed an English-Language literature search through PudMed to review all TMS studies involving PD patients. We documented any seizures or other adverse events associated with these studies. Crude risks were calculated per subject and per session of TMS. We identified 84 single pulse (spTMS) and/or paired-pulse (ppTMS) TMS studies involving 1091 patients and 77 repetitive TMS (rTMS) studies involving 1137 patients. Risk of adverse events was low in all protocols. spTMS and ppTMS risk per patient for any adverse event was 0.0018 (95% CI: 0.0002-0.0066) per patient and no seizures were encountered. Risk of an adverse event from rTMS was 0.040 (95% CI: 0.029-0.053) per patient and no seizures were reported. Other adverse events included transient headaches, scalp pain, tinnitus, nausea, increase in pre-existing pain, and muscle jerks. Transient worsening of Parkinsonian symptoms was noted in one study involving rTMS of the supplementary motor area (SMA). We conclude that current TMS and rTMS protocols do not pose significant risks to PD patients. We would recommend that TMS users in this population follow the most recent safety guidelines but do not warrant additional precautions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Transcranial magnetic stimulation over posterior parietal cortex disrupts transsaccadic memory of multiple objects.

    Science.gov (United States)

    Prime, Steven L; Vesia, Michael; Crawford, J Douglas

    2008-07-02

    The posterior parietal cortex (PPC) plays a role in spatial updating of goals for eye and arm movements across saccades, but less is known about its role in updating perceptual memory. We reported previously that transsaccadic memory has a capacity for storing the orientations of three to four Gabor patches either within a single fixation (fixation task) or between separate fixations (saccade task). Here, we tested the role of the PPC in transsaccadic memory in eight subjects by simultaneously applying single-pulse transcranial magnetic stimulation (TMS) over the right and left PPC, over several control sites, and comparing these to behavioral controls with no TMS. In TMS trials, we randomly delivered pulses at one of three different time intervals around the time of the saccade, or at an equivalent time in the fixation task. Controls confirmed that subjects could normally retain at least three visual features. TMS over the left PPC and a control site had no significant effect on this performance. However, TMS over the right PPC disrupted memory performance in both tasks. This TMS-induced effect was most disruptive in the saccade task, in particular when stimulation coincided more closely with saccade timing. Here, the capacity to compare presaccadic and postsaccadic features was reduced to one object, as expected if the spatial aspect of memory was disrupted. This finding suggests that right PPC plays a role in the spatial processing involved in transsaccadic memory of visual features. We propose that this process uses saccade-related feedback signals similar to those observed in spatial updating.

  16. Repetitive Transcranial Magnetic Stimulation, Cognition, and Multiple Sclerosis: An Overview

    Directory of Open Access Journals (Sweden)

    Grigorios Nasios

    2018-01-01

    Full Text Available Multiple sclerosis (MS affects cognition in the majority of patients. A major aspect of the disease is brain volume loss (BVL, present in all phases and types (relapsing and progressive of the disease and linked to both motor and cognitive disabilities. Due to the lack of effective pharmacological treatments for cognition, cognitive rehabilitation and other nonpharmacological interventions such as repetitive transcranial magnetic stimulation (rTMS have recently emerged and their potential role in functional connectivity is studied. With recently developed advanced neuroimaging and neurophysiological techniques, changes related to alterations of the brain’s functional connectivity can be detected. In this overview, we focus on the brain’s functional reorganization in MS, theoretical and practical aspects of rTMS utilization in humans, and its potential therapeutic role in treating cognitively impaired MS patients.

  17. Transcranial magnetic stimulation: applications in basic neuroscience and neuropsychopharmacology.

    Science.gov (United States)

    Lisanby, Sarah H.; Luber, Bruce; Perera, Tarique; Sackeim, Harold A.

    2000-09-01

    Introduced 15 years ago, transcranial magnetic stimulation (TMS) is a non-invasive means of stimulating the cortex that has proved to be a unique tool for probing brain-behaviour relationships. While a therapeutic role for TMS in neuropsychiatry is uncertain, the utility of TMS in studying brain function has been demonstrated in diverse neuroscience applications. We review studies in animals on the mechanisms of action of TMS, and present a summary of the applications of TMS in basic neuroscience. TMS is still a relatively young technique, and unanswered questions remain regarding its acute and chronic impact on neural excitability and various aspects of brain function. Nonetheless, recent work with TMS has demonstrated its unique role in complementing other tools for studying brain function. As a brain intervention tool, TMS holds the promise of moving beyond correlative studies to help define the functional role of cortical regions in selected cognitive and affective processes.

  18. Design of a dynamic transcranial magnetic stimulation coil system.

    Science.gov (United States)

    Ge, Sheng; Jiang, Ruoli; Wang, Ruimin; Chen, Ji

    2014-08-01

    To study the brain activity at the whole-head range, transcranial magnetic stimulation (TMS) researchers need to investigate brain activity over the whole head at multiple locations. In the past, this has been accomplished with multiple single TMS coils that achieve quasi whole-head array stimulation. However, these designs have low resolution and are difficult to position and control over the skull. In this study, we propose a new dynamic whole-head TMS mesh coil system. This system was constructed using several sagittal and coronal directional wires. Using both simulation and real experimental data, we show that by varying the current direction and strength of each wire, this new coil system can form both circular coils or figure-eight coils that have the same features as traditional TMS coils. Further, our new system is superior to current coil systems because stimulation parameters such as size, type, location, and timing of stimulation can be dynamically controlled within a single experiment.

  19. Sensorimotor Integration During Motor Learning: Transcranial Magnetic Stimulation Studies.

    Science.gov (United States)

    Matur, Zeliha; Öge, A Emre

    2017-12-01

    The effect of sensory signals coming from skin and muscle afferents on the sensorimotor cortical networks is entitled as sensory-motor integration (SMI). SMI can be studied electrophysiologically by the motor cortex excitability changes in response to peripheral sensory stimulation. These changes include the periods of short afferent inhibition (SAI), afferent facilitation (AF), and late afferent inhibition (LAI). During the early period of motor skill acquisition, motor cortex excitability increases and changes occur in the area covered by the relevant zone of the motor cortex. In the late period, these give place to the morphological changes, such as synaptogenesis. SAI decreases during learning the motor skills, while LAI increases during motor activity. In this review, the role of SMI in the process of motor learning and transcranial magnetic stimulation techniques performed for studying SMI is summarized.

  20. Real-Time Prediction of Observed Action Requires Integrity of the Dorsal Premotor Cortex: Evidence From Repetitive Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Brich, Louisa F M; Bächle, Christine; Hermsdörfer, Joachim; Stadler, Waltraud

    2018-01-01

    Studying brain mechanisms underlying the prediction of observed action, the dorsal premotor cortex (PMd) has been suggested a key area. The present study probed this notion using repetitive transcranial magnetic stimulation (rTMS) to test whether interference in this area would affect the accuracy in predicting the time course of object directed actions performed with the right hand. Young and healthy participants observed actions in short videos. These were briefly occluded from view for 600 ms and resumed immediately afterwards. The task was to continue the action mentally and to indicate after each occlusion, whether the action was resumed at the right moment (condition in-time) or shifted. In a first run, single-pulse transcranial magnetic stimulation (sTMS) was delivered over the left primary hand-area during occlusion. In the second run, rTMS over the left PMd was applied during occlusion in half of the participants [experimental group (EG)]. The control group (CG) received sham-rTMS over the same area. Under rTMS, the EG predicted less trials correctly than in the sTMS run. Sham-rTMS in the CG had no effects on prediction. The interference in PMd interacted with the type of manipulation applied to the action's time course occasionally during occlusion. The performance decrease of the EG was most pronounced in conditions in which the continuations after occlusions were too late in the action's course. The present results extend earlier findings suggesting that real-time action prediction requires the integrity of the PMd. Different functional roles of this area are discussed. Alternative interpretations consider either simulation of specific motor programming functions or the involvement of a feature-unspecific predictor.

  1. Real-Time Prediction of Observed Action Requires Integrity of the Dorsal Premotor Cortex: Evidence From Repetitive Transcranial Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Louisa F. M. Brich

    2018-03-01

    Full Text Available Studying brain mechanisms underlying the prediction of observed action, the dorsal premotor cortex (PMd has been suggested a key area. The present study probed this notion using repetitive transcranial magnetic stimulation (rTMS to test whether interference in this area would affect the accuracy in predicting the time course of object directed actions performed with the right hand. Young and healthy participants observed actions in short videos. These were briefly occluded from view for 600 ms and resumed immediately afterwards. The task was to continue the action mentally and to indicate after each occlusion, whether the action was resumed at the right moment (condition in-time or shifted. In a first run, single-pulse transcranial magnetic stimulation (sTMS was delivered over the left primary hand-area during occlusion. In the second run, rTMS over the left PMd was applied during occlusion in half of the participants [experimental group (EG]. The control group (CG received sham-rTMS over the same area. Under rTMS, the EG predicted less trials correctly than in the sTMS run. Sham-rTMS in the CG had no effects on prediction. The interference in PMd interacted with the type of manipulation applied to the action’s time course occasionally during occlusion. The performance decrease of the EG was most pronounced in conditions in which the continuations after occlusions were too late in the action’s course. The present results extend earlier findings suggesting that real-time action prediction requires the integrity of the PMd. Different functional roles of this area are discussed. Alternative interpretations consider either simulation of specific motor programming functions or the involvement of a feature-unspecific predictor.

  2. BOLD-fMRI response vs. transcranial magnetic stimulation (TMS) pulse-train length: testing for linearity.

    Science.gov (United States)

    Bohning, Daryl E; Shastri, Ananda; Lomarev, Mikhail P; Lorberbaum, Jeffrey P; Nahas, Ziad; George, Mark S

    2003-03-01

    To measure motor and auditory cortex blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) response to impulse-like transcranial magnetic stimulation (TMS) pulses as a function of train length. Interleaved with fMRI at 1.5 T, TMS pulses 0.3-msec long were applied at 1 Hz to the motor cortex area for thumb. Six subjects were studied in a TR = 1 second session administering trains of 1, 2, 4, 8, and 16 pulses, and a TR = 3 seconds session administering trains of 1, 2, 4, 8, 16, and 24 pulses. A simple hemodynamic model with finite recovery and saturation was used to quantitatively characterize the BOLD-fMRI response as a function of train length. In both the activations directly induced in motor cortex by TMS and the indirect activations in auditory cortex caused by the sound of the TMS coil firing, the BOLD-fMRI responses to multiple pulses were well described by a summation of single-pulse impulse functions. Up to 24 discrete pulses, BOLD-fMRI response to 1 Hz TMS in both motor cortex and auditory cortex were consistent with a linear increase in amplitude and length with train length, possibly suggesting that stimuli of 1 to 2 seconds may be too long to represent impulses. Copyright 2003 Wiley-Liss, Inc.

  3. Understanding the biophysical effects of transcranial magnetic stimulation on brain tissue: the bridge between brain stimulation and cognition.

    Science.gov (United States)

    Neggers, Sebastiaan F W; Petrov, Petar I; Mandija, Stefano; Sommer, Iris E C; van den Berg, Nico A T

    2015-01-01

    Transcranial magnetic stimulation (TMS) is rapidly being adopted in neuroscience, medicine, psychology, and biology, for basic research purposes, diagnosis, and therapy. However, a coherent picture of how TMS affects neuronal processing, and especially how this in turn influences behavior, is still largely unavailable despite several studies that investigated aspects of the underlying neurophysiological effects of TMS. Perhaps as a result from this "black box approach," TMS studies show a large interindividual variability in applied paradigms and TMS treatment outcome can be quite variable, hampering its general efficacy and introduction into the clinic. A better insight into the biophysical, neuronal, and cognitive mechanisms underlying TMS is crucial in order to apply it effectively in the clinic and to increase our understanding of brain-behavior relationship. Therefore, computational and experimental efforts have been started recently to understand and control the effect TMS has on neuronal functioning. Especially, how the brain shapes magnetic fields induced by a TMS coil, how currents are generated locally in the cortical surface, and how they interact with complex functional neuronal circuits within and between brain areas are crucial to understand the observed behavioral changes and potential therapeutic effects resulting from TMS. Here, we review the current knowledge about the biophysical underpinnings of single-pulse TMS and argue how to move forward to fully understand and exploit the powerful technique that TMS can be. © 2015 Elsevier B.V. All rights reserved.

  4. Medical devices; neurological devices; classification of the transcranial magnetic stimulator for headache. Final order.

    Science.gov (United States)

    2014-07-08

    The Food and Drug Administration (FDA) is classifying the transcranial magnetic stimulator for headache into class II (special controls). The special controls that will apply to the device are identified in this order, and will be part of the codified language for the transcranial magnetic stimulator for headache classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

  5. A feasible repetitive transcranial magnetic stimulation clinical protocol in migraine prevention

    Directory of Open Access Journals (Sweden)

    Shawn Zardouz

    2016-10-01

    Full Text Available Objective: This case series was conducted to determine the clinical feasibility of a repetitive transcranial magnetic stimulation protocol for the prevention of migraine (with and without aura. Methods: Five patients with migraines underwent five repetitive transcranial magnetic stimulation sessions separated in 1- to 2-week intervals for a period of 2 months at a single tertiary medical center. Repetitive transcranial magnetic stimulation was applied to the left motor cortex with 2000 pulses (20 trains with 1s inter-train interval delivered per session, at a frequency of 10 Hz and 80% resting motor threshold. Pre- and post-treatment numerical rating pain scales were collected, and percent reductions in intensity, frequency, and duration were generated. Results: An average decrease in 37.8%, 32.1%, and 31.2% were noted in the intensity, frequency, and duration of migraines post-repetitive transcranial magnetic stimulation, respectively. A mean decrease in 1.9±1.0 (numerical rating pain scale ± standard deviation; range: 0.4–2.8 in headache intensity scores was noted after the repetitive transcranial magnetic stimulation sessions. Conclusion: The tested repetitive transcranial magnetic stimulation protocol is a well-tolerated, safe, and effective method for migraine prevention.

  6. A feasible repetitive transcranial magnetic stimulation clinical protocol in migraine prevention.

    Science.gov (United States)

    Zardouz, Shawn; Shi, Lei; Leung, Albert

    2016-01-01

    This case series was conducted to determine the clinical feasibility of a repetitive transcranial magnetic stimulation protocol for the prevention of migraine (with and without aura). Five patients with migraines underwent five repetitive transcranial magnetic stimulation sessions separated in 1- to 2-week intervals for a period of 2 months at a single tertiary medical center. Repetitive transcranial magnetic stimulation was applied to the left motor cortex with 2000 pulses (20 trains with 1s inter-train interval) delivered per session, at a frequency of 10 Hz and 80% resting motor threshold. Pre- and post-treatment numerical rating pain scales were collected, and percent reductions in intensity, frequency, and duration were generated. An average decrease in 37.8%, 32.1%, and 31.2% were noted in the intensity, frequency, and duration of migraines post-repetitive transcranial magnetic stimulation, respectively. A mean decrease in 1.9±1.0 (numerical rating pain scale ± standard deviation; range: 0.4-2.8) in headache intensity scores was noted after the repetitive transcranial magnetic stimulation sessions. The tested repetitive transcranial magnetic stimulation protocol is a well-tolerated, safe, and effective method for migraine prevention.

  7. Transcranial Magnetic Stimulation-coil design with improved focality

    Science.gov (United States)

    Rastogi, P.; Lee, E. G.; Hadimani, R. L.; Jiles, D. C.

    2017-05-01

    Transcranial Magnetic Stimulation (TMS) is a technique for neuromodulation that can be used as a non-invasive therapy for various neurological disorders. In TMS, a time varying magnetic field generated from an electromagnetic coil placed on the scalp is used to induce an electric field inside the brain. TMS coil geometry plays an important role in determining the focality and depth of penetration of the induced electric field responsible for stimulation. Clinicians and basic scientists are interested in stimulating a localized area of the brain, while minimizing the stimulation of surrounding neural networks. In this paper, a novel coil has been proposed, namely Quadruple Butterfly Coil (QBC) with an improved focality over the commercial Figure-8 coil. Finite element simulations were conducted with both the QBC and the conventional Figure-8 coil. The two coil's stimulation profiles were assessed with 50 anatomically realistic MRI derived head models. The coils were positioned on the vertex and the scalp over the dorsolateral prefrontal cortex to stimulate the brain. Computer modeling of the coils has been done to determine the parameters of interest-volume of stimulation, maximum electric field, location of maximum electric field and area of stimulation across all 50 head models for both coils.

  8. Deep brain transcranial magnetic stimulation using variable "Halo coil" system

    Science.gov (United States)

    Meng, Y.; Hadimani, R. L.; Crowther, L. J.; Xu, Z.; Qu, J.; Jiles, D. C.

    2015-05-01

    Transcranial Magnetic Stimulation has the potential to treat various neurological disorders non-invasively and safely. The "Halo coil" configuration can stimulate deeper regions of the brain with lower surface to deep-brain field ratio compared to other coil configurations. The existing "Halo coil" configuration is fixed and is limited in varying the site of stimulation in the brain. We have developed a new system based on the current "Halo coil" design along with a graphical user interface system that enables the larger coil to rotate along the transverse plane. The new system can also enable vertical movement of larger coil. Thus, this adjustable "Halo coil" configuration can stimulate different regions of the brain by adjusting the position and orientation of the larger coil on the head. We have calculated magnetic and electric fields inside a MRI-derived heterogeneous head model for various positions and orientations of the coil. We have also investigated the mechanical and thermal stability of the adjustable "Halo coil" configuration for various positions and orientations of the coil to ensure safe operation of the system.

  9. Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain

    Science.gov (United States)

    Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

    1998-12-01

    Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.

  10. POSSIBLE MECHANISMS UNDERLYING THE THERAPEUTIC EFFECTS OF TRANSCRANIAL MAGNETIC STIMULATION

    Directory of Open Access Journals (Sweden)

    Alexander eChervyakov

    2015-06-01

    Full Text Available Transcranial magnetic stimulation (TMS is an effective method used to diagnose and treat many neurological disorders. Although repetitive TMS (rTMS has been used to treat a variety of serious pathological conditions including stroke, depression, Parkinson's disease, epilepsy, pain, and migraines, the pathophysiological mechanisms underlying the effects of long-term TMS remain unclear. In the present review, the effects of rTMS on neurotransmitters and synaptic plasticity are described, including the classic interpretations of TMS effects on synaptic plasticity via long-term potentiation (LTP and long-term depression (LTD. We also discuss the effects of rTMS on the genetic apparatus of neurons, glial cells and the prevention of neuronal death. The neurotrophic effects of rTMS on dendritic growth and sprouting and neurotrophic factors are described, including change in brain-derived neurotrophic factor (BDNF concentration under the influence of rTMS. Also, non-classical effects of TMS related to biophysical effects of magnetic fields are described, including the quantum effects, the magnetic spin effects, genetic magnetoreception, the macromolecular effects of TMS, and the electromagnetic theory of consciousness. Finally, we discuss possible interpretations of TMS effects according to dynamical systems theory. Evidence suggests that a rTMS-induced magnetic field should be considered a separate physical factor that can be impactful at the subatomic level and that rTMS is capable of significantly altering the reactivity of molecules (radicals. It is thought that these factors underlie the therapeutic benefits of therapy with TMS. Future research on these mechanisms will be instrumental to the development of more powerful and reliable TMS treatment protocols.

  11. A Single-Pulse Integrator

    DEFF Research Database (Denmark)

    Miller, Arne

    1974-01-01

    A single-pulse integrator is described. It gives a relative measure of the integral of the output signal from a coil monitor on the Risø 10 MeV linear accelerator, and displays the value on a digital voltmeter. The reproduccibility is found to be better than ±1% for an accelerated pulse charge...

  12. Coil optimisation for transcranial magnetic stimulation in realistic head geometry.

    Science.gov (United States)

    Koponen, Lari M; Nieminen, Jaakko O; Mutanen, Tuomas P; Stenroos, Matti; Ilmoniemi, Risto J

    Transcranial magnetic stimulation (TMS) allows focal, non-invasive stimulation of the cortex. A TMS pulse is inherently weakly coupled to the cortex; thus, magnetic stimulation requires both high current and high voltage to reach sufficient intensity. These requirements limit, for example, the maximum repetition rate and the maximum number of consecutive pulses with the same coil due to the rise of its temperature. To develop methods to optimise, design, and manufacture energy-efficient TMS coils in realistic head geometry with an arbitrary overall coil shape. We derive a semi-analytical integration scheme for computing the magnetic field energy of an arbitrary surface current distribution, compute the electric field induced by this distribution with a boundary element method, and optimise a TMS coil for focal stimulation. Additionally, we introduce a method for manufacturing such a coil by using Litz wire and a coil former machined from polyvinyl chloride. We designed, manufactured, and validated an optimised TMS coil and applied it to brain stimulation. Our simulations indicate that this coil requires less than half the power of a commercial figure-of-eight coil, with a 41% reduction due to the optimised winding geometry and a partial contribution due to our thinner coil former and reduced conductor height. With the optimised coil, the resting motor threshold of abductor pollicis brevis was reached with the capacitor voltage below 600 V and peak current below 3000 A. The described method allows designing practical TMS coils that have considerably higher efficiency than conventional figure-of-eight coils. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Research with Transcranial Magnetic Stimulation in the Treatment of Aphasia

    Science.gov (United States)

    Martin, Paula I; Naeser, Margaret A.; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Baker, Errol H.; Pascual-Leone, Alvaro

    2010-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has been used to improve language behavior, including naming, in stroke patients with chronic, nonfluent aphasia. Part 1 of this paper reviews functional imaging studies related to language recovery in aphasia. Part 2 reviews the rationale for using rTMS to treat nonfluent aphasia (based on functional imaging); and presents our current rTMS protocol. We present language results from our rTMS studies, and imaging results from overt naming fMRI scans obtained pre- and post- a series of rTMS treatments. Part 3 presents results from a pilot study where rTMS treatments were followed immediately by constraint-induced language therapy. Part 4 reviews our diffusion tensor imaging study that examined possible connectivity of arcuate fasciculus to different parts of Broca’s area (pars triangularis, PTr; pars opercularis, POp); and to ventral premotor cortex (vPMC). The potential role of mirror neurons in R POp and vPMC in aphasia recovery is discussed. PMID:19818232

  14. Transcranial magnetic stimulation and sleep disorders: pathophysiologic insights.

    Science.gov (United States)

    Nardone, Raffaele; Höller, Yvonne; Brigo, Francesco; Tezzon, Frediano; Golaszewski, Stefan; Trinka, Eugen

    2013-11-01

    The neural mechanisms underlying the development of the most common intrinsic sleep disorders are not completely known. Therefore, there is a great need for noninvasive tools which can be used to better understand the pathophysiology of these diseases. Transcranial magnetic stimulation (TMS) offers a method to noninvasively investigate the functional integrity of the motor cortex and its corticospinal projections in neurologic and psychiatric diseases. To date, TMS studies have revealed cortical and corticospinal dysfunction in several sleep disorders, with cortical hyperexcitability being a characteristic feature in some disorders (i.e., the restless legs syndrome) and cortical hypoexcitability being a well-established finding in others (i.e., obstructive sleep apnea syndrome narcolepsy). Several research groups also have applied TMS to evaluate the effects of pharmacologic agents, such as dopaminergic agent or wake-promoting substances. Our review will focus on the mechanisms underlying the generation of abnormal TMS measures in the different types of sleep disorders, the contribution of TMS in enhancing the understanding of their pathophysiology, and the potential diagnostic utility of TMS techniques. We also briefly discussed the possible future implications for improving therapeutic approaches. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Effect of Transcranial Magnetic Stimulation on Neuronal Networks

    Science.gov (United States)

    Unsal, Ahmet; Hadimani, Ravi; Jiles, David

    2013-03-01

    The human brain contains around 100 billion nerve cells controlling our day to day activities. Consequently, brain disorders often result in impairments such as paralysis, loss of coordination and seizure. It has been said that 1 in 5 Americans suffer some diagnosable mental disorder. There is an urgent need to understand the disorders, prevent them and if possible, develop permanent cure for them. As a result, a significant amount of research activities is being directed towards brain research. Transcranial Magnetic Stimulation (TMS) is a promising tool for diagnosing and treating brain disorders. It is a non-invasive treatment method that produces a current flow in the brain which excites the neurons. Even though TMS has been verified to have advantageous effects on various brain related disorders, there have not been enough studies on the impact of TMS on cells. In this study, we are investigating the electrophysiological effects of TMS on one dimensional neuronal culture grown in a circular pathway. Electrical currents are produced on the neuronal networks depending on the directionality of the applied field. This aids in understanding how neuronal networks react under TMS treatment.

  16. Modeling the effects of transcranial magnetic stimulation on cortical circuits.

    Science.gov (United States)

    Esser, Steve K; Hill, Sean L; Tononi, Giulio

    2005-07-01

    Transcranial magnetic stimulation (TMS) is commonly used to activate or inactivate specific cortical areas in a noninvasive manner. Because of technical constraints, the precise effects of TMS on cortical circuits are difficult to assess experimentally. Here, this issue is investigated by constructing a detailed model of a portion of the thalamocortical system and examining the effects of the simulated delivery of a TMS pulse. The model, which incorporates a large number of physiological and anatomical constraints, includes 33,000 spiking neurons arranged in a 3-layered motor cortex and over 5 million intra- and interlayer synaptic connections. The model was validated by reproducing several results from the experimental literature. These include the frequency, timing, dose response, and pharmacological modulation of epidurally recorded responses to TMS (the so-called I-waves), as well as paired-pulse response curves consistent with data from several experimental studies. The modeled responses to simulated TMS pulses in different experimental paradigms provide a detailed, self-consistent account of the neural and synaptic activities evoked by TMS within prototypical cortical circuits.

  17. Repetitive transcranial magnetic stimulation in treatment of post polio syndrome.

    Science.gov (United States)

    Pastuszak, Żanna; Piusińska-Macoch, Renata; Stępień, Adam; Czernicki, Zbigniew

    2017-11-05

    Post polio syndrome is a rare disease that occurs decades after polio virus infection. Repetitive transcranial magnetic stimulation (rTMS) is a treatment option with proved effectiveness in drug resistant depression. Possibly it can be helpful in therapy of other neurological diseases including post polio syndrome. To describe a case of patient diagnosed with post polio syndrome who was treated with rTMS stimulation with a good effect. Patient had rTMS stimulation of left prefrontal cortex twice a week for an eight weeks. Patient's health status was evaluated before treatment, after last rTMS session and after three months from the end of the treatment. Improvement of fatigue score, mood disturbances and motor functions was observed after treatment. rTMS can be an effective method in treatment of post polio syndrome but further studies with larger group need to be done to confirm that data. Copyright © 2017. Published by Elsevier Urban & Partner Sp. z o.o.

  18. Modulating functional and dysfunctional mentalizing by transcranial magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Tobias eSchuwerk

    2014-11-01

    Full Text Available Mentalizing, the ability to attribute mental states to others and oneself, is a cognitive function with high relevance for social interactions. Recent neuroscientific research has increasingly contributed to attempts to decompose this complex social cognitive function into constituting neurocognitive building blocks. Additionally, clinical research that focuses on social cognition to find links between impaired social functioning and neurophysiological deviations has accumulated evidence that mentalizing is affected in most psychiatric disorders. Recently, both lines of research have started to employ transcranial magnetic stimulation: the first to modulate mentalizing in order to specify its neurocognitive components, the latter to treat impaired mentalizing in clinical conditions. This review integrates findings of these two different approaches to draw a more detailed picture of the neurocognitive basis of mentalizing and its deviations in psychiatric disorders. Moreover, we evaluate the effectiveness of hitherto employed stimulation techniques and protocols, paradigms and outcome measures. Based on this overview we highlight new directions for future research on the neurocognitive basis of functional and dysfunctional social cognition.

  19. Transcranial Magnetic Stimulation for the Assessment of Neurodegenerative Disease.

    Science.gov (United States)

    Vucic, Steve; Kiernan, Matthew C

    2017-01-01

    Transcranial magnetic stimulation (TMS) is a noninvasive technique that has provided important information about cortical function across an array of neurodegenerative disorders, including Alzheimer's disease, frontotemporal dementia, Parkinson's disease, and related extrapyramidal disorders. Application of TMS techniques in neurodegenerative diseases has provided important pathophysiological insights, leading to the development of pathogenic and diagnostic biomarkers that could be used in the clinical setting and therapeutic trials. Abnormalities of TMS outcome measures heralding cortical hyperexcitability, as evidenced by a reduction of short-interval intracortical inhibition and increased in motor-evoked potential amplitude, have been consistently identified as early and intrinsic features of amyotrophic lateral sclerosis (ALS), preceding and correlating with the ensuing neurodegeneration. Cortical hyperexcitability appears to form the pathogenic basis of ALS, mediated by trans-synaptic glutamate-mediated excitotoxic mechanisms. As a consequence of these research findings, TMS has been developed as a potential diagnostic biomarker, capable of identifying upper motor neuronal pathology, at earlier stages of the disease process, and thereby aiding in ALS diagnosis. Of further relevance, marked TMS abnormalities have been reported in other neurodegenerative diseases, which have varied from findings in ALS. With time and greater utilization by clinicians, TMS outcome measures may prove to be of utility in future therapeutic trial settings across the neurodegenerative disease spectrum, including the monitoring of neuroprotective, stem-cell, and genetic-based strategies, thereby enabling assessment of biological effectiveness at early stages of drug development.

  20. Changes of blood lactate levels after repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Alagona, Giovanna; Coco, Marinella; Rapisarda, Giuseppe; Costanzo, Erminio; Maci, Tiziana; Restivo, Domenico; Maugeri, Antonino; Perciavalle, Vincenzo

    2009-01-30

    The objective was to study whether repetitive transcranial magnetic stimulation (rTMS) of the motor cortex could induce modification of peripheral blood lactate values. Nineteen young healthy volunteers were included; during the study, all subjects were at rest, sitting on a comfortable armchair. The muscular activation was evaluated by continuous electromyographic record. TMS was performed by using a circular coil at the vertex. Resting motor threshold (rMT) was defined as the lowest TMS intensity able to induce motor responses of an amplitude >50 microV in the relaxed contralateral target muscle in approximately 50% of 20 consecutive stimuli. Venous blood lactate values were measured before, immediately after and 10 min after a single session of low frequencies (1Hz for 15 min) rTMS (LF rTMS) or high frequency (20 Hz for 15 min) rTMS (HF rTMS). As expected, LF rTMS induced a decrease of motor cortex excitability, whereas HF rTMS evoked an increase of motor cortex excitability. However, in the present investigation we observed that both conditions are associated to a significant increase of blood lactate. Since in our experimental conditions we can exclude a muscular production of lactate, the significant increment of peripheral blood lactate values, observed 10 min after the end of the rTMS session, is probably due to the crossing by brain-produced lactate of the blood-brain barrier.

  1. Preoperative functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS)

    DEFF Research Database (Denmark)

    Hartwigsen, G.; Siebner, Hartwig R.; Stippich, C.

    2010-01-01

    of essential cortex, it cannot provide information preoperatively for surgical planning.Brain imaging techniques such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) are increasingly being used to localize functionally critical cortical......, if the stimulated cortex makes a critical contribution to the brain functions subserving the task. While the relationship between task and functional activation as revealed by fMRI is correlative in nature, the neurodisruptive effect of TMS reflects a causal effect on brain activity.The use of preoperative f...

  2. Methods of high current magnetic field generator for transcranial magnetic stimulation application

    Energy Technology Data Exchange (ETDEWEB)

    Bouda, N. R., E-mail: nybouda@iastate.edu; Pritchard, J.; Weber, R. J.; Mina, M. [Department of Electrical and Computer engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-05-07

    This paper describes the design procedures and underlying concepts of a novel High Current Magnetic Field Generator (HCMFG) with adjustable pulse width for transcranial magnetic stimulation applications. This is achieved by utilizing two different switching devices, the MOSFET and insulated gate bipolar transistor (IGBT). Results indicate that currents as high as ±1200 A can be generated with inputs of +/−20 V. Special attention to tradeoffs between field generators utilizing IGBT circuits (HCMFG{sub 1}) and MOSFET circuits (HCMFG{sub 2}) was considered. The theory of operation, design, experimental results, and electronic setup are presented and analyzed.

  3. Stimulus intensity for hand held and robotic transcranial magnetic stimulation.

    Science.gov (United States)

    Richter, Lars; Trillenberg, Peter; Schweikard, Achim; Schlaefer, Alexander

    2013-05-01

    Transcranial Magnetic Stimulation (TMS) is based on a changing magnetic field inducing an electric field in the brain. Conventionally, the TMS coil is mounted to a static holder and the subject is asked to avoid head motion. Additionally, head resting frames have been used. In contrast, our robotized TMS system employs active motion compensation (MC) to maintain the correct coil position. We study the effect of patient motion on TMS. In particular, we compare different coil positioning techniques with respect to the induced electric field. We recorded head motion for six subjects in three scenarios: (a) avoiding head motion, (b) using a head rest, and (c) moving the head freely. Subsequently, the motion traces were replayed using a second robot to move a sensor to measure the electric field in the target region. These head movements were combined with 2 types of coil positioning: (1) using a coil holder and (2) using robotized TMS with MC. After 30 min the induced electric field was reduced by 32.0% and 19.7% for scenarios (1a) and (1b), respectively. For scenarios (2a)-(2c) it was reduced by only 4.9%, 1.4% and 2.0%, respectively, which is a significant improvement (P < 0.05). Furthermore, the orientation of the induced field changed by 5.5°, 7.6°, 0.4°, 0.2°, 0.2° for scenarios (1a)-(2c). While none of the scenarios required rigid head fixation, using a simple holder to position a coil during TMS can lead to substantial deviations in the induced electric field. In contrast, robotic motion compensation results in clinically acceptable positioning throughout treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Assessment of Vascular Stent Heating with Repetitive Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Varnerin, Nicole; Mirando, David; Potter-Baker, Kelsey A; Cardenas, Jesus; Cunningham, David A; Sankarasubramanian, Vishwanath; Beall, Erik; Plow, Ela B

    2017-05-01

    A high proportion of patients with stroke do not qualify for repetitive transcranial magnetic stimulation (rTMS) clinical studies due to the presence of metallic stents. The ultimate concern is that any metal could become heated due to eddy currents. However, to date, no clinical safety data are available regarding the risk of metallic stents heating with rTMS. We tested the safety of common rTMS protocols (1 Hz and 10 Hz) with stents used commonly in stroke, nitinol and elgiloy. In our method, stents were tested in gelled saline at 2 different locations: at the center and at the lobe of the coil. In addition, at each location, stent heating was evaluated in 3 different orientations: parallel to the long axis of coil, parallel to the short axis of the coil, and perpendicular to the plane of the coil. We found that stents did not heat to more than 1°C with either 1 Hz rTMS or 10 Hz rTMS in any configuration or orientation. Heating in general was greater at the lobe when the stent was oriented perpendicularly. Our study represents a new method for ex vivo quantification of stent heating. We have found that heating of stents was well below the Food and Drug Administration standards of 2°C. Thus, our study paves the way for in vivo testing of rTMS (≤10 Hz) in the presence of implanted magnetic resonance imaging-compatible stents in animal studies. When planning human safety studies though, geometry, orientation, and location relative to the coil would be important to consider as well. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  5. Pulse Width Affects Scalp Sensation of Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Peterchev, Angel V; Luber, Bruce; Westin, Gregory G; Lisanby, Sarah H

    Scalp sensation and pain comprise the most common side effect of transcranial magnetic stimulation (TMS), which can reduce tolerability and complicate experimental blinding. We explored whether changing the width of single TMS pulses affects the quality and tolerability of the resultant somatic sensation. Using a controllable pulse parameter TMS device with a figure-8 coil, single monophasic magnetic pulses inducing electric field with initial phase width of 30, 60, and 120 µs were delivered in 23 healthy volunteers. Resting motor threshold of the right first dorsal interosseus was determined for each pulse width, as reported previously. Subsequently, pulses were delivered over the left dorsolateral prefrontal cortex at each of the three pulse widths at two amplitudes (100% and 120% of the pulse-width-specific motor threshold), with 20 repetitions per condition delivered in random order. After each pulse, subjects rated 0-to-10 visual analog scales for Discomfort, Sharpness, and Strength of the sensation. Briefer TMS pulses with amplitude normalized to the motor threshold were perceived as slightly more uncomfortable than longer pulses (with an average 0.89 point increase on the Discomfort scale for pulse width of 30 µs compared to 120 µs). The sensation of the briefer pulses was felt to be substantially sharper (2.95 points increase for 30 µs compared to 120 µs pulse width), but not stronger than longer pulses. As expected, higher amplitude pulses increased the perceived discomfort and strength, and, to a lesser degree the perceived sharpness. Our findings contradict a previously published hypothesis that briefer TMS pulses are more tolerable. We discovered that the opposite is true, which merits further study as a means of enhancing tolerability in the context of repetitive TMS. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Default Mode Network Mechanisms of Transcranial Magnetic Stimulation in Depression

    Science.gov (United States)

    Liston, Conor; Chen, Ashley C.; Zebley, Benjamin D.; Drysdale, Andrew T.; Gordon, Rebecca; Leuchter, Bruce; Voss, Henning U.; Casey, B.J.; Etkin, Amit; Dubin, Marc J.

    2014-01-01

    Background Repetitive transcranial magnetic stimulation (TMS) of the dorsolateral prefrontal cortex (DLPFC) is an established treatment for depression, but its underlying mechanism of action remains unknown. Abnormalities in two large-scale neuronal networks—the frontoparietal central executive network (CEN) and the medial prefrontal-medial parietal default mode network (DMN)—are consistent findings in depression and potential therapeutic targets for TMS. Here, we assessed the impact of TMS on activity in these networks and their relation to treatment response. Methods We used resting state functional magnetic resonance imaging (rs-fMRI) to measure functional connectivity within and between the DMN and CEN in 17 depressed patients, before and after a five-week course of TMS. Motivated by prior reports, we focused on connectivity seeded from the DLPFC and the subgenual cingulate, a key region closely aligned with the DMN in depression. Connectivity was also compared to a cohort of 35 healthy controls. Results Prior to treatment, functional connectivity in depressed patients was abnormally elevated within the DMN and diminished within the CEN, and connectivity between these two networks was altered. TMS normalized depression-related subgenual hyperconnectivity in the DMN but did not alter connectivity in the CEN. TMS also induced anticorrelated connectivity between the DLPFC and medial prefrontal DMN nodes. Baseline subgenual connectivity predicted subsequent clinical improvement. Conclusions TMS selectively modulates functional connectivity both within and between the CEN and DMN, and modulation of subgenual cingulate connectivity may play an important mechanistic role in alleviating depression. The results also highlight potential neuroimaging biomarkers for predicting treatment response. PMID:24629537

  7. An evaluation of factors affecting duration of treatment with repetitive transcranial magnetic stimulation for depression

    Directory of Open Access Journals (Sweden)

    Roni Broder Cohen

    2007-12-01

    Full Text Available Objective: To investigate the effects of repetitive transcranialmagnetic stimulation in patients with major depression who weresubmitted to this treatment during the period from 2000 to 2006.Methods: A retrospective study with 204 patients who underwenttreatment with repetitive transcranial magnetic stimulation, collectingdata from those who experienced remission (defined as a HDRS scoreequal to or lower than 7. The patients were followed for up to 6 monthsafter treatment. Mean duration of remission for this cohort of patientswas 70.2 (± 58.4 days. Results: The only variable associated withthe duration of remission in the linear regression model was numberof repetitive transcranial magnetic stimulation sessions. Conclusion:Our findings suggest that the greater the number of sessions, the longerthe duration of repetitive transcranial magnetic stimulation effects.Consequently, future research investigating the effects of repetitivetranscranial magnetic stimulation should explore this variable in orderto maximize the therapeutic effects of this new brain stimulationtechnique.

  8. 3-dimensional modeling of transcranial magnetic stimulation: Design and application

    Science.gov (United States)

    Salinas, Felipe Santiago

    Over the past three decades, transcranial magnetic stimulation (TMS) has emerged as an effective tool for many research, diagnostic and therapeutic applications in humans. TMS delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this dissertation, we present a thorough examination of the total electric field induced by TMS in air and a realistic head model with clinically relevant coil poses. In the first chapter, a detailed account of TMS coil wiring geometry was shown to provide significant improvements in the accuracy of primary E-field calculations. Three-dimensional models which accounted for the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed primary E-field models were accurate up to the surface of the coil body (within 0.5% of measured values) whereas simple models were often inadequate (up to 32% different from measured). In the second chapter, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3-D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistic head model was used to assess the effect of multiple surfaces on the total E-field. We found that secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes were predominantly between 25% and 45% of the primary E-fields magnitude. The direction of the secondary E

  9. Interaction of transcranial magnetic stimulation and electrical transmastoid stimulation in human subjects

    DEFF Research Database (Denmark)

    Taylor, Janet L; Petersen, Nicolas Caesar; Butler, Jane E

    2002-01-01

    was designed to determine whether the two stimuli activate the same descending axons. Responses to transcranial magnetic stimuli paired with electrical transmastoid stimuli were examined in biceps brachii in human subjects. Twelve interstimulus intervals (ISIs) from -6 ms (magnet before transmastoid) to 5 ms...

  10. Transcranial magnetic stimulation in lower motor neuron diseases.

    Science.gov (United States)

    Attarian, S; Azulay, J-Ph; Lardillier, D; Verschueren, A; Pouget, J

    2005-01-01

    To study the diagnostic value of transcranial magnetic stimulation (TMS) in a group of patients with lower motor neuron disease (LMND). Among LMND, several chronic immune mediate motor neuropathies may simulate amyotrophic lateral sclerosis (ALS). Forty patients with LMND were included TMS was performed at the first visit. The patients were seen prospectively every 3 months for a period of 1-4 years. Three different groups were distinguished at the end of follow-up: (1) ALS group with 7 patients, (2) Pure motor neuropathy with 14 patients and (3) Other LMND including 12 patients with hereditary spinal amyotrophy, 3 patients with Kennedy's disease and 4 patients with post-poliomyelitis. On the basis of the results of TMS variables, 6 out of 7 ALS patients had abnormality of silent period (SP) associated or not with abnormality of excitatory threshold or amplitude ratio. Patients with pure motor neuropathy had normal SP and amplitude ratio. Four out of 14 patients had increased central motor conduction time (CMCT), one had increased CMCT and excitatory threshold, and one patient had a slightly increased excitatory threshold. Considering the abnormality of TMS variables in the groups, SP, excitatory threshold, and amplitude ratio were chosen in a post-hoc attempt to select variables yielding high sensitivity and specificity. The overall sensitivity of TMS for diagnosis of ALS among LMND was 85.7%, its specificity was 93.9%. When only the abnormality of SP was taken into account, the sensitivity was unchanged. But the specificity was improved to 100%. TMS helped to distinguish suspected ALS from pure motor neuropathy.

  11. Assessing motor function in young children with transcranial magnetic stimulation.

    Science.gov (United States)

    Narayana, Shalini; Rezaie, Roozbeh; McAfee, Samuel S; Choudhri, Asim F; Babajani-Feremi, Abbas; Fulton, Stephen; Boop, Frederick A; Wheless, James W; Papanicolaou, Andrew C

    2015-01-01

    Accurate noninvasive assessment of motor function using functional MRI (fMRI) and magnetoencephalography (MEG) is a challenge in patients who are very young or who are developmentally delayed. In such cases, passive mapping of the sensorimotor cortex is performed under sedation. We examined the feasibility of using transcranial magnetic stimulation (TMS) as a motor mapping tool in awake children younger than 3 years of age. Six children underwent motor mapping with TMS while awake as well as passive sensorimotor mapping under conscious sedation with MEG during tactile stimulation (n = 5) and fMRI during passive hand movements (n = 4). Stimulation of the motor cortex via TMS successfully elicited evoked responses in contralateral hand muscles in 5 patients. The location of primary motor cortex in the precentral gyrus identified by TMS corresponded with the postcentral location of the primary sensory cortex identified by MEG in 2 patients and to the sensorimotor cortex identified by fMRI in 3 children. In this cohort, we demonstrate that TMS can illuminate abnormalities in motor physiology including motor reorganization. We also demonstrate the feasibility of using TMS-derived contralateral silent periods to approximate the location of motor cortex in the absence of an evoked response. When compared to chronological age, performance functioning level appears to be better in predicting successful mapping outcome with TMS. Our findings indicate that awake TMS is a safe alternative to MEG and fMRI performed under sedation to localize the motor cortex and provides additional insight into the underlying pathophysiology and motor plasticity in toddlers. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Severity of Depression Predicts Remission Rates Using Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Grammer, Geoffrey G; Kuhle, Andrew R; Clark, Caroline C; Dretsch, Michael N; Williams, Kathy A; Cole, Jeffrey T

    2015-01-01

    Multiple factors likely impact response and remission rates in the treatment of depression with repetitive transcranial magnetic stimulation (rTMS). Notably, the role of symptom severity in outcomes with rTMS is poorly understood. This study investigated the predictors of achieving remission in patients suffering from depression who receive ≥3 rTMS treatments per week. Available data on 41 patients treated at Walter Reed National Military Medical Center from 2009 to 2014 were included for analysis. Patients received a range of pulse sequences from 3,000 to 5,000 with left-sided or bilateral coil placement. Primary outcome measures were total score on the Patient Health Questionnaire-9 or the Quick Inventory of Depressive Symptomatology-Self Rated. Remission was defined as a total score less than five, and response was defined as a 50% decrease in the total score on both outcome metrics. Outcomes in patients diagnosed as suffering from mild or moderate depression were compared to those suffering from severe depression. Of the 41 patients receiving treatment, 16 reached remission and 18 reached response by the end of treatment. Remission rate was associated with the initial severity of depression, with patients with mild or moderate depression reaching remission at a significantly higher rate than those with severe depression. Total number of rTMS sessions or length of treatment was not predictors of remission. Patients with a baseline level of depression characterized as mild or moderate had significantly better outcomes following rTMS compared to patients with severe depression.

  13. Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain

    Directory of Open Access Journals (Sweden)

    Zhan-chi Zhang

    2015-01-01

    Full Text Available In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers, to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  14. Repetitive transcranial magnetic stimulation reduces cigarette consumption in schizophrenia patients.

    Science.gov (United States)

    Prikryl, Radovan; Ustohal, Libor; Kucerova, Hana Prikrylova; Kasparek, Tomas; Jarkovsky, Jiri; Hublova, Veronika; Vrzalova, Michaela; Ceskova, Eva

    2014-03-03

    High-frequency repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) seemed to decrease tobacco consumption and craving in nicotine-dependent people without psychiatric disorder or otherwise healthy people. Even if the prevalence of cigarette smoking in schizophrenia patients is high and estimated to be between 45% and 88%, this technique has not been systematically studied in this indication in schizophrenia yet. The aim of this study was to test the ability of high-frequency (10Hz) rTMS over the left DLPFC to decrease cigarette consumption in schizophrenia patients. The study included 35 male schizophrenia patients on stable antipsychotic medication. The patients were divided into two groups: the first (18 patients) were actively stimulated and the second (17 patients) underwent sham (placebo) stimulation. The sham rTMS was administered using a purpose-built sham coil that was identical in appearance to the real coil and made the same noise but did not deliver a substantial stimulus. The rTMS was administered at the stimulation parameters: location (left dorsolateral prefrontal cortex: DLPFC), intensity of magnetic stimulation in % of motor threshold (110%), stimulation frequency (10Hz), number of trains (20), single train duration (10s), inter-train interval (30s), and total number of stimulation sessions (21). In each stimulation session, 2000TMSpulses were given, with a total of 42,000pulses per treatment course. Patients noted the number of cigarettes smoked in the 7days before treatment, during the whole stimulation treatment (21days), and again for a 7-day period after treatment. Cigarette consumption was statistically significantly lower in the actively stimulated patients than in the sham rTMS group as early as the first week of stimulation. No statistically relevant correlations were found in the changes of ongoing negative or depressive schizophrenia symptoms and the number of cigarettes smoked. High

  15. [Effectiveness of transcranial magnetic therapy in the complex treatment of alcohol abstinent syndrome].

    Science.gov (United States)

    Staroverov, A T; Zhukov, O B; Raĭgorodskiĭ, Iu M

    2008-01-01

    Fifty-four abstinent alcohol-dependent patients have been studied. Twenty-nine patients (a main group) received, along with basic therapy, a physiotherapeutic treatment (transcranial dynamic magnetic therapy) and 25 patients (a control group) received only basic therapy. The comparison of the efficacy of treatment in patients of the main and control groups revealed the benefits of transcranial dynamic magnetic therapy in CNS function, performance on memory and attention tests, state of autonomic nervous system and psychoemotional state of patients (the reduction of anxiety and depression).

  16. Transcranial radiograph and magnetic resonance imaging in the evaluation of osseous changes of the temporomandibular joint

    International Nuclear Information System (INIS)

    Cho, Soo Beom; Koh, Kwang Joon

    2002-01-01

    To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

  17. Computational analysis of transcranial magnetic stimulation in the presence of deep brain stimulation probes

    Science.gov (United States)

    Syeda, F.; Holloway, K.; El-Gendy, A. A.; Hadimani, R. L.

    2017-05-01

    Transcranial Magnetic Stimulation is an emerging non-invasive treatment for depression, Parkinson's disease, and a variety of other neurological disorders. Many Parkinson's patients receive the treatment known as Deep Brain Stimulation, but often require additional therapy for speech and swallowing impairment. Transcranial Magnetic Stimulation has been explored as a possible treatment by stimulating the mouth motor area of the brain. We have calculated induced electric field, magnetic field, and temperature distributions in the brain using finite element analysis and anatomically realistic heterogeneous head models fitted with Deep Brain Stimulation leads. A Figure of 8 coil, current of 5000 A, and frequency of 2.5 kHz are used as simulation parameters. Results suggest that Deep Brain Stimulation leads cause surrounding tissues to experience slightly increased E-field (Δ Emax =30 V/m), but not exceeding the nominal values induced in brain tissue by Transcranial Magnetic Stimulation without leads (215 V/m). The maximum temperature in the brain tissues surrounding leads did not change significantly from the normal human body temperature of 37 °C. Therefore, we ascertain that Transcranial Magnetic Stimulation in the mouth motor area may stimulate brain tissue surrounding Deep Brain Stimulation leads, but will not cause tissue damage.

  18. Transcranial magnetic stimulation in Gilles de la Tourette syndrome.

    Science.gov (United States)

    Orth, Michael

    2009-12-01

    The cause of Gilles de la Tourette syndrome (GTS), a chronic motor and vocal tic disorder of childhood onset, remains unknown. Abnormalities in basal ganglia-thalamo-cortical circuits presumably play an important role in the pathophysiology underlying the involuntary tics. The use of transcranial magnetic stimulation (TMS), a noninvasive and painless tool to examine the excitability of several different circuits in the human motor cortex has advanced our understanding of the pathophysiology. Motor thresholds are similar in GTS and healthy subjects; in the resting state, recruitment of motor evoked potentials (MEPs) above threshold is more gradual in patients than controls. In contrast, recruitment of MEPs during preactivation is similar in both groups, as is the duration of the cortical silent period. This suggests that the distribution of excitability in the corticospinal system in patients at rest is different to that in healthy individuals. Importantly, correlation analysis showed that reduced levels of excitability at rest relate, in pure GTS patients, to video ratings of complex tics, and hand and finger tics, with less excitability predicting fewer tics. The correlations disappear for measures made during voluntary activation. This suggests that this is an adaptive response to abnormal basal ganglia-motor cortex inputs in an effort to reduce unwanted movements, a notion supported by electroencephalography-coherence studies that show increased cortico-cortical coupling. Compared to the healthy control group, short intracortical inhibition (SICI) thresholds are similar. However, above-threshold SICI recruitment and sensory afferent inhibition (SAI), a paradigm to examine sensory motor integration, are reduced in patients. This is consistent with the suggestion that reduced excitability of cortical inhibition is one factor that contributes to the difficulty that patients have in suppressing involuntary tics. In addition the reduced SAI indicates that impaired

  19. Transcranial Magnetic Stimulation and Connectivity Mapping: Tools for Studying the Neural Bases of Brain Disorders

    OpenAIRE

    Hampson, M.; Hoffman, R. E.

    2010-01-01

    There has been an increasing emphasis on characterizing pathophysiology underlying psychiatric and neurological disorders in terms of altered neural connectivity and network dynamics. Transcranial magnetic stimulation (TMS) provides a unique opportunity for investigating connectivity in the human brain. TMS allows researchers and clinicians to directly stimulate cortical regions accessible to electromagnetic coils positioned on the scalp. The induced activation can then propagate through...

  20. Low and High Frequency Repetitive Transcranial Magnetic Stimulation for the Treatment of Spasticity

    Science.gov (United States)

    Valle, Angela C.; Dionisio, Karen; Pitskel, Naomi Bass; Pascual-Leone, Alvaro; Orsati, Fernanda; Ferreira, Merari J. L.; Boggio, Paulo S.; Lima, Moises C.; Rigonatti, Sergio P.; Fregni, Felipe

    2007-01-01

    The development of non-invasive techniques of cortical stimulation, such as transcranial magnetic stimulation (TMS), has opened new potential avenues for the treatment of neuropsychiatric diseases. We hypothesized that an increase in the activity in the motor cortex by cortical stimulation would increase its inhibitory influence on spinal…

  1. Repetitive transcranial magnetic stimulation to improve mood and motor function in Parkinson's disease.

    NARCIS (Netherlands)

    Helmich, R.C.G.; Siebner, H.R.; Bakker, M.; Munchau, A.; Bloem, B.R.

    2006-01-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that can produce lasting changes in excitability and activity in cortical regions underneath the stimulation coil (local effect), but also within functionally connected cortical or subcortical regions

  2. Repetitive Transcranial Magnetic Stimulation to the Primary Motor Cortex Interferes with Motor Learning by Observing

    Science.gov (United States)

    Brown, Liana E.; Wilson, Elizabeth T.; Gribble, Paul L.

    2009-01-01

    Neural representations of novel motor skills can be acquired through visual observation. We used repetitive transcranial magnetic stimulation (rTMS) to test the idea that this "motor learning by observing" is based on engagement of neural processes for learning in the primary motor cortex (M1). Human subjects who observed another person learning…

  3. Accelerated high-frequency repetitive transcranial magnetic stimulation enhances motor activity in rats

    NARCIS (Netherlands)

    El Arfani, Anissa; Parthoens, Joke; Demuyser, Thomas; Servaes, Stijn; De Coninck, Mattias; De Deyn, Peter Paul; Van Dam, Debby; Wyckhuys, Tine; Baeken, Chris; Smolders, Ilse; Staelens, Steven

    2017-01-01

    High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) is currently accepted as an evidence-based treatment option for treatment-resistant depression (TRD). Additionally, HF-rTMS showed beneficial effects on psychomotor retardation in patients. The classical HF-rTMS paradigms however

  4. Transcranial magnetic stimulation-induced 'visual echoes' are generated in early visual cortex

    NARCIS (Netherlands)

    Jolij, Jacob; Lamme, Victor A. F.

    2010-01-01

    Transcranial magnetic stimulation (TMS) of the early visual areas can trigger perception of a flash of light, a so-called phosphene. Here we show that a very brief presentation of a stimulus can modulate features of a subsequent TMS-induced phosphene, to a level that participants mistake phosphenes

  5. Functional Assessment of Corticospinal Conduction with Transcranial Magnetic Stimulation: Basic Principles

    DEFF Research Database (Denmark)

    Groppa, S.; Peller, M.; Siebner, Hartwig R.

    2010-01-01

    Here we review how transcranial magnetic stimulation (TMS) is used in clinical practice to examine the functional integrity of the fast conducting fibres of the human corticomotor path ways. We first summarise the technical and physiological principles of TMS that are relevant to its clinical use...

  6. Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

    Science.gov (United States)

    Moloney, Tonya M; Witney, Alice G

    2014-01-01

    The primary motor cortex (M1) is an effective target of non-invasive cortical stimulation (NICS) for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. Here we investigate whether transcranial direct current stimulation (tDCS) primed 1 Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs) from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST) through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (ppain thresholds (ppain. This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

  7. A comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia

    NARCIS (Netherlands)

    Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Koelman, J. H.; Ongerboer de Visser, B. W.

    1999-01-01

    Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was

  8. Reflecting on mirror mechanisms: motor resonance effects during action observation only present with low-intensity transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Michela Loporto

    Full Text Available Transcranial magnetic stimulation (TMS studies indicate that the observation of other people's actions influences the excitability of the observer's motor system. Motor evoked potential (MEP amplitudes typically increase in muscles which would be active during the execution of the observed action. This 'motor resonance' effect is thought to result from activity in mirror neuron regions, which enhance the excitability of the primary motor cortex (M1 via cortico-cortical pathways. The importance of TMS intensity has not yet been recognised in this area of research. Low-intensity TMS predominately activates corticospinal neurons indirectly, whereas high-intensity TMS can directly activate corticospinal axons. This indicates that motor resonance effects should be more prominent when using low-intensity TMS. A related issue is that TMS is typically applied over a single optimal scalp position (OSP to simultaneously elicit MEPs from several muscles. Whether this confounds results, due to differences in the manner that TMS activates spatially separate cortical representations, has not yet been explored. In the current study, MEP amplitudes, resulting from single-pulse TMS applied over M1, were recorded from the first dorsal interosseous (FDI and abductor digiti minimi (ADM muscles during the observation of simple finger abductions. We tested if the TMS intensity (110% vs. 130% resting motor threshold or stimulating position (FDI-OSP vs. ADM-OSP influenced the magnitude of the motor resonance effects. Results showed that the MEP facilitation recorded in the FDI muscle during the observation of index-finger abductions was only detected using low-intensity TMS. In contrast, changes in the OSP had a negligible effect on the presence of motor resonance effects in either the FDI or ADM muscles. These findings support the hypothesis that MN activity enhances M1 excitability via cortico-cortical pathways and highlight a methodological framework by which the

  9. 3D realistic head model simulation based on transcranial magnetic stimulation.

    Science.gov (United States)

    Yang, Shuo; Xu, Guizhi; Wang, Lei; Chen, Yong; Wu, Huanli; Li, Ying; Yang, Qingxin

    2006-01-01

    Transcranial magnetic stimulation (TMS) is a powerful non-invasive tool for investigating functions in the brain. The target inside the head is stimulated with eddy currents induced in the tissue by the time-varying magnetic field. Precise spatial localization of stimulation sites is the key of efficient functional magnetic stimulations. Many researchers devote to magnetic field analysis in empty free space. In this paper, a realistic head model used in Finite Element Method has been developed. The magnetic field inducted in the head bt TMS has been analysed. This three-dimensional simulation is useful for spatial localization of stimulation.

  10. The safety of transcranial magnetic stimulation with deep brain stimulation instruments

    OpenAIRE

    Shimojima, Yoshio; Morita, Hiroshi; Nishikawa, Noriko; Kodaira, Minori; Hashimoto, Takao; Ikeda, Shu-ichi

    2010-01-01

    Objectives: Transcranial magnetic stimulation (TMS) has been employed in patients with an implanted deep brain Stimulation (DBS) device. We investigated the safety of TMS using Simulation models with an implanted DBS device. Methods: The DBS lead was inserted into plastic phantoms filled with dilute gelatin showing impedance similar to that of human brain. TMS was performed with three different types of magnetic coil. During TMS (I) electrode movement, (2) temperature change around the lead, ...

  11. Cortico-cortical and motor evoked potentials to single and paired-pulse stimuli: An exploratory transcranial magnetic and intracranial electric brain stimulation study.

    Science.gov (United States)

    Boulogne, Sébastien; Andre-Obadia, Nathalie; Kimiskidis, Vasilios K; Ryvlin, Philippe; Rheims, Sylvain

    2016-11-01

    Paired-pulse (PP) paradigms are commonly employed to assess in vivo cortical excitability using transcranial magnetic stimulation (TMS) to stimulate the primary motor cortex and modulate the induced motor evoked potential (MEP). Single-pulse cortical direct electrical stimulation (DES) during intracerebral EEG monitoring allows the investigation of brain connectivity by eliciting cortico-cortical evoked potentials (CCEPs). However, PP paradigm using intracerebral DES has rarely been reported and has never been previously compared with TMS. The work was intended (i) to verify that the well-established modulations of MEPs following PP TMS remain similar using DES in the motor cortex, and (ii) to evaluate if a similar pattern could be observed in distant cortico-cortical connections through modulations of CCEP. Three patients undergoing intracerebral EEG monitoring with electrodes implanted in the central region were studied. Single-pulse DES (1-3 mA, 1 ms, 0.2 Hz) and PP DES using six interstimulus intervals (5, 15, 30, 50, 100, and 200 ms) in the motor cortex with concomitant recording of CCEPs and MEPs in contralateral muscles were performed. Finally, a navigated PP TMS session targeted the intracranial stimulation site to record TMS-induced MEPs in two patients. MEP modulations elicited by PP intracerebral DES proved similar among the three patients and to those obtained by PP TMS. CCEP modulations elicited by PP intracerebral DES usually showed a pattern comparable to that of MEP, although a different pattern could be observed occasionally. PP intracerebral DES seems to involve excitatory and inhibitory mechanisms similar to PP TMS and allows the recording of intracortical inhibition and facilitation modulation on cortico-cortical connections. Hum Brain Mapp 37:3767-3778, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. The effects of combined repetitive transcranial magnetic stimulation and transcranial direct current stimulation on motor function in patients with stroke.

    Science.gov (United States)

    Kwon, Tae Gun; Park, Eunhee; Kang, Chung; Chang, Won Hyuk; Kim, Yun-Hee

    2016-11-22

    Both transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), when provided to stroke patients in combination with motor training, enhance therapeutic efficacy and motor function. However, the majority of previous studies have only examined a single treatment modality. The authors investigated the modulating influence of combination dual-mode brain stimulation upon bihemispheric stimulation with motor training in stroke patients. Twenty stroke patients with hemiparesis underwent five randomly arranged sessions of diverse combinations of rTMS and tDCS. We applied cathodal or anodal tDCS over the contralesional primary motor cortex (cM1) and 10 Hz rTMS over the ipsilesional primary motor cortex (iM1) in a simultaneous or preconditioning method including sham stimulation. Immediately after dual-mode stimulation, sequential hand motor training was performed for 5 minutes. The total pulses of rTMS and the duration of tDCS and motor training were the same for all sessions. Cortical excitability and sequential motor performance were evaluated before and after each session. Motor function and corticomotor excitability following simultaneous stimulation via cathodal tDCS over the cM1 combined with 10 Hz rTMS over the iM1 were significantly increased after the intervention, with significantly greater motor improvement than seen with other treatment conditions (P motor performance in stroke patients than other combination methods. This result seemed to be related to effective modulation of interhemispheric imbalance of cortical excitability by dual-mode stimulation.

  13. Pressure pain thresholds increase after preconditioning 1 Hz repetitive transcranial magnetic stimulation with transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Tonya M Moloney

    Full Text Available BACKGROUND: The primary motor cortex (M1 is an effective target of non-invasive cortical stimulation (NICS for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. OBJECTIVE: Here we investigate whether transcranial direct current stimulation (tDCS primed 1 Hz repetitive transcranial magnetic stimulation (rTMS modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. METHOD: 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. RESULTS: Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (p<0.001 with a parallel increase in pressure pain thresholds (p<0.01. In contrast, anodal tDCS-primed 1 Hz-rTMS resulted in a corresponding decrease in cortical excitability (p<0.05, with no significant effect on pressure pain. CONCLUSION: This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.

  14. Using transcranial magnetic stimulation of the undamaged brain to identify lesion sites that predict language outcome after stroke.

    Science.gov (United States)

    Lorca-Puls, Diego L; Gajardo-Vidal, Andrea; Seghier, Mohamed L; Leff, Alexander P; Sethi, Varun; Prejawa, Susan; Hope, Thomas M H; Devlin, Joseph T; Price, Cathy J

    2017-06-01

    Transcranial magnetic stimulation focused on either the left anterior supramarginal gyrus or opercular part of the left inferior frontal gyrus has been reported to transiently impair the ability to perform phonological more than semantic tasks. Here we tested whether phonological processing abilities were also impaired following lesions to these regions in right-handed, English speaking adults, who were investigated at least 1 year after a left-hemisphere stroke. When our regions of interest were limited to 0.5 cm3 of grey matter centred around sites that had been identified with transcranial magnetic stimulation-based functional localization, phonological impairments were observed in 74% (40/54) of patients with damage to the regions and 21% (21/100) of patients sparing these regions. This classification accuracy was better than that observed when using regions of interest centred on activation sites in previous functional magnetic resonance imaging studies of phonological processing, or transcranial magnetic stimulation sites that did not use functional localization. New regions of interest were generated by redefining the borders of each of the transcranial magnetic stimulation sites to include areas that were consistently damaged in the patients with phonological impairments. This increased the incidence of phonological impairments in the presence of damage to 85% (46/54) and also reduced the incidence of phonological impairments in the absence of damage to 15% (15/100). The difference in phonological processing abilities between those with and without damage to these 'transcranial magnetic stimulation-guided' regions remained highly significant even after controlling for the effect of lesion size. The classification accuracy of the transcranial magnetic stimulation-guided regions was validated in a second sample of 108 patients and found to be better than that for (i) functional magnetic resonance imaging-guided regions; (ii) a region identified from an

  15. Study of intracranial pressure in human brain during transcranial magnetic stimulation.

    Science.gov (United States)

    Honrath, Marc; Sabouni, Abas

    2015-01-01

    This paper presents the results of cranial force in human brain due to electromagnetic pulse during transcranial magnetic stimulation. To model the force in a realistic brain, we used three dimensional magnetic resonance image of the 26 years old female subject. Simulation results show that during TMS procedure, there is a small force generated within the cranial tissue layers along with a torque value in different layers of brain tissues. The force depends on the magnitude of the magnetic field generated by the TMS coil.

  16. Calculating the electric field in real human head by transcranial magnetic stimulation with shield plate

    Science.gov (United States)

    Lu, Mai; Ueno, Shoogo

    2009-04-01

    In this paper, we present a transcranial magnetic stimulation (TMS) system by incorporating a conductive shield plate. The magnetic field, induced current density, and electric field in a real human head were calculated by impedance method and the results were compared with TMS without shielding. Our results show that the field localization can be improved by introducing a conductive shield plate; the stimulation magnitude (depth) in the brain is reduced comparing with the TMS without shielding. The strong magnetic field near the TMS coil is difficult to be efficiently shielded by a thinner conductive shield plate.

  17. Investigative and therapeutic uses of Transcranial magnetic stimulation (TMS) in Attention Deficit Hyperactivity Disorder (ADHD).

    Science.gov (United States)

    Zaman, Rashid

    2016-09-01

    Attention Deficit Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder that affects children and young adults. It results in significant impairment of their educational, social and occupational functioning and is associated economic societal burden. Whilst there are effective medications (such as methylphenidate) as well as some psychobehavioural therapies that can help with management of symptoms of ADHD, the former can have significant cardiac side effects, which limit their use. For number of patients these treatment options lack efficacy or are not acceptable. There is need to improve our understanding of neurobiology of ADHD as well as explore other treatment options. Transcranial magnetic stimulation (TMS) and repetitive transcranial magnetic stimulation (rTMS) are safe and non-invasive investigative and therapeutic tools respectively. In this short paper, I will explore the potential role of TMS and rTMS in further improving our understanding of the neurobiology of ADHD as well as possible treatment option.

  18. Successful use of transcranial magnetic stimulation in difficult to treat hypersexual disorder

    Directory of Open Access Journals (Sweden)

    Adarsh Tripathi

    2016-01-01

    Full Text Available Hypersexual disorder has phenomenological resemblance with impulsive-compulsive spectrum disorders. Inhibitory repetitive transcranial magnetic stimulation (rTMS over the supplementary motor area (SMA has been found to be effective in the management of impulsive-compulsive behaviors. Inhibitory rTMS over SMA may be helpful in hypersexual disorder. We highlight here a case of hypersexual disorder (excessive sexual drive who failed to respond adequately to the conventional pharmacological treatment and responded with rTMS augmentation.

  19. Enhancing Warfighter Cognitive Abilities with Transcranial Magnetic Stimulation: A Feasibility Analysis

    Science.gov (United States)

    2007-06-01

    Abilities with Transcranial N/A Magnetic Stimulation: a Feasibility Analysis 5b. GRANTNUMBER N/A 5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S) 5d...has been found to play a part in impulse control, judgment, language production, working memory, motor function, problem-solving, sexual behavior...music. Most often, but not always, savant syndrome is found in individuals with autism . And, unfortunately, savants typically are not able to explain

  20. Extracting Visual Evoked Potentials from EEG Data Recorded During fMRI-guided Transcranial Magnetic Stimulation

    OpenAIRE

    Sadeh, Boaz; Yovel, Galit

    2014-01-01

    Transcranial Magnetic Stimulation (TMS) is an effective method for establishing a causal link between a cortical area and cognitive/neurophysiological effects. Specifically, by creating a transient interference with the normal activity of a target region and measuring changes in an electrophysiological signal, we can establish a causal link between the stimulated brain area or network and the electrophysiological signal that we record. If target brain areas are functionally defined with prior...

  1. Simultaneous transcranial magnetic stimulation and single neuron recording in alert non-human primates

    OpenAIRE

    Mueller, Jerel K.; Grigsby, Erinn M.; Prevosto, Vincent; Petraglia, Frank W.; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V.; Sommer, Marc A.; Egner, Tobias; Platt, Michael L.; Grill, Warren M.

    2014-01-01

    Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report novel methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally per...

  2. Tibialis anterior stretch reflex in early stance is suppressed by repetitive transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Zuur, Abraham T; Christensen, Mark Schram; Sinkjær, Thomas

    2009-01-01

    Abstract A rapid plantar flexion perturbation in the early stance phase of walking elicits a large stretch reflex in tibialis anterior (TA). In this study we use repetitive Transcranial Magnetic Stimulation (rTMS) to test if this response is mediated through a transcortical pathway. TA stretch...... reflexes were elicited in the early stance phase of the step cycle during treadmill walking. 20 minutes of 1 Hz rTMS at 115% resting motor threshold (MTr) significantly decreased (p

  3. [Study of the facial nerve motor pathway with the transcranial cerebral magnetic stimulation technique].

    Science.gov (United States)

    Barona, R; Escudero, J; López-Trigo, J; Escudero, M; Armengot, M

    1992-01-01

    Transcranial magnetic stimulation method permits the study of the facial nerve in all its aspects (motor cortex-alpha moto-neurone-facial muscle) in an non invasive and painless way. We studied 12 patients using two levels of stimuli, the first was at an occipital level and the second at the primary motor cortex in the frontal lobe. We compared the results of this technique with those obtained by electric stimulation of the nerve.

  4. Effect of anatomical variability in brain on transcranial magnetic stimulation treatment

    Science.gov (United States)

    Syeda, F.; Magsood, H.; Lee, E. G.; El-Gendy, A. A.; Jiles, D. C.; Hadimani, R. L.

    2017-05-01

    Transcranial Magnetic Stimulation is a non-invasive clinical therapy used to treat depression and migraine, and shows further promise as treatment for Parkinson's disease, Alzheimer's disease, and other neurological disorders. However, it is yet unclear as to how anatomical differences may affect stimulation from this treatment. We use finite element analysis to model and analyze the results of Transcranial Magnetic Stimulation in various head models. A number of heterogeneous head models have been developed using MRI data of real patients, including healthy individuals as well as patients of Parkinson's disease. Simulations of Transcranial Magnetic Stimulation performed on 22 anatomically different models highlight the differences in induced stimulation. A standard Figure of 8 coil is used with frequency 2.5 kHz, placed 5 mm above the head. We compare cortical stimulation, volume of brain tissue stimulated, specificity, and maximum E-field induced in the brain for models ranging from ages 20 to 60. Results show that stimulation varies drastically between patients of the same age and health status depending upon brain-scalp distance, which is not necessarily a linear progression with age.

  5. Transcranial magnetic stimulation probes the excitability of the primary motor cortex: A framework to account for the facilitating effects of acute whole-body exercise on motor processes

    Directory of Open Access Journals (Sweden)

    Karen Davranche

    2015-03-01

    Full Text Available The effects of exercise on decision-making performance have been studied using a wide variety of cognitive tasks and exercise interventions. Although the current literature supports a beneficial influence of acute exercise on cognitive performance, the mechanisms underlying this phenomenon have not yet been elucidated. We review studies that used single-pulse transcranial magnetic stimulation (TMS to probe the excitability of motor structures during whole-body exercise and present a framework to account for the facilitating effects of acute exercise on motor processes. Recent results suggest that, even in the absence of fatigue, the increase in corticospinal excitability classically reported during submaximal and exhausting exercises may be accompanied by a reduction in intracortical inhibition. We propose that reduced intracortical inhibition elicits an adaptive central mechanism that counteracts the progressive reduction in muscle responsiveness caused by peripheral fatigue. Such a reduction would render the motor cortex more sensitive to upstream influences, thus causing increased corticospinal excitability. Furthermore, reduction of intracortical inhibition may account for the more efficient descending drive and for the improvement of reaction time performance during exercise. The adaptive modulation in intracortical inhibition could be implemented through a general increase in reticular activation that would further account for enhanced sensory sensitivity.

  6. Transcranial Magnetic Stimulation (TMS) as a Tool for Early Diagnosis and Prognostication in Cortico-Basal Ganglia Degeneration (CBD) Syndromes: Review of Literature and Case Report.

    Science.gov (United States)

    Issac, Thomas Gregor; Chandra, Sadanandavalli Retnaswami; Nagaraju, B C

    2016-01-01

    Cortico basal degeneration (CBD) of the brain is a rare progressive neurodegenerative disease which encompasses unique neuropsychiatric manifestations. Early diagnosis is essential for initiating proper treatment and favorable outcome. Transcranial Magnetic Stimulation (TMS), a well-known technique for assessment of cortical excitatory and inhibitory properties. It was suggested that in a degenerative disease like CBD which involves the cortex as well as the subcortical structures, comparing both hemispheres, a differential pattern in TMS can be obtained which would help in early identification, prognostication and early therapeutic intervention. We describe a case of CBD with corroborative clinical and imaging picture wherein single pulse TMS was used over both the hemispheres measuring the following parameters of interest which included: Motor Threshold (MT), Central Motor Conduction Time (CMCT) and Silent Period (SP). Differential patterns of MT, CMCT and SP was obtained by stimulating over both the hemispheres with the affected hemisphere showing significantly reduced MT and prolonged CMCT implying early impairment of cortical and subcortical structures thereby revealing the potential application of TMS being utilized in a novel way for early detection and prognostication in CBD syndromes.

  7. Efficiency test of filtering methods for the removal of transcranial magnetic stimulation artifacts on human electroencephalography with artificially transcranial magnetic stimulation-corrupted signals

    Science.gov (United States)

    Zilber, Nicolas A.; Katayama, Yoshinori; Iramina, Keiji; Erich, Wintermantel

    2010-05-01

    A new approach is proposed to test the efficiency of methods, such as the Kalman filter and the independent component analysis (ICA), when applied to remove the artifacts induced by transcranial magnetic stimulation (TMS) from electroencephalography (EEG). By using EEG recordings corrupted by TMS induction, the shape of the artifacts is approximately described with a model based on an equivalent circuit simulation. These modeled artifacts are subsequently added to other EEG signals—this time not influenced by TMS. The resulting signals prove of interest since we also know their form without the pseudo-TMS artifacts. Therefore, they enable us to use a fit test to compare the signals we obtain after removing the artifacts with the original signals. This efficiency test turned out very useful in comparing the methods between them, as well as in determining the parameters of the filtering that give satisfactory results with the automatic ICA.

  8. Combined use of transcranial magnetic stimulation and metal electrode implants: a theoretical assessment of safety considerations

    Science.gov (United States)

    Golestanirad, Laleh; Rouhani, Hossein; Elahi, Behzad; Shahim, Kamal; Chen, Robert; Mosig, Juan R.; Pollo, Claudio; Graham, Simon J.

    2012-12-01

    This paper provides a theoretical assessment of the safety considerations encountered in the simultaneous use of transcranial magnetic stimulation (TMS) and neurological interventions involving implanted metallic electrodes, such as electrocorticography. Metal implants are subject to magnetic forces due to fast alternating magnetic fields produced by the TMS coil. The question of whether the mechanical movement of the implants leads to irreversible damage of brain tissue is addressed by an electromagnetic simulation which quantifies the magnitude of imposed magnetic forces. The assessment is followed by a careful mechanical analysis determining the maximum tolerable force which does not cause irreversible tissue damage. Results of this investigation provide useful information on the range of TMS stimulator output powers which can be safely used in patients having metallic implants. It is shown that conventional TMS applications can be considered safe when applied on patients with typical electrode implants as the induced stress in the brain tissue remains well below the limit of tissue damage.

  9. No modulatory effects by transcranial static magnetic field stimulation of human motor and somatosensory cortex.

    Science.gov (United States)

    Kufner, Marco; Brückner, Sabrina; Kammer, Thomas

    Recently, it was reported that the application of a static magnetic field by placing a strong permanent magnet over the scalp for 10 min led to an inhibition of motor cortex excitability for at least 6 min after removing the magnet. When placing the magnet over the somatosensory cortex, a similar inhibitory after effect could be observed as well. Our aim was to replicate the inhibitory effects of transcranial static magnetic field stimulation in the motor and somatosensory system. The modulatory effect of static magnetic field stimulation was investigated in three experiments. In two experiments motor cortex excitability was measured before and after 10 or 15 min of magnet application, respectively. The second experiment included a sham condition and was designed in a double-blinded manner. In a third experiment, paired-pulse SSEPs were measured pre and four times post positioning the magnet over the somatosensory cortex for 10 min on both hemispheres, respectively. The SSEPs of the non stimulated hemisphere served as control condition. We did not observe any systematic effect of the static magnetic field neither on motor cortex excitability nor on SSEPs. Moreover, no SSEP paired-pulse suppression was found. We provide a detailed analysis of possible confounding factors and differences to previous studies on tSMS. After all, our results could not confirm the static magnetic field effect. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  10. Transcranial magnetic stimulation of the brain: guidelines for pain treatment research.

    Science.gov (United States)

    Klein, Max M; Treister, Roi; Raij, Tommi; Pascual-Leone, Alvaro; Park, Lawrence; Nurmikko, Turo; Lenz, Fred; Lefaucheur, Jean-Pascal; Lang, Magdalena; Hallett, Mark; Fox, Michael; Cudkowicz, Merit; Costello, Ann; Carr, Daniel B; Ayache, Samar S; Oaklander, Anne Louise

    2015-09-01

    Recognizing that electrically stimulating the motor cortex could relieve chronic pain sparked development of noninvasive technologies. In transcranial magnetic stimulation (TMS), electromagnetic coils held against the scalp influence underlying cortical firing. Multiday repetitive transcranial magnetic stimulation (rTMS) can induce long-lasting, potentially therapeutic brain plasticity. Nearby ferromagnetic or electronic implants are contraindications. Adverse effects are minimal, primarily headaches. Single provoked seizures are very rare. Transcranial magnetic stimulation devices are marketed for depression and migraine in the United States and for various indications elsewhere. Although multiple studies report that high-frequency rTMS of the motor cortex reduces neuropathic pain, their quality has been insufficient to support Food and Drug Administration application. Harvard's Radcliffe Institute therefore sponsored a workshop to solicit advice from experts in TMS, pain research, and clinical trials. They recommended that researchers standardize and document all TMS parameters and improve strategies for sham and double blinding. Subjects should have common well-characterized pain conditions amenable to motor cortex rTMS and studies should be adequately powered. They recommended standardized assessment tools (eg, NIH's PROMIS) plus validated condition-specific instruments and consensus-recommended metrics (eg, IMMPACT). Outcomes should include pain intensity and qualities, patient and clinician impression of change, and proportions achieving 30% and 50% pain relief. Secondary outcomes could include function, mood, sleep, and/or quality of life. Minimum required elements include sample sources, sizes, and demographics, recruitment methods, inclusion and exclusion criteria, baseline and posttreatment means and SD, adverse effects, safety concerns, discontinuations, and medication-usage records. Outcomes should be monitored for at least 3 months after initiation

  11. Focal hand dystonia: individualized intervention with repeated application of repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Kimberley, Teresa Jacobson; Borich, Michael R; Schmidt, Rebekah L; Carey, James R; Gillick, Bernadette

    2015-04-01

    To examine for individual factors that may predict response to inhibitory repetitive transcranial magnetic stimulation (rTMS) in focal hand dystonia (FHD); to present the method for determining optimal stimulation to increase inhibition in a given patient; and to examine individual responses to prolonged intervention. Single-subject design to determine optimal parameters to increase inhibition for a given subject and to use the selected parameters once per week for 6 weeks, with 1-week follow-up, to determine response. Clinical research laboratory. A volunteer sample of subjects with FHD (N = 2). One participant had transcranial magnetic stimulation responses indicating impaired inhibition, and the other had responses within normative limits. There were 1200 pulses of 1-Hz rTMS delivered using 4 different stimulation sites/intensity combinations: primary motor cortex at 90% or 110% of resting motor threshold (RMT) and dorsal premotor cortex (PMd) at 90% or 110% of RMT. The parameters producing the greatest within-session increase in cortical silent period (CSP) duration were then used as the intervention. Response variables included handwriting pressure and velocity, subjective symptom rating, CSP, and short latency intracortical inhibition and facilitation. The individual with baseline transcranial magnetic stimulation responses indicating impaired inhibition responded favorably to the repeated intervention, with reduced handwriting force, an increase in the CSP, and subjective report of moderate symptom improvement at 1-week follow-up. The individual with normative baseline responses failed to respond to the intervention. In both subjects, 90% of RMT to the PMd produced the greatest lengthening of the CSP and was used as the intervention. An individualized understanding of neurophysiological measures can be an indicator of responsiveness to inhibitory rTMS in focal dystonia, with further work needed to determine likely responders versus nonresponders. Copyright

  12. Repetitive Transcranial Magnetic Stimulation for Wernicke-Korsakoff Syndrome: A Case Report.

    Science.gov (United States)

    Chung, So Won; Park, Shin Who; Seo, Young Jae; Kim, Jae-Hyung; Lee, Chan Ho; Lim, Jong Youb

    2017-02-01

    A 57-year-old man who was diagnosed with Wernicke-Korsakoff syndrome showed severe impairment of cognitive function and a craving for alcohol, even after sufficient supplementation with thiamine. After completing 10 sessions of 10 Hz repetitive transcranial magnetic stimulation (rTMS) at 100% of the resting motor threshold over the left dorsolateral prefrontal cortex, dramatic improvement in cognitive function and a reduction in craving for alcohol were noted. This is the first case report of the efficacy of a high-frequency rTMS in the treatment of Wernicke-Korsakoff syndrome.

  13. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...... a reduced intensity of this pulse would lead to significant changes as has been reported for hand muscles using a monophasic TMS pulse. Three interventions were investigated: (1) suprathreshold PAbi-PAS (n = 11); (2) suprathreshold PAmono-PAS (n = 11) where PAS was applied using a biphasic or monophasic...

  14. Origin of the low-level EMG during the silent period following transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Butler, Jane E; Petersen, Nicolas C; Herbert, Robert D

    2012-01-01

    OBJECTIVE: The cortical silent period refers to a period of near silence in the electromyogram (EMG) after transcranial magnetic stimulation (TMS) of the motor cortex during contraction. However, low-level EMG of unknown origin is often present. We hypothesised that it arises through spinal...... the motor cortex. The rate of flexion during shortening contractions reduced muscle lengthening caused by muscle relaxation. Surface EMG was recorded from biceps brachii and brachioradialis, and the low-level EMG during silent periods produced by TMS was measured. RESULTS: Low-level EMG activity was reduced...

  15. Multiple sessions of low-frequency repetitive transcranial magnetic stimulation in focal hand dystonia

    DEFF Research Database (Denmark)

    Kimberley, Teresa Jacobson; Borich, Michael R; Arora, Sanjeev

    2013-01-01

    Purpose: The ability of low-frequency repetitive transcranial magnetic stimulation (rTMS) to enhance intracortical inhibition has motivated its use as a potential therapeutic intervention in focal hand dystonia (FHD). In this preliminary investigation, we assessed the physiologic and behavioral...... effects of multiple sessions of rTMS in FHD. Methods: 12 patients with FHD underwent five daily-sessions of 1 Hz rTMS to contralateral dorsal premotor cortex (dPMC). Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. We hypothesized that an active but non...

  16. Transcranial magnetic stimulation of right inferior parietal cortex causally influences prefrontal activation for visual detection

    DEFF Research Database (Denmark)

    Leitao, Joana; Thielscher, Axel; Lee, Hweeling

    2017-01-01

    -parietal areas integrating the evidence into a decision variable that is compared to a decisional threshold. This concurrent transcranial magnetic stimulation (TMS)-fMRI study applied 10 Hz bursts of four TMS (or Sham) pulses to the intraparietal sulcus (IPS) to investigate the causal influence of IPS...... on the neural systems involved in perceptual decision-making. Participants had to detect visual signals at threshold intensity that were presented in their left lower visual field on 50% of the trials. Critically, we adjusted the signal strength such that participants failed to detect the visual stimulus...

  17. BRAIN initiative: transcranial magnetic stimulation automation and calibration.

    Science.gov (United States)

    Todd, Garth D; Abdellatif, Ahmed; Sabouni, Abas

    2014-01-01

    In this paper, we introduced an automated TMS system with robot control and optical sensor combined with neuronavigation software. By using the robot, the TMS coil can be accurately positioned over any preselected brain region. The neuronavigation system provides an accurate positioning of a magnetic coil in order to induce a specific cortical excitation. An infrared optical measurement device is also used in order to detect and compensate for head movements of the patient. This procedure was simulated using a PC based robotic simulation program. The proposed automated robot system is integrated with TMS numerical solver and allows users to actually see the depth, location, and shape of the induced eddy current on the computer monitor.

  18. Transcranial magnetic stimulation as an antidepressant alternative in a patient with Brugada syndrome and recurrent syncope.

    Science.gov (United States)

    Alampay, Miguel M; Haigney, Mark C; Flanagan, Michael C; Perito, Robert M; Love, Kathleen M; Grammer, Geoffrey G

    2014-11-01

    Brugada syndrome (BrS) is a common occult cause of sudden cardiac arrest in otherwise healthy-appearing adults. The pathognomonic electrocardiographic pattern may be unmasked only by certain medications, many of which are unknown. We report a case of a depressed but otherwise healthy man with an asymptomatic right bundle branch block on electrocardiography who experienced antidepressant-induced BrS and ultimately recovered with transcranial magnetic stimulation (TMS). After an initial trial of nortriptyline, the patient's depressive symptoms improved; however, he experienced a syncopal event and was subsequently diagnosed as having BrS. Cross titration to bupropion, which had not previously been known to exacerbate BrS, was followed by another cardiac event. As a result, the patient was referred for TMS as a substitute for pharmacotherapy. After 31 TMS sessions over 8 weeks, the patient demonstrated significant improvement by subjective report and objective reduction in his Patient Health Questionnaire-9 scores from 10 (moderate) to 1 (minimal). Transcranial magnetic stimulation is a Food and Drug Administration-approved nonpharmacologic treatment for depression. Given the potential lethality of BrS with known and unknown psychopharmacologic agents, providers should consider TMS as first-line therapy in this patient population. Bupropion should be added to the list of agents known to exacerbate this disease. Copyright © 2014 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  19. Cerebellar transcranial static magnetic field stimulation transiently reduces cerebellar brain inhibition.

    Science.gov (United States)

    Matsugi, Akiyoshi; Okada, Y

    The aim of this study was to investigate whether transcranial static magnetic field stimulation (tSMS) delivered using a compact cylindrical NdFeB magnet over the cerebellum modulates the excitability of the cerebellum and contralateral primary motor cortex, as measured using cerebellar brain inhibition (CBI), motor evoked potentials (MEPs), and resting motor threshold (rMT). These parameters were measured before tSMS or sham stimulation and immediately, 5 minutes and 10 minutes after stimulation. There were no significant changes in CBI, MEPs or rMT over time in the sham stimulation condition, and no changes in MEPs or rMT in the tSMS condition. However, CBI was significantly decreased immediately after tSMS as compared to that before and 5 minutes after tSMS. Our results suggest that tSMS delivered to the cerebellar hemisphere transiently reduces cerebellar inhibitory output but does not affect the excitability of the contralateral motor cortex.

  20. Safety Study of Transcranial Static Magnetic Field Stimulation (tSMS) of the Human Cortex.

    Science.gov (United States)

    Oliviero, A; Carrasco-López, M C; Campolo, M; Perez-Borrego, Y A; Soto-León, V; Gonzalez-Rosa, J J; Higuero, A M; Strange, B A; Abad-Rodriguez, J; Foffani, G

    2015-01-01

    Transcranial static magnetic field stimulation (tSMS) in humans reduces cortical excitability. The objective of this study was to determine if prolonged tSMS (2 h) could be delivered safely in humans. Safety limits for this technique have not been described. tSMS was applied for 2 h with a cylindric magnet on the occiput of 17 healthy subjects. We assessed tSMS-related safety aspects at tissue level by measuring levels of neuron-specific enolase (NSE, a marker of neuronal damage) and S100 (a marker of glial reactivity and damage). We also included an evaluation of cognitive side effects by using a battery of visuomotor and cognitive tests. tSMS did not induce any significant increase in NSE or S100. No cognitive alteration was detected. Our data indicate that the application of tSMS is safe in healthy human subjects, at least within these parameters. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. [Transcranial magnetic therapy in the treatment of psychoautonomous disturbances in children with diabetes mellitus type 1].

    Science.gov (United States)

    Filina, N Iu; Bolotova, N V; Manukian, V Iu; Nikolaeva, N V; Kompaniets, O V

    2009-01-01

    Results of a clinical-physiological study of 80 children with diabetes mellitus type 1 with psychoautonomous disturbances are presented. Forty patients of the main group received transcranial magnetic therapy (TcMT), 40 patients of the control group had placebo sessions of TcMT with magnetic power supply switched off. TcMT was applied using bitemporal method, running regime with modulation frequency 1-10 Hz. Patients received 10 sessions. Positive changes were found in the main group compared to the controls. In the main group, TcMT sessions allowed to normalize the autonomous status in 75% of children and to improve psychoemotional state in 55%. The correction of psychoemotional status of children changed their behavior towards diabetes, improved control and compensation of the disease.

  2. How does transcranial magnetic stimulation modify neuronal activity in the brain? Implications for studies of cognition

    DEFF Research Database (Denmark)

    Siebner, Hartwig R; Hartwigsen, Gesa; Kassuba, Tanja

    2009-01-01

    causes a synchronised high frequency burst of discharge in a relatively large population of neurones that is terminated by a long lasting GABAergic inhibition. The combination of artificial synchronisation of activity followed by depression effectively disrupts perceptual, motor and cognitive processes......Transcranial magnetic stimulation (TMS) uses a magnetic field to "carry" a short lasting electrical current pulse into the brain where it stimulates neurones, particularly in superficial regions of cerebral cortex. TMS can interfere with cognitive functions in two ways. A high intensity TMS pulse...... is at the time the stimulus is applied: if many neurones are close to firing threshold then the more of them are recruited by the pulse than at rest. Many studies have noted this context-dependent modulation. However, it is often assumed that the excitability of an area has a simple relationship to activity...

  3. Robust real-time robot-world calibration for robotized transcranial magnetic stimulation.

    Science.gov (United States)

    Richter, Lars; Ernst, Floris; Schlaefer, Alexander; Schweikard, Achim

    2011-12-01

    For robotized transcranial magnetic stimulation (TMS), the magnetic coil is placed on the patient's head by a robot. As the robotized TMS system requires tracking of head movements, robot and tracking camera need to be calibrated. However, for robotized TMS in a clinical setting, such calibration is required frequently. Mounting/unmounting a marker to the end effector and moving the robot into different poses is impractical. Moreover, if either system is moved during treatment, recalibration is required. To overcome this limitation, we propose to directly track a marker at link three of the articulated arm. Using forward kinematics and a constant marker transform to link three, the calibration can be performed instantly. Our experimental results indicate an accuracy similar to standard hand-eye calibration approaches. It also outperforms classical hand-held navigated TMS systems. This robust online calibration greatly enhances the system's user-friendliness and safety. Copyright © 2011 John Wiley & Sons, Ltd.

  4. The influence of low-frequency left prefrontal repetitive transcranial magnetic stimulation on memory for words but not for faces

    Czech Academy of Sciences Publication Activity Database

    Škrdlantová, L.; Horáček, J.; Dockery, C.; Lukavský, Jiří; Kopeček, M.; Preiss, M.; Novák, T.; Höschl, C.

    2005-01-01

    Roč. 54, č. 1 (2005), s. 123-128 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z70250504 Keywords : face memory * verbal memory * repetitive transcranial magnetic stimulation Subject RIV: AN - Psychology Impact factor: 1.806, year: 2005 http://www.biomed.cas.cz/physiolres/pdf/54/54_123.pdf

  5. Slow frequency repetitive transcranial magnetic stimulation affects reaction times, but not priming effects, in a masked prime task.

    NARCIS (Netherlands)

    Schlaghecken, F.; Munchau, A.; Bloem, B.R.; Rothwell, J.C.; Eimer, M.

    2003-01-01

    OBJECTIVE: Slow frequency repetitive transcranial magnetic stimulation (rTMS) reduces motor cortex excitability, but it is unclear whether this has behavioural consequences in healthy subjects. METHODS: We examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 80% of active motor

  6. Brain responses evoked by high-frequency repetitive transcranial magnetic stimulation: an event-related potential study

    NARCIS (Netherlands)

    Hamidi, M.; Slagter, H.A.; Tononi, G.; Postle, B.R.

    2010-01-01

    Background Many recent studies have used repetitive transcranial magnetic stimulation (rTMS) to study brain-behavior relationships. However, the pulse-to-pulse neural effects of rapid delivery of multiple TMS pulses are unknown largely because of TMS-evoked electrical artifacts limiting recording of

  7. Introducing transcranial magnetic stimulation (TMS) and its property of causal inference in investigating brain-function relationships

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Honk, E.J. van; Panksepp, J.

    2004-01-01

    Transcranial magnetic stimulation (TMS) is a method capable of transiently modulating neural excitability. Depending on the stimulation parameters information processing in the brain can be either enhanced or disrupted. This way the contribution of different brain areas involved in mental processes

  8. Cortical Inhibition in Attention Deficit Hyperactivity Disorder: New Insights from the Electroencephalographic Response to Transcranial Magnetic Stimulation

    Science.gov (United States)

    Bruckmann, Sarah; Hauk, Daniela; Roessner, Veit; Resch, Franz; Freitag, Christine M.; Kammer, Thomas; Ziemann, Ulf; Rothenberger, Aribert; Weisbrod, Matthias; Bender, Stephan

    2012-01-01

    Attention deficit hyperactivity disorder is one of the most frequent neuropsychiatric disorders in childhood. Transcranial magnetic stimulation studies based on muscle responses (motor-evoked potentials) suggested that reduced motor inhibition contributes to hyperactivity, a core symptom of the disease. Here we employed the N100 component of the…

  9. Transcranial magnetic stimulation reveals two functionally distinct stages of motor cortex involvement during perception of emotional body language

    NARCIS (Netherlands)

    Borgomaneri, Sara; Gazzola, Valeria; Avenanti, Alessio

    Studies indicate that perceiving emotional body language recruits fronto-parietal regions involved in action execution. However, the nature of such motor activation is unclear. Using transcranial magnetic stimulation (TMS) we provide correlational and causative evidence of two distinct stages of

  10. Transcranial magnetic stimulation reveals two functionally distinct stages of motor cortex involvement during perception of emotional body language

    NARCIS (Netherlands)

    Borgomaneri, S.; Gazzola, V.; Avenanti, A.

    2015-01-01

    Studies indicate that perceiving emotional body language recruits fronto-parietal regions involved in action execution. However, the nature of such motor activation is unclear. Using transcranial magnetic stimulation (TMS) we provide correlational and causative evidence of two distinct stages of

  11. Sleep disturbances in obsessive-compulsive disorder: Association with non-response to repetitive transcranial magnetic stimulation (rTMS)

    NARCIS (Netherlands)

    Donse, L.; Sack, A.T.; Fitzgerald, P.B.; Arns, M.W.

    2017-01-01

    Background Repetitive transcranial magnetic stimulation (rTMS) is a promising augmentation strategy for treatment-refractory OCD. However, a substantial group still fails to respond. Sleep disorders, e.g. circadian rhythm sleep disorders (CRSD), are highly prevalent in OCD and might mediate

  12. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Delvendahl, Igor; Pechmann, Astrid

    2012-01-01

    Transcranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor...

  13. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  14. Fifteen Minutes of Left Prefrontal Repetitive Transcranial Magnetic Stimulation Acutely Increases Thermal Pain Thresholds in Healthy Adults

    Directory of Open Access Journals (Sweden)

    Jeffrey J Borckardt

    2007-01-01

    Full Text Available BACKGROUND: Transcranial magnetic stimulation (TMS of the motor cortex appears to alter pain perception in healthy adults and in patients with chronic neuropathic pain. There is, however, emerging brain imaging evidence that the left prefrontal cortex is involved in pain inhibition in humans.

  15. Effects of bilateral repetitive transcranial magnetic stimulation on treatment resistant auditory-verbal hallucinations in schizophrenia : A randomized controlled trial

    NARCIS (Netherlands)

    Vercammen, Ans; Knegtering, Henderikus; Bruggeman, Richard; Westenbroek, Hanneke. M.; Jenner, Jack A.; Slooff, Cees J.; Wunderink, Lex; Aleman, Andre

    2009-01-01

    Background: Neuroimaging findings implicate bilateral superior temporal regions in the genesis of auditory-verbal hallucinations (AVH). This study aimed to investigate whether 1 Hz repetitive transcranial magnetic stimulation (rTMS) of the bilateral temporo-parietal region would lead to increased

  16. Field Distribution of Transcranial Static Magnetic Stimulation in Realistic Human Head Model.

    Science.gov (United States)

    Tharayil, Joseph J; Goetz, Stefan M; Bernabei, John M; Peterchev, Angel V

    2017-10-10

    The objective of this work was to characterize the magnetic field (B-field) that arises in a human brain model from the application of transcranial static magnetic field stimulation (tSMS). The spatial distribution of the B-field magnitude and gradient of a cylindrical, 5.08 cm × 2.54 cm NdFeB magnet were simulated in air and in a human head model using the finite element method and calibrated with measurements in air. The B-field was simulated for magnet placements over prefrontal, motor, sensory, and visual cortex targets. The impact of magnetic susceptibility of head tissues on the B-field was quantified. Peak B-field magnitude and gradient respectively ranged from 179-245 mT and from 13.3-19.0 T/m across the cortical targets. B-field magnitude, focality, and gradient decreased with magnet-cortex distance. The variation in B-field strength and gradient across the anatomical targets largely arose from the magnet-cortex distance. Head magnetic susceptibilities had negligible impact on the B-field characteristics. The half-maximum focality of the tSMS B-field ranged from 7-12 cm 3 . This is the first presentation and characterization of the three-dimensional (3D) spatial distribution of the B-field generated in a human brain model by tSMS. These data can provide quantitative dosing guidance for tSMS applications across various cortical targets and subjects. The finding that the B-field gradient is high near the magnet edges should be considered in studies where neural tissue is placed close to the magnet. The observation that susceptibility has negligible effects confirms assumptions in the literature. © 2017 International Neuromodulation Society.

  17. Is there potential for repetitive Transcranial Magnetic Stimulation (rTMS) as a treatment of OCD?

    Science.gov (United States)

    Zaman, Rashid; Robbins, Trevor W

    2017-09-01

    Obsessive-Compulsive Disorder (OCD) is a common and highly debilitating psychiatric disorder. Amongst OCD sufferers are a significant number (40-60%) of so-called non-responders who do not fully respond to commonly available treatments, which include medications (Selective Serotonin Reuptake Inhibitors-SSRIs) and cognitive behavior therapy (CBT). Modern 'neuromodulatory' techniques such as Deep Brain Stimulation (DBS), repetitive Transcranial Magnetic Stimulation (rTMS) and transcranial Direct Current Stimulation (tDCS) potentially offer alternative forms of treatment for OCD patients who either do not respond to, or are unable or unwilling to take SSRIs and undergo CBT. Although shown to be effective in treatment resistant OCD, DBS requires invasive neurosurgical procedures with associated risks. On the other hand, rTMS and tDCS are non-invasive forms of treatment, which are largely risk free, but the evidence of their efficacy so far is somewhat limited, with only small number of published studies. In this brief survey we will address the potential of rTMS as a therapeutic tool for OCD and review the published literature on the cortical targets for rTMS used so far. We will also discuss some of the newer variants of rTMS techniques only a few of which have been employed so far, and speculate whether there might be a place for rTMS as a standard treatment in OCD, along side CBT, SSRIs and DBS.

  18. The spectral features of EEG responses to transcranial magnetic stimulation of the primary motor cortex depend on the amplitude of the motor evoked potentials.

    Science.gov (United States)

    Fecchio, Matteo; Pigorini, Andrea; Comanducci, Angela; Sarasso, Simone; Casarotto, Silvia; Premoli, Isabella; Derchi, Chiara-Camilla; Mazza, Alice; Russo, Simone; Resta, Federico; Ferrarelli, Fabio; Mariotti, Maurizio; Ziemann, Ulf; Massimini, Marcello; Rosanova, Mario

    2017-01-01

    Transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) can excite both cortico-cortical and cortico-spinal axons resulting in TMS-evoked potentials (TEPs) and motor-evoked potentials (MEPs), respectively. Despite this remarkable difference with other cortical areas, the influence of motor output and its amplitude on TEPs is largely unknown. Here we studied TEPs resulting from M1 stimulation and assessed whether their waveform and spectral features depend on the MEP amplitude. To this aim, we performed two separate experiments. In experiment 1, single-pulse TMS was applied at the same supra-threshold intensity on primary motor, prefrontal, premotor and parietal cortices and the corresponding TEPs were compared by means of local mean field power and time-frequency spectral analysis. In experiment 2 we stimulated M1 at resting motor threshold in order to elicit MEPs characterized by a wide range of amplitudes. TEPs computed from high-MEP and low-MEP trials were then compared using the same methods applied in experiment 1. In line with previous studies, TMS of M1 produced larger TEPs compared to other cortical stimulations. Notably, we found that only TEPs produced by M1 stimulation were accompanied by a late event-related desynchronization (ERD-peaking at ~300 ms after TMS), whose magnitude was strongly dependent on the amplitude of MEPs. Overall, these results suggest that M1 produces peculiar responses to TMS possibly reflecting specific anatomo-functional properties, such as the re-entry of proprioceptive feedback associated with target muscle activation.

  19. Comparison of the induced fields using different coil configurations during deep transcranial magnetic stimulation.

    Directory of Open Access Journals (Sweden)

    Mai Lu

    Full Text Available Stimulation of deeper brain structures by transcranial magnetic stimulation (TMS plays a role in the study of reward and motivation mechanisms, which may be beneficial in the treatment of several neurological and psychiatric disorders. However, electric field distributions induced in the brain by deep transcranial magnetic stimulation (dTMS are still unknown. In this paper, the double cone coil, H-coil and Halo-circular assembly (HCA coil which have been proposed for dTMS have been numerically designed. The distributions of magnetic flux density, induced electric field in an anatomically based realistic head model by applying the dTMS coils were numerically calculated by the impedance method. Results were compared with that of standard figure-of-eight (Fo8 coil. Simulation results show that double cone, H- and HCA coils have significantly deep field penetration compared to the conventional Fo8 coil, at the expense of induced higher and wider spread electrical fields in superficial cortical regions. Double cone and HCA coils have better ability to stimulate deep brain subregions compared to that of the H-coil. In the mean time, both double cone and HCA coils increase risk for optical nerve excitation. Our results suggest although the dTMS coils offer new tool with potential for both research and clinical applications for psychiatric and neurological disorders associated with dysfunctions of deep brain regions, the selection of the most suitable coil settings for a specific clinical application should be based on a balanced evaluation between stimulation depth and focality.

  20. Simultaneous transcranial magnetic stimulation and single-neuron recording in alert non-human primates.

    Science.gov (United States)

    Mueller, Jerel K; Grigsby, Erinn M; Prevosto, Vincent; Petraglia, Frank W; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V; Sommer, Marc A; Egner, Tobias; Platt, Michael L; Grill, Warren M

    2014-08-01

    Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report new methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in awake monkeys (Macaca mulatta). We recorded action potentials within ∼1 ms after 0.4-ms TMS pulses and observed changes in activity that differed significantly for active stimulation as compared with sham stimulation. This methodology is compatible with standard equipment in primate laboratories, allowing easy implementation. Application of these tools will facilitate the refinement of next generation TMS devices, experiments and treatment protocols.

  1. Simultaneous transcranial magnetic stimulation and single neuron recording in alert non-human primates

    Science.gov (United States)

    Mueller, Jerel K.; Grigsby, Erinn M.; Prevosto, Vincent; Petraglia, Frank W.; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V.; Sommer, Marc A.; Egner, Tobias; Platt, Michael L.; Grill, Warren M.

    2014-01-01

    Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report novel methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in intact, awake monkeys (Macaca mulatta). We recorded action potentials within ~1 ms after 0.4 ms TMS pulses and observed changes in activity that differed significantly for active stimulation as compared to sham stimulation. The methodology is compatible with standard equipment in primate laboratories, allowing for easy implementation. Application of these new tools will facilitate the refinement of next generation TMS devices, experiments, and treatment protocols. PMID:24974797

  2. Subject-specific optimization of channel currents for multichannel transcranial magnetic stimulation.

    Science.gov (United States)

    Cline, Christopher C; Johnson, Nessa N; He, Bin

    2015-01-01

    The goal of this work is to develop a focal transcranial magnetic stimulation (TMS) system using a multichannel coil array for high-resolution neuromodulation. We proposed a novel spatially-distributed stimulation strategy to significantly improve the focality of TMS. Computer simulations were conducted to evaluate the proposed approach and test the merits of multichannel TMS. Three different multichannel coil arrays were modeled in addition to a conventional figure-8 coil for comparison. Simulations were performed on finite element head models of six subjects constructed from anatomical MR images via an automated pipeline. Multichannel TMS arrays exhibited significantly more focal induced electric field magnitudes compared to the figure-8 coil. Additionally, electrical steering of stimulation sites without physical movement of the coil array was demonstrated.

  3. Simulation of a conductive shield plate for the focalization of transcranial magnetic stimulation in the rat.

    Science.gov (United States)

    Gasca, Fernando; Richter, Lars; Schweikard, Achim

    2010-01-01

    Transcranial Magnetic Stimulation (TMS) in the rat is a powerful tool for investigating brain function. However, the state-of-the-art experiments are considerably limited because the stimulation usually affects undesired anatomical structures. A simulation of a conductive shield plate placed between the coil stimulator and the rat brain during TMS is presented. The Finite Element (FE) method is used to obtain the 3D electric field distribution on a four-layer rat head model. The simulations show that the shield plate with a circular window can improve the focalization of stimulation, as quantitatively seen by computing the three-dimensional half power region (HPR). Focalization with the shield plate showed a clear compromise with the attenuation of the induced field. The results suggest that the shield plate can work as a helpful tool for conducting TMS rat experiments on specific targets.

  4. An Ethics Perspective on Transcranial Magnetic Stimulation (TMS and Human Neuromodulation

    Directory of Open Access Journals (Sweden)

    Judy Illes

    2006-01-01

    Full Text Available This paper concerns the ethics of human neuromodulation using transcranial magnetic stimulation (TMS. We examine the challenges of modulating the brain with TMS through the research ethics lens and in clinical medicine for treating frank pathology, primarily in psychiatric diseases. We also consider contemporary issues raised in the neuroethics literature about managing unexpected findings, and relate these to TMS and to other frontier neurotechnology that is becoming openly available in the public domain. We argue that safety and informed consent are of paramount importance for TMS, but that personal values and sociocultural factors must also be considered when examining the promise of this technology and applications that ought to be highlighted for extra precautions.

  5. Repetitive transcranial magnetic stimulation to treat substance use disorders and compulsive behavior.

    Science.gov (United States)

    Protasio, Maria I B; da Silva, João P L; Arias-Carrión, Oscar; Nardi, Antonio E; Machado, Sergio; Cruz, Marcelo S

    2015-01-01

    Compulsions, like pathological gambling, binge-eating disorder, alcohol, tobacco or cocaine abuse and compulsive shopping have similar neurophysiological processing. This study aimed to examine the efficacy of repetitive transcranial magnetic stimulation (rTMS) in improving patient control over compulsive behavior. The rTMS modulatory role in cortical mesolimbic pathways possibly implies improvement of the inhibitory control system and compulsive consumption drive. Thus, craving reduction would be a component for control achievement. Within this context, 17 studies were found. Most studies applied rTMS over the left dorsolateral prefrontal cortex. Craving reduction was observed in 10 studies and was associated with improved control of compulsion in two of them. In one study reduction in consumption was found without reduction in craving. In addition, improvement in decision making was found in one study.

  6. Motor cortical representation in two different strength-training modalities revealed by transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Jørgensen, Rune Refsgaard; Osuna-Florentz, Patrick; Stevenson, Andrew James Thomas

    2017-01-01

    focused on minor distal muscles (4,5,6). Therefore, the aim of this study was to investigate which of two commonly used resistance-training regimes, explosive and non-explosive, yielded the largest cortical representations in vastus lateralis (VL) and biceps femoris (BF). Methods Eighteen participants...... were recruited and divided into two groups based on their training experience (explosive and non-explosive resistance trained). The participants had a minimum of two years of experience with either weightlifting (snatch and clean and jerk) or conventional resistance training. Transcranial magnetic......Introduction One of the sites that can be affected by motor training is the primary motor cortex (1,2,3), but sometimes learning a movement is only the beginning of a training regime. The effect of resistance training on corticospinal function is still unclear, and previous studies have often...

  7. A Review of Transcranial Magnetic Stimulation as a Treatment for Post-Traumatic Stress Disorder.

    Science.gov (United States)

    Clark, Caroline; Cole, Jeffrey; Winter, Christine; Williams, Kathy; Grammer, Geoffrey

    2015-10-01

    Patients with post-traumatic stress disorder (PTSD) may fail to achieve adequate relief despite treatment with psychotherapy, pharmacotherapy, or complementary medicine treatments. Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation procedure that can alter neuronal activity through administration of various pulse sequences and frequencies. TMS may theoretically have promise in correcting alterations observed in patients with PTSD. While the precise treatment location and pulse sequences remain undefined, current evidence suggests two promising targets, the right dorsolateral prefrontal cortex and the medial prefrontal cortex. The beneficial effects may be due to the secondary or indirect regulation of other brain structures that may be involved in the mood regulatory network. TMS may be an effective part of a comprehensive treatment program for PTSD, although significant work remains to define optimal treatment parameters and clarify how it fits within a broader traditional treatment program.

  8. The impact of transcranial magnetic stimulation on cognitive processing: an event-related potential study.

    Science.gov (United States)

    Evers, S; Böckermann, I; Nyhuis, P W

    2001-09-17

    Several neuropsychological studies have shown that repetitive transcranial magnetic stimulation (rTMS) can improve cognitive processing. We performed a study on the impact of rTMS on cognitive processing as measured by a neurophysiological method. In 14 healthy subjects, visually evoked event-related potentials (ERP) and mean choice reaction time were measured before and after 20 Hz rTMS of the left and of the right prefrontal cortex. The data were compared to sham stimulation and to 1 Hz single TMS. P3 latencies and reaction time were significantly decreased by rTMS of the left but not of the right prefrontal cortex, single TMS did not have any significant impact on the ERP components. We conclude that the facilitating effects of rTMS on cognitive processing can be proven even by objective neurophysiological measures.

  9. Is the human mirror neuron system plastic? Evidence from a transcranial magnetic stimulation study.

    Science.gov (United States)

    Mehta, Urvakhsh Meherwan; Waghmare, Avinash V; Thirthalli, Jagadisha; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

    2015-10-01

    Virtual lesions in the mirror neuron network using inhibitory low-frequency (1Hz) transcranial magnetic stimulation (TMS) have been employed to understand its spatio-functional properties. However, no studies have examined the influence of neuro-enhancement by using excitatory high-frequency (20Hz) repetitive transcranial magnetic stimulation (HF-rTMS) on these networks. We used three forms of TMS stimulation (HF-rTMS, single and paired pulse) to investigate whether the mirror neuron system facilitates the motor system during goal-directed action observation relative to inanimate motion (motor resonance), a marker of putative mirror neuron activity. 31 healthy individuals were randomized to receive single-sessions of true or sham HF-rTMS delivered to the left inferior frontal gyrus - a component of the human mirror system. Motor resonance was assessed before and after HF-rTMS using three TMS cortical reactivity paradigms: (a) 120% of resting motor threshold (RMT), (b) stimulus intensity set to evoke motor evoked potential of 1-millivolt amplitude (SI1mV) and (c) a short latency paired pulse paradigm. Two-way RMANOVA showed a significant group (true versus sham) X occasion (pre- and post-HF-rTMS motor resonance) interaction effect for SI1mV [F(df)=6.26 (1, 29), p=0.018] and 120% RMT stimuli [F(df)=7.01 (1, 29), p=0.013] indicating greater enhancement of motor resonance in the true HF-rTMS group than the sham-group. This suggests that HF-rTMS could adaptively modulate properties of the mirror neuron system. This neuro-enhancement effect is a preliminary step that can open translational avenues for novel brain stimulation therapeutics targeting social-cognition deficits in schizophrenia and autism. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Modulation of motor cortex excitability by paired peripheral and transcranial magnetic stimulation.

    Science.gov (United States)

    Kumru, Hatice; Albu, Sergiu; Rothwell, John; Leon, Daniel; Flores, Cecilia; Opisso, Eloy; Tormos, Josep Maria; Valls-Sole, Josep

    2017-10-01

    Repetitive application of peripheral electrical stimuli paired with transcranial magnetic stimulation (rTMS) of M1 cortex at low frequency, known as paired associative stimulation (PAS), is an effective method to induce motor cortex plasticity in humans. Here we investigated the effects of repetitive peripheral magnetic stimulation (rPMS) combined with low frequency rTMS ('magnetic-PAS') on intracortical and corticospinal excitability and whether those changes were widespread or circumscribed to the cortical area controlling the stimulated muscle. Eleven healthy subjects underwent three 10min stimulation sessions: 10HzrPMS alone, applied in trains of 5 stimuli every 10s (60 trains) on the extensor carpi radialis (ECR) muscle; rTMS alone at an intensity 120% of ECR threshold, applied over motor cortex of ECR and at a frequency of 0.1Hz (60 stimuli) and magnetic PAS, i.e., paired rPMS and rTMS. We recorded motor evoked potentials (MEPs) from ECR and first dorsal interosseous (FDI) muscles. We measured resting motor threshold, motor evoked potentials (MEP) amplitude at 120% of RMT, short intracortical inhibition (SICI) at interstimulus interval (ISI) of 2ms and intracortical facilitation (ICF) at an ISI of 15ms before and immediately after each intervention. Magnetic-PAS , but not rTMS or rPMS applied separately, increased MEP amplitude and reduced short intracortical inhibition in ECR but not in FDI muscle. Magnetic-PAS can increase corticospinal excitability and reduce intracortical inhibition. The effects may be specific for the area of cortical representation of the stimulated muscle. Application of magnetic-PAS might be relevant for motor rehabilitation. Copyright © 2017 International Federation of Clinical Neurophysiology. All rights reserved.

  11. Real-time visualization of magnetic flux densities for transcranial magnetic stimulation on commodity and fully immersive VR systems

    Science.gov (United States)

    Kalivarapu, Vijay K.; Serrate, Ciro; Hadimani, Ravi L.

    2017-05-01

    Transcranial Magnetic Stimulation (TMS) is a non-invasive procedure that uses time varying short pulses of magnetic fields to stimulate nerve cells in the brain. In this method, a magnetic field generator ("TMS coil") produces small electric fields in the region of the brain via electromagnetic induction. This technique can be used to excite or inhibit firing of neurons, which can then be used for treatment of various neurological disorders such as Parkinson's disease, stroke, migraine, and depression. It is however challenging to focus the induced electric field from TMS coils to smaller regions of the brain. Since electric and magnetic fields are governed by laws of electromagnetism, it is possible to numerically simulate and visualize these fields to accurately determine the site of maximum stimulation and also to develop TMS coils that can focus the fields on the targeted regions. However, current software to compute and visualize these fields are not real-time and can work for only one position/orientation of TMS coil, severely limiting their usage. This paper describes the development of an application that computes magnetic flux densities (h-fields) and visualizes their distribution for different TMS coil position/orientations in real-time using GPU shaders. The application is developed for desktop, commodity VR (HTC Vive), and fully immersive VR CAVETM systems, for use by researchers, scientists, and medical professionals to quickly and effectively view the distribution of h-fields from MRI brain scans.

  12. [The peculiarities of the application of transcranial magnetic therapy and electrical stimulation for the treatment of the patients presenting with various types of stroke].

    Science.gov (United States)

    Melnikova, E A

    2015-01-01

    In this article, the results of the authors' research, including analysis of the clinical and instrumental data concerning 203 patients with, stroke are presented. It is shown that the clinical effectiveness of the transcranial methods incorporated in the combined rehabilitation programs depends on the type of stroke and localization of the lesions. Specifically, the patients presenting with ischemic stroke of hemispheric localization experienced a neurophysiologically confirmed significant clinical improvement that became apparent after the consistent application of transcranial magnetic therapy and micropolarization. In the patients with ischemic stroke of stem localization, the positive influence on psychomotor recovery was achieved with the application of transcranial magnetic therapy, but transcranial micropolarization did not have an appreciable effect on the recovery of such patients. The patients presenting with hemorrhagic stroke did not experience any significant improvement of psychomotor parameters from transcranial magnetic therapy and transcranial micropolarization. The likely mechanism underlying the recovery of psychomotor processes under effect of transcranial magnetic therapy in the patients with ischemic stroke is the normalization of the frequency of interaction between brain structures. In addition, in the patients with ischemic stroke of hemispheric localization and in the patients with hemorrhagic stroke electrical myostimulation has a marked impact on the psychomotor recovery only in case of functional treatment. In the patients suffering from ischemic stroke of stem localization non-functional electromyostimulation significantly improves motor functions and cognitive motor control.

  13. A structurally detailed finite element human head model for simulation of transcranial magnetic stimulation.

    Science.gov (United States)

    Chen, Ming; Mogul, David Jeffery

    2009-04-30

    Computational studies of the head utilizing finite element models (FEMs) have been used to investigate a wide variety of brain-electromagnetic (EM) field interaction phenomena including magnetic stimulation of the head using transcranial magnetic stimulation (TMS), direct electric stimulation of the brain for electroconvulsive therapy, and electroencephalography source localization. However, no human head model of sufficient complexity for studying the biophysics under these circumstances has been developed which utilizes structures at both the regional and cellular levels and provides well-defined smooth boundaries between tissues of different conductivities and orientations. The main barrier for building such accurate head models is the complex modeling procedures that include 3D object reconstruction and optimized meshing. In this study, a structurally detailed finite element model of the human head was generated that includes details to the level of cerebral gyri and sulci by combining computed tomography and magnetic resonance images. Furthermore, cortical columns that contain conductive processes of pyramidal neurons traversing the neocortical layers were included in the head model thus providing structure at or near the cellular level. These refinements provide a much more realistic model to investigate the effects of TMS on brain electrophysiology in the neocortex.

  14. An investigation into the induced electric fields from transcranial magnetic stimulation

    Science.gov (United States)

    Hadimani, Ravi; Lee, Erik; Duffy, Walter; Waris, Mohammed; Siddiqui, Waquar; Islam, Faisal; Rajamani, Mahesh; Nathan, Ryan; Jiles, David; David C Jiles Team; Walter Duffy Collaboration

    Transcranial magnetic stimulation (TMS) is a promising tool for noninvasive brain stimulation that has been approved by the FDA for the treatment of major depressive disorder. To stimulate the brain, TMS uses large, transient pulses of magnetic field to induce an electric field in the head. This transient magnetic field is large enough to cause the depolarization of cortical neurons and initiate a synaptic signal transmission. For this study, 50 unique head models were created from MRI images. Previous simulation studies have primarily used a single head model, and thus give a limited image of the induced electric field from TMS. This study uses finite element analysis simulations on 50 unique, heterogeneous head models to better investigate the relationship between TMS and the electric field induced in brain tissues. Results showed a significant variation in the strength of the induced electric field in the brain, which can be reasonably predicted by the distance from the TMS coil to the stimulated brain. Further, it was seen that some models had high electric field intensities in over five times as much brain volume as other models.

  15. Effect of high-frequency repetitive transcranial magnetic stimulation on chronic central pain after mild traumatic brain injury: A pilot study

    Directory of Open Access Journals (Sweden)

    Gyu-sik Choi

    2018-01-01

    Full Text Available Objective: Central pain can occur following traumatic brain injury, leading to poor functional recovery, limitation of activities of daily living, and decreased quality of life. The aim of this study was to determine whether high-frequency (10 Hz repetitive transcranial magnetic stimulation, applied over the primary motor cortex of the affected hemisphere, can be used to manage chronic central pain after mild traumatic brain injury. Design: Prospective randomized feasibility study. Methods: Twelve patients with mild traumatic brain injury and chronic central pain were randomly assigned to transcranial magnetic stimulation (high-frequency stimulation, 10 sessions or sham groups. Diffuse tensor tractography revealed partially injured spinothalamocortical tracts in all recruited patients. A numerical rating scale (NRS was used to evaluate pain intensity during pre-treatment and immediately after the 5th transcranial magnetic stimulation session (post1, 10th transcranial magnetic stimulation session (post2, and 1 (post3, 2 (post4, and 4 weeks (post 5 after finishing treatment. Physical and mental health status were evaluated using the Short Form 36 Health Survey (SF-36, including physical and mental component scores (PCS, MCS. Results: The NRS score of the repetitive transcranial magnetic stimulation group was significantly lower than the sham group score at all clinical evaluation time-points during and after transcranial magnetic stimulation sessions. The transcranial magnetic stimulation group’s SF-36 PCS score was significantly higher at post2, post3, post4, and post5 compared with the sham group. Conclusion: High-frequency transcranial magnetic stimulation may be used to manage chronic central pain and improve quality of life in patients with mild traumatic brain injury. However, this is a pilot study and further research is needed.

  16. Effect of high-frequency repetitive transcranial magnetic stimulation on motor cortical excitability and sensory nerve conduction velocity in subacute-stage incomplete spinal cord injury patients.

    Science.gov (United States)

    Cha, Hyun Gyu; Ji, Sang-Goo; Kim, Myoung-Kwon

    2016-07-01

    [Purpose] The aim of the present study was to determine whether repetitive transcranial magnetic stimulation can improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients. [Subjects and Methods] This study was conducted on 20 subjects with diagnosed paraplegia due to spinal cord injury. These 20 subjects were allocated to an experimental group of 10 subjects that underwent active repetitive transcranial magnetic stimulation or to a control group of 10 subjects that underwent sham repetitive transcranial magnetic stimulation. The SCI patients in the experimental group underwent active repetitive transcranial magnetic stimulation and conventional rehabilitation therapy, whereas the spinal cord injury patients in the control group underwent sham repetitive transcranial magnetic stimulation and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for six-weeks. Latency, amplitude, and sensory nerve conduction velocity were assessed before and after the six week therapy period. [Results] A significant intergroup difference was observed for posttreatment velocity gains, but no significant intergroup difference was observed for amplitude or latency. [Conclusion] repetitive transcranial magnetic stimulation may be improve sensory recovery of the lower extremities in subacute-stage spinal cord injury patients.

  17. Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Andersen, Birgit; Westlund, Barbro; Krarup, Christian

    2003-01-01

    to estimate the proportion of motor units activated by a transcranial magnetic stimulus. Following a sustained contraction of the abductor digiti minimi muscle at 50 % maximal force maintained to exhaustion there was an immediate reduction of the TST response from > 95 % to about 60 %. This effect recovered...... conventional transcranial magnetic stimulation (TMS) and responses to peripheral nerve stimulation were recorded following the same fatigue protocol. The size of both the MEPs and the peripheral responses increased after the contraction and were in direct contrast to the decrease in size of the TST response....... This points to increased probability of repetitive spinal MN activation during fatigue even if some MNs in the pool failed to discharge. Silent period duration following cortical stimulation lengthened by an average of 55 ms after the contraction and recovered within a time course similar to that of the TST...

  18. Cognitive Impairment After Sleep Deprivation Rescued by Transcranial Magnetic Stimulation Application in Octodon degus.

    Science.gov (United States)

    Estrada, C; López, D; Conesa, A; Fernández-Gómez, F J; Gonzalez-Cuello, A; Toledo, F; Tunez, I; Blin, O; Bordet, R; Richardson, J C; Fernandez-Villalba, E; Herrero, M T

    2015-11-01

    Sleep is indispensable for maintaining regular daily life activities and is of fundamental physiological importance for cognitive performance. Sleep deprivation (SD) may affect learning capacity and the ability to form new memories, particularly with regard to hippocampus-dependent tasks. Transcranial magnetic stimulation (TMS) is a non-invasive procedure of electromagnetic induction that generates electric currents, activating nearby nerve cells in the stimulated cortical area. Several studies have looked into the potential therapeutic use of TMS. The present study was designed to evaluate how TMS could improve learning and memory functions following SD in Octodon degus. Thirty juvenile (18 months old) females were divided into three groups (control, acute, and chronic TMS treatment-with and without SD). TMS-treated groups were placed in plastic cylindrical cages designed to keep them immobile, while receiving head magnetic stimulation. SD was achieved by gently handling the animals to keep them awake during the night. Behavioral tests included radial arm maze (RAM), Barnes maze (BM), and novel object recognition. When TMS treatment was applied over several days, there was significant improvement of cognitive performance after SD, with no side effects. A single TMS session reduced the number of errors for the RAM test and improved latency and reduced errors for the BM test, which both evaluate spatial memory. Moreover, chronic TMS treatment brings about a significant improvement in both spatial and working memories.

  19. StimTrack: An open-source software for manual transcranial magnetic stimulation coil positioning.

    Science.gov (United States)

    Ambrosini, Emilia; Ferrante, Simona; van de Ruit, Mark; Biguzzi, Stefano; Colombo, Vera; Monticone, Marco; Ferriero, Giorgio; Pedrocchi, Alessandra; Ferrigno, Giancarlo; Grey, Michael J

    2018-01-01

    During Transcranial Magnetic Stimulation (TMS) experiments researchers often use a neuronavigation system to precisely and accurately maintain coil position and orientation. This study aimed to develop and validate an open-source software for TMS coil navigation. StimTrack uses an optical tracker and an intuitive user interface to facilitate the maintenance of position and orientation of any type of coil within and between sessions. Additionally, online access to navigation data is provided, hereby adding e.g. the ability to start or stop the magnetic stimulator depending on the distance to target or the variation of the orientation angles. StimTrack allows repeatable repositioning of the coil within 0.7mm for translation and 0.9) was obtained on all parameters computed on SR curves acquired using StimTrack. StimTrack showed a target accuracy similar to that of a commercial neuronavigation system (BrainSight, Rogue Research Inc.). Indeed, small differences both in position (∼0.2mm) and orientation (TMS. StimTrack allows researchers to tailor its functionality to their specific needs, providing added value that benefits experimental procedures and improves data quality. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Treatment for Traumatic Brain Injury in Mice Using Transcranial Magnetic Stimulation: A Preliminary Study

    Science.gov (United States)

    Carr, Alexandria; Zenitsky, Gary; Crowther, Lawrence; Hadimani, Ravi; Anantharam, Vellareddy; Kanthasamy, Anumantha; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive surgery-free tool used to stimulate the brain by time-varying magnetic fields. TMS is currently being investigated as a treatment for neurological disorders such as depression, Parkinson's disease and TBI. Before moving to human TMS/TBI trials, animal testing should be pursued to determine suitability and adverse effects. As an initial study, four healthy mice were treated with TMS at different power levels to determine short-term behavioral effects and set a control group baseline. The mouse's behavior was studied using the Rotorod test, which measures the animal's latency to fall off a rotating rod, and the Versamax test, which measures horizontal and vertical movement, and total distance traveled. The Rotorod test has shown for TMS power levels >=90% the mice begin to fall directly post-treatment. Similarly, the Versamax test has shown for power levels >=80% the mice are less mobile directly post-treatment. Versamax mobility was found to return to normal the day following treatment. These mice were housed in the facility for 4 months and the behavioral tests were repeated. Versamax results showed there was no significant variation in mobility indicating there are no long-term side effects of TMS treatment on the mice. This work was supported by the Barbara and James Palmer Endowment and the Carver Charitable Trust at the Department of Electrical and Computer Engineering, Iowa State University.

  1. Approximating transcranial magnetic stimulation with electric stimulation in mouse: a simulation study.

    Science.gov (United States)

    Barnes, Walter L; Lee, Won Hee; Peterchev, Angel V

    2014-01-01

    Rodent models are valuable for preclinical examination of novel therapeutic techniques, including transcranial magnetic stimulation (TMS). However, comparison of TMS effects in rodents and humans is confounded by inaccurate scaling of the spatial extent of the induced electric field in rodents. The electric field is substantially less focal in rodent models of TMS due to the technical restrictions of making very small coils that can handle the currents required for TMS. We examine the electric field distributions generated by various electrode configurations of electric stimulation in an inhomogeneous high-resolution finite element mouse model, and show that the electric field distributions produced by human TMS can be approximated by electric stimulation in mouse. Based on these results and the limits of magnetic stimulation in mice, we argue that the most practical and accurate way to model focal TMS in mice is electric stimulation through either cortical surface electrodes or electrodes implanted halfway through the mouse cranium. This approach could allow much more accurate approximation of the human TMS electric field focality and strength than that offered by TMS in mouse, enabling, for example, focal targeting of specific cortical regions, which is common in human TMS paradigms.

  2. The safety of transcranial magnetic stimulation with deep brain stimulation instruments.

    Science.gov (United States)

    Shimojima, Yoshio; Morita, Hiroshi; Nishikawa, Noriko; Kodaira, Minori; Hashimoto, Takao; Ikeda, Shu-Ichi

    2010-02-01

    Transcranial magnetic stimulation (TMS) has been employed in patients with an implanted deep brain stimulation (DBS) device. We investigated the safety of TMS using simulation models with an implanted DBS device. The DBS lead was inserted into plastic phantoms filled with dilute gelatin showing impedance similar to that of human brain. TMS was performed with three different types of magnetic coil. During TMS (1) electrode movement, (2) temperature change around the lead, and (3) TMS-induced current in various situations were observed. The amplitude and area of each evoked current were measured to calculate charge density of the evoked current. There was no movement or temperature increase during 0.2 Hz repetitive TMS with 100% stimulus intensity for 1 h. The size of evoked current linearly increased with TMS intensity. The maximum charge density exceeded the safety limit of 30 muC/cm(2)/phase during stimulation above the loops of the lead with intensity over 50% using a figure-eight coil. Strong TMS on the looped DBS leads should not be administered to avoid electrical tissue injury. Subcutaneous lead position should be paid enough attention for forthcoming situations during surgery. Copyright 2009 Elsevier Ltd. All rights reserved.

  3. Brain topological correlates of motor performance changes after repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Park, Chang-hyun; Chang, Won Hyuk; Yoo, Woo-Kyoung; Shin, Yong-Il; Kim, Sung Tae; Kim, Yun-Hee

    2014-05-01

    Repetitive transcranial magnetic stimulation (rTMS) influences the brain temporally beyond the stimulation period and spatially beyond the stimulation site. Application of rTMS over the primary motor cortex (M1) has been shown to lead to plastic changes in interregional connectivity over the motor system as well as alterations in motor performance. With a sequential combination of rTMS over the M1 and functional magnetic resonance imaging (fMRI), we sought changes in the topology of brain networks and specifically the association of brain topological changes with motor performance changes. In a sham-controlled parallel group experimental design, real or sham rTMS was administered to each of the 15 healthy subjects without prior motor-related dysfunctions, over the right M1 at a high frequency of 10 Hz. Before and after the intervention, fMRI data were acquired during a sequential finger motor task using the left, nondominant hand. Changes in the topology of brain networks were assessed in terms of global and local efficiency, which measures the efficiency in transporting information at global and local scales, respectively, provided by graph-theoretical analysis. Greater motor performance changes toward improvements after real rTMS were shown in individuals who exhibited more increases in global efficiency and more decreases in local efficiency. The enhancement of motor performance after rTMS is supposed to be associated with brain topological changes, such that global information exchange is facilitated, while local information exchange is restricted.

  4. A Retrospective Chart Review of 10 Hz Versus 20 Hz Repetitive Transcranial Magnetic Stimulation for Depression

    Directory of Open Access Journals (Sweden)

    Kristie L. DeBlasio

    2012-12-01

    Full Text Available We performed a retrospective chart review to examine the progress of patients with depression who received different frequencies of repetitive transcranial magnetic stimulation (rTMS delivered to the left dorsolateral prefrontal cortex (DLPFC. rTMS is a safe and effective alternative treatment for patients with various psychological and medical conditions. During treatment, a coil delivering a time-varying magnetic pulse placed over the scalp penetrates the skull, resulting in clinical improvement. There were 47 patients and three distinct treatment groups found: 10 Hz, 20 Hz, and a separate group who received both frequencies (10/20 Hz. The primary outcome indicator was the difference in Beck Depression Inventory–II (BDI-II scores. Secondary outcomes included categorical indicators of remission, response, and partial response rates as assessed with the BDI-II. In all 3 groups, the majority of patients had depression that remitted, with the highest rate occurring in the 20 Hz group. There were similar response rates in the 10 Hz and 20 Hz groups. There were no patients in the 10/20 Hz group whose depression responded and the highest partial response and nonresponse rates occurred in this group. Although within-group differences were significant from baseline to end of treatment, there were no between-group differences.

  5. Transcranial magnetic stimulation in developmental stuttering: Relations with previous neurophysiological research and future perspectives.

    Science.gov (United States)

    Busan, P; Battaglini, P P; Sommer, M

    2017-06-01

    Developmental stuttering (DS) is a disruption of the rhythm of speech, and affected people may be unable to execute fluent voluntary speech. There are still questions about the exact causes of DS. Evidence suggests there are differences in the structure and functioning of motor systems used for preparing, executing, and controlling motor acts, especially when they are speech related. Much research has been obtained using neuroimaging methods, ranging from functional magnetic resonance to diffusion tensor imaging and electroencephalography/magnetoencephalography. Studies using transcranial magnetic stimulation (TMS) in DS have been uncommon until recently. This is surprising considering the relationship between the functionality of the motor system and DS, and the wide use of TMS in motor-related disturbances such as Parkinson's Disease, Tourette's Syndrome, and dystonia. Consequently, TMS could shed further light on motor aspects of DS. The present work aims to investigate the use of TMS for understanding DS neural mechanisms by reviewing TMS papers in the DS field. Until now, TMS has contributed to the understanding of the excitatory/inhibitory ratio of DS motor functioning, also helping to better understand and critically review evidence about stuttering mechanisms obtained from different techniques, which allowed the investigation of cortico-basal-thalamo-cortical and white matter/connection dysfunctions. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  6. Navigated transcranial magnetic stimulation of the primary somatosensory cortex impairs perceptual processing of tactile temporal discrimination.

    Science.gov (United States)

    Hannula, Henri; Neuvonen, Tuomas; Savolainen, Petri; Tukiainen, Taru; Salonen, Oili; Carlson, Synnöve; Pertovaara, Antti

    2008-05-30

    Previous studies indicate that transcranial magnetic stimulation (TMS) with biphasic pulses applied approximately over the primary somatosensory cortex (S1) suppresses performance in vibrotactile temporal discrimination tasks; these previous results, however, do not allow separating perceptual influence from memory or decision-making. Moreover, earlier studies using external landmarks for directing biphasic TMS pulses to the cortex do not reveal whether the changes in vibrotactile task performance were due to action on S1 or an adjacent area. In the present study, we determined whether the S1 area representing a cutaneous test site is critical for perceptual processing of tactile temporal discrimination. Electrical test pulses were applied to the thenar skin of the hand and the subjects attempted to discriminate single from twin pulses. During discrimination task, monophasic TMS pulses or sham TMS pulses were directed anatomically accurately to the S1 area representing the thenar using magnetic resonance image-guided navigation. The subject's capacity to temporal discrimination was impaired with a decrease in the delay between the TMS pulse and the cutaneous test pulse from 50 to 0 ms. The result indicates that S1 area representing a cutaneous test site is involved in perceptual processing of tactile temporal discrimination.

  7. Contribution of transcranial magnetic stimulation to assessment of brain connectivity and networks.

    Science.gov (United States)

    Hallett, Mark; Di Iorio, Riccardo; Rossini, Paolo Maria; Park, Jung E; Chen, Robert; Celnik, Pablo; Strafella, Antonio P; Matsumoto, Hideyuki; Ugawa, Yoshikazu

    2017-11-01

    The goal of this review is to show how transcranial magnetic stimulation (TMS) techniques can make a contribution to the study of brain networks. Brain networks are fundamental in understanding how the brain operates. Effects on remote areas can be directly observed or identified after a period of stimulation, and each section of this review will discuss one method. EEG analyzed following TMS is called TMS-evoked potentials (TEPs). A conditioning TMS can influence the effect of a test TMS given over the motor cortex. A disynaptic connection can be tested also by assessing the effect of a pre-conditioning stimulus on the conditioning-test pair. Basal ganglia-cortical relationships can be assessed using electrodes placed in the process of deep brain stimulation therapy. Cerebellar-cortical relationships can be determined using TMS over the cerebellum. Remote effects of TMS on the brain can be found as well using neuroimaging, including both positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). The methods complement each other since they give different views of brain networks, and it is often valuable to use more than one technique to achieve converging evidence. The final product of this type of work is to show how information is processed and transmitted in the brain. Published by Elsevier B.V.

  8. Measuring and manipulating brain connectivity with resting state functional connectivity magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS)

    OpenAIRE

    Fox, Michael D.; Halko, Mark A.; Eldaief, Mark C.; Pascual-Leone, Alvaro

    2012-01-01

    Both resting state functional magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS) are increasingly popular techniques that can be used to non-invasively measure brain connectivity in human subjects. TMS shows additional promise as a method to manipulate brain connectivity. In this review we discuss how these two complimentary tools can be combined to optimally study brain connectivity and manipulate distributed brain networks. Important clinical applications include...

  9. Using imaging to target the prefrontal cortex for transcranial magnetic stimulation studies in treatment-resistant depression

    OpenAIRE

    Johnson, Kevin A.; Ramsey, Dave; Kozel, Frank A.; Bohning, Daryl E.; Anderson, Berry; Nahas, Ziad; Sacke?m, Harold A.; George, Mark S.

    2006-01-01

    Structural imaging studies of the brains of patients with treatment-resistant depression (TRD) have found several abnormalities, including smaller hippocampus, orbitofrontal cortex, or pre?frontal cortex. Transcranial magnetic stimulation (TMS) is a noninvasive means of modulating brain activity, and has shown antidepressant treatment efficacy. 1 The initial methods used for targeting the prefrontal cortex are most likely insufficient. Herwig et al found that a common rule-based approach (the...

  10. Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study

    OpenAIRE

    Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R.

    2016-01-01

    Background A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-depen...

  11. A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

    OpenAIRE

    Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.

    2013-01-01

    Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimu...

  12. A 2-in-1 single-element coil design for transcranial magnetic stimulation and magnetic resonance imaging.

    Science.gov (United States)

    Lu, Hai; Wang, Shumin

    2018-01-01

    To demonstrate the feasibility of turning transcranial magnetic stimulation (TMS) coil for MRI signal reception. A critically coupled network was formed by using a resonated turn of TMS coil as the secondary and a regular radiofrequency (RF) coil as the primary. A third coil was positioned between the two coils for detuning during RF transmission. Bench measurement, numerical simulation, and MRI experiment were performed for validation. The signal-to-noise ratio of the proposed 2-in-1 coil is 35% higher in its field of view, compared with a MRI-only reference coil of the same size, made by the same material, and backed up by an untuned TMS coil, but lower than a RF surface coil of the same size without any TMS coil nearby. Spin-echo images of the human brain further validated its performance. The proposed method can transform TMS coil for MRI signal acquisition with virtually no modifications on the TMS side. It not only enables flexible and close positioning of TMS coil inside MRI scanner, but also improves the signal-to-noise ratio compared with conventional implementations. It can be applied as a building block for developing advanced concurrent TMS/MRI hardware. Magn Reson Med 79:582-587, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  13. [Computer modelling of electroconvulsive treatment and transcranial magnetic stimulation--an explanation of poor efficacy of the magnetic method].

    Science.gov (United States)

    Zyss, Tomasz; Krawczyk, Andrzej; Zieba, Andrzej; Dudek, Dominika; Hese, Robert T; Drzymała, Paweł; Wiak, Sławomir; Sawicki, Bartosz; Starzyński, Jacek; Szmurło, Robert; Wincenciak, Stanisław

    2010-01-01

    With help of informatics technology it is possible to simulate various physiological processes in virtual models of biological structures. In a created realistic model of the human head we made some comparative investigations over physical phenomena accompanying the electroconvulsive treatment ECT and transcranial magnetic stimulation TMS--two methods with confirmed (ECT) or presumable (TMS) antidepressant efficacy. The present investigations are a continuation of the earlier conducted study in the simple spherical model of the head. Investigations confirmed, that magnetic stimulation TMS generates a considerably weaker current flow in the brain than it is present in electroconvulsive technique. Applying of such weak stimulation in modus,,at haphazard", i.e. on the brain area which does not need to be metabolically disturbed in this patient--cannot cause an antidepressant effect at all. The results of the investigations explain not only the safety of the magnetic method, but the weak effectiveness of this method. The authors propose some methods for improvement of TMS efficacy.

  14. Effects of repetitive transcranial magnetic stimulation on lower extremity spasticity and motor function in stroke patients.

    Science.gov (United States)

    Rastgoo, Maryam; Naghdi, Sofia; Nakhostin Ansari, Noureddin; Olyaei, Gholamreza; Jalaei, Shohreh; Forogh, Bijan; Najari, Hamidreza

    2016-09-01

    To investigate the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) on lower extremity (LE) spasticity, motor function and motor neurone excitability in chronic stroke patients. This study was a randomised sham-controlled cross-over trial with 1-week follow-up. A total of 20 post-stroke patients were randomised to receive active (n = 10) or sham (n = 10) rTMS. Fourteen of them (7 in each group) crossed over to the sham or active rTMS after a washout period of 1 month. Interventions consist of five consecutive daily sessions of active or sham rTMS to the unaffected lower extremity motor area (1000 pulses; 1 Hz; 90% of the tibialis anterior motor threshold). Outcome measures were modified modified ashworth scale (MMAS), the H-reflex, lower extremity section of Fugl-Mayer assessment (LE-FMA) and timed UP and GO (TUG) test. All outcomes were measured at three levels in each intervention period: pre- and post-intervention and 1-week follow-up. Friedman's test revealed significant improvement in MMAS score only after active rTMS. This improvement lasted for one week after the active rTMS. Repeated measure analysis of variance (ANOVA) showed significant time*intervention interaction for LE-FMA. There are no differences between groups for the MMAS and LE-FMA. No significant change in Hmax/Mmax ratio and TUG test was noted. Low-frequency rTMS over the LE motor area can improve clinical measures of muscle spasticity and motor function. More studies are needed to clarify the changes underlying this improvement in spasticity. Implications for Rehabilitation Spasticity is a common disorder and one of the causes of long-term disability after stroke. Physical therapy modalities, oral medications, focal intervention and surgical procedures have been used for spasticity reduction. Beneficial effect of the repetitive transcranial magnetic stimulation (rTMS) for post-stroke upper extremity spasticity reduction and motor function improvement was

  15. A systematic review for the antidepressant effects of sleep deprivation with repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Tang, Qing; Li, Guangming; Wang, Anguo; Liu, Tao; Feng, Shenggang; Guo, Zhiwei; Chen, Huaping; He, Bin; McClure, Morgan A; Ou, Jun; Xing, Guoqiang; Mu, Qiwen

    2015-11-14

    Sleep deprivation (SD) and repetitive transcranial magnetic stimulation (rTMS) have been commonly used to treat depression. Recent studies suggest that co-therapy with rTMS and SD may produce better therapeutic effects than either therapy alone. Therefore, this study was to review the current findings to determine if rTMS can augment the therapeutic effects of SD on depression. Embase, JSTOR, Medline, PubMed, ScienceDirect, and the Cochrane Central Register of Controlled Trials were searched for clinical studies published between January 1985 and March 2015 using the search term "rTMS/repetitive transcranial magnetic stimulation AND sleep deprivation AND depress*". Only randomized and sham-controlled trials (RCTs) involving the combined use of rTMS and SD in depression patients were included in this systematic review. The scores of the Hamilton Rating Scale for Depression were extracted as primary outcome measures. Three RCTs with 72 patients that met the inclusion criteria were included for the systematic review. One of the trials reported skewed data and was described alone. The other two studies, which involved 30 patients in the experimental group (SD + active rTMS) and 22 patients in the control group (SD + sham rTMS), reported normally distributed data. The primary outcome measures showed different results among the three publications: two of which showed great difference between the experimental and the control subjects, and the other one showed non-significant antidepressant effect of rTMS on SD. In addition, two of the included studies reported secondary outcome measures with Clinical Global Impression Rating Scale and a self-reported well-being scale which presented good improvement for the depressive patients in the experiment group when compared with the control. The follow-up assessments in two studies indicated maintained results with the immediate measurements. From this study, an overview of the publications concerning the combined use of rTMS and

  16. Transcranial Magnetic Stimulation over Left Inferior Frontal and Posterior Temporal Cortex Disrupts Gesture-Speech Integration.

    Science.gov (United States)

    Zhao, Wanying; Riggs, Kevin; Schindler, Igor; Holle, Henning

    2018-02-21

    Language and action naturally occur together in the form of cospeech gestures, and there is now convincing evidence that listeners display a strong tendency to integrate semantic information from both domains during comprehension. A contentious question, however, has been which brain areas are causally involved in this integration process. In previous neuroimaging studies, left inferior frontal gyrus (IFG) and posterior middle temporal gyrus (pMTG) have emerged as candidate areas; however, it is currently not clear whether these areas are causally or merely epiphenomenally involved in gesture-speech integration. In the present series of experiments, we directly tested for a potential critical role of IFG and pMTG by observing the effect of disrupting activity in these areas using transcranial magnetic stimulation in a mixed gender sample of healthy human volunteers. The outcome measure was performance on a Stroop-like gesture task (Kelly et al., 2010a), which provides a behavioral index of gesture-speech integration. Our results provide clear evidence that disrupting activity in IFG and pMTG selectively impairs gesture-speech integration, suggesting that both areas are causally involved in the process. These findings are consistent with the idea that these areas play a joint role in gesture-speech integration, with IFG regulating strategic semantic access via top-down signals acting upon temporal storage areas. SIGNIFICANCE STATEMENT Previous neuroimaging studies suggest an involvement of inferior frontal gyrus and posterior middle temporal gyrus in gesture-speech integration, but findings have been mixed and due to methodological constraints did not allow inferences of causality. By adopting a virtual lesion approach involving transcranial magnetic stimulation, the present study provides clear evidence that both areas are causally involved in combining semantic information arising from gesture and speech. These findings support the view that, rather than being

  17. Sensor probes and phantoms for advanced transcranial magnetic stimulation system developments

    Science.gov (United States)

    Meng, Qinglei; Patel, Prashil; Trivedi, Sudhir; Du, Xiaoming; Hong, Elliot; Choa, Fow-Sen

    2015-05-01

    Transcranial magnetic stimulation (TMS) has become one of the most widely used noninvasive method for brain tissue stimulation and has been used as a treatment tool for various neurological and psychiatric disorders including migraine, stroke, Parkinson's disease, dystonia, tinnitus and depression. In the process of developing advanced TMS deep brain stimulation tools, we need first to develop field measurement devices like sensory probes and brain phantoms, which can be used to calibrate the TMS systems. Currently there are commercially available DC magnetic or electric filed measurement sensors, but there is no instrument to measure transient fields. In our study, we used a commercial figure-8 shaped TMS coil to generate transient magnetic field and followed induced field and current. The coil was driven by power amplified signal from a pulse generator with tunable pulse rate, amplitude, and duration. In order to obtain a 3D plot of induced vector electric field, many types of probes were designed to detect single component of electric-field vectors along x, y and z axis in the space around TMS coil. We found that resistor probes has an optimized signal-to-noise ratio (SNR) near 3k ohm but it signal output is too weak compared with other techniques. We also found that inductor probes can have very high output for Curl E measurement, but it is not the E-field distribution we are interested in. Probes with electrical wire wrapped around iron coil can directly measure induced E-field with high sensitivity, which matched computer simulation results.

  18. A review of transcranial magnetic stimulation and multimodal neuroimaging to characterize post-stroke neuroplasticity

    Directory of Open Access Journals (Sweden)

    Angela Michelle Auriat

    2015-10-01

    Full Text Available Following stroke, the brain undergoes various stages of recovery where the central nervous system can reorganize neural circuitry (neuroplasticity both spontaneously and with the aid of behavioural rehabilitation and non-invasive brain stimulation. Multiple neuroimaging techniques can characterize common structural and functional stroke-related deficits, and importantly, help predict recovery of function. Diffusion tensor imaging (DTI typically reveals increased overall diffusivity throughout the brain following stroke, and is capable of indexing the extent of white matter damage. Magnetic resonance spectroscopy (MRS provides an index of metabolic changes in surviving neural tissue after stroke, serving as a marker of brain function. The neural correlates of altered brain activity after stroke have been demonstrated by abnormal activation of sensorimotor cortices during task performance, and at rest, using functional magnetic resonance imaging (fMRI. Electroencephalography (EEG has been used to characterize motor dysfunction in terms of increased cortical amplitude in the sensorimotor regions when performing upper-limb movement, indicating abnormally increased cognitive effort and planning in individuals with stroke. Transcranial magnetic stimulation (TMS work reveals changes in ipsilesional and contralesional cortical excitability in the sensorimotor cortices. The severity of motor deficits indexed using TMS has been linked to the magnitude of activity imbalance between the sensorimotor cortices. In this paper we will provide a narrative review of data from studies utilizing DTI, MRS, fMRI, EEG and brain stimulation techniques focusing on TMS and its combination with uni and multi-modal neuroimaging methods to assess recovery after stroke. Approaches that delineate the best measures with which to predict or positively alter outcomes will be highlighted.

  19. Effects of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper limb motor dysfunction in patients with subacute cerebral infarction.

    Science.gov (United States)

    Li, Jiang; Meng, Xiang-Min; Li, Ru-Yi; Zhang, Ru; Zhang, Zheng; Du, Yi-Feng

    2016-10-01

    Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the excitability of cortical neurons. However, there are few studies concerning the use of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper-limb motor function after cerebral infarction. We hypothesized that different frequencies of repetitive transcranial magnetic stimulation in patients with cerebral infarction would produce different effects on the recovery of upper-limb motor function. This study enrolled 127 patients with upper-limb dysfunction during the subacute phase of cerebral infarction. These patients were randomly assigned to three groups. The low-frequency group comprised 42 patients who were treated with 1 Hz repetitive transcranial magnetic stimulation on the contralateral hemisphere primary motor cortex (M1). The high-frequency group comprised 43 patients who were treated with 10 Hz repetitive transcranial magnetic stimulation on ipsilateral M1. Finally, the sham group comprised 42 patients who were treated with 10 Hz of false stimulation on ipsilateral M1. A total of 135 seconds of stimulation was applied in the sham group and high-frequency group. At 2 weeks after treatment, cortical latency of motor-evoked potentials and central motor conduction time were significantly lower compared with before treatment. Moreover, motor function scores were significantly improved. The above indices for the low- and high-frequency groups were significantly different compared with the sham group. However, there was no significant difference between the low- and high-frequency groups. The results show that low- and high-frequency repetitive transcranial magnetic stimulation can similarly improve upper-limb motor function in patients with cerebral infarction.

  20. A Computational Model for Real-Time Calculation of Electric Field due to Transcranial Magnetic Stimulation in Clinics

    Directory of Open Access Journals (Sweden)

    Alessandra Paffi

    2015-01-01

    Full Text Available The aim of this paper is to propose an approach for an accurate and fast (real-time computation of the electric field induced inside the whole brain volume during a transcranial magnetic stimulation (TMS procedure. The numerical solution implements the admittance method for a discretized realistic brain model derived from Magnetic Resonance Imaging (MRI. Results are in a good agreement with those obtained using commercial codes and require much less computational time. An integration of the developed code with neuronavigation tools will permit real-time evaluation of the stimulated brain regions during the TMS delivery, thus improving the efficacy of clinical applications.

  1. The Effectiveness of Repetitive Transcranial Magnetic Stimulation for Poststroke Apathy Is Associated with Improved Interhemispheric Functional Connectivity.

    Science.gov (United States)

    Mitaki, Shingo; Onoda, Keiichi; Abe, Satoshi; Oguro, Hiroaki; Yamaguchi, Shuhei

    2016-12-01

    Poststroke apathy is relatively common and has negative effects on the functional recovery of the patient; however, few reports have demonstrated the existence of effective treatments for poststroke apathy. Here, we describe a case of poststroke apathy that was successfully treated with repetitive transcranial magnetic stimulation (rTMS). Using resting-state functional magnetic resonance imaging, we detected improved interhemispheric functional connectivity that was correlated with the patient's recovery from poststroke apathy. Our case suggests that rTMS can improve the transfer of information through the corpus callosum, which is crucial for helping patients recover from poststroke apathy. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Repetitieve transcraniële magnetische stimulatie bij depressie; stimulatie van het brein om de psyche te genezen = [Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche

    NARCIS (Netherlands)

    Helmich, R.C.G.; Snijders, A.H.; Verkes, R.J.; Bloem, B.R.

    2004-01-01

    Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The

  3. Reduced motor cortical inhibition in migraine: A blinded transcranial magnetic stimulation study.

    Science.gov (United States)

    Neverdahl, J P; Omland, P M; Uglem, M; Engstrøm, M; Sand, T

    2017-12-01

    To investigate motor cortical excitability, inhibition, and facilitation with navigated transcranial magnetic stimulation (TMS) in migraine in a blinded cross-sectional study. Resting motor threshold (RMT), cortical silent period (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were compared in 27 interictal migraineurs and 33 controls. 24 female interictal migraineurs and 27 female controls were compared in subgroup analyses. Seven preictal migraineurs were also compared to the interictal group in a hypothesis-generating analysis. Investigators were blinded for diagnosis during recording and analysis of data. SICI was decreased in interictal migraineurs when compared to healthy controls (p=0.013), CSP was shortened in female interictal migraineurs (p=0.041). ICF was decreased in preictal compared to interictal migraineurs (p=0.023). RMT and ICF were not different between interictal migraineurs and controls. Cortical inhibition was decreased in migraineurs between attacks, primarily in a female subgroup, indicating an importance of altered cortical inhibition in migraine. Previous studies on motor cortical excitability in migraineurs have yielded varying results. This relatively large and blinded study provides support for altered cortical inhibition in migraine. Measuring intracortical facilitation in the period preceding migraine attacks may be of interest for future studies. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  4. The precise adjustment of coil location for transcranial magnetic stimulation during dynamic motion.

    Science.gov (United States)

    Kitamura, Taku; Yaeshima, Katsutoshi; Yamamoto, Shin-Ichiro; Kawashima, Noritaka

    2013-01-01

    Transcranial magnetic stimulation (TMS) to the cerebral cortex is a major in vitro technique that is used in the field of neurophysiology. The magnitude of the motor-evoked potentials (MEP) that are elicited by TMS to the primary motor cortex reflect the excitability of the corticospinal pathway. MEPs are very sensitive to the scalp location of the stimulus coil, especially when corticospinal excitability is recorded during walking or other dynamic motions. In this study, we created a coil navigational system that consisted of three-dimensional motion analysis cameras, rigid bodies on the head and coil, and programming software. In order to evaluate the feasibility of the use of our system, pseudo TMS was applied during treadmill walking with or without the navigational system. As a result, we found that the variances due to coil location and/or distance from the target site were reduced with our system. This technique enabled us to realize high precision and accuracy in coil placement, even during dynamic motion.

  5. Estimation of cortical silent period following transcranial magnetic stimulation using a computerised cumulative sum method.

    Science.gov (United States)

    King, Nicolas K K; Kuppuswamy, Annapoorna; Strutton, Paul H; Davey, Nick J

    2006-01-15

    The cortical silent period (CSP) following transcranial magnetic stimulation (TMS) of the motor cortex can be used to measure intra-cortical inhibition and changes in a number of important pathologies affecting the central nervous system. The main drawback of this technique has been the difficulty in accurately identifying the onset and offset of the cortical silent period leading to inter-observer variability. We developed an automated method based on the cumulative sum (Cusum) technique to improve the determination of the duration and area of the cortical silent period. This was compared with experienced raters and two other automated methods. We showed that the automated Cusum method reliably correlated with the experienced raters for both duration and area of CSP. Compared with the automated methods, the Cusum also showed the strongest correlation with the experienced raters. Our results show the Cusum method to be a simple, graphical and powerful method of detecting low-intensity CSP that can be easily automated using standard software.

  6. Transcranial magnetic stimulation and connectivity mapping: tools for studying the neural bases of brain disorders.

    Science.gov (United States)

    Hampson, M; Hoffman, R E

    2010-01-01

    There has been an increasing emphasis on characterizing pathophysiology underlying psychiatric and neurological disorders in terms of altered neural connectivity and network dynamics. Transcranial magnetic stimulation (TMS) provides a unique opportunity for investigating connectivity in the human brain. TMS allows researchers and clinicians to directly stimulate cortical regions accessible to electromagnetic coils positioned on the scalp. The induced activation can then propagate through long-range connections to other brain areas. Thus, by identifying distal regions activated during TMS, researchers can infer connectivity patterns in the healthy human brain and can examine how those patterns may be disrupted in patients with different brain disorders. Conversely, connectivity maps derived using neuroimaging methods can identify components of a dysfunctional network. Nodes in this dysfunctional network accessible as targets for TMS by virtue of their proximity to the scalp may then permit TMS-induced alterations of components of the network not directly accessible to TMS via propagated effects. Thus TMS can provide a portal for accessing and altering neural dynamics in networks that are widely distributed anatomically. Finally, when long-term modulation of network dynamics is induced by trains of repetitive TMS, changes in functional connectivity patterns can be studied in parallel with changes in patient symptoms. These correlational data can elucidate neural mechanisms underlying illness and recovery. In this review, we focus on the application of these approaches to the study of psychiatric and neurological illnesses.

  7. Combining transcranial magnetic stimulation and functional imaging in cognitive brain research: possibilities and limitations.

    Science.gov (United States)

    Sack, Alexander T; Linden, David E J

    2003-09-01

    Transcranial magnetic stimulation (TMS) is a widely used tool for the non-invasive study of basic neurophysiological processes and the relationship between brain and behavior. We review the physical and physiological background of TMS and discuss the large body of perceptual and cognitive studies, mainly in the visual domain, that have been performed with TMS in the past 15 years. We compare TMS with other neurophysiological and neuropsychological research tools and propose that TMS, compared with the classical neuropsychological lesion studies, can make its own unique contribution. As the main focus of this review, we describe the different approaches of combining TMS with functional neuroimaging techniques. We also discuss important shortcomings of TMS, especially the limited knowledge concerning its physiological effects, which often make the interpretation of TMS results ambiguous. We conclude with a critical analysis of the resulting conceptual and methodological limitations that the investigation of functional brain-behavior relationships still has to face. We argue that while some of the methodological limitations of TMS applied alone can be overcome by combination with functional neuroimaging, others will persist until its physical and physiological effects can be controlled.

  8. Transcranial magnetic stimulation and connectivity mapping: tools for studying the neural bases of brain disorders.

    Directory of Open Access Journals (Sweden)

    Michelle Hampson

    2010-08-01

    Full Text Available There has been an increasing emphasis on characterizing pathophysiology underlying psychiatric and neurological disorders in terms of altered neural connectivity and network dynamics. Transcranial magnetic stimulation (TMS provides a unique opportunity for investigating connectivity in the human brain. TMS allows researchers and clinicians to directly stimulate cortical regions accessible to electromagnetic coils positioned on the scalp. The induced activation can then propagate through long-range connections to other brain areas. Thus, by identifying distal regions activated during TMS, researchers can infer connectivity patterns in the healthy human brain and can examine how those patterns may be disrupted in patients with different brain disorders. Conversely, connectivity maps derived using neuroimaging methods can identify components of a dysfunctional network. Nodes in this dysfunctional network accessible as targets for TMS by virtue of their proximity to the scalp may then permit TMS-induced alterations of components of the network not directly accessible to TMS via propagated effects. Thus TMS can provide a portal for accessing and altering neural dynamics in networks that are widely distributed anatomically. Finally, when long-term modulation of network dynamics is induced by trains of repetitive TMS, changes in functional connectivity patterns can be studied in parallel with changes in patient symptoms. These correlational data can elucidate neural mechanisms underlying illness and recovery. In this review, we focus on the application of these approaches to the study of psychiatric and neurological illnesses.

  9. Whole field tendencies in transcranial magnetic stimulation: A systematic review with data and text mining.

    Science.gov (United States)

    Dias, Alvaro Machado; Mansur, Carlos Gustavo; Myczkowski, Martin; Marcolin, Marco

    2011-06-01

    Transcranial magnetic stimulation (TMS) has played an important role in the fields of psychiatry, neurology and neuroscience, since its emergence in the mid-1980s; and several high quality reviews have been produced since then. Most high quality reviews serve as powerful tools in the evaluation of predefined tendencies, but they cannot actually uncover new trends within the literature. However, special statistical procedures to 'mine' the literature have been developed which aid in achieving such a goal. This paper aims to uncover patterns within the literature on TMS as a whole, as well as specific trends in the recent literature on TMS for the treatment of depression. Data mining and text mining. Currently there are 7299 publications, which can be clustered in four essential themes. Considering the frequency of the core psychiatric concepts within the indexed literature, the main results are: depression is present in 13.5% of the publications; Parkinson's disease in 2.94%; schizophrenia in 2.76%; bipolar disorder in 0.158%; and anxiety disorder in 0.142% of all the publications indexed in PubMed. Several other perspectives are discussed in the article. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Contribution of transcranial magnetic stimulation to the understanding of cortical mechanisms involved in motor control.

    Science.gov (United States)

    Reis, Janine; Swayne, Orlando B; Vandermeeren, Yves; Camus, Mickael; Dimyan, Michael A; Harris-Love, Michelle; Perez, Monica A; Ragert, Patrick; Rothwell, John C; Cohen, Leonardo G

    2008-01-15

    Transcranial magnetic stimulation (TMS) was initially used to evaluate the integrity of the corticospinal tract in humans non-invasively. Since these early studies, the development of paired-pulse and repetitive TMS protocols allowed investigators to explore inhibitory and excitatory interactions of various motor and non-motor cortical regions within and across cerebral hemispheres. These applications have provided insight into the intracortical physiological processes underlying the functional role of different brain regions in various cognitive processes, motor control in health and disease and neuroplastic changes during recovery of function after brain lesions. Used in combination with neuroimaging tools, TMS provides valuable information on functional connectivity between different brain regions, and on the relationship between physiological processes and the anatomical configuration of specific brain areas and connected pathways. More recently, there has been increasing interest in the extent to which these physiological processes are modulated depending on the behavioural setting. The purpose of this paper is (a) to present an up-to-date review of the available electrophysiological data and the impact on our understanding of human motor behaviour and (b) to discuss some of the gaps in our present knowledge as well as future directions of research in a format accessible to new students and/or investigators. Finally, areas of uncertainty and limitations in the interpretation of TMS studies are discussed in some detail.

  11. Transcranial magnetic stimulation (TMS): compared sensitivity of different motor response parameters in ALS.

    Science.gov (United States)

    Pouget, J; Trefouret, S; Attarian, S

    2000-06-01

    Owing to the low sensitivity of clinical signs in assessing upper motor neuron (UMN) involvement in ALS, there is a need for investigative tools capable of detecting abnormal function of the pyramidal tract. Transcranial magnetic stimulation (TMS) may contribute to the diagnosis by reflecting a UMN dysfunction that is not clinically detectable. Several parameters for the motor responses to TMS can be evaluated with different levels of significance in healthy subjects compared with ALS patients. The central motor conduction time, however, is not sensitive in detecting subclinical UMN defects in individual ALS patients. The amplitude of the motor evoked potential (MEP), expressed as the percentage of the maximum wave, also has a low sensitivity. In some cases, the corticomotor threshold is decreased early in the disease course as a result of corticomotor neuron hyperexcitability induced by glutamate. Later, the threshold increases, indicating a loss of UMN. In our experience, a decreased silent period duration appears to be the most sensitive parameter when using motor TMS in ALS. TMS is also a sensitive technique for investigating the corticobulbar tract, which is difficult to study by other methods. TMS is a widely available, painless and safe technique with a good sensitivity that can visualize both corticospinal and corticobulbar tract abnormalities. The sensitivity can be improved further by taking into account the several MEP parameters, including latency and cortical silent period decreased duration.

  12. Transcranial magnetic stimulation in the treatment of chronic widespread pain: a randomized controlled study.

    Science.gov (United States)

    Avery, David H; Zarkowski, Paul; Krashin, Daniel; Rho, Wang-Ku; Wajdik, Chandra; Joesch, Jutta M; Haynor, David R; Buchwald, Dedra; Roy-Byrne, Peter

    2015-03-01

    Our objective was to assess transcranial magnetic stimulation (TMS) in the treatment of chronic widespread pain. Nineteen participants were randomized into 2 groups: one group receiving active TMS (n = 7) and another group receiving sham stimulation (n = 11) applied to the left dorsolateral prefrontal cortex. During sham stimulation, subjects heard a sound similar to the sound heard by those receiving the active treatment and received an active electrical stimulus to the scalp. The stimulation protocol consisted of 15 sessions completed within a 4-week period. Blind assessments were done at baseline and after each 5 sessions followed by blind assessments at 1 week, 1 month, and 3 months after the last TMS sessions. The primary outcome variable was a pain measure, the Gracely Box Intensity Scale (BIRS). The percentage of subjects who guessed that they were receiving TMS was similar in the 2 groups. Both the TMS group and the sham group showed a statistically significant reduction in the BIRS scores from baseline during the acute phase of treatment and the follow-up phase. However, the TMS and sham groups did not differ in the change in the BIRS scores. Although some previous clinical studies and basic science studies of TMS in treating pain are promising, this study found no difference in the analgesic effect of TMS and sham stimulation. Future studies should use a sham condition that attempts to simulate the sound and sensation of the TMS stimulation. Stimulus location and other stimulus parameters should be explored in future studies.

  13. [Transcranial focused ultrasound: Neurological applications of magnetic resonance-guided high-intensity focused ultrasound].

    Science.gov (United States)

    Werner, B; Martin, E

    2015-11-01

    Ultrasound surgery uses the thermal effects of the absorption of high-intensity focused ultrasound to induce localized thermal ablation of diseased tissue. The clinical introduction in recent years was made possible by a better understanding of the interactions of ultrasound with biological structures and the resulting physiological changes, major advances in the design of ultrasound applicators and the development of imaging modalities for reliable guiding the interventions. Magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS) is especially appealing for applications in the brain where target volumes have to be accessed with high precision without inflicting collateral damage to surrounding healthy tissue. In 2013 a MRgFUS system was CE certified for the treatment of functional neurological disorders, such as chronic neuropathic pain and movement disorders. Currently, some 400 patients have been treated worldwide using this system, which is also undergoing clinical testing for the treatment of primary brain tumors and brain metastases. This article describes the technical basis of transcranial focused ultrasound neurosurgery and summarizes the current clinical experience of this new class of image-guided, non-invasive interventions.

  14. Field modeling for transcranial magnetic stimulation: A useful tool to understand the physiological effects of TMS?

    Science.gov (United States)

    Thielscher, Axel; Antunes, Andre; Saturnino, Guilherme B

    2015-01-01

    Electric field calculations based on numerical methods and increasingly realistic head models are more and more used in research on Transcranial Magnetic Stimulation (TMS). However, they are still far from being established as standard tools for the planning and analysis in practical applications of TMS. Here, we start by delineating three main challenges that need to be addressed to unravel their full potential. This comprises (i) identifying and dealing with the model uncertainties, (ii) establishing a clear link between the induced fields and the physiological stimulation effects, and (iii) improving the usability of the tools for field calculation to the level that they can be easily used by non-experts. We then introduce a new version of our pipeline for field calculations (www.simnibs.org) that substantially simplifies setting up and running TMS and tDCS simulations based on Finite-Element Methods (FEM). We conclude with a brief outlook on how the new version of SimNIBS can help to target the above identified challenges.

  15. Frontal and parietal transcranial magnetic stimulation (TMS) disturbs programming of saccadic eye movements.

    Science.gov (United States)

    Zangemeister, W H; Canavan, A G; Hoemberg, V

    1995-11-01

    Transcranial magnetic stimulation (TMS) of human motor cortex typically evoked motor responses. TMS has failed to elicit eye movements in humans, whereas prolongations of saccadic latency have been reported with TMS. In previous studied we demonstrated that saccades can be abolished or saccadic trajectories can be changed through TMS in the 100 msec before saccade onset. This effect was especially marked when TMS was applied parietally. TMS never influenced a saccade in flight. Simulations of predictive experimental saccades that were impaired through TMS of the frontal or parietal cortex demonstrated especially that the dynamics of small saccades were markedly influenced, resulting in a significant decrease in acceleration and amplitude, or an almost complete inhibition. The impact of inhibition through TMS was critically dependent on timing: early TMS (-70 msec) had a much larger inhibitory effect than late TMS (-20 msec) on experimental saccades. Differential timing of TMS in influencing the cortical control signal is demonstrated through simulations of a reciprocally innervated eye movement model that paralleled empirically determined changes in eye movement dynamics after real TMS. There is a reasonable match between the model and the experimental data. We conclude that the inhibitory action of a presaccadic disturbance, such as a TMS pulse, on saccadic programming is inversely related to timing and amplitude of the predicted saccade.

  16. Quantifying uncertainty in Transcranial Magnetic Stimulation - A high resolution simulation study in ICBM space.

    Science.gov (United States)

    Toschi, Nicola; Keck, Martin E; Welt, Tobias; Guerrisi, Maria

    2012-01-01

    Transcranial Magnetic Stimulation offers enormous potential for noninvasive brain stimulation. While it is known that brain tissue significantly "reshapes" induced field and charge distributions, most modeling investigations to-date have focused on single-subject data with limited generality. Further, the effects of the significant uncertainties which exist in the simulation (i.e. brain conductivity distributions) and stimulation (e.g. coil positioning and orientations) setup have not been quantified. In this study, we construct a high-resolution anisotropic head model in standard ICBM space, which can be used as a population-representative standard for bioelectromagnetic simulations. Further, we employ Monte-Carlo simulations in order to quantify how uncertainties in conductivity values propagate all the way to induced field and currents, demonstrating significant, regionally dependent dispersions in values which are commonly assumed "ground truth". This framework can be leveraged in order to quantify the effect of any type of uncertainty in noninvasive brain stimulation and bears relevance in all applications of TMS, both investigative and therapeutic.

  17. Determination of stimulation focality in heterogeneous head models during transcranial magnetic stimulation (TMS)

    Science.gov (United States)

    Lee, Erik; Hadimani, Ravi; Jiles, David

    2015-03-01

    Transcranial Magnetic Stimulation (TMS) is an increasingly popular tool used by both the scientific and medical community to understand and treat the brain. TMS has the potential to help people with a wide range of diseases such as Parkinson's, Alzheimer's, and PTSD, while currently being used to treat people with chronic, drug-resistant depression. Through computer simulations, we are able to see the electric field that TMS induces in anatomical human models, but there is no measure to quantify this electric field in a way that relates to a specific patient undergoing TMS therapy. We propose a way to quantify the focality of the induced electric field in a heterogeneous head model during TMS by relating the surface area of the brain being stimulated to the total volume of the brain being stimulated. This figure would be obtained by conducting finite element analysis (FEA) simulations of TMS therapy on a patient specific head model. Using this figure to assist in TMS therapy will allow clinicians and researchers to more accurately stimulate the desired region of a patient's brain and be more equipped to do comparative studies on the effects of TMS across different patients. This work was funded by the Carver Charitable Trust.

  18. Methods for estimating cortical motor representation size and location in navigated transcranial magnetic stimulation.

    Science.gov (United States)

    Julkunen, Petro

    2014-07-30

    Navigated transcranial magnetic stimulation (nTMS) is used for locating and outlining cortical representation areas, e.g., of motor function and speech. At present there are no standard methods of measuring the size of the cortical representation areas mapped with nTMS. The aim was to compare four computation methods for estimating muscle representation size and location for nTMS studies. The motor cortex of six subjects was mapped to outline the motor cortical representation of hand muscles. Four methods were compared to assess cortical representation size in nTMS. These methods included: (1) spline interpolation method, (2) convex hull method, which outlines all positive motor responses, (3) Voronoi tessellation method, which assigns a specific cortical area for each stimulus location, and (4) average point-area method, which computes an average representation area for each stimulus with the assumption of evenly spaced stimulus locations, i.e., the use of a grid. All applied methods demonstrated good repeatability in measuring muscle representation size and location, while the spline interpolation and the convex hull method demonstrated systematically larger representation areas (pmotor cortical muscle representation size and location with nTMS, e.g., to study cortical plasticity. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Onset Latency of Motor Evoked Potentials in Motor Cortical Mapping with Neuronavigated Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Kallioniemi, Elisa; Pitkänen, Minna; Säisänen, Laura; Julkunen, Petro

    2015-01-01

    Cortical motor mapping in pre-surgical applications can be performed using motor evoked potential (MEP) amplitudes evoked with neuronavigated transcranial magnetic stimulation. The MEP latency, which is a more stable parameter than the MEP amplitude, has not so far been utilized in motor mapping. The latency, however, may provide information about the stress in damaged motor pathways, e.g. compression by tumors, which cannot be observed from the MEP amplitudes. Thus, inclusion of this parameter could add valuable information to the presently used technique of MEP amplitude mapping. In this study, the functional cortical representations of first dorsal interosseous (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles were mapped in both hemispheres of ten healthy righthanded volunteers. The cortical muscle representations were evaluated by the area and centre of gravity (CoG) by using MEP amplitudes and latencies. As expected, the latency and amplitude CoGs were congruent and were located in the centre of the maps but in a few subjects, instead of a single centre, several loci with short latencies were observed. In conclusion, MEP latencies may be useful in distinguishing the cortical representation areas with the most direct pathways from those pathways with prolonged latencies. However, the potential of latency mapping to identify stressed motor tract connections at the subcortical level will need to be verified in future studies with patients.

  20. Effects of repetitive transcranial magnetic stimulation on masseter motor-neuron pool excitability.

    Science.gov (United States)

    Huang, Huang; Liu, Wei Cai; Song, Yu Han

    2017-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has been widely used to modulate the excitability of the cortical control of limbs muscles, but rarely in the cortical control of human masseter muscles. This study aims to investigate the effects of rTMS on masseter motor-neuron pool excitability in humans. A total of 20 healthy participants were selected and received a total of three rTMS sessions involving stimulation of the right masseter-motor complex: one session of 10-Hz rTMS, one session of 1-Hz rTMS and one session of sham rTMS at an intensity of 80% of the active motor threshold (AMT). The masseter AMT, motor-evoked potentials (MEPs), cortical-silent period (CSP), and short-interval intracortical inhibition (SICI) were measured before and after each rTMS session. The masseter SICI was significantly decreased following 10-Hz rTMS, with no significant changes in AMT, MEPs or CSP. No significant differences in masseter AMT, MEPs, CSP or SICI were observed in either the 1-Hz, or sham rTMS groups. The present findings demonstrate that high-frequency rTMS increases masseter motor-neuron pool excitability. Copyright © 2016. Published by Elsevier Ltd.

  1. Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation.

    Science.gov (United States)

    Tapia, Evelina; Beck, Diane M

    2014-01-01

    A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness.

  2. Sensory tricks and brain excitability in cervical dystonia: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Amadio, Stefano; Houdayer, Elise; Bianchi, Francesca; Tesfaghebriel Tekle, Habtom; Urban, Ivan Pietro; Butera, Calogera; Guerriero, Roberta; Cursi, Marco; Leocani, Letizia; Comi, Giancarlo; Del Carro, Ubaldo

    2014-08-01

    Sensory tricks such as touching the face with fingertips often improve cervical dystonia [CD]. This study is to determine whether sensory tricks modulate motor cortex excitability, assessed by paired-pulse transcranial magnetic stimulation [p-pTMS]. Eight patients with rotational CD underwent p-pTMS, at rest and when the sensory trick was applied. To test intracortical inhibition [ICI] and facilitation [ICF], the amplitude ratio between conditioned and unconditioned cortical motor evoked potentials was measured at several interstimulus intervals (ISI 1, 3, 15, and 20 ms) and compared with controls mimicking patients' sensory tricks. At rest, a significant ICF enhancement was found at ISIs 15 through 20 in patients compared with controls, whereas no significant ICI changes were observed. Sensory tricks significantly reduced the abnormal ICF in patients and did not induce any change in controls. In our CD patients, sensory tricks seem to improve dystonia through an inhibitory effect on motor cortex excitability. © 2014 International Parkinson and Movement Disorder Society.

  3. Transcranial magnetic stimulation techniques to study the somatosensory system: research applications.

    Science.gov (United States)

    Staines, W Richard; Bolton, David A E

    2013-01-01

    The introduction of brain stimulation research techniques such as transcranial magnetic stimulation (TMS) has greatly advanced the understanding of the somatosensory system in humans. Over the last several years, several studies have focused on applying TMS in a variety of contexts to alter transiently the excitability of the somatosensory cortex or regions that project to it and exert some control over its activity in specific behavioral contexts. Specific foci that are discussed in this chapter are methods of repetitive TMS, including theta-burst protocols, delivered to the primary somatosensory cortex that have been shown to affect behavioral indices of somatic sensation such as tactile perception. Similar stimulation techniques can also be applied to distant areas that interact with and modulate activity in somatosensory cortex (i.e., attentional or motor networks). For example, suppression of the dorsolateral prefrontal cortex modifies the attention-modulation of somatosensory information in modality-specific cortices. Overall this chapter is focused on understanding the interaction of activity in systems that function with the somatosensory system in behavioral contexts. These include systems such as those that control attention, whether sustained or selective between sensory modalities, or those that control movement based on targets present in other sensory systems. © 2013 Elsevier B.V. All rights reserved.

  4. [Transcranial magnetic therapy in the complex treatment of affective disorders in patients with alcoholism].

    Science.gov (United States)

    Staroverov, A T; Vil'ianov, V B; Raĭgorodskiĭ, Iu M; Rogozina, M A

    2008-01-01

    A main group--32 patients receiving transcranial magnetic therapy (TMT) in addition to the basic treatment (nootrops, hepatoprotectors, vitamins/minerals etc)--was compared to a control group (30 patients) receiving placebo instead of TMT. All patients, aged from 35 to 64 years, had the second stage of alcoholism with illness duration from 4 to 12 years and were in the postabstinent state at the moment of treatment. The TMT course included 10 daily sessions with a 10-20 min exposure. A somatic, neurological and instrumental study, including cardiointervalography, electroencephalography, assessment of autonomic system state and psychometric scales for depression and anxiety, was conducted before, during and after the therapy. The improvement of health, mood and sleep, increase of tolerability to physical loading and reduction of alcohol craving were observed after TMT in 75% of patients in the main group and in 30% in the control one. The improvement of patient's state was correlated with the data of the paraclinical study (electrophysiological parameters of the autonomic nervous system and psychometric scales scores).

  5. Factor Analysis of Low-Frequency Repetitive Transcranial Magnetic Stimulation to the Temporoparietal Junction for Tinnitus

    Science.gov (United States)

    Li, Bei; Wang, Meiye; Li, Ming; Yin, Shankai

    2016-01-01

    Objectives. We investigated factors that contribute to suppression of tinnitus after repetitive transcranial magnetic stimulation (rTMS). Methods. A total of 289 patients with tinnitus underwent active 1 Hz rTMS in the left temporoparietal region. A visual analog scale (VAS) was used to assess tinnitus loudness. All participants were interviewed regarding age, gender, tinnitus duration, laterality and pitch, audiometric parameters, sleep, and so forth. The resting motor thresholds (RMTs) were measured in all patients and 30 age- and gender-matched volunteers. Results. With respect to different factors that contribute to tinnitus suppression, we found improvement in the following domains: shorter duration, normal hearing (OR: 3.25, 95%CI: 2.01–5.27, p = 0.001), and without sleep disturbance (OR: 2.51, 95%CI: 1.56–4.1, p = 0.005) adjusted for age and gender. The patients with tinnitus lasting less than 1 year were more likely to show suppression of tinnitus (OR: 2.77, 95%CI: 1.48–5.19, p = 0.002) compared to those with tinnitus lasting more than 5 years. Tinnitus patients had significantly lower RMTs compared with healthy volunteers. Conclusion. Active low-frequency rTMS results in a significant reduction in the loudness of tinnitus. Significant tinnitus suppression was shown in subjects with shorter tinnitus duration, with normal hearing, and without sleep disturbance. PMID:27847647

  6. Corticospinal facilitation during observation of graspable objects: a transcranial magnetic stimulation study.

    Directory of Open Access Journals (Sweden)

    Michele Franca

    Full Text Available In 1979, Gibson first advanced the idea that the sight of graspable objects automatically activates in the observer the repertoire of actions necessary to interact with them, even in the absence of any intention to act ("affordance effect". The neurophysiological substrate of this effect was later identified in a class of bimodal neurons, the so-called "canonical" neurons, located within monkey premotor cortex. In humans, even if different behavioral studies supported the existence of affordance effect, neurophysiological investigations exploring its neural substrates showed contradictory results. Here, by means of Transcranial Magnetic Stimulation (TMS, we explored the time-course of the "affordance effect" elicited by the observation of everyday-life graspable objects on motor cortex of resting observers. We recorded motor evoked potentials (MEP from three intrinsic hand muscles (two "synergic" for grasping, OP and FDI and one "neutral", ADM. We found that objects' vision determined an increased excitability at 120 milliseconds after their presentation. Moreover, this modulation was proved to be specific to the cortical representations of synergic muscles. From an evolutionary perspective, this timing perfectly fits with a fast recruitment of the motor system aimed at rapidly and accurately choosing the appropriate motor plans in a competitive environment filled with different opportunities.

  7. Neuroimaging Mechanisms of Therapeutic Transcranial Magnetic Stimulation for Major Depressive Disorder.

    Science.gov (United States)

    Philip, Noah S; Barredo, Jennifer; Aiken, Emily; Carpenter, Linda L

    2018-03-01

    Research into therapeutic transcranial magnetic stimulation (TMS) for major depression has dramatically increased in the last decade. Understanding the mechanism of action of TMS is crucial to improve efficacy and develop the next generation of therapeutic stimulation. Early imaging research provided initial data supportive of widely held assumptions about hypothesized inhibitory or excitatory consequences of stimulation. Early work also indicated that while TMS modulated brain activity under the stimulation site, effects at deeper regions, in particular, the subgenual anterior cingulate cortex, were associated with clinical improvement. Concordant with earlier findings, functional connectivity studies also demonstrated that clinical improvements were related to changes distal, rather than proximal, to the site of stimulation. Moreover, recent work suggests that TMS modulates and potentially normalizes functional relationships between neural networks. An important observation that emerged from this review is that similar patterns of connectivity changes are observed across studies regardless of TMS parameters. Though promising, we stress that these imaging findings must be evaluated cautiously given the widespread reliance on modest sample sizes and little implementation of statistical validation. Additional limitations included use of imaging before and after a course of TMS, which provided little insight into changes that might occur during the weeks of stimulation. Furthermore, as studies to date have focused on depression, it is unclear whether our observations were related to mechanisms of action of TMS for depression or represented broader patterns of functional brain changes associated with clinical improvement. Published by Elsevier Inc.

  8. Effect of repetitive transcranial magnetic stimulation on rectal function and emotion in humans

    International Nuclear Information System (INIS)

    Aizawa, Yuuichi; Morishita, Joe; Kano, Michiko; Mori, Takayuki; Izumi, Shin-ichi; Kanazawa, Motoyori; Fukudo, Shin; Tsutsui, Kenichiro; Iijima, Toshio

    2011-01-01

    A previous brain imaging study demonstrated activation of the right dorsolateral prefrontal cortex (DLPFC) during visceral nociception, and this activation was associated with anxiety. We hypothesized that functional modulation of the right DLPFC by repetitive transcranial magnetic stimulation (rTMS) can reveal the actual role of right DLPFC in brain-gut interactions in humans. Subjects were 11 healthy males aged 23.5±1.4 (mean±spin echo (SE)) years. Viscerosensory evoked potential (VEP) with sham (0 mA) or actual (30 mA) electrical stimulation (ES) of the rectum was taken after sham, low frequency rTMS at 0.1 Hz, and high frequency rTMS at 10 Hz to the right DLPFC. Rectal tone was measured with a rectal barostat. Visceral perception and emotion were analyzed using an ordinate scale, rectal barostat, and VEP. Low frequency rTMS significantly reduced anxiety evoked by ES at 30 mA (p<0.05). High frequency rTMS-30 mA ES significantly produced more phasic volume events than sham rTMS-30 mA ES (p<0.05). We successfully modulated the gastrointestinal function of healthy individuals through rTMS to the right DLPFC. Thus, rTMS to the DLPFC appears to modulate the affective, but not direct, component of visceral perception and motility of the rectum. (author)

  9. Observation of interactive behavior increases corticospinal excitability in humans: A transcranial magnetic stimulation study.

    Science.gov (United States)

    Aihara, Tsuyoshi; Yamamoto, Shinji; Mori, Hirotaka; Kushiro, Keisuke; Uehara, Shintaro

    2015-11-01

    In humans, observation of others' behaviors increases corticospinal excitability (CSE), which is interpreted in the contexts of motor resonance and the "mirror neuron system" (MNS). It has been suggested that observation of another individual's behavior manifests an embodied simulation of his/her mental state through the MNS. Thus, the MNS may involve understanding others' intentions of behaviors, thoughts, and emotions (i.e., social cognition), and may therefore exhibit a greater response when observing human-interactive behaviors that require a more varied and complex understanding of others. In the present study, transcranial magnetic stimulation was applied to the primary motor cortex of participants observing human-interactive behaviors between two individuals (c.f. one person reaching toward an object in another person's hand) and non-interactive individual behavior (c.f. one person reaching toward an object on a dish). We carefully controlled the kinematics of behaviors in these two conditions to exclude potential effects of MNS activity changes associated with kinematic differences between visual stimuli. Notably, motor evoked potentials, that reflect CSE, from the first dorsal interosseous muscle exhibited greater amplitude when the participants observed interactive behaviors than when they observed non-interactive behavior. These results provide neurophysiological evidence that the MNS is activated to a greater degree during observation of human-interactive behaviors that contain additional information about the individuals' mental states, supporting the view that the MNS plays a critical role in social cognition in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Calcium dependent plasticity applied to repetitive transcranial magnetic stimulation with a neural field model.

    Science.gov (United States)

    Wilson, M T; Fung, P K; Robinson, P A; Shemmell, J; Reynolds, J N J

    2016-08-01

    The calcium dependent plasticity (CaDP) approach to the modeling of synaptic weight change is applied using a neural field approach to realistic repetitive transcranial magnetic stimulation (rTMS) protocols. A spatially-symmetric nonlinear neural field model consisting of populations of excitatory and inhibitory neurons is used. The plasticity between excitatory cell populations is then evaluated using a CaDP approach that incorporates metaplasticity. The direction and size of the plasticity (potentiation or depression) depends on both the amplitude of stimulation and duration of the protocol. The breaks in the inhibitory theta-burst stimulation protocol are crucial to ensuring that the stimulation bursts are potentiating in nature. Tuning the parameters of a spike-timing dependent plasticity (STDP) window with a Monte Carlo approach to maximize agreement between STDP predictions and the CaDP results reproduces a realistically-shaped window with two regions of depression in agreement with the existing literature. Developing understanding of how TMS interacts with cells at a network level may be important for future investigation.

  11. Online repetitive transcranial magnetic stimulation (TMS) to the parietal operculum disrupts haptic memory for grasping.

    Science.gov (United States)

    Cattaneo, Luigi; Maule, Francesca; Tabarelli, Davide; Brochier, Thomas; Barchiesi, Guido

    2015-11-01

    The parietal operculum (OP) contains haptic memory on the geometry of objects that is readily transferrable to the motor cortex but a causal role of OP in memory-guided grasping is only speculative. We explored this issue by using online high-frequency repetitive transcranial magnetic stimulation (rTMS). The experimental task was performed by blindfolded participants acting on objects of variable size. Trials consisted in three phases: haptic exploration of an object, delay, and reach-grasp movement onto the explored object. Motor performance was evaluated by the kinematics of finger aperture. Online rTMS was applied to the left OP region separately in each of the three phases of the task. The results showed that rTMS altered grip aperture only when applied in the delay phase to the OP. In a second experiment a haptic discriminative (match-to-sample) task was carried out on objects similar to those used in the first experiment. Online rTMS was applied to the left OP. No psychophysical effects were induced by rTMS on the detection of explicit haptic object size. We conclude that neural activity in the OP region is necessary for proficient memory-guided haptic grasping. The function of OP seems to be critical while maintaining the haptic memory trace and less so while encoding it or retrieving it. © 2015 Wiley Periodicals, Inc.

  12. Repetitive transcranial magnetic stimulation as a neuropsychiatric tool: present status and future potential.

    Science.gov (United States)

    Post, R M; Kimbrell, T A; McCann, U D; Dunn, R T; Osuch, E A; Speer, A M; Weiss, S R

    1999-03-01

    Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising therapeutic intervention in the treatment of affective disorders. The differences in the type of electrical stimulation required for therapeutic efficacy by rTMS and electroconvulsive therapy (ECT) are discussed. In contrast to ECT, rTMS would not appear to require the generation of a major motor seizure to achieve therapeutic efficacy. Accordingly, it carries the potentially important clinical advantages of not requiring anesthesia and of avoiding side effects such as transient memory loss. Preclinical studies on long-term potentiation (LTP) and long-term depression (LTD) in hippocampal and amygdala slices, as well as clinical data from neuroimaging studies, have provided encouraging clues for potential frequency-dependent effects of rTMS. Preliminary evidence from position emission tomography (PET) scans suggests that higher frequency (20 Hz) stimulation may increase brain glucose metabolism in a transsynaptic fashion, whereas lower frequency (1 Hz) stimulation may decrease it. Therefore, the ability of rTMS to control the frequency as well as the location of stimulation, in addition to its other advantages, has opened up new possibilities for clinical explorations and treatments of neuropsychiatric conditions.

  13. Repetitive transcranial magnetic stimulation for rehabilitation of poststroke dysphagia: A randomized, double-blind clinical trial.

    Science.gov (United States)

    Du, Juan; Yang, Fang; Liu, Ling; Hu, Jingze; Cai, Biyang; Liu, Wenhua; Xu, Gelin; Liu, Xinfeng

    2016-03-01

    This randomized, sham-controlled, double-blind study was conducted to investigate the effects of high-frequency versus low-frequency repetitive transcranial magnetic stimulation (rTMS) on patients with poststroke dysphagia during early rehabilitation. Forty patients with poststroke dysphagia were randomized to receive five daily sessions of sham, 3-Hz ipsilesional, or 1-Hz contralesional rTMS. Swallowing function, the severity of stroke and functional disability, and cortical excitability were examined before, immediately after five daily sessions, as well as the first, second, and third month after the last session. At baseline, no significant differences between groups were observed in terms of demographic and clinical rating scales. However, a significantly greater improvement in swallowing function as well as functional disability was observed after real rTMS when compared with sham rTMS, which remained 3 months after the end of the treatment sessions. In addition, 1-Hz rTMS increased cortical excitability of the affected hemisphere and decreased that of the non-affected hemisphere; however, 3-Hz rTMS only increased cortical excitability of the affected hemisphere. rTMS (both high and low frequency) improved swallowing recovery in patients with poststroke dysphagia, and the effects lasted for at least 3 months. rTMS appears to be a beneficial therapeutic modality for patients with dysphagia during the early phase of stroke. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  14. Poststroke dysphagia rehabilitation by repetitive transcranial magnetic stimulation: a noncontrolled pilot study.

    Science.gov (United States)

    Verin, E; Leroi, A M

    2009-06-01

    Poststroke dysphagia is frequent and significantly increases patient mortality. In two thirds of cases there is a spontaneous improvement in a few weeks, but in the other third, oropharyngeal dysphagia persists. Repetitive transcranial magnetic stimulation (rTMS) is known to excite or inhibit cortical neurons, depending on stimulation frequency. The aim of this noncontrolled pilot study was to assess the feasibility and the effects of 1-Hz rTMS, known to have an inhibitory effect, on poststroke dysphagia. Seven patients (3 females, age = 65 +/- 10 years), with poststroke dysphagia due to hemispheric or subhemispheric stroke more than 6 months earlier (56 +/- 50 months) diagnosed by videofluoroscopy, participated in the study. rTMS at 1 Hz was applied for 20 min per day every day for 5 days to the healthy hemisphere to decrease transcallosal inhibition. The evaluation was performed using the dysphagia handicap index and videofluoroscopy. The dysphagia handicap index demonstrated that the patients had mild oropharyngeal dysphagia. Initially, the score was 43 +/- 9 of a possible 120 which decreased to 30 +/- 7 (p dysphagia and improves swallowing coordination. Our results now need to be confirmed by a randomized controlled study with a larger patient population.

  15. Lateralized effect of rapid-rate transcranial magnetic stimulation of the prefrontal cortex on mood.

    Science.gov (United States)

    Pascual-Leone, A; Catalá, M D; Pascual-Leone Pascual, A

    1996-02-01

    We studied the effects of rapid-rate transcranial magnetic stimulation (rTMS) of different scalp positions on mood. Ten normal volunteers rated themselves before and after rTMS on five analog scales labeled "Tristeza" (Sadness), "Ansiedad" (Anxiety), "Alegria" (Happiness), "Cansancio" (Tiredness), and "Dolor/Malestar" (Pain/Discomfort). rTMS was applied to the right lateral prefrontal, left prefrontal, or midline frontal cortex in trains of 5 seconds' duration at 10 Hz and 110% of the subject's motor threshold intensity. Each stimulation position received 10 trains separated by a 25-second pause. No clinically apparent mood changes were evoked by rTMS to any of the scalp positions in any subject. However, left prefrontal rTMS resulted in a significant increase in the Sadness ratings (Tristeza) and a significant decrease in the Happiness ratings ("Alegria") as compared with right prefrontal and midfrontal cortex stimulation. These results show differential effects of rTMS of left and right prefrontal cortex stimulation on mood and illustrate the lateralized control of mood in normal volunteers.

  16. Influence of repetitive transcranial magnetic stimulation on tibialis anterior activity during walking in humans.

    Science.gov (United States)

    Rambour, Mélanie; Caux-Dedeystère, Alexandre; Devanne, Hervé; Defebvre, Luc; Derambure, Philippe; Delval, Arnaud

    2016-03-11

    To determine whether or not modulation of the excitability of the M1 region controlling the lower limb (using repetitive transcranial magnetic stimulation; TMS) would change the TA's activity during gait and the effect of aging on this change. In three separate sessions, participants underwent different repetitive TMS (rTMS) protocols (sham stimulation, intermittent theta-burst stimulation (TBS) and continuous TBS) delivered over the M1 region controlling the lower limb muscles, using a focal, figure-of-eight coil. Before and after rTMS, the TA's activity was recorded using surface electrodes while participants walked at a freely chosen speed and at an imposed speed on a treadmill. Cortical excitability was assessed by characterizing input-output (IO) curves, after fitting the relationship between motor evoked potential amplitude and stimulus intensity with a Boltzmann sigmoidal equation. We did not observe any effects of rTMS in terms of TA activation during locomotion, gait parameters or IO curves in either healthy young adults or elderly adults. Elderly patients presented lower excitability of cortical TA representation area. Modulation of TA activity by TBS was ineffective contrary to what is observed for upper limbs. Interindividual variability in the effects of rTMS on TA activation, activation of the TA before the rTMS and/or differences in the depth of the cortical representation of the TA could have influenced the results and should be taken into account for further studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Accelerated high-frequency repetitive transcranial magnetic stimulation enhances motor activity in rats.

    Science.gov (United States)

    El Arfani, Anissa; Parthoens, Joke; Demuyser, Thomas; Servaes, Stijn; De Coninck, Mattias; De Deyn, Peter Paul; Van Dam, Debby; Wyckhuys, Tine; Baeken, Chris; Smolders, Ilse; Staelens, Steven

    2017-04-07

    High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) is currently accepted as an evidence-based treatment option for treatment-resistant depression (TRD). Additionally, HF-rTMS showed beneficial effects on psychomotor retardation in patients. The classical HF-rTMS paradigms however are unlikely to replace electroconvulsive therapy, a more potent alternative for TRD albeit with important side-effects. Therefore, recent studies have investigated 'accelerated' HF-rTMS protocols demonstrating promising clinical responses in patients with TRD. Since the neuronal effects of accelerated HF-rTMS are underinvestigated, we evaluate here the possible metabolic and neurochemical effects of this treatment alternative. More specifically, we measured the effect on brain glucose metabolism and monoamines/metabolites, as well as on the spontaneous motor activity in rats. We found that brain glucose metabolism and monoamines remained generally unaffected after accelerated HF-rTMS, with the exception of reduced total striatal 5-hydroxyindolacetic acid (a metabolite of serotonin) levels. Interestingly, when compared to sham stimulation, the velocity, the total distance traveled as well as the percentage of movement, as measured by the open-field test, were significantly enhanced after accelerated HF-rTMS showing an increased motor activity. Our current results indicate that the accelerated HF-rTMS-induced increase in motor activity in rats, may be related to the striatal neurochemical effect. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Release of premotor activity after repetitive transcranial magnetic stimulation of prefrontal cortex.

    Science.gov (United States)

    Gangitano, Massimo; Mottaghy, Felix M; Pascual-Leone, Alvaro

    2008-01-01

    In the present study we aimed to explore by means of repetitive transcranial magnetic stimulation (rTMS) the reciprocal influences between prefrontal cortex (PFC) and premotor cortex (PMC). Subjects were asked to observe on a computer monitor different pictures representing manipulations of different kind of tools. They had to produce a movement (go condition) or to keep the resting position (no-go condition) at the appearance of different cue signals represented by different colors shown alternatively on the hands manipulating the tools or on the picture background. Motor evoked potentials (MEPs) were collected at the offset of the visual stimuli before and after a 10 minute, 1 Hz rTMS train applied to the dorsolateral PFC (Experiment 1), to the PMC (Experiment 2) or to the primary motor cortex (Experiment 3). Following rTMS to the PFC, MEPs increased in the go condition when the cue for the go command was presented on the hand. In contrast, following rTMS to the PMC, in the same condition, MEPs were decreased. rTMS to the primary motor cortex did not produce any modulation. Results are discussed according to the presence of a visual-motor matching system in the PMC and to the role of the PFC in the attention-related processes. We hypothesize that the perceptual analysis for action selection within the PFC was modulated by rTMS and its temporary functional inactivation in turn influenced the premotor areas for motor programming.

  19. Chronic treatment with repetitive transcranial magnetic stimulation inhibits seizure induction by electroconvulsive shock in rats.

    Science.gov (United States)

    Fleischmann, A; Hirschmann, S; Dolberg, O T; Dannon, P N; Grunhaus, L

    1999-03-15

    Studies in laboratory animals suggest that repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive shock (ECS) increase seizure inhibition acutely. This study was designed to explore whether chronic rTMS would also have seizure inhibition properties. To this purpose we administered rTMS (Magstim Rapid) and sham rTMS twice daily (2.5 T, 4-sec train duration, 20 Hz) to two groups of 10 rats for 16 days. The rTMS coil was a 50-mm figure-8 coil held directly over the rat's head. Raters were blind to experimental groups. On days 11, 17, and 21 (5 days after the last rTMS) ECS was administered with a Siemens convulsator using three electrical charge levels. Variables examined were the presence or absence of seizures and seizure length (measured from the initiation of the tonic contraction until the end of the limb movement). At day 11 rTMS had no effect on seizures, and both rTMS and sham rTMS animals convulsed equally. At day 17, however, rTMS-treated animals convulsed significantly less (both at presence/absence of seizures, and at seizure length) than sham rTMS animals. At day 21 the effects of rTMS had disappeared. These findings suggest that rTMS administered chronically leads to changes in seizure threshold similar to those reported for ECS and ECT; however, these effects were short-lived.

  20. Attention modulates specific motor cortical circuits recruited by transcranial magnetic stimulation.

    Science.gov (United States)

    Mirdamadi, J L; Suzuki, L Y; Meehan, S K

    2017-09-17

    Skilled performance and acquisition is dependent upon afferent input to motor cortex. The present study used short-latency afferent inhibition (SAI) to probe how manipulation of sensory afference by attention affects different circuits projecting to pyramidal tract neurons in motor cortex. SAI was assessed in the first dorsal interosseous muscle while participants performed a low or high attention-demanding visual detection task. SAI was evoked by preceding a suprathreshold transcranial magnetic stimulus with electrical stimulation of the median nerve at the wrist. To isolate different afferent intracortical circuits in motor cortex SAI was evoked using either posterior-anterior (PA) or anterior-posterior (PA) monophasic current. In an independent sample, somatosensory processing during the same attention-demanding visual detection tasks was assessed using somatosensory-evoked potentials (SEP) elicited by median nerve stimulation. SAI elicited by AP TMS was reduced under high compared to low visual attention demands. SAI elicited by PA TMS was not affected by visual attention demands. SEPs revealed that the high visual attention load reduced the fronto-central P20-N30 but not the contralateral parietal N20-P25 SEP component. P20-N30 reduction confirmed that the visual attention task altered sensory afference. The current results offer further support that PA and AP TMS recruit different neuronal circuits. AP circuits may be one substrate by which cognitive strategies shape sensorimotor processing during skilled movement by altering sensory processing in premotor areas. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. Correlation Networks for Identifying Changes in Brain Connectivity during Epileptiform Discharges and Transcranial Magnetic Stimulation

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    Elsa Siggiridou

    2014-07-01

    Full Text Available The occurrence of epileptiform discharges (ED in electroencephalographic (EEG recordings of patients with epilepsy signifies a change in brain dynamics and particularly brain connectivity. Transcranial magnetic stimulation (TMS has been recently acknowledged as a non-invasive brain stimulation technique that can be used in focal epilepsy for therapeutic purposes. In this case study, it is investigated whether simple time-domain connectivity measures, namely cross-correlation and partial cross-correlation, can detect alterations in the connectivity structure estimated from selected EEG channels before and during ED, as well as how this changes with the application of TMS. The correlation for each channel pair is computed on non-overlapping windows of 1 s duration forming weighted networks. Further, binary networks are derived by thresholding or statistical significance tests (parametric and randomization tests. The information for the binary networks is summarized by statistical network measures, such as the average degree and the average path length. Alterations of brain connectivity before, during and after ED with or without TMS are identified by statistical analysis of the network measures at each state.

  2. Reorganization of Motor Representations in Patients with Brain Lesions: A Navigated Transcranial Magnetic Stimulation Study.

    Science.gov (United States)

    Bulubas, Lucia; Sollmann, Nico; Tanigawa, Noriko; Zimmer, Claus; Meyer, Bernhard; Krieg, Sandro M

    2018-03-01

    This is an explorative study applying presurgical navigated transcranial magnetic stimulation (nTMS) to investigate the spatial distributions of motor sites to reveal tumor-induced brain plasticity in patients with brain tumors. We analyzed nTMS-based motor maps derived from presurgical mapping of 100 patients with motor eloquently located brain tumors (tumors in the frontal lobe, the precentral gyrus [PrG], the postcentral gyrus [PoG], the remaining parietal lobe, or the temporal lobe). Based on these motor maps, we systematically investigated changes in motor evoked potential (MEP) counts among 4 gyri (PrG, PoG, medial frontal gyrus, and superior frontal gyrus) between subgroups of patients according to the tumor location in order to depict the tumor's influence on reorganization. When comparing patients with different tumor locations, high MEP counts were elicited less frequently by stimulating the PrG in patients with tumors directly affecting the PrG (p reorganization is not likely to induce a shift of motor function from the PrG to adjacent regions but rather leads to a reorganization within anatomical constraints, such as of the PoG. Thus, presurgical nTMS-based motor mapping sensitively depicted the tumor-induced plasticity of the motor cortex.

  3. [Transcranial magnetic stimulation (TMS), inhibition processes and attention deficit/hyperactivity disorder (ADHD) - an overview].

    Science.gov (United States)

    Hoegl, Thomas; Bender, Stephan; Buchmann, Johannes; Kratz, Oliver; Moll, Gunther H; Heinrich, Hartmut

    2014-11-01

    Motor system excitability can be tested by transcranial magnetic stimulation CFMS). In this article, an overview of recent methodological developments and research findings related to attention deficit/hyperactivity disorder (ADHD) is provided. Different TMS parameters that reflect the function of interneurons in the motor cortex may represent neurophysiological markers of inhibition in ADHD, particularly the so-called intracortical inhibition. In children with a high level of hyperactivity and impulsivity, intracortical inhibition was comparably low at rest as shortly before the execution of a movement. TMS-evoked potentials can also be measured in the EEG so that investigating processes of excitability is not restricted to motor areas in future studies. The effects of methylphenidate on motor system excitability may be interpreted in the sense of a 'fine-tuning' with these mainly dopaminergic effects also depending on genetic parameters (DAT1 transporter). A differentiated view on the organization of motor control can be achieved by a combined analysis of TMS parameters and event-related potentials. Applying this bimodal approach, strong evidence for a deviant implementation of motor control in children with ADHD and probably compensatory mechanisms (with involvement of the prefrontal cortex) was obtained. These findings, which contribute to a better understanding of hyperactivity/impulsivity, inhibitory processes and motor control in ADHD as well as the mechanisms of medication, underline the relevance of TMS as a neurophysiological method in ADHD research.

  4. Test-retest reliability of single and paired pulse transcranial magnetic stimulation parameters in healthy subjects.

    Science.gov (United States)

    Hermsen, A M; Haag, A; Duddek, C; Balkenhol, K; Bugiel, H; Bauer, S; Mylius, V; Menzler, K; Rosenow, F

    2016-03-15

    To determine the influence of different factors on test-retest reliability of frequently used transcranial magnetic stimulation (TMS) parameters while controlling for potential confounders in healthy subjects. TMS was applied in 93 healthy volunteers (61% male) twice (mean retest interval of 34.0 ± 25.6 (SD) days) between 7 am and 2 pm by four investigators (sessions n investigator A=47, investigator B=95, investigator C=28, investigator D=16). Women were assessed in their follicular phase. Test stimulus (TS), resting motor threshold (RMT), short latency intracortical inhibition (SICI), intracortical facilitation (ICF) and cortical silent period (SCP) were analyzed. Good test-retest reliabilities were observed for TS (r=.880) and RMT (r=.826), moderate for visual and automated analyzed CSP durations (resp. r=.466, r=.486), and poor for ICF (r=-.159). Reliable change indexes are reported. Gender (e.g. automated CSP women: r=.538 vs. men: r=.422), re-test interval and method of CSP-analysis did not influence reliabilities. In a large sample of healthy volunteers we found good to moderate test-retest reliabilities in all but one TMS-parameter. Automated analysis of the CSP did not prove to be more reliable than visual determination. This study contains analyses of re-test reliability in TMS considering several confounding factors. For the first time it presents reliable change indices for all frequently used TMS parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Low frequency repetitive transcranial magnetic stimulation improves motor dysfunction after cerebral infarction

    Directory of Open Access Journals (Sweden)

    Zhi-yong Meng

    2017-01-01

    Full Text Available Low frequency (≤ 1 Hz repetitive transcranial magnetic stimulation (rTMS can affect the excitability of the cerebral cortex and synaptic plasticity. Although this is a common method for clinical treatment of cerebral infarction, whether it promotes the recovery of motor function remains controversial. Twenty patients with cerebral infarction combined with hemiparalysis were equally and randomly divided into a low frequency rTMS group and a control group. The patients in the low frequency rTMS group were given 1-Hz rTMS to the contralateral primary motor cortex with a stimulus intensity of 90% motor threshold, 30 minutes/day. The patients in the control group were given sham stimulation. After 14 days of treatment, clinical function scores (National Institute of Health Stroke Scale, Barthel Index, and Fugl-Meyer Assessment improved significantly in the low frequency rTMS group, and the effects were better than that in the control group. We conclude that low frequency (1 Hz rTMS for 14 days can help improve motor function after cerebral infarction.

  6. Low frequency repetitive transcranial magnetic stimulation improves motor dysfunction after cerebral infarction.

    Science.gov (United States)

    Meng, Zhi-Yong; Song, Wei-Qun

    2017-04-01

    Low frequency (≤ 1 Hz) repetitive transcranial magnetic stimulation (rTMS) can affect the excitability of the cerebral cortex and synaptic plasticity. Although this is a common method for clinical treatment of cerebral infarction, whether it promotes the recovery of motor function remains controversial. Twenty patients with cerebral infarction combined with hemiparalysis were equally and randomly divided into a low frequency rTMS group and a control group. The patients in the low frequency rTMS group were given 1-Hz rTMS to the contralateral primary motor cortex with a stimulus intensity of 90% motor threshold, 30 minutes/day. The patients in the control group were given sham stimulation. After 14 days of treatment, clinical function scores (National Institute of Health Stroke Scale, Barthel Index, and Fugl-Meyer Assessment) improved significantly in the low frequency rTMS group, and the effects were better than that in the control group. We conclude that low frequency (1 Hz) rTMS for 14 days can help improve motor function after cerebral infarction.

  7. Clinical repetitive transcranial magnetic stimulation for veterans with major depressive disorder.

    Science.gov (United States)

    Kozel, F Andrew; Hernandez, Michael; Van Trees, Kimberly; Phillips, Sean; Hashimie, Jaffrey; Weisman, Mark; Obregon, Demian; Sanchez, Deborah L; Catalano, Glenn; Schultz, Susan K

    2017-11-01

    Repetitive transcranial magnetic stimulation (TMS) is a relatively new treatment modality for patients with major depressive disorder (MDD). Numerous studies have demonstrated the efficacy of TMS for MDD in the general population. However, there is limited information regarding clinical outcomes among veterans receiving TMS for MDD. The clinical outcome and characteristics of all veterans with MDD who were treated with TMS as outpatients at the James A. Haley Veterans' Hospital from October 2013 to December 2016 were assessed. Among 40 patients who received TMS, there was a significant improvement of depressive symptoms using the Quick Inventory of Depressive Symptomatology-Self-Report (45% response, 20% remission) and the Montgomery-Åsberg Depression Rating Scale (61.9% response, 42.9% remission). In addition to significant improvement in depressive symptoms, self-report of anxiety symptoms and function significantly improved. TMS was generally well tolerated, with only a small percentage of patients discontinuing treatment due to side effects. No seizures or persistent adverse effects were observed or reported. TMS is an effective and well-tolerated option for MDD in a veteran population with significant treatment resistance and multiple comorbidities.

  8. Repetitive Transcranial Magnetic Stimulation Improves Handwriting in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Bubblepreet K. Randhawa

    2013-01-01

    Full Text Available Background. Parkinson disease (PD is characterized by hypometric movements resulting from loss of dopaminergic neurons in the substantia nigra. PD leads to decreased activation of the supplementary motor area (SMA; the net result of these changes is a poverty of movement. The present study determined the impact of 5 Hz repetitive transcranial magnetic stimulation (rTMS over the SMA on a fine motor movement, handwriting (writing cursive “l”s, and on cortical excitability, in individuals with PD. Methods. In a cross-over design, ten individuals with PD were randomized to receive either 5 Hz or control stimulation over the SMA. Immediately following brain stimulation right handed writing was assessed. Results. 5 Hz stimulation increased vertical size of handwriting and diminished axial pressure. In addition, 5 Hz rTMS significantly decreased the threshold for excitability in the primary motor cortex. Conclusions. These data suggest that in the short term 5 Hz rTMS benefits functional fine motor task performance, perhaps by altering cortical excitability across a network of brain regions. Further, these data may provide the foundation for a larger investigation of the effects of noninvasive brain stimulation over the SMA in individuals with PD.

  9. Effect of transcranial magnetic stimulation on four types of pressure-programmable valves.

    Science.gov (United States)

    Lefranc, Michel; Ko, Julie Yeung Lam; Peltier, Johann; Fichten, Anthony; Desenclos, Christine; Macron, Jean-Michel; Toussaint, Patrick; Le Gars, Daniel; Petitjean, Michel

    2010-04-01

    Exposure to powerful magnetic fields may alter the settings of programmable ventriculoperitoneal shunt valves or even cause permanent damage to these devices. Transcranial magnetic stimulation (TMS) and magnetic resonance imaging both generate a high-intensity, focal magnetic field. To the best of our knowledge, there is no literature data on the compatibility of TMS with neurosurgical implants. The aim of the present in vitro study was to investigate the effects of TMS on four types of pressure-programmable valves (the Strata 2 from Medtronic, the Polaris from Sophysa, the ProGAV from Miethke, and a cylindrical valve from Codman-Hakim). We used a Magpro X100 stimulator (Medtronic) for monophasic or biphasic TMS via a circular or a figure-of-eight coil. Each valve setting was tested before and after exposure to TMS. Experiment 1: The effect of the coil-valve distance (10, 5, 2.5, and 1 cm) was assessed. Experiment 2: We mimicked in situ stimulation with a human mannequin by placing the valve in a retroauricular position, the TMS circular coil on the apex, and figure-of-eight coil centered over the primary motor area site. Temperature changes were monitored throughout the experiments. Experience 3: TMS-induced valve movements were assessed by using an in-house accelerometric setup. Our results primarily demonstrated that the Strata 2 and Codman-Hakim valves' settings were perturbed by TMS. There was no heating effect for any of the valves. However, TMS induced movements of the Strata 2, Polaris, and ProGAV valves. Experiment 1: The unsetting frequencies observed for the Strata 2 and the Codman-Hakim valve showed an influence of the distance, the coil model, and the magnetic field characteristics, whereas the Polaris and ProGAV's settings remained unchanged. Experiment 2: Unsetting occurred for Strata 2 valve with the circular coil only, whereas the Polaris, ProGAV, and Codman-Hakim valves' settings remained stable. Experiment 3: The Strata 2, Polaris, and Pro

  10. Extracting visual evoked potentials from EEG data recorded during fMRI-guided transcranial magnetic stimulation.

    Science.gov (United States)

    Sadeh, Boaz; Yovel, Galit

    2014-05-12

    Transcranial Magnetic Stimulation (TMS) is an effective method for establishing a causal link between a cortical area and cognitive/neurophysiological effects. Specifically, by creating a transient interference with the normal activity of a target region and measuring changes in an electrophysiological signal, we can establish a causal link between the stimulated brain area or network and the electrophysiological signal that we record. If target brain areas are functionally defined with prior fMRI scan, TMS could be used to link the fMRI activations with evoked potentials recorded. However, conducting such experiments presents significant technical challenges given the high amplitude artifacts introduced into the EEG signal by the magnetic pulse, and the difficulty to successfully target areas that were functionally defined by fMRI. Here we describe a methodology for combining these three common tools: TMS, EEG, and fMRI. We explain how to guide the stimulator's coil to the desired target area using anatomical or functional MRI data, how to record EEG during concurrent TMS, how to design an ERP study suitable for EEG-TMS combination and how to extract reliable ERP from the recorded data. We will provide representative results from a previously published study, in which fMRI-guided TMS was used concurrently with EEG to show that the face-selective N1 and the body-selective N1 component of the ERP are associated with distinct neural networks in extrastriate cortex. This method allows us to combine the high spatial resolution of fMRI with the high temporal resolution of TMS and EEG and therefore obtain a comprehensive understanding of the neural basis of various cognitive processes.

  11. Transcranial magnetic therapy is an effective strategy for remediating neuroendocrine pathology

    Directory of Open Access Journals (Sweden)

    Nina V. Bolotova

    2017-03-01

    Full Text Available Aspects of reactivation and remediation of impaired functions of the brain and of the inner organs regulatory systems are crucial to medical science. The study presents the technique of transcranial magnetic therapy (TMT with extremely low frequency alternating magnetic field employed for balanced activation of central nervous system function. This study was aimed to assess the effectiveness of TMT in diseases caused by hypothalamic–pituitary dysfunction. Material and Methods ― 90 children aged 10-16 years with different diseases but with similar pathogenic patterns were enrolled in the study. Group 1 included 30 adolescent girls with menstrual irregularities. Group 2 included 30 children with nocturnal enuresis. Group 3 included 30 teenage boys with constitutional delay of growth and puberty. Medical histories were studied, clinical and laboratory evaluation was carried out. TMT stimulation was performed using the device “AMO-ATOS” (TRIMA LLC, Saratov, Russia. Results ― Children in all the groups had high incidence of antenatal and perinatal pathologies recorded in their medical histories. Analysis of electroencephalograms (EEG showed the prevalence of disorganized and flat EEG patterns – 70% in all the children. Sympathicotonia being the symptom of autonomic nervous system dysfunction, prevailed in 60-80% of the children. The children in the three groups had hormonal imbalance. The treatment with TMT resulted in considerable improvement in hormonal balance and laboratory findings. Conclusion ― ТМТ stimulation is effective in remediation of impaired functions of the brain and treatment of the diseases caused by hypothalamic–pituitary dysfunction.

  12. Static field influences on transcranial magnetic stimulation: considerations for TMS in the scanner environment.

    Science.gov (United States)

    Yau, Jeffrey M; Jalinous, Reza; Cantarero, Gabriela L; Desmond, John E

    2014-01-01

    Transcranial magnetic stimulation (TMS) can be combined with functional magnetic resonance imaging (fMRI) to simultaneously manipulate and monitor human cortical responses. Although tremendous efforts have been directed at characterizing the impact of TMS on image acquisition, the influence of the scanner's static field on the TMS coil has received limited attention. The aim of this study was to characterize the influence of the scanner's static field on TMS. We hypothesized that spatial variations in the static field could account for TMS field variations in the scanner environment. Using an MRI-compatible TMS coil, we estimated TMS field strengths based on TMS-induced voltage changes measured in a search coil. We compared peak field strengths obtained with the TMS coil positioned at different locations (B0 field vs fringe field) and orientations in the static field. We also measured the scanner's static field to derive a field map to account for TMS field variations. TMS field strength scaled depending on coil location and orientation with respect to the static field. Larger TMS field variations were observed in fringe field regions near the gantry as compared to regions inside the bore or further removed from the bore. The scanner's static field also exhibited the greatest spatial variations in fringe field regions near the gantry. The scanner's static field influences TMS fields and spatial variations in the static field correlate with TMS field variations. Coil orientation changes in the B0 field did not result in substantial TMS field variations. TMS field variations can be minimized by delivering TMS in the bore or outside of the 0-70 cm region from the bore entrance. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Acute rCBF changes in depressed patients receiving repetitive transcranial magnetic stimulation (rTMS)

    International Nuclear Information System (INIS)

    Haindl, W.; Loo, C.; Mitchell, P.; Sachdev, P.; Zheng, X.; Som, S.; Walker, B.

    1999-01-01

    Full text: Electroconvulsant therapy (ECT) is very effective in treatment resistant severe depression with response rates of 70-90%. However, ECT has major limitations including the need for anaesthesia, memory difficulties and public apprehension about its use. Transcranial magnetic stimulation (rTMS) has been used as a diagnostic technique in neurology with recent reports of potential benefit in depressed patients. In this study, 5 patients (3 females, 2 males aged 36-66 years, mean 48.6 years) with major depression underwent SPET brain scanning using a Picker 3000 triple-headed camera. Each patient had a baseline rCBF scan with 500 MBq of 99 Tc m HMPAO injected intravenously during sham rTMS. On the following day, each patient received another 500 MBq of 99 Tc m HMPAo during rTMS to the left dorsolateral prefrontal cortex using a Magstim Super Rapid magnetic stimulator with a 70-mm figure eight coil. The stimulator parameters were 15 Hz, 90% of resting motor threshold, 1 s on 3 s off for 30 trains prior to injection and 15-30 trains following injection. Each patient continued to receive their usual medication during this period. The reconstructed SPET data sets were normalized to the global mean, registered to the Talairach template and analysed using statistical parametric mapping (SPM). Compared with the baseline group, the rTMS group showed a significant perfusion increase in the pre-frontal cortices, especially on the left, and also in the anterior left temporal lobe (P < 0.05). Frontal lobe perfusion reduction is a common finding in depression. This study demonstrates the ability of rTMS to acutely increase frontal lobe perfusion, and therefore a possible mechanism for its therapeutic use as an adjunct to pharmacological therapy or as an alternative to ECT in depression

  14. Solving the orientation specific constraints in transcranial magnetic stimulation by rotating fields.

    Directory of Open Access Journals (Sweden)

    Assaf Rotem

    Full Text Available Transcranial Magnetic Stimulation (TMS is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback and will enable stimulation in brain regions where a preferred axonal orientation does not exist.

  15. Transcranial magnetic stimulation for treatment of major depression during pregnancy: a review

    Directory of Open Access Journals (Sweden)

    Renata de Melo Felipe

    Full Text Available Abstract Introduction: Pregnancy is characterized by a high prevalence of mental disorders. Depression is the most common of these disorders and it is a risk factor for negative maternal and child development outcomes. Psychotherapy and pharmacotherapy are conventional and well-established therapeutic options, but some clients fail to respond and the safety of using some pharmacological agents during pregnancy is unclear. Some neuromodulation techniques, such as repetitive transcranial magnetic stimulation (rTMS, have been studied in depressed pregnant women. Objective: To evaluate the safety and efficacy of rTMS for major depression in pregnant women. Methods: The LILACS and PubMed databases were reviewed using the search terms depression, pregnancy and magnetic stimulation. Texts including primary data, published in Portuguese, Spanish, or English, between 1995 and 2014, that evaluated depressed pregnant women and used rTMS as the intervention were selected. Papers lacking sufficient data were excluded. Twenty-two texts were initially identified; after applying the inclusion criteria, 12 were selected and analyzed. Results: The studies reviewed reported satisfactory responses to rTMS in acute depressive episodes, as measured using depressive symptom scales. Remission of symptoms was achieved in many cases. The procedure was well tolerated and there were no reports of damage/complications to unborn children. Conclusion: The data available at this time support the efficacy and tolerability of rTMS for depression in pregnant women. Controlled studies should corroborate this conclusion. This review only included studies in three languages and the resulting sample size was not large enough to conduct a meta-analysis.

  16. Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus

    2009-01-01

    at 20 min) of either anodal so-tDCS or constant tDCS (c-tDCS) to the primary motor hand area during quiet wakefulness. Simultaneously and time-locked to different phase angles of the slow oscillation, motor-evoked potentials (MEPs) as an index of corticospinal excitability were obtained...... individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks...... in the contralateral hand muscles 10, 20, and 30 s after the onset of tDCS. MEPs were also measured off-line before, between, and after both stimulation blocks to detect any lasting excitability shifts. Both tDCS modes increased MEP amplitudes during stimulation with an attenuation of the facilitatory effect toward...

  17. The number of stimuli required to reliably assess corticomotor excitability and primary motor cortical representations using transcranial magnetic stimulation (TMS): a systematic review and meta-analysis.

    Science.gov (United States)

    Cavaleri, Rocco; Schabrun, Siobhan M; Chipchase, Lucy S

    2017-03-06

    Transcranial magnetic stimulation (TMS) is a non-invasive means by which to assess the structure and function of the central nervous system. Current practices involve the administration of multiple stimuli over target areas of a participant's scalp. Decreasing the number of stimuli delivered during TMS assessments would improve time efficiency and decrease participant demand. However, doing so may also compromise the within- or between-session reliability of the technique. The aim of this review was therefore to determine the minimum number of TMS stimuli required to reliably measure (i) corticomotor excitability of a target muscle at a single cranial site and (ii) topography of the primary motor cortical representation of a target muscle across multiple cranial sites. Database searches were performed to identify diagnostic reliability studies published before May 2015. Two independent reviewers extracted data from studies employing single-pulse TMS to measure (i) the corticomotor excitability at a single cranial site or (ii) the topographic cortical organisation of a target muscle across a number of cranial sites. Outcome measures included motor evoked potential amplitude, map volume, number of active map sites and location of the map centre of gravity. Only studies comparing the reliability of varying numbers of stimuli delivered to a single cranial site were identified. Five was the lowest number of stimuli that could be delivered to produce excellent within-session motor evoked potential (MEP) amplitude reliability (intraclass correlation coefficient (ICC) = 0.92, 95% CI 0.87 to 0.95). Ten stimuli were required to achieve consistent between-session MEP amplitudes among healthy participants (ICC = 0.89, 95% CI 0.76 to 0.95). However, between-session reliability was influenced by participant characteristics, intersession intervals and target musculature. Further exploration of the reliability of multi-site TMS mapping is required. Five stimuli produce

  18. Assessment of abdominal muscle function in individuals with motor-complete spinal cord injury above T6 in response to transcranial magnetic stimulation.

    Science.gov (United States)

    Bjerkefors, Anna; Squair, Jordan W; Chua, Romeo; Lam, Tania; Chen, Zhen; Carpenter, Mark G

    2015-02-01

    To use transcranial magnetic stimulation and electromyography to assess the potential for preserved function in the abdominal muscles in individuals classified with motor-complete spinal cord injury above T6. Five individuals with spinal cord injury (C5-T3) and 5 able-bodied individuals. Transcranial magnetic stimulation was delivered over the abdominal region of primary motor cortex during resting and sub-maximal (or attempted) contractions. Surface electromyography was used to record motor-evoked potentials as well as maximal voluntary (or attempted) contractions in the abdominal muscles and the diaphragm. Responses to transcranial magnetic stimulation in the abdominal muscles occurred in all spinal cord injury subjects. Latencies of muscle response onsets were similar in both groups; however, peak-to-peak amplitudes were smaller in the spinal cord injury group. During maximal voluntary (or attempted) contractions all spinal cord injury subjects were able to elicit electromyography activity above resting levels in more than one abdominal muscle across tasks. Individuals with motor-complete spinal cord injury above T6 were able to activate abdominal muscles in response to transcranial magnetic stimulation and during maximal voluntary (or attempted) contractions. The activation was induced directly through corticospinal pathways, and not indirectly by stretch reflex activations of the diaphragm. Transcranial magnetic stimulation and electromyography measurements provide a useful method to assess motor preservation of abdominal muscles in persons with spinal cord injury.

  19. Safety of repetitive transcranial magnetic stimulation in patients with epilepsy: A systematic review.

    Science.gov (United States)

    Pereira, Luisa Santos; Müller, Vanessa Teixeira; da Mota Gomes, Marleide; Rotenberg, Alexander; Fregni, Felipe

    2016-04-01

    Approximately one-third of patients with epilepsy remain with pharmacologically intractable seizures. An emerging therapeutic modality for seizure suppression is repetitive transcranial magnetic stimulation (rTMS). Despite being considered a safe technique, rTMS carries the risk of inducing seizures, among other milder adverse events, and thus, its safety in the population with epilepsy should be continuously assessed. We performed an updated systematic review on the safety and tolerability of rTMS in patients with epilepsy, similar to a previous report published in 2007 (Bae EH, Schrader LM, Machii K, Alonso-Alonso M, Riviello JJ, Pascual-Leone A, Rotenberg A. Safety and tolerability of repetitive transcranial magnetic stimulation in patients with epilepsy: a review of the literature. Epilepsy Behav. 2007; 10 (4): 521-8), and estimated the risk of seizures and other adverse events during or shortly after rTMS application. We searched the literature for reports of rTMS being applied on patients with epilepsy, with no time or language restrictions, and obtained studies published from January 1990 to August 2015. A total of 46 publications were identified, of which 16 were new studies published after the previous safety review of 2007. We noted the total number of subjects with epilepsy undergoing rTMS, medication usage, incidence of adverse events, and rTMS protocol parameters: frequency, intensity, total number of stimuli, train duration, intertrain intervals, coil type, and stimulation site. Our main data analysis included separate calculations for crude per subject risk of seizure and other adverse events, as well as risk per 1000 stimuli. We also performed an exploratory, secondary analysis on the risk of seizure and other adverse events according to the type of coil used (figure-of-8 or circular), stimulation frequency (≤ 1 Hz or > 1 Hz), pulse intensity in terms of motor threshold (<100% or ≥ 100%), and number of stimuli per session (< 500 or ≥ 500

  20. A novel low-cost approach for navigated transcranial magnetic stimulation.

    Science.gov (United States)

    Rodseth, Jakob; Washabaugh, Edward P; Krishnan, Chandramouli

    2017-01-01

    Transcranial magnetic stimulation (TMS) is commonly used for assessing or modulating brain excitability. However, the credibility of TMS outcomes depends on accurate and reliable coil placement during stimulation. Navigated TMS systems can address this issue, but these systems are expensive for routine use in clinical and research environments. The purpose of this study was to provide a high-quality open source framework for navigated TMS and test its reliability and accuracy using standard TMS procedures. A navigated TMS system was created using a low-cost 3D camera system (OptiTrack Trio), which communicates with our free and open source software environment programmed using the Unity 3D gaming engine. The environment is user friendly and has functions to allow for a variety of stimulation procedures (e.g., head and coil co-registration, multiple hotspot/grid tracking, intuitive matching, and data logging). The system was then validated using a static mockup of a TMS session. The clinical utility was also evaluated by assessing the repeatability and operator accuracy when collecting motor evoked potential (MEP) data from human subjects. The system was highly reliable and improved coil placement accuracy (position error = 1.2 mm and orientation error = 0.3°) as well as the quality and consistency (ICC >0.95) of MEPs recorded during TMS. These results indicate that the proposed system is a viable tool for reliable coil placement during TMS procedures, and can improve accuracy in locating the coil over a desired hotspot both within and between sessions.

  1. Assessing and inducing neuroplasticity with transcranial magnetic stimulation and robotics for motor function.

    Science.gov (United States)

    O'Malley, Marcia K; Ro, Tony; Levin, Harvey S

    2006-12-01

    To describe 2 new ways of assessing and inducing neuroplasticity in the human brain--transcranial magnetic stimulation (TMS) and robotics--and to investigate and promote the recovery of motor function after brain damage. We identified recent articles and books directly bearing on TMS and robotics. Articles using these tools for purposes other than rehabilitation were excluded. From these studies, we emphasize the methodologic and technical details of these tools as applicable for assessing and inducing plasticity. Because both tools have only recently been used for rehabilitation, the majority of the articles selected for this review have been published only within the last 10 years. We used the PubMed and Compendex databases to find relevant peer-reviewed studies for this review. The studies were required to be relevant to rehabilitation and to use TMS or robotics methodologies. Guidelines were applied via independent extraction by multiple observers. Despite the limited amount of research using these procedures for assessing and inducing neuroplasticity, there is growing evidence that both TMS and robotics can be very effective, inexpensive, and convenient ways for assessing and inducing rehabilitation. Although TMS has primarily been used as an assessment tool for motor function, an increasing number of studies are using TMS as a tool to directly induce plasticity and improve motor function. Similarly, robotic devices have been used for rehabilitation because of their suitability for delivery of highly repeatable training. New directions in robotics-assisted rehabilitation are taking advantage of novel measurements that can be acquired via the devices, enabling unique methods of assessment of motor recovery. As refinements in technology and advances in our knowledge continue, TMS and robotics should play an increasing role in assessing and promoting the recovery of function. Ongoing and future studies combining TMS and robotics within the same populations may

  2. Electric field depth-focality tradeoff in transcranial magnetic stimulation: simulation comparison of 50 coil designs.

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    Deng, Zhi-De; Lisanby, Sarah H; Peterchev, Angel V

    2013-01-01

    Various transcranial magnetic stimulation (TMS) coil designs are available or have been proposed. However, key coil characteristics such as electric field focality and attenuation in depth have not been adequately compared. Knowledge of the coil focality and depth characteristics can help TMS researchers and clinicians with coil selection and interpretation of TMS studies. To quantify the electric field focality and depth of penetration of various TMS coils. The electric field distributions induced by 50 TMS coils were simulated in a spherical human head model using the finite element method. For each coil design, we quantified the electric field penetration by the half-value depth, d(1/2), and focality by the tangential spread, S(1/2), defined as the half-value volume (V(1/2)) divided by the half-value depth, S(1/2) = V(1/2)/d(1/2). The 50 TMS coils exhibit a wide range of electric field focality and depth, but all followed a depth-focality tradeoff: coils with larger half-value depth cannot be as focal as more superficial coils. The ranges of achievable d(1/2) are similar between coils producing circular and figure-8 electric field patterns, ranging 1.0-3.5 cm and 0.9-3.4 cm, respectively. However, figure-8 field coils are more focal, having S(1/2) as low as 5 cm(2) compared to 34 cm(2) for circular field coils. For any coil design, the ability to directly stimulate deeper brain structures is obtained at the expense of inducing wider electrical field spread. Novel coil designs should be benchmarked against comparison coils with consistent metrics such as d(1/2) and S(1/2). Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Transcranial Magnetic Stimulation in the Treatment of Chronic Widespread Pain: A Randomized, Controlled Study

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    Avery, David H.; Zarkowski, Paul; Krashin, Daniel; Rho, Wang-ku; Wajdik, Chandra; Joesch, Jutta M.; Haynor, David R.; Buchwald, Dedra; Roy-Byrne, Peter

    2014-01-01

    Objective Our objective was to assess transcranial magnetic stimulation (TMS) in the treatment of chronic widespread pain (CWP). Methods Nineteen participants were randomized to two groups: one receiving active TMS (N=7) and another receiving sham stimulation (N=11) applied to the left dorsolateral prefrontal cortex. During sham stimulation, subjects heard a sound similar to the sound heard by those receiving the active treatment and received an active electrical stimulus to the scalp. The stimulation protocol consisted of 15 sessions completed within a 4-week period. Blind assessments were done at baseline and after each 5 sessions followed by blind assessments at 1 week, 1 month and 3 months after the last TMS sessions. The primary outcome variable was a pain measure, the Gracely Box Intensity Scale (BIRS). Results The percentage of subjects who guessed that they were receiving TMS was similar in the two groups. Both the TMS group and the sham group showed a statistically significant reduction in the BIRS scores from baseline during the acute phase of treatment and the follow-up phase. However, the TMS and sham groups did not differ in the change in the BIRS scores. Discussion Although some previous clinical studies and basic science studies of TMS in treating pain are promising, this study found no difference in the analgesic effect of TMS and sham stimulation. Future studies should utilize a sham condition that attempts to simulate the sound and sensation of the TMS stimulation. Stimulus location and other stimulus parameters should be explored in future studies. PMID:24755729

  4. MagPy: A Python toolbox for controlling Magstim transcranial magnetic stimulators.

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    McNair, Nicolas A

    2017-01-30

    To date, transcranial magnetic stimulation (TMS) studies manipulating stimulation parameters have largely used blocked paradigms. However, altering these parameters on a trial-by-trial basis in Magstim stimulators is complicated by the need to send regular (1Hz) commands to the stimulator. Additionally, effecting such control interferes with the ability to send TMS pulses or simultaneously present stimuli with high-temporal precision. This manuscript presents the MagPy toolbox, a Python software package that provides full control over Magstim stimulators via the serial port. It is able to maintain this control with no impact on concurrent processing, such as stimulus delivery. In addition, a specially-designed "QuickFire" serial cable is specified that allows MagPy to trigger TMS pulses with very low-latency. In a series of experimental simulations, MagPy was able to maintain uninterrupted remote control over the connected Magstim stimulator across all testing sessions. In addition, having MagPy enabled had no effect on stimulus timing - all stimuli were presented for precisely the duration specified. Finally, using the QuickFire cable, MagPy was able to elicit TMS pulses with sub-millisecond latencies. The MagPy toolbox allows for experiments that require manipulating stimulation parameters from trial to trial. Furthermore, it can achieve this in contexts that require tight control over timing, such as those seeking to combine TMS with fMRI or EEG. Together, the MagPy toolbox and QuickFire serial cable provide an effective means for controlling Magstim stimulators during experiments while ensuring high-precision timing. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Uncertainty quantification in transcranial magnetic stimulation via high-dimensional model representation.

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    Gomez, Luis J; Yücel, Abdulkadir C; Hernandez-Garcia, Luis; Taylor, Stephan F; Michielssen, Eric

    2015-01-01

    A computational framework for uncertainty quantification in transcranial magnetic stimulation (TMS) is presented. The framework leverages high-dimensional model representations (HDMRs), which approximate observables (i.e., quantities of interest such as electric (E) fields induced inside targeted cortical regions) via series of iteratively constructed component functions involving only the most significant random variables (i.e., parameters that characterize the uncertainty in a TMS setup such as the position and orientation of TMS coils, as well as the size, shape, and conductivity of the head tissue). The component functions of HDMR expansions are approximated via a multielement probabilistic collocation (ME-PC) method. While approximating each component function, a quasi-static finite-difference simulator is used to compute observables at integration/collocation points dictated by the ME-PC method. The proposed framework requires far fewer simulations than traditional Monte Carlo methods for providing highly accurate statistical information (e.g., the mean and standard deviation) about the observables. The efficiency and accuracy of the proposed framework are demonstrated via its application to the statistical characterization of E-fields generated by TMS inside cortical regions of an MRI-derived realistic head model. Numerical results show that while uncertainties in tissue conductivities have negligible effects on TMS operation, variations in coil position/orientation and brain size significantly affect the induced E-fields. Our numerical results have several implications for the use of TMS during depression therapy: 1) uncertainty in the coil position and orientation may reduce the response rates of patients; 2) practitioners should favor targets on the crest of a gyrus to obtain maximal stimulation; and 3) an increasing scalp-to-cortex distance reduces the magnitude of E-fields on the surface and inside the cortex.

  6. Excitability of the motor system: A transcranial magnetic stimulation study on singing and speaking.

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    Royal, Isabelle; Lidji, Pascale; Théoret, Hugo; Russo, Frank A; Peretz, Isabelle

    2015-08-01

    The perception of movements is associated with increased activity in the human motor cortex, which in turn may underlie our ability to understand actions, as it may be implicated in the recognition, understanding and imitation of actions. Here, we investigated the involvement and lateralization of the primary motor cortex (M1) in the perception of singing and speech. Transcranial magnetic stimulation (TMS) was applied independently for both hemispheres over the mouth representation of the motor cortex in healthy participants while they watched 4-s audiovisual excerpts of singers producing a 2-note ascending interval (singing condition) or 4-s audiovisual excerpts of a person explaining a proverb (speech condition). Subjects were instructed to determine whether a sung interval/written proverb, matched a written interval/proverb. During both tasks, motor evoked potentials (MEPs) were recorded from the contralateral mouth muscle (orbicularis oris) of the stimulated motor cortex compared to a control task. Moreover, to investigate the time course of motor activation, TMS pulses were randomly delivered at 7 different time points (ranging from 500 to 3500 ms after stimulus onset). Results show that stimulation of the right hemisphere had a similar effect on the MEPs for both the singing and speech perception tasks, whereas stimulation of the left hemisphere significantly differed in the speech perception task compared to the singing perception task. Furthermore, analysis of the MEPs in the singing task revealed that they decreased for small musical intervals, but increased for large musical intervals, regardless of which hemisphere was stimulated. Overall, these results suggest a dissociation between the lateralization of M1 activity for speech perception and for singing perception, and that in the latter case its activity can be modulated by musical parameters such as the size of a musical interval. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Preoperative navigated transcranial magnetic stimulation in patients with motor eloquent lesions with emphasis on metastasis.

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    Hendrix, Philipp; Senger, Sebastian; Griessenauer, Christoph J; Simgen, Andreas; Schwerdtfeger, Karsten; Oertel, Joachim

    2016-10-01

    Navigated transcranial magnetic stimulation (nTMS) is a frequently used, non-invasive method to map the motor cortex. It is of great value in the preoperative workup of patients that suffer from motor eloquent brain lesions. Here, we present a single-center experience using preoperative nTMS in cortical motor eloquent lesions with emphasis on metastasis. All patients that underwent preoperative nTMS between June 2013 and January 2016 were evaluated. A total of 61 patients underwent nTMS before undergoing surgery for a motor eloquent brain lesion. Patients suffered from cerebral metastasis (23), glioblastoma (16), high grade glioma WHO III (4), low grade glioma WHO II (4), lymphoma (2), meningioma (8), cavernous hemangioma (3), or arteriovenous malformation (1). Thirty patients (49.2%) presented with a preoperative motor deficit. One week after surgery, paresis had resolved or improved in 56.7% of the patients. Out of the patients with postoperative paresis, 89.5% experienced an improvement of motor status at follow-up. All metastatic lesions were completely resected compared to 78.9% of non-metastatic lesions (P = 0.02). Only 4.3% of patients with a metastatic lesion, but 26.3% of patients with a non-metastatic lesion experienced deterioration of motor function after surgery (P = 0.04). Preoperative nTMS is suitable for mapping of a variety of motor eloquent brain lesions resulting in favorable neurological outcome. Particularly in metastatic motor eloquent lesion, motor function appears to be preserved after surgery. Clin. Anat. 29:925-931, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Motor Cortex Reorganization and Repetitive Transcranial Magnetic Stimulation for Pain-A Methodological Study.

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    Nurmikko, Turo; MacIver, Kathryn; Bresnahan, Rebecca; Hird, Emily; Nelson, Andrew; Sacco, Paul

    2016-10-01

    Somatotopic reorganization of primary motor cortex (M1) has been described in several neurological conditions associated with chronic pain. We hypothesized that such reorganization impacts on the mechanisms of M1 stimulation induced analgesia and may either compromise the treatment effect of or provide an alternative target site for repetitive transcranial magnetic stimulation (rTMS). The aim of the study was to compare pain relief following rTMS of the standard motor "hotspot" with that of the reorganized area. We used TMS motor mapping in 30 patients to establish the location of the standard motor "hotspot" (site A) and an alternative site located in the reorganized area (site B), both within M1. Where TMS mapping was not possible (N = 8) we determined the location of the two sites using task-related fMRI. We compared the analgesic effect on neuropathic pain of 5 sessions of navigated rTMS applied over (i) site A, (ii) site B, and (iii) occipital fissure (SHAM stimulation site). Total Pain Relief (TOTPAR) was determined as the difference in average weekly pain scores between baseline and following each rTMS cycle, over three weeks. Data from 27 patients was analyzed. rTMS of sites A and B resulted in greater TOTPAR than that of SHAM. No difference was seen between sites A and B. Responders (≥15% pain relief) were seen in both groups, with partial overlap only. Addition of stimulation over site B improved the responder rate by 58% compared with site A. In an open-label extension study of five sessions of rTMS aimed at the optimized target site, 8/11 responders and 1/12 nonresponders reported pain relief. Cortical reorganization may provide a more effective stimulation target for rTMS in some individuals with neuropathic pain. © 2016 International Neuromodulation Society.

  9. Risk stratification in motor area-related glioma surgery based on navigated transcranial magnetic stimulation data.

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    Rosenstock, Tizian; Grittner, Ulrike; Acker, Güliz; Schwarzer, Vera; Kulchytska, Nataliia; Vajkoczy, Peter; Picht, Thomas

    2017-04-01

    OBJECTIVE Navigated transcranial magnetic stimulation (nTMS) is a noninvasive method for preoperatively localizing functional areas in patients with tumors in presumed motor eloquent areas. The aim of this study was to establish an nTMS-based risk stratification model by examining whether the results of nTMS mapping and its neurophysiological data predict postoperative motor outcome in glioma surgery. METHODS Included in this study were prospectively collected data for 113 patients undergoing bihemispheric nTMS examination prior to surgery for gliomas in presumed motor eloquent locations. Multiple ordinal logistic regression analysis was performed to test for any association between preoperative nTMS-related variables and postoperative motor outcome. RESULTS A new motor deficit or deterioration due to a preexisting deficit was observed in 20% of cases after 7 days and in 22% after 3 months. In terms of tumor location, no new permanent deficit was observed when the distance between tumor and corticospinal tract was greater than 8 mm and the precentral gyrus was not infiltrated (p = 0.014). New postoperative deficits on Day 7 were associated with a pathological excitability of the motor cortices (interhemispheric resting motor threshold [RMT] ratio 110%, p = 0.031). Interestingly, motor function never improved when the RMT was significantly higher in the tumorous hemisphere than in the healthy hemisphere (RMT ratio > 110%). CONCLUSIONS The proposed risk stratification model, based on objective functional-anatomical and neurophysiological measures, enables one to counsel patients about the risk of functional deterioration or the potential for recovery.

  10. The Use and Abuse of Transcranial Magnetic Stimulation to Modulate Corticospinal Excitability in Humans.

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    Martin E Héroux

    Full Text Available The magnitude and direction of reported physiological effects induced using transcranial magnetic stimulation (TMS to modulate human motor cortical excitability have proven difficult to replicate routinely. We conducted an online survey on the prevalence and possible causes of these reproducibility issues. A total of 153 researchers were identified via their publications and invited to complete an anonymous internet-based survey that asked about their experience trying to reproduce published findings for various TMS protocols. The prevalence of questionable research practices known to contribute to low reproducibility was also determined. We received 47 completed surveys from researchers with an average of 16.4 published papers (95% CI 10.8-22.0 that used TMS to modulate motor cortical excitability. Respondents also had a mean of 4.0 (2.5-5.7 relevant completed studies that would never be published. Across a range of TMS protocols, 45-60% of respondents found similar results to those in the original publications; the other respondents were able to reproduce the original effects only sometimes or not at all. Only 20% of respondents used formal power calculations to determine study sample sizes. Others relied on previously published studies (25%, personal experience (24% or flexible post-hoc criteria (41%. Approximately 44% of respondents knew researchers who engaged in questionable research practices (range 30–81%, yet only 18% admitted to engaging in them (range 6–38% [corrected]. These practices included screening subjects to find those that respond in a desired way to a TMS protocol, selectively reporting results and rejecting data based on a gut feeling. In a sample of 56 published papers that were inspected, not a single questionable research practice was reported. Our survey revealed that approximately 50% of researchers are unable to reproduce published TMS effects. Researchers need to start increasing study sample size and eliminating

  11. Cortical plasticity induced by transcranial magnetic stimulation during wakefulness affects electroencephalogram activity during sleep.

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    Luigi De Gennaro

    Full Text Available BACKGROUND: Sleep electroencephalogram (EEG brain oscillations in the low-frequency range show local signs of homeostatic regulation after learning. Such increases and decreases of slow wave activity are limited to the cortical regions involved in specific task performance during wakefulness. Here, we test the hypothesis that reorganization of motor cortex produced by long-term potentiation (LTP affects EEG activity of this brain area during subsequent sleep. METHODOLOGY/PRINCIPAL FINDINGS: By pairing median nerve stimulation with transcranial magnetic stimulation over the contralateral motor cortex, one can potentiate the motor output, which is presumed to reflect plasticity of the neural circuitry. This paired associative stimulation increases M1 cortical excitability at interstimulus intervals of 25 ms. We compared the scalp distribution of sleep EEG power following paired associative stimulation at 25 ms to that following a control paradigm with 50 ms intervals. It is shown that the experimental manipulation by paired associative stimulation at 25 ms induces a 48% increase in amplitude of motor evoked potentials. This LTP-like potentiation, induced during waking, affects delta and theta EEG power in both REM and non-REM sleep, measured during the following night. Slow-wave activity increases in some frontal and prefrontal derivations and decreases at sites neighboring and contralateral to the stimulated motor cortex. The magnitude of increased amplitudes of motor evoked potentials by the paired associative stimulation at 25 ms predicts enhancements of slow-wave activity in prefrontal regions. CONCLUSIONS/SIGNIFICANCE: An LTP-like paradigm, presumably inducing increased synaptic strength, leads to changes in local sleep regulation, as indexed by EEG slow-wave activity. Enhancement and depression of slow-wave activity are interpreted in terms of a simultaneous activation of both excitatory and inhibitory circuits consequent to the paired

  12. Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.

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    Paul A Muller

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP, presumably reflecting long-term depression (LTD -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1 reproduce cortico-spinal depression by LF rTMS in rats, (2 establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3 test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR, by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.

  13. Effects of repetitive transcranial magnetic stimulation on the somatosensory cortex during prism adaptation.

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    Yoon, Hee-Chul; Lee, Kyung-Hyun; Huh, Dong-Chan; Lee, Ji-Hang; Lee, Dong-Hyun

    2014-04-01

    Although the behavioral characteristics and the neural correlates of prism adaptation processes have been studied extensively, the underlying mechanism is yet to be investigated. Recently, somatosensory suppression was heralded as a mechanism for the sensory re-alignment process accompanying the adaptation. Somatosensory suppression should facilitate the re-alignment process in the proprioceptive system. The shift in the proprioceptive system takes place mostly during a concurrent visual feedback (CVF) condition; during a terminal visual feedback (TVF) condition, the visual system experiences significant adaptation (visual shift), so somatosensory suppression should have minimal functional consequences under TVF. To test this hypothesis, a repetitive transcranial magnetic stimulation (rTMS) was applied to the primary somatosensory cortex as an artificial somatosensory suppression right after the reaching initiation in CVF and TVF conditions, and changes in adaptation were observed. Because somatosensory suppression is already in effect during CVF, rTMS would cause no significant changes. During TVF with rTMS, however, significantly different patterns of adaptation could be expected when compared to a sham rTMS condition. Young adults (N = 12) participated in 4 sessions (CVF/ TVF, real/sham rTMS); visual proprioceptive, and total shifts were measured. Movement time and curvature of the reaching movement were measured during the adaptation phase. Results showed that while the total shift was unchanged, the proprioceptive shift increased and the visual shift decreased in the TVF condition when rTMS was delivered. However, the total, proprioceptive, and visual shifts were not influenced by rTMS in the CVF condition. Suppression of proprioception induced by the rTMS could be one of the requisites for successful proprioceptive shift during prism adaptation.

  14. Repetitive transcranial magnetic stimulation for treatment of major depressive disorder with comorbid generalized anxiety disorder.

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    White, Daniela; Tavakoli, Sason

    2015-08-01

    Repetitive transcranial magnetic stimulation (rTMS) has shown promising results in treating individuals with behavioral disorders such as major depressive disorder (MDD), posttraumatic stress disorder, obsessive-compulsive disorder, and social anxiety disorder. A number of applications of rTMS to different regions of the left and right prefrontal cortex have been used to treat these disorders, but no study of treatment for MDD with generalized anxiety disorder (GAD) has been conducted with application of rTMS to both the left and right prefrontal cortex. We hypothesized that applying low-frequency rTMS to the right dorsolateral prefrontal cortex (DLPFC) before applying it to the left DLPFC for the treatment of depression would be anxiolytic in patients with MDD with GAD. Thirteen adult patients with comorbid MDD and GAD received treatment with rTMS in an outpatient setting. The number of treatments ranged from 24 to 36 over 5 to 6 weeks. Response was defined as a ≥ 50% reduction in symptoms from baseline, and remission was defined as a score of anxiety symptoms on the 7-item Generalized Anxiety Disorder (GAD-7) scale and depressive symptoms on the 21-item Hamilton Rating Scale for Depression (HAM-D-21). At the end of the treatment period, for the GAD-7 scale, 11 out of 13 (84.6%) patients' anxiety symptoms were in remission, achieving a score of depressive symptoms. In this small pilot study of 13 patients with comorbid MDD and GAD, significant improvement in anxiety symptoms along with depressive symptoms was achieved in a majority of patients after bilateral rTMS application.

  15. [Possibilities of transcranial magnetic therapy and color and rhythm therapy in rehabilitation of ischemic stroke].

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    Sholomov, I I; Cherevashchenko, L A; Suprunov, O V; Raĭgorondskiĭ, Iu M

    2009-01-01

    One hundred and sixteen post-stroke patients were studied in the early rehabilitation period. All patients were divided into 4 groups: 3 main and 1 control groups. Three main groups (87 patients) received transcranial magnetic therapy (TMT) and/or color and rhythm therapy (CRT) along with traditional treatment and the control group (29 patients) received only basic therapy. TMT was conducted using bitemporal technique, running regime with modulation frequency 1-10 Hz. In CRT, the alternating stimulation of the right and left eye with green and/or blue color with a period of 2-4 s and duration of luminescence 1s was applied. Each of 3 main groups received 2 treatment sessions with an interval of 1,5 month (1st - TMT, 2nd - CRT, 3rd - TMT + CRT). After the treatment, the marked positive changes were seen in all main groups, in particular in group 3. The improvement of neurologic symptoms on the B. Lindmark scale was higher by 9,5% in group 3 compared to the control one, on the Barthel index - by 8,8%, on MMSE and A. Luria and Schulte test - by 5,4 and 14,3%, respectively. Rheographic and encephalographic study revealed the significant improvement of hemodynamics and alpha-rhythm differentiation, decrease of patients with dysrhythmia by 14,6% in group 3 as compared to the control group. The best results were seen in the combination of TMT and CRT, TMT exerted a higher effect on the hemodynamics and CRT - on the psychoemotional state. Both therapies were well tolerated and had no side-effects.

  16. Safety of transcranial magnetic stimulation: review of international guidelines and new findings

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    N. A. Suponeva

    2017-01-01

    Full Text Available Transcranial magnetic stimulation (TMS is a rapidly developing method of neuromodulation. The use of TMS has increased significantly in both research and clinical practice. This allows not only to better understand this method, but also assess possible risks and consequences for both healthy individuals and patients. In 1998 and 2009 safety, ethical considerations, and application guidelines for the use of TMS in clinical practice and research were published. These recommendations are now the basis for safe application of the method in clinical practice and research. Safety of brain stimulation includes several aspects: the prevention and treatment of adverse effects, the strategy of patient and stimulation protocols selection, as well as safety and monitoring procedures. The most common adverse effects of TMS include headache and neck pain, syncope, transient hearing impairment. The risk of epileptic seizureis extremely low and can be minimized by careful selection of patients and the use of safe stimulation protocols. Careful selection of patients is important, taking into account a large number of factors that influence the risk of adverse effects. These factors are considered in the questionnaires to identify limitations and absolute or relative contraindications to TMS. Another important part of TMS safety is the choice of the stimulation protocol and parameters such as intensity, frequency, duration of one train of stimuli, and the interstimulus interval. Currently, the recommended limits of stimulation parameters are covered in the safety guidelines. It is also necessary to follow the procedure, including the monitoring the patient's condition during TMS and the providing qualified assistance in case of adverse effects.

  17. Neurocognitive effects of repetitive transcranial magnetic stimulation in adolescents with major depressive disorder.

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    Wall, Christopher A; Croarkin, Paul E; McClintock, Shawn M; Murphy, Lauren L; Bandel, Lorelei A; Sim, Leslie A; Sampson, Shirlene M

    2013-01-01

    It is estimated that 30-40% of adolescents with major depressive disorder (MDD) do not receive full benefit from current antidepressant therapies. Repetitive transcranial magnetic stimulation (rTMS) is a novel therapy approved by the US Food and Drug Administration to treat adults with MDD. Research suggests rTMS is not associated with adverse neurocognitive effects in adult populations; however, there is no documentation of its neurocognitive effects in adolescents. This is a secondary post hoc analysis of neurocognitive outcome in adolescents who were treated with open-label rTMS in two separate studies. Eighteen patients (mean age, 16.2 ± 1.1 years; 11 females, 7 males) with MDD who failed to adequately respond to at least one antidepressant agent were enrolled in the study. Fourteen patients completed all 30 rTMS treatments (5 days/week, 120% of motor threshold, 10 Hz, 3,000 stimulations per session) applied to the left dorsolateral prefrontal cortex. Depression was rated using the Children's Depression Rating Scale-Revised. Neurocognitive evaluation was performed at baseline and after completion of 30 rTMS treatments with the Children's Auditory Verbal Learning Test (CAVLT) and Delis-Kaplan Executive Function System Trail Making Test. Over the course of 30 rTMS treatments, adolescents showed a substantial decrease in depression severity. Commensurate with improvement in depressive symptoms was a statistically significant improvement in memory and delayed verbal recall. Other learning and memory indices and executive function remained intact. Neither participants nor their family members reported clinically meaningful changes in neurocognitive function. These preliminary findings suggest rTMS does not adversely impact neurocognitive functioning in adolescents and may provide subtle enhancement of verbal memory as measured by the CAVLT. Further controlled investigations with larger sample sizes and rigorous trial designs are warranted to confirm and

  18. 5 Hz repetitive transcranial magnetic stimulation over the ipsilesional sensory cortex enhances motor learning after stroke

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    Sonia M Brodie

    2014-03-01

    Full Text Available Sensory feedback is critical for motor learning, and thus to neurorehabilitation after stroke. Whether enhancing sensory feedback by applying excitatory repetitive transcranial magnetic stimulation (rTMS over the ipsilesional primary sensory cortex (IL-S1 might enhance motor learning in chronic stroke has yet to be investigated. The present study investigated the effects of 5 Hz rTMS over IL-S1 paired with skilled motor practice on motor learning, hemiparetic cutaneous somatosensation, and motor function. Individuals with unilateral chronic stroke were pseudo-randomly divided into either Active or Sham 5 Hz rTMS groups (n=11/group. Following stimulation, both groups practiced a Serial Tracking Task (STT with the hemiparetic arm; this was repeated for 5 days. Performance on the STT was quantified by response time, peak velocity, and cumulative distance tracked at baseline, during the 5 days of practice, and at a no-rTMS retention test. Cutaneous somatosensation was measured using two-point discrimination. Standardized sensorimotor tests were performed to assess whether the effects might generalize to impact hemiparetic arm function. The active 5Hz rTMS + training group demonstrated significantly greater improvements in STT performance [response time (F1,286.04=13.016, p< 0.0005, peak velocity (F1,285.95=4.111, p=0.044, and cumulative distance (F1,285.92=4.076, p=0.044] and cutaneous somatosensation (F1,21.15=8.793, p=0.007 across all sessions compared to the sham rTMS + training group. Measures of upper extremity motor function were not significantly different for either group. Our preliminary results suggest that, when paired with motor practice, 5Hz rTMS over IL-S1 enhances motor learning related change in individuals with chronic stroke, potentially as a consequence of improved cutaneous somatosensation, however no improvement in general upper extremity function was observed.

  19. Benefits of Deep Transcranial Magnetic Stimulation in Alzheimer Disease: Case Series.

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    Avirame, Keren; Stehberg, Jimmy; Todder, Doron

    2016-06-01

    Patients diagnosed with Alzheimer disease (AD) show severe cognitive deficits. Decline in memory, language, and executive function have repeatedly been reported. Although AD affects 60% to 80% of demented elderly patients, there is currently no cure and limited treatment alternatives. The aim of the study was to evaluate the feasibility of stimulating prefrontal cortex (PFC) with deep transcranial magnetic stimulation (dTMS) to ameliorate cognitive deficits in patients suffering from AD. Eleven patients (6 males; mean [SD] age, 76 [7] years) in moderate to severe stages of AD received dTMS over the PFC for 20 sessions. Computerized battery (Mindstreams [MS]) and neuropsychological testing (Addenbrooke Cognitive Examination [ACE]) were used to assess cognitive performance before and after treatment. Compared with baseline, 60% of patients performed better on the MS battery and 77% of patients performed better on the ACE testing at the end of dTMS treatment. None of the patients performed worse on both tests at the end of treatment. The DTMS effects on the group mean in ACE and MS approached significance (P = 0.065 and P = 0.086, respectively). A dTMS-induced improvement in the ACE was significant (P = 0.001) on patients in more progressed stage (n = 6). Change in ACE negatively correlated with score at baseline. In sum, the current report of this novel technique indicates that deep stimulation might lead to preservation and even improvement of cognitive functions, at least during the time of treatment. Further examinations should report of long-term effects of this technique.

  20. Effects of Bilateral Repetitive Transcranial Magnetic Stimulation on Post-Stroke Dysphagia.

    Science.gov (United States)

    Park, Eunhee; Kim, Min Su; Chang, Won Hyuk; Oh, Su Mi; Kim, Yun Kwan; Lee, Ahee; Kim, Yun-Hee

    Optimal protocol of repetitive transcranial magnetic stimulation (rTMS) on post-stroke dysphagia remains uncertain with regard to its clinical efficacy. The aim of the present study is to investigate the effects of high-frequency rTMS at the bilateral motor cortices over the cortical representation of the mylohyoid muscles in the patients with post-stroke dysphagia. This study was a single-blind, randomized controlled study with a blinded observer. Thirty-five stroke patients were randomly divided into three intervention groups: the bilateral stimulation group, the unilateral stimulation group, and the sham stimulation group. For the bilateral stimulation group, 500 pulses of 10 Hz rTMS over the ipsilesional and 500 pulses of 10 Hz rTMS over the contralesional motor cortices over the cortical areas that project to the mylohyoid muscles were administered daily for 2 consecutive weeks. For the unilateral stimulation group, 500 pulses of 10 Hz rTMS over the ipsilesional motor cortex over the cortical representation of the mylohyoid muscle and the same amount of sham rTMS over the contralesional hemisphere were applied. For the sham stimulation group, sham rTMS was applied at the bilateral motor cortices. Clinical swallowing function and videofluoroscopic swallowing studies were assessed before the intervention (T0), immediately after the intervention (T1) and 3 weeks after the intervention (T2) using Clinical Dysphagia Scale (CDS), Dysphagia Outcome and Severity Scale (DOSS), Penetration Aspiration Scale (PAS), and Videofluoroscopic Dysphagia Scale (VDS). There were significant time and intervention interaction effects in the CDS, DOSS, PAS, and VDS scores (p dysphagia therapies. Copyright © 2016. Published by Elsevier Inc.

  1. Repetitive transcranial magnetic stimulation as an adjuvant method in the treatment of depression: Preliminary results

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    Jovičić Milica

    2014-01-01

    Full Text Available Introduction. Repetitive transcranial magnetic stimulation (rTMS is a method of brain stimulation which is increasingly used in both clinical practice and research. Up-to-date studies have pointed out a potential antidepressive effect of rTMS, but definitive superiority over placebo has not yet been confirmed. Objective. The aim of the study was to examine the effect of rTMS as an adjuvant treatment with antidepressants during 18 weeks of evaluation starting from the initial application of the protocol. Methods. Four patients with the diagnosis of moderate/severe major depression were included in the study. The protocol involved 2000 stimuli per day (rTMS frequency of 10 Hz, intensity of 120% motor threshold administered over the left dorsolateral prefrontal cortex (DLPFC for 15 days. Subjective and objective depressive symptoms were measured before the initiation of rTMS and repeatedly evaluated at week 3, 6, 12 and 18 from the beginning of the stimulation. Results. After completion of rTMS protocol two patients demonstrated a reduction of depressive symptoms that was sustained throughout the 15-week follow-up period. One patient showed a tendency of remission during the first 12 weeks of the study, but relapsed in week 18. One patient showed no significant symptom reduction at any point of follow-up. Conclusion. Preliminary findings suggest that rTMS has a good tolerability and can be efficient in accelerating the effect of antidepressants, particularly in individuals with shorter duration of depressive episodes and moderate symptom severity. [Projekat Ministarstva nauke Republike Srbije, br. III41029 i br. ON175090

  2. Repetitive transcranial magnetic stimulation affects behavior by biasing endogenous cortical oscillations

    Directory of Open Access Journals (Sweden)

    Massihullah Hamidi

    2009-06-01

    Full Text Available A governing assumption about repetitive transcranial magnetic stimulation (rTMS has been that it interferes with task-related neuronal activity – in effect, by “injecting noise” into the brain – and thereby disrupts behavior. Recent reports of rTMS-produced behavioral enhancement, however, call this assumption into question. We investigated the neurophysiological effects of rTMS delivered during the delay period of a visual working memory task by simultaneously recording brain activity with electroencephalography (EEG. Subjects performed visual working memory for locations or for shapes, and in half the trials a 10-Hz train of rTMS was delivered to the superior parietal lobule or a control brain area. The wide range of individual differences in the effects of rTMS on task accuracy, from improvement to impairment, was predicted by individual differences in the effect of rTMS on power in the alpha-band of the EEG (~ 10 Hz: a decrease in alpha-band power corresponded to improved performance, whereas an increase in alpha-band power corresponded to the opposite. The EEG effect was localized to cortical sources encompassing the frontal eye fields and the intraparietal sulcus, and was specific to task (location, but not object memory and to rTMS target (superior parietal lobule, not control area. Furthermore, for the same task condition, rTMS-induced changes in cross-frequency phase synchrony between alpha- and gamma-band (> 40 Hz oscillations predicted changes in behavior. These results suggest that alpha-band oscillations play an active role cognitive processes and do not simply reflect absence of processing. Furthermore, this study shows that the complex effects of rTMS on behavior can result from biasing endogenous patterns of network-level oscillations.

  3. Transcranial Magnetic Stimulation of Human Adult Stem Cells in the Mammalian Brain.

    Science.gov (United States)

    Kremer, Karlea L; Smith, Ashleigh E; Sandeman, Lauren; Inglis, Joshua M; Ridding, Michael C; Koblar, Simon A

    2016-01-01

    The burden of stroke on the community is growing, and therefore, so is the need for a therapy to overcome the disability following stroke. Cellular-based therapies are being actively investigated at a pre-clinical and clinical level. Studies have reported the beneficial effects of exogenous stem cell implantation, however, these benefits are also associated with limited survival of implanted stem cells. This exploratory study investigated the use of transcranial magnetic stimulation (TMS) as a complementary therapy to increase stem cell survival following implantation of human dental pulp stem cells (DPSC) in the rodent cortex. Sprague-Dawley rats were anesthetized and injected with 6 × 10(5) DPSC or control media via an intracranial injection, and then received real TMS (TMS0.2 Hz) or sham TMS (TMSsham) every 2nd day beginning on day 3 post DPSC injection for 2 weeks. Brain sections were analyzed for the survival, migration and differentiation characteristics of the implanted cells. In animals treated with DPSC and TMS0.2 Hz there were significantly less implanted DPSC and those that survived remained in the original cerebral hemisphere compared to animals that received TMSsham. The surviving implanted DPSC in TMS0.2 Hz were also found to express the apoptotic marker Caspase-3. We suggest that TMS at this intensity may cause an increase in glutamate levels, which promotes an unfavorable environment for stem cell implantation, proliferation and differentiation. It should be noted that only one paradigm of TMS was tested as this was conducted as a exploratory study, and further TMS paradigms should be investigated in the future.

  4. Performance Characterization of an Actively Cooled Repetitive Transcranial Magnetic Stimulation Coil for the Rat.

    Science.gov (United States)

    Parthoens, Joke; Verhaeghe, Jeroen; Servaes, Stijn; Miranda, Alan; Stroobants, Sigrid; Staelens, Steven

    2016-07-01

    This study characterizes and validates a recently developed dedicated circular rat coil for small animal repetitive Transcranial Magnetic Stimulation (rTMS). The electric (E) field distribution was calculated in a three-dimensional (3D) spherical rat head model and coil cooling performance was characterized. Motor threshold (MT) in rats (n = 12) was determined using two current directions, MT variability (n = 16) and laterality (n = 11) of the stimulation was assessed. Finally, 2-deoxy-2-((18) F)fluoro-D-glucose ([(18) F]-FDG) small animal Positron Emission Tomography (µPET) after sham and 1, 10, and 50 Hz rTMS stimulation (n = 9) with the new Cool-40 Rat Coil (MagVenture, Denmark) was performed. The coil could produce high E-fields of maximum 220 V/m and more than 100 V/m at depths up to 5.3 mm in a ring-shaped distribution. No lateralization of stimulation was observed. Independent of the current direction, reproducible MT measurements were obtained at low percentages (27 ± 6%) of the maximum machine output (MO, MagPro X100 [MagVenture, Denmark]). At this intensity, rTMS with long pulse trains is feasible (1 Hz: continuous stimulation; 5 Hz: 1000 pulses; 10 Hz and 50 Hz: 272 pulses). When compared to sham, rTMS at different frequencies induced decreases in [(18) F]-FDG-uptake bilaterally mainly in dorsal cortical regions (visual, retrosplenial, and somatosensory cortices) and increases mainly in ventral regions (entorhinal cortex and amygdala). The coil is suitable for rTMS in rats and achieves unprecedented high E-fields at high stimulation frequencies and long durations with however a rather unfocal rat brain stimulation. Reproducible MEPs as well as alterations in cerebral glucose metabolism following rTMS were demonstrated. © 2016 International Neuromodulation Society.

  5. Regional cerebral blood flow changes associated with transcranial magnetic stimulation in refractory depressed patients

    International Nuclear Information System (INIS)

    Kim, C. H.; Chung, Y. A.; Chae, J. H.; Oh, J. H.; Kim, S. H.; Sohn, H. S.; Chung, S. K.

    2005-01-01

    Imaging studies by repetitive transcranial magnetic stimulation (rTMS) demonstrates biological activities of the brain. The aim of this study was to investigate the patterns of regional cerebral blood flow (rCBF) after a series of therapeutic rTMS sessions. Nine patients with refractory depression who had not been responsive to appropriate pharmacotherapy over 1 year were randomly assigned to daily 1 Hz right-sided rTMS or 20 Hz left-sided rTMS sessions for over 3 weeks. Baseline and 3-week post-rTMS treatment SPECT images were obtained 40 minutes after intravenous injection of approximately 740925 MBq of Tc-99m ECD using a multi-detector scanner (ECAM plus; Siemens, Erlangen, Germany) equipped with a low-energy, fan-beam collimator. All patients showed a good clinical outcome. Statistically significant common increase in rCBF patterns was found in the fusiform gyrus of left temporal lobe, left hippocampus, left superior parietal lobule, superior frontal gyrus of right frontal lobe, right lateral globus pallidus and cingulated gyrus of both limbic lobes. And in the fusiform gyrus of left occipital lobe and middle frontal gyrus of right frontal lobe decreased uptake was seen compared to controls. Low-frequency rTMS on the right prefrontal cortex and high-frequency rTMS on the left prefrontal cortex for 3 weeks as an add-on regimen have increased activity in specific brain regions in patients with treatment refractory depression. Therapeutic TMS seems to influence distinct cortical regions, as well as different pathways, affecting rCBF in a homogeneous manner that is probably region dependent and illness related

  6. Effect of repetitive transcranial magnetic stimulation in drug resistant depressed patients

    International Nuclear Information System (INIS)

    Chung, Yong An; Yoo, Ie Ryung; Kang, Bong Joo; Chae, Jeong Ho; Lee, Hye Won; Moon, Hyun Jin; Kim, Sung Hoon; Sohn, Hyung Sun; Chung, Soo Kyo

    2007-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has recently been clinically applied in the treatment of drug resistant depressed patients. There are mixed findings about the efficacy of rTMS on depression. Furthermore, the influence of rTMS on the physiology of the brain is not clear. We prospectively evaluated changes of regional cerebral blood flow (rCBF) between pre- and post-rTMS treatment in patients with drug resistant depression. Twelve patients with drug-resistant depression (7 male, 5 female; age range; 19∼ 52 years; mean age: 29.3 ± 9.3 years) were given rTMS on right prefrontal lobe with low frequency (1 Hz) and on left prefrontal lobe with high frequency (20 Hz), with 20-minute-duration each day for 3 weeks. Tc-99m ECD brain perfusion SPECT was obtained before and after rTMS treatment. The changes of cerebral perfusion were analyzed using statistical parametric mapping (SPM; t=3.14, uncorrected ρ < 0.01, voxel = 100). Following areas showed significant increase in rCBF after 3 weeks rTMS treatment: the cingulate gyrus, fusiform gyrus of right temporal lobe, precuneus, and left lateral globus pallidus. Significant decrement was noted in the precental and middle frontal gyrus of right frontal lobe, and fusiform gyrus of left occipital lobe. Low-frequency rTMS on the right prefrontal cortex and high-frequency rTMS on the left prefrontal cortex for 3 weeks as an add-on regimen have increased and decreased rCBF in the specific brain regions in drug-resistant depressed patients. Further analyses correlating clinical characteristics and treatment paradigm with functional imaging data may be helpful in clarifying the pathophysiology of drug-resistant patients

  7. Experimental therapy of epilepsy with transcranial magnetic stimulation: lack of additional benefit with prolonged treatment

    Directory of Open Access Journals (Sweden)

    Brasil-Neto Joaquim P.

    2004-01-01

    Full Text Available OBJECTIVE: To investigate the effect of three months of low-frequency repetitive transcranial magnetic stimulation (rTMS treatment in intractable epilepsy. METHODS: Five patients (four males, one female; ages 6 to 50 years, were enrolled in the study; their epilepsy could not be controlled by medical treatment and surgery was not indicated. rTMS was performed twice a week for three months; patients kept records of seizure frequency for an equal period of time before, during, and after rTMS sessions. rTMS was delivered to the vertex with a round coil, at an intensity 5 % below motor threshold. During rTMS sessions, 100 stimuli (five series of 20 stimuli, with one-minute intervals between series were delivered at a frequency of 0.3 Hz. RESULTS: Mean daily number of seizures (MDNS decreased in three patients and increased in two during rTMS- one of these was treated for only one month; the best result was achieved in a patient with focal cortical dysplasia (reduction of 43.09 % in MDNS. In the whole patient group, there was a significant (p<0.01 decrease in MDNS of 22.8 %. CONCLUSION: Although prolonged rTMS treatment is safe and moderately decreases MDNS in a group of patients with intractable epilepsy, individual patient responses were mostly subtle and clinical relevance of this method is probably low. Our data suggest, however, that patients with focal cortical lesions may indeed benefit from this novel treatment. Further studies should concentrate on that patient subgroup.

  8. Transcranial magnetic stimulation in sleep fragmentation: a model to better understand sleep disorders.

    Science.gov (United States)

    Scalise, Anna; Pittaro-Cadore, Italo; Serafini, Anna; Simeoni, Sara; Fratticci, Lara; Ecoretti, Elisa; Gigli, Gian Luigi

    2014-11-01

    To investigate practice-dependent plasticity and cortical inhibition/excitability in good sleepers after a night of sleep fragmentation (SF), by means of transcranial magnetic stimulation (TMS). In basal condition (BC), after a full night of spontaneous sleep, and in fragmented condition (FC), after a fragmented night of sleep, motor evoked potential (MEP) amplitude, motor threshold (MT), silent period (SP), and intracortical inhibition were assessed. In both conditions subjects performed, also, a bimanual motor task: MEPs were recorded before and after exercise, and after rest. We evaluated the presence of post-exercise facilitation and delayed facilitation. Subjects reported their alertness level (Stanford Sleepiness Scale-SSS). MT and SSS were significantly increased in SF. Instead, no significant differences for MEP amplitude or SP or intracortical inhibition were found. In both conditions post-exercise facilitation and delayed facilitation were present. SF produces disruption of nocturnal sleep and increases daytime sleepiness. Confirmatory features of this clinical behaviour could be that in FC we observed a significant increase in SSS and in MT. SF was unable to modify cortical inhibition\\excitability and\\or to influence plasticity-related parameters. These results seem inconsistent with some of TMS alterations observed in sleep deprivation (SD) and restless legs syndrome (RLS). We suggest that SD and SF represent different phenomena that can depend on various networks acting on motor cortex. We speculate that alterations in cortical excitability found in RLS are intrinsically related to the underlying disease itself and are not instead directly associated with the SF present in RLS. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Adjunctive use of repetitive transcranial magnetic stimulation in depressed adolescents: a prospective, open pilot study.

    Science.gov (United States)

    Wall, Christopher A; Croarkin, Paul E; Sim, Leslie A; Husain, Mustafa M; Janicak, Philip G; Kozel, F Andrew; Emslie, Graham J; Dowd, Sheila M; Sampson, Shirlene M

    2011-09-01

    Depression is often a serious and debilitating illness in adolescents. Unfortunately, a significant number of adolescents do not respond to antidepressant medications or psychotherapy. Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment intervention shown to benefit depression in adults. This study considered rTMS as an adjunctive treatment in adolescents with major depressive disorder. This prospective, open, multicenter trial of active adjunctive rTMS was conducted with 8 adolescents with DSM-IV-TR major depressive disorder (MDD) that had not responded sufficiently to 2 adequate antidepressant medication trials. All subjects were maintained on a stable dose of a selective serotonin reuptake inhibitor during the trial. Thirty daily rTMS treatments were given 5 days per week over 6 to 8 weeks. rTMS was applied to the left dorsolateral prefrontal cortex (120% of motor threshold; 10 Hz; 4-second trains; 26-second intertrain interval; 75 trains) for a total of 3,000 stimulations per treatment session. Seven of 8 adolescents completed all 30 treatments. rTMS was well tolerated, and no significant safety issues were identified. Suicidal ideation was present at baseline in 3 of the adolescents, and it improved during treatment. The primary outcome measure was the Children's Depression Rating Scale-Revised (CDRS-R); results improved significantly from baseline (mean [SD]) (65.9 [6.6]) to treatment 10 (50.9 [12]), P < .02. The CDRS-R scores continued to improve through the rTMS treatment series at treatment 20 (40.1 [14]), P < .01; treatment 30 (32.6 [7.3]), P < .0001; and at 6-month follow-up (32.7 [3.8]), P < .0001. This prospective open trial suggests that rTMS is a safe, feasible, and potentially effective adjunctive therapy for treatment-resistant MDD in adolescents. clinicaltrials.gov Identifier: NCT00587639. © Copyright 2011 Physicians Postgraduate Press, Inc.

  10. Functional MRI-navigated repetitive transcranial magnetic stimulation over supplementary motor area in chronic tic disorders.

    Science.gov (United States)

    Wu, Steve W; Maloney, Thomas; Gilbert, Donald L; Dixon, Stephan G; Horn, Paul S; Huddleston, David A; Eaton, Kenneth; Vannest, Jennifer

    2014-01-01

    Open label studies have shown repetitive transcranial magnetic stimulation to be effective in reducing tics. To determine whether 8 sessions of continuous theta burst stimulation (cTBS) over supplementary motor area (SMA) given over 2 days may reduce tics and motor cortical network activity in Tourette syndrome/chronic tic disorders. This was a randomized (1:1), double-blind, sham-controlled trial of functional MRI (fMRI)-navigated, 30 Hz cTBS at 90% of resting motor threshold (RMT) over SMA in 12 patients ages 10-22 years. Comorbid ADHD (n = 8), OCD (n = 8), and stable concurrent medications (n = 9) were permitted. Neuro-navigation utilized each individual's event-related fMRI signal. Primary clinical and cortical outcomes were: 1) Yale Global Tic Severity Scale (YGTSS) at one week; 2) fMRI event-related signal in SMA and primary motor cortex (M1) during a finger-tapping motor task. Baseline characteristics were not statistically different between groups (age, current tic/OCD/ADHD severities, tic-years, number of prior medication trials, RMT). Mean YGTSS scores decreased in both active (27.5 ± 7.4 to 23.2 ± 9.8) and sham (26.8 ± 4.8 to 21.7 ± 7.7) groups. However, no significant difference in video-based tic severity rating was detected between the two groups. Two-day post-treatment fMRI activation during finger tapping decreased significantly in active vs. sham groups for SMA (P = 0.02), left M1 (P = 0.0004), and right M1 (P tic reduction at 7 days. Larger sample size and protocol modifications may be needed to produce clinically significant tic reduction beyond placebo effect. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Deep transcranial magnetic stimulation for the treatment of auditory hallucinations: a preliminary open-label study

    Directory of Open Access Journals (Sweden)

    Zangen Abraham

    2011-02-01

    Full Text Available Abstract Background Schizophrenia is a chronic and disabling disease that presents with delusions and hallucinations. Auditory hallucinations are usually expressed as voices speaking to or about the patient. Previous studies have examined the effect of repetitive transcranial magnetic stimulation (TMS over the temporoparietal cortex on auditory hallucinations in schizophrenic patients. Our aim was to explore the potential effect of deep TMS, using the H coil over the same brain region on auditory hallucinations. Patients and methods Eight schizophrenic patients with refractory auditory hallucinations were recruited, mainly from Beer Ya'akov Mental Health Institution (Tel Aviv university, Israel ambulatory clinics, as well as from other hospitals outpatient populations. Low-frequency deep TMS was applied for 10 min (600 pulses per session to the left temporoparietal cortex for either 10 or 20 sessions. Deep TMS was applied using Brainsway's H1 coil apparatus. Patients were evaluated using the Auditory Hallucinations Rating Scale (AHRS as well as the Scale for the Assessment of Positive Symptoms scores (SAPS, Clinical Global Impressions (CGI scale, and the Scale for Assessment of Negative Symptoms (SANS. Results This preliminary study demonstrated a significant improvement in AHRS score (an average reduction of 31.7% ± 32.2% and to a lesser extent improvement in SAPS results (an average reduction of 16.5% ± 20.3%. Conclusions In this study, we have demonstrated the potential of deep TMS treatment over the temporoparietal cortex as an add-on treatment for chronic auditory hallucinations in schizophrenic patients. Larger samples in a double-blind sham-controlled design are now being preformed to evaluate the effectiveness of deep TMS treatment for auditory hallucinations. Trial registration This trial is registered with clinicaltrials.gov (identifier: NCT00564096.

  12. Non-invasive mapping of bilateral motor speech areas using navigated transcranial magnetic stimulation and functional magnetic resonance imaging.

    Science.gov (United States)

    Könönen, Mervi; Tamsi, Niko; Säisänen, Laura; Kemppainen, Samuli; Määttä, Sara; Julkunen, Petro; Jutila, Leena; Äikiä, Marja; Kälviäinen, Reetta; Niskanen, Eini; Vanninen, Ritva; Karjalainen, Pasi; Mervaala, Esa

    2015-06-15

    Navigated transcranial magnetic stimulation (nTMS) is a modern precise method to activate and study cortical functions noninvasively. We hypothesized that a combination of nTMS and functional magnetic resonance imaging (fMRI) could clarify the localization of functional areas involved with motor control and production of speech. Navigated repetitive TMS (rTMS) with short bursts was used to map speech areas on both hemispheres by inducing speech disruption during number recitation tasks in healthy volunteers. Two experienced video reviewers, blinded to the stimulated area, graded each trial offline according to possible speech disruption. The locations of speech disrupting nTMS trials were overlaid with fMRI activations of word generation task. Speech disruptions were produced on both hemispheres by nTMS, though there were more disruptive stimulation sites on the left hemisphere. Grade of the disruptions varied from subjective sensation to mild objectively recognizable disruption up to total speech arrest. The distribution of locations in which speech disruptions could be elicited varied among individuals. On the left hemisphere the locations of disturbing rTMS bursts with reviewers' verification followed the areas of fMRI activation. Similar pattern was not observed on the right hemisphere. The reviewer-verified speech disruptions induced by nTMS provided clinically relevant information, and fMRI might explain further the function of the cortical area. nTMS and fMRI complement each other, and their combination should be advocated when assessing individual localization of speech network. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Transcranial magnetic motor evoked potentials and magnetic resonance imaging findings in paraplegic dogs with recovery of motor function.

    Science.gov (United States)

    Siedenburg, Johannes S; Wang-Leandro, Adriano; Amendt, Hanna-Luise; Rohn, Karl; Tipold, Andrea; Stein, Veronika M

    2018-03-22

    Transcranial magnetic motor evoked potentials (TMMEP) are associated with severity of clinical signs and magnetic resonance imaging (MRI) findings in dogs with spinal cord disease. That in initially paraplegic dogs with thoracolumbar intervertebral disc herniation (IVDH), MRI findings before surgery and TMMEPs obtained after decompressive surgery are associated with long-term neurological status and correlate with each other. Seventeen client-owned paraplegic dogs with acute thoracolumbar IVDH. Prospective observational study. TMMEPs were obtained from pelvic limbs and MRI (3T) of the spinal cord was performed at initial clinical presentation. Follow-up studies were performed ≤ 2 days after reappearance of motor function and 3 months later. Ratios of compression length, intramedullary hyperintensities' length (T2-weighted hyperintensity length ratio [T2WLR]), and lesion extension (T2-weighted-lesion extension ratio) in relation to the length of the 2nd lumbar vertebral body were calculated. TMMEPs could be elicited in 10/17 (59%) dogs at 1st and in 16/17 (94%) dogs at 2nd follow-up. Comparison of TMMEPs of 1st and 2nd follow-up showed significantly increased amplitudes (median from 0.19 to 0.45 mV) and decreased latencies (from 69.38 to 40.26 ms; P = .01 and .001, respectively). At 2nd follow-up latencies were significantly associated with ambulatory status (P = .024). T2WLR obtained before surgery correlated with latencies at 2nd follow-up (P = .04). TMMEP reflect motor function recovery after severe spinal cord injury. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  14. Right lower limb apraxia in a patient with left supplementary motor area infarction: intactness of the corticospinal tract confirmed by transcranial magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Min Cheol Chang

    2015-01-01

    Full Text Available We reported a 50-year-old female patient with left supplementary motor area infarction who presented right lower limb apraxia and investigated the possible causes using transcranial magnetic stimulation. The patient was able to walk and climb stairs spontaneously without any assistance at 3 weeks after onset. However, she was unable to intentionally move her right lower limb although she understood what she supposed to do. The motor evoked potential evoked by transcranial magnetic stimulation from the right lower limb was within the normal range, indicating that the corticospinal tract innervating the right lower limb was uninjured. Thus, we thought that her motor dysfunction was not induced by motor weakness, and confirmed her symptoms as apraxia. In addition, these results also suggest that transcranial magnetic stimulation is helpful for diagnosing apraxia.

  15. Influence of Distance and Illumination on Detection of Marks in Augmented Reality applied to Transcranial Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    José Soeiro

    2016-12-01

    Full Text Available The study was carried out while developing an Augmented Reality mobile application that represents 3D virtual models of the brain of a patient over the real image of the patient’s head. The main purpose of the application is to guide doctors during a non-invasive medical procedure called Transcranial Magnetic Stimulation that uses electromagnetic stimulation to treat neurological problems. The tracking of these markers have proven to be one of the more challenging components of such an application and we observe that lighting conditions and distance to the markers are two of the main factors that can influence their accurate recognition

  16. Increased probability of repetitive spinal motoneuron activation by transcranial magnetic stimulation after muscle fatigue in healthy subjects

    DEFF Research Database (Denmark)

    Andersen, Birgit; Felding, Ulrik Ascanius; Krarup, Christian

    2012-01-01

    probability of repetitive spinal MN activation during exercise even if some MNs failed to discharge by the brain stimulus. Here we used a modified TST (Quadruple stimulation; QuadS and Quintuple stimulation; QuintS) to examine the influence of fatiguing exercise on second and third MN discharges after...... the muscle is fatigued. Repetitive MN firing may provide an adaptive mechanism to maintain motor unit activation and task performance during sustained voluntary activity.......Triple stimulation technique (TST) has previously shown that transcranial magnetic stimulation (TMS) fails to activate a proportion of spinal motoneurons (MNs) during motor fatigue. The TST response depression without attenuation of the conventional motor evoked potential suggested increased...

  17. Dramatic Response of Resistant Obsessive Compulsive Disorder to Repeated Transcranial Magnetic Stimulation on Right Supplementary Motor Area

    Directory of Open Access Journals (Sweden)

    Ali Talaei

    2009-12-01

    Full Text Available The response rate to the treatment of obsessive compulsivedisorder (OCD is 21.6% to 61.3%, which shows a relativeresistance to current treatments and a need for noveltherapeutic approaches. Here we report a case of resistantOCD with fast and dramatic response to a relatively newmethod of repeated transcranial magnetic stimulation. In thismethod a pulse magnetic field emits from a coil over thesurface of the scalp to induce a localized electrical current inthe cortex below. Cortical activity can then be either inhibitedor stimulated. The patient was a 40-year-old woman withsevere OCD who admitted to our psychiatric hospital. She wastreated with 10 sessions of rTMS (110% intensity, 1 Hzfrequency and duration of 30 minutes per day / a total of 1200pulses per day on right supplementary motor area. Herimprovement evaluated serially with Yale Brown Scale. Bythe end of the 2nd day she reported a major improvement ofsymptoms. Dramatic improvement was observed in herobsessive and compulsive behaviors, and avoidance recoveredcompletely. She also reported significant improvement inability to control obsessive thoughts and impulses, and anxietysymptoms. Since repeated transcranial magnetic stimulation isa low risk method with almost no interaction with the commonmedications, as well as the faster response obtained by usingthis method, it can be used as an add-on treatment in resistantcases of OCD and even in the initial stages of this disorder.

  18. Repetitive Transcranial Magnetic Stimulation in Managing Mild Traumatic Brain Injury-Related Headaches.

    Science.gov (United States)

    Leung, Albert; Shukla, Shivshil; Fallah, Amir; Song, David; Lin, Lisa; Golshan, Shahrokh; Tsai, Alice; Jak, Amy; Polston, Greg; Lee, Roland

    2016-02-01

    Headache is one of the most common debilitating chronic pain conditions in either active or retired military personnel with mild traumatic brain injury (MTBI). This study assessed the effect of repetitive transcranial magnetic stimulation (rTMS) in alleviating MTBI-related headache (MTBI-HA). Veterans with MTBI-HA were randomized to receive either real rTMS (REAL group) at 10 hz for a total of 2000 pulses divided into 20 trains with one-sec inter-train interval or sham rTMS (SHAM group) at the left motor cortex (LMC) with brain magnetic resonance imaging neuronavigation guidance. Pretreatment, posttreatment one-week and four-week headache and neuropsychological assessments were conducted. Thirty veterans were screened and twenty four (21 men and 3 women with average year-old ± SD at 14.3 ± 12.6) subjects' data were analyzed. A two-factor (visit × treatment) repeated measures analysis of variance (RM-ANOVA) indicated a close to significant (p = 0.06) trend of interaction between pretreatment and posttreatment one-week assessment with the intensity of the persistent daily headache decreasing from 5.7 ± 1.9 to 2.2 ± 2.7 and 4.6 ± 1.3 to 3.5 ± 2.0 for the REAL and SHAM groups, respectively. Subsequent analyses indicated REAL group demonstrated a significantly (p = 0.041) higher % of reduction in persistent headache intensity than the SHAM group (56.3 ± 48.2% vs.15.4 ± 43.6%) at the posttreatment one-week assessment and the trend continued to the four-week assessment. Overall, a significantly (p = 0.035) higher percentage of the subjects in the REAL group (58.3%) demonstrated at least a 50% headache intensity reduction at posttreatment one-week assessment compared with the SHAM group (16.6%). The overall composite score of functionally debilitating headache exacerbation is significantly (p = 0.017) reduced in REAL group at the posttreatment four-week assessment in comparison with the SHAM group. No major sustained change in neuropsychological assessments was

  19. Seizure Induced by Deep Transcranial Magnetic Stimulation in an Adolescent with Depression.

    Science.gov (United States)

    Cullen, Kathryn R; Jasberg, Suzanne; Nelson, Brent; Klimes-Dougan, Bonnie; Lim, Kelvin O; Croarkin, Paul E

    2016-09-01

    Deep transcranial magnetic stimulation (TMS) with an H-1 coil was recently approved by the U.S. Food and Drug Administration (U.S. FDA) for treatment-resistant depression (TRD) in adults. Studies assessing the safety and effectiveness of deep TMS in adolescent TRD are lacking. The purpose of this brief report is to provide a case history of an adolescent enrolled in an investigational deep TMS protocol. A case history is described of the first participant of a sham-controlled clinical trial who had a seizure in the course of deep TMS with parameter settings extrapolated from the adult studies that led to US FDA approval (H-1 coil, 120% target stimulation intensity, 18 Hz, 55 trains of 2-second duration, total 1980 pulses). The participant was a 17-year-old unmedicated female, with no significant medical history and no history of seizures or of drug or alcohol use. Brain magnetic resonance imaging showed no structural abnormalities. She initially received sham, which was well tolerated. During active treatment sessions, titration began at 85% of motor threshold (MT) and increased by 5% per day. Her weekly MT measurements were stable. On her first day of 120% MT (8th active treatment), during the 48th train, the participant had a generalized, tonic-clonic seizure that lasted 90 seconds and resolved spontaneously. She had an emergency medicine evaluation and was discharged home without anticonvulsant medications. There were no further seizures reported at a 6-month follow-up. We report a deep TMS-induced generalized tonic-clonic seizure in an adolescent with TRD participating in a clinical trial. Given the demonstrated benefits of deep TMS for adult TRD, research investigating its use in adolescents with TRD is an important area. However, in light of this experience, additional precautions for adolescents should be considered. We propose that further dose-finding investigations are needed to refine adolescent-specific parameters that may be safe and effective for

  20. Transcranial magnetic stimulation in the semi-quantitative, pre-operative assessment of patients undergoing spinal deformity surgery.

    Science.gov (United States)

    Glasby, Michael A; Tsirikos, Athanasios I; Henderson, Lindsay; Horsburgh, Gillian; Jordan, Brian; Michaelson, Ciara; Adams, Christopher I; Garrido, Enrique

    2017-08-01

    To compare measurements of motor evoked potential latency stimulated either magnetically (mMEP) or electrically (eMEP) and central motor conduction time (CMCT) made pre-operatively in conscious patients using transcranial and intra-operatively using electrical cortical stimulation before and after successful instrumentation for the treatment of adolescent idiopathic scoliosis. A group initially of 51 patients with adolescent idiopathic scoliosis aged 12-19 years was evaluated pre-operatively in the outpatients' department with transcranial magnetic stimulation. The neurophysiological data were then compared statistically with intra-operative responses elicited by transcranial electrical stimulation both before and after successful surgical intervention. MEPs were measured as the cortically evoked compound action potentials of Abductor hallucis. Minimum F-waves were measured using conventional nerve conduction methods and the lower motor neuron conduction time was calculated and this was subtracted from MEP latency to give CMCT. Pre-operative testing was well tolerated in our paediatric/adolescent patients. No neurological injury occurred in any patient in this series. There was no significant difference in the values of mMEP and eMEP latencies seen pre-operatively in conscious patients and intra-operatively in patients under anaesthetic. The calculated quantities mCMCT and eCMCT showed the same statistical correlations as the quantities mMEP and eMEP latency. The congruency of mMEP and eMEP and of mCMCT and eCMCT suggests that these measurements may be used comparatively and semi-quantitatively for the comparison of pre-, intra-, and post-operative spinal cord function in spinal deformity surgery.

  1. Inhibitory repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex modulates early affective processing.

    Science.gov (United States)

    Zwanzger, Peter; Steinberg, Christian; Rehbein, Maimu Alissa; Bröckelmann, Ann-Kathrin; Dobel, Christian; Zavorotnyy, Maxim; Domschke, Katharina; Junghöfer, Markus

    2014-11-01

    The dorsolateral prefrontal cortex (dlPFC) has often been suggested as a key modulator of emotional stimulus appraisal and regulation. Therefore, in clinical trials, it is one of the most frequently targeted regions for non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). In spite of various encouraging reports that demonstrate beneficial effects of rTMS in anxiety disorders, psychophysiological studies exploring the underlying neural mechanisms are sparse. Here we investigated how inhibitory rTMS influences early affective processing when applied over the right dlPFC. Before and after rTMS or sham stimulation, subjects viewed faces with fearful or neutral expressions while whole-head magnetoencephalography (MEG) was recorded. Due to the disrupted functioning of the right dlPFC, visual processing in bilateral parietal, temporal, and occipital areas was amplified starting at around 90 ms after stimulus onset. Moreover, increased fear-specific activation was found in the right TPJ area in a time-interval between 110 and 170 ms. These neurophysiological effects were reflected in slowed reaction times for fearful, but not for neutral faces in a facial expression identification task while there was no such effect on a gender discrimination control task. Our study confirms the specific and important role of the dlPFC in regulation of early emotional attention and encourages future clinical research to use minimal invasive methods such as transcranial magnetic (TMS) or direct current stimulation (tDCS). Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Repetitive transcranial magnetic stimulation for pain after spinal cord injury: a systematic review and meta-analysis.

    Science.gov (United States)

    Gao, Feng; Chu, Hongyu; Li, Jianjun; Yang, Mingliang; DU, Liangjie; Li, Jun; Chen, Liang; Yang, Degang; Zhang, Hong; Chan, Chetwyn

    2017-10-01

    The evidence regarding efficiency of repetitive transcranial magnetic stimulation (rTMS) on relief of neuropathic pain (NP) in patients with prior spinal cord injury (SCI) is controversial. The current meta-analysis aimed to assess the efficacy of rTMS in pain relieve in patients suffering from SCI associated NP. Medline, PubMed, Cochrane Database, EMBASE, Google Scholar databases were searched for clinical studies on effects of rTMS treatment on NP caused by prior SCI published before March 14th, 2016 with various combinations of following key words: "transcranial magnetic stimulation," "spinal injury," "pain." Standardized difference in means with 95% confidence interval was calculated for the change of pain scores after rTMS or sham rTMS treatments. A total of two randomized controlled studies (RCTs) and 4 crossover RCTs were included in the present meta-analysis. The RCTs recruited a total of 27 patients. The crossover RCTs recruited a total of 100 patients. The combined standardized difference in means indicated that patients who received rTMS intervention had better pain relief than those who received sham rTMS intervention, however, the results did not reach statistical significance (standardized mean difference -0.607, 95% CI: -1.29 to 0.075, P=0.081). rTMS might reduce SCI associated neuropathic pain; however, further studies are required to support our conclusions.

  3. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa

    2010-01-01

    Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals, we applied 30 min of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate the ...... that left rPMd and SMG-AIP contribute toward dynamic control of actions and demonstrate that low-frequency rTMS can enhance functional coupling between task-relevant brain regions and improve some aspects of motor performance.......Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals, we applied 30 min of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate...... asked to covertly prepare motor responses as indicated by a directional cue presented 1 s before the target. On 20% of trials, the cue was invalid, requiring subjects to readjust their motor plan according to the target location. Compared with sham rTMS, real rTMS increased the number of correct...

  4. Optimal timing of pulse onset for language mapping with navigated repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Krieg, Sandro M; Tarapore, Phiroz E; Picht, Thomas; Tanigawa, Noriko; Houde, John; Sollmann, Nico; Meyer, Bernhard; Vajkoczy, Peter; Berger, Mitchel S; Ringel, Florian; Nagarajan, Srikantan

    2014-10-15

    Within the primary motor cortex, navigated transcranial magnetic stimulation (nTMS) has been shown to yield maps strongly correlated with those generated by direct cortical stimulation (DCS). However, the stimulation parameters for repetitive nTMS (rTMS)-based language mapping are still being refined. For this purpose, the present study compares two rTMS protocols, which differ in the timing of pulse train onset relative to picture presentation onset during object naming. Results were the correlated with DCS language mapping during awake surgery. Thirty-two patients with left-sided perisylvian tumors were examined by rTMS prior to awake surgery. Twenty patients underwent rTMS pulse trains starting at 300 ms after picture presentation onset (delayed TMS), whereas another 12 patients received rTMS pulse trains starting at the picture presentation onset (ONSET TMS). These rTMS results were then evaluated for correlation with intraoperative DCS results as gold standard in terms of differential consistencies in receiver operating characteristics (ROC) statistics. Logistic regression analysis by protocols and brain regions were conducted. Within and around Broca's area, there was no difference in sensitivity (onset TMS: 100%, delayed TMS: 100%), negative predictive value (NPV) (onset TMS: 100%, delayed TMS: 100%), and positive predictive value (PPV) (onset TMS: 55%, delayed TMS: 54%) between the two protocols compared to DCS. However, specificity differed significantly (onset TMS: 67%, delayed TMS: 28%). In contrast, for posterior language regions, such as supramarginal gyrus, angular gyrus, and posterior superior temporal gyrus, early pulse train onset stimulation showed greater specificity (onset TMS: 92%, delayed TMS: 20%), NPV (onset TMS: 92%, delayed TMS: 57%) and PPV (onset TMS: 75%, delayed TMS: 30%) with comparable sensitivity (onset TMS: 75%, delayed TMS: 70%). Logistic regression analysis also confirmed the greater fit of the predictions by rTMS that had the

  5. TMSEEG: A MATLAB-Based Graphical User Interface for Processing Electrophysiological Signals during Transcranial Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Sravya Atluri

    2016-10-01

    Full Text Available Concurrent recording of electroencephalography (EEG during transcranial magnetic stimulation (TMS is an emerging and powerful tool for studying brain health and function. Despite a growing interest in adaptation of TMS-EEG across neuroscience disciplines, its wide-spread utility is limited by signal processing challenges. These challenges arise due to the nature of TMS and the sensitivity of EEG to artifacts that often mask TMS-evoked potentials (TEPs. With an increase in the complexity of data processing methods and a growing interest in multi-site data integration, analysis of TMS-EEG data requires the development of a standardized method to recover TEPs from various sources of artifacts. This paper introduces TMSEEG, an open-source MATLAB application comprised of multiple algorithms organized to facilitate a step-by-step procedure for TMS-EEG signal processing. Using a modular design and interactive GUIs, this toolbox aims to streamline TMS-EEG signal processing for both novice and experienced users. Specifically, TMSEEG provides (i targeted removal of TMS-induced and general EEG artifacts, (ii a step-by-step modular workflow with flexibility to modify existing algorithms and add customized algorithms, (iii a comprehensive display and quantification of artifacts, (iv quality control check points with visual feedback of TEPs throughout the data processing workflow, and (v capability to label and store a database of artifacts. In addition to these features, the software architecture of TMSEEG ensures minimal user effort in initial setup and configuration of parameters for each processing step. This is partly accomplished through a close integration with EEGLAB, a widely used open-source toolbox for EEG signal processing. In this paper we introduce TMSEEG, validate its features, and demonstrate its application in extracting TEPs across several single- and multi-pulse TMS protocols. As the first open-source GUI-based pipeline for TMS-EEG signal

  6. TMSEEG: A MATLAB-Based Graphical User Interface for Processing Electrophysiological Signals during Transcranial Magnetic Stimulation.

    Science.gov (United States)

    Atluri, Sravya; Frehlich, Matthew; Mei, Ye; Garcia Dominguez, Luis; Rogasch, Nigel C; Wong, Willy; Daskalakis, Zafiris J; Farzan, Faranak

    2016-01-01

    Concurrent recording of electroencephalography (EEG) during transcranial magnetic stimulation (TMS) is an emerging and powerful tool for studying brain health and function. Despite a growing interest in adaptation of TMS-EEG across neuroscience disciplines, its widespread utility is limited by signal processing challenges. These challenges arise due to the nature of TMS and the sensitivity of EEG to artifacts that often mask TMS-evoked potentials (TEP)s. With an increase in the complexity of data processing methods and a growing interest in multi-site data integration, analysis of TMS-EEG data requires the development of a standardized method to recover TEPs from various sources of artifacts. This article introduces TMSEEG, an open-source MATLAB application comprised of multiple algorithms organized to facilitate a step-by-step procedure for TMS-EEG signal processing. Using a modular design and interactive graphical user interface (GUI), this toolbox aims to streamline TMS-EEG signal processing for both novice and experienced users. Specifically, TMSEEG provides: (i) targeted removal of TMS-induced and general EEG artifacts; (ii) a step-by-step modular workflow with flexibility to modify existing algorithms and add customized algorithms; (iii) a comprehensive display and quantification of artifacts; (iv) quality control check points with visual feedback of TEPs throughout the data processing workflow; and (v) capability to label and store a database of artifacts. In addition to these features, the software architecture of TMSEEG ensures minimal user effort in initial setup and configuration of parameters for each processing step. This is partly accomplished through a close integration with EEGLAB, a widely used open-source toolbox for EEG signal processing. In this article, we introduce TMSEEG, validate its features and demonstrate its application in extracting TEPs across several single- and multi-pulse TMS protocols. As the first open-source GUI-based pipeline

  7. TMSEEG: A MATLAB-Based Graphical User Interface for Processing Electrophysiological Signals during Transcranial Magnetic Stimulation

    Science.gov (United States)

    Atluri, Sravya; Frehlich, Matthew; Mei, Ye; Garcia Dominguez, Luis; Rogasch, Nigel C.; Wong, Willy; Daskalakis, Zafiris J.; Farzan, Faranak

    2016-01-01

    Concurrent recording of electroencephalography (EEG) during transcranial magnetic stimulation (TMS) is an emerging and powerful tool for studying brain health and function. Despite a growing interest in adaptation of TMS-EEG across neuroscience disciplines, its widespread utility is limited by signal processing challenges. These challenges arise due to the nature of TMS and the sensitivity of EEG to artifacts that often mask TMS-evoked potentials (TEP)s. With an increase in the complexity of data processing methods and a growing interest in multi-site data integration, analysis of TMS-EEG data requires the development of a standardized method to recover TEPs from various sources of artifacts. This article introduces TMSEEG, an open-source MATLAB application comprised of multiple algorithms organized to facilitate a step-by-step procedure for TMS-EEG signal processing. Using a modular design and interactive graphical user interface (GUI), this toolbox aims to streamline TMS-EEG signal processing for both novice and experienced users. Specifically, TMSEEG provides: (i) targeted removal of TMS-induced and general EEG artifacts; (ii) a step-by-step modular workflow with flexibility to modify existing algorithms and add customized algorithms; (iii) a comprehensive display and quantification of artifacts; (iv) quality control check points with visual feedback of TEPs throughout the data processing workflow; and (v) capability to label and store a database of artifacts. In addition to these features, the software architecture of TMSEEG ensures minimal user effort in initial setup and configuration of parameters for each processing step. This is partly accomplished through a close integration with EEGLAB, a widely used open-source toolbox for EEG signal processing. In this article, we introduce TMSEEG, validate its features and demonstrate its application in extracting TEPs across several single- and multi-pulse TMS protocols. As the first open-source GUI-based pipeline

  8. Measurement of voluntary activation of the back muscles using transcranial magnetic stimulation.

    Science.gov (United States)

    Lagan, James; Lang, Peter; Strutton, Paul H

    2008-12-01

    Twitch interpolation using transcranial magnetic stimulation (TMS) has recently been used to measure the level of drive from the motor cortex to contracting muscles of the upper and lower limbs, termed voluntary activation. It has yet to be used to assess voluntary activation in trunk muscles. The aim of this study was to assess the feasibility of using TMS to measure voluntary activation in back muscles. Sixteen healthy subjects performed a series of brief maximal and submaximal isometric contractions of the back extensors during which TMS was delivered to the motor cortex. The evoked (superimposed) twitch was measured using dynamometry and simultaneous surface electromyographic (EMG) recordings were taken from the left and right erector spinae at vertebral level T12. Voluntary activation was derived using the expression: (1-superimposed twitch amplitude/resting twitch amplitude)x100. The resting twitch amplitude was estimated by extrapolation of the linear correlation between voluntary torque and superimposed twitch amplitude to zero torque. The relationship between superimposed twitch size and voluntary contraction strength for contraction strengths of 50-100% MVC was linear but regression revealed variability between subjects. When data were included from those subjects with a good linear regression fit a strong linear relationship was found for the group means between voluntary contraction strength and voluntary activation (r(2)=1) and superimposed twitch size (r(2)=0.99) for contraction strengths of 50-100% MVC. Voluntary activation was found to be less than maximal (67.71+/-5.22%) during maximal efforts. Time-to-peak amplitude decreased linearly with increasing voluntary torque. The amplitudes of the motor evoked potentials (MEPs) increased with increasing voluntary torque. Twitch interpolation using TMS can be used to quantify voluntary activation in back extensors. The results of this study reveal that neural drive to the back extensors during strong

  9. Repetitive Transcranial Magnetic Stimulation (rTMS) Therapy in Parkinson Disease: A Meta-Analysis.

    Science.gov (United States)

    Wagle Shukla, Aparna; Shuster, Jonathan J; Chung, Jae Woo; Vaillancourt, David E; Patten, Carolynn; Ostrem, Jill; Okun, Michael S

    2016-04-01

    Several studies have reported repetitive transcranial magnetic stimulation (rTMS) therapy as an effective treatment for the control of motor symptoms in Parkinson disease. The objective of the study is to quantify the overall efficacy of this treatment. Systematic review and meta-analysis. We reviewed the literature on clinical rTMS trials in Parkinson disease since the technique was introduced in 1980. We used the following databases: MEDLINE, Web of Science, Cochrane, and CINAHL. Patients with Parkinson disease who were participating in prospective clinical trials that included an active arm and a control arm and change in motor scores on Unified Parkinson's Disease Rating Scale as the primary outcome. We pooled data from 21 studies that met these criteria. We then analyzed separately the effects of low- and high-frequency rTMS on clinical motor improvements. The overall pooled mean difference between treatment and control groups in the Unified Parkinson's Disease Rating Scale motor score was significant (4.0 points, 95% confidence interval, 1.5, 6.7; P = .005). rTMS therapy was effective when low-frequency stimulation (≤ 1 Hz) was used with a pooled mean difference of 3.3 points (95% confidence interval 1.6, 5.0; P = .005). There was a trend for significance when high-frequency stimulation (≥ 5 Hz) studies were evaluated with a pooled mean difference of 3.9 points (95% confidence interval, -0.7, 8.5; P = .08). rTMS therapy demonstrated benefits at short-term follow-up (immediately after a treatment protocol) with a pooled mean difference of 3.4 points (95% confidence interval, 0.3, 6.6; P = .03) as well as at long-term follow-up (average follow-up 6 weeks) with mean difference of 4.1 points (95% confidence interval, -0.15, 8.4; P = .05). There were insufficient data to statistically analyze the effects of rTMS when we specifically examined bradykinesia, gait, and levodopa-induced dyskinesia using quantitative methods. rTMS therapy in patients with Parkinson

  10. [Changes of somatosensory and transcranial magnetic stimulation motor evoked potentials in experimental spinal cord injury].

    Science.gov (United States)

    Hou, Yong; Nie, Lin; Liu, Li-hong; Shao, Jun; Yuan, Yong-jian

    2008-03-18

    To study the changes of somatosensory evoked potential (SEP) and transcranial magnetic simulation motor evoked potential (TMS-MEP) in experimental spinal cord injury (SCI). Thirty-two rabbits were randomly divided into 4 equal groups. All rabbits were anesthetized for 90 min. A group (Group A) underwent only laminectomy of T12 without SCI, stimulation with different intensities was used to induce SEP and TMS-MEP to determine the most appropriate stimulation intensity. The EPs were recorded before and after the operation. The other 3 groups underwent laminectomy of T12 to expose the dura, and a spinal cord compressing apparatus weighing 40 g was put on the intact dura and dorsal surface of spinal cord underneath for 5, 15, and 30 min respectively (Groups B, C, and D). SEP and TMS-MEP were detected after anesthesia, after exposure of spinal cord, and 5 and 30 min, 1 and 6 h, and 1, 3, and 7 d. The latency and amplitude of each wave were measured. The data were analyzed by analysis of variance, t-test and linear correlation. Tarlov behavior score was used to assess the motor function before the operation and 1, 3, and 7 days after SCI. It was found that 100% intensity stimulus obtained stable and reliable MEP waves. Anesthetic did not influence the EPs. The amplitude of SEP began to decrease 5 min after SCI and the latency began to increase 30 min after SCI. And both the amplitude and latency, especially the former, of MEP began to significantly change 5 min after SCI. The latency levels of SEP and MEP increased and the amplitude decreased after compression time-dependently during a certain range of time (all P TMS-MEP are very sensitive to SCI, in particular, the change of amplitude is more sensitive then the latency change and can more accurately reflect the degree of SCI. Combination of SEP and TMS-MEP objectively reflects the SCI degree. EP measurement, as a noninvasive technique, has great value in monitoring spinal cord function.

  11. Repetitive Transcranial Magnetic Stimulation Educes Frequency-Specific Causal Relationships in the Motor Network.

    Science.gov (United States)

    Salinas, Felipe S; Franklin, Crystal; Narayana, Shalini; Szabó, C Ákos; Fox, Peter T

    2016-01-01

    Repetitive transcranial magnetic stimulation (rTMS) has the potential to treat brain disorders by modulating the activity of disease-specific brain networks, yet the rTMS frequencies used are delivered in a binary fashion - excitatory (>1 Hz) and inhibitory (≤1 Hz). To assess the effective connectivity of the motor network at different rTMS stimulation rates during positron-emission tomography (PET) and confirm that not all excitatory rTMS frequencies act on the motor network in the same manner. We delivered image-guided, supra-threshold rTMS at 3 Hz, 5 Hz, 10 Hz, 15 Hz and rest (in separate randomized sessions) to the primary motor cortex (M1) of the lightly anesthetized baboon during PET imaging. Each rTMS/PET session was analyzed using normalized cerebral blood flow (CBF) measurements. Path analysis - using structural equation modeling (SEM) - was employed to determine the effective connectivity of the motor network at all rTMS frequencies. Once determined, the final model of the motor network was used to assess any differences in effective connectivity at each rTMS frequency. The exploratory SEM produced a very well fitting final network model (χ(2) = 18.04, df = 21, RMSEA = 0.000, p = 0.647, TLI = 1.12) using seven nodes of the motor network. 5 Hz rTMS produced the strongest path coefficients in four of the seven connections, suggesting that this frequency is the optimal rTMS frequency for stimulation the motor network (as a whole); however, the premotor cerebellum connection was optimally stimulated at 10 Hz rTMS and the supplementary motor area caudate connection was optimally driven at 15 Hz rTMS. We have demonstrated that 1) 5 Hz rTMS revealed the strongest path coefficients (i.e. causal influence) on the nodes of the motor network, 2) stimulation at "excitatory" rTMS frequencies did not produce increased CBF in all nodes of the motor network, 3) specific rTMS frequencies may be used to target specific none

  12. Primary Motor Cortex Excitability in Karate Athletes: A Transcranial Magnetic Stimulation Study.

    Science.gov (United States)

    Monda, Vincenzo; Valenzano, Anna; Moscatelli, Fiorenzo; Salerno, Monica; Sessa, Francesco; Triggiani, Antonio I; Viggiano, Andrea; Capranica, Laura; Marsala, Gabriella; De Luca, Vincenzo; Cipolloni, Luigi; Ruberto, Maria; Precenzano, Francesco; Carotenuto, Marco; Zammit, Christian; Gelzo, Monica; Monda, Marcellino; Cibelli, Giuseppe; Messina, Giovanni; Messina, Antonietta

    2017-01-01

    Purpose: The mechanisms involved in the coordination of muscle activity are not completely known: to investigate adaptive changes in human motor cortex Transcranial magnetic stimulation (TMS) was often used. The sport models are frequently used to study how the training may affect the corticospinal system excitability: Karate represents a valuable sport model for this kind of investigations for its high levels of coordination required to athletes. This study was aimed at examining possible changes in the resting motor threshold (rMT) and in the corticospinal response in karate athletes, and at determining whether athletes are characterized by a specific value of rMT. Methods: We recruited 25 right-handed young karate athletes and 25 matched non-athletes. TMS was applied to primary motor cortex (M1). Motor evoked potential (MEP) were recorded by two electrodes placed above the first dorsal interosseous (FDI) muscle. We considered MEP latencies and amplitudes at rMT, 110% of rMT, and 120% of rMT. Results: The two groups were similar for age ( p > 0.05), height ( p > 0.05) and body mass ( p > 0.05). The TMS had a 70-mm figure-of-eight coil and a maximum output of 2.2 T, placed over the left motor cortex. During the stimulation, a mechanical arm kept the coil tangential to the scalp, with the handle at 45° respect to the midline. The SofTaxic navigator system (E.M.S. Italy, www.emsmedical.net) was used in order to correctly identifying and repeating the stimulation for every subject. Compared to non-athletes, athletes showed a lower resting motor threshold ( p < 0.001). Furthermore, athletes had a lower MEP latency ( p < 0.001) and a higher MEP amplitude ( p < 0.001) compared to non-athletes. Moreover, a ROC curve for rMT was found significant (area: 0.907; sensitivity 84%, specificity 76%). Conclusions: As the main finding, the present study showed significant differences in cortical excitability between athletes and non-athletes. The training can improve cortical

  13. Striatal dopamine release induced by repetitive transcranial magnetic stimulation over dorsolateral prefrontal cortex: effect of aging

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Seong Ae; Cho, Sang Soo; Yoon, Eun Jin; Kim, Ji Sun; Lee, Byung Chul; Kim, Yu Kyeong; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    We previously demonstrated dopamine (DA) release in the bilateral striatal regions following prefrontal repetitive transcranial magnetic stimulation (rTMS) in young subjects. Several lines of evidence support substantial age-related changes in human dopaminergic neurotransmission. One possible explanation is alteration of cortico striatal neural connection with aging. Therefore, we investigated how frontal activation by rTMS influences striatal DA release in the elderly with SPECT measurements of striatal binding of [123I]iodobenzamide (lBZM), a DA D2 receptor radioligand that is sensitive to endogenous DA. Five healthy elderly male subjects (age, 64 3 y) were studied with brain [123I]IBZM SPECT under three conditions (resting, sham stimulation, and active rTMS over left dorsolateral prefrontal cortex (DLPFC)), while receiving a bolus plus constant infusion of [123I]IBZM. rTMS session consisted of three blocks. In each block, 15 trains of 2 sec duration were delivered with 10 Hz stimulation frequency and 100% motor threshold. Striatal V3', calculated as (striatal - occipital)/occipital radioactivity, was measured under equilibrium condition at baseline and after sham and active rTMS. Sham stimulation did not affect striatal V3'. rTMS over left DLPFC induced no significant change in V3' in the right striatum compared with baseline condition (0.91 0.25 vs. 0.96 0.25, P = NS). Interestingly, left striatal V3' showed a significant increase after rTMS over left DLPFC compared with sham condition (1.09 0.33 vs. 0.93 0.27, P < 0.05; 17.0 11.1% increase). These results are discrepant from previous ones from young subjects, who showed frontal rTMS-induced reduction of striatal V3', indicating rTMS-induced striatal DA release. We found no significant striatal DA release induced by rTMS over DLPFC in healthy elderly subjects using in vivo binding competition techniques. These results may support an altered cortico striatal circuit in normal aging.

  14. Interhemispheric Inhibition Induced by Transcranial Magnetic Stimulation Over Primary Sensory Cortex.

    Science.gov (United States)

    Iwata, Yasuyuki; Jono, Yasutomo; Mizusawa, Hiroki; Kinoshita, Atsushi; Hiraoka, Koichi

    2016-01-01

    The present study investigated whether the long-interval interhemispheric inhibition (LIHI) is induced by the transcranial magnetic stimulation over the primary sensory area (S1-TMS) without activation of the conditioning side of the primary motor area (M1) contributing to the contralateral motor evoked potential (MEP), whether the S1-TMS-induced LIHI is dependent on the status of the S1 modulated by the tactile input, and whether the pathways mediating the LIHI are different from those mediating the M1-TMS-induced LIHI. In order to give the TMS over the S1 without eliciting the MEP, the intensity of the S1-TMS was adjusted to be the sub-motor-threshold level and the trials with the MEP response elicited by the S1-TMS were discarded online. The LIHI was induced by the S1-TMS given 40 ms before the test TMS in the participants with the attenuation of the tactile perception of the digit stimulation (TPDS) induced by the S1-TMS, indicating that the LIHI is induced by the S1-TMS without activation of the conditioning side of the M1 contributing to the contralateral MEP in the participants in which the pathways mediating the TPDS is sensitive to the S1-TMS. The S1-TMS-induced LIHI was positively correlated with the attenuation of the TPDS induced by the S1-TMS, indicating that the S1-TMS-induced LIHI is dependent on the effect of the S1-TMS on the pathways mediating the TPDS at the S1. In another experiment, the effect of the digit stimulation given before the conditioning TMS on the S1- or M1-TMS-induced LIHI was examined. The digit stimulation produces tactile input to the S1 causing change in the status of the S1. The S1-TMS-induced LIHI was enhanced when the S1-TMS was given in the period in which the tactile afferent volley produced by the digit stimulation just arrived at the S1, while the LIHI induced by above-motor-threshold TMS over the contralateral M1 was not enhanced by the tactile input. Thus, the S1-TMS-induced LIHI is dependent on the status of the S1

  15. Repetitive transcranial magnetic stimulation induces oscillatory power changes in chronic tinnitus

    Directory of Open Access Journals (Sweden)

    Martin eSchecklmann

    2015-10-01

    Full Text Available Chronic tinnitus is associated with neuroplastic changes in auditory and non-auditory cortical areas. About ten years ago, repetitive transcranial magnetic stimulation (rTMS of auditory and prefrontal cortex was introduced as potential treatment for tinnitus. The resulting changes in tinnitus loudness are interpreted in the context of rTMS induced activity changes (neuroplasticity. Here, we investigate the effect of single rTMS sessions on oscillatory power to probe the capacity of rTMS to interfere with tinnitus-specific cortical plasticity. We measured 20 patients with bilateral chronic tinnitus and 20 healthy controls comparable for age, sex, handedness, and hearing level with a 63-channel EEG system. Educational level, intelligence, depressivity and hyperacusis were controlled for by analysis of covariance. Different rTMS protocols were tested: Left and right temporal and left and right prefrontal cortices were each stimulated with 200 pulses at 1Hz and with an intensity of 60% stimulator output. Stimulation of central parietal cortex with 6-fold reduced intensity (inverted passive-cooled coil served as sham condition. Before and after each rTMS protocol five minutes of resting state EEG were recorded. The order of rTMS protocols was randomized over two sessions with one week interval in between.Analyses on electrode level showed that people with and without tinnitus differed in their response to left temporal and right frontal stimulation. In tinnitus patients left temporal rTMS decreased frontal theta and delta and increased beta2 power, whereas right frontal rTMS decreased right temporal beta3 and gamma power. No changes or increases were observed in the control group. Only non-systematic changes in tinnitus loudness were induced by single sessions of rTMS.This is the first study to show tinnitus-related alterations of neuroplasticity that were specific to stimulation site and oscillatory frequency. The observed effects can be interpreted

  16. Repetitive transcranial magnetic stimulation induces oscillatory power changes in chronic tinnitus

    Science.gov (United States)

    Schecklmann, Martin; Lehner, Astrid; Gollmitzer, Judith; Schmidt, Eldrid; Schlee, Winfried; Langguth, Berthold

    2015-01-01

    Chronic tinnitus is associated with neuroplastic changes in auditory and non-auditory cortical areas. About 10 years ago, repetitive transcranial magnetic stimulation (rTMS) of auditory and prefrontal cortex was introduced as potential treatment for tinnitus. The resulting changes in tinnitus loudness are interpreted in the context of rTMS induced activity changes (neuroplasticity). Here, we investigate the effect of single rTMS sessions on oscillatory power to probe the capacity of rTMS to interfere with tinnitus-specific cortical plasticity. We measured 20 patients with bilateral chronic tinnitus and 20 healthy controls comparable for age, sex, handedness, and hearing level with a 63-channel electroencephalography (EEG) system. Educational level, intelligence, depressivity and hyperacusis were controlled for by analysis of covariance. Different rTMS protocols were tested: Left and right temporal and left and right prefrontal cortices were each stimulated with 200 pulses at 1 Hz and with an intensity of 60% stimulator output. Stimulation of central parietal cortex with 6-fold reduced intensity (inverted passive-cooled coil) served as sham condition. Before and after each rTMS protocol 5 min of resting state EEG were recorded. The order of rTMS protocols was randomized over two sessions with 1 week interval in between. Analyses on electrode level showed that people with and without tinnitus differed in their response to left temporal and right frontal stimulation. In tinnitus patients left temporal rTMS decreased frontal theta and delta and increased beta2 power, whereas right frontal rTMS decreased right temporal beta3 and gamma power. No changes or increases were observed in the control group. Only non-systematic changes in tinnitus loudness were induced by single sessions of rTMS. This is the first study to show tinnitus-related alterations of neuroplasticity that were specific to stimulation site and oscillatory frequency. The observed effects can be

  17. A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS in Anorexia Nervosa.

    Directory of Open Access Journals (Sweden)

    Jessica McClelland

    Full Text Available Anorexia nervosa (AN is associated with morbid fear of fatness, extreme food restriction and altered self-regulation. Neuroimaging data implicate fronto-striatal circuitry, including the dorsolateral prefrontal cortex (DLPFC.In this double-blind parallel group study, we investigated the effects of one session of sham-controlled high-frequency repetitive transcranial magnetic stimulation (rTMS to the left DLPFC (l-DLPFC in 60 individuals with AN. A food exposure task was administered before and after the procedure to elicit AN-related symptoms.The primary outcome measure was 'core AN symptoms', a variable which combined several subjective AN-related experiences. The effects of rTMS on other measures of psychopathology (e.g. mood, temporal discounting (TD; intertemporal choice behaviour and on salivary cortisol concentrations were also investigated. Safety, tolerability and acceptability were assessed.Fourty-nine participants completed the study. Whilst there were no interaction effects of rTMS on core AN symptoms, there was a trend for group differences (p = 0.056: after controlling for pre-rTMS scores, individuals who received real rTMS had reduced symptoms post-rTMS and at 24-hour follow-up, relative to those who received sham stimulation. Other psychopathology was not altered differentially following real/sham rTMS. In relation to TD, there was an interaction trend (p = 0.060: real versus sham rTMS resulted in reduced rates of TD (more reflective choice behaviour. Salivary cortisol concentrations were unchanged by stimulation. rTMS was safe, well-tolerated and was considered an acceptable intervention.This study provides modest evidence that rTMS to the l-DLPFC transiently reduces core symptoms of AN and encourages prudent decision making. Importantly, individuals with AN considered rTMS to be a viable treatment option. These findings require replication in multiple-session studies to evaluate therapeutic efficacy

  18. Primary Motor Cortex Excitability in Karate Athletes: A Transcranial Magnetic Stimulation Study

    Directory of Open Access Journals (Sweden)

    Vincenzo Monda

    2017-09-01

    Full Text Available Purpose: The mechanisms involved in the coordination of muscle activity are not completely known: to investigate adaptive changes in human motor cortex Transcranial magnetic stimulation (TMS was often used. The sport models are frequently used to study how the training may affect the corticospinal system excitability: Karate represents a valuable sport model for this kind of investigations for its high levels of coordination required to athletes. This study was aimed at examining possible changes in the resting motor threshold (rMT and in the corticospinal response in karate athletes, and at determining whether athletes are characterized by a specific value of rMT.Methods: We recruited 25 right-handed young karate athletes and 25 matched non-athletes. TMS was applied to primary motor cortex (M1. Motor evoked potential (MEP were recorded by two electrodes placed above the first dorsal interosseous (FDI muscle. We considered MEP latencies and amplitudes at rMT, 110% of rMT, and 120% of rMT.Results: The two groups were similar for age (p > 0.05, height (p > 0.05 and body mass (p > 0.05. The TMS had a 70-mm figure-of-eight coil and a maximum output of 2.2 T, placed over the left motor cortex. During the stimulation, a mechanical arm kept the coil tangential to the scalp, with the handle at 45° respect to the midline. The SofTaxic navigator system (E.M.S. Italy, www.emsmedical.net was used in order to correctly identifying and repeating the stimulation for every subject. Compared to non-athletes, athletes showed a lower resting motor threshold (p < 0.001. Furthermore, athletes had a lower MEP latency (p < 0.001 and a higher MEP amplitude (p < 0.001 compared to non-athletes. Moreover, a ROC curve for rMT was found significant (area: 0.907; sensitivity 84%, specificity 76%.Conclusions: As the main finding, the present study showed significant differences in cortical excitability between athletes and non-athletes. The training can improve cortical

  19. Bilateral Transcranial Magnetic Stimulation of the Prefrontal Cortex reduces cocaine intake: a pilot study.

    Directory of Open Access Journals (Sweden)

    Corinna Bolloni

    2016-08-01

    Full Text Available Background: Chronic cocaine consumption is associated to a decrease in mesolimbic dopamine transmission that maintains drug intake. Transcranial Magnetic Stimulation (TMS is gaining reliability a useful therapeutic tool in drug addiction since it can modulate cortico-limbic activity resulting in reduction of drug craving. Aims: In the present study we investigated the therapeutic effect of bilateral TMS of prefrontal cortex (PFC in reducing cocaine intake, in a sample of treatment-seeking patients with current cocaine use disorder (DSM-V. Methods: 10 cocaine addicts (DSM-V were randomly assigned to the active or sham stimulation protocol in a double-blind experimental design. Twelve repetitive TMS (rTMS sessions were administered 3 times a week for 4 weeks at 100% of motor threshold, over bilateral PFC. Cocaine intake (ng/mg was assessed by hair analysis at baseline (before treatment, T0, after one month (end of treatment, T1, 3 (T2 and 6 (T3 months later. All subjects received psychological support weekly. Results: The two-way ANOVA for repeated measures did not show a significant effect of the interaction between time and treatment (F4,32= 0.35; p=.87. Despite that result indicated no difference in the effect of the two conditions (active vs sham along time, a decreasing trend in cocaine consumption in active TMS group (F3,23=3.42; p=.04 vs sham (F3,15=1.88; p=.20 was observed when we performed exploratory analysis with time as factor . Indeed, Post-hoc comparisons showed a significant reduction in the amount of cocaine detected from the onset to three months later (T0-T2; p=.02 and to the end of treatment (T0-T3; p=.01 in addicts from the active group. Conclusions: Bilateral rTMS of PFC at 10 Hz did not show a significant effect on cocaine intake compared to sham. However, a long-term reduction in cocaine intake in active TMS treated patients was observed when we considered the time as factor. Further studies are required to confirm these

  20. Online Transcranial Magnetic Stimulation Protocol for Measuring Cortical Physiology Associated with Response Inhibition.

    Science.gov (United States)

    Guthrie, Michael D; Gilbert, Donald L; Huddleston, David A; Pedapati, Ernest V; Horn, Paul S; Mostofsky, Stewart H; Wu, Steve W

    2018-02-08

    We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) characterization of primary motor cortex (M1) excitability and inhibition. Motor response inhibition prevents unwanted actions and is abnormal in several neuropsychiatric conditions. TMS is a non-invasive technology that can quantify M1 excitability and inhibition using single- and paired-pulse protocols and can be precisely timed to study cortical physiology with high temporal resolution. We modified the original Slater-Hammel (S-H) stop signal task to create a "racecar" version with TMS pulses time-locked to intra-trial events. This task is self-paced, with each trial initiating after a button push to move the racecar towards the 800 ms target. GO trials require a finger-lift to stop the racecar just before this target. Interspersed randomly are STOP trials (25%) during which the dynamically adjusted stop signal prompts subjects to prevent finger-lift. For GO trials, TMS pulses were delivered at 650 ms after trial onset; whereas, for STOP trials, the TMS pulses occurred 150 ms after the stop signal. The timings of the TMS pulses were decided based on electroencephalography (EEG) studies showing event-related changes in these time ranges during stop signal tasks. This task was studied in 3 blocks at two study sites (n=38) and we recorded behavioral performance and event-related motor-evoked potentials (MEP). Regression modelling was used to analyze MEP amplitudes using age as a covariate with multiple independent variables (sex, study site, block, TMS pulse condition [single- vs. paired-pulse], trial condition [GO, successful STOP, failed STOP]). The analysis showed that TMS pulse condition (p<0.0001) and its interaction with trial condition (p=0.009) were significant. Future applications for this online S-H/TMS paradigm include the addition of simultaneous EEG acquisition to measure TMS-evoked EEG potentials. A

  1. Mechanical effects of repetitive transcranial magnetic stimulation of upper airway muscles in awake obstructive sleep apnoea subjects.

    Science.gov (United States)

    Rousseau, Eric; Gakwaya, Simon; Melo-Silva, César Augusto; Sériès, Frédéric

    2015-04-20

    What is the central question of this study? Can repetitive transcranial magnetic stimulation (rTMS) of the genioglossus enhance the beneficial effects observed with transcranial magnetic stimulation single twitches on upper airway mechanical properties? What is the main finding and its importance? We found that both inspiratory and expiratory rTMS protocols induce a different activation pattern of upper airway muscles, with evidence for an increase in genioglossus corticomotor excitability in response to rTMS. This is of major importance because it might open the door for rTMS protocols with the goal of increasing corticomotor excitability and, thus, possibly increasing the tonic genioglossus activity, which is known to be diminished during sleep in subjects with sleep apnoea. Stimulation of upper airway (UA) muscles during sleep by isolated transcranial magnetic stimulation (TMS) twitch can improve airflow dynamics without arousal, but the effect of repetitive TMS (rTMS) on UA dynamics is unknown. Phrenic nerve magnetic stimulation (PNMS) can be used to produce painless experimental twitch-induced flow limitation during wakefulness. The aim of this study was to quantify the effects of rTMS applied during wakefulness on UA mechanical properties using PNMS in subjects with obstructive sleep apnoea (OSA). Phrenic nerve magnetic stimulation was applied to 10 subjects, with and without simultaneous rTMS, during inspiration and expiration. Flow-limitation characteristics and UA obstruction level were determined [maximal (V̇I,max)and minimal inspiratory airflow (V̇I,min),V̇I,max-V̇I,min flow drop (ΔV̇I),oropharyngeal (POro,peak ) and velopharyngeal peak pressures, oropharyngeal k1 /k2 ratios with k1 and k2 determined by the polynomial regression model between instantaneous flow and pharyngeal pressure and UA resistance]. Both genioglossus and diaphragm root mean squares and motor-evoked potential amplitudes (geniolossus, GGAmp ) and latencies were computed. A flow

  2. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa

    2010-01-01

    Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals, we applied 30 min of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate...... the involvement of left rPMd and SMG in the rapid adjustment of actions guided by visuospatial cues. After rTMS, subjects underwent functional magnetic resonance imaging while making spatially congruent button presses with the right or left index finger in response to a left- or right-sided target. Subjects were...... responses in invalidly cued trials. After real rTMS, task-related activity of the stimulated left rPMd showed increased task-related coupling with activity in ipsilateral SMG and the adjacent anterior intraparietal area (AIP). Individuals who showed a stronger increase in left-hemispheric premotor...

  3. Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Poststroke Patients with Upper Limb Hemiparesis: Preliminary Study of a 15-Day Protocol

    Science.gov (United States)

    Kakuda, Wataru; Abo, Masahiro; Kobayashi, Kazushige; Momosaki, Ryo; Yokoi, Aki; Fukuda, Akiko; Ishikawa, Atsushi; Ito, Hiroshi; Tominaga, Ayumi

    2010-01-01

    The purpose of the study was to determine the safety and feasibility of a 15-day protocol of low-frequency repetitive transcranial magnetic stimulation (rTMS) combined with intensive occupational therapy (OT) on motor function and spasticity in hemiparetic upper limbs in poststroke patients. Fifteen poststroke patients (age at study entry 55 [plus…

  4. High frequency repetitive transcranial magnetic over the medial cerebellum induces a shift in the prefrontal electroencephalography gamma spectrum: a pilot study in humans

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Honk, E.J. van; d'Alfonso, A.A.L.; Peper, J.S.; Panksepp, J.

    2003-01-01

    In the present study the anatomical projections from the medial cerebellum to the prefrontal cortex (PFC) were investigated in healthy human subjects, using high frequency repetitive transcranial magnetic (rTMS) stimulation and electro-encephalography (EEG). Medial cerebellar rTMS, compared to

  5. Preliminary Evidence of the Effects of High-frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Swallowing Functions in Post-Stroke Individuals with Chronic Dysphagia

    Science.gov (United States)

    Cheng, Ivy K. Y.; Chan, Karen M. K.; Wong, C. S.; Cheung, Raymond T. F.

    2015-01-01

    Background: There is growing evidence of potential benefits of repetitive transcranial magnetic stimulation (rTMS) in the rehabilitation of dysphagia. However, the site and frequency of stimulation for optimal effects are not clear. Aims: The aim of this pilot study is to investigate the short-term effects of high-frequency 5 Hz rTMS applied to…

  6. Deep Transcranial Magnetic Stimulation: A Promising Drug-Free Treatment Modality in the Treatment of Chronic Low Back Pain.

    Science.gov (United States)

    Yates, Erin; Balu, Ganesh

    2016-03-01

    Deep Transcranial Magnetic Stimulation (dTMS) is the next generation of technology used to treat Major Depressive Disorder (MDD). dTMS has been proven to be a safe and effective treatment modality for MDD and may have secondary benefits in patients with chronic low back pain by reducing pain related morbidity. We are presenting two case studies with MDD and chronic low back pain to demonstrate the effectiveness of both the antidepressant and analgesic effects of dTMS. Transcranial Magnetic Stimulation (rTMS) utilizes MRI-strength magnetic pulses outside the cranium to stimulate the brain to a depth of approximately 1 cm. The technique was approved by the US Food and Drug Administration (FDA) for the treatment of Major Depressive Disorder (MDD) in 2008. In 2013 the Brainsway Deep Transcranial Magnetic Stimulation (dTMS) device, which has the potential for cranial penetration up to 5 cm received FDA clearance for pharmacotherapy and psychotherapy resistant MDD. The mechanism of action of dTMS in MDD is not completely understood. However, its clinical efficacy is proven.' The effect of dTMS on the brain has been studied since 1985 in clinical trials and has been demonstrated as an effective treatment modality for refractory depressive symptoms. The mechanism of action of dTMS is thought to be mediated by increased connectivity between the dorsolateral prefrontal cortex (DLPFC) and the thalamus and reduced subgenual cingulate to caudate connectivity. These brain areas are believed to be responsible for modulating mood. Chronic pain is often accompanied by MDD. Specifically, chronic low back pain is highly prevalent and accompanied by significant disability.2 Low back pain is defined as chronic when the pain is continuous for more than three months. The current chronic pain treatment algorithm includes judicious use of non pharmacological interventions like physical therapy, chiropractic adjustments, therapeutic massage, or acupuncture combined with pharmacological

  7. Repetitive transcranial magnetic stimulation over the supplementary motor area modifies breathing patternin response to inspiratory loading in normal humans

    Directory of Open Access Journals (Sweden)

    Marie-Cécile eNierat

    2015-09-01

    Full Text Available In awake humans, breathing depends on automatic brainstem pattern generators. It is also heavily influenced by cortical networks. For example, functional magnetic resonance imaging and electroencephalographic data show that the supplementary motor area becomes active when breathing is made difficult by inspiratory mechanical loads like resistances or threshold valves This is associated with perceived respiratory discomfort. We hypothesized that manipulating the excitability of the supplementary motor area with repetitive transcranial magnetic stimulation would modify the breathing pattern response to an experimental inspiratory load possibly respiratory discomfort. Seven subjects (3 men, age 25±4 were studied. Breathing pattern and respiratory discomfort during inspiratory loading were described before and after conditioning the supplementary motor area with repetitive stimulation, using an excitatory paradigm (5Hz stimulation, an inhibitory paradigm, or sham stimulation. No significant change in breathing pattern during loading was observed after sham conditioning. Excitatory conditioning shortened inspiratory time (p=0.001, decreased tidal volume (p=0.016, and decreased ventilation (p=0.003, as corroborated by an increased end-tidal expired carbon dioxide (p=0.013. Inhibitory conditioning did not affect ventilation, but lengthened expiratory time (p=0.031. Respiratory discomfort was mild under baseline conditions, and unchanged after conditioning of the supplementary motor area. This is the first study to show that repetitive transcranial magnetic stimulation conditioning of the cerebral cortex can alter breathing pattern. A 5 Hz conditioning protocol, known to enhance corticophrenic excitability, can reduce the amount of hyperventilation induced by inspiratory threshold loading. Further studies are needed to determine whether and under what circumstances rTMS can have an effect on dyspnoea.

  8. Contralesional repetitive transcranial magnetic stimulation for chronic hemiparesis in subcortical paediatric stroke: a randomised trial.

    Science.gov (United States)

    Kirton, Adam; Chen, Robert; Friefeld, Sharon; Gunraj, Carolyn; Pontigon, Anne-Marie; Deveber, Gabrielle

    2008-06-01

    Arterial ischaemic stroke (AIS) can cause disabling hemiparesis in children. We aimed to test whether contralesional, inhibitory repetitive transcranial magnetic stimulation (rTMS) could affect interhemispheric inhibition to improve hand function in chronic subcortical paediatric AIS. Patients were eligible for this parallel, randomised trial if they were in the SickKids Children's Stroke Program and had subcortical AIS more than 2 years previously, had transcallosal sparing, were more than 7 years of age, had hand motor impairment, had no seizures or dyskinesia, and were taking no drugs that alter cortical excitability. Patients were paired for age and weakness and were randomised within each pair to sham treatment or inhibitory, low-frequency rTMS over contralesional motor cortex (20 min, 1200 stimuli) once per day for 8 days. An occupational therapist did standardised tests of hand function at days 1 (baseline), 5, 10, and 17 (1 week post-treatment), and the primary outcomes were changes in grip strength and the Melbourne assessment of upper extremity function (MAUEF) between baseline and day 10. Patients, parents, and occupational therapists were blinded to treatment allocation. Analysis was per protocol. Ten patients with paediatric stroke were enrolled (median age 13.25 [IQR 10.08-16.78] years, mean time post-stroke 6.33 [SD 3.56] years): four with mild weakness, two with moderate weakness, and four with severe weakness. A repeated-measures ANOVA showed a significant interaction between time and the effect of treatment on grip strength (p=0.03). At day 10, grip strength was 2.28 (SD 1.01) kg greater than baseline in the rTMS group and 2.92 (1.20) kg less than baseline in the sham group (p=0.009). Benefits in mean grip strength persisted at day 17 (2.63 [0.56] kg greater than baseline with rTMS and 1.00 [0.70] kg less than baseline with sham treatment; p=0.01). Day 10 MAUEF score improved by more in the rTMS group than in the sham group (7.25 [3.8] vs 0.79 [1

  9. Single-pulse electrons from a linear accelerator

    International Nuclear Information System (INIS)

    Antoku, Shigetoshi; Sunayashiki, Tadashi; Takeoka, Seiji; Kato, Kazushi

    1976-01-01

    The electronic circuits of a 35 MeV linear accelerator at Hiroshima University were modified to produce single-pulse electrons. Single-pulse electrons were obtained by synchronizing one of eight pulses from an electron gun modulator, 120 pps, to one of the micro-waves from a klystron, 15 pps. After single-pulse electrons were discharged, a signal was relayed to a stop-gate circuit from a binary scaler which was connected to the gun modulator. Although reproducibility of single-pulse electrons and stability of electron output per pulse were not completely satisfactory, it was possible to use for radiobiological studies. Biological effects of single-pulse electrons (energy: 25 MeV, dose rate: 10 10 rad/min) on cultured mammalian cells and on mice were nearly equal to those of multi-pulse electrons (25 MeV, 10 7 rad/min) and Co-60 γ-rays (dose rate: 100 rad/min). (auth.)

  10. Assessment of Event-Related EEG Power After Single-Pulse TMS in Unresponsive Wakefulness Syndrome and Minimally Conscious State Patients.

    Science.gov (United States)

    Formaggio, Emanuela; Cavinato, Marianna; Storti, Silvia Francesca; Tonin, Paolo; Piccione, Francesco; Manganotti, Paolo

    2016-03-01

    In patients without a behavioral response, non-invasive techniques and new methods of data analysis can complement existing diagnostic tools by providing a method for detecting covert signs of residual cognitive function and awareness. The aim of this study was to investigate the brain oscillatory activities synchronized by single-pulse transcranial magnetic stimulation (TMS) delivered over the primary motor area in the time-frequency domain in patients with the unresponsive wakefulness syndrome or in a minimally conscious state as compared to healthy controls. A time-frequency analysis based on the wavelet transform was used to characterize rapid modifications of oscillatory EEG rhythms induced by TMS in patients as compared to healthy controls. The pattern of EEG changes in the patients differed from that of healthy controls. In the controls there was an early synchronization of slow waves immediately followed by a desynchronization of alpha and beta frequency bands over the frontal and centro-parietal electrodes, whereas an opposite early synchronization, particularly over motor areas for alpha and beta and over the frontal and parietal electrodes for beta power, was seen in the patients. In addition, no relevant modification in slow rhythms (delta and theta) after TMS was noted in patients. The clinical impact of these findings could be relevant in neurorehabilitation settings for increasing the awareness of these patients and defining new treatment procedures.

  11. A preliminary transcranial magnetic stimulation study of cortical inhibition and excitability in high-functioning autism and Asperger disorder.

    Science.gov (United States)

    Enticott, Peter G; Rinehart, Nicole J; Tonge, Bruce J; Bradshaw, John L; Fitzgerald, Paul B

    2010-08-01

    Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Participants were diagnosed by experienced clinicians strictly according to DSM-IV criteria. Participants with HFA (nine males, two females; mean age 16y 8mo, SD 4y 5mo) or Asperger disorder (11 males, three females; mean age 19y 1mo, SD 4y 2mo) and neurotypical participants (eight males, three females; mean age 19y 0mo, SD 3y 1mo) were administered a paired-pulse TMS paradigm intended to assess motor cortical inhibition and excitability. Responses to TMS were recorded by electromyography. Cortical inhibition was significantly reduced in the HFA group compared with both the Asperger disorder (pAsperger disorder based on GABAergic function.

  12. Failure of activation of spinal motoneurones after muscle fatigue in healthy subjects studied by transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Andersen, Birgit; Westlund, Barbro; Krarup, Christian

    2003-01-01

    . This points to increased probability of repetitive spinal MN activation during fatigue even if some MNs in the pool failed to discharge. Silent period duration following cortical stimulation lengthened by an average of 55 ms after the contraction and recovered within a time course similar to that of the TST...... to estimate the proportion of motor units activated by a transcranial magnetic stimulus. Following a sustained contraction of the abductor digiti minimi muscle at 50 % maximal force maintained to exhaustion there was an immediate reduction of the TST response from > 95 % to about 60 %. This effect recovered...... response depression. Overall, the results suggest that the outflow from the motor cortex could become insufficient to drive all spinal MNs to discharge when the muscle is fatigued and that complex interactions between failure of activation and compensatory mechanisms to maintain motor unit activation occur...

  13. Transcranial magnetic stimulation at the interface with other techniques: a powerful tool for studying the human cortex.

    Science.gov (United States)

    Ziemann, Ulf

    2011-08-01

    Transcranial magnetic stimulation (TMS) has developed into a very powerful tool in the hands of basic and clinical neuroscientists alike to study function and dysfunction of the human brain noninvasively and painlessly. However, as a stand-alone technique, the potential of TMS to gain knowledge is relatively limited. This potential can be strongly enhanced by combining TMS with simultaneous measurements in other electrophysiological (EEG) or imaging modalities (PET, fMRI, NIRS, MRS) or by combining TMS with exposure to neuroactive drugs (pharmaco-TMS). This review provides an up-to-date synopsis of these combined approaches and highlights important examples that have advanced our understanding of how TMS interacts with neuronal networks in the human brain.

  14. Association of intracortical inhibition with social cognition deficits in schizophrenia: Findings from a transcranial magnetic stimulation study.

    Science.gov (United States)

    Mehta, Urvakhsh Meherwan; Thirthalli, Jagadisha; Basavaraju, Rakshathi; Gangadhar, Bangalore N

    2014-09-01

    Abnormal cortical-inhibition has been hypothesized to underlie social-cognition deficits in schizophrenia. Studies using transcranial magnetic stimulation (TMS) as a neurophysiological probe have demonstrated cortical-inhibition deficits in this group. We compared TMS-measured short- and long-interval intracortical-inhibition (SICI & LICI) in antipsychotic-naïve (n=33) and medicated (n=21) schizophrenia patients and in healthy comparison subjects (n=45). We also studied the association between cortical-inhibition and social-cognition deficits in the patients. Antipsychotic-naïve patients had significant deficits in SICI (i.e., less inhibitory response). In this group, SICI had significant inverse correlations with emotion processing and a global social-cognition score. Impaired intracortical-inhibition may thus contribute to social-cognition deficits in schizophrenia. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

    Science.gov (United States)

    Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.

    2013-01-01

    Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding. There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self) and allocentric (i.e., other) viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity), there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation. PMID:24137125

  16. A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system

    Directory of Open Access Journals (Sweden)

    Jed Donald Burgess

    2013-10-01

    Full Text Available Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric. Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation (TMS experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self and allocentric (i.e., other viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity, there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation.

  17. The effects of high-frequency transcranial magnetic stimulation combined with transcutaneous electrical stimulation in a severe stroke patient.

    Science.gov (United States)

    Koyama, Soichiro; Tanabe, Shigeo; Takeda, Kazuya; Warashina, Hiroaki; Sakurai, Hiroaki; Kanada, Yoshikiyo; Okumura, Ryuji; Shinoda, Jun; Nagata, Junji; Kanno, Tetsuo

    2012-10-12

    The case report describes the effects of 5 Hz repetitive transcranial magnetic stimulation (rTMS) combined with transcutaneous electrical stimulation (TES) in a patient with severe stroke. The patient was a 69-year-old male who was affected by a left middle cerebral artery infarction. The patient had no movement in his right hand. To assess the effects, cerebral blood flow and motor function were measured before and after treatment. This treatment delivered rTMS over the affected M1 with TES at the paretic wrist extensor muscles for 10 days. The regional cerebral blood flow (rCBF) in the entire brain was measured by positronemission tomography. To evaluate the motor function, the Fugl-Meyer assessment (FMA) was used. After treatment, the rCBF was increased (except for the stimulated region), and the FMA score was slightly improved. These results suggest the potential therapeutic use of rTMS combined with TES for recovery in severe stroke.

  18. Effects of Repetitive Transcranial Magnetic Stimulation on Behavioral Recovery during Early Stage of Traumatic Brain Injury in Rats.

    Science.gov (United States)

    Yoon, Kyung Jae; Lee, Yong-Taek; Chung, Pil-Wook; Lee, Yun Kyung; Kim, Dae Yul; Chun, Min Ho

    2015-10-01

    Repetitive transcranial magnetic stimulation (rTMS) is a promising technique that modulates neural networks. However, there were few studies evaluating the effects of rTMS in traumatic brain injury (TBI). Herein, we assessed the effectiveness of rTMS on behavioral recovery and metabolic changes using brain magnetic resonance spectroscopy (MRS) in a rat model of TBI. We also evaluated the safety of rTMS by measuring brain swelling with brain magnetic resonance imaging (MRI). Twenty male Sprague-Dawley rats underwent lateral fluid percussion and were randomly assigned to the sham (n=10) or the rTMS (n=10) group. rTMS was applied on the fourth day after TBI and consisted of 10 daily sessions for 2 weeks with 10 Hz frequency (total pulses=3,000). Although the rTMS group showed an anti-apoptotic effect around the peri-lesional area, functional improvements were not significantly different between the two groups. Additionally, rTMS did not modulate brain metabolites in MRS, nor was there any change of brain lesion or edema after magnetic stimulation. These data suggest that rTMS did not have beneficial effects on motor recovery during early stages of TBI, although an anti-apoptosis was observed in the peri-lesional area.

  19. Effects of repetitive transcranial magnetic stimulation on motor functions in patients with stroke: a meta-analysis.

    Science.gov (United States)

    Hsu, Wan-Yu; Cheng, Chia-Hsiung; Liao, Kwong-Kum; Lee, I-Hui; Lin, Yung-Yang

    2012-07-01

    The purpose of this study was to perform a meta-analysis of studies that investigated the effects of repetitive transcranial magnetic stimulation (rTMS) on upper limb motor function in patients with stroke. We searched for randomized controlled trials published between January 1990 and October 2011 in PubMed, Medline, Cochrane, and CINAHL using the following key words: stroke, cerebrovascular accident, and repetitive transcranial magnetic stimulation. The mean effect size and a 95% CI were estimated for the motor outcome and motor threshold using fixed and random effect models. Eighteen of the 34 candidate articles were included in this analysis. The selected studies involved a total of 392 patients. A significant effect size of 0.55 was found for motor outcome (95% CI, 0.37-0.72). Further subgroup analyses demonstrated more prominent effects for subcortical stroke (mean effect size, 0.73; 95% CI, 0.44-1.02) or studies applying low-frequency rTMS (mean effect size, 0.69; 95% CI, 0.42-0.95). Only 4 patients of the 18 articles included in this analysis reported adverse effects from rTMS. rTMS has a positive effect on motor recovery in patients with stroke, especially for those with subcortical stroke. Low-frequency rTMS over the unaffected hemisphere may be more beneficial than high-frequency rTMS over the affected hemisphere. Recent limited data suggest that intermittent theta-burst stimulation over the affected hemisphere might be a useful intervention. Further well-designed studies in a larger population are required to better elucidate the differential roles of various rTMS protocols in stroke treatment.

  20. Correlation between severity of clinical signs and transcranial magnetic motor evoked potentials in dogs with intervertebral disc herniation.

    Science.gov (United States)

    Amendt, H-L; Siedenburg, J S; Steffensen, N; Kordass, U; Rohn, K; Tipold, A; Stein, V M

    2017-03-01

    Transcranial magnetic motor evoked potentials (TMMEPs) can assess the functional integrity of the spinal cord descending motor pathways. In intervertebral disc herniation (IVDH), these pathways are compromised to varying degrees reflected by the severity of neurological deficits. The hypotheses of this study were as follows: (1) TMMEPs differ in dogs with IVDH and healthy control dogs; (2) TMMEPs reflect different severities of neurological signs; and (3) TMMEPs can document functional motor improvement and therefore monitor recovery of function. TMMEPs were recorded in 50 dogs with thoracolumbar IVDH. Clinical signs ranged from spinal hyperesthesia to non-ambulatory paraparesis in 19 dogs and paraplegia with/without deep pain sensation in 31 dogs. In these 31 paraplegic dogs, transcranial magnetic stimulation (TMS) was repeated during follow-up examinations. Ten healthy Beagle dogs served as controls. There was a significant increase in onset latency and decrease in peak-to-peak amplitude in the pelvic limb TMMEPs of dogs with spinal hyperesthesia to severe paraparesis compared to control dogs. Waveforms in dogs with IVDH were predominantly polyphasic in contrast to the biphasic waveforms of the control dogs. TMMEPs could not be generated in the pelvic limbs of paraplegic dogs. However, TMMEPs with markedly increased onset latencies and decreased peak-to-peak amplitudes reappeared in the pelvic limbs of dogs that were paraplegic before surgery and showed functional motor improvement during follow-up. The severity of neurological deficits was reflected by TMMEP findings, which could be used to document functional motor recovery in IVDH. TMS could therefore be used as an ancillary test to monitor response to therapy in dogs during rehabilitation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Measuring and manipulating brain connectivity with resting state functional connectivity magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS).

    Science.gov (United States)

    Fox, Michael D; Halko, Mark A; Eldaief, Mark C; Pascual-Leone, Alvaro

    2012-10-01

    Both resting state functional magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS) are increasingly popular techniques that can be used to non-invasively measure brain connectivity in human subjects. TMS shows additional promise as a method to manipulate brain connectivity. In this review we discuss how these two complimentary tools can be combined to optimally study brain connectivity and manipulate distributed brain networks. Important clinical applications include using resting state fcMRI to guide target selection for TMS and using TMS to modulate pathological network interactions identified with resting state fcMRI. The combination of TMS and resting state fcMRI has the potential to accelerate the translation of both techniques into the clinical realm and promises a new approach to the diagnosis and treatment of neurological and psychiatric diseases that demonstrate network pathology. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Electromagnetic Field Modeling of Transcranial Electric and Magnetic Stimulation: Targeting, Individualization, and Safety of Convulsive and Subconvulsive Applications

    Science.gov (United States)

    Deng, Zhi-De

    The proliferation of noninvasive transcranial electric and magnetic brain stimulation techniques and applications in recent years has led to important insights into brain function and pathophysiology of brain-based disorders. Transcranial electric and magnetic stimulation encompasses a wide spectrum of methods that have developed into therapeutic interventions for a variety of neurological and psychiatric disorders. Although these methods are at different stages of development, the physical principle underlying these techniques is the similar. Namely, an electromagnetic field is induced in the brain either via current injection through scalp electrodes or via electromagnetic induction. The induced electric field modulates the neuronal transmembrane potentials and, thereby, neuronal excitability or activity. Therefore, knowledge of the induced electric field distribution is key in the design and interpretation of basic research and clinical studies. This work aims to delineate the fundamental physical limitations, tradeoffs, and technological feasibility constraints associated with transcranial electric and magnetic stimulation, in order to inform the development of technologies that deliver safer, and more spatially, temporally, and patient specific stimulation. Part I of this dissertation expounds on the issue of spatial targeting of the electric field. Contrasting electroconvulsive therapy (ECT) and magnetic seizure therapy (MST) configurations that differ markedly in efficacy, side effects, and seizure induction efficiency could advance our understanding of the principles linking treatment parameters and therapeutic outcome and could provide a means of testing hypotheses of the mechanisms of therapeutic action. Using the finite element method, we systematically compare the electric field characteristics of existing forms of ECT and MST. We introduce a method of incorporating a modality-specific neural activation threshold in the electric field models that can

  3. Test-retest assessment of cortical activation induced by repetitive transcranial magnetic stimulation with brain atlas-guided optical topography

    Science.gov (United States)

    Tian, Fenghua; Kozel, F. Andrew; Yennu, Amarnath; Croarkin, Paul E.; McClintock, Shawn M.; Mapes, Kimberly S.; Husain, Mustafa M.; Liu, Hanli

    2012-11-01

    Repetitive transcranial magnetic stimulation (rTMS) is a technology that stimulates neurons with rapidly changing magnetic pulses with demonstrated therapeutic applications for various neuropsychiatric disorders. Functional near-infrared spectroscopy (fNIRS) is a suitable tool to assess rTMS-evoked brain responses without interference from the magnetic or electric fields generated by the TMS coil. We have previously reported a channel-wise study of combined rTMS/fNIRS on the motor and prefrontal cortices, showing a robust decrease of oxygenated hemoglobin concentration (Δ[HbO2]) at the sites of 1-Hz rTMS and the contralateral brain regions. However, the reliability of this putative clinical tool is unknown. In this study, we develop a rapid optical topography approach to spatially characterize the rTMS-evoked hemodynamic responses on a standard brain atlas. A hemispherical approximation of the brain is employed to convert the three-dimensional topography on the complex brain surface to a two-dimensional topography in the spherical coordinate system. The test-retest reliability of the combined rTMS/fNIRS is assessed using repeated measurements performed two to three days apart. The results demonstrate that the Δ[HbO2] amplitudes have moderate-to-high reliability at the group level; and the spatial patterns of the topographic images have high reproducibility in size and a moderate degree of overlap at the individual level.

  4. Lateralized hippocampal volume increase following high-frequency left prefrontal repetitive transcranial magnetic stimulation in patients with major depression.

    Science.gov (United States)

    Hayasaka, Shunsuke; Nakamura, Motoaki; Noda, Yoshihiro; Izuno, Takuji; Saeki, Takashi; Iwanari, Hideo; Hirayasu, Yoshio

    2017-11-01

    Repetitive transcranial magnetic stimulation (rTMS) has been applied as a treatment for patients with treatment-resistant depression in recent years, and a large body of evidence has demonstrated its therapeutic efficacy through stimulating neuronal plasticity. The aim of this study was to investigate structural alterations in the hippocampus (HIPP) and amygdala (AM) following conventional rTMS in patients with depression. Twenty-eight patients with depression underwent 10 daily 20-Hz left prefrontal rTMS over 2 weeks. The left dorsolateral prefrontal cortex (DLPFC) was identified using magnetic resonance imaging-guided neuronavigation prior to stimulation. Magnetic resonance imaging scans were obtained at baseline and after the completion of rTMS sessions. The therapeutic effects of rTMS were evaluated with the 17-item Hamilton Depression Rating Scale (HAM-D 17 ), and the volumes of the HIPP and AM were measured by a manual tracing method. Statistical analyses revealed a significant volume increase in the left HIPP (+3.4%) after rTMS but no significant volume change in the AM. No correlation was found between the left HIPP volume increase and clinical improvement, as measured by the HAM-D 17 . The present study demonstrated that conventional left prefrontal rTMS increases the HIPP volume in the stimulated side, indicating a remote neuroplastic effect through the cingulum bundle. © 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.

  5. Combining non-invasive transcranial brain stimulation with neuroimaging and electrophysiology: Current approaches and future perspectives

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Karabanov, Anke; Hartwigsen, Gesa

    2016-01-01

    Non-invasive transcranial brain stimulation (NTBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial current stimulation (TCS) are important tools in human systems and cognitive neuroscience because they are able to reveal the relevance of certain brain structures...

  6. Investigation of shape, position, and permeability of shielding material in quadruple butterfly coil for focused transcranial magnetic stimulation

    Science.gov (United States)

    Rastogi, Priyam; Zhang, Bowen; Tang, Yalun; Lee, Erik G.; Hadimani, Ravi L.; Jiles, David C.

    2018-05-01

    Transcranial magnetic stimulation has been gaining popularity in the therapy for several neurological disorders. A time-varying magnetic field is used to generate electric field in the brain. As the development of TMS methods takes place, emphasis on the coil design increases in order to improve focal stimulation. Ideally reduction of stimulation of neighboring regions of the target area is desired. This study, focused on the improvement of the focality of the Quadruple Butterfly Coil (QBC) with supplemental use of different passive shields. Parameters such as shape, position and permeability of the shields have been explored to improve the focus of stimulation. Results have been obtained with the help of computer modelling of a MRI derived heterogeneous head model over the vertex position and the dorsolateral prefrontal cortex position using a finite element tool. Variables such as maximum electric field induced on the grey matter and scalp, volume and area of stimulation above half of the maximum value of electric field on the grey matter, and ratio of the maximum electric field in the brain versus the scalp have been investigated.

  7. 3D modeling of the total electric field induced by transcranial magnetic stimulation using the boundary element method

    Science.gov (United States)

    Salinas, F. S.; Lancaster, J. L.; Fox, P. T.

    2009-06-01

    Transcranial magnetic stimulation (TMS) delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians with a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this paper, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistically shaped head model was used to assess the effect of multiple surfaces on the total E-field. Secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes typically range from 20% to 35% of the primary E-field's magnitude. The direction of the secondary E-field was generally in opposition to the primary E-field; however, for some locations, this was not the case (i.e. going from high to low conductivity tissues). These findings show that realistically shaped head geometries are important for accurate modeling of the total E-field.

  8. Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations From a TMS Coil.

    Science.gov (United States)

    Makarov, Sergey N; Yanamadala, Janakinadh; Piazza, Matthew W; Helderman, Alex M; Thang, Niang S; Burnham, Edward H; Pascual-Leone, Alvaro

    2016-09-01

    Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of this study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup. We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100 000 observation points, and two distinct pulse rise times; thus, providing a representative number of different datasets for comparison, while also using other numerical data. Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average. The simple analytical model tested in this study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body. At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women.

  9. An efficient 3-D eddy-current solver using an independent impedance method for transcranial magnetic stimulation.

    Science.gov (United States)

    De Geeter, Nele; Crevecoeur, Guillaume; Dupre, Luc

    2011-02-01

    In many important bioelectromagnetic problem settings, eddy-current simulations are required. Examples are the reduction of eddy-current artifacts in magnetic resonance imaging and techniques, whereby the eddy currents interact with the biological system, like the alteration of the neurophysiology due to transcranial magnetic stimulation (TMS). TMS has become an important tool for the diagnosis and treatment of neurological diseases and psychiatric disorders. A widely applied method for simulating the eddy currents is the impedance method (IM). However, this method has to contend with an ill conditioned problem and consequently a long convergence time. When dealing with optimal design problems and sensitivity control, the convergence rate becomes even more crucial since the eddy-current solver needs to be evaluated in an iterative loop. Therefore, we introduce an independent IM (IIM), which improves the conditionality and speeds up the numerical convergence. This paper shows how IIM is based on IM and what are the advantages. Moreover, the method is applied to the efficient simulation of TMS. The proposed IIM achieves superior convergence properties with high time efficiency, compared to the traditional IM and is therefore a useful tool for accurate and fast TMS simulations.

  10. Movement and afferent representations in human motor areas: a simultaneous neuroimaging and transcranial magnetic/peripheral nerve-stimulation study

    Directory of Open Access Journals (Sweden)

    Hitoshi eShitara

    2013-09-01

    Full Text Available Neuroimaging combined with transcranial magnetic stimulation (TMS to primary motor cortex (M1 is an emerging technique that can examine motor-system functionality through evoked activity. However, because sensory afferents from twitching muscles are widely represented in motor areas the amount of evoked activity directly resulting from TMS remains unclear. We delivered suprathreshold TMS to left M1 or electrically stimulated the right median nerve (MNS in 18 healthy volunteers while simultaneously conducting functional magnetic resonance imaging and monitoring with electromyography (EMG. We examined in detail the localization of TMS-, muscle afferent- and superficial afferent-induced activity in M1 subdivisions. Muscle afferent- and TMS-evoked activity occurred mainly in rostral M1, while superficial afferents generated a slightly different activation distribution. In 12 participants who yielded quantifiable EMG, differences in brain activity ascribed to differences in movement-size were adjusted using integrated information from the EMGs. Sensory components only explained 10-20% of the suprathreshold TMS-induced activity, indicating that locally and remotely evoked activity in motor areas mostly resulted from the recruitment of neural and synaptic activity. The present study appears to justify the use of fMRI combined with suprathreshold TMS to M1 for evoked motor network imaging.

  11. Magnetic resonance imaging/angiography and transcranial Doppler velocities in sickle cell anemia: results from the SWiTCH trial.

    Science.gov (United States)

    Helton, Kathleen J; Adams, Robert J; Kesler, Karen L; Lockhart, Alex; Aygun, Banu; Driscoll, Catherine; Heeney, Matthew M; Jackson, Sherron M; Krishnamurti, Lakshmanan; Miller, Scott T; Sarnaik, Sharada A; Schultz, William H; Ware, Russell E

    2014-08-07

    The Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) trial compared standard (transfusions/chelation) to alternative (hydroxyurea/phlebotomy) treatment to prevent recurrent stroke and manage iron overload in children chronically transfused over 7 years before enrollment. Standardized brain magnetic resonance imaging/magnetic resonance angiography (MRA) and transcranial Doppler (TCD) exams were performed at entry and exit, with a central blinded review. A novel MRA vasculopathy grading scale demonstrated frequent severe baseline left/right vessel stenosis (53%/41% ≥Grade 4); 31% had no vessel stenosis on either side. Baseline parenchymal injury was prevalent (85%/79% subcortical, 53%/37% cortical, 50%/35% subcortical and cortical). Most children had low or uninterpretable baseline middle cerebral artery TCD velocities, which were associated with worse stenoses (incidence risk ratio [IRR] = 5.1, P ≤ .0001 and IRR = 4.1, P severe parenchymal and vascular abnormalities in children with SCA and stroke and support concerns about chronic transfusions lacking effectiveness for preventing progressive cerebrovascular injury. The novel SWiTCH vasculopathy grading scale warrants validation testing and consideration for use in future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT00122980. © 2014 by The American Society of Hematology.

  12. Diffusion Tensor Imaging Evaluation of Neural Network Development in Patients Undergoing Therapeutic Repetitive Transcranial Magnetic Stimulation following Stroke

    Directory of Open Access Journals (Sweden)

    Naoki Yamada

    2018-01-01

    Full Text Available We aimed to investigate plastic changes in cerebral white matter structures using diffusion tensor imaging following a 15-day stroke rehabilitation program. We compared the detection of cerebral plasticity between generalized fractional anisotropy (GFA, a novel tool for investigating white matter structures, and fractional anisotropy (FA. Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS of 2400 pulses applied to the nonlesional hemisphere and 240 min intensive occupation therapy (OT daily over 15 days. Motor function was evaluated using the Fugl-Meyer assessment (FMA and Wolf Motor Function Test (WMFT. Patients underwent diffusion tensor magnetic resonance imaging (MRI on admission and discharge, from which bilateral FA and GFA values in Brodmann area (BA 4 and BA6 were calculated. Motor function improved following treatment (p<0.001. Treatment increased GFA values for both the lesioned and nonlesioned BA4 (p<0.05, p<0.001, resp.. Changes in GFA value for BA4 of the lesioned hemisphere were significantly inversely correlated with changes in WMFT scores (R2=0.363, p<0.05. Our findings indicate that the GFA may have a potentially more useful ability than FA to detect changes in white matter structures in areas of fiber intersection for any such future investigations.

  13. The Relationship Between Brain Oscillatory Activity and Therapeutic Effectiveness of Transcranial Magnetic Stimulation in the Treatment of Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Andrew Francis Leuchter

    2013-02-01

    Full Text Available Major Depressive Disorder (MDD is marked by disturbances in brain functional connectivity. This connectivity is modulated by rhythmic oscillations of brain electrical activity, which enable coordinated functions across brain regions. Oscillatory activity plays a central role in regulating thinking and memory, mood, cerebral blood flow, and neurotransmitter levels, and restoration of normal oscillatory patterns is associated with effective treatment of MDD. Repetitive Transcranial Magnetic Stimulation (rTMS is a robust treatment for MDD, but the mechanism of action (MOA of its benefits for mood disorders remains incompletely understood. Benefits of rTMS have been tied to enhanced neuroplasticity in specific brain pathways. We summarize here the evidence that rTMS entrains and resets thalamocortical oscillators, normalizes regulation and facilitates reemergence of intrinsic cerebral rhythms, and through this mechanism restores normal brain function. This entrainment and resetting may be a critical step in engendering neuroplastic changes and the antidepressant effects of rTMS. It may be possible to modify the method of rTMS administration to enhance this mechanism of action and achieve better antidepressant effectiveness. We propose that rTMS can be administered: 1 synchronized to a patient’s individual alpha rhythm (IAF, or synchronized rTMS (sTMS; 2 as a low magnetic field strength sinusoidal wave form; and, 3 broadly to multiple brain areas simultaneously. We present here the theory and evidence indicating that these modifications could enhance the therapeutic effectiveness of rTMS for the treatment of MDD.

  14. Transcranial magnetic stimulation but not MRI predicts long-term clinical status in cervical spondylosis: a case series.

    Science.gov (United States)

    Deftereos, S N; Kechagias, E; Ioakeimidou, C; Georgonikou, D

    2015-03-01

    Case series. To compare transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI) findings between patients who underwent surgery for cervical spondylotic myelopathy and those with spondylosis who were not operated upon, and to correlate these findings with clinical functionality at follow-up. Private practice. Of 16 consecutive patients with cervical spondylosis 8 underwent surgery (group I) and 8 were treated conservatively (group II). We compared TMS and MRI findings between these groups and we correlated central motor conduction times (CMCTs) and MRI-measured sagittal and parasagittal diameters of the spinal canal at baseline evaluation, with clinical functionality at 2-year follow-up. Group I CMCTs at the lower limbs correlated significantly with modified-JoA 2 years post surgery (r=-0.71, P<0.05), but MRI-measured diameters did not. In group II baseline TMS was unrevealing, contrary to significant spinal stenosis disclosed by MRI. The condition of none of these patients deteriorated at 2 years. CMCTs at the lower limbs, but not cervical spinal canal diameters, correlate with long-term functional outcome following surgical or conservative treatment.

  15. Low-Frequency Repetitive Transcranial Magnetic Stimulation Ameliorates Cognitive Function and Synaptic Plasticity in APP23/PS45 Mouse Model of Alzheimer’s Disease

    OpenAIRE

    Zhilin Huang; Zhilin Huang; Tao Tan; Tao Tan; Yehong Du; Yehong Du; Long Chen; Long Chen; Min Fu; Min Fu; Yanzhi Yu; Yanzhi Yu; Lu Zhang; Lu Zhang; Weihong Song

    2017-01-01

    Alzheimer’s disease (AD) is a chronic neurodegenerative disease leading to dementia, which is characterized by progressive memory loss and other cognitive dysfunctions. Recent studies have attested that noninvasive repetitive transcranial magnetic stimulation (rTMS) may help improve cognitive function in patients with AD. However, the majority of these studies have focused on the effects of high-frequency rTMS on cognitive function, and little is known about low-frequency rTMS in AD treatment...

  16. Risk of seizures in transcranial magnetic stimulation: a clinical review to inform consent process focused on bupropion

    Directory of Open Access Journals (Sweden)

    Dobek CE

    2015-11-01

    Full Text Available Christine E Dobek,1 Daniel M Blumberger,2 Jonathan Downar,3 Zafiris J Daskalakis,2 Fidel Vila-Rodriguez11Department of Psychiatry, Faculty of Medicine, Non-Invasive Neurostimulation Therapies (NINET Laboratory, University of British Columbia, Vancouver, BC, 2Department of Psychiatry, Centre for Addiction and Mental Health, 3Department of Psychiatry, University Health Network, University of Toronto, Toronto, ON, CanadaObjective: When considering repetitive transcranial magnetic stimulation (rTMS for major depressive disorder, clinicians often face a lack of detailed information on potential interactions between rTMS and pharmacotherapy. This is particularly relevant to patients receiving bupropion, a commonly prescribed antidepressant with lower risk of sexual side effects or weight increase, which has been associated with increased risk of seizure in particular populations. Our aim was to systematically review the information on seizures occurred with rTMS to identify the potential risk factors with attention to concurrent medications, particularly bupropion.Data sources: We conducted a systematic review through the databases PubMed, PsycINFO, and EMBASE between 1980 and June 2015. Additional articles were found using reference lists of relevant articles. Reporting of data follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.Study selection: Two reviewers independently screened articles reporting the occurrence of seizures during rTMS. Articles reporting seizures in epilepsy during rTMS were excluded. A total of 25 rTMS-induced seizures were included in the final review.Data extraction: Data were systematically extracted, and the authors of the applicable studies were contacted when appropriate to provide more detail about the seizure incidents.Results: Twenty-five seizures were identified. Potential risk factors emerged such as sleep deprivation, polypharmacy, and neurological insult. High-frequency-rTMS was

  17. Extended Remediation of Sleep Deprived-Induced Working Memory Deficits Using fMRI-guided Transcranial Magnetic Stimulation

    Science.gov (United States)

    Luber, Bruce; Steffener, Jason; Tucker, Adrienne; Habeck, Christian; Peterchev, Angel V.; Deng, Zhi-De; Basner, Robert C.; Stern, Yaakov; Lisanby, Sarah H.

    2013-01-01

    Study Objectives: We attempted to prevent the development of working memory (WM) impairments caused by sleep deprivation using fMRI-guided repetitive transcranial magnetic stimulation (rTMS). Novel aspects of our fMRI-guided rTMS paradigm included the use of sophisticated covariance methods to identify functional networks in imaging data, and the use of fMRI-targeted rTMS concurrent with task performance to modulate plasticity effects over a longer term. Design: Between-groups mixed model. Setting: TMS, MRI, and sleep laboratory study. Participants: 27 subjects (13 receiving Active rTMS, and 14 Sham) completed the sleep deprivation protocol, with another 21 (10 Active, 11 Sham) non-sleep deprived subjects run in a second experiment. Interventions: Our previous covariance analysis had identified a network, including occipital cortex, which demonstrated individual differences in resilience to the deleterious effects of sleep deprivation on WM performance. Five Hz rTMS was applied to left lateral occipital cortex while subjects performed a WM task during 4 sessions over the course of 2 days of total sleep deprivation. Measurements and Results: At the end of the sleep deprivation period, Sham sleep deprived subjects exhibited degraded performance in the WM task. In contrast, those receiving Active rTMS did not show the slowing and lapsing typical in sleep deprivation, and instead performed similarly to non- sleep deprived subjects. Importantly, the Active sleep deprivation group showed rTMS-induced facilitation of WM performance a full 18 hours after the last rTMS session. Conclusions: Over the course of sleep deprivation, these results indicate that rTMS applied concurrently with WM task performance affected neural circuitry involved in WM to prevent its full impact. Citation: Luber B; Steffener J; Tucker A; Habeck C; Peterchev AV; Deng ZD; Basner RC; Stern Y; Lisanby SH. Extended remediation of sleep deprived-induced working memory deficits using f

  18. Reduced neuronal activity in language-related regions after transcranial magnetic stimulation therapy for auditory verbal hallucinations.

    Science.gov (United States)

    Kindler, Jochen; Homan, Philipp; Jann, Kay; Federspiel, Andrea; Flury, Richard; Hauf, Martinus; Strik, Werner; Dierks, Thomas; Hubl, Daniela

    2013-03-15

    Transcranial magnetic stimulation (TMS) is a novel therapeutic approach, used in patients with pharmacoresistant auditory verbal hallucinations (AVH). To investigate the neurobiological effects of TMS on AVH, we measured cerebral blood flow with pseudo-continuous magnetic resonance-arterial spin labeling 20 ± 6 hours before and after TMS treatment. Thirty patients with schizophrenia or schizoaffective disorder were investigated. Fifteen patients received a 10-day TMS treatment to the left temporoparietal cortex, and 15 received the standard treatment. The stimulation location was chosen according to an individually determined language region determined by a functional magnetic resonance imaging language paradigm, which identified the sensorimotor language area, area Spt (sylvian parietotemporal), as the target region. TMS-treated patients showed positive clinical effects, which were indicated by a reduction in AVH scores (p ≤ .001). Cerebral blood flow was significantly decreased in the primary auditory cortex (p ≤ .001), left Broca's area (p ≤ .001), and cingulate gyrus (p ≤ .001). In control subjects, neither positive clinical effects nor cerebral blood flow decreases were detected. The decrease in cerebral blood flow in the primary auditory cortex correlated with the decrease in AVH scores (p ≤ .001). TMS reverses hyperactivity of language regions involved in the emergence of AVH. Area Spt acts as a gateway to the hallucination-generating cerebral network. Successful therapy corresponded to decreased cerebral blood flow in the primary auditory cortex, supporting its crucial role in triggering AVH and contributing to the physical quality of the false perceptions. Copyright © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  19. The effects of repetitive transcranial magnetic stimulation in obese females with binge eating disorder: a protocol for a double-blinded, randomized, sham-controlled trial.

    Science.gov (United States)

    Maranhão, Mara Fernandes; Estella, Nara Mendes; Cury, Maria Elisa Gisbert; Amigo, Veruska Lastoria; Picasso, Clarissa Mollinero; Berberian, Arthur; Campbell, Iain; Schmidt, Ulrike; Claudino, Angélica Medeiros

    2015-08-12

    Binge eating disorder is a new category in DSM-5 and highly associated with higher body mass index. The neural mechanisms that underlie binge eating are of great interest in order to improve treatment interventions. Brain mechanisms underlying drug and food craving are suggested to be similar: for example, both are reported to be associated with increased neural activity in the orbitofrontal and anterior cingulate cortex, and a diminished regulatory influence from lateral prefrontal circuits. Several studies have begun to assess the potential benefits of brain stimulation in reducing craving and addictive behaviors. Data from a study of a one-off session of transcranial magnetic stimulation in healthy women identified as strong cravers and of individuals with bulimic-type eating disorders, reported a reduction in food craving and binge eating episodes. This provides support for a more extensive investigation of the potential therapeutic benefits of transcranial magnetic stimulation. Lastly, brain imaging studies and a dimensional approach, will improve understanding of the neural correlates of the disorders and of the mode of action of transcranial magnetic stimulation. Sixty eligible obese females, with binge eating disorder, will be randomly allocated to receive 20 sessions of transcranial magnetic stimulation intervention (n = 30) or the sham transcranial magnetic stimulation intervention (n = 30) scattered 3 days/week. Thirty eligible controls will complete the baseline assessment. The primary outcome (number of binge eating episodes) will be assed at each treatment sessions, and 8 weeks after intervention completion (follow-up). It is hypothesized that mean weekly binge-eating episodes will be reduced in the intervention group, compared to the sham group, and that the effect will be maintained at follow-up. Despite the severity associated with Binge Eating Disorder, there are limited treatment options. This study is an important step in the development of more

  20. Transcranial magnetic stimulation and aging: Effects on spatial learning and memory after sleep deprivation in Octodon degus.

    Science.gov (United States)

    Estrada, C; Fernández-Gómez, F J; López, D; Gonzalez-Cuello, A; Tunez, I; Toledo, F; Blin, O; Bordet, R; Richardson, J C; Fernandez-Villalba, E; Herrero, M T

    2015-11-01

    The benefits of neuromodulatory procedures as a possible therapeutic application for cognitive rehabilitation have increased with the progress made in non-invasive modes of brain stimulation in aged-related disorders. Transcranial magnetic stimulation (TMS) is a non-invasive method used to examine multiple facets of the human brain and to ameliorate the impairment in cognition caused by Alzheimer's disease (AD). The present study was designed to evaluate how a chronic TMS treatment could improve learning and memory functions after sleep deprivation (SD) in old Octodon degus. SD was executed by gently handling to keep the animals awake throughout the night. Thirty young and twenty-four old O. degus females were divided in six groups (control, acute and chronic TMS treatment). Behavioral tests included; Radial Arm Maze (RAM), Barnes Maze (BM) and Novel Object Recognition (NOR). Although learning and memory functions improved in young animals with only one session of TMS treatment, a significant improvement in cognitive performance was seen in old animals after 4 and 7days of TMS, depending on the task that was performed. No side effects were observed following, which showed therapeutic potential for improving age-related cognitive performance. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Analysing concurrent transcranial magnetic stimulation and electroencephalographic data: A review and introduction to the open-source TESA software.

    Science.gov (United States)

    Rogasch, Nigel C; Sullivan, Caley; Thomson, Richard H; Rose, Nathan S; Bailey, Neil W; Fitzgerald, Paul B; Farzan, Faranak; Hernandez-Pavon, Julio C

    2017-02-15

    The concurrent use of transcranial magnetic stimulation with electroencephalography (TMS-EEG) is growing in popularity as a method for assessing various cortical properties such as excitability, oscillations and connectivity. However, this combination of methods is technically challenging, resulting in artifacts both during recording and following typical EEG analysis methods, which can distort the underlying neural signal. In this article, we review the causes of artifacts in EEG recordings resulting from TMS, as well as artifacts introduced during analysis (e.g. as the result of filtering over high-frequency, large amplitude artifacts). We then discuss methods for removing artifacts, and ways of designing pipelines to minimise analysis-related artifacts. Finally, we introduce the TMS-EEG signal analyser (TESA), an open-source extension for EEGLAB, which includes functions that are specific for TMS-EEG analysis, such as removing and interpolating the TMS pulse artifact, removing and minimising TMS-evoked muscle activity, and analysing TMS-evoked potentials. The aims of TESA are to provide users with easy access to current TMS-EEG analysis methods and to encourage direct comparisons of these methods and pipelines. It is hoped that providing open-source functions will aid in both improving and standardising analysis across the field of TMS-EEG research. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Transcranial magnetic stimulation as an investigative tool for motor dysfunction and recovery in stroke: an overview for neurorehabilitation clinicians.

    Science.gov (United States)

    Cortes, Mar; Black-Schaffer, Randie M; Edwards, Dylan J

    2012-07-01

    An improved understanding of motor dysfunction and recovery after stroke has important clinical implications that may lead to the design of more effective rehabilitation strategies for patients with hemiparesis. Transcranial magnetic stimulation (TMS) is a safe and painless tool that has been used in conjunction with other existing diagnostic tools to investigate motor pathophysiology in stroke patients. Since TMS emerged more than two decades ago, its application in clinical and basic neuroscience has expanded worldwide. TMS can quantify the corticomotor excitability properties of clinically affected and unaffected muscles and can probe local cortical networks as well as remote but functionally related areas. This provides novel insight into the physiology of neural circuits underlying motor dysfunction and brain reorganization during the motor recovery process. This important tool needs to be used with caution by clinical investigators, its limitations need to be understood, and the results should to be interpreted along with clinical evaluation in this patient population. In this review, we provide an overview of the rationale, implementation, and limitations of TMS to study stroke motor physiology. This knowledge may be useful to guide future rehabilitation treatments by assessing and promoting functional plasticity. © 2012 International Neuromodulation Society.

  3. Electroconvulsive therapy in the treatment of neuropsychiatric conditions and transcranial magnetic stimulation as a pathophysiological probe in neuropsychiatry.

    Science.gov (United States)

    McDonald, W M; Greenberg, B D

    2000-01-01

    It is a challenging task to review transcranial magnetic stimulation (TMS) studies in neuropsychiatric disorders alongside assessments of longstanding clinical applications of ECT as an empirical treatment. The task is challenging because TMS was developed as a probe of neural mechanisms, whereas, in marked contrast, ECT has been a clinical technique from its inception. Since the onset of modern psychopharmacology, the understanding of the potential applications of ECT to neuropsychiatric disorders is generally restricted to case reports of patients with intractable disease that have had at least a partial response to ECT. Studies of the possible efficacy of TMS in neuropsychiatric conditions have a significant advantage over ECT as the treatments are associated with less morbidity. The only serious known complication in TMS is a risk of seizures that may increase in patients with neuropsychiatric conditions such as course brain disease. Only cortical structures are themselves accessible to TMS using current technology. Present TMS techniques, however, seem capable of affecting activity in deeper brain structures that are functionally linked to cortical brain regions. TMS permits novel explorations of relationships between regional brain activity and symptoms of a number of neuropsychiatric disorders, as well as in research relating activity in functionally related brain regions to modulation of cognition and affective states in healthy individuals. This is particularly true at present because TMS and powerful neuroimaging and neuropsychological tools are all making rapid advances simultaneously.

  4. Image Artifacts in Concurrent Transcranial Magnetic Stimulation (TMS) and fMRI Caused by Leakage Currents: Modeling and Compensation

    Science.gov (United States)

    Weiskopf, Nikolaus; Josephs, Oliver; Ruff, Christian C; Blankenburg, Felix; Featherstone, Eric; Thomas, Anthony; Bestmann, Sven; Driver, Jon; Deichmann, Ralf

    2009-01-01

    Purpose To characterize and eliminate a new type of image artifact in concurrent transcranial magnetic stimulation and functional MRI (TMS-fMRI) caused by small leakage currents originating from the high-voltage capacitors in the TMS stimulator system. Materials and Methods The artifacts in echo-planar images (EPI) caused by leakage currents were characterized and quantified in numerical simulations and phantom studies with different phantom-coil geometries. A relay-diode combination was devised and inserted in the TMS circuit that shorts the leakage current. Its effectiveness for artifact reduction was assessed in a phantom scan resembling a realistic TMS-fMRI experiment. Results The leakage-current-induced signal changes exhibited a multipolar spatial pattern and the maxima exceeded 1% at realistic coil-cortex distances. The relay-diode combination effectively reduced the artifact to a negligible level. Conclusion The leakage-current artifacts potentially obscure effects of interest or lead to false-positives. Since the artifact depends on the experimental setup and design (eg, amplitude of the leakage current, coil orientation, paradigm, EPI parameters), we recommend its assessment for each experiment. The relay-diode combination can eliminate the artifacts if necessary. J. Magn. Reson. Imaging 2009;29:1211–1217. © 2009 Wiley-Liss, Inc. PMID:19388099

  5. Estimating resting motor thresholds in transcranial magnetic stimulation research and practice: a computer simulation evaluation of best methods.

    Science.gov (United States)

    Borckardt, Jeffrey J; Nahas, Ziad; Koola, Jejo; George, Mark S

    2006-09-01

    Resting motor threshold is the basic unit of dosing in transcranial magnetic stimulation (TMS) research and practice. There is little consensus on how best to estimate resting motor threshold with TMS, and only a few tools and resources are readily available to TMS researchers. The current study investigates the accuracy and efficiency of 5 different approaches to motor threshold assessment for TMS research and practice applications. Computer simulation models are used to test the efficiency and accuracy of 5 different adaptive parameter estimation by sequential testing (PEST) procedures. For each approach, data are presented with respect to the mean number of TMS trials necessary to reach the motor threshold estimate as well as the mean accuracy of the estimates. A simple nonparametric PEST procedure appears to provide the most accurate motor threshold estimates, but takes slightly longer (on average, 3.48 trials) to complete than a popular parametric alternative (maximum likelihood PEST). Recommendations are made for the best starting values for each of the approaches to maximize both efficiency and accuracy. In light of the computer simulation data provided in this article, the authors review and suggest which techniques might best fit different TMS research and clinical situations. Lastly, a free user-friendly software package is described and made available on the world wide web that allows users to run all of the motor threshold estimation procedures discussed in this article for clinical and research applications.

  6. Transcranial magnetic stimulation reveals two functionally distinct stages of motor cortex involvement during perception of emotional body language.

    Science.gov (United States)

    Borgomaneri, Sara; Gazzola, Valeria; Avenanti, Alessio

    2015-09-01

    Studies indicate that perceiving emotional body language recruits fronto-parietal regions involved in action execution. However, the nature of such motor activation is unclear. Using transcranial magnetic stimulation (TMS) we provide correlational and causative evidence of two distinct stages of motor cortex engagement during emotion perception. Participants observed pictures of body expressions and categorized them as happy, fearful or neutral while receiving TMS over the left or right motor cortex at 150 and 300 ms after picture onset. In the early phase (150 ms), we observed a reduction of excitability for happy and fearful emotional bodies that was specific to the right hemisphere and correlated with participants' disposition to feel personal distress. This 'orienting' inhibitory response to emotional bodies was also paralleled by a general drop in categorization accuracy when stimulating the right but not the left motor cortex. Conversely, at 300 ms, greater excitability for negative, positive and neutral movements was found in both hemispheres. This later motor facilitation marginally correlated with participants' tendency to assume the psychological perspectives of others and reflected simulation of the movement implied in the neutral and emotional body expressions. These findings highlight the motor system's involvement during perception of emotional bodies. They suggest that fast orienting reactions to emotional cues--reflecting neural processing necessary for visual perception--occur before motor features of the observed emotional expression are simulated in the motor system and that distinct empathic dispositions influence these two neural motor phenomena. Implications for theories of embodied simulation are discussed.

  7. Image artifacts in concurrent transcranial magnetic stimulation (TMS) and fMRI caused by leakage currents: modeling and compensation.

    Science.gov (United States)

    Weiskopf, Nikolaus; Josephs, Oliver; Ruff, Christian C; Blankenburg, Felix; Featherstone, Eric; Thomas, Anthony; Bestmann, Sven; Driver, Jon; Deichmann, Ralf

    2009-05-01

    To characterize and eliminate a new type of image artifact in concurrent transcranial magnetic stimulation and functional MRI (TMS-fMRI) caused by small leakage currents originating from the high-voltage capacitors in the TMS stimulator system. The artifacts in echo-planar images (EPI) caused by leakage currents were characterized and quantified in numerical simulations and phantom studies with different phantom-coil geometries. A relay-diode combination was devised and inserted in the TMS circuit that shorts the leakage current. Its effectiveness for artifact reduction was assessed in a phantom scan resembling a realistic TMS-fMRI experiment. The leakage-current-induced signal changes exhibited a multipolar spatial pattern and the maxima exceeded 1% at realistic coil-cortex distances. The relay-diode combination effectively reduced the artifact to a negligible level. The leakage-current artifacts potentially obscure effects of interest or lead to false-positives. Since the artifact depends on the experimental setup and design (eg, amplitude of the leakage current, coil orientation, paradigm, EPI parameters), we recommend its assessment for each experiment. The relay-diode combination can eliminate the artifacts if necessary.

  8. Does Inhibitory Repetitive Transcranial Magnetic Stimulation Augment Functional Task Practice to Improve Arm Recovery in Chronic Stroke?

    Directory of Open Access Journals (Sweden)

    Dorian K. Rose

    2014-01-01

    Full Text Available Introduction. Restoration of upper extremity (UE functional use remains a challenge for individuals following stroke. Repetitive transcranial magnetic stimulation (rTMS is a noninvasive modality that modulates cortical excitability and is being explored as a means to potentially ameliorate these deficits. The purpose of this study was to evaluate, in the presence of chronic stroke, the effects of low-frequency rTMS to the contralesional hemisphere as an adjuvant to functional task practice (FTP, to improve UE functional ability. Methods. Twenty-two individuals with chronic stroke and subsequent moderate UE deficits were randomized to receive 16 sessions (4 times/week for 4 weeks of either real-rTMS or sham-rTMS followed by 1-hour of paretic UE FTP. Results. No differences in UE outcomes were revealed between the real-rTMS and sham-rTMS intervention groups. After adjusting for baseline differences, no differences were revealed in contralesional cortical excitability postintervention. In a secondary analysis, data pooled across both groups revealed small, but statistically significant, improvements in UE behavioral measures. Conclusions. rTMS did not augment changes in UE motor ability in this population of individuals with chronic stroke. The chronicity of our participant cohort and their degree of UE motor impairment may have contributed to inability to produce marked effects using rTMS.

  9. A meta-analysis of the effects of aging on motor cortex neurophysiology assessed by transcranial magnetic stimulation.

    Science.gov (United States)

    Bhandari, Apoorva; Radhu, Natasha; Farzan, Faranak; Mulsant, Benoit H; Rajji, Tarek K; Daskalakis, Zafiris J; Blumberger, Daniel M

    2016-08-01

    Transcranial magnetic stimulation (TMS) is a non-invasive tool used for studying cortical excitability and plasticity in the human brain. This review aims to quantitatively synthesize the literature on age-related differences in cortical excitability and plasticity, examined by TMS. A literature search was conducted using MEDLINE, Embase, and PsycINFO from 1980 to December 2015. We extracted studies with healthy old (50-89years) versus young (16-49years) individuals that utilized the following TMS measures: resting motor threshold (RMT), short-interval cortical inhibition (SICI), short-latency afferent inhibition (SAI), cortical silent period (CSP), intracortical facilitation (ICF), and paired associative stimulation (PAS). We found a significant increase in RMT (g=0.414, 95% confidence interval (CI) [0.284, 0.544], pmotor cortex. Alterations in the ability to regulate cortical excitability, sensorimotor integration and plasticity may underlie several age-related motor deficits. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. The variability of motor evoked potential latencies in neurosurgical motor mapping by preoperative navigated transcranial magnetic stimulation.

    Science.gov (United States)

    Sollmann, Nico; Bulubas, Lucia; Tanigawa, Noriko; Zimmer, Claus; Meyer, Bernhard; Krieg, Sandro M

    2017-01-03

    Recording of motor evoked potentials (MEPs) is used during navigated transcranial magnetic stimulation (nTMS) motor mapping to locate motor function in the human brain. However, factors potentially underlying MEP latency variability in neurosurgical motor mapping are vastly unknown. In the context of this study, one hundred brain tumor patients underwent preoperative nTMS-based motor mapping of the tumor hemisphere between 2010 and 2013. Fourteen predefined predictor variables were recorded, and MEP latencies of abductor pollicis brevis muscle (APB), abductor digiti minimi muscle (ADM), and flexor carpi radialis muscle (FCR) were analyzed using linear mixed-effect multiple regression analysis with the forward step-wise model comparison approach. Common factors (relevant to APB, ADM, and FCR) for MEP latency variability were gender, most likely due to body height, and antiepileptic drug (AED) intake. Muscle-specific factors (relevant to APB, ADM, or FCR) for MEP latency variability were resting motor threshold (rMT), tumor side, and tumor location. Based on a large cohort of neurosurgical patients, this study provides data on a wide range of clinical factors that may underlie MEP latency variability. The factors that significantly contributed to MEP latency variability should be standardly recorded and taken into consideration during neurosurgical motor mapping.

  11. Clinical Factors Underlying the Inter-individual Variability of the Resting Motor Threshold in Navigated Transcranial Magnetic Stimulation Motor Mapping.

    Science.gov (United States)

    Sollmann, Nico; Tanigawa, Noriko; Bulubas, Lucia; Sabih, Jamil; Zimmer, Claus; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

    2017-01-01

    Correctly determining individual's resting motor threshold (rMT) is crucial for accurate and reliable mapping by navigated transcranial magnetic stimulation (nTMS), which is especially true for preoperative motor mapping in brain tumor patients. However, systematic data analysis on clinical factors underlying inter-individual rMT variability in neurosurgical motor mapping is sparse. The present study examined 14 preselected clinical factors that may underlie inter-individual rMT variability by performing multiple regression analysis (backward, followed by forward model comparisons) on the nTMS motor mapping data of 100 brain tumor patients. Data were collected from preoperative motor mapping of abductor pollicis brevis (APB), abductor digiti minimi (ADM), and flexor carpi radialis (FCR) muscle representations among these patients. While edema and age at exam in the ADM model only jointly reduced the unexplained variance significantly, the other factors kept in the ADM model (gender, antiepileptic drug intake, and motor deficit) and each of the factors kept in the APB and FCR models independently significantly reduced the unexplained variance. Hence, several clinical parameters contribute to inter-individual rMT variability and should be taken into account during initial and follow-up motor mappings. Thus, the present study adds basic evidence on inter-individual rMT variability, whereby some of the parameters are specific to brain tumor patients.

  12. Effects of visual deprivation on primary motor cortex excitability: a study on healthy subjects based on repetitive transcranial magnetic stimulation.

    Science.gov (United States)

    Cambieri, Chiara; Iacovelli, Elisa; Gori, Maria Cristina; Onesti, Emanuela; Ceccanti, Marco; Frasca, Vittorio; Inghilleri, Maurizio

    2017-07-01

    We investigated whether rapid changes in visual input or dark adaptation modify primary motor cortex (M1) excitability in healthy subjects. Repetitive transcranial magnetic stimulation (rTMS), consisting of 10 stimuli delivered at 5 Hz at 120% of the resting motor threshold, was delivered over the M1 in 14 healthy volunteers. They were instructed to relax under eyes-open (EO) and eyes-closed (EC) resting conditions. Two experimental sessions were performed. In the first session, subjects were tested under both EO and EC conditions in order to determine whether short visual deprivation affected M1 excitability as tested through changes in the motor-evoked potential (MEP) amplitude during rTMS. In the second session, rTMS was delivered both under EO conditions with room lights on and after 30 min of blindfolding to evaluate the effects of prolonged visual deprivation on M1 excitability. Short-term visual deprivation lasting 2.5 s left the MEP facilitation unchanged during the 5-Hz rTMS trains, while 30 min of blindfolding significantly reduced MEP facilitation. Short-term visual deprivation did not significantly affect M1 excitability, whereas dark adaptation reduced rTMS-induced MEP facilitation, modulating motor cortical excitability.

  13. Transcranial magnetic stimulation as an investigative tool for motor dysfunction and recovery in stroke: an overview for neurorehabilitation clinicians

    Science.gov (United States)

    Cortes, Mar; Black-Schaffer, Randie M; Edwards, Dylan J

    2012-01-01

    Rationale An improved understanding of motor dysfunction and recovery after stroke has important clinical implications that may lead to the design of more effective rehabilitation strategies for patients with hemiparesis. Scope Transcranial magnetic stimulation (TMS) is a safe and painless tool that has been used in conjunction with other existing diagnostic tools to investigate motor pathophysiology in stroke patients. Since TMS emerged over two decades ago, its application in clinical and basic neuroscience has expanded worldwide. TMS can quantify the corticomotor excitability properties of clinically affected and unaffected muscles, and probe local cortical networks, as well as remote but functionally related areas. This provides novel insight into the physiology of neural circuits underlying motor dysfunction, and brain reorganization during the motor recovery process. This important tool needs to be used with caution by clinical investigators, its limitations need to be understood and the results should be interpreted along with clinical evaluation in this patient population. Summary In this review, we provide an overview of the rationale, implementation and limitations of TMS to study stroke motor physiology. This knowledge may be useful to guide future rehabilitation treatments by assessing and promoting functional plasticity. PMID:22624621

  14. Intermittent theta-burst transcranial magnetic stimulation for autism spectrum disorder: an open-label pilot study

    Directory of Open Access Journals (Sweden)

    Caio Abujadi

    2017-12-01

    Full Text Available Objective: Theta-burst stimulation (TBS modulates synaptic plasticity more efficiently than standard repetitive transcranial magnetic stimulation delivery and may be a promising modality for neuropsychiatric disorders such as autism spectrum disorder (ASD. At present there are few effective interventions for prefrontal cortex dysfunction in ASD. We report on an open-label, pilot study of intermittent TBS (iTBS to target executive function deficits and restricted, repetitive behaviors in male children and adolescents with ASD. Methods: Ten right-handed, male participants, aged 9-17 years with ASD were enrolled in an open-label trial of iTBS treatment. Fifteen sessions of neuronavigated iTBS at 100% motor threshold targeting the right dorsolateral prefrontal cortex were delivered over 3 weeks. Results: Parent report scores on the Repetitive Behavior Scale Revised and the Yale-Brown Obsessive Compulsive Scale demonstrated improvements with iTBS treatment. Participants demonstrated improvements in perseverative errors on the Wisconsin Card Sorting Test and total time for the Stroop test. The iTBS treatments were well tolerated with no serious adverse effects. Conclusion: These preliminary results suggest that further controlled interventional studies of iTBS for ASD are warranted.

  15. Topographic contribution of early visual cortex to short-term memory consolidation: a transcranial magnetic stimulation study.

    Science.gov (United States)

    van de Ven, Vincent; Jacobs, Christianne; Sack, Alexander T

    2012-01-04

    The neural correlates for retention of visual information in visual short-term memory are considered separate from those of sensory encoding. However, recent findings suggest that sensory areas may play a role also in short-term memory. We investigated the functional relevance, spatial specificity, and temporal characteristics of human early visual cortex in the consolidation of capacity-limited topographic visual memory using transcranial magnetic stimulation (TMS). Topographically specific TMS pulses were delivered over lateralized occipital cortex at 100, 200, or 400 ms into the retention phase of a modified change detection task with low or high memory loads. For the high but not the low memory load, we found decreased memory performance for memory trials in the visual field contralateral, but not ipsilateral to the side of TMS, when pulses were delivered at 200 ms into the retention interval. A behavioral version of the TMS experiment, in which a distractor stimulus (memory mask) replaced the TMS pulses, further corroborated these findings. Our findings suggest that retinotopic visual cortex contributes to the short-term consolidation of topographic visual memory during early stages of the retention of visual information. Further, TMS-induced interference decreased the strength (amplitude) of the memory representation, which most strongly affected the high memory load trials.

  16. An Investigation of the Late Excitatory Potentials in the Hand following Transcranial Magnetic Stimulation in Early Alzheimer's Disease

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    Christina Balla

    2014-11-01

    Full Text Available Background: Recent neuroimaging studies in humans support the clinical observations that the motor cortex is affected early in the course of Alzheimer's disease (AD. Patients and Methods: We measured the silent period (SP induced by transcranial magnetic stimulation in AD patients in the very early stage of the disease, and we explored whether and in which way the pharmacologic manipulation of the cholinergic system could modify it. Results: An increase in the duration of the SP was observed in AD patients in the early stage in comparison to controls. After 2 months of treatment with donepezil, the duration did not differ significantly from that of normal subjects. The results of our study show a fragmentation and an enlargement of the SP in the presence of multiple late excitatory potentials (LEPs in early untreated AD patients. These LEPs were also modulated by donepezil. Conclusions: The results suggest an early functional impairment of cholinergic neurotransmission in AD. The disturbance in acetylcholine output in early AD leads to a decrease in excitability of the motor system.

  17. Bilateral Repetitive Transcranial Magnetic Stimulation Combined with Intensive Swallowing Rehabilitation for Chronic Stroke Dysphagia: A Case Series Study

    Directory of Open Access Journals (Sweden)

    Ryo Momosaki

    2014-03-01

    Full Text Available The purpose of this study was to clarify the safety and feasibility of a 6-day protocol of bilateral repetitive transcranial magnetic stimulation (rTMS combined with intensive swallowing rehabilitation for chronic poststroke dysphagia. In-hospital treatment was provided to 4 poststroke patients (age at treatment: 56-80 years; interval between onset of stroke and treatment: 24-37 months with dysphagia. Over 6 consecutive days, each patient received 10 sessions of rTMS at 3 Hz applied to the pharyngeal motor cortex bilaterally, followed by 20 min of intensive swallowing rehabilitation exercise. The swallowing function was evaluated by the Penetration Aspiration Scale (PAS, Modified Mann Assessment of Swallowing Ability (MMASA, Functional Oral Intake Scale (FOIS, laryngeal elevation delay time (LEDT and Repetitive Saliva-Swallowing Test (RSST on admission and at discharge. All patients completed the 6-day treatment protocol and none showed any adverse reactions throughout the treatment. The combination treatment improved laryngeal elevation delay time in all patients. Our proposed protocol of rTMS plus swallowing rehabilitation exercise seems to be safe and feasible for chronic stroke dysphagia, although its efficacy needs to be confirmed in a large number of patients.

  18. Left dorsolateral prefrontal transcranial magnetic stimulation (TMS): sleep factor changes during treatment in patients with pharmacoresistant major depressive disorder.

    Science.gov (United States)

    Rosenquist, Peter B; Krystal, Andrew; Heart, Karen L; Demitrack, Mark A; McCall, W Vaughn

    2013-01-30

    As they alleviate major depressive disorder, antidepressant therapies may improve associated sleep disturbances, but may also have inherent sedating or activating properties. We examined sleep changes during a multicenter, sham-controlled, trial of transcranial magnetic stimulation (TMS) therapy for pharmacoresistant MDD. Medication-free outpatients (N=301) were randomized to receive active (N=155) or sham (N=146) TMS for 6 weeks. Depression severity was rated with the Montgomery-Asberg Depression Rating Scale, the 24-item Hamilton Depression Scale (HAMD), and the Inventory of Depressive Symptoms-Self Report (IDS-SR). Assessments were performed at baseline, 2, 4, and 6 week time points. Sleep was assessed using the HAMD and IDS-SR sleep factors; comparison between treatment groups employed ANCOVA model. No significant differences were identified between the active and sham treatment groups in either the HAMD or IDS-SR sleep factor scores at any time during treatment. Sleep difficulty as an adverse event over the length of the study did not differ between active and sham treatment. Stratified by end of acute treatment responder status, there was a statistically significant improvement in both the HAMD sleep factor score and the IDS-SR sleep factor during acute treatment in both the active and sham treatment conditions. TMS exerts no intrinsic effect upon sleep in patients with MDD. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. An Investigation of the Late Excitatory Potentials in the Hand following Transcranial Magnetic Stimulation in Early Alzheimer's Disease.

    Science.gov (United States)

    Balla, Christina; Maertens de Noordhout, Alain; Pepin, Jean Louis

    2014-01-01

    Recent neuroimaging studies in humans support the clinical observations that the motor cortex is affected early in the course of Alzheimer's disease (AD). We measured the silent period (SP) induced by transcranial magnetic stimulation in AD patients in the very early stage of the disease, and we explored whether and in which way the pharmacologic manipulation of the cholinergic system could modify it. An increase in the duration of the SP was observed in AD patients in the early stage in comparison to controls. After 2 months of treatment with donepezil, the duration did not differ significantly from that of normal subjects. The results of our study show a fragmentation and an enlargement of the SP in the presence of multiple late excitatory potentials (LEPs) in early untreated AD patients. These LEPs were also modulated by donepezil. The results suggest an early functional impairment of cholinergic neurotransmission in AD. The disturbance in acetylcholine output in early AD leads to a decrease in excitability of the motor system.

  20. Significant reduction in phantom limb pain after low-frequency repetitive transcranial magnetic stimulation to the primary sensory cortex.

    Science.gov (United States)

    Grammer, Geoffrey G; Williams-Joseph, Sonya; Cesar, Ashley; Adkinson, David K; Spevak, Christopher

    2015-01-01

    Phantom limb pain (PLP) is believed to be linked to the reorganization of the deafferented sensory cortex. We present a case of a patient with upper extremity PLP who was successfully treated with repetitive transcranial magnetic stimulation (rTMS). We treated an active duty service member who suffered an amputation of his right upper extremity after sustaining a blast injury in Afghanistan. He had 28 sessions of alternating sequences of rTMS to the left dorsolateral prefrontal cortex and primary sensory cortex of the left cerebral hemisphere. Pain intensity was assessed with the Visual Analogue Scale. We delivered 1 Hz stimulation to the sensory cortex corresponding to the area of amputation five times a week. After 4 sessions, the patient's pain decreased from a Visual Analogue Scale of 5 to 2. Left 10 Hz stimulation was added and after 28 sessions, the pain decreased from 2 to 1. Our findings support that rTMS was an effective modality for this patient in treating his PLP. The significance of 10 Hz stimulation is unknown because of the lack of an effect size and is possibly associated with a floor effect. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  1. The Efficacy of High-Frequency Repetitive Transcranial Magnetic Stimulation for Improving Apathy in Chronic Stroke Patients.

    Science.gov (United States)

    Sasaki, Nobuyuki; Hara, Takatoshi; Yamada, Naoki; Niimi, Masachika; Kakuda, Wataru; Abo, Masahiro

    2017-01-01

    Although repetitive transcranial magnetic stimulation (rTMS) for hemiparesis is beneficial, so far no study has examined the usefulness of rTMS for apathy. Thirteen patients with chronic stroke were assigned randomly to 2 groups: rTMS group (n = 7) and sham stimulation group (n = 6). The patients received 5 sessions of either high-frequency rTMS over the region spanning from the dorsal anterior cingulate cortex (dACC) to medial prefrontal cortex (mPFC) or sham stimulation for 5 days. The severity of apathy was evaluated using the Apathy Scale (AS) and the severity of depression was evaluated using the Quick Inventory of Depressive Symptomatology (QIDS) serially before and after the 5-day protocol. The AS and QIDS scores were significantly improved in the rTMS group, although they were not changed in the sham stimulation group. The degree of change in the AS score was significantly greater in the rTMS group than that in the sham stimulation group. The degree of change in the QIDS score was greater in the rTMS group than that in the sham stimulation group, although the difference was not statistically significant. The application of high frequency rTMS over the dACC and mPFC may be a useful intervention for apathy due to stroke. © 2017 S. Karger AG, Basel.

  2. Empathy moderates the effect of repetitive transcranial magnetic stimulation of the right dorsolateral prefrontal cortex on costly punishment.

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    Martin Brüne

    Full Text Available Humans incur considerable costs to punish unfairness directed towards themselves or others. Recent studies using repetitive transcranial magnetic stimulation (rTMS suggest that the right dorsolateral prefrontal cortex (DLPFC is causally involved in such strategic decisions. Presently, two partly divergent hypotheses are discussed, suggesting either that the right DLPFC is necessary to control selfish motives by implementing culturally transmitted social norms, or is involved in suppressing emotion-driven prepotent responses to perceived unfairness. Accordingly, we studied the role of the DLPFC in costly (i.e. third party punishment by applying rTMS to the left and right DLPFC before playing a Dictator Game with the option to punish observed unfair behavior (DG-P. In addition, sham stimulation took place. Individual differences in empathy were assessed with the German version of the Interpersonal Reactivity Index. Costly punishment increased (non-significantly upon disruption of the right--but not the left--DLPFC as compared to sham stimulation. However, empathy emerged as a highly significant moderator variable of the effect of rTMS over the right, but not left, DLPFC, suggesting that the right DLPFC is involved in controlling prepotent emotional responses to observed unfairness, depending on individual differences in empathy.

  3. Food cravings and the effects of left prefrontal repetitive transcranial magnetic stimulation using an improved sham condition

    Directory of Open Access Journals (Sweden)

    Kelly eBarth

    2011-03-01

    Full Text Available This study examined whether a single session of repetitive transcranial magnetic stimulation (rTMS of the left prefrontal cortex would inhibit food cravings in healthy women who endorsed frequent food cravings. Ten participants viewed images of food and completed ratings for food cravings before and after receiving either real or sham rTMS over the left prefrontal cortex (10Hz, 100% rMT, 10 seconds-on, 20 seconds-off for 15 minutes; 3000 pulses. Sham TMS was matched with real TMS with respect to perceived painfulness of the stimulation. Each participant received both real and sham rTMS in random order and were blind to the condition in a within-subject cross-over design. With an improved sham control condition, prefrontal rTMS inhibited food cravings no better than sham rTMS. The mild pain from the real and sham rTMS may distract or inhibit food craving, and the decreased craving may not be caused by the effect of rTMS itself. Further studies are needed to elucidate whether rTMS has any true effects on food craving and whether painful stimuli inhibit food or other cravings. A sham condition which matches the painfulness is important to understand the true effects of TMS on behaviors and diseases.

  4. The value of repetitive transcranial magnetic stimulation (rTMS) for the treatment of anxiety disorders: an integrative review.

    Science.gov (United States)

    Paes, Flávia; Machado, Sergio; Arias-Carrión, Oscar; Velasques, Bruna; Teixeira, Silmar; Budde, Henning; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro; Huston, Joseph P; Sack, Alexander T; Nardi, Antonio E

    2011-08-01

    Unlike for depression, only few studies are available today investigating the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) for anxiety disorders. This review aims to provide information on the current research approaches and main findings regarding the therapeutic use of rTMS in the context of various anxiety disorders. Although positive results have frequently been reported in both open and randomized controlled studies, our review of all identified studies indicates that at present no conclusive evidence of the efficacy of rTMS for the treatment for anxiety disorders is provided. Several treatment parameters have been used, making the interpretation of the results difficult. Moreover, sham-controlled research has often been unable to distinguish between response to rTMS and sham treatment. However, there is a limitation in the rTMS methods that likely impacts only the superficial cortical layers. It is not possible to directly stimulate more distant cortical areas, and also subcortical areas, relevant to the pathogenesis of anxiety disorders, though such effects in subcortical areas are thought to be indirect, via trans-synaptic connections. We thus recommend further studies to clearly determine the role of rTMS in the treatment of anxiety disorders. Key advances in combining TMS with neuroimaging technology may aid in such future developments.

  5. The effect of music on corticospinal excitability is related to the perceived emotion: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Giovannelli, Fabio; Banfi, Chiara; Borgheresi, Alessandra; Fiori, Elisa; Innocenti, Iglis; Rossi, Simone; Zaccara, Gaetano; Viggiano, Maria Pia; Cincotta, Massimo

    2013-03-01

    Transcranial magnetic stimulation (TMS) and neuroimaging studies suggest a functional link between the emotion-related brain areas and the motor system. It is not well understood, however, whether the motor cortex activity is modulated by specific emotions experienced during music listening. In 23 healthy volunteers, we recorded the motor evoked potentials (MEP) following TMS to investigate the corticospinal excitability while subjects listened to music pieces evoking different emotions (happiness, sadness, fear, and displeasure), an emotionally neutral piece, and a control stimulus (musical scale). Quality and intensity of emotions were previously rated in an additional group of 30 healthy subjects. Fear-related music significantly increased the MEP size compared to the neutral piece and the control stimulus. This effect was not seen with music inducing other emotional experiences and was not related to changes in autonomic variables (respiration rate, heart rate). Current data indicate that also in a musical context, the excitability of the corticomotoneuronal system is related to the emotion expressed by the listened piece. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Can neurophysiologic measures serve as biomarkers for the efficacy of repetitive transcranial magnetic stimulation treatment of major depressive disorder?

    Science.gov (United States)

    Kobayashi, Brian; Cook, Ian A; Hunter, Aimee M; Minzenberg, Michael J; Krantz, David E; Leuchter, Andrew F

    2017-04-01

    Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for Major Depressive Disorder (MDD). There are clinical data that support the efficacy of many different approaches to rTMS treatment, and it remains unclear what combination of stimulation parameters is optimal to relieve depressive symptoms. Because of the costs and complexity of studies that would be necessary to explore and compare the large number of combinations of rTMS treatment parameters, it would be useful to establish reliable surrogate biomarkers of treatment efficacy that could be used to compare different approaches to treatment. This study reviews the evidence that neurophysiologic measures of cortical excitability could be used as biomarkers for screening different rTMS treatment paradigms. It examines evidence that: (1) changes in excitability are related to the mechanism of action of rTMS; (2) rTMS has consistent effects on measures of excitability that could constitute reliable biomarkers; and (3) changes in excitability are related to the outcomes of rTMS treatment of MDD. An increasing body of evidence indicates that these neurophysiologic measures have the potential to serve as reliable biomarkers for screening different approaches to rTMS treatment of MDD.

  7. Repetitive transcranial magnetic stimulation for tinnitus treatment: no enhancement by the dopamine and noradrenaline reuptake inhibitor bupropion.

    Science.gov (United States)

    Kleinjung, Tobias; Steffens, Thomas; Landgrebe, Michael; Vielsmeier, Veronika; Frank, Elmar; Burger, Julia; Strutz, Juergen; Hajak, Göran; Langguth, Berthold

    2011-04-01

    Repetitive transcranial magnetic stimulation (rTMS) of the temporal cortex has shown beneficial effects in patients with chronic tinnitus. Recent preclinical data in healthy controls suggest that the effects of low-frequency rTMS can be enhanced by dopaminergic drugs. We investigated whether application of the dopamine reuptake inhibitor bupropion increases the clinical effects of low-frequency rTMS over the auditory cortex in tinnitus patients. Eighteen subjects with chronic tinnitus received 10 sessions of 1 Hz rTMS (2000 pulses/day, 110% motor threshold) applied to the left temporal cortex. In addition, these subjects received one dosage of 150 mg bupropion (Wellbutrin XL/Elontril) 4 hours before each TMS session. Treatment outcome was assessed with a tinnitus questionnaire over a 3-month period. Treatment effects were compared with a control group of 100 tinnitus patients matched for age, tinnitus duration, and tinnitus questionnaire baseline scores, who received the same rTMS treatment without prior bupropion application. For the whole sample, there was a significant effect of rTMS treatment over time. There were no significant differences between the bupropion and the control group. Our data suggest that 150 mg bupropion administration does not enhance the effect of rTMS in the treatment of tinnitus. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Transcranial magnetic stimulation of visual cortex in memory: cortical state, interference and reactivation of visual content in memory.

    Science.gov (United States)

    van de Ven, Vincent; Sack, Alexander T

    2013-01-01

    Memory for perceptual events includes the neural representation of the sensory information at short or longer time scales. Recent transcranial magnetic stimulation (TMS) studies of human visual cortex provided evidence that sensory cortex contributes to memory functions. In this review, we provide an exhaustive overview of these studies and ascertain how well the available evidence supports the idea of a causal role of sensory cortex in memory retention and retrieval. We discuss the validity and implications of the studies using a number of methodological and theoretical criteria that are relevant for brain stimulation of visual cortex. While most studies applied TMS to visual cortex to interfere with memory functions, a handful of pioneering studies used TMS to 'reactivate' memories in visual cortex. Interestingly, similar effects of TMS on memory were found in different memory tasks, which suggests that different memory systems share a neural mechanism of memory in visual cortex. At the same time, this neural mechanism likely interacts with higher order brain areas. Based on this overview and evaluation, we provide a first attempt to an integrative framework that describes how sensory processes contribute to memory in visual cortex, and how higher order areas contribute to this mechanism. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. The effects of high-frequency transcranial magnetic stimulation combined with transcutaneous electrical stimulation in a severe stroke patient

    Directory of Open Access Journals (Sweden)

    Soichiro Koyama

    2012-12-01

    Full Text Available The case report describes the effects of 5 Hz repetitive transcranial magnetic stimulation (rTMS combined with transcutaneous electrical stimulation (TES in a patient with severe stroke. The patient was a 69-year-old male who was affected by a left middle cerebral artery infarction. The patient had no movement in his right hand. To assess the effects, cerebral blood flow and motor function were measured before and after treatment. This treatment delivered rTMS over the affected M1 with TES at the paretic wrist extensor muscles for 10 days. The regional cerebral blood flow (rCBF in the entire brain was measured by positronemission tomography. To evaluate the motor function, the Fugl-Meyer assessment (FMA was used. After treatment, the rCBF was increased (except for the stimulated region, and the FMA score was slightly improved. These results suggest the potential therapeutic use of rTMS combined with TES for recovery in severe stroke.

  10. Bilateral responses of prefrontal and motor cortices to repetitive transcranial magnetic stimulation as measured by functional near infrared spectroscopy

    Science.gov (United States)

    Tian, Fenghua; Kozel, Frank Andrew; Dhamne, Sameer; McClintock, Shawn M.; Croarkin, Paul; Mapes, Kimberly; Husain, Mustafa M.; Liu, Hanli

    2009-02-01

    Simultaneously acquiring cortical functional Near Infrared Spectroscopy (fNIRS) during repeated Transcranial Magnetic Stimulation (rTMS) offers the possibility of directly investigating the effects of rTMS on brain regions without quantifiable behavioral changes. In this study, the left motor cortex and subsequently the left prefrontal cortex were stimulated at 1 Hz while fNIRS data was simultaneously acquired. Changes in hemodynamic signals were measured on both ipsilateral and contralateral sides. In each cortex, a significantly larger decrease in the concentration of oxygenated hemoglobin and a smaller increase in the concentration of deoxygenated hemoglobin during the stimulation periods were observed in both the motor and prefrontal cortices. The ipsilateral and contralateral changes showed high temporal consistency. Same experiment was repeated for each subject 2 or 3 days later. The hemodynamic responses associated with the stimulation showed good reproducibility in two sessions. To our knowledge, this is the first report of simultaneous fNIRS measurement of ipsilateral and contralateral changes of either the motor or prefrontal cortex during rTMS stimulation.

  11. Effects of Repetitive Transcranial Magnetic Stimulation in the Rehabilitation of Communication and Deglutition Disorders: Systematic Review of Randomized Controlled Trials.

    Science.gov (United States)

    Gadenz, Camila Dalbosco; Moreira, Tais de Campos; Capobianco, Dirce Maria; Cassol, Mauriceia

    2015-01-01

    To systematically review randomized controlled trials that evaluate the effects of repetitive transcranial magnetic stimulation (rTMS) on rehabilitation aspects related to communication and swallowing functions. A search was conducted on PubMed, Clinical Trials, Cochrane Library, and ASHA electronic databases. Studies were judged according to the eligibility criteria and analyzed by 2 independent and blinded researchers. We analyzed 9 studies: 4 about aphasia, 3 about dysphagia, 1 about dysarthria in Parkinson's disease and 1 about linguistic deficits in Alzheimer's disease. All aphasia studies used low-frequency rTMS to stimulate Broca's homologous area. High-frequency rTMS was applied over the pharyngoesophageal cortex from the left and/or right hemisphere in the dysphagia studies and over the left dorsolateral prefrontal cortex in the Parkinson's and Alzheimer's studies. Two aphasia and all dysphagia studies showed a significant improvement of the disorder, compared to the sham group. The other 2 studies related to aphasia found a benefit restricted to subgroups with a severe case or injury on the anterior portion of the language cortical area, respectively, whereas the Alzheimer's study demonstrated positive effects specific to auditory comprehension. There were no changes for vocal function in the Parkinson's study. The benefits of the technique and its applicability in neurogenic disorders related to communication and deglutition are still uncertain. Therefore, other randomized controlled trials are needed to clarify the optimal stimulation protocol for each disorder studied and its real effects. © 2015 S. Karger AG, Basel.

  12. Clinical improvement in patients with borderline personality disorder after treatment with repetitive transcranial magnetic stimulation: preliminary results

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    Julian Reyes-López

    2017-06-01

    Full Text Available Objective: Current treatment of borderline personality disorder (BPD consists of psychotherapy and pharmacological interventions. However, the use of repetitive transcranial magnetic stimulation (rTMS could be beneficial to improve some BPD symptoms. The objective of this study was to evaluate clinical improvement in patients with BPD after application of rTMS over the right or left dorsolateral prefrontal cortex (DLPFC. Method: Twenty-nine patients with BPD from the National Institute of Psychiatry, Mexico, were randomized in two groups to receive 15 sessions of rTMS applied over the right (1 Hz, n=15 or left (5 Hz, n=14 DLPFC. Improvement was measured by the Clinical Global Impression Scale for BPD (CGI-BPD, Borderline Evaluation of Severity Over Time (BEST, Beck Depression Inventory (BDI, Hamilton Anxiety Rating Scale (HAM-A, and Barratt Impulsiveness Scale (BIS. Results: Intragroup comparison showed significant (p < 0.05 reductions in every psychopathologic domain of the CGI-BPD and in the total scores of all scales in both groups. Conclusions: Both protocols produced global improvement in severity and symptoms of BPD, particularly in impulsiveness, affective instability, and anger. Further studies are warranted to explore the therapeutic effect of rTMS in BPD. Clinical trial registration: NCT02273674.

  13. Deep transcranial magnetic stimulation add-on for the treatment of auditory hallucinations: a double-blind study

    Directory of Open Access Journals (Sweden)

    Rosenberg Oded

    2012-05-01

    Full Text Available Abstract Background About 25% of schizophrenia patients with auditory hallucinations are refractory to pharmacotherapy and electroconvulsive therapy. We conducted a deep transcranial magnetic stimulation (TMS pilot study in order to evaluate the potential clinical benefit of repeated left temporoparietal cortex stimulation in these patients. The results were encouraging, but a sham-controlled study was needed to rule out a placebo effect. Methods A total of 18 schizophrenic patients with refractory auditory hallucinations were recruited, from Beer Yaakov MHC and other hospitals outpatient populations. Patients received 10 daily treatment sessions with low-frequency (1 Hz for 10 min deep TMS applied over the left temporoparietal cortex, using the H1 coil at the intensity of 110% of the motor threshold. Procedure was either real or sham according to patient randomization. Patients were evaluated via the Auditory Hallucinations Rating Scale, Scale for the Assessment of Positive Symptoms-Negative Symptoms, Clinical Global Impressions, and Quality of Life Questionnaire. Results In all, 10 patients completed the treatment (10 TMS sessions. Auditory hallucination scores of both groups improved; however, there was no statistical difference in any of the scales between the active and the sham treated groups. Conclusions Low-frequency deep TMS to the left temporoparietal cortex using the protocol mentioned above has no statistically significant effect on auditory hallucinations or the other clinical scales measured in schizophrenic patients. Trial Registration Clinicaltrials.gov identifier: NCT00564096.

  14. Modulation of the Left Prefrontal Cortex with High Frequency Repetitive Transcranial Magnetic Stimulation Facilitates Gait in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Amer M. Burhan

    2015-01-01

    Full Text Available Multiple Sclerosis (MS is a chronic central nervous system (CNS demyelinating disease. Gait abnormalities are common and disabling in patients with MS with limited treatment options available. Emerging evidence suggests a role of prefrontal attention networks in modulating gait. High-frequency repetitive transcranial magnetic stimulation (rTMS is known to enhance cortical excitability in stimulated cortex and its correlates. We investigated the effect of high-frequency left prefrontal rTMS on gait parameters in a 51-year-old Caucasian male with chronic relapsing/remitting MS with residual disabling attention and gait symptoms. Patient received 6 Hz, rTMS at 90% motor threshold using figure of eight coil centered on F3 location (using 10-20 electroencephalography (EEG lead localization system. GAITRite gait analysis system was used to collect objective gait measures before and after one session and in another occasion three consecutive daily sessions of rTMS. Two-tailed within subject repeated measure t-test showed significant enhancement in ambulation time, gait velocity, and cadence after three consecutive daily sessions of rTMS. Modulating left prefrontal cortex excitability using rTMS resulted in significant change in gait parameters after three sessions. To our knowledge, this is the first report that demonstrates the effect of rTMS applied to the prefrontal cortex on gait in MS patients.

  15. Transcranial Magnetic Stimulation: An Automated Procedure to Obtain Coil-specific Models for Field Calculations

    DEFF Research Database (Denmark)

    Madsen, Kristoffer Hougaard; Ewald, Lars; Siebner, Hartwig R.

    2015-01-01

    potential of the TMS coils. Objective: To develop an approach to reconstruct the magnetic vector potential based on automated measurements. Methods: We implemented a setup that simultaneously measures the three components of the magnetic field with high spatial resolution. This is complemented by a novel...

  16. Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study.

    Science.gov (United States)

    Jung, JeYoung; Bungert, Andreas; Bowtell, Richard; Jackson, Stephen R

    2016-01-01

    A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in most experimental tasks, however there has been little attempt to measure neural changes linked to vertex TMS. Here we directly test this assumption by using a concurrent TMS/fMRI paradigm in which we investigate fMRI blood-oxygenation-level-dependent (BOLD) signal changes across the whole brain linked to vertex stimulation. Thirty-two healthy participants to part in this study. Twenty-one were stimulated at the vertex, at 120% of resting motor threshold (RMT), with short bursts of 1 Hz TMS, while functional magnetic resonance imaging (fMRI) BOLD images were acquired. As a control condition, we delivered TMS pulses over the left primary motor cortex using identical parameters to 11 other participants. Vertex stimulation did not evoke increased BOLD activation at the stimulated site. By contrast we observed widespread BOLD deactivations across the brain, including regions within the default mode network (DMN). To examine the effects of vertex stimulation a functional connectivity analysis was conducted. The results demonstrated that stimulating the vertex with suprathreshold TMS reduced neural activity in brain regions related to the DMN but did not influence the functional connectivity of this network. Our findings provide brain imaging evidence in support of the use of vertex simulation as a control condition in TMS but confirm that vertex TMS induces regional widespread decreases in BOLD activation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  17. The Hand Motor Hotspot is not Always Located in the Hand Knob: A Neuronavigated Transcranial Magnetic Stimulation Study.

    Science.gov (United States)

    Ahdab, Rechdi; Ayache, Samar S; Brugières, Pierre; Farhat, Wassim H; Lefaucheur, Jean-Pascal

    2016-07-01

    The hand motor hot spot (hMHS) is one of the most salient parameters in transcranial magnetic stimulation (TMS) practice, notably used for targeting. It is commonly accepted that the hMHS corresponds to the hand representation within the primary motor cortex (M1). Anatomical and imaging studies locate this representation in a region of the central sulcus called the "hand knob". The aim of this study was to determine if the hMHS location corresponds to its expected location at the hand knob. Twelve healthy volunteers and eleven patients with chronic neuropathic pain of various origins, but not related to a brain lesion, were enrolled. Morphological magnetic resonance imaging of the brain was normal in all participants. Both hemispheres were studied in all participants except four (two patients and two healthy subjects). Cortical mapping of the hand motor area was conducted using a TMS-dedicated navigation system and recording motor evoked potentials (MEPs) in the contralateral first dorsal interosseous (FDI) muscle. We then determined the anatomical position of the hMHS, defined as the stimulation site providing the largest FDI-MEPs. In 45 % of hemispheres of normal subjects and 25 % of hemispheres of pain patients, the hMHS was located over the central sulcus, most frequently at the level of the hand knob. However, in the other cases, the hMHS was located outside M1, most frequently anteriorly over the precentral or middle frontal gyrus. This study shows that the hMHS does not always correspond to the hand knob and M1 location in healthy subjects or patients. Therefore, image-guided navigation is needed to improve the anatomical accuracy of TMS targeting, even for M1.

  18. Effect of transcranial static magnetic field stimulation over the sensorimotor cortex on somatosensory evoked potentials in humans.

    Science.gov (United States)

    Kirimoto, Hikari; Tamaki, Hiroyuki; Matsumoto, Takuya; Sugawara, Kazuhiro; Suzuki, Makoto; Oyama, Mineo; Onishi, Hideaki

    2014-01-01

    The motor cortex in the human brain can be modulated by the application of transcranial static magnetic field stimulation (tSMS) through the scalp. However, the effect of tSMS on the excitability of the primary somatosensory cortex (S1) in humans has never been examined. This study was performed to investigate the possibility of non-invasive modulation of S1 excitability by the application of tSMS in healthy humans. tSMS and sham stimulation over the sensorimotor cortex were applied to 10 subjects for periods of 10 and 15 min. Somatosensory evoked potentials (SEPs) following right median nerve stimulation were recorded before and immediately after, 5 min after, and 10 min after tSMS from sites C3' and F3 of the international 10-20 system of electrode placement. In another session, SEPs were recorded from 6 of the 10 subjects every 3 min during 15 min of tSMS. Amplitudes of the N20 component of SEPs at C3' significantly decreased immediately after 10 and 15 min of tSMS by up to 20%, returning to baseline by 10 min after intervention. tSMS applied while recording SEPs every 3 min and sham stimulation had no effect on SEP. tSMS is able to modulate cortical somatosensory processing in humans, and thus might be a useful tool for inducing plasticity in cortical somatosensory processing. Lack of change in the amplitude of SEPs with tSMS implies that use of peripheral nerve stimulation to cause SEPs antagonizes alteration of the function of membrane ion channels during exposure to static magnetic fields. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. A novel approach for monitoring writing interferences during navigated transcranial magnetic stimulation mappings of writing related cortical areas.

    Science.gov (United States)

    Rogić Vidaković, Maja; Gabelica, Dragan; Vujović, Igor; Šoda, Joško; Batarelo, Nikolina; Džimbeg, Andrija; Zmajević Schönwald, Marina; Rotim, Krešimir; Đogaš, Zoran

    2015-11-30

    It has recently been shown that navigated repetitive transcranial magnetic stimulation (nTMS) is useful in preoperative neurosurgical mapping of motor and language brain areas. In TMS mapping of motor cortices the evoked responses can be quantitatively monitored by electromyographic (EMG) recordings. No such setup exists for monitoring of writing during nTMS mappings of writing related cortical areas. We present a novel approach for monitoring writing during nTMS mappings of motor writing related cortical areas. To our best knowledge, this is the first demonstration of quantitative monitoring of motor evoked responses from hand by EMG, and of pen related activity during writing with our custom made pen, together with the application of chronometric TMS design and patterned protocol of rTMS. The method was applied in four healthy subjects participating in writing during nTMS mapping of the premotor cortical area corresponding to BA 6 and close to the superior frontal sulcus. The results showed that stimulation impaired writing in all subjects. The corresponding spectra of measured signal related to writing movements was observed in the frequency band 0-20 Hz. Magnetic stimulation affected writing by suppressing normal writing frequency band. The proposed setup for monitoring of writing provides additional quantitative data for monitoring and the analysis of rTMS induced writing response modifications. The setup can be useful for investigation of neurophysiologic mechanisms of writing, for therapeutic effects of nTMS, and in preoperative mapping of language cortical areas in patients undergoing brain surgery. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Network Mechanisms of Clinical Response to Transcranial Magnetic Stimulation in Posttraumatic Stress Disorder and Major Depressive Disorder.

    Science.gov (United States)

    Philip, Noah S; Barredo, Jennifer; van 't Wout-Frank, Mascha; Tyrka, Audrey R; Price, Lawrence H; Carpenter, Linda L

    2018-02-01

    Repetitive transcranial magnetic stimulation (TMS) therapy can modulate pathological neural network functional connectivity in major depressive disorder (MDD). Posttraumatic stress disorder is often comorbid with MDD, and symptoms of both disorders can be alleviated with TMS therapy. This is the first study to evaluate TMS-associated changes in connectivity in patients with comorbid posttraumatic stress disorder and MDD. Resting-state functional connectivity magnetic resonance imaging was acquired before and after TMS therapy in 33 adult outpatients in a prospective open trial. TMS at 5 Hz was delivered, in up to 40 daily sessions, to the left dorsolateral prefrontal cortex. Analyses used a priori seeds relevant to TMS, posttraumatic stress disorder, or MDD (subgenual anterior cingulate cortex [sgACC], left dorsolateral prefrontal cortex, hippocampus, and basolateral amygdala) to identify imaging predictors of response and to evaluate clinically relevant changes in connectivity after TMS, followed by leave-one-out cross-validation. Imaging results were explored using data-driven multivoxel pattern activation. More negative pretreatment connectivity between the sgACC and the default mode network predicted clinical improvement, as did more positive amygdala-to-ventromedial prefrontal cortex connectivity. After TMS, symptom reduction was associated with reduced connectivity between the sgACC and the default mode network, left dorsolateral prefrontal cortex, and insula, and reduced connectivity between the hippocampus and the salience network. Multivoxel pattern activation confirmed seed-based predictors and correlates of treatment outcomes. These results highlight the central role of the sgACC, default mode network, and salience network as predictors of TMS response and suggest their involvement in mechanisms of action. Furthermore, this work indicates that there may be network-based biomarkers of clinical response relevant to these commonly comorbid disorders

  1. MR-based measurements and simulations of the magnetic field created by a realistic transcranial magnetic stimulation (TMS) coil and stimulator.

    Science.gov (United States)

    Mandija, Stefano; Petrov, Petar I; Neggers, Sebastian F W; Luijten, Peter R; van den Berg, Cornelis A T

    2016-11-01

    Transcranial magnetic stimulation (TMS) is an emerging technique that allows non-invasive neurostimulation. However, the correct validation of electromagnetic models of typical TMS coils and the correct assessment of the incident TMS field (B TMS ) produced by standard TMS stimulators are still lacking. Such a validation can be performed by mapping B TMS produced by a realistic TMS setup. In this study, we show that MRI can provide precise quantification of the magnetic field produced by a realistic TMS coil and a clinically used TMS stimulator in the region in which neurostimulation occurs. Measurements of the phase accumulation created by TMS pulses applied during a tailored MR sequence were performed in a phantom. Dedicated hardware was developed to synchronize a typical, clinically used, TMS setup with a 3-T MR scanner. For comparison purposes, electromagnetic simulations of B TMS were performed. MR-based measurements allow the mapping and quantification of B TMS starting 2.5 cm from the TMS coil. For closer regions, the intra-voxel dephasing induced by B TMS prohibits TMS field measurements. For 1% TMS output, the maximum measured value was ~0.1 mT. Simulations reflect quantitatively the experimental data. These measurements can be used to validate electromagnetic models of TMS coils, to guide TMS coil positioning, and for dosimetry and quality assessment of concurrent TMS-MRI studies without the need for crude methods, such as motor threshold, for stimulation dose determination. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Shifts in connectivity during procedural learning after motor cortex stimulation: A combined transcranial magnetic stimulation/functional magnetic resonance imaging study.

    Science.gov (United States)

    Steel, Adam; Song, Sunbin; Bageac, Devin; Knutson, Kristine M; Keisler, Aysha; Saad, Ziad S; Gotts, Stephen J; Wassermann, Eric M; Wilkinson, Leonora

    2016-01-01

    Inhibitory transcranial magnetic stimulation (TMS), of which continuous theta burst stimulation (cTBS) is a common form, has been used to inhibit cortical areas during investigations of their function. cTBS applied to the primary motor area (M1) depresses motor output excitability via a local effect and impairs procedural motor learning. This could be due to an effect on M1 itself and/or to changes in its connectivity with other nodes in the learning network. To investigate this issue, we used functional magnetic resonance imaging to measure changes in brain activation and connectivity during implicit procedural learning after real and sham cTBS of M1. Compared to sham, real cTBS impaired motor sequence learning, but caused no local or distant changes in brain activation. Rather, it reduced functional connectivity between motor (M1, dorsal premotor & supplementary motor areas) and visual (superior & inferior occipital gyri) areas. It also increased connectivity between frontal associative (superior & inferior frontal gyri), cingulate (dorsal & middle cingulate), and temporal areas. This potentially compensatory shift in coupling, from a motor-based learning network to an associative learning network accounts for the behavioral effects of cTBS of M1. The findings suggest that the inhibitory TMS affects behavior via relatively subtle and distributed effects on connectivity within networks, rather than by taking the stimulated area "offline". Published by Elsevier Ltd.

  3. Comparison between short train, monophasic and biphasic repetitive transcranial magnetic stimulation (rTMS) of the human motor cortex.

    Science.gov (United States)

    Arai, Noritoshi; Okabe, Shingo; Furubayashi, Toshiaki; Terao, Yasuo; Yuasa, Kaoru; Ugawa, Yoshikazu

    2005-03-01

    To compare motor evoked potentials (MEPs) elicited by short train, monophasic, repetitive transcranial magnetic stimulations (rTMS) with those by short train, biphasic rTMS. Subjects were 13 healthy volunteers. Surface electromyographic (EMG) responses were recorded from the right first dorsal interosseous muscle (FDI) in several different stimulation conditions. We gave both monophasic and biphasic rTMS over the motor cortex at a frequency of 0.5, 1, 2 or 3Hz. To study excitability changes of the spinal cord, we also performed 3Hz rTMS at the foramen magnum level [Ugawa Y, Uesaka Y, Terao Y, Hanajima R, Kanazawa I. Magnetic stimulation of corticospinal pathways at the foramen magnum level in humans. Ann Neurol 1994;36:618-24]. We measured the size and latency of each of 20 MEPs recorded in the different stimulation conditions. 2 or 3Hz stimulation with either monophasic or biphasic pulses evoked MEPs that gradually increased in amplitude with the later MEPs being significantly larger than the earlier ones. Monophasic rTMS showed much more facilitation than biphasic stimulation, particularly at 3Hz. Stimulation at the foramen magnum level at 3Hz elicited fairly constant MEPs. The enhancement of cortical MEPs with no changes of responses to foramen magnum level stimulation suggests that the facilitation occurred at the motor cortex. We hypothesize that monophasic TMS has a stronger short-term effect during repetitive stimulation than biphasic TMS because monophasic pulses preferentially activate one population of neurons oriented in the same direction so that their effects readily summate. Biphasic pulses in contrast may activate several different populations of neurons (both facilitatory and inhibitory) so that summation of the effects is not so clear as with monophasic pulses. When single stimuli are applied, however, biphasic TMS is thought to be more powerful than monophasic TMS because the peak-to-peak amplitude of stimulus pulse is higher and its duration is

  4. Repetitive transcranial magnetic stimulation (rTMS) influences spatial cognition and modulates hippocampal structural synaptic plasticity in aging mice.

    Science.gov (United States)

    Ma, Jun; Zhang, Zhanchi; Kang, Lin; Geng, Dandan; Wang, Yanyong; Wang, Mingwei; Cui, Huixian

    2014-10-01

    Normal aging is characteristic with the gradual decline in cognitive function associated with the progressive reduction of structural and functional plasticity in the hippocampus. Repetitive transcranial magnetic stimulation (rTMS) has developed into a novel neurological and psychiatric tool that can be used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency rTMS (≤1Hz) affects synaptic plasticity in rats with vascular dementia (VaD), and it ameliorates the spatial cognitive ability in mice with Aβ1-42-mediated memory deficits, but there are little concerns about the effects of rTMS on normal aging related cognition and synaptic plasticity changes. Thus, the current study investigated the effects of rTMS on spatial memory behavior, neuron and synapse morphology in the hippocampus, and synaptic protein markers and brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) in normal aging mice, to illustrate the mechanisms of rTMS in regulating cognitive capacity. Relative to adult animals, aging caused hippocampal-dependent cognitive impairment, simultaneously inhibited the activation of the BDNF-TrkB signaling pathway, reduced the transcription and expression of synaptic protein markers: synaptophysin (SYN), growth associated protein 43 (GAP43) and post-synaptic density protein 95 (PSD95), as well as decreased synapse density and PSD (post-synaptic density) thickness. Interestingly, rTMS with low intensity (110% average resting motor threshold intensity, 1Hz, LIMS) triggered the activation of BDNF and TrkB, upregulated the level of synaptic protein markers, and increased synapse density and thickened PSD, and further reversed the spatial cognition dysfunction in aging mice. Conversely, high-intensity magnetic stimulation (150% average resting motor threshold intensity, 1Hz, HIMS) appeared to be detrimental, inducing thinning of PSDs, disordered synaptic structure, and a large number of

  5. Assessing the Effects of Repetitive Transcranial Magnetic Stimulation on Cognition in Major Depressive Disorder Using Computerized Cognitive Testing.

    Science.gov (United States)

    Galletly, Cherrie; Gill, Shane; Rigby, Ashlee; Carnell, Benjamin Luke; Clarke, Patrick

    2016-09-01

    A range of different treatment approaches are available for depression; however, there is an ongoing concern about the cognitive impairment associated with many treatments. This study investigated the effect of treatment with repetitive transcranial magnetic stimulation (rTMS) on cognition in patients with major depressive disorder. Cognition before and after treatment was assessed using a computerized cognitive testing battery, which provided comprehensive assessment across a range of cognitive domains. This was a naturalistic study involving patients attending an outpatient clinical rTMS service. A total of 63 patients with treatment-resistant depression completed the IntegNeuro cognitive test battery, a well-validated comprehensive computerized assessment tool before and after receiving 18 or 20 treatments of sequential bilateral rTMS. Change in the various cognitive domains was assessed, and analyses were undertaken to determine whether any change in cognition was associated with a change in rating of depression severity. There was a significant decrease in Hamilton Depression Rating Scale scores from baseline to posttreatment. There was no decline in performance on any of the cognitive tests. There were significant improvements in maze completion time and the number of errors in the maze task. However, these were accounted for by improvement in mood when change in depressive symptoms was included as a covariate. This open-label study provides further support for the efficacy and safety of rTMS as a treatment option for people with major depressive disorder in a naturalistic clinical setting. Using a comprehensive, robust computerized battery of cognitive tests, the current study indicated that there was no significant cognitive impairment associated with rTMS and that any improvements in cognitive functioning were associated with a reduction in depressive symptoms.

  6. Neurocognitive Effects of Repetitive Transcranial Magnetic Stimulation (rTMS in Adolescents with Major Depressive Disorder (MDD

    Directory of Open Access Journals (Sweden)

    Christopher A Wall

    2013-12-01

    Full Text Available Objectives: It is estimated that 30% to 40% of adolescents with major depressive disorder (MDD do not receive full benefit from current antidepressant therapies. Repetitive transcranial magnetic stimulation (rTMS is a novel therapy approved by the US FDA to treat adults with MDD. Research suggests rTMS is not associated with adverse neurocognitive effects in adult populations; however, there is no documentation of its neurocognitive effects in adolescents. This is a secondary post hoc analysis of neurocognitive outcome in adolescents who were treated with open label rTMS in two separate studies. Methods: Eighteen patients (mean age, 16.2 ± 1.1 years; 11 females, 7 males with MDD who failed to adequately respond to at least 1 antidepressant agent were enrolled in the studies. Fourteen patients completed all 30 rTMS treatments (5 days/week, 120% of motor threshold, 10 Hz, 3,000 stimulations per session applied to the left dorsolateral prefrontal cortex (L-DLPFC. Depression was rated using the Children’s Depression Rating Scale-Revised (CDRS-R. Neurocognitive evaluation was performed at baseline and after completion of 30 rTMS treatments with the Children’s Auditory Verbal Learning Test (CAVLT and Delis-Kaplan Executive Function System (DKEFS Trail Making Test. Results: Over the course of 30 rTMS treatments, adolescents showed a substantial decrease in depression severity and a statistically significant improvement in memory and delayed verbal recall. Other learning and memory indices and executive function remained intact. Neither participants nor their family members reported clinically meaningful changes in neurocognitive function. Conclusion: These preliminary findings suggest rTMS does not adversely impact neurocognitive functioning in adolescents and may provide subtle enhancement of verbal memory as measured by the CAVLT. Further controlled investigations are warranted to confirm and extend these findings.

  7. Repetition suppression in transcranial magnetic stimulation-induced motor-evoked potentials is modulated by cortical inhibition.

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    Kallioniemi, E; Pääkkönen, A; Julkunen, P

    2015-12-03

    Transcranial magnetic stimulation (TMS) can be applied to modulate cortical phenomena. The modulation effect is dependent on the applied stimulation frequency. Repetition suppression (RS) has been demonstrated in the motor system using TMS with short suprathreshold 1-Hz stimulation trains repeated at long inter-train intervals. RS has been reported to occur in the resting motor-evoked potentials (MEPs) with respect to the first pulse in a train of stimuli. Although this RS in the motor system has been described in previous studies, the neuronal origin of the phenomenon is still poorly understood. The present study evaluated RS in three TMS-induced motor responses; resting and active MEPs as well as corticospinal silent periods (SPs) in order to clarify the mechanism behind TMS-induced RS. We studied 10 healthy right-handed subjects using trains of four stimuli with stimulation intensities of 120% of the resting motor threshold (rMT) and 120% of the silent period threshold for an SP duration of 30 ms (SPT30). Inter-trial interval was 20s, with a 1-s inter-stimulus interval within the trains. We confirmed that RS appears in resting MEPs (p 0.792). SPs, on the contrary, lengthened (p < 0.001) indicating modulation of cortical inhibition. The effects of the two stimulation intensities exhibited a similar trend; however, the SPT30 evoked a more profound inhibitory effect compared to that achieved by rMT. Moreover, the resting MEP amplitudes and SP durations correlated (rho ⩽ -0.674, p < 0.001) and the pre-TMS EMG level did not differ between stimuli in resting MEPs (F = 0.0, p ⩾ 0.999). These results imply that the attenuation of response size seen in resting MEPs might originate from increasing activity of inhibitory GABAergic interneurons which relay the characteristics of SPs. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Artifact correction and source analysis of early electroencephalographic responses evoked by transcranial magnetic stimulation over primary motor cortex.

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    Litvak, Vladimir; Komssi, Soile; Scherg, Michael; Hoechstetter, Karsten; Classen, Joseph; Zaaroor, Menashe; Pratt, Hillel; Kahkonen, Seppo

    2007-08-01

    Analyzing the brain responses to transcranial magnetic stimulation (TMS) using electroencephalography (EEG) is a promising method for the assessment of functional cortical connectivity and excitability of areas accessible to this stimulation. However, until now it has been difficult to analyze the EEG responses during the several tens of milliseconds immediately following the stimulus due to TMS-induced artifacts. In the present study we show that by combining a specially adapted recording system with software artifact correction it is possible to remove a major part of the artifact and analyze the cortical responses as early as 10 ms after TMS. We used this methodology to examine responses of left and right primary motor cortex (M1) to TMS at different intensities. Based on the artifact-corrected data we propose a model for the cortical activation following M1 stimulation. The model revealed the same basic response sequence for both hemispheres. A large part of the response could be accounted for by two sources: a source close to the stimulation site (peaking approximately 15 ms after the stimulus) and a midline frontal source ipsilateral to the stimulus (peaking approximately 25 ms). In addition the model suggests responses in ipsilateral temporo-parietal junction areas (approximately 35 ms) and ipsilateral (approximately 30 ms) and middle (approximately 50 ms) cerebellum. Statistical analysis revealed significant dependence on stimulation intensity for the ipsilateral midline frontal source. The methodology developed in the present study paves the way for the detailed study of early responses to TMS in a wide variety of brain areas.

  9. The anterior intraparietal sulcus mediates grasp execution, independent of requirement to update: new insights from transcranial magnetic stimulation.

    Science.gov (United States)

    Rice, Nichola J; Tunik, Eugene; Grafton, Scott T

    2006-08-02

    Although a role of the intraparietal sulcus (IPS) in grasping is becoming evident, the specific contribution of regions within the IPS remains undefined. In this vein, transcranial magnetic stimulation (TMS) was delivered to the anterior (aIPS), middle (mIPS), and caudal (cIPS) IPS in two tasks designed to dissociate the potential roles of the IPS in either grasp planning or execution (task 1) and its involvement in error detection or error correction (task 2). Determining the involvement of specific regions of the IPS in perceptual (planning and error detection) versus motor (execution and correction) components of grasping allowed us to assess the ecological validity of competing computational models attempting to simulate reach-to-grasp movements. In task 1, we demonstrate that, when no on-line adjustment is necessary, TMS to aIPS (but not mIPS or cIPS) disrupts grasping; this disruption is only elicited when TMS is applied during the execution (but not the planning) phase of the movement. Task 2 reveals that TMS to aIPS (but not mIPS or cIPS) disrupts grasping in the presence of a perturbation; this disruption is only elicited when TMS is applied during the error correction (but not error detection) phase of the movement. We propose that the specific contribution of the aIPS in grasping is in the on-line computation of a difference vector based on motor goal, efference copy, and sensory inputs. This computation is performed for both stable and perturbed motor goals.

  10. Electric field estimation of deep transcranial magnetic stimulation clinically used for the treatment of neuropsychiatric disorders in anatomical head models.

    Science.gov (United States)

    Parazzini, Marta; Fiocchi, Serena; Chiaramello, Emma; Roth, Yiftach; Zangen, Abraham; Ravazzani, Paolo

    2017-05-01

    Literature studies showed the ability to treat neuropsychiatric disorders using H1 coil, developed for the deep Transcranial Magnetic Stimulation (dTMS). Despite the positive results of the clinical studies, the electric field (E) distributions inside the brain induced by this coil when it is positioned on the scalp according to the clinical studies themselves are not yet precisely estimated. This study aims to characterize the E distributions due to the H1 coil in the brain of two realistic human models by computational electromagnetic techniques and to compare them with the ones due to the figure-of-8 coil, traditionally used in TMS and positioned as such to simulate the clinical experiments. Despite inter-individual differences, our results show that the dorsolateral prefrontal cortex is the region preferentially stimulated by both H1 and figure-of-8 coil when they are placed in the position on the scalp according to the clinical studies, with a more broad and non-focal distribution in the case of H1 coil. Moreover, the H1 coil spreads more than the figure-of-8 coil both in the prefrontal cortex and medial prefrontal cortex and towards some deeper brain structures and it is characterized by a higher penetration depth in the frontal lobe. This work highlights the importance of the knowledge of the electric field distribution in the brain tissues to interpret the outcomes of the experimental studies and to optimize the treatments. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. Transcranial and spinal cord magnetic stimulation in treatment of spasticity: a literature review and meta-analysis.

    Science.gov (United States)

    Korzhova, Julia; Sinitsyn, Dmitry; Chervyakov, Alexander; Poydasheva, Alexandra; Zakharova, Maria; Suponeva, Natalia; Chernikova, Lyudmila; Piradov, Michael

    2018-02-01

    Spasticity is associated with various diseases of the nervous system. Current treatments such as drug therapy, botulinum toxin injections, kinesitherapy, and physiotherapy are not sufficiently effective in a large number of patients. Transcranial magnetic stimulation (TMS) can be considered as an alternative method of treatment. The purpose of this article was to conduct a systematic review and meta-analysis of all available publications assessing the efficacy of repetitive TMS in treatment of spasticity. Search for articles was conducted in databases PubMed, Willey, and Google. Keywords included "TMS", "spasticity", "TMS and spasticity", "non-invasive brain stimulation", and "non-invasive spinal cord stimulation". The difference in scores according to the Modified Ashworth Scale (MAS) for one joint before and after treatment was taken as the effect size. We found 26 articles that examined the TMS efficacy in treatment of spasticity. Meta-analysis included 6 trials comprising 149 patients who underwent real stimulation or simulation. No statistically significant difference in the effect of real and simulated stimulation was found in stroke patients. In patients with spinal cord injury and spasticity, the mean effect size value and the 95% confidence interval were -0.80 and (-1.12, -0.49), respectively, in a group of real stimulation; in the case of simulated stimulation, these parameters were 0.15 and (-0.30, -0.00), respectively. Statistically significant differences between groups of real stimulation and simulation were demonstrated for using high-frequency repetitive TMS or iTBS mode for the M1 area of the spastic leg (P=0.0002). According to the meta-analysis, the statistically significant effect of TMS in the form of reduced spasticity was demonstrated only for the developed due to lesions at the brain stem and spinal cord level. To clarify the amount of the antispasmodic effect of repetitive TMS at other lesion levels, in particular in patients with

  12. Differences in Motor Evoked Potentials Induced in Rats by Transcranial Magnetic Stimulation under Two Separate Anesthetics: Implications for Plasticity Studies.

    Science.gov (United States)

    Sykes, Matthew; Matheson, Natalie A; Brownjohn, Philip W; Tang, Alexander D; Rodger, Jennifer; Shemmell, Jonathan B H; Reynolds, John N J

    2016-01-01

    Repetitive transcranial magnetic stimulation (rTMS) is primarily used in humans to change the state of corticospinal excitability. To assess the efficacy of different rTMS stimulation protocols, motor evoked potentials (MEPs) are used as a readout due to their non-invasive nature. Stimulation of the motor cortex produces a response in a targeted muscle, and the amplitude of this twitch provides an indirect measure of the current state of the cortex. When applied to the motor cortex, rTMS can alter MEP amplitude, however, results are variable between participants and across studies. In addition, the mechanisms underlying any change and its locus are poorly understood. In order to better understand these effects, MEPs have been investigated in vivo in animal models, primarily in rats. One major difference in protocols between rats and humans is the use of general anesthesia in animal experiments. Anesthetics are known to affect plasticity-like mechanisms and so may contaminate the effects of an rTMS protocol. In the present study, we explored the effect of anesthetic on MEP amplitude, recorded before and after intermittent theta burst stimulation (iTBS), a patterned rTMS protocol with reported facilitatory effects. MEPs were assessed in the brachioradialis muscle of the upper forelimb under two anesthetics: a xylazine/zoletil combination and urethane. We found MEPs could be induced under both anesthetics, with no differences in the resting motor threshold or the average baseline amplitudes. However, MEPs were highly variable between animals under both anesthetics, with the xylazine/zoletil combination showing higher variability and most prominently a rise in amplitude across the baseline recording period. Interestingly, application of iTBS did not facilitate MEP amplitude under either anesthetic condition. Although it is important to underpin human application of TMS with mechanistic examination of effects in animals, caution must be taken when selecting an

  13. Descending motor pathways and cortical physiology after spinal cord injury assessed by transcranial magnetic stimulation: a systematic review.

    Science.gov (United States)

    Nardone, Raffaele; Höller, Yvonne; Brigo, Francesco; Orioli, Andrea; Tezzon, Frediano; Schwenker, Kerstin; Christova, Monica; Golaszewski, Stefan; Trinka, Eugen

    2015-09-04

    We performed here a systematic review of the studies using transcranial magnetic stimulation (TMS) as a research and clinical tool in patients with spinal cord injury (SCI). Motor evoked potentials (MEPs) elicited by TMS represent a highly accurate diagnostic test that can supplement clinical examination and neuroimaging findings in the assessment of SCI functional level. MEPs allows to monitor the changes in motor function and evaluate the effects of the different therapeutic approaches. Moreover, TMS represents a useful non-invasive approach for studying cortical physiology, and may be helpful in elucidating the pathophysiological mechanisms of brain reorganization after SCI. Measures of motor cortex reactivity, e.g., the short interval intracortical inhibition and the cortical silent period, seem to point to an increased cortical excitability. However, the results of TMS studies are sometimes contradictory or divergent, and should be replicated in a larger sample of subjects. Understanding the functional changes at brain level and defining their effects on clinical outcome is of crucial importance for development of evidence-based rehabilitation therapy. TMS techniques may help in identifying neurophysiological biomarkers that can reliably assess the extent of neural damage, elucidate the mechanisms of neural repair, predict clinical outcome, and identify therapeutic targets. Some researchers have begun to therapeutically use repetitive TMS (rTMS) in patients with SCI. Initial studies revealed that rTMS can induce acute and short duration beneficial effects especially on spasticity and neuropathic pain, but the evidence is to date still very preliminary and well-designed clinical trials are warranted. This article is part of a Special Issue entitled SI: Spinal cord injury. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Cortical plasticity of motor-eloquent areas measured by navigated transcranial magnetic stimulation in patients with glioma.

    Science.gov (United States)

    Conway, Neal; Wildschuetz, Noémie; Moser, Tobias; Bulubas, Lucia; Sollmann, Nico; Tanigawa, Noriko; Meyer, Bernhard; Krieg, Sandro M

    2017-11-01

    OBJECTIVE The goal of this study was to obtain a better understanding of the mechanisms underlying cerebral plasticity. Coupled with noninvasive detection of its occurrence, such an understanding has huge potential to improve glioma therapy. The authors aimed to demonstrate the frequency of plastic reshaping, find clues to the patterns behind it, and prove that it can be recognized noninvasively using navigated transcranial magnetic stimulation (nTMS). METHODS The authors used nTMS to map cortical motor representation in 22 patients with gliomas affecting the precentral gyrus, preoperatively and 3-42 months postoperatively. Location changes of the primary motor area, defined as hotspots and map centers of gravity, were measured. RESULTS Spatial normalization and analysis of hotspots showed an average shift of 5.1 ± 0.9 mm (mean ± SEM) on the mediolateral axis, and 10.7 ± 1.6 mm on the anteroposterior axis. Map centers of gravity were found to have shifted by 4.6 ± 0.8 mm on the mediolateral, and 8.7 ± 1.5 mm on the anteroposterior axis. Motor-eloquent points tended to shift toward the tumor by 4.5 ± 3.6 mm if the lesion was anterior to the rolandic region and by 2.6 ± 3.3 mm if it was located posterior to the rolandic region. Overall, 9 of 16 (56%) patients with high-grade glioma and 3 of 6 (50%) patients with low-grade glioma showed a functional shift > 10 mm at the cortical level. CONCLUSIONS Despite the small size of this series, analysis of these data showed that cortical functional reorganization occurs quite frequently. Moreover, nTMS was shown to detect such plastic reorganization noninvasively.

  15. Resection of Navigated Transcranial Magnetic Stimulation-Positive Prerolandic Motor Areas Causes Permanent Impairment of Motor Function.

    Science.gov (United States)

    Moser, Tobias; Bulubas, Lucia; Sabih, Jamil; Conway, Neal; Wildschutz, Noémie; Sollmann, Nico; Meyer, Bernhard; Ringel, Florian; Krieg, Sandro M

    2017-07-01

    Navigated transcranial magnetic stimulation (nTMS) helps to determine the distribution of motor eloquent areas prior to brain surgery. Yet, the eloquence of primary motor areas frontal to the precentral gyrus identified via nTMS is unclear. To investigate the resection of nTMS-positive prerolandic motor areas and its correlation with postsurgical impairment of motor function. Forty-three patients with rolandic or prerolandic gliomas (WHO grade I-IV) underwent nTMS prior to surgery. Only patients without ischemia within the motor system in postoperative MRI diffusion sequences were enrolled. Based on the 3-dimensional fusion of preoperative nTMS motor mapping data with postsurgical MRI scans, we identified nTMS points that were resected in the infiltration zone of the tumor. We then classified the resected points according to the localization and latency of their motor evoked potentials. Surgery-related paresis was graded as transient (≤6 weeks) or permanent (>6 weeks). Out of 43, 31 patients (72%) showed nTMS-positive motor points in the prerolandic gyri. In general, 13 out of 43 patients (30%) underwent resection of nTMS points. Ten out of these patients showed postoperative paresis. There were 2 (15%) patients with a transient and 8 (62%) with a permanent surgery-related paresis. In 3 cases (23%), motor function remained unimpaired. After resection of nTMS-positive motor points, 62% of patients suffered from a new permanent paresis. Thus, even though they are located in the superior or middle frontal gyrus, these cortical areas must undergo intraoperative mapping. Copyright © 2017 by the Congress of Neurological Surgeons.

  16. Differential effect of conditioning sequences in coupling inhibitory/facilitatory repetitive transcranial magnetic stimulation for poststroke motor recovery.

    Science.gov (United States)

    Wang, Chih-Pin; Tsai, Po-Yi; Yang, Tsui Fen; Yang, Kuang-Yao; Wang, Chien-Chih

    2014-04-01

    While neuromodulation through unihemispheric repetitive transcranial magnetic stimulation (rTMS) has shown promise for the motor recovery of stroke patients, the effectiveness of the coupling of different rTMS protocols remains unclear. We aimed to test the long-term efficacy of this strategy with different applying sequences and to identify the electrophysiological correlates of motor improvements to the paretic hand. In our sham-controlled, double-blinded parallel study, 48 stroke patients (2-6 months poststroke) were randomly allocated to three groups. Group A underwent 20-session rTMS conditioning initiated with 10-session 1 Hz rTMS over the contralesional primary motor cortex (M1), followed by 10-session intermittent theta burst stimulation (iTBS) consequently over the ipsilesional M1; Group B underwent the same two paradigms but in reverse; and Group C received sham stimulation that was identical to Group A. We tested cortical excitability and motor assessments at the baseline, postpriming rTMS, postconsequent rTMS, and at 3-months follow-up. Group A manifested greater improvement than Group B in Fugl-Meyer Assessment (FMA), Wolf Motor Function testing (WMFT) score, and muscle strength (P = 0.001-0.02) post the priming rTMS. After the consequent rTMS, Group A continued to present a superior outcome than Group B in FMA (P = 0.015) and WMFT score (P = 0.008) with significant behavior-electrophysiological correlation. Conditioning the contralesional M1 prior to ipsilesional iTBS was found to be optimal for enhancing hand function, and this effect persisted for at least 3 months. Early modulation within 6 months poststroke rebalances interhemispheric competition and appears to be a feasible time window for rTMS intervention. © 2014 John Wiley & Sons Ltd.

  17. Differences in motor evoked potentials induced in rats by transcranial magnetic stimulation under two separate anesthetics: implications for plasticity studies

    Directory of Open Access Journals (Sweden)

    Matthew Sykes

    2016-10-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is primarily used in humans to change the state of corticospinal excitability. To assess the efficacy of different rTMS stimulation protocols, motor evoked potentials (MEPs are used as a readout due to their non-invasive nature. Stimulation of the motor cortex produces a response in a targeted muscle, and the amplitude of this twitch provides an indirect measure of the current state of the cortex. When applied to the motor cortex, rTMS can alter MEP amplitude, however results are variable between participants and across studies. In addition, the mechanisms underlying any change and its locus are poorly understood. In order to better understand these effects, MEPs have been investigated in vivo in animal models, primarily in rats. One major difference in protocols between rats and humans is the use of general anesthesia in animal experiments. Anesthetics are known to affect plasticity-like mechanisms and so may contaminate the effects of an rTMS protocol. In the present study, we explored the effect of anesthetic on MEP amplitude, recorded before and after intermittent theta burst stimulation (iTBS, a patterned rTMS protocol with reported facilitatory effects. MEPs were assessed in the brachioradialis muscle of the upper forelimb under two anesthetics: a xylazine/zoletil combination and urethane. We found MEPs could be induced under both anesthetics, with no differences in the resting motor threshold or the average baseline amplitudes. However, MEPs were highly variable between animals under both anesthetics, with the xylazine/zoletil combination showing higher variability and most prominently a rise in amplitude across the baseline recording period. Interestingly, application of iTBS did not facilitate MEP amplitude under either anesthetic condition. Although it is important to underpin human application of TMS with mechanistic examination of effects in animals, caution must be taken when

  18. A double-blind, randomized trial of deep repetitive transcranial magnetic stimulation (rTMS) for autism spectrum disorder.

    Science.gov (United States)

    Enticott, Peter G; Fitzgibbon, Bernadette M; Kennedy, Hayley A; Arnold, Sara L; Elliot, David; Peachey, Amy; Zangen, Abraham; Fitzgerald, Paul B

    2014-01-01

    Biomedical treatment options for autism spectrum disorder (ASD) are extremely limited. Repetitive transcranial magnetic stimulation (rTMS) is a safe and efficacious technique when targeting specific areas of cortical dysfunction in major depressive disorder, and a similar approach could yield therapeutic benefits in ASD, if applied to relevant cortical regions. The aim of this study was to examine whether deep rTMS to bilateral dorsomedial prefrontal cortex improves social relating in ASD. 28 adults diagnosed with either autistic disorder (high-functioning) or Asperger's disorder completed a prospective, double-blind, randomized, placebo-controlled design with 2 weeks of daily weekday treatment. This involved deep rTMS to bilateral dorsomedial prefrontal cortex (5 Hz, 10-s train duration, 20-s inter-train interval) for 15 min (1500 pulses per session) using a HAUT-Coil. The sham rTMS coil was encased in the same helmet of the active deep rTMS coil, but no effective field was delivered into the brain. Assessments were conducted before, after, and one month following treatment. Participants in the active condition showed a near significant reduction in self-reported social relating symptoms from pre-treatment to one month follow-up, and a significant reduction in social relating symptoms (relative to sham participants) for both post-treatment assessments. Those in the active condition also showed a reduction in self-oriented anxiety during difficult and emotional social situations from pre-treatment to one month follow-up. There were no changes for those in the sham condition. Deep rTMS to bilateral dorsomedial prefrontal cortex yielded a reduction in social relating impairment and socially-related anxiety. Further research in this area should employ extended rTMS protocols that approximate those used in depression in an attempt to replicate and amplify the clinical response. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. The impact of preoperative language mapping by repetitive navigated transcranial magnetic stimulation on the clinical course of brain tumor patients.

    Science.gov (United States)

    Sollmann, Nico; Ille, Sebastian; Hauck, Theresa; Maurer, Stefanie; Negwer, Chiara; Zimmer, Claus; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

    2015-04-11

    Language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) is used for resection planning in patients suffering from brain lesions within regions known to be involved in language function. Yet we also need data that show whether patients benefit clinically from preoperative rTMS for language mapping. We enrolled 25 patients with language eloquently located brain lesions undergoing preoperative rTMS language mapping (GROUP 1, 2011-2013), with the mapping results not being available for the surgeon, and we matched these patients with 25 subjects who also underwent preoperative rTMS (GROUP 2, 2013-2014), but the mapping results were taken into account during tumor resection. Additionally, cortical language maps were generated by analyzing preoperative rTMS and intraoperative direct cortical stimulation (DCS) data. Mean anterior-posterior (ap) craniotomy extents and overall craniotomy sizes were significantly smaller for the patients in GROUP 2 (Ap: p = 0.0117; overall size: p = 0.0373), and postoperative language deficits were found significantly more frequently for the patients in GROUP 1 (p = 0.0153), although the preoperative language status did not differ between groups (p = 0.7576). Additionally, there was a trend towards fewer unexpected tumor residuals, shorter surgery duration, less peri- or postoperative complications, shorter inpatient stay, and higher postoperative Karnofsky performance status scale (KPS) for the patients in GROUP 2. The present study provides a first hint that the clinical course of patients suffering from brain tumors might be improved by preoperative rTMS language mapping. However, a significant difference between both groups was only found for craniotomy extents and postoperative deficits, but not for other clinical parameters, which only showed a trend toward better results in GROUP 2. Therefore, multicenter trials with higher sample sizes are needed to further investigate the distinct impact of r

  20. Safety and tolerability of repetitive transcranial magnetic stimulation in patients with pathologic positive sensory phenomena: a review of literature

    Science.gov (United States)

    Muller, Paul A; Pascual-Leone, Alvaro; Rotenberg, Alexander

    2013-01-01

    BACKGROUND Repetitive transcranial magnetic stimulation (rTMS) is emerging as a valuable therapeutic and diagnostic tool. rTMS appears particularly promising for disorders characterized by positive sensory phenomena attributable to alterations in sensory cortex excitability. Among these are tinnitus, auditory and visual hallucinations, and pain syndromes. OBJECTIVE Despite studies addressing rTMS efficacy in suppression of positive sensory symptoms, the safety of stimulation of potentially hyperexcitable cortex has not been fully addressed. We performed a systematic literature review and metanalysis to describe the rTMS safety profile in these disorders. METHODS Using the PubMed database, we performed an English-language literature search from January 1985 to April 2011 to review all pertinent publications. Per study, we noted and listed pertinent details. From these data we also calculated a crude per-subject risk for each adverse event. RESULTS 106 publications (n = 1815 subjects) were identified with patients undergoing rTMS for pathologic positive sensory phenomena. Adverse events associated with rTMS were generally mild and occurred in 16.7% of subjects. Seizure was the most serious adverse event, and occurred in three patients with a 0.16% crude per-subject risk. The second most severe adverse event involved aggravation of sensory phenomena, occurring in 1.54%. CONCLUSIONS The published data suggest rTMS for the treatment or diagnosis of pathologic positive sensory phenomena appears to be a relatively safe and well-tolerated procedure. However, published data are lacking in systematic reporting of adverse events, and safety risks of rTMS in these patient populations will have to be addressed in future prospective trials. PMID:22322098

  1. Repetitive transcranial magnetic stimulation in cervical dystonia: effect of site and repetition in a randomized pilot trial.

    Directory of Open Access Journals (Sweden)

    Sarah Pirio Richardson

    Full Text Available Dystonia is characterized by abnormal posturing due to sustained muscle contraction, which leads to pain and significant disability. New therapeutic targets are needed in this disorder. The objective of this randomized, sham-controlled, blinded exploratory study is to identify a specific motor system target for non-invasive neuromodulation and to evaluate this target in terms of safety and tolerability in the cervical dystonia (CD population. Eight CD subjects were given 15-minute sessions of low-frequency (0.2 Hz repetitive transcranial magnetic stimulation (rTMS over the primary motor cortex (MC, dorsal premotor cortex (dPM, supplementary motor area (SMA, anterior cingulate cortex (ACC and a sham condition with each session separated by at least two days. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS score was rated in a blinded fashion immediately pre- and post-intervention. Secondary outcomes included physiology and tolerability ratings. The mean change in TWSTRS severity score by site was 0.25 ± 1.7 (ACC, -2.9 ± 3.4 (dPM, -3.0 ± 4.8 (MC, -0.5 ± 1.1 (SHAM, and -1.5 ± 3.2 (SMA with negative numbers indicating improvement in symptom control. TWSTRS scores decreased from Session 1 (15.1 ± 5.1 to Session 5 (11.0 ± 7.6. The treatment was tolerable and safe. Physiology data were acquired on 6 of 8 subjects and showed no change over time. These results suggest rTMS can modulate CD symptoms. Both dPM and MC are areas to be targeted in further rTMS studies. The improvement in TWSTRS scores over time with multiple rTMS sessions deserves further evaluation.

  2. The effect of anodal transcranial direct current stimulation over the primary motor or somatosensory cortices on somatosensory evoked magnetic fields.

    Science.gov (United States)

    Sugawara, Kazuhiro; Onishi, Hideaki; Yamashiro, Koya; Kojima, Sho; Miyaguchi, Shota; Kirimoto, Hikari; Tsubaki, Atsuhiro; Tamaki, Hiroyuki; Shirozu, Hiroshi; Kameyama, Shigeki

    2015-01-01

    The purpose of this study was to investigate the effect of anodal transcranial direct-current stimulation (tDCS) applied over the primary motor (M1) or the primary somatosensory (S1) cortices on somatosensory evoked magnetic fields (SEFs) following median nerve stimulation. Anodal tDCS was applied for 15min on the left motor or somatosensory cortices at 1mA. SEFs were recorded following right median nerve stimulation using a magnetoencephalography (MEG) system before and after the application of tDCS. SEFs was measured and compared before and after tDCS was applied over M1 or S1. The source strengths for the P35m and P60m increased after tDCS was applied over M1 and that for the P60m increased after tDCS was applied over S1. The mean equivalent current dipole (ECD) location for the P35m was located significantly anterior to that of the N20m, but only during post 1 (10-20min after tDCS was applied over M1). Our results indicated that the anodal tDCS applied over M1 affected the P35m and P60m sources on SEF components, while that applied over S1 influenced the P60m source. We demonstrated anodal tDCS applied over M1 or S1 can modulate somatosensory processing and components of SEFs, confirming the hypothesis for locally distinct generators of the P35m and P60m sources. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Randomized sham-controlled trial of repetitive transcranial magnetic stimulation in treatment-resistant obsessive-compulsive disorder.

    Science.gov (United States)

    Mantovani, Antonio; Simpson, Helen B; Fallon, Brian A; Rossi, Simone; Lisanby, Sarah H

    2010-03-01

    In open trials, 1-Hz repetitive transcranial magnetic stimulation (rTMS) to the supplementary motor area (SMA) improved symptoms and normalized cortical hyper-excitability of patients with obsessive-compulsive disorder (OCD). Here we present the results of a randomized sham-controlled double-blind study. Medication-resistant OCD patients (n=21) were assigned 4 wk either active or sham rTMS to the SMA bilaterally. rTMS parameters consisted of 1200 pulses/d, at 1 Hz and 100% of motor threshold (MT). Eighteen patients completed the study. Response to treatment was defined as a > or = 25% decrease on the Yale-Brown Obsessive Compulsive Scale (YBOCS). Non-responders to sham and responders to active or sham rTMS were offered four additional weeks of open active rTMS. After 4 wk, the response rate in the completer sample was 67% (6/9) with active and 22% (2/9) with sham rTMS. At 4 wk, patients receiving active rTMS showed on average a 25% reduction in the YBOCS compared to a 12% reduction in those receiving sham. In those who received 8-wk active rTMS, OCD symptoms improved from 28.2+/-5.8 to 14.5+/-3.6. In patients randomized to active rTMS, MT measures on the right hemisphere increased significantly over time. At the end of 4-wk rTMS the abnormal hemispheric laterality found in the group randomized to active rTMS normalized. The results of the first randomized sham-controlled trial of SMA stimulation in the treatment of resistant OCD support further investigation into the potential therapeutic applications of rTMS in this disabling condition.

  4. Transcranial magnetic stimulation: potential treatment for co-occurring alcohol, traumatic brain injury and posttraumatic stress disorders.

    Science.gov (United States)

    Herrold, Amy A; Kletzel, Sandra L; Harton, Brett C; Chambers, R Andrew; Jordan, Neil; Pape, Theresa Louise-Bender

    2014-10-01

    Alcohol use disorder (AUD), mild traumatic brain injury (mTBI), and posttraumatic stress disorder (PTSD) commonly co-occur (AUD + mTBI + PTSD). These conditions have overlapping symptoms which are, in part, reflective of overlapping neuropathology. These conditions become problematic because their co-occurrence can exacerbate symptoms. Therefore, treatments must be developed that are inclusive to all three conditions. Repetitive transcranial magnetic stimulation (rTMS) is non-invasive and may be an ideal treatment for co-occurring AUD + mTBI + PTSD. There is accumulating evidence on rTMS as a treatment for people with AUD, mTBI, and PTSD each alone. However, there are no published studies to date on rTMS as a treatment for co-occurring AUD + mTBI + PTSD. This review article advances the knowledge base for rTMS as a treatment for AUD + mTBI + PTSD. This review provides background information about these co-occurring conditions as well as rTMS. The existing literature on rTMS as a treatment for people with AUD, TBI, and PTSD each alone is reviewed. Finally, neurobiological findings in support of a theoretical model are discussed to inform TMS as a treatment for co-occurring AUD + mTBI + PTSD. The peer-reviewed literature was identified by targeted literature searches using PubMed and supplemented by cross-referencing the bibliographies of relevant review articles. The existing evidence on rTMS as a treatment for these conditions in isolation, coupled with the overlapping neuropathology and symptomology of these conditions, suggests that rTMS may be well suited for the treatment of these conditions together.

  5. Does a single session of theta-burst transcranial magnetic stimulation of inferior temporal cortex affect tinnitus perception?

    Directory of Open Access Journals (Sweden)

    Moser Tobias

    2009-05-01

    Full Text Available Abstract Background Cortical excitability changes as well as imbalances in excitatory and inhibitory circuits play a distinct pathophysiological role in chronic tinnitus. Repetitive transcranial magnetic stimulation (rTMS over the temporoparietal cortex was recently introduced to modulate tinnitus perception. In the current study, the effect of theta-burst stimulation (TBS, a novel rTMS paradigm was investigated in chronic tinnitus. Twenty patients with chronic tinnitus completed the study. Tinnitus severity and loudness were monitored using a tinnitus questionnaire (TQ and a visual analogue scale (VAS before each session. Patients received 600 pulses of continuous TBS (cTBS, intermittent TBS (iTBS and intermediate TBS (imTBS over left inferior temporal cortex with an intensity of 80% of the individual active or resting motor threshold. Changes in subjective tinnitus perception were measured with a numerical rating scale (NRS. Results TBS applied to inferior temporal cortex appeared to be safe. Although half of the patients reported a slight attenuation of tinnitus perception, group analysis resulted in no significant difference when comparing the three specific types of TBS. Converting the NRS into the VAS allowed us to compare the time-course of aftereffects. Only cTBS resulted in a significant short-lasting improvement of the symptoms. In addition there was no significant difference when comparing the responder and non-responder groups regarding their anamnestic and audiological data. The TQ score correlated significantly with the VAS, lower loudness indicating less tinnitus distress. Conclusion TBS does not offer a promising outcome for patients with tinnitus in the presented study.

  6. Repetitive transcranial magnetic stimulation once a week induces sustainable long-term relief of central poststroke pain.

    Science.gov (United States)

    Kobayashi, Masahito; Fujimaki, Takamitsu; Mihara, Ban; Ohira, Takayuki

    2015-06-01

    Central poststroke pain is a serious problem for some patients after stroke. Repetitive transcranial magnetic stimulation (rTMS) has been reported to relieve poststroke pain but its efficacy is still controversial. We tested the possibility that rTMS, when applied once a week, would induce sustainable relief of poststroke pain. Eighteen patients with central poststroke pain were included in this study. rTMS (10 trains of 10-sec 5 Hz-rTMS) was delivered over the primary motor cortex on the affected side. The rTMS session was repeated once a week for 12 weeks, and for six patients the intervention was continued for one year. The degree of the pain was assessed before each weekly rTMS session to evaluate sustainable effects. The effects of the rTMS reached a plateau at the eighth week. At the 12th week, the rTMS was effective in 61.1% of the patients; 5 of the 18 patients showed more than 70% reduction based on a visual analog scale, 6 patients showed 40-69% reduction, and 7 remained at a pain reduction level of less than 40%. When patients were divided into two groups with or without severe dysesthesia, it was found that eight patients with severe dysesthesia showed less pain relief than those without. In the six patients who continued rTMS for one year, the pain relief effects also were sustained. Although this was an open-label study without a control group, our findings suggest that rTMS of the primary motor cortex, when maintained once a week, could help to relieve poststroke pain. © 2015 International Neuromodulation Society.

  7. Effect of electroconvulsive therapy on cortical excitability in patients with major depression: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Chistyakov, Andrei V; Kaplan, Boris; Rubichek, Odil; Kreinin, Isabella; Koren, Dani; Hafner, Hava; Feinsod, Moshe; Klein, Ehud

    2005-02-01

    The antidepressant action of electro-convulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS) may be related to their ability to modulate cortical excitability. The aim of this study was to investigate changes in cortical excitability following ECT in patients with major depression (MD) and to compare therapeutic efficacy of ECT combined with rTMS to that of ECT alone. Twenty-two patients with MD were assigned to receive ECT and right prefrontal 1 Hz rTMS (n=12) or ECT with sham rTMS (n=10). ECT was given twice weekly and rTMS was applied on the remaining 4 days, throughout 3 weeks. The resting motor threshold (rMT) and motor evoked potential (MEP)/M-wave area ratio were evaluated before and 6 h after the first, third and sixth ECT session. The active motor threshold (aMT), intra-cortical inhibition (ICI) and intra-cortical facilitation (ICF) were measured at baseline and 24 h after the last ECT. There were no significant differences in the degree of clinical improvement and measures of cortical excitability in the ECT+active rTMS group as compared to the ECT+sham rTMS group. Marked clinical improvement observed in 19 out of the 22 patients was associated with a significant increase of the MEP/M-wave area ratio, decrease of the aMT and reduction of the ICI in the left hemisphere. The antidepressant effect of ECT was associated with an enhancement of left hemispheric excitability. rTMS did not add to the beneficial effect of ECT. However, the small sample size and the robust effect of ECT might have obscured a potential therapeutic effect of rTMS. Measures of cortical excitability may provide insight to our understanding of the mechanism of action of ECT and might be useful for the assessment of treatment response.

  8. Factors Associated With Upper Extremity Functional Recovery Following Low-Frequency Repetitive Transcranial Magnetic Stimulation in Stroke Patients.

    Science.gov (United States)

    Kim, Seo Young; Shin, Sung Bong; Lee, Seong Jae; Kim, Tae Uk; Hyun, Jung Keun

    2016-06-01

    To investigate the factors related to upper extremity functional improvement following inhibitory repetitive transcranial magnetic stimulation (rTMS) in stroke patients. Forty-one stroke patients received low-frequency rTMS over the contralesional hemisphere according to a standard protocol, in addition to conventional physical and occupational therapy. The rTMS-treated patients were divided into two groups according to their responsiveness to rTMS measured by the self-care score of the Korean version of Modified Barthel Index (K-MBI): responded group (n=19) and non-responded group (n=22). Forty-one age-matched stroke patients who had not received rTMS served as controls. Neurological, cognitive and functional assessments were performed before rTMS and 4 weeks after rTMS treatment. Among the rTMS-treated patients, the responded group was significantly younger than the non-responded group (51.6±10.5 years and 65.5±13.7 years, respectively; p=0.001). Four weeks after rTMS, the National Institutes of Health Stroke Scale, the Brunnstrom recovery stage and upper extremity muscle power scores were significantly more improved in the responded group than in the control group. Besides the self-care score, the mobility score of the K-MBI was also more improved in the responded group than in the non-responded group or controls. Age is the most obvious factor determining upper extremity functional responsiveness to low-frequency rTMS in stroke patients.

  9. Low-Frequency Repetitive Transcranial Magnetic Stimulation for Stroke-Induced Upper Limb Motor Deficit: A Meta-Analysis.

    Science.gov (United States)

    Zhang, Lan; Xing, Guoqiang; Shuai, Shiquan; Guo, Zhiwei; Chen, Huaping; McClure, Morgan A; Chen, Xiaojuan; Mu, Qiwen

    2017-01-01

    This meta-analysis aimed to evaluate the therapeutic potential of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional hemisphere on upper limb motor recovery and cortex plasticity after stroke. Databases of PubMed, Medline, ScienceDirect, Cochrane, and Embase were searched for randomized controlled trials published before Jun 31, 2017. The effect size was evaluated by using the standardized mean difference (SMD) and a 95% confidence interval (CI). Resting motor threshold (rMT) and motor-evoked potential (MEP) were also examined. Twenty-two studies of 1 Hz LF-rTMS over the contralesional hemisphere were included. Significant efficacy was found on finger flexibility (SMD = 0.75), hand strength (SMD = 0.49), and activity dexterity (SMD = 0.32), but not on body function (SMD = 0.29). The positive changes of rMT (SMD = 0.38 for the affected hemisphere and SMD = -0.83 for the unaffected hemisphere) and MEP (SMD = -1.00 for the affected hemisphere and SMD = 0.57 for the unaffected hemisphere) were also significant. LF-rTMS as an add-on therapy significantly improved upper limb functional recovery especially the hand after stroke, probably through rebalanced cortical excitability of both hemispheres. Future studies should determine if LF-rTMS alone or in conjunction with practice/training would be more effective. This trial is registered with unique identifier CRD42016042181.

  10. Hemispheric language dominance measured by repetitive navigated transcranial magnetic stimulation and postoperative course of language function in brain tumor patients.

    Science.gov (United States)

    Ille, Sebastian; Kulchytska, Nataliia; Sollmann, Nico; Wittig, Regina; Beurskens, Eva; Butenschoen, Vicki M; Ringel, Florian; Vajkoczy, Peter; Meyer, Bernhard; Picht, Thomas; Krieg, Sandro M

    2016-10-01

    The resection of left-sided perisylvian brain lesions harbors the risk of postoperative aphasia. Because it is known that language function can shift between hemispheres in brain tumor patients, the preoperative knowledge of the patient's language dominance could be helpful. We therefore investigated the hemispheric language dominance by repetitive navigated transcranial magnetic stimulation (rTMS) and surgery-related deficits of language function. We pooled the bicentric language mapping data of 80 patients undergoing the resection of left-sided perisylvian brain lesions in our two university neurosurgical departments. We calculated error rates (ERs; ER = errors per stimulations) for both hemispheres and defined the hemispheric dominance ratio (HDR) as the quotient of the left- and right-sided ER (HDR >1= left dominant; HDR language function was evaluated and correlated with the preoperative HDR. Only three of 80 patients (4%) presented with permanent surgery-related aphasia and 24 patients (30%) with transient surgery-related aphasia. The mean HDR (± standard deviation) of patients with new aphasia after five days was significantly higher (1.68±1.07) than the HDR of patients with no new language deficit (1.37±1.08) (p=0.0482). With a predefined cut-off value of 0.5 for HDR, we achieved a sensitivity for predicting new aphasia of 100%. A higher preoperative HDR significantly correlates with an increased risk for transient aphasia. Moreover, the intensive preoperative workup in this study led to a considerably low rate of permanent aphasia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Neurocognitive Effects of Repetitive Transcranial Magnetic Stimulation with a 2-Coil Device in Treatment-Resistant Major Depressive Disorder.

    Science.gov (United States)

    Kavanaugh, Brian C; Aaronson, Scott T; Clarke, Gregory N; Holtzheimer, Paul E; Johnson, Clark W; McDonald, William M; Schneider, M Bret; Carpenter, Linda L

    2018-04-02

    Neurocognitive dysfunction is an understudied and undertreated aspect of psychiatric research and treatment. There is emerging evidence to suggest that repetitive transcranial magnetic stimulation (rTMS) may possess neurocognition-enhancing capabilities. This study examined the neurocognitive data from a randomized, double-blind, sham-controlled trial of an investigational 2-coil rTMS device in antidepressant treatment or treatment-intolerant major depressive disorder patients. This device has the potential to stimulate deeper areas of the brain than the Food and Drug Administration-approved TMS devices, which primarily stimulate cortical brain areas and may therefore have different neurocognitive adverse effects. Patients received 20 daily rTMS treatments (10-Hz stimulation; either active or sham) with coil centers positioned over the left dorsolateral prefrontal cortex and dorsomedial prefrontal cortex. Neurocognitive safety was evaluated at baseline and within 72 hours of final treatment session with a computerized battery assessing aspects of attention and memory in 84 participants. There were no observed negative neurocognitive effects of the 2-coil rTMS device. A significant effect of active rTMS was observed on the quality of episodic memory. There were no observed effects for attention or working memory. Baseline quality of episodic memory predicted depression treatment response and remission, in that lower baseline episodic memory was associated with greater likelihood of depression response/remission. This was observed in logistic regression analyses controlling for treatment and baseline depressive symptoms. The 2-coil rTMS device is a cognitively safe treatment for treatment-resistant depression that may possess episodic memory-enhancing capabilities. Furthermore, baseline episodic memory may reflect an important predictor of subsequent depression treatment response/remission to rTMS.

  12. Repetitive transcranial magnetic stimulation regulates L-type Ca(2+) channel activity inhibited by early sevoflurane exposure.

    Science.gov (United States)

    Liu, Yang; Yang, Huiyun; Tang, Xiaohong; Bai, Wenwen; Wang, Guolin; Tian, Xin

    2016-09-01

    Sevoflurane might be harmful to the developing brain. Therefore, it is essential to reverse sevoflurane-induced brain injury. This study aimed to determine whether low-frequency repetitive transcranial magnetic stimulation (rTMS) can regulate L-type Ca(2+) channel activity, which is inhibited by early sevoflurane exposure. Rats were randomly divided into three groups: control, sevoflurane, and rTMS groups. A Whole-cell patch clamp technique was applied to record L-type Ca(2+) channel currents. The I-V curve, steady-state activation and inactivation curves were studied in rats of each group at different ages (1 week, 2 weeks, 3 weeks, 4 weeks and 5 weeks old). In the control group, L-type Ca(2+) channel current density significantly increased from week 2 to week 3. Compared with the control group, L-type Ca(2+) channel currents of rats in the sevoflurane group were significantly inhibited from week 1 to week 3. Activation curves of L-type Ca(2+) channel shifted significantly towards depolarization at week 1 and week 2. Moreover, steady-state inactivation curves shifted towards hyperpolarization from week 1 to week 3. Compared with the sevoflurane group, rTMS significantly increased L-type Ca(2+) channel currents at week 2 and week 3. Activation curves of L-type Ca(2+) channel significantly shifted towards hyperpolarization at week 2. Meanwhile, steady-state inactivation curves significantly shifted towards depolarization at week 2. The period between week 2 and week 3 is critical for the development of L-type Ca(2+) channels. Early sevoflurane exposure inhibits L-type Ca(2+) channel activity and rTMS can regulate L-type Ca(2+) channel activity inhibited by sevoflurane. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Transcranial magnetic stimulation follow-up study in early Parkinson's disease: A decline in compensation with disease progression?

    Science.gov (United States)

    Kojovic, Maja; Kassavetis, Panagiotis; Bologna, Matteo; Pareés, Isabel; Rubio-Agusti, Ignacio; Berardelli, Alfredo; Beraredelli, Alfredo; Edwards, Mark J; Rothwell, John C; Bhatia, Kailash P

    2015-07-01

    A number of neurophysiological abnormalities have been described in patients with Parkinson's disease, but very few longitudinal studies of how these change with disease progression have been reported. We describe measures of motor cortex inhibition and plasticity at 6 and 12 mo in 12 patients that we previously reported at initial diagnosis. Given the well-known interindividual variation in these measures, we were particularly concerned with the within-subject changes over time. Patients were assessed clinically, and transcranial magnetic stimulation (TMS) was used to measure motor cortical excitability, inhibition (short interval intracortical inhibition, cortical silent period), and plasticity (response to excitatory paired associative stimulation protocol) in both hemispheres. All measurements were performed 6 mo and 12 mo after the baseline experiments. Asymmetry in clinical motor symptoms was reflected in asymmetry of plasticity and inhibition. In the group as a whole, little change was seen in any of the parameters over 12 mo. However, analysis of within-individual data showed clear correlations between changes in clinical asymmetry and asymmetry of response to paired associative stimulation protocol and cortical silent period. Longitudinal changes in cortical silent period and response to paired associative stimulation protocol in Parkinson's disease reflect dynamic effects on motor cortex that are related to progression of motor signs. They are useful objective markers of early disease progression that could be used to detect effects of disease-modifying therapies. The decline in heightened plasticity that was present at disease onset may reflect failure of compensatory mechanisms that maintained function in the preclinical state. © 2015 International Parkinson and Movement Disorder Society.

  14. Transcranial magnetic stimulation of early visual cortex suppresses conscious representations in a dichotomous manner without gradually decreasing their precision.

    Science.gov (United States)

    Koivisto, Mika; Harjuniemi, Inari; Railo, Henry; Salminen-Vaparanta, Niina; Revonsuo, Antti

    2017-09-01

    Transcranial magnetic stimulation (TMS) of early visual cortex can suppresses visual perception at early stages of processing. The suppression can be measured both with objective forced-choice tasks and with subjective ratings of visual awareness, but there is lack of objective evidence on how and whether the TMS influences the quality of representations. Does TMS decrease the precision of representations in graded manner, or does it lead to dichotomous, "all-or-nothing" suppression. We resolved this question by using a continuous measure of the perceptual error: the observers had to perceive the orientation of a target (Landort-C) and to adjust the orientation of a probe to match that of the target. Mixture modeling was applied to estimate the probability of guess trials and the standard deviation of the non-guess trials. TMS delivered 60-150 ms after stimulus-onset influenced only the guessing rate, whereas the standard deviation (i.e., precision) was not affected. This suggests that TMS suppressed representations dichotomously without affecting their precision. The guessing probability correlated with subjective visibility ratings, suggesting that it measured visual awareness. In a control experiment, manipulation of the stimulus contrast affected the standard deviation of the errors, indicating that contrast has a gradual influence on the precision of representations. The findings suggest that TMS of early visual cortex suppresses perception in dichotomous manner by decreasing the signal-to-noise ratio by increasing the noise level, whereas reduction of the signal level (i.e., contrast) decreases the precision of representations. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Comparison of Transcranial Magnetic Stimulation and Electroneuronography Between Bell's Palsy and Ramsay Hunt Syndrome in Their Acute Stages

    Science.gov (United States)

    Hur, Dong Min; Lee, Young Hee; Kim, Sung Hoon; Park, Jung Mi; Kim, Ji Hyun; Yong, Sang Yeol; Shinn, Jong Mock; Oh, Kyung Joon

    2013-01-01

    Objective To examine the neurophysiologic status in patients with idiopathic facial nerve palsy (Bell's palsy) and Ramsay Hunt syndrome (herpes zoster oticus) within 7 days from onset of symptoms, by comparing the amplitude of compound muscle action potentials (CMAP) of facial muscles in electroneuronography (ENoG) and transcranial magnetic stimulation (TMS). Methods The facial nerve conduction study using ENoG and TMS was performed in 42 patients with Bell's palsy and 14 patients with Ramsay Hunt syndrome within 7 days from onset of symptoms. Denervation ratio was calculated as CMAP amplitude evoked by ENoG or TMS on the affected side as percentage of the amplitudes on the healthy side. The severity of the facial palsy was graded according to House-Brackmann facial grading scale (H-B FGS). Results In all subjects, the denervation ratio in TMS (71.53±18.38%) was significantly greater than the denervation ratio in ENoG (41.95±21.59%). The difference of denervation ratio between ENoG and TMS was significantly smaller in patients with Ramsay Hunt syndrome than in patients with Bell's palsy. The denervation ratio of ENoG or TMS did not correlated significantly with the H-B FGS. Conclusion In the electrophysiologic study for evaluation in patients with facial palsy within 7 days from onset of symptoms, ENoG and TMS are useful in gaining additional information about the neurophysiologic status of the facial nerve and may help to evaluate prognosis and set management plan. PMID:23525840

  16. The molecular evidence of neural plasticity induced by cerebellar repetitive transcranial magnetic stimulation in the rat brain: a preliminary report.

    Science.gov (United States)

    Lee, Seung Ah; Oh, Byung-Mo; Kim, Sang Jeong; Paik, Nam-Jong

    2014-07-11

    Cerebellar repetitive transcranial magnetic stimulation (rTMS) has been applied to treat several pathological conditions with insufficient evidence of molecular mechanism. Neural plasticity is proposed as one of mechanism. This study aimed to (1) confirm the feasibility of focal stimulation over cerebellar cortex and (2) investigate cerebellar rTMS effects on molecular changes associated with neural plasticity in the rat. For feasibility, six male Sprague-Dawley rats underwent (18)F-FDG positron emission tomography (PET) to confirm focal stimulation on the cerebellar cortex after rTMS. For molecular evidence, thirty rats underwent a single (N=15) or 10 sessions (N=15) of rTMS with low-, high-frequency, or sham stimulation. In cerebellar cortex, reverse-transcriptase polymerase chain reaction and western blotting were performed on mRNA and proteins associated with neural plasticity: metabotrophic glutamate receptor 1 (GluR1), 2-amino-5-methyl-4-isoxazole-propionatic acid (AMPA) receptor (GluR2) and protein kinase C (PKC). As a result, (18)F-FDG-PET showed an increase of glucose metabolism in the cerebellar cortex. The transcription of mGluR1 decreased following a single session of high-frequency rTMS. Synthesis of mGluR, PKC and GluR2 was reduced after rTMS, especially high frequency stimulation. It is suggested that rTMS could focus on the cerebellar cortex in the rat and induce neural plasticity associated with long-term depression. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate

    Science.gov (United States)

    van de Ven, Vincent G.; Tong, Frank; Sack, Alexander T.

    2017-01-01

    Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS) triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise. PMID:28384347

  18. Extended remediation of sleep deprived-induced working memory deficits using fMRI-guided transcranial magnetic stimulation.

    Science.gov (United States)

    Luber, Bruce; Steffener, Jason; Tucker, Adrienne; Habeck, Christian; Peterchev, Angel V; Deng, Zhi-De; Basner, Robert C; Stern, Yaakov; Lisanby, Sarah H

    2013-06-01

    We attempted to prevent the development of working memory (WM) impairments caused by sleep deprivation using fMRI-guided repetitive transcranial magnetic stimulation (rTMS). Novel aspects of our fMRI-guided rTMS paradigm included the use of sophisticated covariance methods to identify functional networks in imaging data, and the use of fMRI-targeted rTMS concurrent with task performance to modulate plasticity effects over a longer term. Between-groups mixed model. TMS, MRI, and sleep laboratory study. 27 subjects (13 receiving Active rTMS, and 14 Sham) completed the sleep deprivation protocol, with another 21 (10 Active, 11 Sham) non-sleep deprived subjects run in a second experiment. Our previous covariance analysis had identified a network, including occipital cortex, which demonstrated individual differences in resilience to the deleterious effects of sleep deprivation on WM performance. Five Hz rTMS was applied to left lateral occipital cortex while subjects performed a WM task during 4 sessions over the course of 2 days of total sleep deprivation. At the end of the sleep deprivation period, Sham sleep deprived subjects exhibited degraded performance in the WM task. In contrast, those receiving Active rTMS did not show the slowing and lapsing typical in sleep deprivation, and instead performed similarly to non- sleep deprived subjects. Importantly, the Active sleep deprivation group showed rTMS-induced facilitation of WM performance a full 18 hours after the last rTMS session. Over the course of sleep deprivation, these results indicate that rTMS applied concurrently with WM task performance affected neural circuitry involved in WM to prevent its full impact.

  19. Increase in cortical pyramidal cell excitability accompanies depression-like behavior in mice: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Sun, Peng; Wang, Furong; Wang, Li; Zhang, Yu; Yamamoto, Ryo; Sugai, Tokio; Zhang, Qing; Wang, Zhengda; Kato, Nobuo

    2011-11-09

    Clinical evidence suggests that cortical excitability is increased in depressives. We investigated its cellular basis in a mouse model of depression. In a modified version of forced swimming (FS), mice were initially forced to swim for 5 consecutive days and then were treated daily with repetitive transcranial magnetic stimulation (rTMS) or sham treatment for the following 4 weeks without swimming. On day 2 through day 5, the mice manifested depression-like behaviors. The next and last FS was performed 4 weeks later, which revealed a 4 week maintenance of depression-like behavior in the sham mice. In slices from the sham controls, excitability in cingulate cortex pyramidal cells was elevated in terms of membrane potential and frequencies of spikes evoked by current injection. Depolarized resting potential was shown to depend on suppression of large conductance calcium-activated potassium (BK) channels. This BK channel suppression was confirmed by measuring spike width, which depends on BK channels. Chronic rTMS treatment during the 4 week period significantly reduced the depression-like behavior. In slices obtained from the rTMS mice, normal excitability and BK channel activity were recovered. Expression of a scaffold protein Homer1a was reduced by the FS and reversed by rTMS in the cingulate cortex. Similar recovery in the same behavioral, electrophysiological, and biochemical features was observed after chronic imipramine treatment. The present study demonstrated that manifestation and disappearance of depression-like behavior are in parallel with increase and decrease in cortical neuronal excitability in mice and suggested that regulation of BK channels by Homer1a is involved in this parallelism.

  20. Motor Cortex Reorganization in Patients with Glioma Assessed by Repeated Navigated Transcranial Magnetic Stimulation-A Longitudinal Study.

    Science.gov (United States)

    Barz, Anne; Noack, Anika; Baumgarten, Peter; Seifert, Volker; Forster, Marie-Therese

    2018-04-01

    Evidence for cerebral reorganization after resection of low-grade glioma has mainly been obtained by serial intraoperative cerebral mapping. Noninvasively collected data on cortical plasticity in tumor patients over a surgery-free period are still scarce. The present study therefore aimed at evaluating motor cortex reorganization by navigated transcranial magnetic stimulation (nTMS) in patients after perirolandic glioma surgery. nTMS was performed preoperatively and postoperatively in 20 patients, separated by 26.1 ± 24.8 months. Further nTMS mapping was conducted in 14 patients, resulting in a total follow-up period of 46.3 ± 25.4 months. Centers of gravity (CoGs) were calculated for every muscle representation area, and Euclidian distances between CoGs over time were defined. Results were compared with data from 12 healthy individuals, who underwent motor cortex mapping by nTMS in 2 sessions. Preoperatively and postoperatively pooled CoGs from the area of the dominant abductor pollicis brevis muscle and of the nondominant leg area differed significantly compared with healthy individuals (P reorganization of all representation areas was observed in 3 patients, and a significant shift of hand representation areas was identified in further 3 patients. Complete functional recovery of postoperative motor deficits was exclusively associated with cortical reorganization. Despite the low potential of remodeling within the somatosensory region, long-term reorganization of cortical motor function can be observed. nTMS is best suited for a noninvasive evaluation of this reorganization. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. The impact of early visual cortex transcranial magnetic stimulation on visual working memory precision and guess rate.

    Science.gov (United States)

    Rademaker, Rosanne L; van de Ven, Vincent G; Tong, Frank; Sack, Alexander T

    2017-01-01

    Neuroimaging studies have demonstrated that activity patterns in early visual areas predict stimulus properties actively maintained in visual working memory. Yet, the mechanisms by which such information is represented remain largely unknown. In this study, observers remembered the orientations of 4 briefly presented gratings, one in each quadrant of the visual field. A 10Hz Transcranial Magnetic Stimulation (TMS) triplet was applied directly at stimulus offset, or midway through a 2-second delay, targeting early visual cortex corresponding retinotopically to a sample item in the lower hemifield. Memory for one of the four gratings was probed at random, and participants reported this orientation via method of adjustment. Recall errors were smaller when the visual field location targeted by TMS overlapped with that of the cued memory item, compared to errors for stimuli probed diagonally to TMS. This implied topographic storage of orientation information, and a memory-enhancing effect at the targeted location. Furthermore, early pulses impaired performance at all four locations, compared to late pulses. Next, response errors were fit empirically using a mixture model to characterize memory precision and guess rates. Memory was more precise for items proximal to the pulse location, irrespective of pulse timing. Guesses were more probable with early TMS pulses, regardless of stimulus location. Thus, while TMS administered at the offset of the stimulus array might disrupt early-phase consolidation in a non-topographic manner, TMS also boosts the precise representation of an item at its targeted retinotopic location, possibly by increasing attentional resources or by injecting a beneficial amount of noise.

  2. The effects of transcranial magnetic stimulation over the dorsolateral prefrontal cortex on suppression of habitual counting during random number generation.

    Science.gov (United States)

    Jahanshahi, M; Profice, P; Brown, R G; Ridding, M C; Dirnberger, G; Rothwell, J C

    1998-08-01

    Random number generation is an attention-demanding task that engages working memory and executive processes. Random number generation requires holding information 'on line', suppression of habitual counting, internally driven response generation and monitoring of responses. Evidence from PET studies suggests that the dorsolateral prefrontal cortex (DLPFC) is involved in the generation of random responses. We examined the effects of short trains of transcranial magnetic stimulation (TMS) over the left or right DLPFC or medial frontal cortex on random number generation in healthy normal participants. As in previous evidence, in control trials without stimulation participants performed poorly on the random number generation task, showing repetition avoidance and a tendency to count. Brief disruption of processing with TMS over the left DLPFC changed the balance of the individuals' counting bias, increasing the most habitual counting in ones and reducing the lower probability response of counting in twos. This differential effect of TMS over the left DLPFC on the balance of the subject's counting bias was not obtained with TMS over the right DLPFC or the medial frontal cortex. The results suggest that, with disruption of the left DLPFC with TMS, habitual counting in ones that has previously been suppressed is released from inhibition. From these findings a network modulation model of random number generation is proposed, whereby suppression of habitual responses is achieved through the modulatory influence of the left DLPFC over a number-associative network in the superior temporal cortex. To allow emergence of appropriate random responses, the left DLPFC inhibits the superior temporal cortex to prevent spreading activation and habitual counting in ones.

  3. Effectiveness of repetitive transcranial magnetic stimulation (rTMS) after acute stroke: A one-year longitudinal randomized trial.

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    Guan, Yu-Zhou; Li, Jing; Zhang, Xue-Wei; Wu, Shuang; Du, Hua; Cui, Li-Ying; Zhang, Wei-Hong

    2017-12-01

    To evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) on motor recovery after stroke using a prospective, double-blind, randomized, sham-controlled study. Patients with unilateral subcortical infarction in the middle cerebral artery territory within 1 week after onset were enrolled. The patients were randomly divided into an rTMS treatment group and a sham group. We performed high-frequency rTMS or sham rTMS on the two groups. Motor functional scores were assessed pre- and post-rTMS/sham rTMS and at 1 month, 3 months, 6 months, and 1 year after stroke onset. The scores included the National Institutes of Health Stroke Scale (NIHSS), Barthel Index (BI), Fugl-Meyer Assessment Upper Limb/Lower Limb (FMA-UL/LL), modified Rank Score (mRS), and the resting motor threshold (RMT) of the hemiplegic limb. At baseline, no significant differences were found between the two groups for motor functional scores. On the second day after rTMS treatment, score improvements of the NIHSS, BI, FMA-UL in the real treatment group were more significant than those in the sham group. In addition, similar results were obtained at 1 month. However, at 3 months, 6 months, and 1 year after onset, no significant differences in improvement were observed between the two groups, except for the FMA-UL score improvement. rTMS facilitates motor recovery of acute stroke patients, and the effect can last to 1 month, except the function improvement on upper extremities could last for 1 year. A single course of rTMS in the acute stage may induce the improvement of upper extremities function lasted for 1 year. © 2017 John Wiley & Sons Ltd.

  4. Improvements in hand function in adults with chronic tetraplegia following a multiday 10-Hz repetitive transcranial magnetic stimulation intervention combined with repetitive task practice.

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    Gomes-Osman, Joyce; Field-Fote, Edelle C

    2015-01-01

    Evidence suggests that the use of stimulation to increase corticomotor excitability improves hand function in persons with cervical spinal cord injury. We assessed effects of a multiday application of 10-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the corticomotor hand area combined with repetitive task practice (RTP) in participants with tetraplegia and neurologically healthy participants. Using a double-blind, randomized, crossover design, 11 participants with chronic tetraplegia and 10 neurologically healthy participants received 3 sessions of 10-Hz rTMS+RTP and 3 sessions of sham-rTMS+RTP to the corticomotor hand region controlling the weaker hand. Repetitive transcranial magnetic stimulation was interleaved with RTP of a skilled motor task between pulse trains. Hand function (Jebsen-Taylor Hand Function Test, pinch, and grasp strength) and corticomotor excitability (amplitude of motor-evoked potential) were assessed before and after the rTMS+RTP and sham-rTMS+RTP phases. We assessed significance, using paired t tests on pre-post differences, and effect sizes, using the standardized response mean. RTMS+RTP was associated with larger effect sizes compared with sham-rTMS+RTP for improvement in Jebsen-Taylor Hand Function Test for both the trained hand (standardized response mean = 0.85 and 0.42, respectively) and non-trained hand (0.55 and 0.31, respectively), and for grasp strength of the trained hand in the group with cervical spinal cord injury (0.67 and 0.39, respectively) alone. Effect sizes for all other measures were small and there were no statistical between-condition differences in the outcomes assessed. Repetitive transcranial magnetic stimulation may be a valuable adjunct to RTP for improving hand function in persons with tetraplegia. Higher stimulation dose (frequency, intensity, and the number of sessions) may be associated with larger effects. (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A82) for more

  5. The development and modelling of devices and paradigms for transcranial magnetic stimulation.

    Science.gov (United States)

    Goetz, Stefan M; Deng, Zhi-De

    2017-04-01

    Magnetic stimulation is a non-invasive neurostimulation technique that can evoke action potentials and modulate neural circuits through induced electric fields. Biophysical models of magnetic stimulation have become a major driver for technological developments and the understanding of the mechanisms of magnetic neurostimulation and neuromodulation. Major technological developments involve stimulation coils with different spatial characteristics and pulse sources to control the pulse waveform. While early technological developments were the result of manual design and invention processes, there is a trend in both stimulation coil and pulse source design to mathematically optimize parameters with the help of computational models. To date, macroscopically highly realistic spatial models of the brain, as well as peripheral targets, and user-friendly software packages enable researchers and practitioners to simulate the treatment-specific and induced electric field distribution in the brains of individual subjects and patients. Neuron models further introduce the microscopic level of neural activation to understand the influence of activation dynamics in response to different pulse shapes. A number of models that were designed for online calibration to extract otherwise covert information and biomarkers from the neural system recently form a third branch of modelling.

  6. The development and modeling of devices and paradigms for transcranial magnetic stimulation

    Science.gov (United States)

    Goetz, Stefan M.; Deng, Zhi-De

    2017-01-01

    Magnetic stimulation is a noninvasive neurostimulation technique that can evoke action potentials and modulate neural circuits through induced electric fields. Biophysical models of magnetic stimulation have become a major driver for technological developments and the understanding of the mechanisms of magnetic neurostimulation and neuromodulation. Major technological developments involve stimulation coils with different spatial characteristics and pulse sources to control the pulse waveform. While early technological developments were the result of manual design and invention processes, there is a trend in both stimulation coil and pulse source design to mathematically optimize parameters with the help of computational models. To date, macroscopically highly realistic spatial models of the brain as well as peripheral targets, and user-friendly software packages enable researchers and practitioners to simulate the treatment-specific and induced electric field distribution in the brains of individual subjects and patients. Neuron models further introduce the microscopic level of neural activation to understand the influence of activation dynamics in response to different pulse shapes. A number of models that were designed for online calibration to extract otherwise covert information and biomarkers from the neural system recently form a third branch of modeling. PMID:28443696

  7. Associations between clinical outcome and navigated transcranial magnetic stimulation characteristics in patients with motor-eloquent brain lesions: a combined navigated transcranial magnetic stimulation-diffusion tensor imaging fiber tracking approach.

    Science.gov (United States)

    Sollmann, Nico; Wildschuetz, Noémie; Kelm, Anna; Conway, Neal; Moser, Tobias; Bulubas, Lucia; Kirschke, Jan S; Meyer, Bernhard; Krieg, Sandro M

    2018-03-01

    OBJECTIVE Navigated transcranial magnetic stimulation (nTMS) and diffusion tensor imaging fiber tracking (DTI FT) based on nTMS data are increasingly used for preoperative planning and resection guidance in patients suffering from motor-eloquent brain tumors. The present study explores whether nTMS-based DTI FT can also be used for individual preoperative risk assessment regarding surgery-related motor impairment. METHODS Data derived from preoperative nTMS motor mapping and subsequent nTMS-based tractography in 86 patients were analyzed. All patients suffered from high-grade glioma (HGG), low-grade glioma (LGG), or intracranial metastasis (MET). In this context, nTMS-based DTI FT of the corticospinal tract (CST) was performed at a range of fractional anisotropy (FA) levels based on an individualized FA threshold ([FAT]; tracking with 50%, 75%, and 100% FAT), which was defined as the highest FA value allowing for visualization of fibers (100% FAT). Minimum lesion-to-CST distances were measured, and fiber numbers of the reconstructed CST were assessed. These data were then correlated with the preoperative, postoperative, and follow-up status of motor function and the resting motor threshold (rMT). RESULTS At certain FA levels, a statistically significant difference in lesion-to-CST distances was observed between patients with HGG who had no impairment and those who developed surgery-related transient or permanent motor deficits (75% FAT: p = 0.0149; 100% FAT: p = 0.0233). In this context, no patient with a lesion-to-CST distance ≥ 12 mm suffered from any new surgery-related permanent paresis (50% FAT and 75% FAT). Furthermore, comparatively strong negative correlations were observed between the rMT and lesion-to-CST distances of patients with surgery-related transient paresis (Spearman correlation coefficient [r s ]; 50% FAT: r s = -0.8660; 75% FAT: r s = -0.8660) or surgery-related permanent paresis (50% FAT: r s = -0.7656; 75% FAT: r s = -0.6763). CONCLUSIONS

  8. Effects of repetitive transcranial magnetic stimulation on motor recovery and motor cortex excitability in patients with stroke: a randomized controlled trial.

    Science.gov (United States)

    Du, J; Tian, L; Liu, W; Hu, J; Xu, G; Ma, M; Fan, X; Ye, R; Jiang, Y; Yin, Q; Zhu, W; Xiong, Y; Yang, F; Liu, X

    2016-11-01

    Repetitive transcranial magnetic stimulation (rTMS) changes the excitability of the motor cortex and thereby has the potential to enhance motor recovery after stroke. This randomized, sham-controlled, double-blind study was to compare the effects of high-frequency versus low-frequency rTMS on motor recovery during the early phase of stroke and to identify the neurophysiological correlates of motor improvements. A total of 69 first-ever ischemic stroke patients with motor deficits were randomly allocated to receive five daily sessions of 3-Hz ipsilesional rTMS, 1-Hz contralesional rTMS or sham rTMS in addition to standard physical therapy. Outcome measures included motor deficits, neurological scores and cortical excitability, which were assessed at baseline, after the intervention and at 3-month follow-up. The rTMS groups manifested greater motor improvements than the control group, which were sustained for at least 3 months after the end of the treatment sessions. 1-Hz rTMS over the unaffected hemisphere produced more profound effects than 3-Hz rTMS in facilitating upper limb motor performance. There was a significant correlation between motor function improvement and motor cortex excitability change in the affected hemisphere. Repetitive transcranial magnetic stimulation is a beneficial neurorehabilitative strategy for enhancing motor recovery in the acute and subacute phase after stroke. © 2016 EAN.

  9. Comparison of the Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation with That of Theta Burst Stimulation on Upper Limb Motor Function in Poststroke Patients.

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    Kondo, Takahiro; Yamada, Naoki; Momosaki, Ryo; Shimizu, Masato; Abo, Masahiro

    2017-01-01

    The purpose of this study was to evaluate the difference between the therapeutic effect of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) and that of continuous theta burst stimulation (cTBS), when each is combined with intensive occupational therapy (OT), in poststroke patients with upper limb hemiparesis. The study subjects were 103 poststroke patients with upper limb hemiparesis, who were divided into two groups: the LF-rTMS group ( n = 71) and the cTBS group (three pulse bursts at 50 Hz) ( n = 32). Each subject received 12 sessions of repetitive transcranial magnetic stimulation of 2,400 pulses applied to the nonlesional hemisphere and 240-min intensive OT (two 60-min one-to-one training sessions and two 60-min self-training exercises) daily for 15 days. Motor function was evaluated using the Fugl-Meyer Assessment (FMA) and the performance time of the Wolf motor function test (WMFT) was determined on the days of admission and discharge. Both groups showed a significant increase in the FMA score and a short log performance time of the WMFT ( p < 0.001), but the increase in the FMA score was higher in the LF-rTMS group than the cTBS group ( p < 0.05). We recommend the use of 2400 pulses of LF-rTMS/OT for 2 weeks as treatment for hemiparetic patients.

  10. Presurgical mapping with functional MRI. Comparative study with transcranial magnetic stimulation and intraoperative mapping

    Energy Technology Data Exchange (ETDEWEB)

    Kaminogo, Makio; Morikawa, Minoru; Ishimaru, Hideki; Ochi, Makoto; Onizuka, Masanori; Shirakawa, Yasushi; Takahashi, Haruki; Shibata, Shobu [Nagasaki Univ. (Japan). School of Medicine

    1999-05-01

    The thumb movement was evoked by transcranical magnetic stimulation (TCS) for the mapping of the motor cortex. After the placement of the marker determined by TCS on the scalp, fMRI under motor tasks consisting of repetitive grasping was performed. For motor cortex activation, an axial oblique plane to maximize gray matter sampling in the rolandic cortex was employed in order to compare these different mapping techniques more precisely. Sixteen patients with brain tumors were included in this study. In nine patients, fMRI disclosed activation in one restricted gyrus or in the localized area around one restricted sulcus. Of these nine patients, preoperative TCS mapping corresponded closely with fMRI in six, while in the remaining three, the TCS marker fell between 1 and 2 cm apart from the fMRI-activated area. However, in these three patients, intraoperative electrocortical stimulation corresponded with the preoperative mapping with fMRI. In six patients, contiguous two gyri were activated by motor tasks. The TCS marker was disclosed on one of the two activated gyri. Of these six patients, the position of the TCS marker and fMRI-activated site corresponded with each other in four cases. They were found on the same gyrus but there was 1.0-2.0 cm distance between them in two cases. Intraoperative somatosensory evoked potential was monitored in two of these six cases. They corresponded well with the mapping by fMRI and TCS together. In only one patient, no significant activation area was obtained by fMRI because of excessive head motion during motor tasks. The TCS maker in this patients was identical with intraoperative electro-cortical stimulation mapping. (K.H.)

  11. Effects of 10 Hz Repetitive Transcranial Magnetic Stimulation of the Left Dorsolateral Prefrontal Cortex in Disorders of Consciousness

    Directory of Open Access Journals (Sweden)

    Xiaoyu Xia

    2017-05-01

    Full Text Available BackgroundWhile repetitive transcranial magnetic stimulation (rTMS has been applied in treatment of patients with disorders of consciousness (DOC, a standardized stimulation protocol has not been proposed, and its therapeutic effects are inconsistently documented.ObjectivesTo assess the efficacy of rTMS in improving consciousness in patients with persistent minimally conscious state (MCS or unresponsive wakefulness syndrome (UWS, previously known as vegetative state (VS.MethodA prospective single-blinded study, with selected subjects, was carried out. In total, 16 patients (5 MCS and 11 VS/UWS with chronic DOC were included. All patients received active 10 Hz rTMS at the left dorsolateral prefrontal cortex (DLPFC, at one session per day, for 20 consecutive days. A single daily session of stimulation consisted of 1,000 pulses (10 s of 10 Hz trains; repeated 10 times with an inter-train interval of 60 s; and 11 min and 40 s for total session. The main outcome measures were changes in the total score on the JFK Coma Recovery Scale-Revised (CRS-R scale. Additional measures were the impressions of caregivers after the conclusion of the interventions, which were assessed using the Clinical Global Impression-Improvement (CGI-I scale.ResultsThe CRS-R scores were increased in all 5 MCS patients and 4 of 11 VS/UWS patients, while a significant enhancement of CRS-R scores was observed compared to the baseline in all participants (p = 0.007. However, the improvement was more notable in MCS patients (p = 0.042 than their VS/UWS counterparts (p = 0.066. Based on the CGI-I scores, two patients improved considerably, two improved, six minimally improved, six experienced no change, and none deteriorated. Good concordance was seen between the CGI-I result and the increases in CRS-R scores.ConclusionTreatment of 10 Hz multisession rTMS applied to the left DLPFC is promising for the rehabilitation of DOC patients, especially those in MCS

  12. Comprehensive Survey on Improved Focality and Penetration Depth of Transcranial Magnetic Stimulation Employing Multi-Coil Arrays

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    Xile Wei

    2017-11-01

    Full Text Available Multi-coil arrays applied in transcranial magnetic stimulation (TMS are proposed to accurately stimulate brain tissues and modulate neural activities by an induced electric field (EF. Composed of numerous independently driven coils, a multi-coil array has alternative energizing strategies to evoke EFs targeting at different cerebral regions. To improve the locating resolution and the stimulating focality, we need to fully understand the variation properties of induced EFs and the quantitative control method of the spatial arrangement of activating coils, both of which unfortunately are still unclear. In this paper, a comprehensive analysis of EF properties was performed based on multi-coil arrays. Four types of planar multi-coil arrays were used to study the relationship between the spatial distribution of EFs and the structure of stimuli coils. By changing coil-driven strategies in a basic 16-coil array, we find that an EF induced by compactly distributed coils decays faster than that induced by dispersedly distributed coils, but the former has an advantage over the latter in terms of the activated brain volume. Simulation results also indicate that the attenuation rate of an EF induced by the 36-coil dense array is 3 times and 1.5 times greater than those induced by the 9-coil array and the 16-coil array, respectively. The EF evoked by the 36-coil dispense array has the slowest decay rate. This result demonstrates that larger multi-coil arrays, compared to smaller ones, activate deeper brain tissues at the expense of decreased focality. A further study on activating a specific field of a prescribed shape and size was conducted based on EF variation. Accurate target location was achieved with a 64-coil array 18 mm in diameter. A comparison between the figure-8 coil, the planar array, and the cap-formed array was made and demonstrates an improvement of multi-coil configurations in the penetration depth and the focality. These findings suggest

  13. Navigated transcranial magnetic stimulation for glioma removal: prognostic value in motor function recovery from postsurgical neurological deficits.

    Science.gov (United States)

    Takakura, Tomokazu; Muragaki, Yoshihiro; Tamura, Manabu; Maruyama, Takashi; Nitta, Masayuki; Niki, Chiharu; Kawamata, Takakazu

    2017-10-01

    OBJECTIVE The aim of the present study was to evaluate the usefulness of navigated transcranial magnetic stimulation (nTMS) as a prognostic predictor for upper-extremity motor functional recovery from postsurgical neurological deficits. METHODS Preoperative and postoperative nTMS studies were prospectively applied in 14 patients (mean age 39 ± 12 years) who had intraparenchymal brain neoplasms located within or adjacent to the motor eloquent area in the cerebral hemisphere. Mapping by nTMS was done 3 times, i.e., before surgery, and 1 week and 3 weeks after surgery. To assess the response induced by nTMS, motor evoked potential (nTMS-MEP) was recorded using a surface electromyography electrode attached to the abductor pollicis brevis (APB). The cortical locations that elicited the largest electromyography response by nTMS were defined as hotspots. Hotspots for APB were confirmed as positive responsive sites by direct electrical stimulation (DES) during awake craniotomy. The distances between hotspots and lesions (D HS-L ) were measured. Postoperative neurological deficits were assessed by manual muscle test and dynamometer. To validate the prognostic value of nTMS in recovery from upper-extremity paresis, the following were investigated: 1) the correlation between D HS-L and the serial grip strength change, and 2) the correlation between positive nTMS-MEP at 1 week after surgery and the serial grip strength change. RESULTS From the presurgical nTMS study, MEPs from targeted muscles were identified in 13 cases from affected hemispheres. In one case, MEP was not evoked due to a huge tumor. Among 9 cases from which intraoperative DES mapping for hand motor area was available, hotspots for APB identified by nTMS were concordant with DES-positive sites. Compared with the adjacent group (D HS-L motor recovery at 1 week, 3 weeks, and 3 months after surgery (r = 0.87, 0.88, and 0.77, respectively). CONCLUSIONS Navigated TMS is a useful tool for identifying motor eloquent

  14. Neurotransmitters behind pain relief with transcranial magnetic stimulation - positron emission tomography evidence for release of endogenous opioids.

    Science.gov (United States)

    Lamusuo, S; Hirvonen, J; Lindholm, P; Martikainen, I K; Hagelberg, N; Parkkola, R; Taiminen, T; Hietala, J; Helin, S; Virtanen, A; Pertovaara, A; Jääskeläinen, S K

    2017-10-01

    Repetitive transcranial magnetic stimulation (rTMS) at M1/S1 cortex has been shown to alleviate neuropathic pain. To investigate the possible neurobiological correlates of cortical neurostimulation for the pain relief. We studied the effects of M1/S1 rTMS on nociception, brain dopamine D2 and μ-opioid receptors using a randomized, sham-controlled, double-blinded crossover study design and 3D-positron emission tomography (PET). Ten healthy subjects underwent active and sham rTMS treatments to the right M1/S1 cortex with E-field navigated device. Dopamine D2 and μ-receptor availabilities were assessed with PET radiotracers [ 11 C]raclopride and [ 11 C]carfentanil after each rTMS treatment. Thermal quantitative sensory testing (QST), contact heat evoked potential (CHEP) and blink reflex (BR) recordings were performed between the PET scans. μ-Opioid receptor availability was lower after active than sham rTMS (P ≤ 0.0001) suggested release of endogenous opioids in the right ventral striatum, medial orbitofrontal, prefrontal and anterior cingulate cortices, and left insula, superior temporal gyrus, dorsolateral prefrontal cortex and precentral gyrus. There were no differences in striatal dopamine D2 receptor availability between active and sham rTMS, consistent with lack of long-lasting measurable dopamine release. Active rTMS potentiated the dopamine-regulated habituation of the BR compared to sham (P = 0.02). Thermal QST and CHEP remained unchanged after active rTMS. rTMS given to M1/S1 activates the endogenous opioid system in a wide brain network associated with processing of pain and other salient stimuli. Direct enhancement of top-down opioid-mediated inhibition may partly explain the clinical analgesic effects of rTMS. Neurobiological correlates of rTMS for the pain relief are unclear. rTMS on M1/S1 with 11 C-carfentanyl-PET activates endogenous opioids. Thermal and heat pain thresholds remain unchanged. rTMS induces top-down opioid-mediated inhibition

  15. Management of Chronic Tinnitus and Insomnia with Repetitive Transcranial Magnetic Stimulation and Cognitive Behavioral Therapy – a Combined Approach

    Directory of Open Access Journals (Sweden)

    Kneginja Richter

    2017-04-01

    Full Text Available It has been estimated that up to 80% of people will experience symptoms of tinnitus over the courses of their lives, with rates of comorbid sleeping problems ranging from 50 to 77%. Because of a potential connection between tinnitus and sleep disorders as well as high rates of comorbid psychiatric disorders, interdisciplinary approaches to treatment seem to be the most efficient option. In this study, we present the case of a 53-year-old male patient, who started to experience symptoms of tinnitus at the age of 49, most likely caused by work-related stress. Over the course of his illness, the patient developed comorbid insomnia. He consulted us for treatment of both conditions and we developed a treatment plan with ten sessions of repetitive transcranial magnetic stimulation (rTMS followed by 10 sessions of cognitive behavioral therapy (CBT. We used the Tinnitus Fragebogen (TF to assess the severity of the tinnitus, the Beck Depression Inventory (BDI-II for depressive symptoms, and the WHO Well-being Index (WHO-5 for subjective well-being. Improvements could be achieved with regard to both diagnoses and the patient went from severe (48 to clinically negligible (12 TF scores, from minimal (BDI-II score 10 to no (0 depressive symptoms, and from just above critical (WHO-5 percentile 52 to above average (84 well-being. The combination of technological and psychological approaches to treat tinnitus and insomnia thus proved successful in this case. One may therefore conclude that rTMS may be considered an effective first therapeutic step for tinnitus treatment prior to CBT. To our knowledge this is the first published case in which rTMS and CBT were combined for tinnitus therapy. The approach proved successful since it led to a considerable increase in well-being and everyday functioning. To gauge the effect on a more general level, large-scale studies are still needed to cancel out potential placebo effects. Likewise, the importance of the order of

  16. Acoustic evaluation of short-term effects of repetitive transcranial magnetic stimulation on motor aspects of speech in Parkinson's disease.

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    Eliasova, I; Mekyska, J; Kostalova, M; Marecek, R; Smekal, Z; Rektorova, I

    2013-04-01

    Hypokinetic dysarthria in Parkinson's disease (PD) can be characterized by monotony of pitch and loudness, reduced stress, variable rate, imprecise consonants, and a breathy and harsh voice. Using acoustic analysis, we studied the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) applied over the primary orofacial sensorimotor area (SM1) and the left dorsolateral prefrontal cortex (DLPFC) on motor aspects of voiced speech in PD. Twelve non-depressed and non-demented men with PD (mean age 64.58 ± 8.04 years, mean PD duration 10.75 ± 7.48 years) and 21 healthy age-matched men (a control group, mean age 64 ± 8.55 years) participated in the speech study. The PD patients underwent two sessions of 10 Hz rTMS over the dominant hemisphere with 2,250 stimuli/day in a random order: (1) over the SM1; (2) over the left DLPFC in the "on" motor state. Speech examination comprised the perceptual rating of global speech performance and an acoustic analysis based upon a standardized speech task. The Mann-Whitney U test was used to compare acoustic speech variables between controls and PD patients. The Wilcoxon test was used to compare data prior to and after each stimulation in the PD group. rTMS applied over the left SM1 was associated with a significant increase in harmonic-to-noise ratio and net speech rate in the sentence tasks. With respect to the vowel task results, increased median values and range of Teager-Kaiser energy operator, increased vowel space area, and significant jitter decrease were observed after the left SM1 stimulation. rTMS over the left DLPFC did not induce any significant effects. The positive results of acoustic analysis were not reflected in a subjective rating of speech performance quality as assessed by a speech therapist. Our pilot results indicate that one session of rTMS applied over the SM1 may lead to measurable improvement in voice quality and intensity and an increase in speech rate and tongue movements

  17. Magnetic Resonance Imaging-Guided, Open-Label, High-Frequency Repetitive Transcranial Magnetic Stimulation for Adolescents with Major Depressive Disorder.

    Science.gov (United States)

    Wall, Christopher A; Croarkin, Paul E; Maroney-Smith, Mandie J; Haugen, Laura M; Baruth, Joshua M; Frye, Mark A; Sampson, Shirlene M; Port, John D

    2016-09-01

    Preliminary studies suggest that repetitive transcranial magnetic stimulation (rTMS) may be an effective and tolerable intervention for adolescents with treatment-resistant depression. There is limited rationale to inform coil placement for rTMS dosing in this population. We sought to examine and compare three localization techniques for coil placement in the context of an open-label trial of high-frequency rTMS for adolescents with treatment-resistant depression. Ten adolescents with treatment-resistant depression were enrolled in an open-label trial of high-frequency rTMS. Participants were offered 30 rTMS sessions (10 Hz, 120% motor threshold, left 3000 pulses applied to the dorsolateral prefrontal cortex) over 6-8 weeks. Coil placement for treatment was MRI guided. The scalp location for treatment was compared with the locations identified with standard 5 cm rule and Beam F3 methods. Seven adolescents completed 30 rTMS sessions. No safety or tolerability concerns were identified. Depression severity as assessed with the Children's Depression Rating Scale Revised improved from baseline to treatment 10, treatment 20, and treatment 30. Gains in depressive symptom improvement were maintained at 6 month follow-up visits. An MRI-guided approach for coil localization was feasible and efficient. Our results suggest that the 5 cm rule, Beam F3, and the MRI-guided localization approaches provided variable scalp targets for rTMS treatment. Open-label, high-frequency rTMS was feasible, tolerable, and effective for adolescents with treatment-resistant depression. Larger, blinded, sham-controlled trials are needed for definitive safety and efficacy data. Further efforts to understand optimal delivery, dosing, and biomarker development for rTMS treatments of adolescent depression are warranted.

  18. Noninvasive brain stimulation with transcranial magnetic or direct current stimulation (TMS/tDCS)-From insights into human memory to therapy of its dysfunction.

    Science.gov (United States)

    Sparing, Roland; Mottaghy, Felix M

    2008-04-01

    Noninvasive stimulation of the brain by means of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) has driven important discoveries in the field of human memory functions. Stand-alone or in combination with other brain mapping techniques noninvasive brain stimulation can assess issues such as location and timing of brain activity, connectivity and plasticity of neural circuits and functional relevance of a circumscribed brain area to a given cognitive task. In this emerging field, major advances in technology have been made in a relatively short period. New stimulation protocols and, especially, the progress in the application of tDCS have made it possible to obtain longer and much clearer inhibitory or facilitatory effects even after the stimulation has ceased. In this introductory review, we outline the basic principles, discuss technical limitations and describe how noninvasive brain stimulation can be used to study human memory functions in vivo. Though improvement of cognitive functions through noninvasive brain stimulation is promising, it still remains an exciting challenge to extend the use of TMS and tDCS from research tools in neuroscience to the treatment of neurological and psychiatric patients.

  19. Timing Solution and Single-pulse Properties for Eight Rotating Radio Transients

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    Cui, B.-Y.; McLaughlin, M. A. [Department of Physics and Astronomy West Virginia University Morgantown, WV 26506 (United States); Boyles, J. [Department of Physics and Astronomy West Kentucky University Bowling Green, KY 42101 (United States); Palliyaguru, N. [Physics and Astronomy Department Texas Tech University Lubbock, TX 79409-1051 (United States)

    2017-05-01

    Rotating radio transients (RRATs), loosely defined as objects that are discovered through only their single pulses, are sporadic pulsars that have a wide range of emission properties. For many of them, we must measure their periods and determine timing solutions relying on the timing of their individual pulses, while some of the less sporadic RRATs can be timed by using folding techniques as we do for other pulsars. Here, based on Parkes and Green Bank Telescope (GBT) observations, we introduce our results on eight RRATs including their timing-derived rotation parameters, positions, and dispersion measures (DMs), along with a comparison of the spin-down properties of RRATs and normal pulsars. Using data for 24 RRATs, we find that their period derivatives are generally larger than those of normal pulsars, independent of any intrinsic correlation with period, indicating that RRATs’ highly sporadic emission may be associated with intrinsically larger magnetic fields. We carry out Lomb–Scargle tests to search for periodicities in RRATs’ pulse detection times with long timescales. Periodicities are detected for all targets, with significant candidates of roughly 3.4 hr for PSR J1623−0841 and 0.7 hr for PSR J1839−0141. We also analyze their single-pulse amplitude distributions, finding that log-normal distributions provide the best fits, as is the case for most pulsars. However, several RRATs exhibit power-law tails, as seen for pulsars emitting giant pulses. This, along with consideration of the selection effects against the detection of weak pulses, imply that RRAT