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Sample records for isolated head tremor

  1. Isolated tongue tremor after gamma knife radiosurgery for acoustic schwannoma.

    Science.gov (United States)

    Chung, Sun J; Im, Joo-Hyuk; Lee, Jae-Hong; Cho, A-Hyun; Kwon, Miseon; Lee, Myoung C

    2005-01-01

    We describe a patient who had an isolated tongue tremor with an audible click after gamma knife radiosurgery for acoustic schwannoma. The nature of the tongue tremor was clearly demonstrated by videofluoroscopy. The possible pathogenic mechanisms are discussed.

  2. Tremor

    Science.gov (United States)

    ... beta blockers (such as nadolol) and primidone, an anticonvulsant drug. Dystonic tremor may respond to clonazepam, anticholinergic ... beta blockers (such as nadolol) and primidone, an anticonvulsant drug. Dystonic tremor may respond to clonazepam, anticholinergic ...

  3. Approach to a tremor patient

    Directory of Open Access Journals (Sweden)

    Soumya Sharma

    2016-01-01

    Full Text Available Tremors are commonly encountered in clinical practice and are the most common movement disorders seen. It is defined as a rhythmic, involuntary oscillatory movement of a body part around one or more joints. In the majority of the population, tremor tends to be mild. They have varying etiology; hence, classifying them appropriately helps in identifying the underlying cause. Clinically, tremor is classified as occurring at rest or action. They can also be classified based on their frequency, amplitude, and body part involved. Parkinsonian tremor is the most common cause of rest tremor. Essential tremor (ET and enhanced physiological tremor are the most common causes of action tremor. Isolated head tremor is more likely to be dystonic rather than ET. Isolated voice tremor could be considered to be a spectrum of ET. Psychogenic tremor is not a diagnosis of exclusion; rather, demonstration of various clinical signs is needed to establish the diagnosis. Severity of tremor and response to treatment can be assessed using clinical rating scales as well as using electrophysiological measurements. The treatment of tremor is symptomatic. Medications are effective in half the cases of essential hand tremor and in refractory patients; deep brain stimulation is an alternative therapy. Midline tremors benefit from botulinum toxin injections. It is also the treatment of choice in dystonic tremor and primary writing tremor.

  4. Tremor

    Science.gov (United States)

    ... interferes with your daily activities or causes embarrassment. Treatment depends on the cause. Tremor caused by a medical condition, such as hyperthyroidism, will likely get better when the condition is ...

  5. Tremor

    Science.gov (United States)

    ... physical activity, travel, and social engagements to avoid embarrassment or other consequences. The symptoms of essential tremor ... on the treatment or care of an individual patient should be obtained through consultation with a physician ...

  6. Clinical and Breed Characteristics of Idiopathic Head Tremor Syndrome in 291 Dogs: A Retrospective Study

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    Linda G. Shell

    2015-01-01

    Full Text Available Objective. To establish signalment and phenomenology of canine idiopathic head tremor syndrome (IHTS, an episodic head movement disorder of undetermined pathogenesis. Design. Retrospective case series. Animals. 291 dogs with IHTS diagnosed between 1999 and 2013. Procedures. Clinical information was obtained from an online community of veterinary information aggregation and exchange (Veterinary Information Network, 777 W Covell Boulevard, Davis, CA 95616 and conducted with their approval. Information on breed, sex, age of onset, tremor description, mentation during the event, effect of distractions and drugs, diagnostics, presence of other problems, and outcome was analyzed. Results. IHTS was found in 24 pure breeds. Bulldogs, Labrador Retrievers, Boxers, and Doberman Pinschers comprised 69%; mixed breeds comprised 17%. Average onset age was 29 months (range: 3 months to 12 years. First episode occurred before 48 months of age in 88%. Vertical (35%, horizontal (50%, and rotational (15% movements were documented. Possible trigger events were found in 21%. Mentation was normal in 93%. Distractions abated the tremor in 87%. Most dogs did not respond to antiepileptic drugs. Conclusions and Clinical Relevance. This retrospective study documents IHTS in many breeds including Labrador Retrievers, Boxers, and mixed breeds.

  7. Head tremor in patients with cervical dystonia: different outcome? Tremor cefálico em pacientes com distonia cervical: evolução diferente?

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    Clecio Godeiro-Junior

    2008-12-01

    Full Text Available OBJECTIVE: The association of cervical dystonia (CD with other movement disorders have been already described, but data on clinical outcome regarding these patients are scant. The aim of this paper was to investigate whether patients with CD and head tremor (HT would have a different outcome regarding to botulinum toxin type-A (BTX-A treatment response and clinical and demographic parameters. METHOD: We retrospectively evaluated 118 medical charts of patients with CD and divided them into two groups: with (HT+ and without (HT- head tremor. We compared the following clinical and demographic parameters: age at onset, disease duration, progression of symptoms, etiology, familial history, presence of hand tremor. We also analyzed the response to BTX-A according to Tsui score in both groups. RESULTS: The occurrence of head tremor in our sample was of 38.2%. The occurrence of postural hand tremor in the patients from the HT+ group was higher than in the HT- one (p=0.015 and if we compare BTX-A response in each group, we observe that patients with HT present a better outcome in a setting of longer follow-up. In HT+ group, Tsui score pre treatment was 10 (6-12.5 and after follow-up was 8 (5.5-10.5; pOBJETIVO: A associação de distonia cervical (DC com outros transtornos do movimento já foi descrita, mas há poucos dados quanto à evolução clínica destes pacientes. Avaliamos se os pacientes com DC e tremor cefálico (TC apresentam características clínicas e demográficas, assim como a resposta ao tratamento com toxina botulínica tipo A, diferentes. MÉTODOS: Analisamos retrospectivamente 118 prontuários de pacientes com DC e os dividimos em dois grupos: com (TC+ e sem (TC- tremor cefálico. Comparamos os seguintes parâmetros clínicos e demográficos entre os grupos: idade de início, duração da doença, progressão de sintomas, etiologia, história familiar, presença de tremor em mãos. Também analisamos a resposta ao tratamento com toxina

  8. Intention tremor after head injury. Clinical features and computed tomographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Iwadate, Yasuo; Saeki, Naokatsu; Namba, Hiroki; Odaki, Masaru; Oka, Nobuo.

    1989-02-01

    Eight cases of intention tremor as a late complication of head injury were investigated. The patients ranged in age from 3 to 24 years. All received severe head injuries and lapsed into coma immediately afterward (Glasgow Coma Scale scores /le/8). Six patients exhibited decerebration or decortication. Hemiparesis was present in six cases and oculomotor nerve palsy in four. In the chronic stage, all patients displayed some degree of impairment of higher cortical function and five had dysarthria and/or ataxia. Initial computed tomography (CT) scans within 3 hours after the injury were obtained in five cases, of which four showed a hemorrhagic lesion in the midbrain or its surroundings. Other CT findings were diffuse cerebral swelling (four cases), intraventricular hemorrhage (three), and multiple hemorrhagic lesions (two). In the chronic stage, generalized cortical atrophy or ventricular enlargement was noted in five cases. These clinical features and CT findings indicate diffuse brain damage as well as midbrain damage and may reflect shearing injury. (author).

  9. Genetics Home Reference: essential tremor

    Science.gov (United States)

    ... tremor that results from other disorders or known causes, such as Parkinson disease or head trauma. Essential tremor usually occurs ... tremor occurs. Severe cases are often misdiagnosed as Parkinson disease . Related Information What information ... causes of essential tremor are unknown. Researchers are studying ...

  10. Head and Arm Tremor in X-linked Spinal and Bulbar Muscular Atrophy

    Science.gov (United States)

    Aicua, Irene; Verhagen, Okker; Arenaza, Naroa; Cubo, Esther

    2014-01-01

    Background X-linked spinal and bulbar muscular atrophy (SBMA) is a rare adult-onset neuronopathy. Although tremor is known to occur in this disease, the number of reported cases of SBMA with tremor is rare, and the number with videotaped documentation is exceedingly rare. Our aim was to describe/document the characteristic signs of tremor in spinal and bulbar muscular atrophy. Case Report We report a case of a 58-year-old male with a positive family history of tremor. On examination, the patient had jaw and hand tremors but he also exhibited gynecomastia, progressive bulbar paresis, and wasting and weakness primarily in the proximal limb muscles. The laboratory tests revealed an elevated creatine phosphokinase. Genetic testing was positive for X-SBMA, with 42 CAG repeats. Discussion Essential tremor is one of the most common movement disorders, yet it is important for clinicians to be aware of the presence of other distinguishing features that point to alternative diagnoses. The presence of action tremor associated with muscle atrophy and gynecomastia should lead to a suspicion of SBMA. PMID:25374767

  11. Tremor in the elderly

    DEFF Research Database (Denmark)

    Deuschl, Günther; Petersen, Inge; Lorenz, Delia

    2015-01-01

    Isolated tremor in the elderly is commonly diagnosed as essential tremor (ET). The prevalence of tremor increases steeply with increasing age, whereas hereditary tremor is becoming less common. Moreover, late-manifesting tremor seems to be associated with dementia and earlier mortality. We...... hypothesize that different entities underlie tremor in the elderly. Two thousand four hundred forty-eight subjects from the Longitudinal Study of Aging Danish Twins older than 70 y answered screening questions for ET in 2001. Two thousan fifty-six (84%) participants drew Archimedes spirals to measure...... patients did not show an increased but rather a lower mortality rate although it was not statistically significant. Consistent with a slower than normal aging, they were also physically and cognitively better functioning than controls. Because incident tremors beyond 70 y of age show worse aging parameters...

  12. Head tremor and progressive multifocal leukoencephalopathy in AIDS patients: report of two cases Tremor cefálico e leucoencefalopatia multifocal progressiva em pacientes com SIDA: relato de dois casos

    Directory of Open Access Journals (Sweden)

    Carlos R.M. Rieder

    2005-03-01

    Full Text Available Progressive multifocal leukoencephalopathy (PML is caused by replication of JC virus in oligodendrocytes of immunocompromised patients. Common manifestations are focal motor and sensory deficits, gait abnormalities, speech and language disturbances, cognitive disorders, headache, and visual impairment. Although the occurrence of movement disorders is rare in PML, bradykinesia, rigidity, dystonia, myoclonic jerks and myoclonic ataxia have been described. Head tremor associated with PML has not been previously reported. We report two cases of PML in whom head tremor was present.A leucoencefalopatia multifocal progressiva (LMP é causada pela replicação do vírus JC em oligodendrócitos de pacientes imunocomprometidos. As manifestações mais comuns incluem déficits motores e sensitivos, alterações da marcha, da fala e da linguagem, cefaléia e distúrbios visuais e cognitivos. Embora a presença de distúrbios do movimento não seja tão freqüente na LMP, bradicinesia, rigidez, abalos mioclônicos e ataxia mioclônica já foram descritos. Nós relatamos dois casos de LMP associados com tremor cefálico.

  13. Essential Tremor

    Science.gov (United States)

    ... propranolol or other beta blockers and primidone, an anticonvulsant drug. Eliminating tremor "triggers" such as caffeine and ... propranolol or other beta blockers and primidone, an anticonvulsant drug. Eliminating tremor "triggers" such as caffeine and ...

  14. 痉挛性斜颈和特发性头部震颤的临床研究%Clinical study on cervical dystonia and essential head tremor

    Institute of Scientific and Technical Information of China (English)

    刘宁疆; 张本恕

    2014-01-01

    目的:对比痉挛性斜颈(CD)患者中存在头部震颤组[HT(+)组],无头部震颤组[HT (-)组]和特发性头部震颤组(ET组)三组患者的临床特点。方法用回顾性的方法观察自1982年8月至2012年10月期间就诊于天津医科大学总医院神经内科门诊的188例CD患者,其中HT(+)组57例,HT(-)组59例和72例ET病例的临床表现,病程发展过程和家族史。分组和诊断标准依据肌张力障碍性震颤和特发性震颤的诊断标准。使用χ2和方差分析进行统计学分析。结果三组患者中,其中HT(+)组女性患者发病率高于HT(-)组(χ2=5.872,P=0.019),HT(+)组颈痛率24.6%高于仅由震颤引起的颈痛率11.3%(χ2=4.060,P=0.041),HT(+)组56.1%患者以HT作为首发症状,HT发生后4.89年出现斜颈。26.7%CD患者同时存在手部震颤,HT(+)组显著性高于HT(-)组(χ2=16.800,P=0.000),ET组69%的患者存在手颤,显著性高于HT(+)组(χ2=7.651, P=0.005)。HT(-),HT(+)和ET三组患者中,HT(-)组具有家族史阳性率最低(10.2%),与HT (+)组相比有显著性差异(χ2=9.201,P=0.002),而ET组具有震颤的家族史阳性率最高(37.5%)。结论 HT和斜颈是头颈部肌张力障碍的两个重要体征,两者可先后出现,并相互转化,而HT有时是其早期唯一的表现,不易与ET区别,在与手颤和具有震颤或其他运动障碍的家族史的患者中更易发生,支持CD与特发性震颤在发病机制上具有一定的关联。%Objective To compare the clinical characteristics,natural history of patients with cervical dystonia(CD)with head tremor [HT (+)],without head tremor [HT (-)]and essential head tremor(ET).Methods We prospectively evaluated 188 consecutive patients of CD including HT(+)57 patients,HT(-)59 patients and 72 patients of ET with a detailed

  15. Are Isolated Indigenous Populations Headed toward Extinction?

    National Research Council Canada - National Science Library

    Walker, Robert S; Kesler, Dylan C; Hill, Kim R

    2016-01-01

    .... Except in emergency situations, the current policy of governments in Brazil, Colombia, and Peru towards isolated tribes is a "leave them alone" strategy, in which isolated groups are left uncontacted...

  16. Are Isolated Indigenous Populations Headed toward Extinction?

    Directory of Open Access Journals (Sweden)

    Robert S Walker

    Full Text Available At least 50 indigenous groups spread across lowland South America remain isolated and have only intermittent and mostly hostile interactions with the outside world. Except in emergency situations, the current policy of governments in Brazil, Colombia, and Peru towards isolated tribes is a "leave them alone" strategy, in which isolated groups are left uncontacted. However, these no-contact policies are based on the assumption that isolated populations are healthy and capable of persisting in the face of mounting external threats, and that they can maintain population viability in the long-term. Here, we test this assumption by tracking the sizes and movements of cleared horticultural areas made by 8 isolated groups over the last 10-14 years. We used deforestation data derived from remote sensing Landsat satellite sensors to identify clearings, and those were then validated and assessed with high-resolution imagery. We found only a single example of a relatively large and growing population (c. 50 cleared ha and 400 people, whereas all of the other 7 groups exhibited much smaller villages and gardens with no sizable growth through time. These results indicated that the smaller groups are critically endangered, and it prompts an urgent re-thinking of policies toward isolated populations, including plans for well-organized contacts that may help save lives and rescue isolated indigenous populations from imminent extinction.

  17. Unusual Forehead Tremor in Four Patients with Essential Tremor

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    Jordi Gascón-Bayarri

    2012-01-01

    Full Text Available Forehead tremor has only been reported in two patients with essential tremor, one with rhythmic tremor and the other with dystonic tremor. We report 4 new patients with essential tremor who present a 4–6 Hz frontal tremor registered by electromyography and unusual features like frontal tremor preceding limb tremor or unilateral involvement. Frontal tremor is present in some patients with essential tremor, sometimes preceding limb tremor. Treatment with botulinum toxin may be useful.

  18. Essential Tremor Is More Than a Tremor

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    Full Text Available Home About the IETF Volunteer For Healthcare Providers Giving Options Donate Prev Next IETF > About Essential Tremor > ... Parkinson’s disease and essential tremor symptoms Raving Fan Home About the IETF Volunteer For Healthcare Providers Giving ...

  19. Essential Tremor Is More Than a Tremor

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    Full Text Available ... in new window) Click to email this to a friend (Opens in new window) Click to print ( ... in new window) Essential Tremor is More Than a Tremor Providing a voice for people with essential ...

  20. Essential Tremor Is More Than a Tremor

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    Full Text Available ... in new window) Click to email this to a friend (Opens in new window) Click to print ( ... in new window) Essential Tremor is More Than a Tremor Providing a voice for people with essential ...

  1. The phenomenology of parkinsonian tremor.

    Science.gov (United States)

    Deuschl, Günther; Papengut, Frank; Hellriegel, Helge

    2012-01-01

    The definition of Parkinsonian tremor covers all different forms occurring in Parkinson's disease. The most common form is rest tremor, labelled as typical Parkinsonian tremor. Other variants cover also postural and action tremors. Data support the notion that suppression of rest tremor may be more specific for PD tremors. Several differential diagnoses like rest tremor in ET, dystonic tremor, psychogenic tremor and Holmes' tremor may be misinterpreted as PD-tremor. Tests and clinical clues to separate them are presented. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Bilateral primary writing tremor.

    Science.gov (United States)

    Jimenez-Jimenez; Cabrera-Valdivia; Orti-Pareja; Gasalla; Tallon-Barranco; Zurdo

    1998-11-01

    Primary writing tremor is a task-specific tremor that is considered to be unilateral. We report a 59-year-old man with a 5-year history of a typical primary writing tremor in the right hand who developed similar symptoms in the left hand. Copyright 1998 Lippincott Williams & Wilkins

  3. Isolated traumatic head injury in children: Analysis of 276 observations

    Directory of Open Access Journals (Sweden)

    Bahloul Mabrouk

    2011-01-01

    Full Text Available Background : To determine predictive factors of mortality among children after isolated traumatic brain injury. Materials and Methods : In this retrospective study, we included all consecutive children with isolated traumatic brain injury admitted to the 22-bed intensive care unit (ICU of Habib Bourguiba University Hospital (Sfax, Tunisia. Basic demographic, clinical, biochemical, and radiological data were recorded on admission and during ICU stay. Results : There were 276 patients with 196 boys (71% and 80 girls, with a mean age of 6.7 ± 3.8 years. The main cause of trauma was road traffic accident (58.3%. Mean Glasgow Coma Scale score was 8 ± 2, Mean Injury Severity Score (ISS was 23.3 ± 5.9, Mean Pediatric Trauma Score (PTS was 4.8 ± 2.3, and Mean Pediatric Risk of Mortality (PRISM was 10.8 ± 8. A total of 259 children required mechanical ventilation. Forty-eight children (17.4% died. Multivariate analysis showed that factors associated with a poor prognosis were PRISM > 24 (OR: 10.98, neurovegetative disorder (OR: 7.1, meningeal hemorrhage (OR: 2.74, and lesion type VI according to Marshall tomographic grading (OR: 13.26. Conclusion : In Tunisia, head injury is a frequent cause of hospital admission and is most often due to road traffic injuries. Short-term prognosis is influenced by demographic, clinical, radiological, and biochemical factors. The need to put preventive measures in place is underscored.

  4. Variations on tremor parameters

    Science.gov (United States)

    Boose, A.; Jentgens, Ch.; Spieker, S.; Dichgans, J.

    1995-03-01

    This paper describes our analysis procedure for long-term tremor EMG recordings, as well as three examples of applications. The description of the method focuses on how characteristics of the tremor (e.g. frequency, intensity, agonist-antagonist interaction) can be defined and calculated based on surface EMG data. The resulting quantitative characteristics are called ``tremor parameters.'' We discuss sinusoidally modulated, band-limited white noise as a model for pathological tremor-EMG, and show how the basic parameters can be extracted from this class of signals. The method is then applied to (1) estimate tremor severity in clinical studies, (2) quantify agonist-antagonist interaction, and (3) investigate the variations of the tremor parameters using simple methods from time-series analysis.

  5. Embarrassment in essential tremor: prevalence, clinical correlates and therapeutic implications.

    Science.gov (United States)

    Louis, Elan D; Rios, Eileen

    2009-08-01

    Embarrassment is a commonly described feature of essential tremor (ET) but has not been the focus of clinical research. To estimate the prevalence, identify susceptible patient groups, and quantify the therapeutic correlates of reported embarrassment. A total of 106 ET cases from a population-based sample and 349 ET cases from a clinical sample were asked, "Does your tremor often embarrass you?" In the clinical sample, the prevalence of embarrassment was high (58.2%). Even in those ET cases with no head tremor and mild arm tremor, nearly one-half (29/61 [47.5%]) reported embarrassment. While the prevalence of embarrassment was lower in the population-based sample, it was not negligible (18.9%). Embarrassment was associated with younger age of onset (p=0.003) and women were nearly twice as likely as men to report embarrassment (OR=1.85, p=0.01). Independent of tremor severity, embarrassment nearly doubled the odds of using tremor medication (OR=1.86, p=0.01). Embarrassment may be a source of disability in ET. Even among clinic patients with mild tremor, nearly one-half reported embarrassment. We identified a number of patient characteristics linked to embarrassment. Embarrassment alone (i.e., independent of tremor severity) was responsible for a doubling of tremor medication usage. The majority of clinical trials do not assess the therapeutic effects of medication on embarrassment. These trials may benefit from scaled assessments of level of embarrassment.

  6. Essential Tremor Is More Than a Tremor

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    Full Text Available ... Essential Tremor > Video Video Click to share on Facebook (Opens in new window) Click to share on Twitter (Opens in new window) Click to share on Google+ (Opens in new window) Click to email this to a friend (Opens in new window) Click to print (Opens ...

  7. Are Isolated Indigenous Populations Headed toward Extinction?: e0150987

    National Research Council Canada - National Science Library

    Robert S Walker; Dylan C Kesler; Kim R Hill

    2016-01-01

    .... Except in emergency situations, the current policy of governments in Brazil, Colombia, and Peru towards isolated tribes is a "leave them alone" strategy, in which isolated groups are left uncontacted...

  8. Tremor - self-care

    Science.gov (United States)

    ... your provider about how you can change your sleep habits if you have problems sleeping. Stress and anxiety can also make your tremor worse. These things may lower your stress level: Meditation, deep relaxation, or breathing exercises Reducing your caffeine ...

  9. Integration of Osteopathic Manual Treatments in Management of Cervical Dystonia with Tremor: A Case Series

    Science.gov (United States)

    Halimi, Miriam; Leder, Adena; Mancini, Jayme D.

    2017-01-01

    Background Cervical dystonia, also known as spasmodic torticollis, is a chronic disorder in which patients exhibit involuntary repetitive contractions of neck muscles resulting in abnormal postures or movements. Occasionally, there is also a dystonic head tremor. The underlying mechanisms for cervical dystonia and dystonic tremor are not clear, and treatments are limited. Case Report In the present cases, two females with head tremor starting in adolescence developed worsening symptoms of cervical dystonia with dystonic tremor in their 60s. On osteopathic physical examination, both had a vertical type strain to the sphenobasilar synchondrosis. Discussion Vertical strains are more frequently found in patients after head trauma, congenital or later in life, than in healthy patients, and head trauma may have been a precipitating factor in these patients. There were improvements in cervical dystonia symptoms, including tremor, in both patients after osteopathic manual treatment. PMID:28119789

  10. Optimal Impact Isolation for Injury Prevention Evaluated by the Head Injury Criterion

    Directory of Open Access Journals (Sweden)

    D.V. Balandin

    2007-01-01

    Full Text Available The optimal control of the deceleration of a particle moving along a straight line after an impact against an isolated surface is considered. The force applied to the particle by the surface is treated as the control variable. The deceleration distance is minimized subject to a constraint on the Head Injury Criterion functional. This functional is an integral criterion that is utilized in engineering biomechanics to evaluate the expected severity of impact-induced head injury of a human being. The solution obtained provides characteristics of the limiting capabilities for the prevention of head injuries by means of an impact isolator, such as a coating of the surface against which the impacts occur. The head injuries can be due to impact occurrences, including traffic crashes, falling, and contacts with ballistic objects.

  11. Seismic moulin tremor

    Science.gov (United States)

    Roeoesli, Claudia; Walter, Fabian; Ampuero, Jean-Paul; Kissling, Edi

    2016-08-01

    Through glacial moulins, meltwater is routed from the glacier surface to its base. Moulins are a main feature feeding subglacial drainage systems and thus influencing basal motion and ice dynamics, but their geometry remains poorly known. Here we show that analysis of the seismic wavefield generated by water falling into a moulin can help constrain its geometry. We present modeling results of hour-long seimic tremors emitted from a vertical moulin shaft, observed with a seismometer array installed at the surface of the Greenland Ice Sheet. The tremor was triggered when the moulin water level exceeded a certain height, which we associate with the threshold for the waterfall to hit directly the surface of the moulin water column. The amplitude of the tremor signal changed over each tremor episode, in close relation to the amount of inflowing water. The tremor spectrum features multiple prominent peaks, whose characteristic frequencies are distributed like the resonant modes of a semiopen organ pipe and were found to depend on the moulin water level, consistent with a source composed of resonant tube waves (water pressure waves coupled to elastic deformation of the moulin walls) along the water-filled moulin pipe. Analysis of surface particle motions lends further support to this interpretation. The seismic wavefield was modeled as a superposition of sustained wave radiation by pressure sources on the side walls and at the bottom of the moulin. The former was found to dominate the wave field at close distance and the latter at large distance to the moulin.

  12. The pathophysiology of essential tremor and Parkinson's tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Toni, I.; Deuschl, G.; Bloem, B.R.

    2013-01-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop ne

  13. The Pathophysiology of Essential Tremor and Parkinson's Tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Toni, I.; Deuschl, G.; Bloem, B.R.

    2013-01-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop ne

  14. Isolated Pancreatic Histoplasmosis: An Unusual Suspect of Pancreatic Head Mass in an Immunocompetent Host.

    Science.gov (United States)

    Aggarwal, Avin; Garg, Shashank

    2015-01-01

    Histoplasmosis is endemic to the Mississippi and Ohio River valley regions in the US. It usually affects patients with underlying immunodeficiency but can also be seen in immunocompetent hosts. Although gastrointestinal involvement is common in the setting of disseminated histoplasmosis, isolated gastrointestinal involvement is uncommon. We report a case of isolated pancreatic histoplasmosis in an immunocompetent patient, presenting as painless jaundice and pancreatic head mass.

  15. Isolation and characterization of satellite cells from rat head branchiomeric muscles

    NARCIS (Netherlands)

    Carvajal Monroy, P.L.; Yablonka-Reuveni, Z.; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, F.A.D.T.G.; Hoff, Von den J.W.

    2015-01-01

    This protocol describes the isolation of satellite cells from branchiomeric head muscles of a 9 week-old rat. The muscles originate from different branchial arches. Subsequently, the satellite cells are cultured on a spot coating of millimeter size to study their differentiation. This approach avoid

  16. Tremor in multiple sclerosis

    NARCIS (Netherlands)

    Koch, Marcus; Mostert, Jop; Heersema, Dorothea; De Keyser, Jacques

    2007-01-01

    Tremor is estimated to occur in about 25 to 60 percent of patients with multiple sclerosis (MS). This symptom, which can be severely disabling and embarrassing for patients, is difficult to manage. Isoniazid in high doses, carbamazepine, propranolol and gluthetimide have been reported to provide som

  17. How typical are 'typical' tremor characteristics? : Sensitivity and specificity of five tremor phenomena

    NARCIS (Netherlands)

    van der Stouwe, A. M. M.; Elting, J. W.; van der Hoeven, J. H.; van Laar, T.; Leenders, K. L.; Maurits, N. M.; Tijssen, M. Aj.

    2016-01-01

    Introduction: Distinguishing between different tremor disorders can be challenging. Some tremor disorders are thought to have typical tremor characteristics: the current study aims to provide sensitivity and specificity for five 'typical' tremor phenomena. Methods: Retrospectively, we examined 210 t

  18. The pathophysiology of essential tremor and Parkinson's tremor.

    Science.gov (United States)

    Helmich, Rick C; Toni, Ivan; Deuschl, Günther; Bloem, Bastiaan R

    2013-09-01

    We review recent evidence about the pathophysiology of essential tremor and tremor in Parkinson's disease. We believe that a network perspective is necessary to understand this common neurological symptom, and that knowledge of cerebral network dysfunction in tremor disorders will help to develop new therapies. Both essential tremor and Parkinson's tremor are associated with increased activity in the cerebellothalamocortical circuit. However, different pathophysiological mechanisms lead to tremulous activity within this circuit. In Parkinson's disease, evidence suggests that dopaminergic dysfunction of the pallidum triggers increased activity in the cerebellothalamocortical circuit. In essential tremor, GABAergic dysfunction of the cerebellar dentate nucleus and brain stem, possibly caused by neurodegeneration in these regions, may lead to tremulous activity within the cerebellothalamocortical circuit. In both disorders, network parameters such as the strength and directionality of interregional coupling are crucially altered. Exciting new research uses these network parameters to develop network-based therapies, such as closed-loop deep brain stimulation and transcranial magnetic or direct current stimulation.

  19. Cohort study of prevalence and phenomenology of tremor in dementia with Lewy bodies.

    Science.gov (United States)

    Onofrj, Marco; Varanese, Sara; Bonanni, Laura; Taylor, John-Paul; Antonini, Angelo; Valente, Enza Maria; Petrucci, Simona; Stocchi, Fabrizio; Thomas, Astrid; Perfetti, Bernardo

    2013-07-01

    To study prevalence, specific patterns and response to treatment of tremor in dementia with Lewy bodies (DLB), in comparison with other tremulous disorders prevalence, qualitative and quantitative features of tremor were studied in an incident cohort of 67 dopaminergic treatment naive DLB, 111 Parkinson's Disease (PD) and 34 Essential Tremor (ET) patients. Tremulous DLB patients (tDLB) were compared with tremulous PD (tPD) and ET patients and followed for 2 years. Double blind placebo-controlled acute drug challenge with L-Dopa and alcohol was performed in all ET, 24 tDLB and 27 tPD. Effects of dopaminergic chronic treatment in all tDLB and tPD patients and primidone in 8 tDLB were also assessed. Tremor occurred in 44.76 % of DLB patients. The tDLB patients presented a complex pattern of mixed tremors, characterized by rest and postural/action tremor, including walking tremor and standing overflow in 50 % tDLB. Standing tremor with overflow was characteristic of tDLB (p < 0.001). Head tremor was more frequent in tDLB than tPD and ET (p = 0.001). The tDLB tremors were reduced by acute and chronic dopaminergic treatments (p < 0.01) but not by alcohol or primidone. Tremor occurs commonly in DLB patients with a complex mixed tremor pattern which shows a significant response to acute and chronic dopaminergic treatments. Recognizing that there is a clinical category of tremulous DLB may help the differential diagnosis of tremors.

  20. Episodic tremor triggers small earthquakes

    Science.gov (United States)

    Balcerak, Ernie

    2011-08-01

    It has been suggested that episodic tremor and slip (ETS), the weak shaking not associated with measurable earthquakes, could trigger nearby earthquakes. However, this had not been confirmed until recently. Vidale et al. monitored seismicity in the 4-month period around a 16-day episode of episodic tremor and slip in March 2010 in the Cascadia region. They observed five small earthquakes within the subducting slab during the ETS episode. They found that the timing and locations of earthquakes near the tremor suggest that the tremor and earthquakes are related. Furthermore, they observed that the rate of earthquakes across the area was several times higher within 2 days of tremor activity than at other times, adding to evidence of a connection between tremor and earthquakes. (Geochemistry, Geophysics, Geosystems, doi:10.1029/2011GC003559, 2011)

  1. Traumatic pneumorrachis after isolated closed head injuries: An up-to-date review.

    Science.gov (United States)

    Hadjigeorgiou, Georgios F; Singh, Ranjodh; Stefanopoulos, Panagiotis; Petsanas, Adamantios; Hadjigeorgiou, Fivos G; Fountas, Kostas

    2016-12-01

    Pneumorrachis (PR) is characterized by the presence of air within the spinal canal. It can be classified descriptively into internal or intradural and external or epidural. The causes of PR can be divided as iatrogenic, nontraumatic and traumatic. In the present study, a comprehensive literature search was conducted to identify all previous cases of PR after an isolate head injury. Two additional cases were also reported. We concluded, that PR after isolated head injuries is a rare but likely an underdiagnosed entity. It is a marker of severe injury and the majority of such patients have a poor outcome. Although, PR is usually asymptomatic and reabsorbs spontaneously, prompt recognition and management of the underlying cause is essential. Therefore, clinicians should maintain a high level of suspicion for serious underlying injury in cases where initial radiological imaging reveals intraspinal air.

  2. 21 CFR 882.1950 - Tremor transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain diseases...

  3. Widespread triggering of nonvolcanic tremor in California.

    Science.gov (United States)

    Gomberg, Joan; Rubinstein, Justin L; Peng, Zhigang; Creager, Kenneth C; Vidale, John E; Bodin, Paul

    2008-01-11

    We identified seven locations on or near the transform plate boundary in California where nonvolcanic tremor was triggered by the 2002 Denali earthquake. This result implies that the conditions essential for nonvolcanic tremor exist in a range of tectonic environments. Models explaining tremor typically require conditions endemic to subduction zones, that is, high temperatures and fluid pressures, because previously tremor was nearly exclusively documented in subduction zones. The absence of tremor in geothermal areas is inconsistent with such models. Additionally, we found no correlation between creeping or locked faults and tremor, contrary to predictions of frictional models of tremor.

  4. Hereditary chin tremor in Parkinson's disease.

    Science.gov (United States)

    Erer, Sevda; Jankovic, Joseph

    2007-11-01

    Hereditary chin tremor (HCT) is characterized by rhythmical, involuntary movements of the chin muscles usually inherited in an autosomal dominant pattern. We describe a 74-year old man with familial, childhood-onset chin tremor, and a 3-year history of progressive hand tremor, gait difficulty, and other parkinsonian features. Since chin tremor often occurs in Parkinson's disease (PD), a coexistent HCT may not be recognized unless past and family history of tremor is carefully explored.

  5. Decreased Cerebellar Fiber Density in Cortical Myoclonic Tremor but Not in Essential Tremor

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; Caan, Matthan W. A.; Tijssen, Marina A. J.; Hoogduin, Johannes M.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    Pathophysiology of tremor generation remains uncertain in 'familial cortical myoclonic tremor with epilepsy' (FCMTE) and essential tremor (ET). In both disorders, imaging and pathological studies suggest involvement of the cerebellum and its projection areas. MR diffusion tensor imaging allows

  6. Decreased Cerebellar Fiber Density in Cortical Myoclonic Tremor but Not in Essential Tremor

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; Caan, Matthan W. A.; Tijssen, Marina A. J.; Hoogduin, Johannes M.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    2013-01-01

    Pathophysiology of tremor generation remains uncertain in 'familial cortical myoclonic tremor with epilepsy' (FCMTE) and essential tremor (ET). In both disorders, imaging and pathological studies suggest involvement of the cerebellum and its projection areas. MR diffusion tensor imaging allows estim

  7. Role of altered cerebello-thalamo-cortical network in the neurobiology of essential tremor

    Energy Technology Data Exchange (ETDEWEB)

    Lenka, Abhishek; Bhalsing, Ketaki Swapnil; Jhunjhunwala, Ketan [National Institute of Mental Health and Neurosciences, Department of Neurology, Bangalore, Karnataka (India); National Institute of Mental Health and Neurosciences, Department of Clinical Neurosciences, Bangalore, Karnataka (India); Panda, Rajanikant; Saini, Jitender; Bharath, Rose Dawn [National Institute of Mental Health and Neurosciences, Department of Neuroimaging and Interventional Radiology, Bangalore, Karnataka (India); Naduthota, Rajini M.; Yadav, Ravi; Pal, Pramod Kumar [National Institute of Mental Health and Neurosciences, Department of Neurology, Bangalore, Karnataka (India)

    2017-02-15

    Essential tremor (ET) is the most common movement disorder among adults. Although ET has been recognized as a mono-symptomatic benign illness, reports of non-motor symptoms and non-tremor motor symptoms have increased its clinical heterogeneity. The neural correlates of ET are not clearly understood. The aim of this study was to understand the neurobiology of ET using resting state fMRI. Resting state functional MR images of 30 patients with ET and 30 age- and gender-matched healthy controls were obtained. The functional connectivity of the two groups was compared using whole-brain seed-to-voxel-based analysis. The ET group had decreased connectivity of several cortical regions especially of the primary motor cortex and the primary somatosensory cortex with several right cerebellar lobules compared to the controls. The thalamus on both hemispheres had increased connectivity with multiple posterior cerebellar lobules and vermis. Connectivity of several right cerebellar seeds with the cortical and thalamic seeds had significant correlation with an overall score of Fahn-Tolosa-Marin tremor rating scale (FTM-TRS) as well as the subscores for head tremor and limb tremor. Seed-to-voxel resting state connectivity analysis revealed significant alterations in the cerebello-thalamo-cortical network in patients with ET. These alterations correlated with the overall FTM scores as well as the subscores for limb tremor and head tremor in patients with ET. These results further support the previous evidence of cerebellar pathology in ET. (orig.)

  8. Cluster Head Selection in a Homogeneous Wireless Sensor Network Ensuring Full Connectivity with Minimum Isolated Nodes

    Directory of Open Access Journals (Sweden)

    Tapan Kumar Jain

    2014-01-01

    Full Text Available The research work proposes a cluster head selection algorithm for a wireless sensor network. A node can be a cluster head if it is connected to at least one unique neighbor node where the unique neighbor is the one that is not connected to any other node. If there is no connected unique node then the CH is selected on the basis of residual energy and the number of neighbor nodes. With the increase in number of clusters, the processing energy of the network increases; hence, this algorithm proposes minimum number of clusters which further leads to increased network lifetime. The major novel contribution of the proposed work is an algorithm that ensures a completely connected network with minimum number of isolated nodes. An isolated node will remain only if it is not within the transmission range of any other node. With the maximum connectivity, the coverage of the network is automatically maximized. The superiority of the proposed design is verified by simulation results done in MATLAB, where it clearly depicts that the total numbers of rounds before the network dies out are maximum compared to other existing protocols.

  9. Essential Tremor (ET): Surgical Options

    Science.gov (United States)

    ... t respond to propranolol, primidone, or other common ET medications and whose tremor has become debilitating, there ... treatments were first introduced. Current surgical options for ET include Deep Brain Stimulation (DBS) , Focused Ultrasound Thalamotomy , ...

  10. Essential tremor responsive to levetiracetam

    Directory of Open Access Journals (Sweden)

    Abdullah Yılgör

    2012-03-01

    Full Text Available Essential tremor is one of the most common movementdisorders with a prevalence of 0.4% to 3.9% in the generalpopulation and increases with age. The medical treatmentavailable for patients with essential tremor is ofteninadequate. Propranolol and primidone are the first-linetreatment options, improving in up to two thirds of cases.This article reports a satisfying response to levetiracetamwith disabling essential tremor in a 58-year-old man whompropranolol as well as primidone had to be discontinueddue to unresponsiveness and severe side effects. One ofthe antiepileptic drugs, levetiracetam, may be more usefulin the treatment of essential tremor. J Clin Exp Invest2012; 3(1: 108-110

  11. Tidal modulation of nonvolcanic tremor.

    Science.gov (United States)

    Rubinstein, Justin L; La Rocca, Mario; Vidale, John E; Creager, Kenneth C; Wech, Aaron G

    2008-01-11

    Episodes of nonvolcanic tremor and accompanying slow slip recently have been observed in the subduction zones of Japan and Cascadia. In Cascadia, such episodes typically last a few weeks and differ from "normal" earthquakes in their source location and moment-duration scaling. The three most recent episodes in the Puget Sound/southern Vancouver Island portion of the Cascadia subduction zone were exceptionally well recorded. In each episode, we saw clear pulsing of tremor activity with periods of 12.4 and 24 to 25 hours, the same as the principal lunar and lunisolar tides. This indicates that the small stresses associated with the solid-earth and ocean tides influence the genesis of tremor much more effectively than they do the genesis of normal earthquakes. Because the lithostatic stresses are 10(5) times larger than those associated with the tides, we argue that tremor occurs on very weak faults.

  12. Slip rate and tremor genesis in Cascadia

    Science.gov (United States)

    Wech, Aaron G.; Bartlow, Noel M.

    2014-01-01

    At many plate boundaries, conditions in the transition zone between seismogenic and stable slip produce slow earthquakes. In the Cascadia subduction zone, these events are consistently observed as slow, aseismic slip on the plate interface accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides spatially and temporally with tremor, leaving the physics of tremor genesis poorly understood. Here we analyze seismic, geodetic, and strainmeter data in Cascadia to observe for the first time a large, tremor-generating slow earthquake change from tremor-genic to silent and back again. The tremor falls silent at reduced slip speeds when the migrating slip front pauses as it loads the stronger adjacent fault segment to failure. The finding suggests that rheology and slip-speed-regulated stressing rate control tremor genesis, and the same section of fault can slip both with and without detectable tremor, limiting tremor's use as a proxy for slip.

  13. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  14. Postural and intention tremors: Detailed clinical study of essential tremor vs. Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Eliezer J Sternberg

    2013-05-01

    Full Text Available ABSTRACTBackground: An estimated 30-50% of essential tremor diagnoses are incorrect, and the true diagnosis in those patients is often Parkinson’s disease or other tremor disorders. There are general statements about the tremor in these essential tremor and Parkinson’s disease, but published data on the more subtle characteristics of tremor are surprisingly limited. Postural tremor may occur in both disorders, adding to the difficulty. There are several anecdotal impressions regarding specific features of postural tremor in essential tremor vs. Parkinson’s disease, including joint distribution (e.g., phalanges, metacarpal-phalangeal joints, wrist, tremor directionality (e.g., flexion-extension vs. pronation-supination, and presence of intention tremor. However, there is little data to support these impressions.Methods: In this cross-sectional study, 100 patients (essential tremor, 50 Parkinson’s disease underwent detailed videotaped neurological examinations. Arm tremor was rated by a movement disorder neurologist who assessed severity and directionality across multiple joints. Results: During sustained arm extension, essential tremor patients exhibited more wrist than metacarpal-phalangeal and phalangeal joint tremor than did Parkinson’s disease patients (p<0.001, and more wrist flexion-extension tremor than wrist pronation-supination tremor (p<0.001. During the finger-nose-finger maneuver, intention tremor was present in approximately one in four (28% essential tremor patients vs. virtually none (4% of the Parkinson’s patients (p<0.001.Conclusions: We evaluated the location, severity, and directionality of postural tremor in essential tremor and Parkinson’s disease, and the presence of intention tremor, observing several clinical differences. We hope that detailed phenomenological data on tremor in essential tremor and Parkinson’s disease will help practicing physicians delineate the two diseases.

  15. The Clinical Evaluation of Parkinson's Tremor.

    Science.gov (United States)

    Zach, Heidemarie; Dirkx, Michiel; Bloem, Bastiaan R; Helmich, Rick C

    2015-01-01

    Parkinson's disease harbours many different tremors that differ in distribution, frequency, and context in which they occur. A good clinical tremor assessment is important for weighing up possible differential diagnoses of Parkinson's disease, but also to measure the severity of the tremor as a basis for further tailored treatment. This can be challenging, because Parkinson's tremor amplitude is typically very variable and context-dependent. Here, we outline how we investigate Parkinson's tremor in the clinic. We describe a simple set of clinical tasks that can be used to constrain tremor variability (cognitive and motor co-activation, several specific limb postures). This may help to adequately characterize the tremor(s) occurring in a patient with Parkinson's disease.

  16. Neural correlates of dystonic tremor: a multimodal study of voice tremor in spasmodic dysphonia.

    Science.gov (United States)

    Kirke, Diana N; Battistella, Giovanni; Kumar, Veena; Rubien-Thomas, Estee; Choy, Melissa; Rumbach, Anna; Simonyan, Kristina

    2016-02-03

    Tremor, affecting a dystonic body part, is a frequent feature of adult-onset dystonia. However, our understanding of dystonic tremor pathophysiology remains ambiguous as its interplay with the main co-occurring disorder, dystonia, is largely unknown. We used a combination of functional MRI, voxel-based morphometry and diffusion-weighted imaging to investigate similar and distinct patterns of brain functional and structural alterations in patients with dystonic tremor of voice (DTv) and isolated spasmodic dysphonia (SD). We found that, compared to controls, SD patients with and without DTv showed similarly increased activation in the sensorimotor cortex, inferior frontal (IFG) and superior temporal gyri, putamen and ventral thalamus, as well as deficient activation in the inferior parietal cortex and middle frontal gyrus (MFG). Common structural alterations were observed in the IFG and putamen, which were further coupled with functional abnormalities in both patient groups. Abnormal activation in left putamen was correlated with SD onset; SD/DTv onset was associated with right putaminal volumetric changes. DTv severity established a significant relationship with abnormal volume of the left IFG. Direct patient group comparisons showed that SD/DTv patients had additional abnormalities in MFG and cerebellar function and white matter integrity in the posterior limb of the internal capsule. Our findings suggest that dystonia and dystonic tremor, at least in the case of SD and SD/DTv, are heterogeneous disorders at different ends of the same pathophysiological spectrum, with each disorder carrying a characteristic neural signature, which may potentially help development of differential markers for these two conditions.

  17. Holmes' tremor caused by midbrain cavernoma

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jun; LI Shi-ting; XU Shun-qing; WAN Liang

    2007-01-01

    @@ Holmes' tremor has been postulated as a syndrome attributed to those lesions that interrupt the dentatethalamic and the nigrostriatal tracts thus causing both an action and a rest tremor.1 It may arise from various underlying structural disorders including multiple sclerosis, stroke, or tumors. So far, to our knowledge, few studies on Holmes' tremor secondary to cavernoma have been reported.2 Here we report a case of disabling tremor,who harbored a cavernoma in the midbrain.

  18. Tremor UPDRS estimation in home environment.

    Science.gov (United States)

    Rigas, George; Gatsios, Dimitris; Fotiadis, Dimitrios I; Chondrogiorgi, Maria; Tsironis, Christos; Konitsiotis, Spyridon; Gentile, Giovanni; Marcante, Andrea; Antonini, Angelo

    2016-08-01

    In this paper, a method for the assessment of the Unified Parkinson Disease Rating scale (UPDRS) related to tremor is presented. The method described consists of hand resting and posture state detection, tremor detection and tremor quantification based on accelerometer and gyroscope readings from a wrist worn sensor. The initial results on PD patient recordings on home environment indicate the feasibility of the proposed method in monitoring UPDRS tremor in patient home environment.

  19. The Clinical Evaluation of Parkinson's Tremor

    NARCIS (Netherlands)

    Zach, H.; Dirkx, M.; Bloem, B.R.; Helmich, R.C.

    2015-01-01

    Parkinson's disease harbours many different tremors that differ in distribution, frequency, and context in which they occur. A good clinical tremor assessment is important for weighing up possible differential diagnoses of Parkinson's disease, but also to measure the severity of the tremor as a

  20. Parkinsonian tremor loses its alternating aspect during non-REM sleep and is inhibited by REM sleep.

    Science.gov (United States)

    Askenasy, J J; Yahr, M D

    1990-01-01

    Non-REM sleep transforms the waking alternating Parkinsonian tremor into subclinical repetitive muscle contractions whose amplitude and duration decrease as non-REM sleep progresses from stages I to IV. During REM sleep Parkinsonian tremor disappears while the isolated muscle events increase significantly. PMID:2246656

  1. Parkinsonian tremor loses its alternating aspect during non-REM sleep and is inhibited by REM sleep.

    OpenAIRE

    Askenasy, J. J.; Yahr, M D

    1990-01-01

    Non-REM sleep transforms the waking alternating Parkinsonian tremor into subclinical repetitive muscle contractions whose amplitude and duration decrease as non-REM sleep progresses from stages I to IV. During REM sleep Parkinsonian tremor disappears while the isolated muscle events increase significantly.

  2. Effects of alprazolam on cortical activity and tremors in patients with essential tremor.

    Directory of Open Access Journals (Sweden)

    Jaime Ibáñez

    Full Text Available BACKGROUND: Essential tremor (ET is characterised by postural and action tremors with a frequency of 4-12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake. METHODS: We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band. RESULTS: Alprazolam significantly attenuated tremors (EMG: 76.2 ± 22.68%, decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P<0.05. At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P<0.05. We also found a significant correlation (r = 0.757, P<0.001 between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range. CONCLUSIONS: This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor.

  3. Treatment of patients with essential tremor.

    Science.gov (United States)

    Deuschl, Günther; Raethjen, Jan; Hellriegel, Helge; Elble, Rodger

    2011-02-01

    Essential tremor is a common movement disorder. Tremor severity and handicap vary widely, but most patients with essential tremor do not receive a diagnosis and hence are never treated. Furthermore, many patients abandon treatment because of side-effects or poor efficacy. A newly developed algorithm, based on the logarithmic relation between tremor amplitude and clinical tremor ratings, can be used to compare the magnitude of effect of available treatments. Drugs with established efficacy (propranolol and primidone) produce a mean tremor reduction of about 50%. Deep brain stimulation (DBS) in the thalamic nucleus ventrointermedius or neighbouring subthalamic structures reduces tremor by about 90%. However, no controlled trials of DBS have been done, and the best target is still uncertain. Better drugs are needed, and controlled trials are required to determine the safety and efficacy of DBS in the nucleus ventrointermedius and neighbouring subthalamic structures. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Estimation of pathological tremor from recorded signals based on adaptive sliding fast Fourier transform

    Directory of Open Access Journals (Sweden)

    Shengxin Wang

    2016-06-01

    Full Text Available Pathological tremor is an approximately rhythmic movement and considerably affects patients’ daily living activities. Biomechanical loading and functional electrical stimulation are proposed as potential alternatives for canceling the pathological tremor. However, the performance of suppression methods is associated with the separation of tremor from the recorded signals. In this literature, an algorithm incorporating a fast Fourier transform augmented with a sliding convolution window, an interpolation procedure, and a damping module of the frequency is presented to isolate tremulous components from the measured signals and estimate the instantaneous tremor frequency. Meanwhile, a mechanism platform is designed to provide the simulation tremor signals with different degrees of voluntary movements. The performance of the proposed algorithm and existing procedures is compared with simulated signals and experimental signals collected from patients. The results demonstrate that the proposed solution could detect the unknown dominant frequency and distinguish the tremor components with higher accuracy. Therefore, this algorithm is useful for actively compensating tremor by functional electrical stimulation without affecting the voluntary movement.

  5. Avaliação vestibular no tremor essencial Vestibular evaluation in the essential tremor

    Directory of Open Access Journals (Sweden)

    Bianca Simone Zeigelboim

    2008-01-01

    Full Text Available TEMA: o tremor essencial é familial em cerca de 50% dos casos, com uma herança autossômica, possui início insidioso e é lentamente progressivo. PROCEDIMENTOS: avaliou-se no Setor de Otoneurologia de um Hospital Particular em fevereiro de 2007, uma paciente do sexo feminino, branca, 59 anos, casada, artista plástica, com história de tremor na cabeça desde os dois anos de idade (sic. A paciente relata queixa de tontura há vários meses de origem súbita sem acompanhamento de náusea e/ou queda. Nega perda de força muscular e formigamento em membros superiores e inferiores, rebaixamento da acuidade auditiva e zumbido. A paciente relata que um de seus filhos possuiu tremor nas mãos há dois anos e avós maternos e paternos com Parkinson. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica e avaliação vestibular por meio da vectoeletronistagmografia. RESULTADOS: observaram-se os seguintes achados ao exame vestibular: nistagmo de posicionamento com características centrais, nistagmo espontâneo presente com os olhos abertos, nistagmo semi-espontâneo do tipo múltiplo e hiper-reflexia em valor absoluto à prova calórica 20ºC (OD e OE. CONCLUSÃO: o exame vestibular mostrou-se sensível e importante para captar alterações em provas que sugerissem envolvimento do sistema nervoso central.BACKGROUND: essential tremors are family-related in about 50% of the cases with an autosomal inheritance and they register an insidious beginning with a slow progression. PROCEDURE: a 59 year old, white female patient, married and whose occupation is a plastic artist with a history of head tremors since she was two years (sic old was evaluated in the Otoneurology sector of a private hospital, during the period from February 2007. The patient had been complaining of dizziness from unknown origin for several months without accompanying nausea and/or falls. She denied any loss of muscular strength or tingling in her upper and lower

  6. Admissions for isolated nonoperative mild head injuries: Sharing the burden among trauma surgery, neurosurgery, and neurology.

    Science.gov (United States)

    Zhao, Ting; Mejaddam, Ali Y; Chang, Yuchiao; DeMoya, Marc A; King, David R; Yeh, Daniel D; Kaafarani, Haytham M A; Alam, Hasan B; Velmahos, George C

    2016-10-01

    Isolated nonoperative mild head injuries (INOMHI) occur with increasing frequency in an aging population. These patients often have multiple social, discharge, and rehabilitation issues, which far exceed the acute component of their care. This study was aimed to compare the outcomes of patients with INOMHI admitted to three services: trauma surgery, neurosurgery, and neurology. Retrospective case series (January 1, 2009 to August 31, 2013) at an academic Level I trauma center. According to an institutional protocol, INOMHI patients with Glasgow Coma Scale (GCS) of 13 to 15 were admitted on a weekly rotational basis to trauma surgery, neurosurgery, and neurology. The three populations were compared, and the primary outcomes were survival rate to discharge, neurological status at hospital discharge as measured by the Glasgow Outcome Score (GOS), and discharge disposition. Four hundred eighty-eight INOMHI patients were admitted (trauma surgery, 172; neurosurgery, 131; neurology, 185). The mean age of the study population was 65.3 years, and 58.8% of patients were male. Seventy-seven percent of patients has a GCS score of 15. Age, sex, mechanism of injury, Charlson Comorbidity Index, Injury Severity Score, Abbreviated Injury Scale in head and neck, and GCS were similar among the three groups. Patients who were admitted to trauma surgery, neurosurgery and neurology services had similar proportions of survivors (98.8% vs 95.7% vs 94.7%), and discharge disposition (home, 57.0% vs 61.6% vs 55.7%). The proportion of patients with GOS of 4 or 5 on discharge was slightly higher among patients admitted to trauma (97.7% vs 93.0% vs 92.4%). In a logistic regression model adjusting for Charlson Comorbidity Index CCI and Abbreviated Injury Scale head and neck scores, patients who were admitted to neurology or neurosurgery had significantly lower odds being discharged with GOS 4 or 5. While the trauma group had the lowest proportion of repeats of brain computed tomography (61

  7. Isolated varices over hepatic flexure colon indicating superior mesenteric venous thrombosis caused by uncinate pancreatic head cancer- a case report

    Institute of Scientific and Technical Information of China (English)

    Yu-Pin Ho; Chun-Jung Lin; Ming-Yao Su; Jeng-Hwei Tseng; Cheng-Tang Chiu; Pang-Chi Chen

    2005-01-01

    Very rare cases of varices involving right side colon were reported. Most of them were due to cirrhotic portal hypertension or other primary causes. No report case contributed to pancreatic cancer. Here, we reported a case of uncinate pancreatic cancer with the initial finding of isolated hepatic flexure colon varices. Following studies confirmed isolated varices involving hepatic flexure colon due to pancreatic cancer with occlusion of superior mesenteric vein. From this report, superior mesenteric vein occlusion caused by uncinate pancreatic head cancer should be considered as a differential diagnosis of colon varices.

  8. Streptomyces formicae sp. nov., a novel actinomycete isolated from the head of Camponotus japonicus Mayr.

    Science.gov (United States)

    Bai, Lu; Liu, Chongxi; Guo, Lifeng; Piao, Chenyu; Li, Zhilei; Li, Jiansong; Jia, Feiyu; Wang, Xiangjing; Xiang, Wensheng

    2016-02-01

    During a screening for novel and biotechnologically useful actinobacteria in insects, a novel actinomycete with antifungal activity, designated strain 1H-GS9(T), was isolated from the head of a Camponotus japonicus Mayr ant, which were collected from Northeast Agricultural University (Harbin, Heilongjiang, China). Strain 1H-GS9(T) was characterised using a polyphasic approach. The organism was found to have morphological and chemotaxonomic characteristics typical of members of the genus Streptomyces. 16S rRNA gene sequence similarity studies showed that strain 1H-GS9(T) belongs to the genus Streptomyces with high sequence similarities to Streptomyces scopuliridis DSM 41917(T) (98.8 %) and Streptomyces mauvecolor JCM 5002(T) (98.6 %). However, phylogenetic analysis based on the 16S rRNA gene sequence indicated that it forms a monophyletic clade with Streptomyces kurssanovii JCM 4388(T) (98.6 %), Streptomyces xantholiticus JCM 4282(T) (98.6 %) and Streptomyces peucetius JCM 9920(T) (98.5 %). Thus, a combination of DNA-DNA hybridization experiments and phenotypic tests were carried out between strain 1H-GS9(T) and the above-mentioned five strains, which further clarified their relatedness and demonstrated that strain 1H-GS9(T) could be distinguished from these strains. Therefore, the strain is concluded to represent a novel species of the genus Streptomyces, for which the name Streptomyces formicae sp. nov. is proposed. The type strain is 1H-GS9(T) (=CGMCC 4.7277(T) = DSM 100524(T)).

  9. Balance in essential tremor during tandem gait: is the first mis-step an important finding?

    Science.gov (United States)

    Cinar, N; Sahin, S; Okluoglu Onay, T; Karsidag, S

    2013-10-01

    Essential tremor (ET) is the most commonly diagnosed movement disorder. ET may cause substantial loss of motor skills and balance with advanced age. We compared abnormalities in tandem gait with daily activity and Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) scores in 90 ET patients. All patients performed a 15-step tandem three times. The mean of first mis-steps was accepted as the tandem index (TI). The mean age was 61.4 ± 17 years; the mean duration of tremor was 6.7 ± 4 years; and there were 36 men and 54 women. There was no significant difference for age or sex between patients and controls. Head (24.6%), jaw (5.5%), voice (11%), and tongue tremors (1.5%) were identified in ET patients. Rest (2.5%), postural (95%), and kinetic tremors (54%) were detected in the upper extremities. Postural tremor was found in the lower extremities of 5%. The mean TI was 8.3 ± 4 (median, 8) in ET patients, and 10.6 ± 3.9 (median, 10) in controls (p=0.04). Correlation analysis of TI and FTMTRS scores showed tandem gait was significantly correlated with age, total tremor score, postural and kinetic extremity tremor, writing, drawing, pouring, feeding, and working scores. Linear regression showed a significant effect of age and FTMTRS score on TI. The decrease in balance control is apparent with advancing age. Balance disorders were more pronounced in ET patients. Although first mis-step in tandem gait is not as detailed as dynamic balance tests, it can be a simple method for detecting balance disorders. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Development of rat oocytes following intracytoplasmic injection of sperm heads isolated from testicular and epididymal spermatozoa.

    Science.gov (United States)

    Said, S; Han, M-S; Niwa, K

    2003-07-01

    The possibility of obtaining normal development of rat oocytes following intracytoplasmic injection of rat sperm heads, obtained by sonicating spermatozoa from testes and epididymides, was evaluated. Irrespective of the source of spermatozoa, sperm heads were successfully injected into approximately 45% of oocytes used; after 9-12h of culture, approximately 55% of injected oocytes still had normal morphology. Of the oocytes injected with testicular sperm heads 45% were activated, with a female pronucleus and a second polar body, but significantly more oocytes (approximately 68%) injected with caput and cauda epididymal sperm heads were activated. Male pronuclear formation was observed in 67-84% of the activated oocytes, with no difference in the proportions among the different sources of sperm heads. When zygotes showing two pronuclei and a second polar body at 10h after injection were cultured in conditions that support development of 1-cell embryos produced in vivo, no embryos derived from testicular sperm heads developed to blastocysts after 120 h of culture. Development of embryos derived from cauda sperm heads was significantly higher at all points of assessment, while embryos from caput sperm showed an intermediate degree of development, compared with embryos from testicular spermatozoa. However, similar proportions (2-4%) of 1-cell embryos derived from all three groups of sperm heads developed into normal offspring after transfer to foster mothers; of the limited number of offspring tested, all were fertile. These results demonstrate that sperm heads from all sources tested are similar in their ability to contribute to full development of normal, fertile offspring.

  11. Model of Deep Non-Volcanic Tremor in Episodic Tremor and Slip Events

    Science.gov (United States)

    Gershenzon, N. I.; Bambakidis, G.

    2014-12-01

    Bursts of tremor accompany a moving slip pulse in Episodic Tremor and Slip (ETS) events. The sources of this non-volcanic tremor (NVT) are largely unknown. We have developed a model describing the mechanism of NTV generation. According to this model, NTV is a reflection of resonant-type oscillations excited in a fault at certain depth ranges. From a mathematical viewpoint, tremor (phonons) and slip pulses (solitons) are two different solutions of the sine-Gordon equation describing frictional processes inside a fault. In an ETS event, a moving slip pulse generates tremor due to interaction with structural heterogeneities in a fault and to failures of small asperities (see Figure). Observed tremor parameters, such as central frequency and frequency attenuation curve, are associated with fault parameters and conditions, such as elastic modulus, effective normal stress, penetration hardness and friction. Model prediction of NTV frequency content is consistent with observations. In the framework of this model it is possible to explain the complicated pattern of tremor migration, including rapid tremor propagation and reverse tremor migration. Migration along the strike direction is associated with movement of the slip pulse. Rapid tremor propagation in the slip-parallel direction is associated with movement of kinks along a 2D slip pulse. A slip pulse, pinned in some places, can fragment into several pulses, causing tremor associated with some of these pulse fragments to move opposite to the main propagation direction. The model predicts that the frequency content of tremor during an ETS event is slightly different from the frequency content of ambient tremor and tremor triggered by earthquakes. Figure 1. The slip velocity w of a slip pulse in time-space (x-t) coordinates moving in (a) ideal substrate and (b) substrate with a structural heterogeneity. Pulse is driven by constant external shear stress. Figure 1(b) shows that the pulse oscillates about an obstacle

  12. Clinical outcome and cost effectiveness of early tracheostomy in isolated severe head injury patients

    Directory of Open Access Journals (Sweden)

    Usman Tariq Siddiqui

    2015-01-01

    Conclusions: In patients with severe TBI, ET decreases total days of ventilation and ICU stay, and is associated with a decrease in the frequency of VAP. ET should be considered in severe head injury patients requiring prolong ventilatory support.

  13. Off with your heads: isolated organs in early Soviet science and fiction

    Science.gov (United States)

    Krementsov, Nikolai

    2009-01-01

    In the summer of 1925, a debutant writer, Aleksandr Beliaev, published a ‘scientific-fantastic story’, which depicted the travails of a severed human head living in a laboratory, supported by special machinery. Just a few months later, a young medical researcher, Sergei Briukhonenko, succeeded in reviving the severed head of a dog, using a special apparatus he had devised to keep the head alive. This paper examines the relationship between the literary and the scientific experiments with severed heads in post-revolutionary Russia, which reflected the anxieties about death, revival, and survival in the aftermath of the 1914–1923 ‘reign of death’ in that country. It contrasts the anguished ethical questions raised by the story with the public fascination for ‘science that conquers death’. PMID:19442924

  14. Off with your heads: isolated organs in early Soviet science and fiction.

    Science.gov (United States)

    Krementsov, Nikolai

    2009-06-01

    In the summer of 1925, a debutant writer, Aleksandr Beliaev, published a 'scientific-fantastic story', which depicted the travails of a severed human head living in a laboratory, supported by special machinery. Just a few months later, a young medical researcher, Sergei Briukhonenko, succeeded in reviving the severed head of a dog, using a special apparatus he had devised to keep the head alive. This paper examines the relationship between the literary and the scientific experiments with severed heads in post-revolutionary Russia, which reflected the anxieties about death, revival, and survival in the aftermath of the 1914-1923 'reign of death' in that country. It contrasts the anguished ethical questions raised by the story with the public fascination for 'science that conquers death'.

  15. The Parkfield tremors reveal slow and fast ruptures on the same asperity

    Science.gov (United States)

    Veedu, Deepa Mele; Barbot, Sylvain

    2016-04-01

    The deep extension of the San Andreas Fault is believed to be creeping, but the recent observations of tectonic tremors from these depths indicate a complex deformation style. In particular, an isolated tremor source near Parkfield has been producing a sequence of low-frequency earthquakes that indicates an uncommon mechanism of stress accumulation and release. The tremor pattern regularly oscillated between three and six days from mid-2003 until it was disrupted by the 2004 magnitude 6.0 Parkfield earthquake. After that event, the tremor source ruptured only about every three days, but over the next two years it gradually returned to its initial alternating recurrence pattern. The mechanism that drives this recurrence pattern is unknown. Here we use physics-based models to show that the same tremor asperity—the region from which the low-frequency earthquakes radiate—can regularly slip in slow and fast ruptures, naturally resulting in recurrence intervals alternating between three and six days. This unusual slip behaviour occurs when the tremor asperity size is close to the critical nucleation size of earthquakes. We also show that changes in pore pressure following the Parkfield earthquake can explain the sudden change and gradual recovery of the recurrence intervals. Our findings suggest a framework for fault deformation in which the same asperity can release tectonic stress through both slow and fast ruptures.

  16. Ambient tremors in a collisional orogenic belt

    Science.gov (United States)

    Chuang, Lindsay Yuling; Chen, Kate Huihsuan; Wech, Aaron G.; Byrne, Timothy; Peng, Wei

    2014-01-01

    Deep-seated tectonic tremors have been regarded as an observation tied to interconnected fluids at depth, which have been well documented in worldwide subduction zones and transform faults but not in a collisional mountain belt. In this study we explore the general features of collisional tremors in Taiwan and discuss the possible generation mechanism. In the 4 year data, we find 231 ambient tremor episodes with durations ranging from 5 to 30 min. In addition to a coseismic slip-induced stress change from nearby major earthquake, increased tremor rate is also highly correlated with the active, normal faulting earthquake swarms at the shallower depth. Both the tremor and earthquake swarm activities are confined in a small, area where the high attenuation, high thermal anomaly, the boundary between high and low resistivity, and localized veins on the surfaces distributed, suggesting the involvement of fluids from metamorphic dehydration within the orogen.

  17. Prevalence of clinically important traumatic brain injuries in children with minor blunt head trauma and isolated severe injury mechanisms.

    Science.gov (United States)

    Nigrovic, Lise E; Lee, Lois K; Hoyle, John; Stanley, Rachel M; Gorelick, Marc H; Miskin, Michelle; Atabaki, Shireen M; Dayan, Peter S; Holmes, James F; Kuppermann, Nathan

    2012-04-01

    To determine the prevalence of clinically important traumatic brain injuries (TBIs) with severe injury mechanisms in children with minor blunt head trauma but with no other risk factors from the Pediatric Emergency Care Applied Research Network (PECARN) TBI prediction rules (defined as isolated severe injury mechanisms). Secondary analysis of a large prospective observational cohort study. Twenty-five emergency departments participating in the PECARN. Children with minor blunt head trauma and Glasgow Coma Scale scores of at least 14. Treating clinicians completed a structured data form that included injury mechanism (severity categories defined a priori). Clinically important TBIs were defined as intracranial injuries resulting in death, neurosurgical intervention, intubation for more than 24 hours, or hospital admission for at least 2 nights. We investigated the rate of clinically important TBIs in children with either severe injury mechanisms or isolated severe injury mechanisms. Of the 42,412 patients enrolled in the overall study, 42,099 (99%) had injury mechanisms recorded, and their data were included for analysis. Of all study patients, 5869 (14%) had severe injury mechanisms, and 3302 (8%) had isolated severe injury mechanisms. Overall, 367 children had clinically important TBIs (0.9%; 95% CI, 0.8%-1.0%). Of the 1327 children younger than 2 years with isolated severe injury mechanisms, 4 (0.3%; 95% CI, 0.1%-0.8%) had clinically important TBIs, as did 12 of the 1975 children 2 years or older (0.6%; 95% CI, 0.3%-1.1%). Children with isolated severe injury mechanisms are at low risk of clinically important TBI, and many do not require emergent neuroimaging.

  18. Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

    Directory of Open Access Journals (Sweden)

    Ederson Cichaczewski

    2014-04-01

    Full Text Available Tremor in essential tremor (ET and Parkinson’s disease (PD usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. Objective: To present the electrophysiologic findings in PD and ET. Method: Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Results: Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2% also showed rest tremor. Conclusion: The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD.

  19. Model of deep non-volcanic tremor part II: episodic tremor and slip

    CERN Document Server

    Gershenzon, Naum I

    2014-01-01

    Bursts of tremor accompany a moving slip pulse in Episodic Tremor and Slip (ETS) events. The sources of this non-volcanic tremor (NVT) are largely unknown. We have developed a model describing the mechanism of NTV generation. According to this model, NTV is a reflection of resonant-type oscillations excited in a fault at certain depth ranges. From a mathematical viewpoint, tremor (phonons) and slip pulses (solitons) are two different solutions of the sine-Gordon equation describing frictional processes inside a fault. In an ETS event, a moving slip pulse generates tremor due to interaction with structural heterogeneities in a fault and to failures of small asperities. Observed tremor parameters, such as central frequency and frequency attenuation curve, are associated with fault parameters and conditions, such as elastic modulus, effective normal stress, penetration hardness and friction. Model prediction of NTV frequency content is consistent with observations. In the framework of this model it is possible t...

  20. Isolation and Characterization of a Novel Chitosan-Binding Protein from Non-Heading Chinese Cabbage Leaves

    Institute of Scientific and Technical Information of China (English)

    Hui-Ping CHEN; Lang-Lai XU

    2005-01-01

    To know the mechanism of ammonia assimilation in non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis (L.) Makino) leaves regulated by chitosan (CTS), a CTS-binding protein was isolated from non-heading Chinese cabbage leaves using the chitosan affinity chromatography approach and this CTS-binding protein was partially characterized. The profile of the 53.1 kDa purified protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was compared with the native molecular weight of 106.5 kDa, which indicated that the purified protein was a dimer with identical subunits. After isoelectric focusing, a band was obtained at pH 8.25. The agglutination test and periodic acid-Schiff staining further revealed that the protein was a glycoprotein with lectin activity. Moreover, the purified protein contained 17.4 % (w/w) neutral carbohydrate and 82.56% (w/w) protein. The comparison of this protein and the 67 kDa CTS-binding protein isolated previously from Rubus culture tissue exhibited some differences in characterization. According to results of peptide mass fingerprinting analysis, the protein purified in the present study does not show any similarity with any protein in the protein data bank. Thus, it was deduced that the protein purified in the present study is a novel CTS-binding protein.

  1. Evidence for a reversible drought induced shift in the species composition of mycotoxin producing Fusarium head blight pathogens isolated from symptomatic wheat heads.

    Science.gov (United States)

    Beyer, Marco; Pogoda, Friederike; Pallez, Marine; Lazic, Joëlle; Hoffmann, Lucien; Pasquali, Matias

    2014-07-16

    Fusarium species are fungal plant pathogens producing toxic secondary metabolites such as deoxynivalenol (DON), 15-acetyl-deoxynivalenol (15AcDON) and nivalenol (NIV). In Luxembourg, the Fusarium species composition isolated from symptomatic winter wheat heads was dominated by Fusarium graminearum sensu stricto strains (genetic 15AcDON chemotype) between the years 2009 and 2012, except for 2011, when Fusarium culmorum strains (genetic NIV chemotype) dominated the pathogen complex. Previous reports indicated that F. graminearum sensu stricto (genetic 15AcDON chemotype) was also most frequently isolated from randomly sampled winter wheat kernels including symptomatic as well as asymptomatic kernels in 2007 and 2008. The annual precipitation (average of 10 weather stations scattered across the country) decreased continuously from 924.31mm in 2007 over 917.15mm in 2008, to 843.38mm in 2009, 736.24mm in 2010, and 575.09mm in 2011. In 2012, the annual precipitation increased again to 854.70mm. Hardly any precipitation was recorded around the time of wheat anthesis in the years 2010 and 2011, whereas precipitation levels >50mm within the week preceding anthesis plus the week post anthesis were observed in the other years. The shift to genetic NIV chemotype F. culmorum strains in 2011 was accompanied by a very minor elevation of average NIV contents (2.9ngg(-1)) in the grain. Our data suggest that high NIV levels in Luxembourgish winter wheat are at present rather unlikely, because the indigenous F. culmorum strains with the genetic NIV chemotype seem to be outcompeted under humid in vivo conditions by F. graminearum DON producing strains on the one hand and seem to be inhibited - even though to a lower extent than DON producing strains - under dry in vivo conditions on the other hand.

  2. Beeinflussung des Essentiellen Tremors und des Tremors beim Morbus Parkinson durch transkranielle Gleichstromstimulation

    OpenAIRE

    Hellriegel, Helge

    2010-01-01

    Ziel dieser Arbeit war es die Rolle des primärmotorischen Kortex bei der Entstehung und Weiterleitung des Essentiellen Tremors und des Tremors beim Morbus Parkinson zu untersuchen. Hierzu wurde eine transkranielle Gleichstromstimulation über dem primärmotorischen Kortex bei Patienten mit oben genannten Tremorsyndromen durchgeführt und die klinischen sowie elektrophysiologisch messbaren Änderungen des Tremors beurteilt.

  3. Relationship between resting and action tremors in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Abdul Qayyum Rana

    2016-01-01

    Full Text Available Objective: To determine the relationship between resting tremor (RT and action tremor (AT in Parkinson's disease (PD patients. Methods: A retrospective study of RT and AT severity was conducted in 100 PD patients. The severity rating for each type of tremor in the upper extremities was assessed. The disparity in tremor severity between extremities for each tremor type was compared to that of the other two to identify commonalities in the laterality of the tremor manifestation. Results: Overall, RT is predictive of AT on the same side, but not the opposing side of the body. Patients with less intense resting right upper limb (RRU tremor and moderately intense RRU tremor were significantly more likely to have an action right upper limb (ARU tremor (−1.53, P = 0.020; −1.88, P = 0.005, respectively. Similarly, patients with less intense resting left upper limb (RLU tremor and moderately intense RLU tremors were significantly more likely to have an action left upper limb (ALU tremor (−3.49, P = 0.000; −1.86, P = 0.017, respectively. In addition, RRU and ALU tremors were associated with an increase in RLU and ARU tremors, respectively. Conclusion: Tremors are common findings in PD patients, and often impair quality of life. By identifying and classifying the relationship between resting and ATs in PD patients, our study sheds light onto the importance of better understanding and future management of this debilitating symptomology.

  4. Management of tremor in medieval Persia.

    Science.gov (United States)

    Zargaran, Arman; Zarshenas, Mohammad M; Mehdizadeh, Alireza; Mohagheghzadeh, Abdolali

    2013-01-01

    Tremor has been described in traditional systems of medicine throughout history. Persian medicine was one of those systems in medieval times and in it neurology and neurosurgery were also widely practiced and accepted. Based on the main Persian medical manuscripts, the current study focuses on the medieval concept of tremor as an important neurological disorder in order to clarify the development of neurology. Accordingly, three main approaches to the control and treatment of tremor in traditional Persian medicine are considered. First is lifestyle modification. The administration of simple medicines is the second, and the last is the application of compound medicines. Our study shows how much was known about tremor in traditional Persian medicine.

  5. Characteristics of Task-specific Tremor in String Instrument Players

    Science.gov (United States)

    Lee, André; Chadde, Mareike; Altenmüller, Eckart; Schoonderwaldt, Erwin

    2014-01-01

    Background In recent studies primary bowing tremor has been described; however, tremor frequency has never been quantitatively assessed. In addition to describing phenomenological aspects of tremor we thus aimed at assessing tremor frequency. Our hypothesis was that primary bowing tremor is similar to the phenomenological aspects and frequency of primary writing tremor. Methods We quantified primary bowing tremor in four violinists under two conditions: open strings and a G major scale. Data were analyzed using empirical mode decomposition because it takes into account non-stationarity and non-linearity of signals. For each patient we further described tremor phenomenology and assessed symptom onset, risk factors, medication, and family history with a structured anamnesis. We compare the findings to previous findings for primary bowing tremor and primary writing tremor. Results We mainly found a flexion–extension tremor of the wrist with a frequency range of 4.7–6.7 Hz. There was no significant difference between the conditions. Mean onset age was 43±2.4 years. Medication included trihexyphenidyl, propranolol, primidone, and botulinum toxin. We found a positive family history in two patients and an injury prior to symptom onset in another two patients. Comparison of onset age, frequency range, family history, and injuries prior to onset revealed that our findings are very similar to previous findings on primary bowing tremor and primary writing tremor. Discussion Our findings confirmed our hypothesis that primary bowing tremor is similar to primary writing tremor, with regard to phenomenology and epidemiology as well as tremor frequency. There was no difference in tremor frequency between conditions, suggesting that tremor is not influenced by bimanual coordination or bowing speed. Our findings thus provide new phenomenological aspects and may contribute to a better understanding of primary bowing tremor. PMID:24932423

  6. Simulation of Complex Tremor Migration Patterns

    Science.gov (United States)

    Luo, Y.; Ampuero, J. P.

    2012-12-01

    The discovery of slow-slip events (SSE) and non-volcanic tremors has greatly enriched the spectrum of earthquake behavior and offers a unique window into the mechanics of the deeper portion of the seismogenic zone of active faults, an uncharted region of great importance in the nucleation of large earthquakes. In Northern Cascadia, tremors show an intriguing hierarchy of migration patterns: large-scale tremor migrating along-strike at about 10 km/day, sparsely distributed swarms that propagate 10 times faster in the opposite direction ('rapid tremor reversals' or RTRs) and even 10 times faster swarms that propagate along-dip. Moreover, during the initial phase of ETS (Episodic Tremor and Slip) the tremor source amplitude shows a linear growth and up-dip propagation. We have proposed a model to reproduce these observations based on interaction of brittle asperities (frictionally unstable, velocity-weakening patches) embedded in a relatively stable fault, mediated by creep transients. We continue quantitative studies of this model through numerical simulations of heterogeneous rate-and-state faults under the Quasi-DYNamic approximation (open-source software project QDYN, hosted online at http://code.google.com/p/qdyn/). We performed both 2D and 3D simulations and successfully reproduced all the major phenomena of complex tremor migration patterns (forward migration, RTRs and along-dip swarms). We will show a complete analysis of friction properties and geometrical settings (i.e. asperity size, distance, etc.) that affects spatial-temporal distribution and migration velocity of tremors. Our study shows that by decreasing the distance between asperities or by increasing the value of (a-b)*sigma inside them, both RTR migration velocity and distance increase positively correlated, and the proportion of moment released seismically during the ETS increases, while the ratio of RTR versus forward tremor migration speed remains mostly the same. While the density of these deep

  7. Mapping Yakutat Subduction with Tectonic Tremor

    Science.gov (United States)

    Wech, A.

    2015-12-01

    Subduction of the Yakutat microplate (YAK) in south-central Alaska may be responsible for regional high topography, large slip during the 1964 earthquake, and the anomalous gap in arc volcanism, but the exact geodynamics and its relationship with the underlying Pacific Plate (PP) are not fully understood. Refraction data support distinct subducting layers, and both GPS and body wave tomography suggest the YAK extends from the Cook Inlet volcanoes in the west to the Wrangell volcanic field in the east. Earthquakes, however, are limited to normal faulting within the PP with an abrupt eastern boundary 80 km west of the inferred YAK edge, and more recent active source seismic data suggest subduction of one homogenous thickened oceanic plateau. Here, I perform a search for tectonic tremor to investigate the role of tremor and slow slip in the system. I scan continuous waveforms from 2007-2015 using all available data from permanent and campaign seismic stations in south-central Alaska. Using envelope cross-correlation, I detect and locate ~9,000 tectonic tremor epicenters, providing a map of the transition zone downdip of the 1964 earthquake. Tremor epicenters occur downdip of discrete slow slip events, and tremor rates do not correlate temporally with slow slip behavior. Depth resolution is poor, but horizontal locations are well constrained and spatially correlate with the velocity images of the YAK. Likewise, tremor extends 80 km further east than intraslab seismicity. Tremor swarms occur intermittently and manifest as ambient tremor. I interpret tremor to mark slow, semi-continuous slip occurring at the boundary between the YAK and North American plates, whose interface continues beyond the eastern edge of the PP. In this model, the YAK is welded to the underlying PP in the west, but extends past the eastern terminus of the PP. This geometry explains the correlation between tremor and the YAK, the discrepancy between deep seismicity and tremor, and the paucity of

  8. Development of an essential tremor embarrassment assessment.

    Science.gov (United States)

    Traub, Rebecca E; Gerbin, Marina; Mullaney, Mary M; Louis, Elan D

    2010-12-01

    Embarrassment is commonly reported in essential tremor (ET) patients yet there is no formal tool to assess embarrassment in ET. Our aim was to develop such a tool and to assess its clinimetric properties. A quantitative measure of embarrassment could be used to assess response to treatment in clinical practice and clinical trials. Based on surveys of international tremor experts and ET patients, we constructed the Essential Tremor Embarrassment Assessment (ETEA), a brief, easily administered, 14-item self-assessment scale. The ETEA was assessed for validity, reliability and other clinimetric properties in 75 ET patients. Forty-seven tremor experts from eight countries were surveyed. On average, they estimated that 75% of their patients experienced embarrassment, yet there was very little agreement (range = 10-95%). Among ET patients, three-quarters (77.3%) reported at least occasional embarrassment due to their tremor and one-third (36.4%) reported daily embarrassment. ETEA scores correlated with a tremor disability questionnaire score (p = 0.02 and p = 0.01) and Center for Epidemiologic Studies Depression Scale scores (pEmbarrassment is commonly experienced by ET patients. The ETEA is a reliable and valid tool to measure embarrassment in patients with this disease. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Model of deep non-volcanic tremor part I: ambient and triggered tremor

    CERN Document Server

    Gershenzon, Naum I

    2013-01-01

    There is evidence of triggering of tremor by seismic waves emanating from distant large earthquakes. The frequency contents of triggered and ambient tremor are largely identical, suggesting that tremor does not depend directly on the nature of the source. We show here that the model of plate dynamics developed earlier by us is an appropriate tool for describing the onset of tremor. In the framework of this model, tremor is an internal response of a fault to a failure triggered by external disturbances. The model predicts generation of radiation in a frequency range defined by the fault parameters. Other specific features predicted are: the upper limit of the size of the emitting area is a few dozen km; tremor accompanies earthquakes and aseismic slip; the frequency content of tremor depends on the type of failure. The model also explains why a tremor has no clear impulsive phase, in contrast to earthquakes. A comparatively small effective normal stress (hence a high fluid pressure) is required to make the mod...

  10. Tremor recording and analysis as a tool for target localisation in thalamotomy and DBS for tremor

    NARCIS (Netherlands)

    Journee, HL; Hamoen, DJ; Staal, MJ; Sclabassi, R; Haaxma, R; Elands, A; Hummel, JJJ; Boom, H; Robinson, C; Rutten, W; Neuman, M; Wijkstra, H

    1997-01-01

    The objective of this work was to design and use a tremor and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of

  11. Tremor recording and analysis as a tool for target localisation in thalamotomy and DBS for tremor

    NARCIS (Netherlands)

    Journee, HL; Hamoen, DJ; Staal, MJ; Sclabassi, R; Haaxma, R; Elands, A; Hummel, JJJ; Boom, H; Robinson, C; Rutten, W; Neuman, M; Wijkstra, H

    1997-01-01

    The objective of this work was to design and use a tremor and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of t

  12. Northern Cascadia episodic tremor and slip: A decade of tremor observations from 1997 to 2007

    Science.gov (United States)

    Kao, Honn; Shan, Shao-Ju; Dragert, Herb; Rogers, Garry

    2009-11-01

    We analyze continuous seismic and GPS records collected in the last decade (1997-2007) to establish the most comprehensive observational basis for northern Cascadia episodic tremor and slip (ETS) events. A simple "ETS scale" system, using a combination of a letter and a digit, is proposed to quantitatively characterize the spatial and temporal dimensions of ETS events. Clear correlation between GPS and tremor signals is observed for all A/B class episodes, but the GPS signature is less obvious for minor ones. Regular ETS recurrence can be established only for A/B class episodes in southern Vancouver Island. Halting and jumping are very common in ETS migration patterns, and along-strike migration can happen in both directions. A prominent tremor gap is observed in midisland around 49.5°N. This gap coincides with the epicenters of the only two large earthquakes beneath Vancouver Island. ETS tremors also tend to occur in places where the local seismicity is relatively sparse. The tremor depth distribution shows a peak in the 25-35 km range where strong seismic reflectors (i.e., the E layer) are documented. Detailed waveform analysis confirms the existence of shallow tremors above the currently interpreted plate interface. Our results suggest that a significant portion of the tremor activity and perhaps associated shearing are taking place along well-developed structures such as the E layer, while fewer tremor bursts are generated elsewhere in response to the induced stress variation throughout the source volume.

  13. Tectonic tremor and LFEs on a reverse fault in Taiwan: TREMOR AND LFES IN TAIWAN

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Ana C. [Lawrence Livermore National Laboratory, Livermore California USA; Geophysics Department, Stanford University, Stanford California USA; Chao, Kevin [Center for Optimization and Statistical Learning, Northwestern Institute on Complex Systems, Northwestern University, Evanston Illinois USA; Beroza, Gregory C. [Geophysics Department, Stanford University, Stanford California USA

    2017-07-06

    We compare low-frequency earthquakes (LFEs) from triggered and ambient tremor under the southern Central Range, Taiwan. We apply the PageRank algorithm used by Aguiar and Beroza (2014) that exploits the repetitive nature of the LFEs to find repeating LFEs in both ambient and triggered tremor. We use these repeaters to create LFE templates and find that the templates created from both tremor types are very similar. To test their similarity, we use both interchangeably and find that most of both the ambient and triggered tremor match the LFE templates created from either data set, suggesting that LFEs for both events have a common origin. We locate the LFEs by using local earthquake P wave and S wave information and find that LFEs from triggered and ambient tremor locate to between 20 and 35 km on what we interpret as the deep extension of the Chaochou-Lishan Fault.

  14. A review of primary writing tremor.

    Science.gov (United States)

    Rana, Abdul Qayyum; Vaid, Haris M

    2012-03-01

    A task-specific tremor (TST) is a rare form of movement disorder that appears while performing or attempting to perform a particular task. Primary writing tremor (PWT) is the most common form of TST which only occurs during the act of writing and hinders it. (Bain PG, Findley LJ, Britton TC, Rothwell JC, Gresty MA, Thompson PD, Marsden CD. MRC Human Movement, and Balance Unit, Institute of Neurology, London, UK. Primary writing tremor. Brain. 1995;118(6):1461-72.) Primary writing tremor type B is present not only during the act of writing but also when the hand assumes a writing posture. (Bain PG, Findley LJ, Britton TC, Rothwell JC, Gresty MA, Thompson PD, Marsden CD. MRC Human Movement and Balance Unit, Institute of Neurology, London, UK. Primary writing tremor. Brain. 1995;118(6):1461-72.) We first of all describe a remarkable case study of a 50-year old, right-handed male who started experiencing a primary writing tremor in his right hand about a year ago. This case was found to be of particular interest because the patient had it relatively difficult when attempting to write numbers as opposed to writing letters. This review further discusses the clinical manifestations of PWT. In addition, three main hypotheses have been proposed for the causation of PWT, although the exact pathophysiology of PWT still remains unknown. It has been suggested that PWT is a separate entity, a variant of essential tremor and not a separate entity, or a type of dystonia. The various treatment options for PWT are discussed including botulinum toxin and oral pharmacotherapy.

  15. Comparison of mortality following hospitalisation for isolated head injury in England and Wales, and Victoria, Australia.

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    Belinda J Gabbe

    Full Text Available BACKGROUND: Traumatic brain injury (TBI remains a leading cause of death and disability. The National Institute for Health and Clinical Excellence (NICE guidelines recommend transfer of severe TBI cases to neurosurgical centres, irrespective of the need for neurosurgery. This observational study investigated the risk-adjusted mortality of isolated TBI admissions in England/Wales, and Victoria, Australia, and the impact of neurosurgical centre management on outcomes. METHODS: Isolated TBI admissions (>15 years, July 2005-June 2006 were extracted from the hospital discharge datasets for both jurisdictions. Severe isolated TBI (AIS severity >3 admissions were provided by the Trauma Audit and Research Network (TARN and Victorian State Trauma Registry (VSTR for England/Wales, and Victoria, respectively. Multivariable logistic regression was used to compare risk-adjusted mortality between jurisdictions. FINDINGS: Mortality was 12% (749/6256 in England/Wales and 9% (91/1048 in Victoria for isolated TBI admissions. Adjusted odds of death in England/Wales were higher compared to Victoria overall (OR 2.0, 95% CI: 1.6, 2.5, and for cases <65 years (OR 2.36, 95% CI: 1.51, 3.69. For severe TBI, mortality was 23% (133/575 for TARN and 20% (68/346 for VSTR, with 72% of TARN and 86% of VSTR cases managed at a neurosurgical centre. The adjusted mortality odds for severe TBI cases in TARN were higher compared to the VSTR (OR 1.45, 95% CI: 0.96, 2.19, but particularly for cases <65 years (OR 2.04, 95% CI: 1.07, 3.90. Neurosurgical centre management modified the effect overall (OR 1.12, 95% CI: 0.73, 1.74 and for cases <65 years (OR 1.53, 95% CI: 0.77, 3.03. CONCLUSION: The risk-adjusted odds of mortality for all isolated TBI admissions, and severe TBI cases, were higher in England/Wales when compared to Victoria. The lower percentage of cases managed at neurosurgical centres in England and Wales was an explanatory factor, supporting the changes made to the NICE

  16. Transducer-based evaluation of tremor.

    Science.gov (United States)

    Haubenberger, Dietrich; Abbruzzese, Giovanni; Bain, Peter G; Bajaj, Nin; Benito-León, Julián; Bhatia, Kailash P; Deuschl, Günther; Forjaz, Maria João; Hallett, Mark; Louis, Elan D; Lyons, Kelly E; Mestre, Tiago A; Raethjen, Jan; Stamelou, Maria; Tan, Eng-King; Testa, Claudia M; Elble, Rodger J

    2016-09-01

    The International Parkinson and Movement Disorder Society established a task force on tremor that reviewed the use of transducer-based measures in the quantification and characterization of tremor. Studies of accelerometry, electromyography, activity monitoring, gyroscopy, digitizing tablet-based measures, vocal acoustic analysis, and several other transducer-based methods were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and responsiveness were reviewed for each measure using the following criteria: (1) used in the assessment of tremor; (2) used in published studies by people other than the developers; and (3) adequate clinimetric testing. Accelerometry, gyroscopy, electromyography, and digitizing tablet-based measures fulfilled all three criteria. Compared to rating scales, transducers are far more sensitive to changes in tremor amplitude and frequency, but they do not appear to be more capable of detecting a change that exceeds random variability in tremor amplitude (minimum detectable change). The use of transducer-based measures requires careful attention to their limitations and validity in a particular clinical or research setting. © 2016 International Parkinson and Movement Disorder Society.

  17. The central oscillatory network of orthostatic tremor.

    Science.gov (United States)

    Muthuraman, Muthuraman; Hellriegel, Helge; Paschen, Steffen; Hofschulte, Frank; Reese, Rene; Volkmann, Jens; Witt, K; Deuschl, G; Raethjen, Jan

    2013-09-01

    Orthostatic tremor (OT) is a movement disorder of the legs and trunk that is present in the standing position but typically absent when sitting. The pathological central network involved in orthostatic tremor is still unknown. In this study we analyzed 15 patients with simultaneous high-resolution electroencephalography and electromyography recording to assess corticomuscular coherence. In 1 patient we were able to simultaneously record the local field potential in the ventrolateral thalamus and electroencephalography. Dynamic imaging of coherent source analysis was used to find the sources in the brain that are coherent with the peripheral tremor signal. When standing, the network for the tremor frequency consisted of unilateral activation in the primary motor leg area, supplementary motor area, primary sensory cortex, two prefrontal/premotor sources, thalamus, and cerebellum for the whole 30-second segment recorded. The source coherence dynamics for the primary leg area and the thalamic source signals with the tibialis anterior muscle showed that they were highly coherent for the whole 30 seconds for the contralateral side but markedly decreased after 15 seconds for the ipsilateral side. The source signal and the recorded thalamus signal followed the same time frequency dynamics of coherence in 1 patient. The corticomuscular interaction in OT follows a consistent pattern with an initially bilateral pattern and then a segregated unilateral pattern after 15 seconds. This may add to the feeling of unsteadiness. It also makes the thalamus unlikely as the main source of orthostatic tremor. © 2013 International Parkinson and Movement Disorder Society.

  18. Familial cortical tremor with epilepsy and cerebellar pathological findings

    NARCIS (Netherlands)

    van Rootselaar, AF; Aronica, E; Steur, ENHJ; Rozemuller-Kwakkel, JM; de Vos, RAI; Tijssen, MAJ

    The clinical and neuropathological findings in a patient with familial cortical tremor with epilepsy (FCTE) are described. Clinically, the patient showed cortical myoclonus, tremor, and generalized seizures. Pathological investigation showed cerebellar degeneration and somal sprouting and loss of

  19. Kinetic tremor: differences between smokers and non-smokers.

    Science.gov (United States)

    Louis, Elan D

    2007-05-01

    Tremor is among the acute effects of nicotine exposure. Published studies have focused on smoking-related postural (static) hand tremor rather than kinetic tremor (tremor during hand use), and gender differences in smoking-related tremor have not been examined. In a group of adults who were sampled from a population (mean+/-S.D.=65.7+/-11.5 years, range=18-92 years), the investigator assessed whether the severity of postural and kinetic tremors differed in smokers versus non-smokers, and whether this difference was influenced by gender. Twenty-seven (9.9%) of 273 subjects were current smokers. Greater tremor was observed in smokers than non-smokers during a variety of activities (drawing a spiral, using a spoon, finger-nose-finger maneuver, all phabits should be considered carefully in order to avoid over- or underestimating the effects of occupational and non-occupational exposures to other tremor-producing neurotoxins.

  20. The Clinical Evaluation of Parkinson’s Tremor

    Science.gov (United States)

    Zach, Heidemarie; Dirkx, Michiel; Bloem, Bastiaan R.; Helmich, Rick C.

    2015-01-01

    Abstract Parkinson’s disease harbours many different tremors that differ in distribution, frequency, and context in which they occur. A good clinical tremor assessment is important for weighing up possible differential diagnoses of Parkinson’s disease, but also to measure the severity of the tremor as a basis for further tailored treatment. This can be challenging, because Parkinson’s tremor amplitude is typically very variable and context-dependent. Here, we outline how we investigate Parkinson’s tremor in the clinic. We describe a simple set of clinical tasks that can be used to constrain tremor variability (cognitive and motor co-activation, several specific limb postures). This may help to adequately characterize the tremor(s) occurring in a patient with Parkinson’s disease. PMID:26406126

  1. Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS)

    Science.gov (United States)

    ... Resources and Publications Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS): Overview Skip sharing on social media ... this: Page Content Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset condition (occurs ...

  2. Aseismic moment release associated with rapid tremor reversals in Cascadia

    Science.gov (United States)

    Hawthorne, J. C.; Bostock, M. G.; Royer, A. A.; Thomas, A.; Savard, G.

    2015-12-01

    We identify variations in slow slip moment rate associated with rapid tremor reversals (RTRs) beneath Vancouver Island, in Cascadia. The RTRs were identified by Royer et. al., 2015 with their high-quality tremor catalog based on low frequency earthquakes. In most of them, tremor propagates a few tens of kilometers over a few hours. We use PBO borehole strain data to search for aseismic moment rate variations associated with the reversals. We isolate components of strain that have high signal to noise ratios by avoiding components that have a strong response to atmospheric pressure. In the corrected strain data, the strain rate is systematically higher during the RTRs than during the 4 days surrounding them. On average, the strain rate increases by a factor of 2 during the reversals.This factor of 2 increase in strain rate can be roughly interpreted as a factor of 2 increase in moment rate. The location of slip moves by just a few tens of kilometers during the 4-day periods of interest, so the Green's functions do not change dramatically. If we scale this moment rate by the moment rate of the slow slip event, and account for the RTR durations, we estimate that each reversal releases a moment similar to that in a M 5 earthquake. If the along-dip width of the reversals is comparable to the width of the whole slow slip event, the estimated moment implies a stress drop of order 1 kPa. This is comparable to the tidal stresses and less than 10% of the slow slip stress drop. If the along-dip width of the RTRs is smaller---say 20 km---the aseismic moment implies a stress drop of order 5 kPa, only a factor of a few smaller than the slow slip stress drop.

  3. Dopamine controls Parkinson's tremor by inhibiting the cerebellar thalamus.

    Science.gov (United States)

    Dirkx, Michiel F; den Ouden, Hanneke E M; Aarts, Esther; Timmer, Monique H M; Bloem, Bastiaan R; Toni, Ivan; Helmich, Rick C

    2017-01-09

    Parkinson's resting tremor is related to altered cerebral activity in the basal ganglia and the cerebello-thalamo-cortical circuit. Although Parkinson's disease is characterized by dopamine depletion in the basal ganglia, the dopaminergic basis of resting tremor remains unclear: dopaminergic medication reduces tremor in some patients, but many patients have a dopamine-resistant tremor. Using pharmacological functional magnetic resonance imaging, we test how a dopaminergic intervention influences the cerebral circuit involved in Parkinson's tremor. From a sample of 40 patients with Parkinson's disease, we selected 15 patients with a clearly tremor-dominant phenotype. We compared tremor-related activity and effective connectivity (using combined electromyography-functional magnetic resonance imaging) on two occasions: ON and OFF dopaminergic medication. Building on a recently developed cerebral model of Parkinson's tremor, we tested the effect of dopamine on cerebral activity associated with the onset of tremor episodes (in the basal ganglia) and with tremor amplitude (in the cerebello-thalamo-cortical circuit). Dopaminergic medication reduced clinical resting tremor scores (mean 28%, range -12 to 68%). Furthermore, dopaminergic medication reduced tremor onset-related activity in the globus pallidus and tremor amplitude-related activity in the thalamic ventral intermediate nucleus. Network analyses using dynamic causal modelling showed that dopamine directly increased self-inhibition of the ventral intermediate nucleus, rather than indirectly influencing the cerebello-thalamo-cortical circuit through the basal ganglia. Crucially, the magnitude of thalamic self-inhibition predicted the clinical dopamine response of tremor. Dopamine reduces resting tremor by potentiating inhibitory mechanisms in a cerebellar nucleus of the thalamus (ventral intermediate nucleus). This suggests that altered dopaminergic projections to the cerebello-thalamo-cortical circuit have a role

  4. Tremor da escrita: relato de caso

    Directory of Open Access Journals (Sweden)

    Denise Hack Nicaretta

    1994-03-01

    Full Text Available O tremor da escrita é distúrbio precipitado por atividade motora específica, geralmente a escrita. Analisamos este caso sob o ponto de vista clínico e terapêutico. O paciente apresentava tremor ao escrever tomando sua letra ilegível; sem qualquer outra alteração neurológica. Não havia antecedentes familiares, metabólicos, endócrinos, iatrogênicos, tóxicos ou traumáticos. No manuseio terapêutico não ocorreu resposta satisfatória ao propranolol, sendo discreta à primidona. A introdução de anticolinérgicos (tri-hexifenidil evidenciou certa melhora na sintomatologia, com redução do tremor no momento da escrita.

  5. Hypothetical membrane mechanisms in essential tremor

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    Ramat Stefano

    2008-11-01

    Full Text Available Abstract Background Essential tremor (ET is the most common movement disorder and its pathophysiology is unknown. We hypothesize that increased membrane excitability in motor circuits has a key role in the pathogenesis of ET. Specifically, we propose that neural circuits controlling ballistic movements are inherently unstable due to their underlying reciprocal innervation. Such instability is enhanced by increased neural membrane excitability and the circuit begins to oscillate. These oscillations manifest as tremor. Methods Postural limb tremor was recorded in 22 ET patients and then the phenotype was simulated with a conductance-based neuromimetic model of ballistic movements. The model neuron was Hodgkin-Huxley type with added hyperpolarization activated cation current (Ih, low threshold calcium current (IT, and GABA and glycine mediated chloride currents. The neurons also featured the neurophysiological property of rebound excitation after release from sustained inhibition (post-inhibitory rebound. The model featured a reciprocally innervated circuit of neurons that project to agonist and antagonist muscle pairs. Results Neural excitability was modulated by changing Ih and/or IT. Increasing Ih and/or IT further depolarized the membrane and thus increased excitability. The characteristics of the tremor from all ET patients were simulated when Ih was increased to ~10× the range of physiological values. In contrast, increasing other membrane conductances, while keeping Ih at a physiological value, did not simulate the tremor. Increases in Ih and IT determined the frequency and amplitude of the simulated oscillations. Conclusion These simulations support the hypothesis that increased membrane excitability in potentially unstable, reciprocally innervated circuits can produce oscillations that resemble ET. Neural excitability could be increased in a number of ways. In this study membrane excitability was increased by up-regulating Ih and IT. This

  6. Unilateral rubral tremors in Wilson′s disease treated with dimercaprol

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    Rahul T Chakor

    2015-01-01

    Full Text Available Tremors are reported as the most frequent neurological manifestation of Wilson′s disease (WD in some series. Postural tremors, rest tremors, action tremors and wing-beating (rubral tremors are the different types of tremors seen in WD. We report a patient of WD with unilateral rubral tremors refractory to 1-year therapy with Penicillamine and anti-tremor medications. The tremors decreased considerably after adding chelation therapy with dimercaprol. Combination of Penicillamine and dimercaprol is an effective decoppering measure in rubral tremors of WD.

  7. Comparing Moment Release and Tremor Amplitudes in Cascadia ETS Events

    Science.gov (United States)

    Hall, K.; Schmidt, D. A.; Houston, H.

    2016-12-01

    A proposed relationship between the moment release of ETS and tremor duration. [Aguiar et al., 2009] compared moment from static inversions of slip with the overall duration of the entire ETS, finding a linear relationship between moment release and tremor duration. There is a logical relationship between the processes that generate slip and those that generate tremor. Spatially, we have seen that slip may occur up-dip of tremor [Houston, 2012] and [Hall and Houston, 2014] in Northern Cascadia. On the other hand, Bartlow et al. [2011] did not resolve a spatio-temporal difference between tremor and slow slip for the 2009 ETS in mid-Cascadia. This raises the possibility that there could be an as-yet-unrecognized regional difference. In order to explore spatio-temporal relationships between tremor and slow slip, I used the Extended Network Inversion Filter (ENIF) [Segall and Matthews, 1997] together with PNSN tremor locations. Preliminary results for the 2010 ETS event yield a M6.8 event that begins near Seattle on August 8th and propagates mainly to the north with some smaller slip to the south, following the propagation of the tremor, a pattern consistent with our static inversion results. The slip-pulse nature of the ETS process is clearly imaged, with some fault patches continuing to slip for several days after tremor has passed through, but not for the entire duration of the event. I then looked at tremor amplitudes [Ulberg and Creager, AGU Abs, 2013], which represent the amount of energy released in a five-minute tremor window. Because the tremor catalog has much finer temporal resolution than the GPS data, I sum the daily tremor amplitudes and compare to daily moment-rates from the time-dependent inversion, obtaining a correlation between moment-rate and tremor amplitude rate. This suggests that the energy released by tremor may be a direct proxy for energy released by slip.

  8. Diagnóstico diferencial dos tremores Differential diagnosis of tremors

    Directory of Open Access Journals (Sweden)

    JAMES PITÁGORAS DE MATTOS

    1998-06-01

    Full Text Available Baseado na revisão da literatura, o autor refere-se aos tremores normal (fisiológico e anormal (patológico. Analisa particularmente os patológicos, dividindo-os em de repouso e de ação. Com os elementos semiológicos estabelece o diagnóstico diferencial entre os tremores parkinsoniano, essencial severo, rubral, tardio, postural, cinético e os de posição e de ação específica, entre outros.After the review of the literature the author presents the semiologic basis for the differential diagnosis of rest and action tremors. The parkinsonian, severe essential, rubral, tardive, postural, kinetic and the task or position-specific tremors are mainly analysed.

  9. Dramatic response to levetiracetam in post-ischaemic Holmes’ tremor

    Science.gov (United States)

    Striano, P; Elefante, Andrea; Coppola, Antonietta; Tortora, Fabio; Zara, Federico; Minetti, Carlo

    2009-01-01

    Holmes’ tremor refers to an unusual combination of rest, postural and kinetic tremor of extremities. Common causes of Holmes’ tremor include stroke, trauma, vascular malformations and multiple sclerosis, with lesions involving the thalamus, brain stem or cerebellum. Although some drugs (eg, levodopa and dopaminergic drugs, clonazepam and propranolol) have been occasionally reported to give some benefit, medical treatment of Holmes’ tremor is unsatisfactory, and many patients require thalamic surgery to achieve satisfactory control. We report a patient in whom post-ischaemic Holmes’ tremor dramatically responded to levetiracetam treatment. PMID:21686707

  10. Interpersonal relationships in isolation and confinement: Long-term bed rest in head-down tilt position

    Science.gov (United States)

    Karine, Weiss; Gabriel, Moser

    The long-term bed-rest was organized by ESA and CNES, in order to simulate the physiological effects of weightlessness: eight volunteers had to stay 42 days in bed, in a head down tilt position (-6 °). There were two subjects in a room, they could not be alone and it was difficult for them to have their own personal space and intimacy. In these circumstances, as in outer space, interpersonal relationships were of prime importance. This situation enabled us, through systematic observation, to analyze the evolution of the relational behavior in dyads, and to quote some social indicators of adaptation. Results show significant withdrawal, and the time spent alone was marked by the emergence, during the experiment, of specific preferential activities. Behavioral contagion was observed in each dyad (people engaged in the same activities at the same time), except in the one case of abandon. Moreover, the highest rates of inactivity and withdrawal were noted in this case. Verbal indicators were useful to comment these results and showed that, for all the dyads, one of the two subjects always played a regulating role by expressing a very positive perception of the situation. These results emphasize the importance of psycho-sociological factors in isolation and confinement. Thus, it appears that different modalities of interpersonal relationships, and not only verbal interactions, play a significant role in adaptation to stress situations.

  11. Facial emotion recognition is inversely correlated with tremor severity in essential tremor.

    Science.gov (United States)

    Auzou, Nicolas; Foubert-Samier, Alexandra; Dupouy, Sandrine; Meissner, Wassilios G

    2014-04-01

    We here assess limbic and orbitofrontal control in 20 patients with essential tremor (ET) and 18 age-matched healthy controls using the Ekman Facial Emotion Recognition Task and the IOWA Gambling Task. Our results show an inverse relation between facial emotion recognition and tremor severity. ET patients also showed worse performance in joy and fear recognition, as well as subtle abnormalities in risk detection, but these differences did not reach significance after correction for multiple testing.

  12. De fysiologische tremor van de hand

    NARCIS (Netherlands)

    Weerden, Tiemen Willem van

    1989-01-01

    Bij het innemen van een houding, zoals het willekeurig horizontaal gestrekt houden van de hand, vertoont het betrokken lichaamsdeel kleine fluctuaties in positie: de fysiologische tremor. Het doel van het proefschrift is, naast een beschrijving van het fenomeen, inzicht te geven in de oorzakelijke f

  13. Differences in striatal dopamine transporter density between tremor dominant and non-tremor Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Kaasinen, Valtteri; Kinos, Maija; Joutsa, Juho [University of Turku and Turku University Hospital, Division of Clinical Neurosciences, Turku (Finland); University of Turku and Turku University Hospital, Turku PET Centre, Turku (Finland); Seppaenen, Marko [University of Turku and Turku University Hospital, Turku PET Centre, Turku (Finland); University of Turku and Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku (Finland); Noponen, Tommi [University of Turku and Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku (Finland)

    2014-10-15

    Parkinson's disease (PD) can manifest with a tremor-dominant or a non-tremor (akinetic-rigid) phenotype. Although the tremor-dominant subtype may show a better prognosis, there is limited information on the phenotypic differences regarding the level of striatal dopamine transmission. The present study investigated striatal dopamine transporter (DAT) binding characteristics in a large sample of patients with and without tremor. [{sup 123}I]FP-CIT SPECT scans of 231 patients with a clinical diagnosis of PD and abnormal FP-CIT binding (157 with tremor, 74 without tremor) and 230 control patients with normal FP-CIT binding (148 with tremor, 82 without tremor) were analysed using an automated region-of-interest analysis of the scans (BRASS). Specific striatal binding ratios were compared between phenotypes and groups using age, sex, and symptom duration, predominant side of symptoms, dopaminergic medications and scanner as covariates. Patients with PD had 28.1 - 65.0 % lower binding in all striatal regions compared to controls (p < 0.001). The mean FP-CIT caudate nucleus uptake and the left caudate nucleus uptake were higher in PD patients with tremor than in PD patients without tremor (mean 9.0 % higher, left 10.5 % higher; p < 0.05), whereas there were no differences between tremor and non-tremor control patients. No significant effects of tremor on DAT binding were observed in the anterior or posterior putamen. The motor phenotype is associated with the extent of caudate dopamine terminal loss in PD, as dopamine function is relatively more preserved in tremor patients. Symptom type is related to caudate dopamine function only in association with Parkinsonian dopaminergic degeneration, not in intact dopamine systems in patients with non-PD tremor. (orig.)

  14. Tactile and proprioceptive temporal discrimination are impaired in functional tremor.

    Directory of Open Access Journals (Sweden)

    Michele Tinazzi

    Full Text Available In order to obtain further information on the pathophysiology of functional tremor, we assessed tactile discrimination threshold and proprioceptive temporal discrimination motor threshold values in 11 patients with functional tremor, 11 age- and sex-matched patients with essential tremor and 13 healthy controls.Tactile discrimination threshold in both the right and left side was significantly higher in patients with functional tremor than in the other groups. Proprioceptive temporal discrimination threshold for both right and left side was significantly higher in patients with functional and essential tremor than in healthy controls. No significant correlation between discrimination thresholds and duration or severity of tremor was found.Temporal processing of tactile and proprioceptive stimuli is impaired in patients with functional tremor. The mechanisms underlying this impaired somatosensory processing and possible ways to apply these findings clinically merit further research.

  15. Model for triggering of non-volcanic tremor by earthquakes

    CERN Document Server

    Gershenzon, Naum I

    2012-01-01

    There is evidence of tremor triggering by seismic waves emanating from distant large earthquakes. The frequency content of both triggered and ambient tremor are largely identical, suggesting that this property does not depend directly on the nature of the source. We show here that the model of plate dynamics developed earlier by us is an appropriate tool for describing tremor triggering. In the framework of this model, tremor is an internal response of a fault to a failure triggered by external disturbances. The model predicts generation of radiation in a frequency range defined by the fault parameters. Thus, although the amplitude and duration of a tremor burst may reflect the "personality" of the source, the frequency content does not. The model also explains why a tremor has no clear impulsive phase, in contrast to earthquakes. The relationship between tremor and low frequency earthquakes is discussed.

  16. Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits?

    NARCIS (Netherlands)

    Helmich, R.C.G.; Hallett, M.; Deuschl, G.; Toni, I.; Bloem, B.R.

    2012-01-01

    Tremor in Parkinson's disease has several mysterious features. Clinically, tremor is seen in only three out of four patients with Parkinson's disease, and tremor-dominant patients generally follow a more benign disease course than non-tremor patients. Pathophysiologically, tremor is linked to

  17. Observations of two special kinds of tremor at Galeras volcano, Colombia (1989-1991)

    Energy Technology Data Exchange (ETDEWEB)

    Gil Cruz, F. [Observatorio Vulcanologico y Sismologico, Manizales (Colombia)

    1999-06-01

    The paper analyzes two kinds of tremor produced by Galeras volcano in 1988: flute tremor and spasmodic tremor. Spectrum and peak of flute tremor are described. The paper also distinguishes two types of spasmodic tremor on the basis of their spectral characteristics and field observations.

  18. Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits?

    NARCIS (Netherlands)

    Helmich, R.C.G.; Hallett, M.; Deuschl, G.; Toni, I.; Bloem, B.R.

    2012-01-01

    Tremor in Parkinson's disease has several mysterious features. Clinically, tremor is seen in only three out of four patients with Parkinson's disease, and tremor-dominant patients generally follow a more benign disease course than non-tremor patients. Pathophysiologically, tremor is linked to altere

  19. Quantifying tectonic tremor in southern Mexico and its curious relationship to slow slip and other tremor triggers

    Science.gov (United States)

    Sit, S. M.; Brudzinski, M. R.

    2011-12-01

    The discoveries of tectonic tremor along with slow slip provide exciting new insights into fault deformation at major tectonic boundaries. Tremor and slip were first recorded in Cascadia, but have now been observed in a variety of other subduction zones. Recent studies in Oaxaca, Mexico reveal both slow slip and tectonic tremor, but analysis of the most prominent tremor finds it occurs over a short time period of 2-10 days and recurs as often as every 2-3 months, while slow slip occurs much less frequently on the order of 12-24 months. This result was surprising considering that tremor and slip are so well correlated in Cascadia that a linear relationship exists between the number of tremor hours recorded and the moment of concurrent slow slip. In contrast, the first study of tremor in Oaxaca found prominent tremor episodes were only slightly more common during the 2-month slow slip event than the 6 months before or after. However, tremor is more difficult to detect in Oaxaca than Cascadia considering the frequent regional seismicity, seasonal storms, and limited seismic network. Here, we use our detection algorithm to investigate the prevalence of short period tremor, which may have gone undetected by the original processing of scanning 4-day average absolute amplitudes in the tremor passband. As an alternative, we utilize a recently developed technique for detecting tremor that takes advantage of the narrow frequency content by calculating the ratio of amplitudes in the tremor passband relative to amplitudes in higher and lower frequency passbands where regional seismicity and surface waves are more common, respectively. Results from this frequency ratio method are in good agreement with the original tremor detections and locations in Oaxaca and additionally, detect several previously unidentified low amplitude, short duration inter-ETS tremor events. Moreover, this detection technique will provide a more thorough estimate of tremor prevalence over time to test

  20. Cosmic signatures in earth's seismic tremor?

    Science.gov (United States)

    Mulargia, Francesco

    2017-01-01

    Even in absence of earthquakes, each site on earth experiences continuous elastic vibrations which are mostly traced to the nonlinear interactions of ocean waves. However, the fine structure of the spectrum at mHz frequencies shows many persistent and highly significant narrow bandwidth peaks in surprising coincidence with solar acoustic eigenmodes. The feasibility of a common cosmic origin is evaluated through an estimate of the gravitational wave cross-section of the earth, combined with its elastic response and with the stochastic amplification produced by the interference of the cosmic signal with tremor of oceanic origin. The measured spectral peaks appear compatible with a gravitational monochromatic illumination at strains h ≳ 10-20, larger than those expected for any known gravitational stellar source. Hence, a gravitational source attribution to the tremor spectral peaks would call for a population of unknown non-luminous sources with well-defined mass-distance ratios.

  1. [Topiramate in the treatment of essential tremor].

    Science.gov (United States)

    Zalialova, Z A; Latypova, G R

    2008-01-01

    Therapeutic efficacy of topiramate in essential tremor (ET) was assessed in comparison with propranolol in two groups which included 24 and 20 patients, respectively, aged from 21 to 83 years (mean age 53 years). Along with clinical examination, a number of scales: Clinical rating scale for tremor, scale of functional disturbances and Visual-analogous scale have been administered. The efficacy of topiramate was comparable to that of propranolol in 83% and 75% cases, respectively. However topiramate has some therapeutic advantages compared to propranolol; it may be prescribed for all clinical forms regardless of sex (its efficacy is higher in women), age and illness duration, both in earlier and later onset, familial and sporadic variants of ET (propranolol is more effective in patients with family history of ET). Moreover, in contrast to propranolol, topiramate may be prescribed to patients with predisposition to arterial hypertension and bradicardia, bronchial spasms of diabetes mellitus and heart rhythm disturbances.

  2. Nonvolcanic tremors in the Mexican subduction zone

    Science.gov (United States)

    Payero, J. S.; Kostoglodov, V.; Mikumo, T.; Perez-Campos, X.; Iglesias, A.; Clayton, R.

    2007-05-01

    Nonvolcanic low frequency tremors (NVT) have been discovered and studied recently in Japan and Cascadia subduction zones and deep beneath the San Andreas Fault. The tremors activity is increasing during so-called silent earthquakes (SQ) in Japan and Cascadia. NVT clusters also migrate following the propagation of the SQ. The origin of the NVT is still unclear. The studies of NVT and SQ in different subduction zones are required to understand the cause for these phenomena. We discovered a number of NVT from daily spectrograms of continuous broad band records at seismic stations of Servicio Seismológico Nacional (SSN) an MASE project. The analyzed data cover a period of 2001-2004 (SSN) when in 2002 a large SQ has occurred in the Guerrero- Oaxaca region, and a steady-state interseismic epoch of 2005 and a new large SQ in 2006 (MASE). NVT occurred in the central part of the Mexican subduction zone (Guerrero) at approximately 200 km from the coast. We can not accurately localize the tremors because of sparse station coverage in 2001-2004. The MASE data of 2005-2006 show that NVT records in Mexico are very similar to those obtained in Cascadia subduction zone. The tremors duration is of 10-60 min, and they appear to travel at S-wave velocities. More than 100 strong NVT were recorded by most of the MASE stations with the epicenters clustered in the narrow band of ~40x150 km to the south of Iguala city and parallel to the coast line. NVT depths are poorly constrained but seem to be less than 40 km deep. We noticed a some increase of NVT activity during the 2001-2002 and 2006 SQs compared with an NVT activity for the "SQ quiet" period of 2003-2004 nevertheless. A lack of NVT for the period of 2-3 months after the SQ is apparent in 2002 and 2006.

  3. Spatial and temporal patterns of nonvolcanic tremor along the southern Cascadia subduction zone

    Science.gov (United States)

    Boyarko, Devin C.; Brudzinski, Michael R.

    2010-08-01

    Episodic tremor and slip (ETS), the spatial and temporal correlation of slow slip events monitored via GPS surface displacements and nonvolcanic tremor (NVT) monitored via seismic signals, is a newly discovered mode of deformation thought to be occurring downdip from the seismogenic zone along several subduction zone megathrusts. To provide overall constraints on the distribution and migration behavior of NVT in southern Cascadia, we apply a semiautomated location algorithm to seismic data available during the EarthScope Transportable Array deployment to detect the most prominent pulses of NVT and invert analyst-refined relative arrival times for source locations. In the processing, we also detect distinct and isolated bursts of energy within the tremor similar to observations of low-frequency earthquakes in southwest Japan. We investigate in detail eight NVT episodes between November 2005 and August 2007 with source locations extending over a 650 km along-strike region from northern California to northern Oregon. We find complex tremor migration patterns with periods of steady migration (4-10 km/d), halting, and frequent along-strike jumps (30-400 km) in activity. The initiation and termination points of laterally continuous tremor activity appear to be repeatable features between NVT episodes which support the hypothesis of segmentation within the ETS zone. The overall distribution of NVT epicenters occur within a narrow band primarily confined by the surface projections of the 30 and 40 km contours of the subducting plate interface. We find as much as 50 km spatial offset from the updip edge of the tremor source zone to the downdip edge of the thermally and geodetically defined transition zone, which may inhibit ETS from triggering earthquakes further updip. Intriguingly, NVT activity is spatially anticorrelated with local seismicity, suggesting the two processes are mutually exclusive. We propose that the transition in frictional behavior coupled with high pore

  4. Brittle and ductile friction and the physics of tectonic tremor

    Science.gov (United States)

    Daub, E.G.; Shelly, D.R.; Guyer, R.A.; Johnson, P.A.

    2011-01-01

    Observations of nonvolcanic tremor provide a unique window into the mechanisms of deformation and failure in the lower crust. At increasing depths, rock deformation gradually transitions from brittle, where earthquakes occur, to ductile, with tremor occurring in the transitional region. The physics of deformation in the transition region remain poorly constrained, limiting our basic understanding of tremor and its relation to earthquakes. We combine field and laboratory observations with a physical friction model comprised of brittle and ductile components, and use the model to provide constraints on the friction and stress state in the lower crust. A phase diagram is constructed that characterizes under what conditions all faulting behaviors occur, including earthquakes, tremor, silent transient slip, and steady sliding. Our results show that tremor occurs over a range of ductile and brittle frictional strengths, and advances our understanding of the physical conditions at which tremor and earthquakes take place. Copyright ?? 2011 by the American Geophysical Union.

  5. Multistep prediction of physiological tremor for surgical robotics applications.

    Science.gov (United States)

    Veluvolu, Kalyana C; Tatinati, Sivanagaraja; Hong, Sun-Mog; Ang, Wei Tech

    2013-11-01

    Accurate canceling of physiological tremor is extremely important in robotics-assisted surgical instruments/procedures. The performance of robotics-based hand-held surgical devices degrades in real time due to the presence of phase delay in sensors (hardware) and filtering (software) processes. Effective tremor compensation requires zero-phase lag in filtering process so that the filtered tremor signal can be used to regenerate an opposing motion in real time. Delay as small as 20 ms degrades the performance of human-machine interference. To overcome this phase delay, we employ multistep prediction in this paper. Combined with the existing tremor estimation methods, the procedure improves the overall accuracy by 60% for tremor estimation compared to single-step prediction methods in the presence of phase delay. Experimental results with developed methods for 1-DOF tremor estimation highlight the improvement.

  6. Neurological tremor: sensors, signal processing and emerging applications.

    Science.gov (United States)

    Grimaldi, Giuliana; Manto, Mario

    2010-01-01

    Neurological tremor is the most common movement disorder, affecting more than 4% of elderly people. Tremor is a non linear and non stationary phenomenon, which is increasingly recognized. The issue of selection of sensors is central in the characterization of tremor. This paper reviews the state-of-the-art instrumentation and methods of signal processing for tremor occurring in humans. We describe the advantages and disadvantages of the most commonly used sensors, as well as the emerging wearable sensors being developed to assess tremor instantaneously. We discuss the current limitations and the future applications such as the integration of tremor sensors in BCIs (brain-computer interfaces) and the need for sensor fusion approaches for wearable solutions.

  7. Best-basis analysis of broadband tremor signals

    Directory of Open Access Journals (Sweden)

    P. Steffen

    1999-06-01

    Full Text Available Active volcanoes usually generate highly non-stationary broadband tremor signals. Short-time shock events with a frequency content of several decades are superimposed on a stationary narrow band continuous tremor. Tremor signals of this type can be observed in the near field of many active volcanoes. In this paper we will demonstrate the analysis of such signals using a specific tremor signal of Mt. Stromboli (Sicily. We used the Best-Basis Algorithm (BBA in order to compute a spectrogram which is adapted to signal properties on highly different scales. It turns out that the BBA can reveal better fitting properties of the tremor in the time-frequency plane compared to standard methods like Short-Time Fourier Transformation (STFT. Moreover, this very effective algorithm can be used for real time monitoring in the time-frequency plane, for data compression or for de-noising of the tremor signals.

  8. Genetics of Parkinson disease and essential tremor.

    Science.gov (United States)

    Wider, Christian; Ross, Owen A; Wszolek, Zbigniew K

    2010-08-01

    Elucidating the genetic background of Parkinson disease and essential tremor is crucial to understand the pathogenesis and improve diagnostic and therapeutic strategies. A number of approaches have been applied including familial and association studies, and studies of gene expression profiles to identify genes involved in susceptibility to Parkinson disease. These studies have nominated a number of candidate Parkinson disease genes and novel loci including Omi/HtrA2, GIGYF2, FGF20, PDXK, EIF4G1 and PARK16. A recent notable finding has been the confirmation for the role of heterozygous mutations in glucocerebrosidase (GBA) as risk factors for Parkinson disease. Finally, association studies have nominated genetic variation in the leucine-rich repeat and Ig containing 1 gene (LINGO1) as a risk for both Parkinson disease and essential tremor, providing the first genetic evidence of a link between the two conditions. Although undoubtedly genes remain to be identified, considerable progress has been achieved in the understanding of the genetic basis of Parkinson disease. This same effort is now required for essential tremor. The use of next-generation high-throughput sequencing and genotyping technologies will help pave the way for future insight leading to advances in diagnosis, prevention and cure.

  9. Accuracy of forecast of mine tremors location

    Energy Technology Data Exchange (ETDEWEB)

    Jan Drzewieck [Central Mining Institute, Katowice (Poland)

    2009-09-15

    The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life (in terms of distance) referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining intensity (longwall face speed) on the location of mine tremor sources, both in the direction of longwall life (in terms of distance) and towards the surface. The presented material has been prepared based on the results of tests and measurements carried out at the Central Mining Institute. 8 refs., 5 figs.

  10. Accuracy of forecast of mine tremors location

    Institute of Scientific and Technical Information of China (English)

    DRZEWIECKI Jan

    2009-01-01

    The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life (in terms of distance) referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining inten-sity (longwall face speed) on the location of mine tremor sources, both in the direction of longwall life (in terms of distance) and towards the surface. The presented material has been prepared basing on the results of tests and measurements carried out at the Central Mining Institute.

  11. Regional differences in species composition and toxigenic potential among Fusarium head blight isolates from Uruguay indicate a risk of nivalenol contamination in new wheat production areas.

    Science.gov (United States)

    Umpiérrez-Failache, M; Garmendia, G; Pereyra, S; Rodríguez-Haralambides, A; Ward, T J; Vero, S

    2013-08-16

    Members of the Fusarium graminearum species complex (FGSC) are the primary cause of Fusarium head blight (FHB) of wheat, and frequently contaminate grain with trichothecene mycotoxins that pose a serious threat to food safety and animal health. The species identity and trichothecene toxin potential of 151 FGSC isolates collected from wheat in Uruguay were determined via multilocus genotyping. Although F. graminearum with the 15ADON trichothecene type accounted for 86% of the isolates examined, five different FGSC species and all three trichothecene types were identified in this collection. This is the first report of Fusarium asiaticum, Fusarium brasilicum, Fusarium cortaderiae, and Fusarium austroamericanum from Uruguay. In addition, we observed significant (Pcomposition of FGSC species and trichothecene types within Uruguay. Isolates of F. graminearum with the 15ADON type were the most prevalent in western provinces (95%), while F. asiaticum (43%) and the NIV type (61%) predominated in the new wheat production zone in Cerro Largo along Uruguay's eastern border with Brazil. F. graminearum isolates (15ADON type) were significantly (Pwheat than were isolates from the other species examined (NIV or 3ADON types). However, F. graminearum isolates (15ADON type) were significantly (P<0.05) more sensitive to tebuconazole than isolates from other species (NIV type). These results document substantial heterogeneity among the pathogens responsible for FHB in Uruguay. In addition, the regional predominance of the NIV trichothecene type is of significant concern to food safety and indicates that additional monitoring of nivalenol levels in grain may be required.

  12. Discriminating Tectonic Tremor from Magmatic Processes in Observationally Challenging Environments

    Science.gov (United States)

    Brown, J. R.; Beroza, G. C.

    2011-12-01

    Deep tectonic tremor is a long-duration, low amplitude signal that has been shown to consist of low frequency earthquakes (LFEs) on the plate interface in subduction zones. Detecting LFEs from tremor-like signals in subduction settings can be challenging due to the combination of volcanic seismicity and sparse station geometry. This is particularly true for island arcs such as the Alaska-Aleutian subduction zone where the islands are small and noise levels are high. We have detected and located LFEs within tremor signals along the Alaska-Aleutian Arc in four locations: Kodiak Island, Alaska Peninsula, eastern Aleutians, and the Andreanof Islands. In all areas, the LFEs are located 10-40 km trenchward of the volcanic chain at depths ranging from 45-70 km. Location errors are significant (+/- 20 km in depth) due to sparse station geometry such that there is the possibility that the tremor could be associated with nearby volcanoes. Since most documented volcanic tremor is located in the shallow crust, it can often be discriminated from tectonic tremor simply based on location. However, deep volcanic tremor has been documented in Hawaii to depths of 40 km and could be more widespread. In the Aleutian arc, deep long period events (DLPs), which are thought to result from the movement of magma and volatiles, have been located as deep as 45 km and sometimes resemble tremor-like signals. The spectral character is another potential discriminant. We compare the cepstra (Fourier transform of the logarithmic power spectrum of a time series) of the tectonic tremor-like signals/LFEs and DLPs associated with volcanoes. Source characteristics of DLPs (non-shear slip) and tectonic tremor/LFEs (shear slip) are distinct and should be noticeable in the cepstral domain. This approach of using tremor locations and cepstral analysis could be useful for detecting and differentiating tectonic tremor from deep volcanic processes in other island arcs as well.

  13. Tremor as observed by the Array of Arrays in Cascadia

    Science.gov (United States)

    Ghosh, A.; Vidale, J. E.; Creager, K. C.

    2010-12-01

    We are capturing the intimate details of tremor activity in Cascadia with 8 small-aperture seismic arrays in northwestern Washington. The Array of Arrays (AoA) focuses on the tremor-active megathrust, including the area we previously imaged with a solo seismic array in 2008 [Ghosh et al., GRL, 2009, 2010]. Each array consists of 10 to 20 three-component sensors recording in continuous mode. Since it became operational in June 2009, the AoA has recorded several minor tremor episodes, and the recent episodic tremor and slip (ETS) event in August 2010. During the ETS event, each array was augmented by 10 additional single-channel, vertical-component sensors. We have already started to analyze seismic data for tremor episodes in July 2009, and March 2010. At each array, we apply a beamforming technique to stack the seismic energy at every 0.2 Hz from 2 to 15 Hz. During active tremor, the arrays show stable slowness, and azimuth over time, and up to 15 Hz energy on vertical channels, and 6 Hz on horizontals, with slowness consistent with the P and S waves respectively (Figure 1). Vidale et al. in this meeting provide a detailed description of a weeklong tremor episode in March 2010. The ETS started early second week of August about 60 km south of our arrays, and in a week or so, migrated along-strike to the north passing directly underneath the arrays. Strong tremor is still active about 50 km north of the arrays as we write this abstract. We will imminently analyze this data, and by the time of AGU, have preliminary results to present. Currently, we are developing an algorithm to focus as many arrays as possible to locate the tremor sources. With fine tremor detection capability and good azimuthal coverage, our AoA will better resolve the various confounding features of tremor spatiotemporal distribution (e.g., tremor patches, bands, streaks, rapid tremor reversals, low frequency earthquakes) that have been recently discovered in Cascadia. The AoA is poised to provide

  14. Towards closed-loop deep brain stimulation: decision tree-based essential tremor patient's state classifier and tremor reappearance predictor.

    Science.gov (United States)

    Shukla, Pitamber; Basu, Ishita; Tuninetti, Daniela

    2014-01-01

    Deep Brain Stimulation (DBS) is a surgical procedure to treat some progressive neurological movement disorders, such as Essential Tremor (ET), in an advanced stage. Current FDA-approved DBS systems operate open-loop, i.e., their parameters are unchanged over time. This work develops a Decision Tree (DT) based algorithm that, by using non-invasively measured surface EMG and accelerometer signals as inputs during DBS-OFF periods, classifies the ET patient's state and then predicts when tremor is about to reappear, at which point DBS is turned ON again for a fixed amount of time. The proposed algorithm achieves an overall accuracy of 93.3% and sensitivity of 97.4%, along with 2.9% false alarm rate. Also, the ratio between predicted tremor delay and the actual detected tremor delay is about 0.93, indicating that tremor prediction is very close to the instant where tremor actually reappeared.

  15. Episodic tremor and slip in Northern Sumatra subduction zone

    Science.gov (United States)

    Sianipar, Dimas; Subakti, Hendri

    2017-07-01

    The first reported observation of non-volcanic tremor in Sunda Arc in Sumbawa, Indonesia open a possibility of discovery of episodic tremor and slip (ETS) from out of Pacific Rim. Non-volcanic tremor gives some important information about dynamic of plate boundaries. The characteristics of these tremors are visually as non-impulsive, high frequency, long-duration and low-amplitude signals. Tectonic tremor occurred in a transition part of brittle-ductile of a fault and frequently associated with the shearing mechanism of slow slip. Tectonic tremor is a seismic case that also very interested, because it shows strong sensitivity to stress changes. Deep non-volcanic tremor is usually associated with episodic slow-slip events. Tectonic tremor is found in close association with geodetically observed slow-slip events (SSE) in subduction zones. One research found that there is possibility of SSE occurrence on Banyak Islands, North Sumatra revealed from coral observation. The SSE occurred on the Banyak Islands portion of the megathrust at 30-55 km depth, within the downdip transition zone. We do a systematic search of episodic tremor and its possible relationship with slow-slip phenomena in Northern Sumatra subduction zone. The spectrogram analysis is done to analyze the potential tremor signals. We use three component broadband seismic stations with 20, 25, and 50 sampling per second (BH* and SH* channels). We apply a butterworth 5 Hz highpass filter to separate the signal as local tremor and teleseismic/regional earthquakes. Before computing spectrogram to avoid high-frequency artifacts to remote triggering, we apply a 0.5 Hz filter. We also convert the binary seismic data into sound waves to make sure that these events meet the tectonic tremor criterion. We successfully examine 3 seismic stations with good recording i.e. GSI, SNSI and KCSI. We find there are many evidences of high frequency episodic tremor like signals. This include an analysis of potential triggered

  16. [A case of chronic inorganic mercury poisoning with progressive intentional tremor and remarkably prolonged latency of P300].

    Science.gov (United States)

    Shikata, E; Mochizuki, Y; Oishi, M; Takasu, T

    1998-12-01

    A 59-year-old man showed slowly progressive intentional tremor for 40 years prior to first visit to us in 1996. He was exposed to mercury vapor for about 3 years (1956-1959) and the diagnosis of chronic inorganic mercury poisoning was made. Hasegawa dementia scale-revised (HDS-R), mini-mental state (MMS) examination and P300 examination were performed. HDS-R and MMS were within normal range but the latency of P300 was remarkably prolonged. His tremor was considered to be due to chronic inorganic poisoning because there were no other causes and the frequency of his tremor was 3-4 Hz. which was lower than that in essential tremor. The prolonged P300 latency was also considered to be due to the same cause because there were no other causes and the head MRI were normal. Chronic inorganic mercury poisoning has been reported to produce organic changes in the brain and P300 is considered to be useful to detect these changes.

  17. [Antifugal susceptibility testing and antifugal traditional Chinese medicines screening of oral Candida isolated from head and neck cancer patients treated with radiotherapy or chemotherapy].

    Science.gov (United States)

    Zhao, Min; Zhou, Zeng-Tong; Zhang, Wei-Dong

    2006-04-01

    To evaluate the sensitivity and resistance of pathogenic oral Candida spp. isolated from head and neck cancer patients treated with radiotherapy or chemotherapy to antifungal agents. To screen antifugal agents from Chinese traditional and herbal drugs by NCCLS M27-A2 method. Using YBC Test Kit to identify 20 clinical oral Candida isolated from head and neck cancer patients treated with radiotherapy or chemotherapy. The in vitro susceptibilities of 20 oral Candida spp. to 5-flucytosine (5-FC), itraconazole (ITR), fluconazole (FLU), the extracts of 6 Chinese traditional and herbal drugs (caltrop, honeysuckle flower, dandelion, green tea, pine bark, red trefoil) and utility componets of 7 Chinese traditional and herbal drugs (sophorcarpidine, aloperine, archin, glycyrrhizic acid, glycosides of white peony root, glycosides of baikal skullcap root, hydrochloric berberine) were determined by NCCLS M27-A2 method. The proportion of no-C. albicans in all Candida spp. were 25%. All strains were sensitive to 5-flucytosine, 25% stains were resistant to fluconazole and 40% stains were resistant to itraconazole. In all agents from Chinese traditional and herbal drugs, glycosides of white peony root and hydrochloric berberine (C20H18CINO4) exhibited antifungal activity, especially to C. glabrates. The proportion of no-C. albicans in all oral Candida spp. isolated from head and neck cancer patients treated with radiotherapy or chemotherapy was pretty high. NCCLS M27-A2 micro-dilution method is a reliable and reproducible method and can be used to screen antifugal agents from Chinese traditional and herbal drugs.

  18. Characterizing the Relationship of Tremor and Slip during Recent ETS Events in Northern Cascadia using Strainmeters, GPS, and Tremor Observations

    Science.gov (United States)

    Krogstad, R. D.; Schmidt, D. A.

    2014-12-01

    We investigate the relationship between slip and tremor during multiple recent slow slip events in northern Cascadia. While the relationship of geodetically detectable slow slip and nonvolcanic tremor appears to be broadly coincident, the exact spatial and temporal characteristics remain unclear at a finer scale. Typical GPS derived slip distributions tend to be spatially and temporally smoothed and offset slightly updip of tremor distributions. These discrepancies may be real, or they may be a consequence of the resolution of GPS data or an artifact of the inversion methodology. Borehole strainmeters provide additional independent geodetic constraints for characterizing slip, provide greater temporal resolution, and greater precision than GPS. However, various non-tectonic artifacts and other sources of error have limited the number of usable stations and made deriving reliable information from strainmeters during slip events difficult. We utilize strainmeters with low levels of noise and minimal observable artifacts to constrain forward models and to provide additional independent observations in joint geodetic inversions with GPS data. A series of slip distributions are derived by inverting strainmeter and GPS data using the Kalman-filter-based Extended Network Inversion Filter. To compare the tremor distributions to the geodetically derived slip we also construct slip distributions using tremor occurrences as a proxy for localized slip on the plate interface. The magnitude of slip per tremor occurrence is then scaled to best match the observed surface displacements. Separate slip distributions informed by GPS and tremor are then used to predict strain time series. The comparisons between strain predictions and observations produce mixed results. This may indicate that that tremor and slip are not always coincident. This is particularly evident during the Aug. 2010 event, where the peak GPS-derived slip is located in a region with decreased tremor activity

  19. Minimising tremor in a joystick using fuzzy logic

    NARCIS (Netherlands)

    van der Zwaag, B.J.; Corbett, Dan; Jain, Lakhmi; Kappen, H.J.; Duin, R.P.W.; Krose, B.J.A.; Segeth, W.

    We have designed and built a fuzzy logic controller which minimises the effect of Multiple Sclerosis (MS) hand tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electronic wheelchair by removing tremors from the joystick signal. The system

  20. Phenomenology of tremor-like signals observed over hydrocarbon reservoirs

    NARCIS (Netherlands)

    Dangel, S.; Schaepman, M.E.; Stoll, E.P.; Carniel, R.; Barzandji, O.; Rode, E.D.; Singer, J.M.

    2003-01-01

    We have observed narrow-band, low-frequency (1.5-4 Hz, amplitude 0.01-10 mum/s) tremor signals on the surface over hydrocarbon reservoirs (oil, gas and water multiphase fluid systems in porous media) at currently 15 sites worldwide. These 'hydrocarbon tremors' possess remarkably similar spectral and

  1. Capturing hand tremors with a fuzzy logic wheelchair joystick controller

    NARCIS (Netherlands)

    van der Zwaag, B.J.; Corbett, Dan

    1999-01-01

    We have designed and built a fuzzy logic wheelchair controller which minimizes the effect of Multiple Sclerosis and tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electric wheelchair by removing tremors from the joystick signal. The system interc

  2. Capturing hand tremors with a fuzzy logic wheelchair joystick controller

    NARCIS (Netherlands)

    Zwaag, van der Berend-Jan; Corbett, Dan

    1999-01-01

    We have designed and built a fuzzy logic wheelchair controller which minimizes the effect of Multiple Sclerosis and tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electric wheelchair by removing tremors from the joystick signal. The system interc

  3. Minimising tremor in a joystick using fuzzy logic

    NARCIS (Netherlands)

    Zwaag, van der Berend-Jan; Corbett, Dan; Jain, Lakhmi

    1999-01-01

    We have designed and built a fuzzy logic controller which minimises the effect of Multiple Sclerosis (MS) hand tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electronic wheelchair by removing tremors from the joystick signal. The system intercept

  4. Phenomenology of tremor-like signals observed over hydrocarbon reservoirs

    NARCIS (Netherlands)

    Dangel, S.; Schaepman, M.E.; Stoll, E.P.; Carniel, R.; Barzandji, O.; Rode, E.D.; Singer, J.M.

    2003-01-01

    We have observed narrow-band, low-frequency (1.5-4 Hz, amplitude 0.01-10 mum/s) tremor signals on the surface over hydrocarbon reservoirs (oil, gas and water multiphase fluid systems in porous media) at currently 15 sites worldwide. These 'hydrocarbon tremors' possess remarkably similar spectral and

  5. Morphometric and functional MRI changes in essential tremor with and without resting tremor.

    Science.gov (United States)

    Nicoletti, Valentina; Cecchi, Paolo; Frosini, Daniela; Pesaresi, Ilaria; Fabbri, Serena; Diciotti, Stefano; Bonuccelli, Ubaldo; Cosottini, Mirco; Ceravolo, Roberto

    2015-03-01

    The etiopathogenesis of essential tremor (ET) is still debated, since the predominant role of circuit dysfunction or brain degenerative changes has not been clearly established. The relationship with Parkinson's Disease (PD) is also controversial and resting tremor occurs in up to 20 % of ET. We investigated the morphological and functional changes associated with ET and we assessed potential differences related to the presence (ET+R) or absence (ET-R) of resting tremor. 32 ET patients (18 ET+R; 14 ET-R) and 12 healthy controls (HC) underwent 3T-MRI protocol including Spoiled Gradient T1-weighted sequence for Voxel-Based Morphometry (VBM) analysis and functional MRI during continuous writing of "8" with right dominant hand. VBM analysis revealed no gray and white matter atrophy comparing ET patients to HC and ET+R to ET-R patients. HC showed a higher BOLD response with respect to ET patients in cerebellum and other brain areas pertaining to cerebello-thalamo-cortical circuit. Between-group activation maps showed higher activation in precentral gyrus bilaterally, right superior and inferior frontal gyri, left postcentral gyrus, superior and inferior parietal gyri, mid temporal and supramarginal gyri, cerebellum and internal globus pallidus in ET-R compared to ET+R patients. Our findings support that the dysfunction of cerebello-thalamo-cortical network is associated with ET in absence of any morphometric changes. The dysfunction of GPi in ET+R patients, consistently with data reported in PD resting tremor, might suggest a potential role of this structure in this type of tremor.

  6. Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor.

    Science.gov (United States)

    Heo, Jae-Hoon; Kim, Ji-Won; Kwon, Yuri; Lee, Sang-Ki; Eom, Gwang-Moon; Kwon, Do-Young; Lee, Chan-Nyeong; Park, Kun-Woo; Manto, Mario

    2015-01-01

    Essential tremor is an involuntary trembling of body limbs in people without tremor-related disease. In previous study, suppression of tremor by sensory electrical stimulation was confirmed on the index finger. This study investigates the effect of sensory stimulation on multiple segments and joints of the upper limb. It denotes the observation regarding the effect's continuity after halting the stimulation. 18 patients with essential tremor (8 men and 10 women) participated in this study. The task, "arms stretched forward", was performed and sensory electrical stimulation was applied on four muscles of the upper limb (Flexor Carpi Radialis, Extensor Carpi Radialis, Biceps Brachii, and Triceps Brachii) for 15 seconds. Three 3-D gyro sensors were used to measure the angular velocities of segments (finger, hand, and forearm) and joints (metacarpophalangeal and wrist joints) for three phases of pre-stimulation (Pre), during-stimulation (On), and 5 minute post-stimulation (P5). Three characteristic variables of root-mean-squared angular velocity, peak power, and peak power frequency were derived from the vector sum of the sensor signals. At On phase, RMS velocity was reduced from Pre in all segments and joints while peak power was reduced from Pre in all segments and joints except for forearm segment. Sensory stimulation showed no effect on peak power frequency. All variables at P5 were similar to those at On at all segments and joints. The decrease of peak power of the index finger was noted by 90% during stimulation from that of On phase, which was maintained even after 5 min. The results indicate that sensory stimulation may be an effective clinical method to treat the essential tremor.

  7. Deterministic properties of mine tremor aftershocks

    CSIR Research Space (South Africa)

    Kgarume, TE

    2010-10-01

    Full Text Available on Deep and High Stress Mining, 6-8 October 2010, Santiago CHILE Deterministic properties of mine tremor aftershocks T.E. Kgarume CSIR Centre for Mining Innovation and University of the Witwatersrand, South Africa S.M. Spottiswoode Consultant, South... : Dyke 7 7 : Span Figure 1 Simplified mine plan showing the main elements of stopes in South African gold mines 5th International Seminar on Deep and High Stress Mining, 6-8 October 2010, Santiago CHILE Table 1 Datasets used in the analysis...

  8. Modeling noisy time series Physiological tremor

    CERN Document Server

    Timmer, J

    1998-01-01

    Empirical time series often contain observational noise. We investigate the effect of this noise on the estimated parameters of models fitted to the data. For data of physiological tremor, i.e. a small amplitude oscillation of the outstretched hand of healthy subjects, we compare the results for a linear model that explicitly includes additional observational noise to one that ignores this noise. We discuss problems and possible solutions for nonlinear deterministic as well as nonlinear stochastic processes. Especially we discuss the state space model applicable for modeling noisy stochastic systems and Bock's algorithm capable for modeling noisy deterministic systems.

  9. Vocal Tremor: Novel Therapeutic Target for Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Vinod K. Ravikumar

    2016-10-01

    Full Text Available Tremulous voice is characteristically associated with essential tremor, and is referred to as essential vocal tremor (EVT. Current estimates suggest that up to 40% of individuals diagnosed with essential tremor also present with EVT, which is associated with an impaired quality of life. Traditional EVT treatments have demonstrated limited success in long-term management of symptoms. However, voice tremor has been noted to decrease in patients receiving deep brain stimulation (DBS with the targeting of thalamic nuclei. In this study, we describe our multidisciplinary procedure for awake, frameless DBS with optimal stimulation targets as well as acoustic analysis and laryngoscopic assessment to quantify tremor reduction. Finally, we investigate the most recent clinical evidence regarding the procedure.

  10. Tectonic tremor and LFEs on a reverse fault in Taiwan

    Science.gov (United States)

    Aguiar, Ana C.; Chao, Kevin; Beroza, Gregory C.

    2017-07-01

    We compare low-frequency earthquakes (LFEs) from triggered and ambient tremor under the southern Central Range, Taiwan. We apply the PageRank algorithm used by Aguiar and Beroza (2014) that exploits the repetitive nature of the LFEs to find repeating LFEs in both ambient and triggered tremor. We use these repeaters to create LFE templates and find that the templates created from both tremor types are very similar. To test their similarity, we use both interchangeably and find that most of both the ambient and triggered tremor match the LFE templates created from either data set, suggesting that LFEs for both events have a common origin. We locate the LFEs by using local earthquake P wave and S wave information and find that LFEs from triggered and ambient tremor locate to between 20 and 35 km on what we interpret as the deep extension of the Chaochou-Lishan Fault.

  11. Exploring dielectric elastomers as actuators for hand tremor suppression

    Science.gov (United States)

    Kelley, Christopher R.; Kauffman, Jeffrey L.

    2017-04-01

    Pathological tremor results in undesired motion of body parts, with the greatest effect typically occurring in the hands. Since common treatment methods are ineffective in some patients or have risks associated with surgery or side effects, researchers are investigating mechanical means of tremor suppression. This work explores the viability of dielectric elastomers as the actuators in a tremor suppression control system. Dielectric elastomers have many properties similar to human muscle, making them a natural fit for integration into the human biomechanical system. This investigation develops a model of the integrated wrist-actuator system to determine actuator parameters that produce the necessary control authority without significantly affecting voluntary motion. Furthermore, this paper develops a control law for the actuator voltage to increase the effective viscous damping of the system. Simulations show excellent theoretical tremor suppression, demonstrating the potential for dielectric elastomers to suppress tremor while maximizing compatibility between the actuator and the human body.

  12. High prevalence of reported tremor in Klinefelter syndrome.

    Science.gov (United States)

    Harlow, Tanya L; Gonzalez-Alegre, Pedro

    2009-06-01

    Several uncontrolled reports in the literature dating from decades ago suggest a link between Klinefelter syndrome (KS) and essential tremor (ET). Aiming to determine whether this association truly exists, we designed a controlled survey to ascertain the prevalence of reported tremor in KS. We identified subjects with KS through our hospital database and recruited controls among men who were accompanying patients to our Neurology Clinic. The presence of tremor and other variables were recorded employing a previously validated questionnaire. Whereas our control population was slightly older and more frequently reported a family history of tremor, the frequency of reported tremor was significantly higher in subjects with KS than controls with onset at a younger age. In addition, a high proportion of subjects with KS indicated gait imbalance. In summary, our study supports the previously reported association of an ET-like syndrome and KS.

  13. Source Processes Revealed at Two Guatemalan Volcanoes: Insights from Multidisciplinary Observations of Harmonic Tremor and Numerical Modeling

    Science.gov (United States)

    Brill, K. A.; Waite, G. P.

    2012-12-01

    Tremor signals at volcanoes are typically attributed to fluid movement within the system. Characteristics of harmonic tremor (i.e. duration, frequency content, polarization) can convey detailed information about source processes from which they emanate, but decoding these signals poses great challenges due to the complexity of volcanic environments. We recorded instances of harmonic tremor at both Santiaguito and Fuego volcanoes Guatemala, Central America. The instances of harmonic tremor occur both independent from and contemporaneous with explosions, and last anywhere from 30 seconds to tens of minutes. The signals have fundamental frequencies between 0.3 and 2.5 Hz, with as many as 20 overtones, and exhibit spectral gliding of up to 0.75 Hz over the course of an event, changing as quickly as 0.1 Hz/second. Field observations; video recordings; and time-lapse, ultraviolet, and thermal imagery; collected simultaneously with acoustic and seismic recordings allow us to constrain source locations and processes beyond what would otherwise be possible just acoustic and seismic recordings. We propose that the harmonic tremor signals are generated by nonlinear excitation of fracture walls as gas vents out of the systems. Additionally, we investigate the complex wavefield generated by harmonic tremor and the heterogeneous volcanic media. Particle motions at both volcanoes are typically elliptical, but vary dramatically over time as the fundamental frequency glides up and down (see figure). In addition, the particle motions of harmonics often have different polarities from each other and the fundamental frequency. Through finite difference modeling, we isolate the effects of near-field terms, topography, and source mechanism to explore each of these factors' contribution to the unexpected behavior.

  14. Non-volcanic tremor driven by large transient shear stresses.

    Science.gov (United States)

    Rubinstein, Justin L; Vidale, John E; Gomberg, Joan; Bodin, Paul; Creager, Kenneth C; Malone, Stephen D

    2007-08-01

    Non-impulsive seismic radiation or 'tremor' has long been observed at volcanoes and more recently around subduction zones. Although the number of observations of non-volcanic tremor is steadily increasing, the causative mechanism remains unclear. Some have attributed non-volcanic tremor to the movement of fluids, while its coincidence with geodetically observed slow-slip events at regular intervals has led others to consider slip on the plate interface as its cause. Low-frequency earthquakes in Japan, which are believed to make up at least part of non-volcanic tremor, have focal mechanisms and locations that are consistent with tremor being generated by shear slip on the subduction interface. In Cascadia, however, tremor locations appear to be more distributed in depth than in Japan, making them harder to reconcile with a plate interface shear-slip model. Here we identify bursts of tremor that radiated from the Cascadia subduction zone near Vancouver Island, Canada, during the strongest shaking from the moment magnitude M(w) = 7.8, 2002 Denali, Alaska, earthquake. Tremor occurs when the Love wave displacements are to the southwest (the direction of plate convergence of the overriding plate), implying that the Love waves trigger the tremor. We show that these displacements correspond to shear stresses of approximately 40 kPa on the plate interface, which suggests that the effective stress on the plate interface is very low. These observations indicate that tremor and possibly slow slip can be instantaneously induced by shear stress increases on the subduction interface-effectively a frictional failure response to the driving stress.

  15. Neuroimaging essentials in essential tremor: a systematic review.

    Science.gov (United States)

    Sharifi, Sarvi; Nederveen, Aart J; Booij, Jan; van Rootselaar, Anne-Fleur

    2014-01-01

    Essential tremor is regarded to be a disease of the central nervous system. Neuroimaging is a rapidly growing field with potential benefits to both diagnostics and research. The exact role of imaging techniques with respect to essential tremor in research and clinical practice is not clear. A systematic review of the different imaging techniques in essential tremor is lacking in the literature. We performed a systematic literature search combining the terms essential tremor and familial tremor with the following keywords: imaging, mri, vbm, dwi, fmri, pet and spect, both in abbreviated form as well as in full form. We summarize and discuss the quality and the external validity of each study and place the results in the context of existing knowledge regarding the pathophysiology of essential tremor. A total of 48 neuroimaging studies met our search criteria, roughly divided into 19 structural and 29 functional and metabolic studies. The quality of the studies varied, especially concerning inclusion criteria. Functional imaging studies indicated cerebellar hyperactivity during rest and during tremor. The studies also pointed to the involvement of the thalamus, the inferior olive and the red nucleus. Structural studies showed less consistent results. Neuroimaging techniques in essential tremor give insight into the pathophysiology of essential tremor indicating the involvement of the cerebellum as the most consistent finding. GABAergic dysfunction might be a major premise in the pathophysiological hypotheses. Inconsistencies between studies can be partly explained by the inclusion of heterogeneous patient groups. Improvement of scientific research requires more stringent inclusion criteria and application of advanced analysis techniques. Also, the use of multimodal neuroimaging techniques is a promising development in movement disorders research. Currently, the role of imaging techniques in essential tremor in daily clinical practice is limited.

  16. Cosmic signatures in earth's seismic tremor?

    CERN Document Server

    Mulargia, Francesco

    2016-01-01

    Even in absence of earthquakes, each site on earth experiences continuous elastic vibrations which are mostly traced to the non-linear interactions of sea waves. However, the fine structure of the spectrum at mHz frequencies shows hundreds of highly significant narrow bandwidth peaks, with a persistence and a coincidence with solar acoustic eigenmodes which are incompatible with any geophysical origin. The feasibility of a common cosmic origin is evaluated through an estimate of the gravitational wave cross-section of the earth, combined with its elastic response and with the stochastic amplification produced by the interference of the cosmic signal with tremor of oceanic origin. The measured spectral peaks appear compatible with a gravitational monochromatic illumination at strains $h \\gtrsim 10^{-20} $. We analize in detail the band around 2.614 mHz, where the binary white dwarf J0651+2844 - which is the second strongest known gravitational stellar source - is expected to emit. Compatible spectral tremor pe...

  17. Optimization and head-to-head comparison of MISSR-PCR, ERIC-PCR, RAPD and 16S rRNA evolutionary clock for the genotyping of Vibrio cholerae isolated in China.

    Science.gov (United States)

    Mo, Q H; Wang, H B; Tan, H; An, S L; Feng, Z L; Wang, Q; Lin, J C; Yang, Z

    2015-01-01

    To establish a new genotyping method for Vibrio cholerae and compare it with other methods. In the current study, a modified inter simple sequence repeat-polymerase chain reaction (MISSR-PCR) system was developed via several rounds of optimisation. Comparison study was then conducted between MISSR-PCR and three other methods, including enterobacterial repetitive intergenic consensus sequences-based PCR (ERIC-PCR), randomly amplified polymorphic DNA (RAPD) and 16S rRNA evolutionary clock, for the detection and genetic tracing of Vibrio cholerae isolated from seafood in China. The results indicated that the MISSR-PCR system could generate the highest polymorphic fingerprinting map in a single round PCR and showed the best discriminatory ability for Vibrio cholerae genotyping by clearly separating toxigenic/nontoxigenic strains, local/foreign strains, and O1/O139/non-O1/non-O139 serogroup strains, comparing to ERIC-PCR, RAPD and 16S rRNA evolutionary clock. Moreover, the MISSR-PCR is superior to previously described traditional simple sequence repeat based PCR method on genotyping by more clearly separating different clusters. To the best of our knowledge, this is the first head-to-head comparison of four detection and genotyping methods for Vibrio cholerae The MISSR-PCR system established here could serve as a simple, quick, reliable and cost-effective tool for the genotyping and epidemiological study.

  18. Optimization and head-to-head comparison of MISSR-PCR, ERIC-PCR, RAPD and 16S rRNA evolutionary clock for the genotyping of Vibrio cholerae isolated in China

    Directory of Open Access Journals (Sweden)

    Q H Mo

    2015-01-01

    Full Text Available Purpose: To establish a new genotyping method for Vibrio cholerae and compare it with other methods. Materials and Methods: In the current study, a modified inter simple sequence repeat-polymerase chain reaction (MISSR-PCR system was developed via several rounds of optimisation. Comparison study was then conducted between MISSR-PCR and three other methods, including enterobacterial repetitive intergenic consensus sequences-based PCR (ERIC-PCR, randomly amplified polymorphic DNA (RAPD and 16S rRNA evolutionary clock, for the detection and genetic tracing of Vibrio cholerae isolated from seafood in China. Result: The results indicated that the MISSR-PCR system could generate the highest polymorphic fingerprinting map in a single round PCR and showed the best discriminatory ability for Vibrio cholerae genotyping by clearly separating toxigenic/nontoxigenic strains, local/foreign strains, and O1/O139/non-O1/non-O139 serogroup strains, comparing to ERIC-PCR, RAPD and 16S rRNA evolutionary clock. Moreover, the MISSR-PCR is superior to previously described traditional simple sequence repeat based PCR method on genotyping by more clearly separating different clusters. Conclusion: To the best of our knowledge, this is the first head-to-head comparison of four detection and genotyping methods for Vibrio cholerae The MISSR-PCR system established here could serve as a simple, quick, reliable and cost-effective tool for the genotyping and epidemiological study.

  19. Rest and action tremor in Parkinson's disease: effects of Deep Brain Stimulation

    NARCIS (Netherlands)

    Heida, Tjitske; Wentink, E.C.

    2010-01-01

    One of the cardinal symptoms of Parkinson’s disease is rest tremor. While rest tremor generally disappears during sleep and voluntary movement, action tremor may be triggered by voluntary movement, and may even be more disabling than rest tremor. Deep brain stimulation (DBS) in the subthalamic

  20. Rest and action tremor in Parkinson's disease: effects of Deep Brain Stimulation

    NARCIS (Netherlands)

    Heida, T.; Wentink, E.C.

    2010-01-01

    One of the cardinal symptoms of Parkinson’s disease is rest tremor. While rest tremor generally disappears during sleep and voluntary movement, action tremor may be triggered by voluntary movement, and may even be more disabling than rest tremor. Deep brain stimulation (DBS) in the subthalamic nucle

  1. The distributed somatotopy of tremor: a window into the motor system

    NARCIS (Netherlands)

    Helmich, R.C.G.

    2013-01-01

    The posterior ventrolateral thalamus (VLp) plays a crucial role in Parkinson's tremor and in essential tremor: deep brain stimulation (DBS) of the VLp effectively diminishes both tremor types. Previous research has shown tremor oscillations in the VLp, but the spatial extent and somatotopy of these

  2. Real-Time Estimation of Pathological Tremor Parameters from Gyroscope Data

    Directory of Open Access Journals (Sweden)

    José L. Pons

    2010-03-01

    Full Text Available This paper presents a two stage algorithm for real-time estimation of instantaneous tremor parameters from gyroscope recordings. Gyroscopes possess the advantage of providing directly joint rotational speed, overcoming the limitations of traditional tremor recording based on accelerometers. The proposed algorithm first extracts tremor patterns from raw angular data, and afterwards estimates its instantaneous amplitude and frequency. Real-time separation of voluntary and tremorous motion relies on their different frequency contents, whereas tremor modelling is based on an adaptive LMS algorithm and a Kalman filter. Tremor parameters will be employed to drive a neuroprosthesis for tremor suppression based on biomechanical loading.

  3. Widespread Triggered Tremor In Japan Following the 2012 Mw8.6 Sumatra Earthquake

    Science.gov (United States)

    Chao, K.; Obara, K.

    2012-12-01

    Deep "non-volcanic" tremor has been observed at many major plate-boundary faults around the Pacific Rim. Recent studies have shown that the tremor triggered by the surface waves of teleseismic earthquake occurs on the same fault patches as the ambient tremor (i.e., those occurring spontaneously). The observations suggest that the triggered tremor can be used as a proxy to estimate the background tremor activity. Triggered and ambient tremors have been well studied along the Nankai subduction zone in southwest Japan. Recently, new identified triggered tremor sources were found in Hokkaido in northernmost Japan (Obara, 2012, submitted manuscript), suggesting, contrary to previous beliefs, that tremor can be observed in various tectonic environments. Here, we systematically search for triggered tremor on the main islands of Japan (i.e., Kyushu, Shikoku, Honshu, and Hokkaido) following the 2012/04/11 Mw 8.6 Sumatra earthquake. We examined a total of about 1300 seismic stations from the Hi-net operated by NIED (National Research Institute for Earth Science and Disaster Prevention) and other arrays operated by universities and other organizations. We first identified triggered tremor as a high-frequency, non-impulsive signal in phase with the large-amplitude teleseismic waves and then located the triggered tremor sources using a standard envelope cross-correlation technique. We also compared the tremor triggering potential with Love and Rayleigh waves by shifting the seismograms of tremor and surface waves back to the best tremor source. We observed clear triggered tremor following the 2012 Sumatra mainshock in Shikoku, Kii, and Tokai, where ambient tremors are very active and triggered tremors have been identified previously. Moreover, we successfully detected new triggered tremor sources in Hokkaido, Kyushu, and Kanto. In central Hokkaido, tremor triggered by the 2012 Sumatra earthquake was located at the same place where tremor was triggered by the 2004 Sumatra

  4. Suppression of enhanced physiological tremor via stochastic noise: initial observations.

    Directory of Open Access Journals (Sweden)

    Carlos Trenado

    Full Text Available Enhanced physiological tremor is a disabling condition that arises because of unstable interactions between central tremor generators and the biomechanics of the spinal stretch reflex. Previous work has shown that peripheral input may push the tremor-related spinal and cortical systems closer to anti-phase firing, potentially leading to a reduction in tremor through phase cancellation. The aim of the present study was to investigate whether peripherally applied mechanical stochastic noise can attenuate enhanced physiological tremor and improve motor performance. Eight subjects with enhanced physiological tremor performed a visuomotor task requiring the right index finger to compensate a static force generated by a manipulandum to which Gaussian noise (3-35 Hz was applied. The finger position was displayed on-line on a monitor as a small white dot which the subjects had to maintain in the center of a larger green circle. Electromyogram (EMG from the active hand muscles and finger position were recorded. Performance was measured by the mean absolute deviation of the white dot from the zero position. Tremor was identified by the acceleration in the frequency range 7-12 Hz. Two different conditions were compared: with and without superimposed noise at optimal amplitude (determined at the beginning of the experiment. The application of optimum noise reduced tremor (accelerometric amplitude and EMG activity and improved the motor performance (reduced mean absolute deviation from zero. These data provide the first evidence of a significant reduction of enhanced physiological tremor in the human sensorimotor system due to application of external stochastic noise.

  5. Suppression of enhanced physiological tremor via stochastic noise: initial observations.

    Science.gov (United States)

    Trenado, Carlos; Amtage, Florian; Huethe, Frank; Schulte-Mönting, Jürgen; Mendez-Balbuena, Ignacio; Baker, Stuart N; Baker, Mark; Hepp-Reymond, Marie-Claude; Manjarrez, Elias; Kristeva, Rumyana

    2014-01-01

    Enhanced physiological tremor is a disabling condition that arises because of unstable interactions between central tremor generators and the biomechanics of the spinal stretch reflex. Previous work has shown that peripheral input may push the tremor-related spinal and cortical systems closer to anti-phase firing, potentially leading to a reduction in tremor through phase cancellation. The aim of the present study was to investigate whether peripherally applied mechanical stochastic noise can attenuate enhanced physiological tremor and improve motor performance. Eight subjects with enhanced physiological tremor performed a visuomotor task requiring the right index finger to compensate a static force generated by a manipulandum to which Gaussian noise (3-35 Hz) was applied. The finger position was displayed on-line on a monitor as a small white dot which the subjects had to maintain in the center of a larger green circle. Electromyogram (EMG) from the active hand muscles and finger position were recorded. Performance was measured by the mean absolute deviation of the white dot from the zero position. Tremor was identified by the acceleration in the frequency range 7-12 Hz. Two different conditions were compared: with and without superimposed noise at optimal amplitude (determined at the beginning of the experiment). The application of optimum noise reduced tremor (accelerometric amplitude and EMG activity) and improved the motor performance (reduced mean absolute deviation from zero). These data provide the first evidence of a significant reduction of enhanced physiological tremor in the human sensorimotor system due to application of external stochastic noise.

  6. Familial orthostatic tremor and essential tremor in two young brothers: A rare entity

    Directory of Open Access Journals (Sweden)

    Kalyan B Bhattacharyya

    2013-01-01

    Full Text Available Orthostatic tremor (OT, is usually a disease of old age and is characterized by quivering movements of the legs during quiet standing or in the state of isometric contraction in the lower limbs. This is relieved on walking or on lying down. It is diagnosed by surface electromyography, particularly over the quadriceps femoris muscles which shows a distinctive frequency of 13 to 18 Hz on standing. Some investigators consider it as a variant of essential tremor (ET and the two conditions often co-exist. The disease is usually non-familial. Two brothers presented with tremor in the lower limbs on standing and on the outstretched hands without any family history. Subsequently, they were proved to be suffering from OT and ET by clinical examination and surface EMG. Simultaneous occurrence of OT and ET in two young brothers without any family history in the previous generation has not been described before and they also appeared at a much earlier age than what is described in the literature.

  7. Deep Brain Stimulation for Essential Vocal Tremor: A Technical Report.

    Science.gov (United States)

    Ho, Allen L; Choudhri, Omar; Sung, C Kwang; DiRenzo, Elizabeth E; Halpern, Casey H

    2015-03-01

    Essential vocal tremor (EVT) is the presence of a tremulous voice that is commonly associated with essential tremor. Patients with EVT often report a necessary increase in vocal effort that significantly worsens with stress and anxiety and can significantly impact quality of life despite optimal medical and behavioral treatment options. Deep brain stimulation (DBS) has been proposed as an effective therapy for vocal tremor, but very few studies exist in the literature that comprehensively evaluate the efficacy of DBS for specifically addressing EVT. We present a technical report on our multidisciplinary, comprehensive operative methodology for treatment of EVT with frameless, awake deep brain stimulation (DBS).

  8. Prominent Bilateral Hand Tremor in Hashimoto's Encephalopathy: A Video Demonstration.

    Science.gov (United States)

    Ramcharan, Kanterpersad; Hosein, Nadeem; Teelucksingh, Joel David; Rampersad, Fidel; Teelucksingh, Surujpal

    2016-01-01

    Hashimoto's encephalopathy often presents with neuropsychiatric manifestations including seizures and movement disorders. We describe a patient who presented with bilateral hand tremor and mild cognitive defects that fulfilled the criteria for a diagnosis of Hashimoto's encephalopathy. There was a rapid response to glucocorticoid therapy with relapse following treatment withdrawal. Recently published clinical criteria for the diagnosis of Hashimoto's encephalopathy include seizures, myoclonus, hallucinations, or stroke-like episodes but do not include tremor. Our case had mild cognitive dysfunction and a coarse tremor as the predominant clinical features, which probably represent mild disease.

  9. Evaluation of a screening instrument for essential tremor

    DEFF Research Database (Denmark)

    Lorenz, Delia; Papengut, Frank; Frederiksen, Henrik

    2008-01-01

    To evaluate a screening instrument for essential tremor (ET) consisting of a seven-item questionnaire and a spiral drawing. A total of 2,448 Danish twins aged 70 years or more and a second sample aged 60 years or more (n = 1,684) from a population-based northern German cross-sectional study (Pop....... Definite or probable ET was diagnosed in 104 patients, possible in 86 and other tremors in 98 patients. The sensitivity of the screening instrument was 70.5%, the positive predictive value was 64.9%, the specificity was 68.2%, and the negative predictive value was 73.5%. Tremor severity correlated...

  10. Searching for Tectonic Tremor on the North Anatolian Fault

    Science.gov (United States)

    Pfohl, A.; Warren, L. M.; Sit, S. M.; Brudzinski, M. R.

    2012-12-01

    Tectonic tremor, a relatively newly-discovered seismologic phenomenon, has been helpful in increasing our understanding of fault evolution and slip. Tectonic tremor was first identified in subduction zones, such as Cascadia and Japan. More recently, tremor was discovered on a transform boundary, the San Andreas Fault (SAF) in California. The North Anatolian Fault (NAF) in Turkey is also a transform boundary and has a similar slip rate to the SAF but is younger. Because tremor has not previously been identified on the NAF, our search was designed to identify signals with characteristics similar to those of tremor found in previous studies. In our search for tremor, we analyzed data from the North Anatolian Fault Passive Seismic Experiment that was deployed along the NAF in central Turkey from 2005 to 2008. This experiment included 39 broadband stations, some of which were located within a few kilometers of the NAF or its major splays. In other regions, tremor has been triggered by the surface waves of large earthquakes so we first checked if this was also the case for the NAF. For the 22 earthquakes of M ≥ 5.5 in or around Turkey during the time period of the experiment, we filtered the seismograms between 2-8 Hz, the dominant tremor passband for other regions. We inspected the filtered records but did not see any tremor triggered by surface waves. We then focused on identifying ambient tremor along the NAF using a frequency ratio scanning method. Since different types of seismic signals have peak amplitudes in different frequency bands, time periods with increased tremor activity may be identified by an increase in amplitude in the appropriate frequency band. In this step of the analysis, data from all stations were filtered from 2-5 Hz, 10-15, and 0.02-0.1 Hz to differentiate tremor, local earthquakes, and surface waves, respectively, and the amplitude was computed for 5-minute-long windows for each passband. We more closely investigated time periods with

  11. The Commercial TREMOR Strong-Motion Seismograph

    Science.gov (United States)

    Evans, J. R.; Hamstra, R. H.; Kuendig, C.; Camina, P.

    2001-12-01

    -connected cell-phone-based Internet technology (CDPD), but any RS-232 connected telemetry system is a viable candidate (spread spectrum, CDMA, GSM, POT). The instruments can be synchronized via CDPD to a few tenths of a second, or to full precision with an optional GPS receiver. Sensor RMS noise is 33 \\mathrm \\mu g over the band 0.1 to 35 Hz, 11 \\mathrm \\mu g$ over the band 0.1 to 1.0 Hz; the sensor is extremely linear (far better than 1% of full scale); temperature compensation is to better than 1% of full scale. TREMOR-class instruments are intended to fill the niche of high spatial resolution with an economical low-maintenance device, while conventional instruments continue to pursue maximum amplitude resolution. The TREMOR instrument also has applications in areas where budget or access limitations require lower purchase, installation, or maintenance cost (commercial ANSS partners, remote sites, on-call aftershock arrays, extremely dense arrays, and organizations with limited budgets). However, we primarily envision large, mixed arrays of conventional and TREMOR instruments in urban areas, the former providing better early information from small events and the TREMOR instruments guaranteeing better spatial resolution and more near-field recording of large events. Together, they would meet the ANSS goal of dense near-real-time urban monitoring and the collection of requisite data for risk mitigation.

  12. Genetic diversity of Fusarium graminearum sensu lato isolates from wheat associated with Fusarium Head Blight in diverse geographic locations of Argentina.

    Science.gov (United States)

    Consolo, Verónica F; Ortega, Leonel M; Salerno, Graciela; Astoreca, Andrea L; Alconada, Teresa M

    2015-01-01

    Fusarium Head Blight is an important wheat disease in the Argentine Pampas region, being Fusarium graminearum the predominant pathogen. DNA polymorphism of the isolates was analyzed by IGS-RFLP and ISSR. IGS-RFLP and ISSR profiling were carried out using six endonucleases and eight primers, respectively. IGS-RFLP yielded 41 bands, 30 of which were polymorphic while ISSR produced 87 bands with 47 polymorphic bands. Both markers showed genetic variability among the analyzed isolates; however, IGS-RFLP was more efficient than ISSR, showing a higher polymorphic average (59.91%) than the latter (44.11%). The averages of polymorphic information content (PIC) were 0.211 and 0.129, respectively. Twenty haplotypes were identified by IGS-RFLP and 15 haplotypes by ISSR. Genotype clustering within dendrograms was different for both types of markers. The genetic groups obtained by IGS-RFLP showed a partial association to geographic origin. This is the first report on genetic variability of F. graminearum isolates from wheat in Argentina using IGS-RFLP and ISSR markers.

  13. Clinical characteristics of essential tremor%特发性震颤的临床特点

    Institute of Scientific and Technical Information of China (English)

    柳四新; 唐北沙; 严新翔; 杨期明; 杨晓苏; 金丽娟; 刘罗坤

    2001-01-01

    目的 探讨特发性震颤(ET)的临床特点。方法 对80例ET患者的临床资料进行分析。结果80例ET中男50例,女30例,发病年龄3~70岁,平均34.6±16.3岁,病程6个月~60年,平均14.2±9.9年。45例(56.3%)患者有阳性家族史,多呈常染色体显性遗传。临床主要表现为单症状的姿势性震颤,累及部位依次为手(92.5%)、咽喉部(21.3%)、头(20%)、下颏(17.5%)等。17.5%患者因震颤致日常生活困难。34例饮酒患者中,91.2%显示对酒精有反应性。6.3%患者并发帕金森病(PD)。61%患者小剂量心得安治疗有效。结论 本组ET患者男多于女,发病年龄轻,呈单峰模式,临床表现为单症状姿势性震颤,部分病例可伴发PD,小剂量心得安治疗大多有效。%Objective To investigate the clinical characteristics of essential tremor (ET).Methods The clinical materials of 80 patients with ET was analysed.Results In 80 patients with ET, 50 cases for the male, 30 cases for the female,the age at tremor onset was from 3 to 70 years old,the mean age was 34.6±16.3 years old,the course of disease was 6 months to 60 years,the mean 14.2±9.9 years. 45 patients (56.3%) had postive family history,they showed mostly autosomal dominant inheritance.The postural tremor was the main manifestation of essential tremor,tremor affected hand in 92.5% patients,throat in 21.3%,head in 20%,chin in 17.5%. Functional disability and impairment in 17.5% patients because of tremor.91.2% patients had the effect of alcohol occurred in 34 cases who had performed alcohol test.6.3% patients accompanied parkinson’s disease.A small dose of propranolol was effective in 61% patients.Conclusion In the ET group,the patients were mostly young,single model,the number of the male ET cases was more than the female,sole postural tremor,part of patients might accompany PD,a small dose of propranolol was effective.

  14. Effects of Isolate and Social Toys on the Social Interactions of Preschoolers in an Inclusive Head Start Classroom

    Science.gov (United States)

    Elmore, Shannon Renee; Vail, Cynthia O.

    2011-01-01

    The purpose of this study was to evaluate the effects of manipulating toy sets on the social verbal interaction that occurs between preschool-age children with disabilities and their typically developing peers. A single-subject alternating-treatments design was used to evaluate the effects of manipulating social toy sets and isolate toy sets on…

  15. Essential Tremor (ET): Coping Tips for Everyday Living

    Science.gov (United States)

    ... several marathons each year, raising funds and awareness. ET is a life-altering condition that makes everyday ... tremor. In order to assist people who have ET in continuing to live full, meaningful lives, the ...

  16. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS)

    Science.gov (United States)

    ... a patient may be under the care of multiple or varying specialists. These include but are not limited to: Neurologists (for tremor, ataxia, memory loss) Psychiatrists (for personality change, depression, mood disorders) Psychologists (for cognitive impairment) Movement disorders specialists (for ...

  17. Tremor in workers with low exposure to metallic mercury

    Energy Technology Data Exchange (ETDEWEB)

    Verberk, M.M.; Salle, H.J.A.; Kemper, C.H.

    1986-09-01

    In a fluorescent lamp production factory, a newly developed lightweight balance-tremormeter was used to measure postural tremor of the finger in 21 workers (ages 28 to 61) exposed for 0.5-19 yr to metallic mercury. In addition, tremor was measured in an indirect way by means of a hole-tremormeter. The excretion of mercury in urine was 9-53 (average 20) ..mu..mol/mol creatinine. With increasing mercury excretion, the following parameters increased: the acceleration of the tremor, the contribution of the neuromuscular component (8-12 Hz) to the power spectrum of the acceleration, the width of the power-spectrum and the score on the hole-tremormeter. The study indicates that exposure to metallic mercury below the current TLV (50 ..mu..g/m/sup 3/) may increase the tremor of the finger.

  18. Palatal tremor after lithium and carbamazepine use: a case report

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    Kuruvilla Anju

    2010-06-01

    Full Text Available Abstract Introduction Palatal tremor, characterized by rhythmic contractions of the soft palate, can occur secondary to pathology in the dentato-rubro-olivary pathway, or in the absence of such structural lesions. Its pathogenesis is only partially understood. We describe a case of probable drug-induced palatal tremor. Case presentation A 27-year-old Indian man had taken carbamazepine and lithium for 7 years for the treatment of a manic episode. He presented with a one-year history of bilateral rhythmic oscillations of his soft palate and tremors of his tongue. There were no other abnormalities detected from his examination or after detailed investigation. Conclusion Palatal tremors may result from medication used in the treatment of psychiatric disorders.

  19. Chin tremor in full-term neonate after hypoxia

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    Mônica Ayres de Araújo Scattolin

    Full Text Available CONTEXT: Newborns may present a range of motor phenomena that are not epileptic in nature. Chin tremor is an unusual movement disorder that typically starts in early childhood and may be precipitated by stress and emotion. Its pathophysiology has not been fully elucidated. CASE REPORT: We describe a full-term newborn that, immediately after neonatal anoxia, presented body and chin tremors that were unresponsive to anti-epileptic drugs. Subsequent neurological evaluation revealed signs of pyramidal tract damage and chin tremor triggered by percussion and crying. We discuss the hypothesis that the anatomopathological abnormality may lie at the level of the higher cortical centers or midbrain. CONCLUSIONS: Further studies are needed in order to gain greater comprehension of neonatal tremors. Recognition of the various etiological possibilities and consequent management of treatable causes is essential for care optimization.

  20. Voluntary driven elbow orthosis with speed controlled tremor suppression

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    Gil eHerrnstadt

    2016-03-01

    Full Text Available Robotic technology is gradually becoming commonplace in the medical sector and in the service of patients. Medical conditions that have benefited from significant technological development include stroke, for which rehabilitation with robotic devices is administered, and surgery assisted by robots. Robotic devices have also been proposed for assistance of movement disorders. Pathological tremor, among the most common movement disorders, is such one example. In practice, the dissemination and availability of tremor suppression robotic systems has been limited. Devices in the marketplace tend to either be non-ambulatory or to target specific functions such as eating and drinking.We have developed a one degree-of-freedom (DOF elbow orthosis that could be worn by an individual with tremor. A speed controlled voluntary driven suppression approach is implemented with the orthosis. Typically tremor suppression methods estimate the tremor component of the signal and produce a canceling counterpart signal. The suggested approach, instead estimates the voluntary component of the motion. A controller then actuates the orthosis based on the voluntary signal while simultaneously rejecting the tremorous motion.In this work, we tested the suppressive orthosis using a 1 DOF robotic system that simulates the human arm. The suggested suppression approach does not require a model of the human arm. Moreover, the human input along with the orthosis forearm gravitational forces, of nonlinear nature, are considered as part of the disturbance to the suppression system. Therefore, the suppression system can be modeled linearly. Nevertheless, the orthosis forearm gravitational forces can be compensated by the suppression system.The electromechanical design of the orthosis is presented, and data from an Essential Tremor patient is used as the human input. Velocity tracking results demonstrate an RMS error of 0.31 rad/s, and a power spectral density shows a reduction of

  1. Surface-wave potential for triggering tectonic (nonvolcanic) tremor

    Science.gov (United States)

    Hill, D.P.

    2010-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  2. Seismic Tremors and Magma Wagging During Explosive Volcanism

    Science.gov (United States)

    Jellinek, M.; Bercovici, D.

    2010-12-01

    Volcanic tremor is a ubiquitous feature of explosive eruptions. This ground oscillation persists for minutes to weeks and is characterized by a remarkably narrow band of frequencies (i.e., ~0.5 - 7 Hz). Prior to major eruptions, tremor can occur in concert with ground deformation probably related to a buildup of magmatic gas. Volcanic tremor is, thus, of particular value for eruption forecasting. Most models for volcanic tremor rely on specific properties of the geometry, structure and constitution of volcanic conduits as well as the gas content of the erupting magma. Because neither the initial structure nor the evolution of the magma-conduit system will be the same from one volcano to the next, it is surprising that tremor characteristics are so consistent among different volcanoes. Indeed, this universality of tremor properties remains a major enigma. Here we employ the contemporary view that silicic magma rises in the conduit as a columnar plug surrounded by a highly vesicular annulus of sheared bubbles. We demonstrate that, for most geologically relevant conditions, the magma column will oscillate or "wag" against the restoring "gas-spring" force of the annulus at observed tremor frequencies. In contrast to previous models, the magma wagging oscillation is relatively insensitive to the conduit structure and geometry, thereby predicting the narrow band of tremor frequencies observed around the world. Moreover, the model predicts that as an eruption proceeds there will be an upward drift in both the maximum frequency and the total signal frequency bandwidth, the nature of which depends on the explosivity of the eruption, as observed.

  3. Maximal force and tremor changes across the menstrual cycle.

    Science.gov (United States)

    Tenan, Matthew S; Hackney, Anthony C; Griffin, Lisa

    2016-01-01

    Sex hormones have profound effects on the nervous system in vitro and in vivo. The present study examines the effect of the menstrual cycle on maximal isometric force (MVC) and tremor during an endurance task. Nine eumenorrheic females participated in five study visits across their menstrual cycle. In each menstrual phase, an MVC and an endurance task to failure were performed. Tremor across the endurance task was quantified as the coefficient of variation in force and was assessed in absolute time and relative percent time to task failure. MVC decreases 23% from ovulation to the mid luteal phase of the menstrual cycle. In absolute time, the mid luteal phase has the highest initial tremor, though the early follicular phase has substantially higher tremor than other phases after 150 s of task performance. In relative time, the mid luteal phase has the highest level of tremor throughout the endurance task. Both MVC and tremor during an endurance task are modified by the menstrual cycle. Performance of tasks and sports which require high force and steadiness to exhaustion may be decreased in the mid luteal phase compared to other menstrual phases.

  4. Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits?

    Science.gov (United States)

    Helmich, Rick C; Hallett, Mark; Deuschl, Günther; Toni, Ivan; Bloem, Bastiaan R

    2012-11-01

    Tremor in Parkinson's disease has several mysterious features. Clinically, tremor is seen in only three out of four patients with Parkinson's disease, and tremor-dominant patients generally follow a more benign disease course than non-tremor patients. Pathophysiologically, tremor is linked to altered activity in not one, but two distinct circuits: the basal ganglia, which are primarily affected by dopamine depletion in Parkinson's disease, and the cerebello-thalamo-cortical circuit, which is also involved in many other tremors. The purpose of this review is to integrate these clinical and pathophysiological features of tremor in Parkinson's disease. We first describe clinical and pathological differences between tremor-dominant and non-tremor Parkinson's disease subtypes, and then summarize recent studies on the pathophysiology of tremor. We also discuss a newly proposed 'dimmer-switch model' that explains tremor as resulting from the combined actions of two circuits: the basal ganglia that trigger tremor episodes and the cerebello-thalamo-cortical circuit that produces the tremor. Finally, we address several important open questions: why resting tremor stops during voluntary movements, why it has a variable response to dopaminergic treatment, why it indicates a benign Parkinson's disease subtype and why its expression decreases with disease progression.

  5. Radiotherapy effect on frequency of Candida spp. and on virulence of C. albicans isolated from the oral cavity of head and neck cancer patients

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    DANIELA DAMBROSO

    2009-12-01

    Full Text Available The aim of this study was to investigate the diversity and prevalence of yeasts, and the virulence of C. albicans found in the oral cavity during the course of ionizing radiation treatment of patients with head and neck tumor (HNTP. Samples from 21 HNTP and 24 healthy controls were isolated and identified. C. albicans isolated from two patients during radiotherapy were analyzed for virulence factors. Radiotherapy induced a higher level of both yeast colonization (81% vs 33% and non-albicans Candida (NAC colonization (52.4% vs 4.0% in HNTP than the control group. Patients were colonized by 5 different NAC species: C. glabrata, C. tropicalis, C. parapsilosis, C. krusei and C. kefir. On the other hand, C. albicans colonization was similar in patients and controls (6/21, 28.6% vs 7/24, 29.2%, respectively. Also, of the 11 patients assessed before and during radiotherapy, 5 (45.5% were colonized before the start of treatment and another 5 (45.5% during treatment. All of the latter were colonized by NAC species alone. Moreover, we observed a significant and continuous enhancement of C. albicans virulence as the radiotherapy progressed, in the two patients involved in this test. Thus, it is concluded that radiotherapy is an important predisposing factor for the oral candidiasis, including NAC species. Also, it may facilitate the development of more virulent C. albicans strains. Keywords: Candida. Radiotherapy. Virulence factor. Oral candidiasis.

  6. Tremor, the curious third wheel of fault motion (Invited)

    Science.gov (United States)

    Vidale, J. E.

    2009-12-01

    The known universe of tectonic fault behavior has gained a new neighborhood in the last few years. Before, faults were considered to either conform to the reasonably well-understood earthquake cycle or else slide steadily. In the earthquake cycle, a fault stays locked for the years while stress is accumulating, then cracks and slides, releasing about 0.1-10 MPa of the stress on the fault. The crack spreads across the fault at roughly the shear wave velocity, kilometers per second. Sliding across the crack occurs at rates on the order of a meter per second. Deeper than the locked portion, faults were assumed to move stealthily and steadily. Disrupting this orderly bipartite universe has been tremor - a prolonged, noise-like, 1-10 Hz rumbling that has been spotted below the locked portion of a variety of faults. In subduction zones, often tremor is coincident with slow and low-stress-drop slip that takes many orders of magnitude longer to complete than garden-variety earthquakes, with the rupture progression estimated in km per day rather than per second. The so-called episodic tremor and slip (ETS) is seen to strike at much more regular intervals than old-fashioned quakes. Speculation and disjoint observations abound. Probably the observations represent just the most easily observed portions of a process that moves with power at all frequencies. The spectrum of tremor radiation is less “red” than that of earthquakes for periods shorter than their duration. Near-lithostatic pore pressure may play an important role in lubricating ETS activity. ETS activity appears generally restricted to only some major faults. Strong passing surface waves from distant great earthquakes trigger pulsations of tremor. Strong nearby earthquakes can cause weeks of stronger than normal tremor. The ebb and flow of diurnal tides cause a rise and fall in tremor amplitude. Tremor can contain earthquake-like short bursts of energy, even dozens of discrete pops, all with the less red spectra

  7. 35 Cascadia Episodic Tremor and Slip events observed on GPS, seismic, and strain/tiltmeter arrays

    Science.gov (United States)

    Melbourne, T. I.; Aguiar, A. C.; Santillan, V. M.; Szeliga, W.; Miller, M.

    2007-12-01

    Several rapidly expanding GPS networks along the greater Cascadia forearc have enabled identification of 36 isolated Episodic Tremor and Slip (ETS) events since 1997, including two in 2007. ETS events are observed throughout the forearc, from northern California to southwestern British Columbia, with station density generally increasing towards the north. Events located in well-instrumented regions can be tracked as they migrate laterally north-south along the plate boundary, but increasing station density has resolved many smaller transients that could not previously be confidently identified. At the specific latitude of the northern Washington State and southwestern British Columbia, the 14-month average recurrence interval still holds true, 5 events after first recognition. Elsewhere, this periodicity is not observed. Along central Vancouver Island, a host of smaller events distinct from the 14-month recurrence occur with an aperiodic fashion. Sporadic smaller events also appear throughout the subduction zone to the south, including within the region known for the 14-month periodicity. In southern Washington State, some of the largest transient displacements are observed, but lack any obvious periodicity in their recurrence. Along central Oregon, an 18-month recurrence is evident, while in northern California (Yreka) the 11-month periodicity previously documented still holds true. We invert estimated GPS offsets for the largest 14 events using non-negative thrust faulting along a plate interface divided into roughly 500 subfaults. Those events have equivalent moment magnitudes ranging from 6.3 (smallest resolvable with GPS) to 6.8, and typically 2-3 cm of slip. The largest spatial extent of the events resolved to date is just under 500 km along strike, and maximum duration is seven weeks, which lies in marked contrast to other subduction zones. Averaged over many ETS events, the upper limit of transient slip in the vicinity of Seattle, WA lies just west of the

  8. Evaluation of Non-Volcanic Tremor Detection Techniques

    Science.gov (United States)

    Sit, S. M.; Brudzinski, M. R.; Kao, H.

    2009-12-01

    Non-volcanic tremor (NVT) is a subduction zone process often associated with the transition from stick-slip to stable sliding on the plate interface. In Northern Cascadia, NVT episodes lasting multiple weeks have been correlated spatially and temporally with slow slip episodes at a regular recurrence interval of 15±2 months. However, NVT across the entire Cascadia margin varies widely in recurrence and duration, while still other subduction zones (Japan, Mexico) observe separate cases of tremor and GPS-detected slip. Multiple identification and location techniques exist, but we will focus on techniques that can identify NVT at single stations to accommodate searching outside a dense network of instruments. This study evaluates these techniques in several regions along the entire Cascadia margin and in the Oaxaca segment of the Middle America Subduction Zone. Tremor signals are collected from a mixture of seismometers including those of temporary deployments targeting NVT, the EarthScope Transportable Array, the Canadian National Seismograph Network, and a few other regional networks that span the subduction zones. We compare existing techniques that scan moving averages, scintillation index, and hourly mean amplitudes with a new tremor frequency scanning technique that bandpass filters seismic data into three categories, 10-15 Hz, 2-5 Hz, and 0.2-0.5 Hz, where we expect prominent signals from microseismicity, NVT, and surface waves, respectively. Applying these techniques to episodes over the last few years finds that each technique can identify large, multi-week tremor events associated with GPS recorded slow slip. However, different techniques result in different totals of tremor hours detected per episode, as well as variable numbers of additional smaller episodes identified. Based on previous research that finds the amount of tremor correlated to the amount of slip from geodetic inversions, we are working towards a consensus single station approach that is

  9. Depressive symptoms can amplify embarrassment in essential tremor.

    Science.gov (United States)

    Louis, Elan D; Cosentino, Stephanie; Huey, Edward D

    2016-01-01

    Embarrassment can be a considerable problem for patients with essential tremor (ET) and is a major motivator for treatment. Depression is also a common feature of ET; as many as 35 % of patients report moderate to severe depressive symptoms. Our goal was to assess the associations between these motor and psychosocial factors (tremor, depression, embarrassment) in ET, with a particular interest in more fully assessing the possible association between depression and embarrassment. Ninety one ET cases (age 70.4 ± 12.8 years) enrolled in a prospective, clinical-epidemiological study. Depressive symptoms were assessed with the Center for Epidemiological Studies Depression Scale (CESD-10, 0-30 [maximum]), embarrassment, with the Essential Tremor Embarrassment Assessment (ETEA, 0-70 [maximum]), and action tremor, with a detailed in-person neurological examination. Higher CESD-10 score was significantly associated with higher ETEA score (p = 0.005), but not with increasing tremor severity (p = 0.94). In stratified analyses, cases with no or minimal depressive symptoms had the lowest ETEA scores, cases with moderate depressive symptoms had intermediate ETEA scores, and cases with severe depressive symptoms had the highest ETEA scores (p = 0.01). Furthermore, at each level of tremor severity, cases with more depressive symptoms had more embarrassment. Depressive symptoms seem to be more than a secondary response to the tremor in ET; they seem to amplify the level of embarrassment and, in addition to their own importance, seem to be a driver of other important clinical outcomes. Earlier treatment of depressive symptoms in ET patients could lessen the burden of secondary embarrassment.

  10. Comparison of PCT, CRP, D-Dimer, Lactate, TNF-α, IL-1β, IL-6 and lL-10 in Development of Systemic Inflammatory Response Syndrome and Sepsis on Patients with Isolated Head Trauma and Polytrauma

    Directory of Open Access Journals (Sweden)

    Emine Dağlı

    2012-12-01

    Full Text Available Objective: In this study, it was aimed to compare the relationship between Glasgow Coma Scale (GKS, ISS values, PCT, CRP, D-Dimer, laktat, TNF-α, IL-1β, IL-6, IL-10 in patients with polytrauma and isolated head trauma in conjunction with SIRS and sepsis. Material and Method: Total of 68 patients (32 polytrauma, 36 isolated head trauma aged between 18-65 years were enrolled in the study. For 7 days of follow up, the biochemical parameters were analysed on the days 0, 1, 3, 5, 7 and the ISS, GCS score and growth rates of SIRS and sepsis were recorded. Results: It was demonstrated that for patients with isolated head trauma, SIRS (80.6%, sepsis (38.9% and mortality values (71.4% were higher and there is a statistically important linear and inverse relationship between ISS and GCS values (p<0.05. During sepsis and SIRS phases, CRP elevated in both groups, whereas PCT only in the polytrauma group. D-Dimer values were investigated high in both groups, but atypically decreased on day 3 in isolated head trauma group. Lactate, TNF-α and, IL-1β were within reference values, IL-6 and IL-10 values were elevated in both groups but were higher in the polytrauma group. Conclusion: Although multiple variations were detected in serum markers of pro-inflamatory and acute phase proteins, we thought that these are inadequate in predicting mortality and complications such as SIRS and sepsis.

  11. Isolated adrenocorticotropic hormone deficiency associated with Hashimoto's disease and thyroid crisis triggered by head trauma. Case report.

    Science.gov (United States)

    Tanei, Takafumi; Eguchi, Youko; Yamamoto, Yuka; Hirano, Masaki; Takebayashi, Shigenori; Nakahara, Norimoto

    2012-01-01

    A 47-year-old man presented to our hospital after suffering transient loss of consciousness and falling to the floor. On admission, his Glasgow Coma Scale score was 11 (E3V3M5), and he exhibited restlessness. Blood examination revealed hyperthyroidism. Computed tomography showed slight traumatic subarachnoid hemorrhage. He developed fever and tachycardia, and was diagnosed with thyroid crisis. Magnetic resonance imaging showed a brain contusion in the right frontal lobe, and encephalopathy signs in the right frontal and insular cortex. Immunocytochemical examinations suggested Hashimoto's disease, and hormone examinations revealed plasma levels were undetectably low of adrenocorticotropic hormone (ACTH) and low of cortisol. Pituitary stimulation tests showed inadequate plasma ACTH and cortisol response, consistent with isolated ACTH deficiency (IAD). The final diagnosis was IAD associated with Hashimoto's disease. Hydrocortisone replacement therapy was continued, and the patient was nearly free from neurological deficits after 18 months. The neuroimaging abnormalities gradually improved with time.

  12. Tremor frequency characteristics in Parkinson's disease under resting-state and stress-state conditions.

    Science.gov (United States)

    Lee, Hong Ji; Lee, Woong Woo; Kim, Sang Kyong; Park, Hyeyoung; Jeon, Hyo Seon; Kim, Han Byul; Jeon, Beom S; Park, Kwang Suk

    2016-03-15

    Tremor characteristics-amplitude and frequency components-are primary quantitative clinical factors for diagnosis and monitoring of tremors. Few studies have investigated how different patient's conditions affect tremor frequency characteristics in Parkinson's disease (PD). Here, we analyzed tremor characteristics under resting-state and stress-state conditions. Tremor was recorded using an accelerometer on the finger, under resting-state and stress-state (calculation task) conditions, during rest tremor and postural tremor. The changes of peak power, peak frequency, mean frequency, and distribution of power spectral density (PSD) of tremor were evaluated across conditions. Patients whose tremors were considered more than "mild" were selected, for both rest (n=67) and postural (n=25) tremor. Stress resulted in both greater peak powers and higher peak frequencies for rest tremor (pcharacteristics, namely a lower frequency as amplitude increases, are different in stressful condition. Patient's conditions directly affect neural oscillations related to tremor frequencies. Therefore, tremor characteristics in PD should be systematically standardized across patient's conditions such as attention and stress levels.

  13. Motor imagery evokes increased somatosensory activity in Parkinson's disease patients with tremor.

    Science.gov (United States)

    Helmich, Rick C; Bloem, Bastiaan R; Toni, Ivan

    2012-08-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and whether these differences relate to the cerebral circuit producing tremor. We compared 18 PD patients with marked tremor, 20 PD patients without tremor, and 19 healthy controls. Subjects performed a controlled motor imagery task during fMRI scanning. We quantified imagery-related cerebral activity by contrasting imagery of biomechanically difficult and easy movements. Tremor-related activity was identified by relating cerebral activity to fluctuations in tremor amplitude, using electromyography during scanning. PD patients with tremor had better behavioral performance than PD patients without tremor. Furthermore, tremulous PD patients showed increased imagery-related activity in somatosensory area 3a, as compared with both healthy controls and to nontremor PD patients. This effect was independent from tremor-related activity, which was localized to the motor cortex, cerebellum, and thalamic ventral intermediate nucleus (VIM). The VIM, with known projections to area 3a, was unique in showing both tremor- and imagery-related responses. We conclude that parkinsonian tremor influences motor imagery by modulating central somatosensory processing through the VIM. This mechanism may explain clinical differences between PD patients with and without tremor.

  14. The distributed somatotopy of tremor: a window into the motor system.

    Science.gov (United States)

    Helmich, Rick C

    2013-03-01

    The posterior ventrolateral thalamus (VLp) plays a crucial role in Parkinson's tremor and in essential tremor: deep brain stimulation (DBS) of the VLp effectively diminishes both tremor types. Previous research has shown tremor oscillations in the VLp, but the spatial extent and somatotopy of these oscillations remained unclear. In this issue of Experimental Neurology, Pedrosa and colleagues measured neuro-muscular coherence at multiple sites in the VLp of patients with essential tremor and Parkinson's disease using implanted DBS electrodes (Pedrosa et al., 2012). They found multiple tremor clusters within the VLp, with spatially distinct tremor clusters for antagonistic muscles, and in many patients also multiple distinct tremor clusters for a single muscle. Interestingly, this group previously showed similar effects for the STN in tremulous Parkinson's disease (Reck et al., 2009, 2010). Together, these studies suggest that the distribution of tremor clusters is a general organizational principle of tremor, being present in two different tremor pathologies, and in two different nodes of the motor system. The presence of multiple tremor clusters also fits with the distributed somatotopy of the healthy motor system. Therefore, a further conclusion of this study could be that tremor is caused by aberrant synchronization within an otherwise healthy network, brought about by different pathophysiological neural triggers.

  15. Extending Alaska's plate boundary: tectonic tremor generated by Yakutat subduction

    Science.gov (United States)

    Wech, Aaron G.

    2016-01-01

    The tectonics of the eastern end of the Alaska-Aleutian subduction zone are complicated by the inclusion of the Yakutat microplate, which is colliding into and subducting beneath continental North America at near-Pacific-plate rates. The interaction among these plates at depth is not well understood, and further east, even less is known about the plate boundary or the source of Wrangell volcanism. The drop-off in Wadati-Benioff zone (WBZ) seismicity could signal the end of the plate boundary, the start of aseismic subduction, or a tear in the downgoing plate. Further compounding the issue is the possible presence of the Wrangell slab, which is faintly outlined by an anemic, eastward-dipping WBZ beneath the Wrangell volcanoes. In this study, I performed a search for tectonic tremor to map slow, plate-boundary slip in south-central Alaska. I identified ∼11,000 tremor epicenters, which continue 85 km east of the inferred Pacific plate edge marked by WBZ seismicity. The tremor zone coincides with the edges of the downgoing Yakutat terrane, and tremors transition from periodic to continuous behavior as they near the aseismic Wrangell slab. I interpret tremor to mark slow, semicontinuous slip occurring at the interface between the Yakutat and North America plates. The slow slip region lengthens the megathrust interface beyond the WBZ and may provide evidence for a connection between the Yakutat slab and the aseismic Wrangell slab.

  16. Blinded placebo crossover study of gabapentin in primary orthostatic tremor.

    Science.gov (United States)

    Rodrigues, Julian P; Edwards, Dylan J; Walters, Susan E; Byrnes, Michelle L; Thickbroom, Gary W; Stell, Rick; Mastaglia, Frank L

    2006-07-01

    Primary orthostatic tremor (OT) is a rare but disabling condition characterized by leg tremor and feelings of instability during stance. Previous studies have reported a reduction in OT symptoms with gabapentin treatment. In this study, we report on the benefits of gabapentin treatment in a double-blind placebo-controlled crossover study of 6 OT patients. First, the maximally effective gabapentin dosage (600-2,700 mg/day) for each patient was determined during an initial dose-titration phase. Patients were then studied 7 days after drug withdrawal and again after two 2-week periods of treatment with either gabapentin or placebo, using force platform posturography to quantify postural sway and tremor. Other medications for OT were continued unchanged. Symptomatic response was assessed by a patient-rated severity scale and quality of life (QOL) questionnaire. All patients reported an increase in symptoms during the washout phase and symptom reduction (50%-75%) during gabapentin treatment. Tremor amplitude was reduced to 79% +/- 11% and sway area to 71% +/- 11% of the placebo state. QOL improved in all patients, no adverse drug effects were noted, and symptomatic benefit was maintained at follow-up (mean = 19 months). The findings confirm that gabapentin is an effective treatment for OT, reducing both tremor and postural instability and improving quality of life, and support its use as add-on or first-line therapy for OT.

  17. Altered Functional Connectivity in Essential Tremor

    Science.gov (United States)

    Benito-León, Julián; Louis, Elan D.; Romero, Juan Pablo; Hernández-Tamames, Juan Antonio; Manzanedo, Eva; Álvarez-Linera, Juan; Bermejo-Pareja, Félix; Posada, Ignacio; Rocon, Eduardo

    2015-01-01

    Abstract Essential tremor (ET) has been associated with a spectrum of clinical features, with both motor and nonmotor elements, including cognitive deficits. We employed resting-state functional magnetic resonance imaging (fMRI) to assess whether brain networks that might be involved in the pathogenesis of nonmotor manifestations associated with ET are altered, and the relationship between abnormal connectivity and ET severity and neuropsychological function. Resting-state fMRI data in 23 ET patients (12 women and 11 men) and 22 healthy controls (HC) (12 women and 10 men) were analyzed using independent component analysis, in combination with a “dual-regression” technique, to identify the group differences of resting-state networks (RSNs) (default mode network [DMN] and executive, frontoparietal, sensorimotor, cerebellar, auditory/language, and visual networks). All participants underwent a neuropsychological and neuroimaging session, where resting-state data were collected. Relative to HC, ET patients showed increased connectivity in RSNs involved in cognitive processes (DMN and frontoparietal networks) and decreased connectivity in the cerebellum and visual networks. Changes in network integrity were associated not only with ET severity (DMN) and ET duration (DMN and left frontoparietal network), but also with cognitive ability. Moreover, in at least 3 networks (DMN and frontoparietal networks), increased connectivity was associated with worse performance on different cognitive domains (attention, executive function, visuospatial ability, verbal memory, visual memory, and language) and depressive symptoms. Further, in the visual network, decreased connectivity was associated with worse performance on visuospatial ability. ET was associated with abnormal brain connectivity in major RSNs that might be involved in both motor and nonmotor symptoms. Our findings underscore the importance of examining RSNs in this population as a biomarker of disease. PMID:26656325

  18. A new familial disease of saccadic oscillations and limb tremor provides clues to mechanisms of common tremor disorders.

    Science.gov (United States)

    Shaikh, Aasef G; Miura, Kenichiro; Optican, Lance M; Ramat, Stefano; Leigh, R John; Zee, David S

    2007-11-01

    Tremor disorders pose fundamental questions about disease mechanisms, and challenges to successful neurotherapeutics: What causes motor circuits to oscillate in disorders in which the central nervous system otherwise seems normal? How does inheritance 'determine' the clinical phenotype in familial tremor disorders? Here, we address these questions. Analogies between the neural circuits controlling rapid eye movements (saccades) and those controlling limb movements allow us to translate the interpretations from the saccadic systems to the limb movement system. Moreover, the relatively well understood neurophysiology of the ocular motor system offers a unique opportunity to test specific hypotheses about normal and abnormal motor control of both eye and limb movements. We describe a new familial disorder--'micro-saccadic oscillations and limb tremor (microSOLT)'--in a mother and daughter who had tiny saccadic oscillations of the eyes and tremor of the hands. This unique oscillatory movement disorder resembles other common tremor disorders (such as essential tremor) that occur in patients who have an otherwise normally functioning central nervous system. We hypothesize that microSOLT is caused by an inherited abnormality that results in abnormal membrane properties causing reduced external inhibition in the premotor neurons that generate the high-frequency discharge (burst) for saccades and for ballistic limb movements. To test this hypothesis, we recorded hand tremor and eye movements in two patients with microSOLT and particularly during natural circumstances when inhibition of the premotor saccadic burst neurons is removed (e.g. eye closure). We then simulated a conductance-based model for the premotor commands which included excitatory and reciprocally inhibitory burst neurons. The structure of this physiologically realistic model was based upon known cell types and anatomical connections in the brainstem (for saccades) and the thalamus (for limb movements). The

  19. Isolation

    DEFF Research Database (Denmark)

    Agerholm, Frank Juul

    2011-01-01

    Næringsstoffet har i dette nummer sat fokus på ”velvære i vinterkulden”, ”indendørsaktiviteter” og ”fedtafgift”. I klummen vises det, at disse tre fokusområder, der for en umiddelbar betragtning måske nok synes noget uensartede, falder sammen i ét tema: Isolation!......Næringsstoffet har i dette nummer sat fokus på ”velvære i vinterkulden”, ”indendørsaktiviteter” og ”fedtafgift”. I klummen vises det, at disse tre fokusområder, der for en umiddelbar betragtning måske nok synes noget uensartede, falder sammen i ét tema: Isolation!...

  20. Time-frequency scale decomposition of tectonic tremor signals for space-time reconstruction of tectonic tremor sources

    Science.gov (United States)

    Poiata, N.; Satriano, C.; Vilotte, J. P.; Bernard, P.; Obara, K.

    2015-12-01

    Seismic radiation associated with transient deformations along the faults and subduction interfaces encompasses a variety of events, i.e., tectonic tremors, low-frequency earthquakes (LFE), very low-frequency earthquakes (VLFs), and slow-slip events (SSE), with a wide range of seismic moment and characteristic durations. Characterizing in space and time the complex sources of these slow earthquakes, and their relationship with background seismicity and large earthquakes generation, is of great importance for understanding the physics and mechanics of the processes of active deformations along the plate interfaces. We present here first developments towards a methodology for: (1) extracting the different frequency and scale components of observed tectonic tremor signal, using advanced time-frequency and time-scale signal representation such as Gabor transform scheme based on, e.g. Wilson bases or Modified Discrete Cosine Transform (MDCT) bases; (2) reconstructing their corresponding potential sources in space and time, using the array method of Poiata et al. (2015). The methodology is assessed using a dataset of tectonic tremor episodes from Shikoku, Japan, recorded by the Hi-net seismic network operated by NIED. We illustrate its performance and potential in providing activity maps - associated to different scale-components of tectonic tremors - that can be analyzed statistically to improve our understanding of tremor sources and scaling, as well as their relation with the background seismicity.

  1. Volcanic tremor and plume height hysteresis from Pavlof Volcano, Alaska.

    Science.gov (United States)

    Fee, David; Haney, Matthew M; Matoza, Robin S; Eaton, Alexa R; Cervelli, Peter; Schneider, David J; Iezzi, Alexandra M

    2017-01-06

    The March 2016 eruption of Pavlof Volcano, Alaska, produced an ash plume that caused the cancellation of more than 100 flights in North America. The eruption generated strong tremor that was recorded by seismic and remote low-frequency acoustic (infrasound) stations, including the EarthScope Transportable Array. The relationship between the tremor amplitudes and plume height changes considerably between the waxing and waning portions of the eruption. Similar hysteresis has been observed between seismic river noise and discharge during storms, suggesting that flow and erosional processes in both rivers and volcanoes can produce irreversible structural changes that are detectable in geophysical data. We propose that the time-varying relationship at Pavlof arose from changes in the tremor source related to volcanic vent erosion. This relationship may improve estimates of volcanic emissions and characterization of eruption size and intensity.

  2. Dynamic Variability of Isometric Action Tremor in Precision Pinching

    Directory of Open Access Journals (Sweden)

    Tim Eakin

    2012-01-01

    Full Text Available Evolutionary development of isometric force impulse frequencies, power, and the directional concordance of changes in oscillatory tremor during performance of a two-digit force regulation task was examined. Analyses compared a patient group having tremor confounding volitional force regulation with a control group having no neuropathological diagnosis. Dependent variables for tremor varied temporally and spatially, both within individual trials and across trials, across individuals, across groups, and between digits. Particularly striking findings were magnitude increases during approaches to cue markers and shifts in the concordance phase from pinching toward rigid sway patterns as the magnitude increased. Magnitudes were significantly different among trace line segments of the task and were characterized by differences in relative force required and by the task progress with respect to cue markers for beginning, reversing force change direction, or task termination. The main systematic differences occurred during cue marker approach and were independent of trial sequence order.

  3. Continental crust anisotropy measurements from tectonic tremor in Cascadia

    Science.gov (United States)

    Huesca-Pérez, Eduardo; Ortega, Roberto; Valenzuela, Raúl W.

    2017-05-01

    We present new observations of crustal anisotropy in the southern Cascadia fore arc from tectonic tremor. The abundance of tremor activity in Oregon and northern California during slow-slip events offers an enormous amount of information with which to measure and analyze anisotropy in the upper brittle continental crust. To accomplish this, we performed analyses of wave polarization and shear wave splitting of tectonic tremor signals by using three component broadband seismic stations. The splitting times range between 0.11 and 0.32 s and are consistent with typical values observed in the continental crust. Fast polarization azimuths are, in general, margin parallel and trend N-S, which parallels the azimuths of the maximum compressive stresses observed in this region. This pattern is likely to be controlled by the stress field. Comparatively, the anisotropic structure of fast directions observed in the northern section of the Cascadia margin is oblique with respect to the southern section of Cascadia, which, in general, trends E-W and is mainly controlled by active faulting and geological structures. Source distribution analysis using a bivariate normal distribution that expresses the distribution of tremors in a preferred direction shows that in northern California and Oregon, the population of tremors tends to distribute parallel to fast polarization azimuths and maximum compressive stresses, suggesting that both tremor propagation and anisotropy are influenced by the stress field. Results show that the anisotropy reflects an active tectonic process that involves the northward movement of the Oregon Block, which is rotating as a rigid body. In northern Cascadia, previous results of anisotropy show that the crust is undergoing a shortening process due to velocity differences between the Oregon Block and the North America plate, which is moving more slowly with respect to the Oregon Block, making it clash against Vancouver Island.

  4. Evolution of Tremor's Tidal Sensitivity Through the Slow Slip Cycle

    Science.gov (United States)

    Houston, H.

    2014-12-01

    Solid Earth and ocean loading tides generate stresses that modulate slow slip and tremor on deep plate boundaries. Analysis of the influence of tidal stress on 35000 tremors located in a northern Cascadia region that ruptures repeatedly in M6.5 to 6.8 slow earthquakes has yielded several new findings (Houston, 2014, subm.). Tremor sensitivity to tidal stress is low for the first day or so of activity at a spot, but increases progressively over a few days of slip at that spot, constraining the pace of weakening during ETS. After the first day or so, sensitivity varies exponentially with stress. Consideration of an isotropic pore pressure model allows an in-situ estimate of intrinsic friction on the deep subduction interface, yielding values far below lab values (i.e., mu et al, 2010). Inter-ETS tremor groups of several months duration show some sensitivity to tidal stress, although not as much as tremor during the late portions of ETS. Interestingly, I see an evolution during the 12-15 month interval between major ETSs. In particular, tidal sensitivity increases moderately toward the end of the interval as the fault is reloaded and the next large ETS is imminent. First-order features are consistent with extension of the above-mentioned model of threshold failure strength versus stress. The concept is that during the inter-ETS period, strength rebuilds as the logarithm of time (e.g., Vidale et al, 1994) since the last major ETS, while average shear or Coulomb stress on the plate interface rebuilds roughly linearly due to plate convergence. Tidal stresses become more effective in triggering tremor later in the cycle as the linearly-growing stress approaches the logarithmically-growing strength. This approach illuminates the competition between healing on the plate interface and reloading with tectonic stress, and can help constrain healing rate and conditions on the deep subduction interface.

  5. Task force report: Scales for screening and evaluating tremor: Critique and recommendations

    NARCIS (Netherlands)

    Elble, R.; Bain, P.; Forjaz, M. Joao; Haubenberger, D.; Testa, C.; Goetz, C.G.; Leentjens, A.F.; Martinez-Martin, P.; Traon, A. Pavy-Le; Post, B.; Sampaio, C.; Stebbins, G.T.; Weintraub, D.; Schrag, A.

    2013-01-01

    The Movement Disorder Society established a task force to review rating scales for the assessment of tremor. Screening instruments used in identifying patients with tremor were also reviewed. Seven tremor severity scales, six activities of daily living (ADL)/disability scales, four quality-of-life

  6. Limited correlations between clinician-based and patient-based measures of essential tremor severity

    NARCIS (Netherlands)

    van der Stouwe, A. M. M.; Broersma, M.; Buijink, A. W. G.; van Rootselaar, A. F.; Maurits, N. M.

    2015-01-01

    Introduction: We investigated the relation between changes in clinician-based and patient-based measures of tremor severity, within the Fahn-Tolosa-Marin Tremor Rating Scale (IRS) and Visual Analogue Scale (VAS) in essential tremor patients. Methods: Thirty-seven patients were assessed twice: on- an

  7. Task force report: Scales for screening and evaluating tremor: Critique and recommendations

    NARCIS (Netherlands)

    Elble, R.; Bain, P.; Forjaz, M. Joao; Haubenberger, D.; Testa, C.; Goetz, C.G.; Leentjens, A.F.; Martinez-Martin, P.; Traon, A. Pavy-Le; Post, B.; Sampaio, C.; Stebbins, G.T.; Weintraub, D.; Schrag, A.

    2013-01-01

    The Movement Disorder Society established a task force to review rating scales for the assessment of tremor. Screening instruments used in identifying patients with tremor were also reviewed. Seven tremor severity scales, six activities of daily living (ADL)/disability scales, four quality-of-life s

  8. Tremor Detection Using Parametric and Non-Parametric Spectral Estimation Methods : A Comparison with Clinical Assessment

    NARCIS (Netherlands)

    Martinez Manzanera, Octavio; Elting, Jan Willem; van der Hoeven, Johannes H; Maurits, Natasha M

    2016-01-01

    In the clinic, tremor is diagnosed during a time-limited process in which patients are observed and the characteristics of tremor are visually assessed. For some tremor disorders, a more detailed analysis of these characteristics is needed. Accelerometry and electromyography can be used to obtain a

  9. ‘YES YES HEAD TREMOR’ case developing after cerebellar infarction

    Directory of Open Access Journals (Sweden)

    Uygar Utku

    2015-12-01

    Full Text Available Movement disorders, developing after cerebellar infarctions, are rare. One of them is 'Yes / Yes tremor' head tremor. A 73-year-old female patient was brought to the emergency department of our hospital with complaints of dizziness, nausea and vomiting. There was hypertension on her past history. She was taking anti-hypertension drug. Her neurological examination was normal except for right dysmetria, disdiadikokinesia and damaged knee-heel test. Electrocardiography was atrial fibrillation with rapid ventricular response. On the right cerebellar hemisphere, brain computerized tomography revealed consistent lesions with acute ischemic stroke. The patient showed clinically significant improvement in time and discharged with coumadine. When she came for drug control after two weeks, we detected her ‘Yes / Yes’ revealed style of head tremor started three days ago. The tremor was resting-postural. Its activity increased with excitement, decreased after resting and stopped while sleeping. She was intolerant although we initiated the treatment with primidone 250 mg tablets divided into eight. After continuing the treatment with gabapentine titrated 300 mg tablets, the head tremor of patient improved remarkedly in a short period of time. The phenomenon is presented due to its rarity and remarkableness.

  10. Methodological issues in clinical drug development for essential tremor.

    Science.gov (United States)

    Carranza, Michael A; Snyder, Madeline R; Elble, Rodger J; Boutzoukas, Angelique E; Zesiewicz, Theresa A

    2012-01-01

    Essential tremor (ET) is one of the most common tremor disorders in the world. Despite this, only two medications have received Level A recommendations from the American Academy of Neurology to treat it (primidone and propranolol). Even though these medications provide relief to a large group of ET patients, up to 50% of patients are non-responders. Additional medications to treat ET are needed. This review discusses some of the methodological issues that should be addressed for quality clinical drug development in ET.

  11. The balance and gait disorder of essential tremor: what does this mean for patients?

    Science.gov (United States)

    Arkadir, David; Louis, Elan D

    2013-07-01

    Essential tremor (ET), once considered a monosymptomatic disease, is now viewed as a syndrome characterized by action tremor as well as a variety of other neurological features. These features include deficits of both balance (i.e. the ability to maintain the body within its base of support) and gait. Balance and gait abnormalities in ET have been studied most extensively in the laboratory, with the disability and burden on life, as experienced by patients with ET, being a subject of relatively less scrutiny. In this paper, we review the data on balance and gait impairment in ET. These include data both from objective assessments (bedside examination or laboratory gait analysis) and subjective assessments (patients' reports of imbalance). We discuss the clinical implications of the current data, and suggest a tiered approach to begin to address the still unanswered questions in this field. This tiered approach starts with an attempt to isolate a subpopulation of patients who are at greatest risk of difficulty with balance and gait, and then later focuses on this subgroup to assess the burden of any balance and gait impairments as well as the impact of potential therapeutic interventions.

  12. Knowledge gaps and research recommendations for essential tremor

    NARCIS (Netherlands)

    Hopfner, F.; Haubenberger, D.; Galpern, W.R.; Gwinn, K.; Veer, A. van der; White, S.; Bhatia, K.; Adler, C.H.; Eidelberg, D.; Ondo, W.; Stebbins, G.T.; Tanner, C.M.; Helmich, R.C.G.; Lenz, F.A.; Sillitoe, R.V.; Vaillancourt, D.; Vitek, J.L.; Louis, E.D.; Shill, H.A.; Frosch, M.P.; Foroud, T.; Kuhlenbaumer, G.; Singleton, A.; Testa, C.M.; Hallett, M.; Elble, R.; Deuschl, G.

    2016-01-01

    Essential tremor (ET) is a common cause of significant disability, but its etiologies and pathogenesis are poorly understood. Research has been hampered by the variable definition of ET and by non-standardized research approaches. The National Institute of Neurological Disorders and Stroke (USA)

  13. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS)

    Science.gov (United States)

    ... but almost always with less severity. Most affected women have some degree of tremor and/or ataxia. While the psychiatric and mood disorders are also less frequent in females, they are at higher risk for anxiety and depression in general. Additional symptoms affecting some ...

  14. Rhythmic finger tapping reveals cerebellar dysfunction in essential tremor

    NARCIS (Netherlands)

    Buijink, A. W. G.; Broersma, M.; van der Stouwe, A. M. M.; van Wingen, G. A.; Groot, P. F. C.; Speelman, J. D.; Maurits, N. M.; van Rootselaar, A. F.

    2015-01-01

    Introduction: Cerebellar circuits are hypothesized to play a central role in the pathogenesis of essential tremor. Rhythmic finger tapping is known to strongly engage the cerebellar motor circuitry. We characterize cerebellar and, more specifically, dentate nucleus function, and neural correlates of

  15. Semidominant heridity of absence-like seizures in tremor rat.

    Institute of Scientific and Technical Information of China (English)

    CaiJi-qun; KumatoshiIshihara; RyosukeHanaya; YoshihiroKiura; KaoruKurisu; TadaoSerikawa; MasashiSasa

    2004-01-01

    The tremor rat (tm/tm) exhibits absence-like seizures characterized by 5 -7 Hz spike-wave complexes in cortical and hippocampal EEG. Recently, the TM rat has been found to be devoid of the asp) artoacylase (asp gene responsible for metabolizing N-acetyl aspartate. Electrophysiological studies were performed to determine whether the tm gene was

  16. Dementia in Fragile X-associated Tremor/Ataxia Syndrome

    Directory of Open Access Journals (Sweden)

    Ricardo Nitrini

    Full Text Available Abstract Fragile X-associated tremor/ataxia syndrome (FXTAS is a cause of movement disorders and cognitive decline which has probably been underdiagnosed, especially if its prevalence proves similar to those of progressive supranuclear palsy and amyotrophic lateral sclerosis. We report a case of a 74-year-old man who presented with action tremor, gait ataxia and forgetfulness. There was a family history of tremor and dementia, and one of the patient's grandsons was mentally deficient. Neuropsychological evaluation disclosed a frontal network syndrome. MRI showed hyperintensity of both middle cerebellar peduncles, a major diagnostic hallmark of FXTAS. Genetic testing revealed premutation of the FMR1 gene with an expanded (CGG90 repeat. The diagnosis of FXTAS is important for genetic counseling because the daughters of the affected individuals are at high risk of having offspring with fragile X syndrome. Tremors and cognitive decline should raise the diagnostic hypothesis of FXTAS, which MRI may subsequently reinforce, while the detection of the FMR1 premutation can confirm the condition.

  17. Online tremor suppression using electromyography and low-level electrical stimulation.

    Science.gov (United States)

    Dosen, Strahinja; Muceli, Silvia; Dideriksen, Jakob Lund; Romero, Juan Pablo; Rocon, Eduardo; Pons, Jose; Farina, Dario

    2015-05-01

    Tremor is one of the most prevalent movement disorders. There is a large proportion of patients (around 25%) in whom current treatments do not attain a significant tremor reduction. This paper proposes a tremor suppression strategy that detects tremor from the electromyographic signals of the muscles from which tremor originates and counteracts it by delivering electrical stimulation to the antagonist muscles in an out of phase manner. The detection was based on the iterative Hilbert transform and stimulation was delivered above the motor threshold (motor stimulation) and below the motor threshold (sensory stimulation). The system was tested on six patients with predominant wrist flexion/extension tremor (four with Parkinson disease and two with Essential tremor) and led to an average tremor reduction in the range of 46%-81% and 35%-48% across five patients when using the motor and sensory stimulation, respectively. In one patient, the system did not attenuate tremor. These results demonstrate that tremor attenuation might be achieved by delivering electrical stimulation below the motor threshold, preventing muscle fatigue and discomfort for the patients, which sets the basis for the development of an alternative treatment for tremor.

  18. Evaluating machine learning algorithms estimating tremor severity ratings on the Bain-Findley scale

    Science.gov (United States)

    Yohanandan, Shivanthan A. C.; Jones, Mary; Peppard, Richard; Tan, Joy L.; McDermott, Hugh J.; Perera, Thushara

    2016-12-01

    Tremor is a debilitating symptom of some movement disorders. Effective treatment, such as deep brain stimulation (DBS), is contingent upon frequent clinical assessments using instruments such as the Bain-Findley tremor rating scale (BTRS). Many patients, however, do not have access to frequent clinical assessments. Wearable devices have been developed to provide patients with access to frequent objective assessments outside the clinic via telemedicine. Nevertheless, the information they report is not in the form of BTRS ratings. One way to transform this information into BTRS ratings is through linear regression models (LRMs). Another, potentially more accurate method is through machine learning classifiers (MLCs). This study aims to compare MLCs and LRMs, and identify the most accurate model that can transform objective tremor information into tremor severity ratings on the BTRS. Nine participants with upper limb tremor had their DBS stimulation amplitude varied while they performed clinical upper-extremity exercises. Tremor features were acquired using the tremor biomechanics analysis laboratory (TREMBAL). Movement disorder specialists rated tremor severity on the BTRS from video recordings. Seven MLCs and 6 LRMs transformed TREMBAL features into tremor severity ratings on the BTRS using the specialists’ ratings as training data. The weighted Cohen’s kappa ({κ\\text{w}} ) defined the models’ rating accuracy. This study shows that the Random Forest MLC was the most accurate model ({κ\\text{w}}   =  0.81) at transforming tremor information into BTRS ratings, thereby improving the clinical interpretation of tremor information obtained from wearable devices.

  19. Using a smart phone as a standalone platform for detection and monitoring of pathological tremors.

    Science.gov (United States)

    Daneault, Jean-François; Carignan, Benoit; Codère, Carl Éric; Sadikot, Abbas F; Duval, Christian

    2012-01-01

    Smart phones are becoming ubiquitous and their computing capabilities are ever increasing. Consequently, more attention is geared toward their potential use in research and medical settings. For instance, their built-in hardware can provide quantitative data for different movements. Therefore, the goal of the current study was to evaluate the capabilities of a standalone smart phone platform to characterize tremor. Algorithms for tremor recording and online analysis can be implemented within a smart phone. The smart phone provides reliable time- and frequency-domain tremor characteristics. The smart phone can also provide medically relevant tremor assessments. Smart phones have the potential to provide researchers and clinicians with quantitative short- and long-term tremor assessments that are currently not easily available. A smart phone application for tremor quantification and online analysis was developed. Then, smart phone results were compared to those obtained simultaneously with a laboratory accelerometer. Finally, results from the smart phone were compared to clinical tremor assessments.

  20. Tremor and its duration-amplitude distribution at Popocatépetl volcano, Mexico

    Science.gov (United States)

    Arámbula-Mendoza, R.; Valdés-González, C.; Varley, N.; Reyes-Pimentel, T. A.; Juárez-García, B.

    2016-09-01

    The duration-amplitude distribution was calculated for the tremor observed at Popocatépetl volcano during episodes of activity in 2000 and 2012-2014. An exponential function was used to obtain a good fit for the duration-amplitude distribution, and the source of volcanic tremor is probably generated by the transportation of magmatic fluids and its coupling with the host rock within the volcanic conduit. In particular, harmonic tremor has shown large amplitudes, durations, and mean values of amplitude, more than spasmodic or pulsating tremor. This is due to different generation mechanisms: in the case of harmonic tremor, it is produced during magma ascent and lava dome growth, while spasmodic and pulsating tremors are associated with fragmentation of the lava dome and gas emissions. This paper presents the duration-amplitude distribution as a method to estimate the intensity of the tremor at Popocatépetl, a volcano with the major risk in all Mexico.

  1. Tremor in X-linked recessive spinal and bulbar muscular atrophy (Kennedy's disease

    Directory of Open Access Journals (Sweden)

    Francisco A. Dias

    2011-01-01

    Full Text Available OBJECTIVE: To study tremor in patients with X-linked recessive spinobulbar muscular atrophy or Kennedy's disease. METHODS: Ten patients (from 7 families with a genetic diagnosis of Kennedy's disease were screened for the presence of tremor using a standardized clinical protocol and followed up at a neurology outpatient clinic. All index patients were genotyped and showed an expanded allele in the androgen receptor gene. RESULTS: Mean patient age was 37.6 years and mean number of CAG repeats 47 (44-53. Tremor was present in 8 (80% patients and was predominantly postural hand tremor. Alcohol responsiveness was detected in 7 (88% patients with tremor, who all responded well to treatment with a β-blocker (propranolol. CONCLUSION: Tremor is a common feature in patients with Kennedy's disease and has characteristics similar to those of essential tremor.

  2. Automated detection and characterization of harmonic tremor in continuous seismic data

    Science.gov (United States)

    Roman, Diana C.

    2017-06-01

    Harmonic tremor is a common feature of volcanic, hydrothermal, and ice sheet seismicity and is thus an important proxy for monitoring changes in these systems. However, no automated methods for detecting harmonic tremor currently exist. Because harmonic tremor shares characteristics with speech and music, digital signal processing techniques for analyzing these signals can be adapted. I develop a novel pitch-detection-based algorithm to automatically identify occurrences of harmonic tremor and characterize their frequency content. The algorithm is applied to seismic data from Popocatepetl Volcano, Mexico, and benchmarked against a monthlong manually detected catalog of harmonic tremor events. During a period of heightened eruptive activity from December 2014 to May 2015, the algorithm detects 1465 min of harmonic tremor, which generally precede periods of heightened explosive activity. These results demonstrate the algorithm's ability to accurately characterize harmonic tremor while highlighting the need for additional work to understand its causes and implications at restless volcanoes.

  3. Non-Volcanic Tremor Observed in Guerrero, Mexico

    Science.gov (United States)

    Payero, J.; Kostoglodov, V.; Shapiro, N.; Mikumo, T.; Iglesias, A.; Perez, X.; Clayton, R.

    2007-12-01

    Non-volcanic tremor (NVT) activity is clearly identified as episodes of higher spectral amplitude in the range of 1-8 Hz in daily spectrograms from the continuous records at broad band seismic stations in the Guerrero state, Mexico. The analyzed data cover a period of 2001-2007 when in 2001-2002 a large slow slip event (SSE) had occurred in the Guerrero-Oaxaca region, and then followed by a steady-state interseismic epoch of 2003-2005 and a new large SSE occurred in 2006. The tremor signals in Mexico are very similar to those obtained in Cascadia subduction zone. An average tremor burst remains for 10-60 min and is dominated by S-waves. More than 100 strong NVT bursts were recorded by the most of the Meso-American Subduction Experiment (MASE 2005-2007) seismic stations with the majority of epicenters clustered in the narrow band of ~40 x 150 km2 to the south of Iguala city and in parallel to the coastline. Depths of NVT hypocenters are poorly constrained but mostly scattered in the continental crust between 5 and 45 km depth. Tremor activity is significantly higher during the 2001-2002 and 2006 SSE compared with that for the "quiet" period of 2003-2005. Very low NVT occurrence for the period of about 2 months right after the SSE is apparent in 2002 and 2006. Similar to the Japan and Cascadia subduction zones, the main tremor activity in Mexico develops in the area close to the mantle wedge. In Mexico it is located at approximately 200 km inland from the trench. While conductivity pattern obtained from the magnetotelluric profile in Guerrero does not correlate directly with the NVT distribution, gravity and magnetic anomalies modeling favors a hypothesis that the NVT is apparently related to the dehydration and serpentinization processes.

  4. Non-invasive Brain Stimulation for Essential Tremor

    Science.gov (United States)

    Shih, Ludy C.; Pascual-Leone, Alvaro

    2017-01-01

    Background There is increasing interest in the use of non-invasive brain stimulation to characterize and potentially treat essential tremor (ET). Studies have used a variety of stimulation coils, paradigms, and target locations to make these observations. We reviewed the literature to compare prior studies and to evaluate the rationale and the methods used in these studies. Methods We performed a systematic literature search of the PubMed database using the terms “transcranial,” “noninvasive,” “brain stimulation,” “transcranial magnetic stimulation (TMS),” “transcranial direct current stimulation (tDCS),” “transcranial alternating current stimulation (tACS),” and “essential tremor.” Results Single pulses of TMS to the primary motor cortex have long been known to reset tremor. Although there are relatively few studies showing alterations in motor cortical physiology, such as motor threshold, short and long intracortical inhibition, and cortical silent period, there may be some evidence of altered intracortical facilitation and cerebello-brain inhibition in ET. Repetitive TMS, theta burst stimulation, tDCS, and tACS have been applied to human subjects with tremor with some preliminary signs of tremor reduction, particularly in those studies that employed consecutive daily sessions. Discussion A variety of stimulation paradigms and targets have been explored, with the increasing rationale an interest in targeting the cerebellum. Rigorous assessment of coil geometry, stimulation paradigm, rationale for selection of the specific anatomic target, and careful phenotypic and physiologic characterization of the subjects with ET undergoing these interventions may be critical in extending these preliminary findings into effective stimulation therapies. PMID:28373927

  5. The radiation of surface wave energy: Implications for volcanic tremor

    Science.gov (United States)

    Haney, M. M.; Denolle, M.; Lyons, J. J.; Nakahara, H.

    2015-12-01

    The seismic energy radiated by active volcanism is one common measurement of eruption size. For example, the magnitudes of individual earthquakes in volcano-tectonic (VT) swarms can be summed and expressed in terms of cumulative magnitude, energy, or moment release. However, discrepancies exist in current practice when treating the radiated energy of volcano seismicity dominated by surface waves. This has implications for volcanic tremor, since eruption tremor typically originates at shallow depth and is made up of surface waves. In the absence of a method to compute surface wave energy, estimates of eruption energy partitioning between acoustic and seismic waves typically assume seismic energy is composed of body waves. Furthermore, without the proper treatment of surface wave energy, it is unclear how much volcanic tremor contributes to the overall seismic energy budget during volcanic unrest. To address this issue, we derive, from first principles, the expression of surface wave radiated energy. In contrast with body waves, the surface wave energy equation is naturally expressed in the frequency domain instead of the time domain. We validate our result by reproducing an analytical solution for the radiated power of a vertical force source acting on a free surface. We further show that the surface wave energy equation leads to an explicit relationship between energy and the imaginary part of the surface wave Green's tensor at the source location, a fundamental property recognized within the field of seismic interferometry. With the new surface wave energy equation, we make clear connections to reduced displacement and propose an improved formula for the calculation of surface wave reduced displacement involving integration over the frequency band of tremor. As an alternative to reduced displacement, we show that reduced particle velocity squared is also a valid physical measure of tremor size, one based on seismic energy rate instead of seismic moment rate. These

  6. Task force report: scales for screening and evaluating tremor: critique and recommendations.

    Science.gov (United States)

    Elble, Rodger; Bain, Peter; Forjaz, Maria João; Haubenberger, Dietrich; Testa, Claudia; Goetz, Christopher G; Leentjens, Albert F G; Martinez-Martin, Pablo; Pavy-Le Traon, Anne; Post, Bart; Sampaio, Cristina; Stebbins, Glenn T; Weintraub, Daniel; Schrag, Anette

    2013-11-01

    The Movement Disorder Society established a task force to review rating scales for the assessment of tremor. Screening instruments used in identifying patients with tremor were also reviewed. Seven tremor severity scales, six activities of daily living (ADL)/disability scales, four quality-of-life scales, and five screening instruments were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and sensitivity to change were reviewed for each scale; and each scale was classified as recommended, suggested or listed based on whether 3, 2, or 1 of the following criteria were met: (1) used in the assessment of tremor (yes/no), (2) used in published studies by people other than the developers (yes/no), and (3) successful clinimetric testing (yes/no). Five tremor severity scales (the Fahn-Tolosa-Marin Tremor Rating Scale, the Bain and Findley Clinical Tremor Rating Scale, the Bain and Findley Spirography Scale, the Washington Heights-Inwood Genetic Study of Essential Tremor Rating Scale, and the Tremor Research Group Essential Tremor Rating Assessment Scale), one ADL/disability scale (the Bain and Findley Tremor ADL Scale), one quality-of-life scale (the Quality of Life in Essential Tremor Questionnaire), and one screening instrument (the Washington Heights-Inwood Genetic Study of Essential Tremor Rating Scale, version 1) are recommended using these criteria. However, all scales need a more comprehensive analysis of sensitivity to change in order to judge their utility in clinical trials and individual patient assessments. The task force recommends that further work with existing recommended scales be performed as opposed to the development of new tremor scales.

  7. In vitro effects of metals on isolated head-kidney and blood leucocytes of the teleost fish Sparus aurata L. and Dicentrarchus labrax L.

    Science.gov (United States)

    Morcillo, Patricia; Meseguer, José; Esteban, M Ángeles; Cuesta, Alberto

    2016-07-01

    The in vitro use of fish leucocytes to test the toxicity of aquatic pollutants, and particularly the immutoxicological effects, could be a valuable alternative to fish bioassays but has received little attention. In this study, head-kidney and peripheral blood leucocytes (HKLs and PBLs, respectively) from gilthead seabream (Sparus aurata L.) and European sea bass (Dicentrarchus labrax L.) specimens were exposed to Cd, MeHg (methylmercury), Pb or As for 24 h being evaluated the resulting cytotoxicity. Exposure to metals produced a dose-dependent reduction in the viability, and MeHg showed the highest toxicity followed by Cd, As and Pb. Interestingly, leucocytes from European sea bass are more resistant to metal exposure than those from gilthead seabream. Similarly, HKLs are always more sensitive than those isolated from blood from the same fish species. Moreover, fish leucocytes incubated with metals exhibited alterations in gene expression profiles that were more pronounced in the HKLs in general, being Pb the metal provoking less effects. Concretely, genes related to cellular protection (metallothionein), stress (heat shock protein 70) and oxidative stress (superoxide dismutase, catalase and glutathione reductase) were, in general, down-regulated in seabream HKLs but up-regulated in seabream PBLs and sea bass HKLs and PBLs. In addition, this profile leads to the increase of expression in genes related to apoptosis (Bcl2 associated X protein and caspase 3). Finally, transcription of genes involved in immunity (interleukin-1β and immunoglobulin M) was down-regulated, mainly in seabream leucocytes. This study points to the benefits for evaluating the toxicological mechanisms of marine pollution using fish leucocytes in vitro and insight into the mechanisms at gene level.

  8. Hydrolyzed fish proteins modulates both inflammatory and antioxidant gene expression as well as protein expression in a co culture model of liver and head kidney cells isolated from Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Holen, Elisabeth; He, Juyun; Araujo, Pedro; Seliussen, Jørgen; Espe, Marit

    2016-07-01

    Hydrolyzed fish proteins (H-pro) contain high concentrations of free amino acids and low molecular peptides that potentially may benefit fish health. The following study aimed to test whether the water-soluble phase of H-pro could attenuate lipopolysaccharide (LPS) provoked inflammation in liver cells and head kidney cells isolated from Atlantic salmon. Cells were grown as mono cultures or co cultures to assess possible crosstalk between immune cells and metabolic cells during treatments. Cells were added media with or without H-pro for 2 days before LPS exposure and harvested 24 h post LPS exposure. Respective cells without H-pro and LPS were used as controls. H-pro alone could affect expression of proteins directly as H-pro increased catalase protein expression in head kidney- and liver cells, regardless of culturing methods and LPS treatment. Leukotriene B4 (LTB4) production was also increased by H-pro in head kidney cells co cultured with liver cells. H-pro increased LPS induced interleukin 1β (IL-1β) transcription in liver cells co cultured with head kidney cells. All cultures of head kidney cells showed a significant increase in IL-1β transcription when treated with H-pro + LPS. H-pro decreased caspase-3 transcription in liver cells cultured co cultured with head kidney cells. Peroxisome proliferator activated receptor α (PPAR α) was upregulated, regardless of treatment, in liver cells co cultured with head kidney cells clearly showing that culturing method alone affected gene transcription. H-pro alone and together with LPS as an inflammation inducer, affect both antioxidant and inflammatory responses.

  9. Research on the tremor suppression test system for the tremor suppression robot%抑制震颤机器人抑震试验系统研究

    Institute of Scientific and Technical Information of China (English)

    李军强; 王娟; 高永生

    2012-01-01

    By applying the magnetorheological damper developed,a tremor suppression robot with 2 degree of freedom was designed,which tremor occurred in the process of elbow flexion or extension and forearm revolving can be suppressed.Then a tremor suppression controller was developed, which can execute (he tremor suppression control algorithm,convert and process the tremor information as well as output the control current and communical.e with the PC and so on.Finally the tremor system for simulating arm was designed,which can output tremor information for the tremor suppression tesuBased on above results, the motion control test for the tremor suppression test system was done., which result shows that the tremor suppression test system can simulate the tremor effectually.%应用所研制的磁流变阻尼器,设计了两个自由度的抑震机器人结构,可对人体上肢肘部屈/伸、前臂旋转运动过程中产生的震颤进行抑制.研制了抑震控制器,能够完成抑震控制算法的运行、震颤信息的转换与处理、控制量的输出以及与上位机通信等工作.设计了模拟人体上肢震颤系统,为抑震试验提供震颤信息.在此基础上进行了抑震试验系统运动控制试验,试验结果显示,所研制的抑震试验系统能够较好的模拟人体的震颤过程.

  10. Systematic search of triggered and ambient tectonic tremor in Southern California

    Science.gov (United States)

    Yang, H.; Peng, Z.

    2013-12-01

    Tectonic tremor has been extensively observed along the Parkfield-Cholame section of the San Andreas Fault in central California. In contrast, observations of either triggered or ambient tremor in southern California are quite sparse to date. In this study we conduct a systematic search of tectonic tremor around the Simi Valley (SV), the San Gabriel Mountain (SGM), and the San Jacinto Fault (SJF). We focus on these regions, mainly because of previous observations of triggered tremor at the SV and SJF, and evidence of near-lithostatic fluid under the SGM and deep creep along the SJF. We first search for tremor triggered by distant large earthquakes around the SV and the SGM in southern California. Out of 59 large earthquakes between 2000 and 2013, only the 2002 Mw 7.9 Denali Fault earthquake triggered clear tremor in the region. The observed travel times of the triggered tremors are consistent with theoretical predictions from tremor sources that are spatially clustered in the SV, close to the rupture zone of the 1994 Mw 6.7 Northridge earthquake. We also estimate the triggering stress threshold as ˜12 KPa from measuring the peak ground velocities near the tremor source. The lack of clear tremor beneath the SGM provides a 'negative' example for a region where tremor is expected to occur because of clear evidence of fluid-rich zones at the middle crust. The results imply that the necessary conditions for tremor to occur are more than fluid-induced low effective normal stress. In addition to tremor in the SV, we also investigate tremor along the SJF, where tremor was triggered by the 2002 Mw7.9 Denali Fault and the 2011 Mw9.1 Tohoku-Oki earthquakes. These triggered tremors provide natural templates of the low frequency earthquakes that can be used to perform matched-filter detection to search for additional tremors along the SJF. In addition, there are strain transients following the March 11, 2013, Mw 4.7 earthquake that are captured by PBO strainmeters near the SJF

  11. Contribution of inter-muscular synchronization in the modulation of tremor intensity in Parkinson's disease.

    Science.gov (United States)

    He, Xin; Hao, Man-Zhao; Wei, Ming; Xiao, Qin; Lan, Ning

    2015-12-01

    Involuntary central oscillations at single and double tremor frequencies drive the peripheral neuromechanical system of muscles and joints to cause tremor in Parkinson's disease (PD). The central signal of double tremor frequency was found to correlate more directly to individual muscle EMGs (Timmermann et al. 2003). This study is aimed at investigating what central components of oscillation contribute to inter-muscular synchronization in a group of upper extremity muscles during tremor in PD patients. 11 idiopathic, tremor dominant PD subjects participated in this study. Joint kinematics during tremor in the upper extremity was recorded along with EMGs of six upper arm muscles using a novel experimental apparatus. The apparatus provided support for the upper extremity on a horizontal surface with reduced friction, so that resting tremor in the arm can be recorded with a MotionMonitor II system. In each subject, the frequencies of rhythmic firings in upper arm muscles were determined using spectral analysis. Paired and pool-averaged coherence analyses of EMGs for the group of muscles were performed to correlate the level of inter-muscular synchronization to tremor amplitudes at shoulder and elbow. The phase shift between synchronized antagonistic muscle pairs was calculated to aid coherence analysis in the muscle pool. Recorded EMG revealed that rhythmic firings were present in most recorded muscles, which were either synchronized to form phase-locked bursting cycles at a subject specific frequency, or unsynchronized with a random phase distribution. Paired coherence showed a stronger synchronization among a subset of recorded arm muscles at tremor frequency than that at double tremor frequency. Furthermore, the number of synchronized muscles in the arm was positively correlated to tremor amplitudes at elbow and shoulder. Pool-averaged coherence at tremor frequency also showed a better correlation with the amplitude of resting tremor than that of double tremor

  12. Slip Updip of Tremor during the 2012 Cascadia ETS Event

    Science.gov (United States)

    Hall, K.; Houston, H.

    2014-12-01

    The interplay between tremor and slow slip during ETS has implications for the slip budget of the Cascadia subduction zone. In particular, it can constrain the downdip edge of the locked zone, which informs the hazard assessments for major cities including Seattle, Tacoma, and Vancouver. As shown by Houston (AGU abstract, 2012), slip inferred from GPS extended updip of the seismically-detected tremor in the 2010 M6.8 ETS event. Following the methods used on the 2010 ETS event, we used the PANGA GPS to measure the displacement vectors for 71 stations to analyze a large ETS event in 2012 that extended from Vancouver Island to Southern Washington. We implemented Principal Component Analysis to automatically select the direction and magnitude of the maximum displacement vector. We then inverted these GPS displacements for slip, using the Okada formulation of buried rectangular faults in a halfspace with a grid of 8 by 8 km subfaults based on the McCrory slab model. We performed inversions with either 0th or 2nd order Tikhonov regularization and found that over the 6 weeks of propagation, the 2012 ETS event released moment corresponding to M6.7, in three high-slip regions. We compared two different inversions, one where slip was allowed on a broad regional grid and a tremor-restricted inversion (TRI) where slip was restricted to grid locations where tremor had been detected in the 2012 ETS. We found that the TRI forced the slip to the updip edge of the grid where it reached above 10 cm, which is physically implausible given that this exceeds the slip that can accumulate in an inter-ETS time period. Additionally, the regional grid inversion indicates that 1 to 2 cm of slip occurred 10's of km updip of the western edge of tremor. This further supports the inference from the 2010 event that in northern Washington, the slow slip during an ETS event extends many kilometers updip of the western edge of tremor.

  13. Modulation of voice related to tremor and vibrato

    Science.gov (United States)

    Lester, Rosemary Anne

    Modulation of voice is a result of physiologic oscillation within one or more components of the vocal system including the breathing apparatus (i.e., pressure supply), the larynx (i.e. sound source), and the vocal tract (i.e., sound filter). These oscillations may be caused by pathological tremor associated with neurological disorders like essential tremor or by volitional production of vibrato in singers. Because the acoustical characteristics of voice modulation specific to each component of the vocal system and the effect of these characteristics on perception are not well-understood, it is difficult to assess individuals with vocal tremor and to determine the most effective interventions for reducing the perceptual severity of the disorder. The purpose of the present studies was to determine how the acoustical characteristics associated with laryngeal-based vocal tremor affect the perception of the magnitude of voice modulation, and to determine if adjustments could be made to the voice source and vocal tract filter to alter the acoustic output and reduce the perception of modulation. This research was carried out using both a computational model of speech production and trained singers producing vibrato to simulate laryngeal-based vocal tremor with different voice source characteristics (i.e., vocal fold length and degree of vocal fold adduction) and different vocal tract filter characteristics (i.e., vowel shapes). It was expected that, by making adjustments to the voice source and vocal tract filter that reduce the amplitude of the higher harmonics, the perception of magnitude of voice modulation would be reduced. The results of this study revealed that listeners' perception of the magnitude of modulation of voice was affected by the degree of vocal fold adduction and the vocal tract shape with the computational model, but only by the vocal quality (corresponding to the degree of vocal fold adduction) with the female singer. Based on regression analyses

  14. 19th-century American contributions to the recording of tremors.

    Science.gov (United States)

    Lanska, D J

    2000-07-01

    Studies of tremor in the 19th century were based initially on simple observation and later on the use of crude graphic recording devices that had been modified from instruments developed for other purposes. Like several European contemporaries, American investigators studying tremor used and adapted various existing instruments, including tambours and sphygmographs. A tambour used a drum-shaped pneumatic mechanism to transmit movements to a recording instrument, whereas the sphygmograph was a nonpneumatic mechanical device initially used to record the pulse. 19th-century American neurologists who used such devices included Frederick Peterson, Hobart Amory Hare, Charles Loomis Dana, and Augustus A. Eshner. Their measurements of tremor frequency were generally consistent with modern estimates for various types of tremor. Eshner, in particular, was frustrated by the overlap of frequency domains for tremors in different diseases, because this precluded use of tremor frequency alone as a differentiating feature for diagnosis. Peterson and Dana recognized the variation in tremor frequency in different body parts resulting from different natural resonance frequencies of these parts as a function of weight and elastic properties. Peterson, Dana, and Eshner also recognized that tremor amplitude and frequency are inversely related. Finally, these 19th-century investigators recognized that the tremor of Parkinson's disease is a relatively low-frequency rest tremor, suppressed by action, and generally synchronous in symmetric body parts, but varying in amplitude and frequency in different body parts or over time.

  15. One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

    Science.gov (United States)

    Dideriksen, Jakob L.; Gallego, Juan A.; Holobar, Ales; Rocon, Eduardo; Pons, Jose L.; Farina, Dario

    2015-08-01

    Objective. Pathological tremors are symptomatic to several neurological disorders that are difficult to differentiate and the way by which central oscillatory networks entrain tremorogenic contractions is unknown. We considered the alternative hypotheses that tremor arises from one oscillator (at the tremor frequency) or, as suggested by recent findings from the superimposition of two separate inputs (at the tremor frequency and twice that frequency). Approach. Assuming one central oscillatory network we estimated analytically the relative amplitude of the harmonics of the tremor frequency in the motor neuron output for different temporal behaviors of the oscillator. Next, we analyzed the bias in the relative harmonics amplitude introduced by superimposing oscillations at twice the tremor frequency. These findings were validated using experimental measurements of wrist angular velocity and surface electromyography (EMG) from 22 patients (11 essential tremor, 11 Parkinson’s disease). The ensemble motor unit action potential trains identified from the EMG represented the neural drive to the muscles. Main results. The analytical results showed that the relative power of the tremor harmonics in the analytical models of the neural drive was determined by the variability and duration of the tremor bursts and the presence of the second oscillator biased this power towards higher values. The experimental findings accurately matched the analytical model assuming one oscillator, indicating a negligible functional role of secondary oscillatory inputs. Furthermore, a significant difference in the relative power of harmonics in the neural drive was found across the patient groups, suggesting a diagnostic value of this measure (classification accuracy: 86%). This diagnostic power decreased substantially when estimated from limb acceleration or the EMG. Signficance. The results indicate that the neural drive in pathological tremor is compatible with one central network

  16. Tremor and hand-arm vibration syndrome (HAVS) in road maintenance workers.

    Science.gov (United States)

    Bast-Pettersen, Rita; Ulvestad, Bente; Færden, Karl; Clemm, Thomas Aleksander C; Olsen, Raymond; Ellingsen, Dag Gunnar; Nordby, Karl-Christian

    2017-01-01

    The aim of this study was to evaluate postural and rest tremor among workers using vibrating hand tools, taking into account the possible effects of toxicants such as alcohol and tobacco. A further aim was to study workers diagnosed with hand-arm vibration syndrome (HAVS) at the time of examination. This study comprises 103 road maintenance workers, 55 exposed to vibrating hand tools (age 41.0 years; range 21-62) and 48 referents (age 38.5 years; range 19-64). They were examined with the CATSYS Tremor Pen(®). Exposure to vibrating tools and serum biomarkers of alcohol and tobacco consumption were measured. Cumulative exposure to vibrating tools was associated with increased postural (p < 0.01) and rest tremor (p < 0.05) and with a higher Center Frequency of postural tremor (p < 0.01) among smokers and users of smokeless tobacco. Rest tremor Center Frequency was higher than postural tremor frequency (p < 0.001). The main findings indicate an association between cumulative exposure to hand-held vibrating tools, tremor parameters and consumption of tobacco products. The hand position is important when testing for tremor. Rest tremor had a higher Center Frequency. Postural tremor was more strongly associated with exposure than rest tremor. The finding of increased tremor among the HAVS subjects indicated that tremor might be a part of the clinical picture of a HAVS diagnosis. As with all cross-sectional studies, inferences should be made with caution when drawing conclusions about associations between exposure and possible effects. Future research using longitudinal design is required to validate the findings of the present study.

  17. Systematic Search of Remotely Triggered Tremor in Northern and Southern California

    Science.gov (United States)

    Fabian, A.; Ojha, L.; Peng, Z.; Chao, K.

    2009-12-01

    Non-volcanic tremor is a seismic signal observed away from volcanoes, and is characterized with long durations and no clear body wave arrivals. Recent studies have found that non-volcanic tremor can be triggered instantaneously during the surface waves of large teleseismic events in Central California, Japan, Cascadia, and Taiwan. However, it is still not clear how widespread the triggering phenomenon is, and what are the necessary conditions for tremor to occur. Here we conduct a systematic search of remotely triggered tremor in Northern and Southern California, focusing on the following regions with dense instrumentations: the Central Calaveras fault, the Northern Hayward fault, the San Jacinto fault near Hemet and the Simi Valley, and the San Gabriel Mountains. Out of the 30 large teleseismic events with Mw ≥ 7.5 since 2001, our visual inspection shows that only the 2002 Mw7.8 Denali Fault earthquake has triggered tremor in these regions, including the San Gabriel Mountains where neither triggered nor ambient tremor has been observed before. The tremor observed near the Calaveras fault and San Jacinto fault appears to be initiated by Love waves, and becomes intensified during the large amplitude Rayleigh waves. The tremor triggered in Simi Valley and San Gabriel Mountains only shows weak correlations with the Rayleigh waves. Our results suggest a lack of widespread triggering in Northern and Southern California, which is in contrast with the finding of multiple events that triggered tremor in Central California, Japan, Cascadia, and Taiwan. However, such observation is consistent with a general lack of ambient tremor activities in these regions. Possible reasons for a lack of widespread triggering in Northern and Southern California include: elevated background noises for surface stations that may hide weak triggered tremor signals, different ambient tremor rate, or different tremor triggering threshold in different regions. Updated results will be presented

  18. The long head of biceps as a source of pain in active population: tenotomy or tenodesis? A comparison of 2 case series with isolated lesions.

    Science.gov (United States)

    Delle Rose, Giacomo; Borroni, Mario; Silvestro, Alessandro; Garofalo, Raffaele; Conti, Marco; De Nittis, Pasquale; Castagna, Alessandro

    2012-05-01

    The tendon of the long head of the biceps (LHB) is a common source of pain in the shoulder, and the surgical treatments proposed are tenotomy or tenodesis performed in different ways. The purpose of this study is to compare the clinical results (objective and subjective) of tenotomy versus soft tissue tenodesis. One-hundred and four patients with an isolated LHB pathology, arthroscopically treated between 2004 and 2007, were observed retrospectively. Forty-eight of these patients were treated with tenotomy and 56 with a soft tissue tenodesis technique. All the patients were evaluated by an independent observer with a minimum follow-up of 2 years which included VAS, DASH questionnaire, Constant score and ROM evaluation with a goniometer. All these evaluations were performed pre- and post-operatively. An independent expert radiologist then performed an ultrasound examination only in the post-operative evaluation of the tenodesis group looking to confirm the effectiveness of the procedure. In both groups, the scores were significantly improved. In the tenotomy group, 16.6 % of the patients had bicipital cramps for a mean post-operative time of 1 month. Constant score improved in both groups: 46.6 to 86.1 in tenotomy group and 48.9-84.9 in tenodesis group; VAS improved from 8.4 to 1.5 in tenotomy group and from 8.8 to 1.4 in tenodesis group; DASH scores changed from 42.5 to 13.6 in tenotomy group and from 55.8 to 11.4 in tenodesis group. Popeye sign was present in 37.5 % in the tenotomy group and in 5.3 % in tenodesis group. In 3 patients of the tenodesis group, ultrasound revealed complete failure of the tenodesis. In conclusion, both procedures are effective in terms of treatment of LHB pathologies. Tenotomy does not require specific post-operative treatment and is easy to perform, but cramp and Popeye sign may occur after surgery. The soft tissue tenodesis technique is an easy and cost-effective way to perform tenodesis with good results, especially in preventing

  19. Neural networks and dynamical system techniques for volcanic tremor analysis

    Directory of Open Access Journals (Sweden)

    R. Carniel

    1996-06-01

    Full Text Available A volcano can be seen as a dynamical system, the number of state variables being its dimension N. The state is usually confined on a manifold with a lower dimension f, manifold which is characteristic of a persistent «structural configuration». A change in this manifold may be a hint that something is happening to the dynamics of the volcano, possibly leading to a paroxysmal phase. In this work the original state space of the volcano dynamical system is substituted by a pseudo state space reconstructed by the method of time-delayed coordinates, with suitably chosen lag time and embedding dimension, from experimental time series of seismic activity, i.e. volcanic tremor recorded at Stromboli volcano. The monitoring is done by a neural network which first learns the dynamics of the persistent tremor and then tries to detect structural changes in its behaviour.

  20. A double-correlation tremor-location method

    CERN Document Server

    Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Gudmundsson, Ólafur

    2016-01-01

    A double-correlation method is introduced to locate tremor sources based on stacks of complex, doubly-correlated tremor records of multiple triplets of seismographs back projected to hypothetical source locations in a geographic grid. Peaks in the resulting stack of moduli are inferred source locations. The stack of the moduli is a robust measure of energy radiated from a point source or point sources even when the velocity information is imprecise. Application to real data shows how double correlation focuses the source mapping compared to the common single correlation approach. Synthetic tests demonstrate the robustness of the method and its resolution limitations which are controlled by the station geometry, the finite frequency of the signal, the quality of the used velocity information and noise level. Both random noise and signal or noise correlated at time shifts that are inconsistent with the assumed velocity structure can be effectively suppressed. Assuming a surface-wave velocity, we can constrain t...

  1. Regular and stochastic behavior of Parkinsonian pathological tremor signals

    CERN Document Server

    Yulmetyev, R M; Panischev, O Y; Hänggi, P; Timashev, S F; Vstovsky, G V; Yulmetyev, Renat M.; Demin, Sergey A.; Panischev, Oleg Yu.; H\\"anggi, Peter; Timashev, Serge F.; Vstovsky, Grigoriy V.

    2006-01-01

    Regular and stochastic behavior in the time series of Parkinsonian pathological tremor velocity is studied on the basis of the statistical theory of discrete non-Markov stochastic processes and flicker-noise spectroscopy. We have developed a new method of analyzing and diagnosing Parkinson's disease (PD) by taking into consideration discreteness, fluctuations, long- and short-range correlations, regular and stochastic behavior, Markov and non-Markov effects and dynamic alternation of relaxation modes in the initial time signals. The spectrum of the statistical non-Markovity parameter reflects Markovity and non-Markovity in the initial time series of tremor. The relaxation and kinetic parameters used in the method allow us to estimate the relaxation scales of diverse scenarios of the time signals produced by the patient in various dynamic states. The local time behavior of the initial time correlation function and the first point of the non-Markovity parameter give detailed information about the variation of p...

  2. Long-distance induced tremor observed off western Canada

    Science.gov (United States)

    Schultz, Colin

    2013-05-01

    Using seismic observations made near the Queen Charlotte Margin (QCM), a seismically active region off the western coast of Canada, Aiken et al. add to the growing body of research on how large earthquakes can cause tectonic plates to slip half way around the world. Reaching north from the intersection of the Juan de Fuca ridge, the Cascadia subduction zone, and the Queen Charlotte Fault, QCM underlies the islands of Haida Gwaii and was the site of a magnitude 7.7 earthquake in October 2012. Drawing on seismic readings collected from 1990 to 2012 and using a database of major worldwide earthquakes, the authors identified three earthquakes that induced tremors in QCM: the 2002 magnitude 7.9 Denali earthquake, the 2004 magnitude 9.2 Sumatra quake, and the 2011 magnitude 9.1 Tohoku earthquake. The authors observed the induction not of conventional earthquakes but of deep tectonic tremors, slips of tectonic plates with epicenters located far beneath the surface.

  3. Botulinum Toxin for the Treatment of Tremor and Tics.

    Science.gov (United States)

    Lotia, Mitesh; Jankovic, Joseph

    2016-02-01

    The therapeutic applications of botulinum toxin (BoNT) have grown manifold since its initial approval in 1989 by the U.S. Food and Drug Administration for the treatment of strabismus, blepharospasm, and other facial spasms. Although it is the most potent biologic toxin known to man, long-term studies have established its safety in the treatment of a variety of neurologic and nonneurologic disorders. Despite a paucity of randomized controlled trials, BoNT has been found to be beneficial in treating a variety of tremors and tics when used by clinicians skilled in the administration of the drug for these hyperkinetic movement disorders. Botulinum toxin injections can provide meaningful improvement in patients with localized tremors and tics; in some cases, they may be an alternative to other treatments with more undesirable adverse effects.

  4. Ambient Tremor Triggered by Long-term Slow Slip Event in Bungo Channel, Southwest Japan

    Science.gov (United States)

    Obara, K.; Hirose, H.; Matsuzawa, T.; Tanaka, S.; Maeda, T.

    2014-12-01

    Episodic tremor and slip (ETS) is a stick-slip in the transition zone between locked and stable sliding zones on the plate interface in Southwest Japan and Cascadia. ETS episode with duration of several days usually recurs at interval of several months at each segment. On the other hand, in the Bungo channel region where is the western edge of the ETS zone in SW Japan, tremor activity continued for several months during the long-term slow slip event (SSE) in 2003 and 2010. In this paper, the relationship between long-term SSE and surrounded triggered tremor is discussed. Tremor triggered by the long-term SSE is spatially localized in the narrow width of about 10 km at the shallowest part of the tremor zone, and at the neighboring area just downdip from the source fault of the SSE. The frequency distribution of tremor along the dip direction during the SSE period is consistent with the spatial distribution of total slip estimated for 2010 SSE. Therefore, the slip of the long-term SSE penetrated in the ETS zone may generate tremor. The daily number of the activated tremor is 12-14 during the SSE; however, it is 40-50 for regular ETS episode during the inter-SSE period. On the other hand, slip rates of the long-term SSE and ETS are typically 1 mm/d and 3 mm/d, respectively. Therefore, tremor rate may be controlled by slip rate. After SSEs in 2003 and 2010, tremor activity seems to slightly increase in the east region within 50 km from the triggered tremor area. Such 7-year period variation in tremor activity is observed in only the shallower side of the tremor zone. Moreover, pattern of the long-term variation seems to slightly migrate to east during a few years. We interpret that a tiny transient slip after the long-term SSE slowly propagates between transition and locked zones. Tremor activity at the shallowest part of the tremor zone in the Bungo channel continued longer than that of regular ETS in the late 2006 during the inter-SSE period. Associated tiny GPS

  5. Joint observation of long period tremor signals with broadband seismometer, tiltmeter and gravimeter

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-bin; JIANG Jun; LIAO Ying-chun; LI Sheng-le; ZHONG Tie-tao

    2008-01-01

    We report here the observation result of joint observation of long period tremor signals with broadband seismometer, tiltmeter and gravimeter at the HUST (Huazhong University of Science and Technology) station. The observed data were compared and analyzed. Since 2005, the several tens of abnormal tremor signals which are weak, complex and duration of 2 to 3 days have been synchronously recorded by the different instruments. The tremor signals have the periodic domain in the range of 3 to 5 minutes, 20 to 30 minutes and even more than 1 hour. The observation shows such tremors are a physical existence. The analysis indicates that a part of the tremors caused by the typhoon from the western Pacific Ocean. These tremors have a close relationship with wind velocity of typhoon and distance between the typhoon center and the station. Except these, the cause of others is still unclear.

  6. Electrophysiologic Assessments of Involuntary Movements: Tremor and Myoclonus

    Directory of Open Access Journals (Sweden)

    Hyun-Dong Park

    2009-05-01

    Full Text Available Tremor is defined as a rhythmical, involuntary oscillatory movement of a body part. Although neurological examination reveals information regarding its frequency, regularity, amplitude, and activation conditions, the electrophysiological investigations help in confirming the tremor, in differentiating it from other hyperkinetic disorders like myoclonus, and may provide etiological clues. Accelerometer with surface electromyogram (EMG can be used to document the dominant frequency of a tremor, which may be useful as certain frequencies are more characteristic of specific etiologies than others hyperkinetic disorders. It may show rhythmic bursts, duration and activation pattern (alternating or synchronous. Myoclonus is a quick, involuntary movement. Electrophysiological studies may helpful in the evaluation of myoclonus, not only for confirming the clinical diagnosis but also for understanding the underlying physiological mechanisms. Electroencephalogram (EEG-EMG correlates can give us important information about myoclonus. Jerk-locked back-averaging and evoked potentials with recording of the long-latency, long-loop reflexes are currently available to study the pathophysiology of myoclonus.

  7. Volcanic tremor associated with eruptive activity at Bromo volcano

    Directory of Open Access Journals (Sweden)

    E. Gottschämmer

    1999-06-01

    Full Text Available Three broadband stations were deployed on Bromo volcano, Indonesia, from September to December 1995. The analysis of the seismograms shows that the signals produced by the volcanic sources cover the frequency range from at least 25 Hz down to periods of several minutes and underlines, therefore, the importance of broadband recordings. Frequency analysis reveals that the signal can be divided into four domains. In the traditional frequency range of volcanic tremor (1-10 Hz sharp transitions between two distinct values of the tremor amplitude can be observed. Additional tremor signal including frequencies from 10 to 20 Hz could be found during late November and early December. Throughout the whole experiment signals with periods of some hundred seconds were observed which are interpreted as ground tilts. For these long-period signals a particle motion analysis was performed in order to estimate the source location. Depth and radius can be estimated when the source is modeled as a sudden pressure change in a sphere. The fourth frequency range lies between 0.1 and 1 Hz and is dominated by two spectral peaks which are due to marine microseism. The phase velocity and the direction of wave propagation of these signals could be determined using the tripartite-method.

  8. Nonvolcanic tremor observed in the Mexican subduction zone

    Science.gov (United States)

    Payero, Juan S.; Kostoglodov, Vladimir; Shapiro, Nikolai; Mikumo, Takeshi; Iglesias, Arturo; Pérez-Campos, Xyoli; Clayton, Robert W.

    2008-04-01

    Nonvolcanic tremor (NVT) activity is revealed as episodes of higher spectral amplitude at 1-8 Hz in daily spectrograms from the continuous seismological records in Guerrero, Mexico. The analyzed data cover a period of 2001-2007 when in 2001-2002 a large slow slip event (SSE) had occurred in the Guerrero-Oaxaca region, and then a new large SSE occurred in 2006. The tremor burst is dominated by S-waves. More than 100 strong NVT bursts were recorded in the narrow band of ~40 × 150 km2 to the south of Iguala City and parallel to the coastline. Depths of NVT hypocenters are mostly scattered in the continental crust between 5 and 40 km depth. Tremor activity is higher during the 2001-2002 and 2006 SSE compared with that for the ``quiet'' period of 2003-2005. While resistivity pattern in Guerrero does not correlate directly with the NVT distribution, gravity and magnetic anomaly modeling favors a hypothesis that the NVT is apparently related to the dehydration and serpentinization processes.

  9. Prenatal exposure to the organophosphate pesticide chlorpyrifos and childhood tremor

    Science.gov (United States)

    Rauh, Virginia A.; Garcia, Wanda E.; Whyatt, Robin M.; Horton, Megan K.; Barr, Dana B.; Louis, Elan D.

    2016-01-01

    Background The organophosphate insecticide chlorpyrifos (CPF), widely used for agricultural purposes, has been linked to neurodevelopmental deficits. Possible motor effects at low to moderate levels of exposure have not been evaluated. Methods Prenatal exposure to CPF was measured in umbilical cord blood in a sample of 263 inner-city minority children, who were followed prospectively. At approximately 11 years of age (mean age 10.9 ± 0.85 years, range = 9.0–13.9), during a neuropsychological assessment, children were asked to draw Archimedes spirals. These were rated by a senior neurologist specializing in movement disorders who was blind to CPF exposure level. Results Compared to all other children, those with prenatal CPF exposure in the upper quartile range (n = 43) were more likely to exhibit mild or mild to moderate tremor (≥1) in either arm (p = 0.03), both arms (p = 0.02), the dominant arm (p = 0.01), and the non-dominant arm (p = 0.055). Logistic regression analyses showed significant CPF effects on tremor in both arms, either arm, the dominant arm (p-values < 0.05), and the non-dominant arm (p = 0.06), after adjustment for sex, age at testing, ethnicity, and medication. Conclusion Prenatal CPF exposure is associated with tremor in middle childhood, which may be a sign of the insecticide's effects on nervous system function. PMID:26385760

  10. Orthostatic tremor: Report of a case and review of the literature

    Directory of Open Access Journals (Sweden)

    Bhattacharyya K

    2003-01-01

    Full Text Available Orthostatic tremor is a rare movement disorder characterized by tremulousness of the lower limbs on standing that disappears on walking, sitting or on lying down and a distinctive electromyographic burst of 14 to 16 Hz. On inspection, fine ripples can sometimes be seen over the quadriceps on standing. The tremor has a tendency to reappear even in the supine posture if the lower limb muscles are put to an isometric contraction state, indicating thereby that in spite of the fact that the tremor occurs on standing, it is essentially 'orthostasis independent' and the central factor is the contraction of the muscles. As a matter of fact, the tremor is abolished if the subject is suspended by harness, thus relieving him of muscle contraction. Doubts are being cast whether it is a variant of essential tremor since a number of families are being reported to be suffering from this disease as well. Positron emission tomography reveals hyperactivity of cerebellum in orthostatic tremor as it shows in essential tremor, therefore lending credence to such a hypothesis. However, lack of response to alcohol, propranolol and primidone in orthostatic tremor stands out as a serious challenge to such a view. Lack of positive family history, synchrony of contracting group of muscles and negative `reseting' of the tremor by increasing peripheral load-phenomena consistently observed in orthostatic tremor and not in essential tremor, are other features that often help to distinguish between the two conditions. We report a case of orthostatic tremor that presented with the classical clinical and eletromyographic features. Relevant literature in this regard is also being reviewed.

  11. Tremor, hypermyotonia and gatism%震颤肌张力增高大小便失禁

    Institute of Scientific and Technical Information of China (English)

    陈立云; 张国平; 贺茂林

    2013-01-01

    Neuropsychiatric systemic lupus erythematosus (NP-SLE) is more common in young woman but not yet in people over 75 years old.We report a case of NP-SLE in an old woman,who complained of tremor,hypermyotonia and gatism.The lab examinations showed strong positive (1∶3200) ANA,decreased levels of CH50,C3,C4,WBC,RBC,PLT,anti-ds-DNA(+),anti-Sm(+),SSA(+),PO(+),RO-52(+),urine blood (+) and protein (+).The proteins,MBPand IgGin CSF were increased.Head MRI scan showed many demyelination in bilateral intra ventricular and multiple patchy irregular long T1 and T2 signal under right parietal subcortical.The patient was immediately given methylprednisolone hormone therapy,combined with gamma globulin and hydroxychloroquine.After 4 days of treatment,most symptoms such as tremor and hypermyotonia disappeared.Laboratory tests showed that all immune markers changed better in three weeks.The patient was discharged in 4 weeks.it must be identified with cerebrovascular disease,Parkinson's disease and other common diseases in elderly people.It can be improved if the diagnosis and treatment of NP-SLE is immediately and the illness is well controlled.

  12. Seismic Tremors and Three-Dimensional Magma Wagging

    Science.gov (United States)

    Liao, Y.; Bercovici, D.

    2015-12-01

    Seismic tremor is a feature shared by many silicic volcanoes and is a precursor of volcanic eruption. Many of the characteristics of tremors, including their frequency band from 0.5 Hz to 7 Hz, are common for volcanoes with very different geophysical and geochemical properties. The ubiquitous characteristics of tremor imply that it results from some generation mechanism that is common to all volcanoes, instead of being unique to each volcano. Here we present new analysis on the magma-wagging mechanism that has been proposed to generate tremor. The model is based on the suggestion given by previous work (Jellinek & Bercovici 2011; Bercovici et.al. 2013) that the magma column is surrounded by a compressible, bubble-rich foam annulus while rising inside the volcanic conduit, and that the lateral oscillation of the magma inside the annulus causes observable tremor. Unlike the previous two-dimensional wagging model where the displacement of the magma column is restricted to one vertical plane, the three-dimensional model we employ allows the magma column to bend in different directions and has angular motion as well. Our preliminary results show that, without damping from viscous deformation of the magma column, the system retains angular momentum and develops elliptical motion (i.e., the horizontal displacement traces an ellipse). In this ''inviscid'' limit, the magma column can also develop instabilities with higher frequencies than what is found in the original two-dimensional model. Lateral motion can also be out of phase for various depths in the magma column leading to a coiled wagging motion. For the viscous-magma model, we predict a similar damping rate for the uncoiled magma column as in the two-dimensional model, and faster damping for the coiled magma column. The higher damping thus requires the existence of a forcing mechanism to sustain the oscillation, for example the gas-driven Bernoulli effect proposed by Bercovici et al (2013). Finally, using our new 3

  13. Cross-spectral analysis of physiological tremor and muscle activity; 2, Application to synchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between synchronized muscle activity and tremor time series in (enhanced) physiological tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and its possibilities to clarify the contribution of reflex mechanisms to physiological tremor. The phase spectra are investigated under the assumptions that the EMG synchronization was caused by a reflex, respectively a central oscillator. In comparison of these results to phase spectra of measured data we found a significant contribution of reflexes. But reflexes only modify existing peaks in the power spectrum. The main agents of physiological tremor are an efferent pace and the resonant behavior of the biomechanical system.

  14. Observations of two special kinds of tremor at Galeras volcano, Colombia(1989-1991

    Directory of Open Access Journals (Sweden)

    F. Gil-Cruz

    1999-06-01

    Full Text Available Since the reactivation of Galeras volcano in 1988 its seismic activity has been dominated by a variety of LP waveforms and tremor events. Some of these signals occurred as a response to volcanic activity. Among them, two kinds of tremor deserve special attention, Flute tremor and Spasmodic tremor. Flute tremor has a spectrum of equally spaced peaks and is associated with a quasi-steady degassing process at the top of the lava dome. It is accompanied by a flute-like sound. Its spectral features and the correlation with field observations are consistent with a model generation indicating that a crack or set of cracks are excited to resonance by the release and flow of gas through the lava dome. Spasmodic tremor is composed of several distinct LP-like events joined together by a continuous signal with lower amplitudes. Two types of spasmodic tremor may be distinguished on the basis of their spectral characteristics and field observations. Spasmodic tremor type I is apparently dominated by a mix of P, SH and Rayleigh waves as determined from preliminary polarization analysis. The source appears to be located, in a region west of the active crater. As a first approximation, Spasmodic tremor type I could be associated with magmatic intrusion process occurred in 1989-1991.

  15. Primary task-specific bowing tremor: an entity of its own?

    Science.gov (United States)

    Lee, André; Altenmüller, Eckart

    2012-12-01

    A professional violinist in his early 60s, playing in a prestigious German orchestra for more than 20 years, presented to our institute because of a task-induced tremor in his right arm when playing the violin. We describe the phenomenology of this tremor and its treatment options and compare it to findings in primary writing tremor (PWT). We then discuss whether primary bowing tremor is an entity of its own (similar to PWT) and propose hypotheses that would derive from such a definition.

  16. Essential tremor then and now: How views of the most common tremor diathesis have changed over time.

    Science.gov (United States)

    Louis, Elan D

    2017-07-13

    Essential tremor (ET) is the most prevalent tremor diathesis. In this "then" and "now" piece, I detail how views of this disorder have changed over time. A PubMed search was conducted on June 15, 2017. The term "essential tremor" was crossed in sequential order with 14 s search terms (e.g., genetics, clinical). The traditional view of ET was that it was monosymptomatic. An emerging view of ET is as a more clinically-complex entity with a range of possible motor and non-motor features. Traditionally, ET was viewed as autosomal dominant with complete penetrance by age 65. Current thinking is that, in addition to monogenic forms of ET, the disease is likely to be complex, with incomplete penetrance into advanced age. While non-genetic factors were traditionally presumed to exist, epidemiological studies have explored several potential environmental toxicants. The traditional olivary model of ET posited the existence of a central oscillator; an alternative is the cerebellar degenerative model, which is now under consideration. For ET, there is clearly a "then" and "now" when one assesses changes in our understanding of the disease with time. Indeed, concepts relating to the clinical features, disease etiology and pathogenesis have all changed substantially. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Fragile X-associated tremor/ataxia syndrome: An under-recognised cause of tremor and ataxia.

    Science.gov (United States)

    Kalus, Sarah; King, John; Lui, Elaine; Gaillard, Frank

    2016-01-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive degenerative movement disorder resulting from a fragile X "premutation", defined as 55-200 CGG repeats in the 5'-untranslated region of the FMR1 gene. The FMR1 premutation occurs in 1/800 males and 1/250 females, with FXTAS affecting 40-45% of male and 8-16% of female premutation carriers over the age of 50. FXTAS typically presents with kinetic tremor and cerebellar ataxia. FXTAS has a classical imaging profile which, in concert with clinical manifestations and genetic testing, participates vitally in its diagnosis. The revised FXTAS diagnostic criteria include two major radiological features. The "MCP sign", referring to T2 hyperintensity in the middle cerebellar peduncle, has long been considered the radiological hallmark of FXTAS. Recently included as a major radiological criterion in the diagnosis of FXTAS is T2 hyperintensity in the splenium of the corpus callosum. Other imaging features of FXTAS include T2 hyperintensities in the pons, insula and periventricular white matter as well as generalised brain and cerebellar atrophy. FXTAS is an under-recognised and misdiagnosed entity. In patients with unexplained tremor, ataxia and cognitive decline, the presence of middle cerebellar peduncle and/or corpus callosum splenium hyperintensity should raise suspicion of FXTAS. Diagnosis of FXTAS has important implications not only for the patient but also, through genetic counselling and testing, for future generations.

  18. A Global Review of Slow Slip Events and Seismic Tremor at Circum-Pacific Subduction Zones

    Science.gov (United States)

    Schwartz, S. Y.; Rokosky, J. M.

    2006-12-01

    It has been known for a long time that slip accompanying earthquakes accounts for only a fraction of plate tectonic displacements. However, only recently has a fuller spectrum of strain release processes, including normal, slow and silent earthquakes (or slow slip events), and continuous and episodic creep, been observed and generated by numerical simulations of the earthquake cycle. Despite a profusion of observations and modeling studies, the physical mechanism of slow slip events (SSEs) remains elusive. The concurrence of seismic tremor, similar to signals observed at volcanoes, with slow slip episodes in Cascadia and southwestern Japan suggests that SSEs may be related to fluid migration on or near the plate interface. We compare the location, spatial extent, magnitude, duration, slip rate, recurrence behavior and associated tremor and seismicity of aseismic slip transients worldwide to better understand their generation and earthquake hazard implications. We find that slow slip events occur at either the down-dip edge of the seismogenic zone, or at complementary locations to strongly locked patches or co-seismic asperities within the seismogenic zone. Nucleation of SSEs at frictional transitions is supported by rate- and state-dependent frictional modeling. We find a global scaling relationship between SSE duration and equivalent moment magnitude that implies a constant rate of slow slip propagation, consistent with the small range in observed SSE migration rates. Afterslip following moderate to large earthquakes suggests a relationship between slow slip and higher velocity rupture (earthquakes). We assess if such a cause-and-effect relationship exists between interseismic SSEs and earthquake activity. We find that although isolated episodes of interseismic slow slip can be related to nearby earthquake activity, a consistent triggering pattern has yet to emerge and further study is clearly warranted.

  19. Inhibition of p38 MAPK during cellular activation modulate gene expression of head kidney leukocytes isolated from Atlantic salmon (Salmo salar) fed soy bean oil or fish oil based diets.

    Science.gov (United States)

    Holen, E; Winterthun, S; Du, Z-Y; Krøvel, A V

    2011-01-01

    Head kidney leukocytes isolated from Atlantic salmon fed either a diet based on fish oil (FO) or soy bean oil (VO) were used in order to evaluate if different lipid sources could contribute to cellular activation of the salmon innate immune system. A specific inhibitor of p38 MAPK, SB202190, was used to investigate the effect of lipopolysaccharide (LPS) signalling in the head kidney leukocytes. The results show that LPS up regulate IL-1β, TNF-α, Cox2 expression in leukocytes isolated from fish fed either diet. The p38 MAPK inhibitor, SB202190, reduced the LPS induced expression of these genes in both dietary groups. In LPS stimulated leukocytes isolated from VO fed fish, SB202190 showed a clear dose dependent inhibitory effect on IL-1β, TNF-α and Cox2 expression. This effect was also observed for Cox2 in leukocytes isolated from FO fed fish. Furthermore, there was a stronger mean induction of Cox2 in LPS stimulated leucocytes isolated from the VO-group compared to LPS stimulated leukocytes isolated from the FO-group. In both dietary groups, LPS stimulation of salmon head kidney leukocytes increased the induction of CD83, a dendrite cell marker, while the inhibitor reduced CD83 expression in the VO fed fish only. The inhibitor also clearly reduced hsp27 expression in VO fed fish. Indicating a p38 MAPK feedback loop, LPS significantly inhibited the expression of p38MAPK itself in both diets, while SB202190 increased p38MAPK expression especially in the VO diet group. hsp70 expression was not affected by any treatment or feed composition. There were also differences in p38MAPK protein phosphorylation comparing treatment groups but no obvious difference comparing the two dietary groups. The results indicate that dietary fatty acids have the ability to modify signalling through p38 MAPK which may have consequences for the fish's ability to handle infections and stress. Signalling through p38MAPK is ligand dependent and affects gene and protein expression differently.

  20. Detecting tectonic tremor through frequency scanning at a single station: Application to the Cascadia margin

    Science.gov (United States)

    Sit, Stefany; Brudzinski, Michael; Kao, Honn

    2012-11-01

    The discovery of episodic tremor and slip (ETS) spurred increased instrumentation and investigation of the Cascadia margin, which is now typified by the seismic phenomena. We utilize established detection and location techniques already present in the region to guide the development of a new single station detection method. While detailed network-wide investigations have led to exciting discoveries on the source location and migration patterns of tectonic tremor, single station detection has the ability to expand our search for tremor to more subduction zones and tectonic settings where instrumentation is not widely available. Our frequency scanning technique bandpass filters seismic data into three categories, 2-5 Hz, 10-15 Hz, and 0.02-0.1 Hz, where we expect prominent signals produced by tectonic tremor, local earthquakes, and surface waves, respectively. We combine amplitudes in each category into a ratio to determine tremor detection for a given hour. Results from our technique are evaluated in two ways: 1) combined in a network setting to compare with prominent location and detection methods and 2) assessed at an individual station and compared with other techniques that are capable of single station tremor detection. Network-wide processing over a two-year time period in both northern and southern Cascadia reveals common identification of larger ETS episodes when comparing our technique to both envelope waveform and combined single station detection methods. We find slight variations in the total duration of tremor and the onset timing between the different techniques, which may be due to the varying stations included in each technique. Frequency scanning identifies more inter-ETS episodes than envelope waveform and single station methods, particularly in the more sparsely instrumented region of southern Oregon. Our method also reduces erroneous signals more commonly found in other single station methods, discerned through comparison of nearby seismograms

  1. Assessing the Updip Spatial Offset of Tremor and Slip during ETS Events in Cascadia

    Science.gov (United States)

    Krogstad, R. D.; Schmidt, D. A.

    2015-12-01

    We investigate the updip spatial overlap of tremor and slip during recent episodic tremor and slip (ETS) events in Cascadia using a combination of forward and inverse models constrained by GPS, strainmeter, and tremor observations. Results from major ETS events in northern Cascadia suggest that, although there is significant spatial overlap, slow slip tends to extend further updip than tremor. ETS activity is thought to be dependent on a range of parameters, such as variable fluid pressures, temperature dependent physical properties, and facies changes. A spatial offset would indicant that tremor and slip are reflective of different physical conditions. While a clear offset of tremor and slip has been observed in multiple other subduction zones, a similar offset in Cascadia has remained difficult to constrain. Here we seek to establish whether the updip spatial offset is real in Cascadia and to quantify its extent. To complement GPS observations in Cascadia, we incorporate high fidelity strainmeter observations into inversions and sensitivity tests of iterative forward models. Tremor distributions are used as a proxy for slip and incorporated into slip models where parameters affecting the distribution and magnitude of slip are allowed to vary. These slip models are used to forward predict surface displacements and strains, which are then compared to the geodetic observations and inferred slip based on geodetic inversions. Results indicate that, while the tremor-derived slip distributions do a good job predicting the broad-scale surface deformation, the best-fit models have slip updip of the peak tremor activity. The fine-scale relationship of tremor and slip appears to vary on an event-by-event basis, where areas of high tremor density do not always correlate with increased surface displacements and vice-versa.

  2. In Vitro Susceptibility of Clinical Isolates of Aspergillus spp. to Anidulafungin, Caspofungin, and Micafungin: a Head-to-Head Comparison Using the CLSI M38-A2 Broth Microdilution Method▿

    Science.gov (United States)

    Pfaller, M. A.; Boyken, L.; Hollis, R. J.; Kroeger, J.; Messer, S. A.; Tendolkar, S.; Diekema, D. J.

    2009-01-01

    We determined the in vitro activities of anidulafungin, caspofungin, and micafungin against 526 isolates of Aspergillus spp. (64 A. flavus, 391 A. fumigatus, 46 A. niger, and 25 A. terreus isolates) collected from over 60 centers worldwide from 2001 through 2007. Susceptibility testing was performed according to the CLSI M38-A2 method. All three echinocandins—anidulafungin (50% minimum effective concentration [MEC50], 0.007 μg/ml; MEC90, 0.015 μg/ml), caspofungin (MEC50, 0.015 μg/ml; MEC90, 0.03 μg/ml), and micafungin (MEC50, 0.007 μg/ml; MEC90, 0.015 μg/ml)—were very active against Aspergillus spp. More than 99% of all isolates were inhibited by ≤0.06 μg/ml of all three agents. PMID:19710267

  3. Episodic tremor and slip - a kinder and gentler variety of earthquake

    Science.gov (United States)

    Vidale, J. E.; Peng, Z.; Creager, K. C.

    2008-12-01

    Episodic Tremor and Slip (AKA ETS) is appearing numerous unsuspected places as seismic instruments and analysis gears up into the 21st century. From its initial and loudest lair in subduction zones, ETS observations have spread to strike-slip faults and fold-thrust belts. ETS differs from old-school earthquakes. ETS can last weeks while the grandest earthquakes run out of steam in minutes. ETS unleashes seismic moment roughly linearly with duration, as opposed to run-of-the- mill earthquakes, whose moment scales with the cube of duration. ETS has a redder spectrum and more emergent beginnings. ETS is more sensitive to stress perturbations, as revealed by susceptibility to triggering by teleseismic waves and amplitude modulation by weak tidal stressing. In the rare cases for which good location is possible, ETS most often unfolds near or well below the lower edge of the seismogenic portion of major faults, perhaps marking the transition between locked and freely slipping rheologies. Mechanically, it appears sensible that fluids play an integral role regulating the ETS process, although how fluids would be able to mediate ETS episodes spanning 100+ km of fault is a head- scratcher. Maybe ETS regions underlie most locked faults. Maybe ETS offers possibilities to delineate locked faults and detail their temporal loading with clues to when they will erupt. This story is still unfolding.

  4. Quality of life and personality in essential tremor patients.

    Science.gov (United States)

    Lorenz, Delia; Schwieger, Daniel; Moises, Hans; Deuschl, Günther

    2006-08-01

    The aim of this study was to determine the impact of essential tremor (ET) on quality of life and its relation with tremor severity and the personality profile of ET patients. One hundred and five patients with definite or probable ET from an outpatient population were tested with the Short-Form 36-Item Health Survey (SF36) and the Eysenck Personality Questionnaire (EPQ-R). Compared to controls, the ET patients scored worse in all eight domains of the SF36. The physical component score (PCS) did not differ significantly from the normal population, whereas ET patients older than 40 years were significantly more affected with regard to the mental domains measured by the mental component score (MCS) with their median below the 20th percentile of the German controls. Tremor severity correlated with some of the physical domains and the PCS as well as with social function of the mental domains. ET patients showed significantly lower scores in the psychoticism (P) scale of the EPQ-R, with a median value on the 11th percentile of normal German population, indicating a more tender-minded personality type. The MCS correlated highly significant with the neuroticism (N) scale and extraversion (E) scale of EPQ-R. Multiple regression analysis identified age as the only predictive factor for the PCS and the N-scale as the only predictive factor for the MCS. Although ET is considered a pure movement disorder, the mental components of quality of life are more affected than the physical dimensions. A more controlled personality type may in part contribute to this.

  5. Mutation Analysis of HTRA2 Gene in Chinese Familial Essential Tremor and Familial Parkinson's Disease.

    Science.gov (United States)

    He, Ya-Chao; Huang, Pei; Li, Qiong-Qiong; Sun, Qian; Li, Dun-Hui; Wang, Tian; Shen, Jun-Yi; Du, Juan-Juan; Cui, Shi-Shuang; Gao, Chao; Fu, Rao; Chen, Sheng-Di

    2017-01-01

    Background. HTRA2 has already been nominated as PARK13 which may cause Parkinson's disease, though there are still discrepancies among these results. Recently, Gulsuner et al.'s study found that HTRA2 p.G399S is responsible for hereditary essential tremor and homozygotes of this allele develop Parkinson's disease by examining a six-generation family segregating essential tremor and essential tremor coexisting with Parkinson's disease. We performed this study to validate the condition of HTRA2 gene in Chinese familial essential tremor and familial Parkinson's disease patients, especially essential tremor. Methods. We directly sequenced all eight exons, exon-intron boundaries, and part of the introns in 101 familial essential tremor patients, 105 familial Parkinson's disease patients, and 100 healthy controls. Results. No exonic variant was identified, while one exon-intron boundary variant (rs2241028) and one intron variant (rs2241027) were detected, both with no clinical significance and uncertain function. There was no difference in allele, genotype, and haplotype between groups. Conclusions. HTRA2 exonic variant might be rare among Chinese Parkinson's disease and essential tremor patients with family history, and HTRA2 may not be the cause of familial Parkinson's disease and essential tremor in China.

  6. Motor network disruption in essential tremor : a functional and effective connectivity study

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; van der Stouwe, A. M. Madelein; Broersma, Marja; Sharifi, Sarvi; Groot, Paul F. C.; Speelman, Johannes D.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    2015-01-01

    Although involvement of the cerebello-thalamo-cortical network has often been suggested in essential tremor, the source of oscillatory activity remains largely unknown. To elucidate mechanisms of tremor generation, it is of crucial importance to study the dynamics within the

  7. Continuous theta-burst stimulation of the primary motor cortex in essential tremor

    DEFF Research Database (Denmark)

    Hellriegel, Helge; Schulz, Eva M; Siebner, Hartwig R

    2012-01-01

    We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation.......We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation....

  8. Motor imagery evokes increased somatosensory activity in parkinson's disease patients with tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2012-01-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and wheth

  9. Motor imagery evokes increased somatosensory activity in parkinson's disease patients with tremor.

    NARCIS (Netherlands)

    Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2012-01-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and wheth

  10. Design and validation of a rehabilitation robotic exoskeleton for tremor assessment and suppression.

    Science.gov (United States)

    Rocon, E; Belda-Lois, J M; Ruiz, A F; Manto, M; Moreno, J C; Pons, J L

    2007-09-01

    Exoskeletons are mechatronic systems worn by a person in such a way that the physical interface permits a direct transfer of mechanical power and exchange of information. Upper limb robotic exoskeletons may be helpful for people with disabilities and/or limb weakness or injury. Tremor is the most common movement disorder in neurological practice. In addition to medication, rehabilitation programs, and deep brain stimulation, biomechanical loading has appeared as a potential tremor suppression alternative. This paper introduces the robotic exoskeleton called WOTAS (wearable orthosis for tremor assessment and suppression) that provides a means of testing and validating nongrounded control strategies for orthotic tremor suppression. This paper describes in detail the general concept for WOTAS, outlining the special features of the design and selection of system components. Two control strategies developed for tremor suppression with exoskeletons are described. These two strategies are based on biomechanical loading and notch filtering the tremor through the application of internal forces. Results from experiments using these two strategies on patients with tremor are summarized. Finally, results from clinical trials are presented, which indicate the feasibility of ambulatory mechanical suppression of tremor.

  11. Hypertrophic Olivary Degeneration and Palatal or Oculopalatal Tremor

    Directory of Open Access Journals (Sweden)

    Caroline Tilikete

    2017-06-01

    Full Text Available Hypertrophic degeneration of the inferior olive is mainly observed in patients developing palatal tremor (PT or oculopalatal tremor (OPT. This syndrome manifests as a synchronous tremor of the palate (PT and/or eyes (OPT that may also involve other muscles from the branchial arches. It is associated with hypertrophic inferior olivary degeneration that is characterized by enlarged and vacuolated neurons, increased number and size of astrocytes, severe fibrillary gliosis, and demyelination. It appears on MRI as an increased T2/FLAIR signal intensity and enlargement of the inferior olive. There are two main conditions in which hypertrophic degeneration of the inferior olive occurs. The most frequent, studied, and reported condition is the development of PT/OPT and hypertrophic degeneration of the inferior olive in the weeks or months following a structural brainstem or cerebellar lesion. This “symptomatic” condition requires a destructive lesion in the Guillain–Mollaret pathway, which spans from the contralateral dentate nucleus via the brachium conjunctivum and the ipsilateral central tegmental tract innervating the inferior olive. The most frequent etiologies of destructive lesion are stroke (hemorrhagic more often than ischemic, brain trauma, brainstem tumors, and surgical or gamma knife treatment of brainstem cavernoma. The most accepted explanation for this symptomatic PT/OPT is that denervated olivary neurons released from inhibitory inputs enlarge and develop sustained synchronized oscillations. The cerebellum then modulates/accentuates this signal resulting in abnormal motor output in the branchial arches. In a second condition, PT/OPT and progressive cerebellar ataxia occurs in patients without structural brainstem or cerebellar lesion, other than cerebellar atrophy. This syndrome of progressive ataxia and palatal tremor may be sporadic or familial. In the familial form, where hypertrophic degeneration of the inferior olive may not

  12. Tectonic Tremor Triggered along Major Strike-Slip Faults around the World

    Science.gov (United States)

    Aiken, C.; Peng, Z.; Shelly, D. R.; Hill, D. P.; Gonzalez-Huizar, H.; Chao, K.; Zimmerman, J. P.; Douilly, R.; Deschamps, A.; Haase, J. S.; Calais, E.

    2013-12-01

    Over the last decade, deep tectonic tremor has been observed at several major plate-bounding faults around the Pacific Rim. Observations in these regions show that ambient tremor occurs spontaneously in association with geodetically detectable slow-slip events and that triggered tremor occurs in response to small stress perturbations arising from solid earth tides as well as passing seismic waves of a distant earthquake. Tremor generally occurs in the lower crust, beneath the seismogenic zone where earthquakes occur. In order to investigate the potential link between tremor and earthquake nucleation, further study of when, where, and how tremor occurs is needed. Here, we present a review of remotely triggered tectonic tremor in four strike-slip regions: (1) the Queen Charlotte Fault near Haida Gwaii, Canada, (2) the Eastern Denali Fault in Yukon, Canada, (3) the Enriquillo-Plantain Garden Fault in the southern Haiti peninsula, and (4) the Parkfield-Cholame segment of the San Andreas Fault near Parkfield, California. In Haida Gwaii, Yukon and Parkfield, we first compute the estimated dynamic stress for all magnitude ≥ 5.5 earthquakes based on the magnitude listed in the Advanced National Seismograph System (ANSS) earthquake catalog and epicentral distance to the region where tremor is observed. We then retrieve seismic data from local networks for earthquakes that are estimated to generate ≥ 1 kPa dynamic stress, without regard to epicentral distance. We characterize tremor triggered by these distant earthquakes as broadband signals with long duration that are coincident with surface waves from a distant event or occur in a large cluster immediately following the teleseismic wavetrain. In Haiti, a temporary seismic network was deployed shortly after the 2010/01/12 Mw7.0 Haiti earthquake. Thus, we are only able to report on triggering by the 2010/02/27 Mw8.8 Maule, Chile earthquake that occurred shortly thereafter. In Parkfield, we use a low-frequency earthquake

  13. Head Injuries

    Science.gov (United States)

    ... object that's stuck in the wound. previous continue Concussions Concussions — the temporary loss of normal brain function due ... also a type of internal head injury. Repeated concussions can permanently damage the brain. In many cases, ...

  14. Head Tilt

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & ... When this happens, the neck muscles go into spasm, causing the head to tilt to one side. ...

  15. Head Injuries

    Science.gov (United States)

    ... ATV) Safety Balance Disorders Knowing Your Child's Medical History First Aid: Falls First Aid: Head Injuries Preventing Children's Sports Injuries Getting Help: Know the Numbers Concussions Stay Safe: Baseball Concussions Concussions: Getting Better Sports and Concussions Dealing ...

  16. Head MRI

    Science.gov (United States)

    ... heart valves Heart defibrillator or pacemaker Inner ear (cochlear) implants Kidney disease or dialysis (you may not ... to: Abnormal blood vessels in the brain ( arteriovenous malformations of the head ) Tumor of the nerve that ...

  17. Thalamic deep brain stimulation for the treatment of tremor due to multiple sclerosis: a prospective study of tremor and quality of life.

    Science.gov (United States)

    Berk, Caglar; Carr, Jason; Sinden, Marci; Martzke, Jeff; Honey, Christopher R

    2002-10-01

    In several studies a significant reduction in tremor after thalamic deep brain stimulation (DBS) has been reported among patients with multiple sclerosis (MS). It has not been determined if this results in an improved quality of life. In this study the authors prospectively evaluated the effects of thalamic DBS on tremor and quality of life. Videotapes of the patients' tremor were made preoperatively and 2 and 12 months postoperatively, and tremor was scored by a neurologist blinded to the treatment. Patients were tested pre- and postoperatively to measure any changes in their reported ability to perform selected activities of daily living and in their health-related quality of life. Patients were asked to complete a questionnaire about their satisfaction with the surgery. Postoperative changes were examined using paired t-tests. There were significant reductions in postural, action, and overall tremor at 2 and 12 months postoperatively. The patients' reported ability to feed themselves was significantly improved 2 months after surgery (p = 0.01). There were short-term trends toward improvement in reported dressing ability, personal hygiene, and writing. There were no significant changes in the SF-36 subscales or total score. In this cohort of patients with MS who suffered from tremor, thalamic DBS significantly improved their tremor and ability to feed themselves. Patient satisfaction with the procedure, however, was variable. Preoperative patient education about what functions might (and might not) be improved is crucial to avoid unrealistic expectations. Our results indicate that younger patients with MS tremor who had a shorter disease duration and no superimposed ataxia benefited most from this surgery.

  18. Tremor-genic slow slip regions may be deeper and warmer and may slip slower than non-tremor-genic regions

    Science.gov (United States)

    Montgomery-Brown, Emily; Syracuse, Ellen M.

    2015-01-01

    Slow slip events (SSEs) are observed worldwide and often coincide with tectonic tremor. Notable examples of SSEs lacking observed tectonic tremor, however, occur beneath Kīlauea Volcano, Hawaii, the Boso Peninsula, Japan, near San Juan Bautista on the San Andreas Fault, California, and recently in Central Ecuador. These SSEs are similar to other worldwide SSEs in many ways (e.g., size or duration), but lack the concurrent tectonic tremor observed elsewhere; instead, they trigger swarms of regular earthquakes. We investigate the physical conditions that may distinguish these non-tremor-genic SSEs from those associated with tectonic tremor, including slip velocity, pressure, temperature, fluids, and fault asperities, although we cannot eliminate the possibility that tectonic tremor may be obscured in highly attenuating regions. Slip velocities of SSEs at Kīlauea Volcano (∼10−6 m/s) and Boso Peninsula (∼10−7 m/s) are among the fastest SSEs worldwide. Kīlauea Volcano, the Boso Peninsula, and Central Ecuador are also among the shallowest SSEs worldwide, and thus have lower confining pressures and cooler temperatures in their respective slow slip zones. Fluids also likely contribute to tremor generation, and no corresponding zone of high vp/vs has been noted at Kīlauea or Boso. We suggest that the relatively faster slip velocities at Kīlauea Volcano and the Boso Peninsula result from specific physical conditions that may also be responsible for triggering swarms of regular earthquakes adjacent to the slow slip, while different conditions produce slower SSE velocities elsewhere and trigger tectonic tremor.

  19. Disruption of nigrostriatal and cerebellothalamic pathways in dopamine responsive Holmes' tremor.

    Science.gov (United States)

    Seidel, S; Kasprian, G; Leutmezer, F; Prayer, D; Auff, E

    2009-08-01

    Holmes' tremor is an unusual combination of rest, postural and kinetic tremor of the extremities. Medical treatment of this condition still remains unsatisfactory. The case of a 20-year-old female patient is reported who developed right-sided Holmes' tremor 9 months after a left-sided, cavernoma induced midbrain/pontine haemorrhage at the age of 16 years. Beta-CIT single photon emission computed tomography revealed abolished dopamine transporter activity in the left basal ganglia and striatum, in accordance with missing ipsilateral tegmento-frontal connectivity (medial forebrain bundle), demonstrated by diffusion tensor MRI. Tractography showed reduced fibre connectivity of the superior and middle cerebellar peduncles on the lesioned side. Administration of pramipexole and L-DOPA led to a clinically significant reduction in tremor severity. In conclusion, our results support the notion that Holmes' tremor was a result of diminished striatal dopaminergic input in our patient.

  20. Quantification of a secondary task-specific tremor in a violinist after a temporal lobectomy.

    Science.gov (United States)

    Lee, André; Tominaga, Kenta; Furuya, Shinichi; Miyazaki, Fumio; Altenmüller, Eckart

    2014-01-01

    Task-specific tremors (TSTs) occur mainly during certain tasks and may be highly disabling. In this case study, we report on a 66-year-old violinist who developed a TST of the right arm only while playing the violin 4 weeks after a temporal lobectomy, which had been performed as a result of his temporal lobe epilepsy. Since a similar case, to our knowledge, has not been reported so far, our aim was to quantitatively assess and describe the tremor by measuring (a) the electromyography (EMG) activity of the wrist flexor and extensor as well as (b) an accelerometer signal of the hand. We found a tremor-related frequency of about 7 Hz. Furthermore, at a similar frequency of about 7 Hz, there was coherence between the tremor acceleration and EMG-activity of the wrist flexor and extensor as well as between the tremor acceleration and coactivation. The tremorgenesis remains unclear, and possible explanations can only be speculative.

  1. Chrysanthemyl diphosphate synthase: Isolation of the gene and characterization of the recombinant non-head-to-tail monoterpene synthase from Chrysanthemum cinerariaefolium

    OpenAIRE

    Rivera, Susan B.; Swedlund, Bradley D.; King, Gretchen J.; Bell, Russell N.; Hussey, Charles E.; Shattuck-Eidens, Donna M.; Wrobel, Wislawa M.; Peiser, Galen D.; Poulter, C. Dale

    2001-01-01

    Chrysanthemyl diphosphate synthase (CPPase) catalyzes the condensation of two molecules of dimethylallyl diphosphate to produce chrysanthemyl diphosphate (CPP), a monoterpene with a non-head-to-tail or irregular c1′-2-3 linkage between isoprenoid units. Irregular monoterpenes are common in Chrysanthemum cinerariaefolium and related members of the Asteraceae family. In C. cinerariaefolium, CPP is an intermediate in the biosynthesis of the pyrethrin ester insecticides. CPPa...

  2. Parkinsonian Rest Tremor Is Associated With Modulations of Subthalamic High-Frequency Oscillations.

    Science.gov (United States)

    Hirschmann, Jan; Butz, Markus; Hartmann, Christian J; Hoogenboom, Nienke; Özkurt, Tolga E; Vesper, Jan; Wojtecki, Lars; Schnitzler, Alfons

    2016-10-01

    High frequency oscillations (>200 Hz) have been observed in the basal ganglia of PD patients and were shown to be modulated by the administration of levodopa and voluntary movement. The objective of this study was to test whether the power of high-frequency oscillations in the STN is associated with spontaneous manifestation of parkinsonian rest tremor. The electromyogram of both forearms and local field potentials from the STN were recorded in 11 PD patients (10 men, age 58 [9.4] years, disease duration 9.2 [6.3] years). Patients were recorded at rest and while performing repetitive hand movements before and after levodopa intake. High-frequency oscillation power was compared across epochs containing rest tremor, tremor-free rest, or voluntary movement and related to the tremor cycle. We observed prominent slow (200-300 Hz) and fast (300-400 Hz) high-frequency oscillations. The ratio between slow and fast high-frequency oscillation power increased when tremor became manifest. This increase was consistent across nuclei (94%) and occurred in medication ON and OFF. The ratio outperformed other potential markers of tremor, such as power at individual tremor frequency, beta power, or low gamma power. For voluntary movement, we did not observe a significant difference when compared with rest or rest tremor. Finally, rhythmic modulations of high-frequency oscillation power occurred within the tremor cycle. Subthalamic high-frequency oscillation power is closely linked to the occurrence of parkinsonian rest tremor. The balance between slow and fast high-frequency oscillation power combines information on motor and medication state. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  3. Quantification of high pressure nervous syndrome (HPNS) tremor in the guinea pig.

    Science.gov (United States)

    Gruenau, S P; Ackermann, M J

    1978-03-01

    Previous studies have demonstrated two tremorgenic systems that involve separate brain mechanisms and exhibit different peak frequencies. One system (the thalamo-cortical) generates low frequency (4--8 Hz) tremor; the other (the olivo-cerebellar) produces high frequency (10--18 Hz) tremor. Based on this evidence, the present study focused on determining whether one or both of these tremor systems is involved in the high pressure nervous syndrome (HPNS). Specifically, the concern was to identify and to quantify amplitude and frequency characteristics of HPNS tremor in 8 guinea pigs breathing helium-oxygen during compression (40 ft/min) in a chamber dive to 61.6 ATA (2000 fsw) with a bottom time of 1 h. Rectal temperature was recorded and maintained at 39 degrees C +/- 1 degree. Leg tremor was recorded by magnetic inductance and stored on magnetic tape for power spectral analysis. Frequency histograms of the tremor data revealed development of a biphasic response. From surface to about 31.3 ATA (1000 fsw), a low-power, single, 4- to 6-Hz component was evident, which resembled fine or moderate tremor. Between 34.3 ATA (1100 fsw) and 61.6 ATA, a 12- to 18-Hz component emerged abruptly with a dramatic increase in power, which reflected coarse, uncontrollable tremors. In the first 5 to 10 min after the animals arrived at maximum pressure, relative power of the high frequency component dropped to and remained near base-line levels. These results support the hypothesis that HPNS tremor consists of two components and possibly two separate tremor systems.

  4. The complete frequency spectrum of physiological tremor can be recreated by broadband mechanical or electrical drive.

    Science.gov (United States)

    Vernooij, Carlijn Andrea; Lakie, Martin; Reynolds, Raymond Francis

    2015-01-15

    Two frequency peaks of variable preponderance have been reported for human physiological finger tremor. The high-frequency peak (20-25 Hz, seen only in postural tremor) is generally attributed to mechanical resonance, whereas the lower frequency peak (8-12 Hz, seen in both postural and kinetic tremor) is usually attributed to synchronous central or reflexive neural drive. In this study, we determine whether mechanical resonance could generate both peaks. In relaxed subjects, an artificial finger tremor was evoked by random mechanical perturbations of the middle finger or random electrical muscular stimulation of the finger extensor muscle. The high and the low frequencies observed in physiological tremor could both be created by either type of artificial input at appropriate input intensity. Resonance, inferred from cross-spectral gain and phase, occurred at both frequencies. To determine any neural contribution, we compared truly passive subjects with those who exhibited some electromyographic (EMG) activity in the finger extensor; artificially created tremor spectra were almost identical between groups. We also applied electrical stimuli to two clinically deafferented subjects lacking stretch reflexes. They exhibited the same artificial tremor spectrum as control subjects. These results suggest that both typical physiological finger tremor frequencies can be reproduced by random artificial input; neither requires synchronized neural input. We therefore suggest that mechanical resonance could generate both dominant frequency peaks characteristic of physiological finger tremor. The inverse relationship between the input intensity and the resulting tremor frequency can be explained by a movement-dependent reduction in muscle stiffness, a conjecture we support using a simple computational model.

  5. Using Seismic Arrays to Detect Triggered and Ambient Tremor in Taiwan

    Science.gov (United States)

    Sun, W.; Peng, Z.; Lin, C.; Chao, K.

    2013-12-01

    Deep tectonic tremor triggered by teleseismic surface waves have been recently observed in the southern Central Range in Taiwan, an arc-continental type collision environment. Aiming to capture more tremor events, we installed two dense 36-element, small-aperture seismic arrays in 2011 around the Liouguei and Lidao areas, which are located about 20 km in southwest and northeast to the tremor sources. In each array, short-period, vertical-channel GS-11D sensors with 4.5Hz natural frequency seismometers were laid out on the relatively flat parts of the mountain areas with a spacing of approximately 100 by 80 meters. We had successfully recorded continuously for a total of 4,034 hours in 2011. As expected, the two arrays recorded tremor bursts triggered by the great Tohoku earthquake (Mw=9.0) on March 11, 2011. We apply the broadband frequency wavenumber (BBFK) beamforming method to measure the back-azimuth and incident angles for each tremor burst and through the whole data set. Our initial results show that obtained array parameters closely match those predicted from locations using tremor envelope cross-correlations (WECC) and we detect more tremor duration by BBFK than WECC. We further use a moving-window grid-search (MWGS) method to detect regular earthquakes. Our result indicates the southwestern array provides more stable results than the northeastern array. Our next step is to apply the same MWGS procedure to detect ambient tremor recorded by the southwestern array. Our systematic analysis of deep tremor in Taiwan could help to better understand critical conditions related to tremor occurrence and fault mechanics at the bottom of the seismogenic layer.

  6. Episodic Tremor and Slip (ETS) as a chaotic multiphysics spring

    Science.gov (United States)

    Veveakis, E.; Alevizos, S.; Poulet, T.

    2017-03-01

    Episodic Tremor and Slip (ETS) events display a rich behaviour of slow and accelerated slip with simple oscillatory to complicated chaotic time series. It is commonly believed that the fast events appearing as non volcanic tremors are signatures of deep fluid injection. The fluid source is suggested to be related to the breakdown of hydrous phyllosilicates, mainly the serpentinite group minerals such as antigorite or lizardite that are widespread in the top of the slab in subduction environments. Similar ETS sequences are recorded in different lithologies in exhumed crustal carbonate-rich thrusts where the fluid source is suggested to be the more vigorous carbonate decomposition reaction. If indeed both types of events can be understood and modelled by the same generic fluid release reaction AB(solid) ⇌A(solid) +B(fluid) , the data from ETS sequences in subduction zones reveal a geophysically tractable temporal evolution with no access to the fault zone. This work reviews recent advances in modelling ETS events considering the multiphysics instabilities triggered by the fluid release reaction and develops a thermal-hydraulic-mechanical-chemical oscillator (THMC spring) model for such mineral reactions (like dehydration and decomposition) in Megathrusts. We describe advanced computational methods for THMC instabilities and discuss spectral element and finite element solutions. We apply the presented numerical methods to field examples of this important mechanism and reproduce the temporal signature of the Cascadia and Hikurangi trench with a serpentinite oscillator.

  7. Fragile X-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Hagerman, Paul J; Hagerman, Randi J

    2015-03-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some but not all carriers of small, noncoding CGG-repeat expansions (55-200 repeats; premutation) within the fragile X gene (FMR1). Principal features of FXTAS include intention tremor, cerebellar ataxia, Parkinsonism, memory and executive function deficits, autonomic dysfunction, brain atrophy with white matter disease, and cognitive decline. Although FXTAS was originally considered to be confined to the premutation range, rare individuals with a gray zone (45-54 repeats) or an unmethylated full mutation (>200 repeats) allele have now been described, the constant feature of the disorder remaining the requirement for FMR1 expression, in contradistinction to the gene silencing mechanism of fragile X syndrome. Although transcriptional activity is required for FXTAS pathogenesis, the specific trigger(s) for FXTAS pathogenesis remains elusive, highlighting the need for more research in this area. This need is underscored by recent neuroimaging findings of changes in the central nervous system that consistently appear well before the onset of clinical symptoms, thus creating an opportunity to delay or prevent the appearance of FXTAS. © 2015 New York Academy of Sciences.

  8. A double-correlation tremor-location method

    Science.gov (United States)

    Li, Ka Lok; Sgattoni, Giulia; Sadeghisorkhani, Hamzeh; Roberts, Roland; Gudmundsson, Olafur

    2017-02-01

    A double-correlation method is introduced to locate tremor sources based on stacks of complex, doubly-correlated tremor records of multiple triplets of seismographs back projected to hypothetical source locations in a geographic grid. Peaks in the resulting stack of moduli are inferred source locations. The stack of the moduli is a robust measure of energy radiated from a point source or point sources even when the velocity information is imprecise. Application to real data shows how double correlation focuses the source mapping compared to the common single correlation approach. Synthetic tests demonstrate the robustness of the method and its resolution limitations which are controlled by the station geometry, the finite frequency of the signal, the quality of the used velocity information and noise level. Both random noise and signal or noise correlated at time shifts that are inconsistent with the assumed velocity structure can be effectively suppressed. Assuming a surface wave velocity, we can constrain the source location even if the surface wave component does not dominate. The method can also in principle be used with body waves in 3-D, although this requires more data and seismographs placed near the source for depth resolution.

  9. Linking Essential Tremor to the Cerebellum: Physiological Evidence.

    Science.gov (United States)

    Filip, Pavel; Lungu, Ovidiu V; Manto, Mario-Ubaldo; Bareš, Martin

    2016-12-01

    Essential tremor (ET), clinically characterized by postural and kinetic tremors, predominantly in the upper extremities, originates from pathological activity in the dynamic oscillatory network comprising the majority of nodes in the central motor network. Evidence indicates dysfunction in the thalamus, the olivocerebellar loops, and intermittent cortical engagement. Pathology of the cerebellum, a structure with architecture intrinsically predisposed to oscillatory activity, has also been implicated in ET as shown by clinical, neuroimaging, and pathological studies. Despite electrophysiological studies assessing cerebellar impairment in ET being scarce, their impact is tangible, as summarized in this review. The electromyography-magnetoencephalography combination provided the first direct evidence of pathological alteration in cortico-subcortical communication, with a significant emphasis on the cerebellum. Furthermore, complex electromyography studies showed disruptions in the timing of agonist and antagonist muscle activation, a process generally attributed to the cerebellum. Evidence pointing to cerebellar engagement in ET has also been found in electrooculography measurements, cerebellar repetitive transcranial magnetic stimulation studies, and, indirectly, in complex analyses of the activity of the ventral intermediate thalamic nucleus (an area primarily receiving inputs from the cerebellum), which is also used in the advanced treatment of ET. In summary, further progress in therapy will require comprehensive electrophysiological and physiological analyses to elucidate the precise mechanisms leading to disease symptoms. The cerebellum, as a major node of this dynamic oscillatory network, requires further study to aid this endeavor.

  10. Knowledge gaps and research recommendations for essential tremor.

    Science.gov (United States)

    Hopfner, Franziska; Haubenberger, Dietrich; Galpern, Wendy R; Gwinn, Katrina; Van't Veer, Ashlee; White, Samantha; Bhatia, Kailash; Adler, Charles H; Eidelberg, David; Ondo, William; Stebbins, Glenn T; Tanner, Caroline M; Helmich, Rick C; Lenz, Fred A; Sillitoe, Roy V; Vaillancourt, David; Vitek, Jerrold L; Louis, Elan D; Shill, Holly A; Frosch, Matthew P; Foroud, Tatiana; Kuhlenbäumer, Gregor; Singleton, Andrew; Testa, Claudia M; Hallett, Mark; Elble, Rodger; Deuschl, Günther

    2016-12-01

    Essential tremor (ET) is a common cause of significant disability, but its etiologies and pathogenesis are poorly understood. Research has been hampered by the variable definition of ET and by non-standardized research approaches. The National Institute of Neurological Disorders and Stroke (USA) invited experts in ET and related fields to discuss current knowledge, controversies, and gaps in our understanding of ET and to develop recommendations for future research. Discussion focused on phenomenology and phenotypes, therapies and clinical trials, pathophysiology, pathology, and genetics. Across all areas, the need for collaborative and coordinated research on a multinational level was expressed. Standardized data collection using common data elements for genetic, clinical, neurophysiological, and pathological studies was recommended. Large cohorts of patients should be studied prospectively to collect bio-samples, characterize the natural history of the clinical syndrome including patient-oriented outcomes, investigate potential etiologies of various phenotypes, and identify pathophysiological mechanisms. In particular, cellular and system-level mechanisms of tremor oscillations should be elucidated because they may yield effective therapeutic targets and biomarkers. A neuropathology consortium was recommended to standardize postmortem analysis and further characterize neuropathological observations in the cerebellum and elsewhere. Furthermore, genome-wide association studies on large patient cohorts (>10,000 patients) may allow the identification of common genes contributing to risk, and whole exome or genome sequencing may enable the identification of genetic risk and causal mutations in cohorts and well-characterized families.

  11. Zero torque gear head wrench

    Science.gov (United States)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  12. Spatial and Temporal Comparisons of Tremor and Slow Slip in Cascadia

    Science.gov (United States)

    Hall, K.; Houston, H.; Schmidt, D. A.

    2015-12-01

    Tremor is often thought to be a proxy for slip during ETS events and has been shown to have a relatively abrupt updip boundary, implying an abrupt updip limit of slip. However, as shown by Houston (AGU abstract, 2012) and Hall and Houston (AGU abstract, 2014), slip inferred from GPS extended updip of the seismically-detected tremor in the 2010 M6.8 and 2012 M6.7 ETS events. If slip extending updip of tremor is a persistent phenomena, tremor cannot be directly used as a proxy for slip. Following the methods used on the 2010 and 2012 ETS event, we found that the August 2009 ETS around Portland, OR also showed slip updip of tremor. Principal Component Analysis was implemented to automatically select the direction and magnitude of the maximum displacement vector. Our Green's functions use the Okada formulation of buried rectangular faults in a halfspace for a grid of 8x8 km subfaults based on the McCrory slab model. We then performed static inversions with 2nd order Tikhonov regularization to find slip on the fault surface. We also compared two different inversions for 2009, one where slip was allowed on a broad regional grid and a tremor-restricted inversion (TRI) where slip was restricted to subfaults in which tremor occurred. We found the 2009 ETS event released the equivalent of a M6.8 in slip. We also found that, as in the previous ETSs, the TRI forced up to 10 cm of slip to the updip edge of the grid, which is exceeds the amount of plate convergence expected in the inter-ETS periods and is therefore physically unsustainable over several ETS events. The excess slip along the updip edge in the TRI models also suggests that the geodetic data prefer slip with a larger footprint than the spatial pattern of tremor, and supports our conclusion that tremor does not represent all of the slip during an ETS event. We see consistent and clear spatial relationship between tremor and slip with some slip occurring updip of tremor. Our static inversions show where slip is

  13. Changes in physiological tremor associated with an epileptic seizure: a case report

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    Duval Christian

    2011-09-01

    Full Text Available Abstract Introduction Epileptic seizures are associated with motor, sensory, somatosensory or autonomic symptoms that have all been described in varying detail over the years. Of interest in the present report is a case of normal physiological tremor, which to date has never been evaluated prior to and during an epileptic seizure. In fact, there is only anecdotal mention of pre-ictal and ictal changes in clinically noticeable tremor in the literature. Case presentation Our patient was a left-handed, 27-year-old Caucasian woman diagnosed seven years previously with partial epileptic seizures, secondarily generalized. Physiological tremor was measured simultaneously on the index finger of both hands of our patient. Electromyography as well as heart rate and respiration were also monitored. A previously performed electroencephalography examination revealed abnormal oscillations focalized to the left primary somatosensory cortex. She was also diagnosed with left frontal neuronal heterotopias. We detected subclinical changes in tremor characteristics, such as amplitude, median power frequency and power dispersion, contralateral to the localization of epileptic activity. Tremor characteristics remained relatively steady ipsilateral to the localization of the epileptic activity. Conclusions Changes in physiological tremor characteristics should be considered as another possible pre-ictal or ictal manifestation. We propose that the network associated with physiological tremor might be more sensitive to abnormal oscillations generated within the central nervous system by epileptic activity from certain structures.

  14. Repeating deep tremors on the plate interface beneath Kyushu, southwest Japan

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    Yabe, Suguru; Ide, Satoshi

    2013-01-01

    In the subduction zone south of Kyushu Island, at the western extension of the Nankai subduction zone, southwest Japan, the age of the oceanic crust increases toward the south across the subducting Kyushu-Palau ridge. While tremor activity is very high in Nankai, tectonic tremors have only recently been discovered in Kyushu. In this study, we examined tremors beneath Kyushu using an improved version of the envelope correlation method. In doing so, we distinguished tremors from normal earthquakes and background noise using the criteria of source duration and the spectrum ratio between low and high frequencies. Accurate measurement of S- P times, using cross-correlation between vertical and horizontal seismograms, constrains the tremor depth precisely. Tremor activity is low and within a small region in southern Kyushu, where thick crust of the Kyushu-Palau ridge is being subducted, at depths between 35 and 45 km (i.e., shallower than intra-slab earthquakes by about 20 km), which is consistent with the location of the plate interface within uncertainties proposed in previous studies. Establishing precise depth estimates for tectonic tremors beneath Kyushu, which results from shear slip along the plate interface, is useful in defining the plate interface within the Nankai subduction zone.

  15. Deep brain stimulation or thalamotomy in fragile X-associated tremor/ataxia syndrome? Case report.

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    Tamás, Gertrúd; Kovács, Norbert; Varga, Noémi Ágnes; Barsi, Péter; Erőss, Loránd; Molnár, Mária Judit; Balás, István

    2016-01-01

    We present the case of a 66-year-old man who has been treated for essential tremor since the age of 58. He developed mild cerebellar gait ataxia seven years after tremor onset. Moderate, global brain atrophy was identified on MRI scans. At the age of 68, only temporary tremor relief could be achieved by bilateral deep brain stimulation of the ventral intermedius nucleus of the thalamus. Bilateral stimulation of the subthalamic nucleus also resulted only in transient improvement. In the meantime, progressive gait ataxia and tetraataxia developed accompanied by other cerebellar symptoms, such as nystagmus and scanning speech. These correlated with progressive development of bilateral symmetric hyperintensity of the middle cerebellar peduncles on T2 weighted MRI scans. Genetic testing revealed premutation of the FMR1 gene, establishing the diagnosis of fragile X-associated tremor/ataxia syndrome. Although this is a rare disorder, it should be taken into consideration during preoperative evaluation of essential tremor. Postural tremor ceased two years later after thalamotomy on the left side, while kinetic tremor of the right hand also improved.

  16. Strongly gliding harmonic tremor during the 2009 eruption of Redoubt Volcano

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    Hotovec, Alicia J.; Prejean, Stephanie G.; Vidale, John E.; Gomberg, Joan S.

    2013-01-01

    During the 2009 eruption of Redoubt Volcano, Alaska, gliding harmonic tremor occurred prominently before six nearly consecutive explosions during the second half of the eruptive sequence. The fundamental frequency repeatedly glided upward from < 1 Hz to as high as 30 Hz in less than 10 min, followed by a relative seismic quiescence of 10 to 60 s immediately prior to explosion. High frequency (5 to 20 Hz) gliding returned during the extrusive phase, and lasted for 20 min to 3 h at a time. Although harmonic tremor is not uncommon at volcanoes, tremor at such high frequencies is a rare observation. These frequencies approach or exceed the plausible upper limits of many models that have been suggested for volcanic tremor. We also analyzed the behavior of a swarm of repeating earthquakes that immediately preceded the first instance of pre-explosion gliding harmonic tremor. We find that these earthquakes share several traits with upward gliding harmonic tremor, and favor the explanation that the gliding harmonic tremor at Redoubt Volcano is created by the superposition of increasingly frequent and regular, repeating stick–slip earthquakes through the Dirac comb effect.

  17. Augmented visual feedback counteracts the effects of surface muscular functional electrical stimulation on physiological tremor.

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    Grimaldi, Giuliana; Fernandez, Alfredo; Manto, Mario

    2013-09-24

    Recent studies suggest that surface muscular functional electrical stimulation (FES) might suppress neurological upper limb tremor. We assessed its effects on upper limb physiological tremor, which is mainly driven by mechanical-reflex oscillations. We investigated the interaction between FES and augmented visual feedback, since (a) most daily activities are performed using visual cues, and (b) augmented visual feedback exacerbates upper limb tremor. 10 healthy subjects (23.4 ± 7.7 years) performed 2 postural tasks with combinations of FES (4 sites; frequency of stimulation: 30 Hz; pulse width: 300 microsec; range of current delivered 10-34 mAmp) and augmented visual feedback. Spectral analysis of tremor showed a decrease of power spectral density to 62.18% (p = 0.01), of the integral in the 8-12 Hz frequency band to 57.67% (p = 0.003), and of tremor root mean square (RMS) to 57.16% (p = 0.002) during FES, without any changes in tremor frequency. Augmented visual feedback blocked the beneficial effect of FES, as confirmed by power spectral analysis (p = 0.01). We found a statistically significant interaction between augmented visual feedback and electrical stimulation (p = 0.039). Augmented visual feedback antagonizes the effects of FES on physiological tremor. The absence of changes of peak frequency argues against an effect of FES on mechanical properties of the upper limb.

  18. The resonant component of human physiological hand tremor is altered by slow voluntary movements.

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    Lakie, Martin; Vernooij, Carlijn A; Osborne, Timothy M; Reynolds, Raymond F

    2012-05-15

    Limb resonance imparts a characteristic spectrum to hand tremor. Movement will alter the resonance. We have examined the consequences of this change. Rectified forearm extensor muscle EMG and physiological hand tremor were recorded. In postural conditions the EMG spectrum is relatively flat whereas the acceleration spectrum is sharply peaked. Consequently, the gain between EMG and acceleration is maximal at the frequency where the tremor is largest (∼8 Hz). The shape of the gain curve implies mechanical resonance. Substantial alterations in posture do not significantly change the characteristics of the tremor or the shape or size of the gain curve. By contrast, slow or moderately paced voluntary wrist flexion–extension movements dramatically increase the hand tremor size and lower its peak frequency. These changes in size and frequency of the tremor cannot be attributed to changes in the EMG. Instead they reflect a very large change in the size and shape of the gain curve relating EMG to acceleration. The gain becomes larger and the peak moves to a lower frequency (∼6 Hz). We suggest that a movement-related (thixotropic) alteration in resonant properties of the wrist provides a simple explanation for these changes. The mechanism is illustrated by a model. Our new findings confirm that resonance plays a major role in wrist tremor. We also demonstrate that muscles operate very differently under postural and dynamic conditions. The different coupling between EMG and movement in posture and when moving must pose a considerable challenge for neural predictive control of skeletal muscles.

  19. Atypical Porcine Pestivirus: A Possible Cause of Congenital Tremor Type A‐II in Newborn Piglets

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    Ad de Groof

    2016-10-01

    Full Text Available Congenital tremor type A‐II in piglets has been regarded as a transmissible disease since the 1970s, possibly caused by a very recently‐described virus: atypical porcine pestivirus (APPV. Here, we describe several strains of APPV in piglets with clinical signs of congenital tremor (10 of 10 farms tested. Piglets on a farm with no history of congenital tremor were PCR‐negative for the virus. To demonstrate a causal relationship between APPV and disease, three gilts were inoculated via intramuscular injection at day 32 of pregnancy. In two of the three litters, vertical transmission of the virus occurred. Clinical signs of congenital tremor were observed in APPV‐infected newborns, yet also two asymptomatic carriers were among the offspring. Piglets of one litter were PCR‐negative for the virus, and these piglets were all without congenital tremors. Long‐term follow up of farm piglets born with congenital tremors showed that the initially high viremia in serum declines at five months of age, but shedding of the virus in feces continues, which explains why the virus remains present at affected farms and causes new outbreaks. We conclude that trans‐placental transmission of APPV and subsequent infection of the fetuses is a very likely cause of congenital tremor type A‐II in piglets.

  20. Tremors along the Queen Charlotte Margin triggered by large teleseismic earthquakes

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    Aiken, Chastity; Peng, Zhigang; Chao, Kevin

    2013-03-01

    We conduct a systematic search of tectonic tremors along the Queen Charlotte Margin (QCM) in western Canada triggered by distant earthquakes. We identify triggered tremor as non-impulsive, high-frequency signals coherent among several stations and coincident with passing surface waves. So far, the 2002 Mw7.9 Denali Fault, the 2004 Mw9.2 Sumatra, and the 2011 Mw9.1 Tohoku-Oki earthquakes have triggered clear tremor in this region. The 2010 Mw8.8 Maule, Chile and the 2012 Mw8.6 Sumatra earthquakes may have triggered, but tremors in these two cases did not meet all of our criteria. The triggered tremors are mostly located east of the Queen Charlotte Fault in the southern portion of Haida Gwaii, near the epicenter of the 28 October 2012 Mw7.7 earthquake. Similar to the observations in other regions, the triggered tremors were initiated by the Love waves and continued during the subsequent Rayleigh waves. Tremor bursts correlate with both the particle velocity and displacement of the Love waves, indicating they are triggered at either low-angle thrust or vertical strike-slip faults. In addition, we find that the triggering potential for the QCM is controlled by a combination of amplitude, period, and incident angles.

  1. Atypical Porcine Pestivirus: A Possible Cause of Congenital Tremor Type A-II in Newborn Piglets

    Science.gov (United States)

    de Groof, Ad; Deijs, Martin; Guelen, Lars; van Grinsven, Lotte; van Os-Galdos, Laura; Vogels, Wannes; Derks, Carmen; Cruijsen, Toine; Geurts, Victor; Vrijenhoek, Mieke; Suijskens, Janneke; van Doorn, Peter; van Leengoed, Leo; Schrier, Carla; van der Hoek, Lia

    2016-01-01

    Congenital tremor type A-II in piglets has been regarded as a transmissible disease since the 1970s, possibly caused by a very recently-described virus: atypical porcine pestivirus (APPV). Here, we describe several strains of APPV in piglets with clinical signs of congenital tremor (10 of 10 farms tested). Piglets on a farm with no history of congenital tremor were PCR-negative for the virus. To demonstrate a causal relationship between APPV and disease, three gilts were inoculated via intramuscular injection at day 32 of pregnancy. In two of the three litters, vertical transmission of the virus occurred. Clinical signs of congenital tremor were observed in APPV-infected newborns, yet also two asymptomatic carriers were among the offspring. Piglets of one litter were PCR-negative for the virus, and these piglets were all without congenital tremors. Long-term follow up of farm piglets born with congenital tremors showed that the initially high viremia in serum declines at five months of age, but shedding of the virus in feces continues, which explains why the virus remains present at affected farms and causes new outbreaks. We conclude that trans-placental transmission of APPV and subsequent infection of the fetuses is a very likely cause of congenital tremor type A-II in piglets. PMID:27782037

  2. Long-term outcome of deep brain stimulation in fragile X-associated tremor/ataxia syndrome.

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    Weiss, Daniel; Mielke, Carina; Wächter, Tobias; Bender, Benjamin; Liscic, Rajka M; Scholten, Marlieke; Naros, Georgios; Plewnia, Christian; Gharabaghi, Alireza; Krüger, Rejko

    2015-03-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) presents as complex movement disorder including tremor and cerebellar ataxia. The efficacy and safety of deep brain stimulation of the nucleus ventralis intermedius of the thalamus in atypical tremor syndromes like FXTAS remains to be determined. Here, we report the long-term outcome of three male genetically confirmed FXTAS patients treated with bilateral neurostimulation of the nucleus ventralis intermedius for up to four years. All patients demonstrated sustained improvement of both tremor and ataxia - the latter included improvement of intention tremor and axial tremor. Kinematic gait analyses further demonstrated a regularization of the gait cycle. Initial improvements of hand functional disability were not sustained and reached the preoperative level of impairment within one to two years from surgery. Our data on patients with a genetic cause of tremor show favorable outcome and may contribute to improved patient stratification for neurostimulation therapy in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Short-term spasmodic switching of volcanic tremor source activation in a conduit of the 2011 Kirishima eruption

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    Matsumoto, S.; Shimizu, H.; Matsushima, T.; Uehira, K.; Yamashita, Y.; Nakamoto, M.; Miyazaki, M.; Chikura, H.

    2012-04-01

    Volcanic tremors are seismic indicators providing clues for magma behavior, which is related to volcanic eruptions and activity. Detection of spatial and temporal variations of volcanic tremors is important for understanding the mechanism of volcanic eruptions. However, temporal variations of tremor activity in short-term than a minute have not been previously detected by seismological observations around volcanoes. Here, we show that volcanic tremor sources were activated at the top of the conduit (i.e. the crater) and at its lower end by analyzing seismograms from a dense seismic array during the 2011 Kirishima eruption. We observed spasmodic switching in the seismic ray direction during a volcanic tremor sequence. Such fine volcanic tremor structure suggests an interaction between tremor sources located in both deep and shallow depths. Our result suggests that seismic array observations can monitor the magma behavior and contribute to the evaluation of the activity's transition.

  4. TYPES OF TREMOR IN PATIENTS WITH CEREBROVASCULAR DISEASES AND CARDIOVASCULAR EVENTS

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    Petrov Igor

    2016-03-01

    Full Text Available Introduction: Tremor can occur as a part of the clinical feature of cerebrovascular diseases. Many patients with cerebral stroke have cardiovascular diseases as a comorbidity or complication of stroke; sometimes cardiovascular events can lead to embolic stroke. Aim: To present types of tremor in patients with cerebrovascular diseases and cardiovascular events and diabetes mellitus type 2, clinical characteristics of tremor and investigations used. Material and methods: In our study we included 36 patients, 24 men and 12 women, that were examined and followed for 3 years, from 2012-2015. All patients were subjected to the following investigations: neurological examination, laboratory analysis, computerized tomography of brain, magnetic resonance imaging and electroencephalography. In cardiovascular patients we also performed Doppler sonography of carotid arteries, electrocardiography, cardiac ultrasound. The patients were examined and treated by cardiologists. Results: Of all patients 22% had cerebral infarction, 41% atherosclerosis, 36% multiple lacunar infarctions and 28% diabetes mellitus type 2. Three patients with cerebral infarction had chorea, hemiballismus, dystonia and dystonic tremor, three had postural tremor and two cerebellar intention tremor. Atherosclerotic patients had atherosclerotic action tremor, while diabetic patients predominantly presented with action-type tremor. Electroencephalography showed irritative basic brain activity with slow waves, while carotid arteries stenosis was diagnosed by Doppler sonography. Computerized tomography of the brain and magnetic resonance imaging revealed cerebrovascular diseases in certain areas. Patients with cardiomyopathy, rhythm disorders, high blood pressure, hyperlipidemia was investigated and medically treated by a cardiologist. Conclusion: In cerebrovascular diseases different types of tremor can occur as the result of the damage of the extrapyramidal system.

  5. Non-Volcanic Tremor Near Parkfield, CA Systematically Excited by Teleseismic Waves

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    Peng, Z.; Vidale, J. E.; Rubinstein, J. L.; Gomberg, J.

    2007-12-01

    Non-volcanic tremor triggered by teleseismic waves was discovered recently along the subduction zones in Japan and Cascadia, and along the transform plate boundary in CA. Here we summarize non-volcanic tremor along the San Andreas fault (SAF) near Parkfield, CA triggered by the surface waves of regional and teleseismic events. We analyze 10 M ≥ 8.0 earthquakes since 2001, the M6.7 Nenana Mountain and M7.9 Denali, Alaska earthquakes in 2002 and the 2005 M7.2 Mendocino, California earthquake. We identify triggered tremor as bursts of high-frequency (~ 3-15 Hz), non-impulsive seismic energy that is coherent among many stations, and has a significant component in phase with the passing of the surface waves. We qualitatively judge the clarity of tremor observations and find the strongest, most coherent examples for the M7.9 Denali, M8.3 Hokkaido, M9.1 Sumatra, and M8.1 Kuril Islands earthquakes. The M6.7 Nenana Mountain earthquake did not trigger visible tremor, and the evidence for triggered tremor for the remaining 8 events is equivocal. The identification of tremor does not correlate strongly with peak ground velocity, but may correlate with cumulative energy density for long- period (≥ 30 s) surface waves. The observations suggest that longer-period waves may be a more effective trigger, most likely due to a better penetration to depth where tremors occur. Our observation, in concert with those of Gomberg et al., Vidale et al., and Rubinstein et al. [this meeting], suggests that non-volcanic tremor triggered by teleseismic waves is much more widespread than previously thought, and the effective stress, or the frictional coefficient is very low at depth along the SAF near Parkfield.

  6. Tectonic tremor and brittle seismic events triggered along the Eastern Denali Fault in northwest Canada

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    Zimmerman, J. P.; Aiken, C.; Peng, Z.

    2013-12-01

    Deep tectonic tremor has been observed in a number of plate-bounding tectonic environments around the world. It can occur both spontaneously (i.e. ambient) and as a result of small stress perturbations from passing seismic waves (i.e. triggered). Because tremor occurs beneath the seismogenic zone (> 15 km), it is important to understand where and how tremor occurs to discern its relationship with shallower earthquakes. In this study, we search for triggered tremor and brittle seismic events along the Eastern Denali Fault (EDF) in northwest Canada, an intraplate strike-slip region where previously tremor has not been observed. We retrieve seismic data for 19 distant earthquakes from 9 broadband stations monitored by the Canadian National Seismograph Network (CNSN). We apply high-pass or band-pass filters to the seismic data to suppress signals from distant events and search for local sources. Triggered tremor signals exhibit high-frequency contents, have long duration (> 15 s), are coincident with passing surface waves of the distant earthquakes, and are observable among nearby stations. Using this simple approach, we have identified 4 mainshocks that triggered tremor in our study region: the 2011/03/11 Mw9.1 Tohoku, 2012/04/11 Mw8.6 Sumatra, 2012/10/28 Mw7.7 Haida Gwaii, and 2013/01/05 Mw7.5 Craige earthquakes. Our initial locations indicate that the tremor source occurs on or near the southeastern portion of the EDF near the fault trace. In addition to the triggered tremor sources, we also identified many 'brittle' events with very short durations triggered by the Rayleigh waves of the 2012/10/28 Mw7.7 Haida Gwaii earthquake. While we were unable to locate these brittle events, they appear to be seismically similar to triggered icequakes observed in Antarctica (Peng et al., 2013) and occur during the dilatational strain changes caused by the Rayleigh waves.

  7. EFFECTS OF WRIST WEIGHING IN REDUCING UPPER LIMB TREMORS IN PATIENTS WITH CEREBELLAR LESIONS

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    Vishnu Priya

    2015-08-01

    Full Text Available Background: An intentional tremor is one of the most untreated causes in patients with cerebellar ataxia. Upper limb tremors decreases the performance of many activities of daily life Thus treatment of patients with tremor probably implies better functional ability. It is one of the major areas of concern to improve functional independence hence, this study proposed to know the effects of wrist weighing in reducing upper limb tremors in cerebellar injury patients. Materials and Methods: A total number of 21 patients with various abnormalities of cerebellum were selected depending on selection criteria. These patients were randomly divided into two groups. One group was treated with wrist weighing by using Velcro weight cuffs for 15 minutes along with conventional physiotherapy for 5 days a week for 2 months & other group is treated with conventional physiotherapy for 5 days in a week for 2 months. The objectives were tested by using tremor rating scale and nine hole peg test. The values are collected before and after the treatment Results: In the group treated with wrist weighing the improvement in the tremor rating scale is very significant (p: 0.0001 and in nine hole peg test is extremely significant (p: 0.0001. In conventional therapy group the improvement in the tremor rating scale is not significant (p: 0.0051 and in nine hole peg test is very significant (p: 0.0002. Conclusion: Incorporation of wrist weighing along with conventional therapy reduced the intensity of upper limb tremors in patients with cerebellar injuries but both the treatments are effective in improving upper limb functions. KEY WORDS: Intentional tremor, Rehabilitation, Wrist weighing

  8. Beta-adrenergic modulation of tremor and corticomuscular coherence in humans.

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    Mark R Baker

    Full Text Available Coherence between the bioelectric activity of sensorimotor cortex and contralateral muscles can be observed around 20 Hz. By contrast, physiological tremor has a dominant frequency around 10 Hz. Although tremor has multiple sources, it is partly central in origin, reflecting a component of motoneuron discharge at this frequency. The motoneuron response to ~20 Hz descending input could be altered by non-linear interactions with ~10 Hz motoneuron firing. We investigated this further in eight healthy human subjects by testing the effects of the beta-adrenergic agents propranolol (non-selective β-antagonist and salbutamol (β(2-agonist, which are known to alter the size of physiological tremor. Corticomuscular coherence was assessed during an auxotonic precision grip task; tremor was quantified using accelerometry during index finger extension. Experiments with propranolol used a double-blind, placebo-controlled crossover design. A single oral dose of propranolol (40 mg significantly increased beta band (15.3-32.2 Hz corticomuscular coherence compared with placebo, but reduced tremor in the 6.2-11.9 Hz range. Salbutamol (2.5 mg was administered by inhalation. Whilst salbutamol significantly increased tremor amplitude as expected, it did not change corticomuscular coherence. The opposite direction of the effects of propranolol on corticomuscular coherence and tremor, and the fact that salbutamol enhances tremor but does not affect coherence, implies that the magnitude of corticomuscular coherence is little influenced by non-linear interactions with 10 Hz oscillations in motoneurons or the periphery. Instead, we suggest that propranolol and salbutamol may affect both tremor and corticomuscular coherence partly via a central site of action.

  9. Observations of volcanic earthquakes and tremor at Deception Island - Antarctica

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    J. Morales

    1999-06-01

    Full Text Available Deception Island - South Shetlands, Antarctica is site of active volcanism. Since 1988 field surveys have been carried out with the aim of seismic monitoring, and in 1994 a seismic array was set up near the site of the Spanish summer base in order to better constrain the source location and spectral properties of the seismic events related to the volcanic activity. The array was maintained during the Antarctic summer of 1995 and the last field survey was carried out in 1996. Data show the existence of three different groups (or families of seismic events: 1 long period events, with a quasi-monochromatic spectral content (1-3 Hz peak frequency and a duration of more than 50 s, often occurring in small swarms lasting from several minutes to some day; 2 volcanic tremor, with a spectral shape similar to the long period events but with a duration of several minutes (2-10; 3 hybrid events, with a waveform characterised by the presence of a high frequency initial phase, followed by a low frequency phase with characteristics similar to those of the long period events. The high frequency phase of the hybrid events was analysed using polarisation techniques, showing the presence of P waves. This phase is presumably located at short epicentral distances and shallow source depth. All the analysed seismic events show back-azimuths between 120 and 330 degrees from north (corresponding to zones of volcanic activity showing no seismic activity in the middle of the caldera. Particle motion, Fourier spectral and spectrogram analysis show that the low frequency part of the three groups of the seismic signals have similar patterns. Moreover careful observations show that the high frequency phase which characterises the hybrid events is present in the long period and in the tremor events, even with lower signal to noise ratios. This evidence suggests that long period events are events in which the high frequency part is simply difficult to observe, due to a very

  10. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

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    D. Seidl

    1999-06-01

    Full Text Available Among a variety of spectrogram methods Short-Time Fourier Transform (STFT and Continuous Wavelet Transform (CWT were selected to analyse transients in non-stationary tremor signals. Depending on the properties of the tremor signal a more suitable representation of the signal is gained by CWT. Three selected broadband tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli.

  11. Feasibility study of spectral pattern recognition reveals distinct classes of volcanic tremor

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    Unglert, K.; Jellinek, A. M.

    2017-04-01

    Systematic investigations of the similarities and differences among volcanic tremor at a range of volcano types may hold crucial information about the plausibility of inferred source mechanisms, which, in turn, may be important for eruption forecasting. However, such studies are rare, in part because of an intrinsic difficulty with identifying tremor signals within very long time series of volcano seismic data. Accordingly, we develop an efficient tremor detection algorithm and identify over 12,000h of volcanic tremor on 24 stations at Kīlauea, Okmok, Pavlof, and Redoubt volcanoes. We estimate spectral content over 5-minute tremor windows, and apply a novel combination of Principal Component Analysis (PCA) and hierarchical clustering to identify patterns in the tremor spectra. Analyzing several stations from a given volcano together reveals different styles of tremor within individual volcanic settings. In addition to identifying tremor properties common to all stations in a given network, we find localized tremor signals including those related to processes such as lahars or dike intrusions that are only observed on some of the stations within a network. Subsequent application of our analysis to a combination of stations from the different volcanoes reveals that at least three main tremor classes can be detected across all settings. Whereas a regime with a ridge of high power distributed over 1-2Hz and a gradual decay of spectral power towards higher frequencies is observed dominantly at three volcanoes (Kīlauea, Okmok, Redoubt) with magma reservoirs centered at less than 5km below sea level (b.s.l.), a spectrum with a steeper slope and a narrower peak at 1-2Hz is observed only in association with open vents (Kīlauea and Pavlof). A third regime with a peak at approximately 3Hz is confined to two stratovolcanoes (Pavlof and Redoubt). These observations suggest generic relationships between the spectral character of the observed signals and volcano

  12. Sweet Spot Tremor Triggered by Intraslab Earthquakes in the Nankai Subduction Zone

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    Aiken, C.; Obara, K.; Peng, Z.; Chao, K.; Maeda, T.

    2014-12-01

    Deep tectonic tremor has been observed at several major plate-bounding faults around the Pacific Rim. Tremor­ in these regions can be triggered by small stresses arising from solid earth tides as well as passing seismic waves of large, distant earthquakes. While large, distant earthquakes are capable of repeatedly triggering tremor in the same region (i.e., a sweet spot), it is less understood how intraslab earthquakes interact with sweet spot tremor areas. We conduct a systematic survey of tremor triggered in the Nankai subduction zone by intraslab earthquakes to better understand what governs fault slip along the Eurasian-Philippine Sea Plate boundary. We examine 3 tremor sweet spots in the Nankai subduction zone: Shikoku West, Kii North, and Tokai. In each region, we select earthquakes from the Japan Meteorological Agency (JMA) catalog that occur from mid-2009 to mid-2014 with magnitude (M) greater than 2, that occur within the down-going Philippine Sea Plate, and within a 300 km epicentral distance of the sweet spot region. Using these selection criteria, we obtain ~1,200 earthquakes in each region. We examine a tremor catalog immediately before and after these local events as well as visually inspect filtered waveforms from short-period Hi-net seismic stations surrounding the sweet spot areas to identify additional tremor signals. From our initial analysis, we have identified 18 clear cases of increased tremor activity immediately following intraslab earthquakes in Shikoku West, most of which occur down-dip of the Shikoku West sweet spot. In comparison, we have identified only 5 triggering earthquakes in Kii North, and our investigation at Tokai is still ongoing. Our results so far are in agreement with triggering susceptibility being dependent upon background activity rates, as has been suggested for remote triggering of microearthquakes in geothermal regions by large, distant earthquakes as well as for remotely triggered tremor in the Nankai subduction zone

  13. Complex behavior and source model of the tremor at Arenal volcano, Costa Rica

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    Lesage, Philippe; Mora, Mauricio M.; Alvarado, Guillermo E.; Pacheco, Javier; Métaxian, Jean-Philippe

    2006-09-01

    Typical records of volcanic tremor and explosion quakes at Arenal volcano are analyzed with a high-resolution time-frequency method. The main characteristics of these seismic signals are: (1) numerous regularly spaced spectral peaks including both odd and even overtones; (2) frequency gliding in the range [0.9-2] Hz of the fundamental peak; (3) frequency jumps with either positive or negative increments; (4) tremor episodes with two simultaneous systems of spectral peaks affected by independent frequency gliding; (5) progressive transitions between spasmodic tremor and harmonic tremor; (6) lack of clear and systematic relationship between the occurrence of explosions and tremor. Some examples of alternation between two states of oscillation characterized by different fundamental frequencies are also observed. Some tremor and explosion codas are characterized by acoustic and seismic waves with identical spectral content and frequency gliding, which suggests a common excitation process. We propose a source model for the tremor at Arenal in which intermittent gas flow through fractures produces repetitive pressure pulses. The repeating period of the pulses is stabilized by a feedback mechanism associated with standing or traveling waves in the magmatic conduit. The pressure pulses generate acoustic waves in the atmosphere and act as excitation of the interface waves in the conduit. When the repeating period of the pulses is stable enough, they produce regularly spaced spectral peaks by the Dirac comb effect and hence harmonic tremor. When the period stability is lost, because of failures in the feedback mechanism, the tremor becomes spasmodic. The proposed source model of tremor is similar to the sound emission process of a clarinet. Fractures in the solid or viscous layer capping the lava pool in the crater act as the clarinet reed, and the conduit filled with low velocity bubbly magma is equivalent to the pipe of the musical instrument. The frequency gliding is

  14. Holmes tremor in association with bilateral hypertrophic olivary degeneration and palatal tremor: chronological considerations. Case report Tremor de Holmes em associação com degeneração olivar hipertrófica bilateral e tremor palatal: considerações cronológicas. Relato de caso

    Directory of Open Access Journals (Sweden)

    Carlos R.M. Rieder

    2003-06-01

    Full Text Available Hypertrophic olivary degeneration (HOD is a rare type of neuronal degeneration involving the dento-rubro-olivary pathway and presents clinically as palatal tremor. We present a 48 year old male patient who developed Holmes' tremor and bilateral HOD five months after brainstem hemorrhage. The severe rest tremor was refractory to pharmacotherapy and botulinum toxin injections, but was markedly reduced after thalamotomy. Magnetic resonance imaging permitted visualization of HOD, which appeared as a characteristic high signal intensity in the inferior olivary nuclei on T2- and proton-density-weighted images. Enlargement of the inferior olivary nuclei was also noted. Palatal tremor was absent in that moment and appears about two months later. The delayed-onset between insult and tremor following structural lesions of the brain suggest that compensatory or secondary changes in nervous system function must contribute to tremor genesis. The literature and imaging findings of this uncommon condition are reviewed.Degeneração olivar hipertrófica (DOH é um tipo raro de degeneração neuronal envolvendo o trato dento-rubro-olivar e se apresenta clinicamente como tremor palatal. Relatamos o caso de um homem de 48 anos que desenvolveu tremor de Holmes e DOH bilateral cinco meses após hemorragia em tronco encefálico. O intenso tremor de repouso foi refratário a farmacoterapia e injeções de toxina botulínica, mas foi enormemente reduzido após talamotomia. Ressonância magnética permitiu a visualização da DOH, que apareceu como um sinal intenso característico na oliva inferior em imagens ponderadas em T2 e densidade de prótons. Aumento do complexo olivar inferior também foi percebido. O tremor palatal era ausente naquele momento e apareceu cerca de dois meses depois. O início tardio do tremor após a lesão estrutural sugere que alterações compensatórias ou secundárias no sistema nervoso devem contribuir para a gênese do tremor. A

  15. Head Start.

    Science.gov (United States)

    Greenman, Geri

    2000-01-01

    Discusses an art project in which students created drawings of mop heads. Explains that the approach of drawing was more important than the subject. States that the students used the chiaroscuro technique, used by Rembrandt and Caravaggio, in which light appears out of the darkness. (CMK)

  16. Familial Essential Tremor Studied With Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Hernandez, A.; Salgado, P.; Gil, A.; Barrios, F. A.

    2003-09-01

    Functional Magnetic Resonance Imaging has become an important analytical tool to study neurodegenerative diseases. We applied the EPI-BOLD functional Magnetic Resonance Imaging technique to acquire functional images of patients with familial essential tremor (FET) disorder and healthy control volunteers, during a motor task activity. Functional and anatomic images were used to produce the brain activation maps of the patients and volunteers. These functional maps of the primary somatosensorial and motor cortexes of patients and control subjects were compared for functional differences per subject. The averaged functional brain images of eight of each case were acquired were, it can be clearly observed the differences in active zones. The results presented in this work show that there are differences in the functional maps during motor task activation between control subjects and FET patients suggesting a cerebral functional reorganization that can be mapped with BOLD-fMRI.

  17. Infantile tremor syndrome: Role of Vitamin B12 revisited

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    Rajesh Gupta

    2016-01-01

    Full Text Available Objective: To study the role of Vitamin B12 as an etiological factor in patients of infantile tremor syndrome (ITS. Methods: Twelve consecutive admissions of children diagnosed clinically as ITS were assessed. Assessment was done using a predefined pro forma to document patient demographic factors, general examination, systemic examination as well as relevant hematological and biochemical investigations. Results: Out of the 12 cases of ITS, 6 were males and 6 were females. Two cases had serum B12 levels below reference values, five had levels in low normal range, and remaining five had normal values. Conclusions: Role of Vitamin B12 deficiency as an etiological factor in the patients of ITS is inconclusive.

  18. Report on the Aseismic Slip, Tremor, and Earthquakes Workshop

    Science.gov (United States)

    Gomberg, Joan; Roeloffs, Evelyn; Trehu, Anne; Dragert, Herb; Meertens, Charles

    2008-01-01

    This report summarizes the discussions and information presented during the workshop on Aseismic Slip, Tremor, and Earthquakes. Workshop goals included improving coordination among those involved in conducting research related to these phenomena, assessing the implications for earthquake hazard assessment, and identifying ways to capitalize on the education and outreach opportunities presented by these phenomena. Research activities of focus included making, disseminating, and analyzing relevant measurements; the relationships among tremor, aseismic or 'slow-slip', and earthquakes; and discovering the underlying causative physical processes. More than 52 participants contributed to the workshop, held February 25-28, 2008 in Sidney, British Columbia. The workshop was sponsored by the U.S. Geological Survey, the National Science Foundation?s Earthscope Program and UNAVCO Consortium, and the Geological Survey of Canada. This report has five parts. In the first part, we integrate the information exchanged at the workshop as it relates to advancing our understanding of earthquake generation and hazard. In the second part, we summarize the ideas and concerns discussed in workshop working groups on Opportunities for Education and Outreach, Data and Instrumentation, User and Public Needs, and Research Coordination. The third part presents summaries of the oral presentations. The oral presentations are grouped as they were at the workshop in the categories of phenomenology, underlying physical processes, and implications for earthquake hazards. The fourth part contains the meeting program and the fifth part lists the workshop participants. References noted in parentheses refer to the authors of presentations made at the workshop, and published references are noted in square brackets and listed in the Reference section. Appendix A contains abstracts of all participant presentations and posters, which also have been posted online, along with presentations and author contact

  19. Treatment of essential tremor: Are there issues we are overlooking?

    Directory of Open Access Journals (Sweden)

    Elan D Louis

    2012-01-01

    Full Text Available Background: Essential tremor (ET is one of the most common neurological diseases. Although a large number of medications have been tested, there are only two first-line medications, primidone and propranolol, which is a situation that has not changed in approximately 30 years. Several recent reviews have summarized the current pharmacotherapeutic options for ET and the approach to the management of ET patients. Yet there remain a number of important issues, both scientific and clinical, that have not been broached in the literature and that have therapeutic implications. Objectives: To introduce several clinical and scientific issues that have not formally entered the published literature on the treatment of ET. Methods: In September 2011, materials for this article were gathered during a literature search of PubMed using the following terms: essential tremor, clinical, clinical trial, treatment, medications, therapeutics. English-language articles were selected for further review.Results: The paper focuses on several topics that have received scant or no discussion in the published literature on ET therapeutics. These topics are as follows: the nature of the underlying disease pathophysiology, the presence of pathological heterogeneity, the complexity of cellular and neurochemical changes which may be underlying this disorder, the presence of clinical heterogeneity, the selection of treatment endpoints, the effects of diagnostic uncertainty, the presence of cognitive and psychiatric features in ET, the identification of possible modifiable risk factors and the absence of any neuroprotective therapies. Conclusions: The author has identified several topics that have received scant or no discussion in the published literature on ET therapeutics. Further discussion of the issues raised here may lead to improvements in clinical trial methodologies as well as facilitate the development of fresh approaches to pharmacotherapy.

  20. An Unusual Presentation of Vertigo: Is Head Titubation the Key to Diagnosis?

    Directory of Open Access Journals (Sweden)

    O. Judd

    2009-01-01

    Full Text Available Objective. Discuss complex interplay of pathophysiological effects of cerebellar space occupying lesions on the vestibular pathway. Discuss challenges of diagnosis and referral along with differential and final diagnosis of unusual presentation. Case Report. We describe the case of a patient with vertiginous symptoms complicated by neurological features, namely, head titubation and tremor. The patient also had signs of oscillopsia and possible impairment of the vestibulo-ocular reflex. The resulting symptom and sign complex made for a difficult diagnosis, as the interplay of the pathophysiology of these signs, were unusual. Conclusion. The discussion has revealed that the cerebellar lesions themselves may have simultaneously caused head tremor and an inability for the vestibulo-ocular reflex to compensate, resulting in vertigo. However, whether the vertigo was a result of an oscillopsia, nystagmus, or central cause, the referral route should initially be via a general physician to rule out such a life threatening cause as a tumour.

  1. Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault

    Science.gov (United States)

    Shelly, David R.; Hardebeck, Jeanne L.

    2010-01-01

    We precisely locate 88 tremor families along the central San Andreas Fault using a 3D velocity model and numerous P and S wave arrival times estimated from seismogram stacks of up to 400 events per tremor family. Maximum tremor amplitudes vary along the fault by at least a factor of 7, with by far the strongest sources along a 25 km section of the fault southeast of Parkfield. We also identify many weaker tremor families, which have largely escaped prior detection. Together, these sources extend 150 km along the fault, beneath creeping, transitional, and locked sections of the upper crustal fault. Depths are mostly between 18 and 28 km, in the lower crust. Epicenters are concentrated within 3 km of the surface trace, implying a nearly vertical fault. A prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6.0 Parkfield earthquake.

  2. Tremor suppression using functional electrical stimulation: a comparison between digital and analog controllers.

    Science.gov (United States)

    Gillard, D M; Cameron, T; Prochazka, A; Gauthier, M J

    1999-09-01

    In this study, we compared digital and analog versions of a functional electrical stimulator designed to suppress tremor. The device was based on a closed-loop control system designed to attenuate movements in the tremor frequency range, without significantly affecting slower, voluntary movements. Testing of the digital filter was done on three patients with Parkinsonian tremor and the results compared to those of a functional electrical stimulation device based on an analog filter evaluated in a previous study. Additional testing of both the analog and digital filters was done on three subjects with no neurological impairment performing tremor-like movements and slow voluntary movements. We found that the digital controller provided a mean attenuation of 84%, compared to 65% for the analog controller.

  3. Cascadia tremor located near plate interface constrained by S minus P wave times.

    Science.gov (United States)

    La Rocca, Mario; Creager, Kenneth C; Galluzzo, Danilo; Malone, Steve; Vidale, John E; Sweet, Justin R; Wech, Aaron G

    2009-01-30

    Nonvolcanic tremor is difficult to locate because it does not produce impulsive phases identifiable across a seismic network. An alternative approach to identifying specific phases is to measure the lag between the S and P waves. We cross-correlate vertical and horizontal seismograms to reveal signals common to both, but with the horizontal delayed with respect to the vertical. This lagged correlation represents the time interval between vertical compressional waves and horizontal shear waves. Measurements of this interval, combined with location techniques, resolve the depth of tremor sources within +/-2 kilometers. For recent Cascadia tremor, the sources locate near or on the subducting slab interface. Strong correlations and steady S-P time differences imply that tremor consists of radiation from repeating sources.

  4. Cannabinoids and Tremor Induced by Motor-related Disorders: Friend or Foe?

    Science.gov (United States)

    Arjmand, Shokouh; Vaziri, Zohreh; Behzadi, Mina; Abbassian, Hassan; Stephens, Gary J; Shabani, Mohammad

    2015-10-01

    Tremor arises from an involuntary, rhythmic muscle contraction/relaxation cycle and is a common disabling symptom of many motor-related diseases such as Parkinson disease, multiple sclerosis, Huntington disease, and forms of ataxia. In the wake of anecdotal, largely uncontrolled, observations claiming the amelioration of some symptoms among cannabis smokers, and the high density of cannabinoid receptors in the areas responsible for motor function, including basal ganglia and cerebellum, many researchers have pursued the question of whether cannabinoid-based compounds could be used therapeutically to alleviate tremor associated with central nervous system diseases. In this review, we focus on possible effects of cannabinoid-based medicines, in particular on Parkinsonian and multiple sclerosis-related tremors and the common probable molecular mechanisms. While, at present, inconclusive results have been obtained, future investigations should extend preclinical studies with different cannabinoids to controlled clinical trials to determine potential benefits in tremor.

  5. Levetiracetam in primary orthostatic tremor: a double-blind placebo-controlled crossover study.

    Science.gov (United States)

    Hellriegel, Helge; Raethjen, Jan; Deuschl, G; Volkmann, Jens

    2011-11-01

    In a double-blind crossover study we evaluated the antitremor effect of a 4-week treatment with either escalating dosages of levetiracetam or placebo in orthostatic tremor. Twelve patients with orthostatic tremor participated in the study. Primary end point was improvement in stance duration. Secondary end points were total track length of the sway path and tremor total power. The patients' impression of impairment was assessed by a visual analog scale and quality of life by the SF-36. We found no significant effect of dosage or treatment on stance duration (P = .175), total track length (P = .690), total power (P = .280), or visual analog scale (P =.735). Neither was SF-36 differentially changed by levetiracetam or placebo (SF-36, Physical Component Summary: P = .079; SF-36, Mental Component Summary: P = .073). Side effects like dizziness, fatigue, or nausea were only mild to moderate. Levetiracetam is ineffective in the treatment of orthostatic tremor. Copyright © 2011 Movement Disorder Society.

  6. Geophysics. Migrating tremor off southern Kyushu as evidence for slow slip of a shallow subduction interface.

    Science.gov (United States)

    Yamashita, Y; Yakiwara, H; Asano, Y; Shimizu, H; Uchida, K; Hirano, S; Umakoshi, K; Miyamachi, H; Nakamoto, M; Fukui, M; Kamizono, M; Kanehara, H; Yamada, T; Shinohara, M; Obara, K

    2015-05-08

    Detection of shallow slow earthquakes offers insight into the near-trench part of the subduction interface, an important region in the development of great earthquake ruptures and tsunami generation. Ocean-bottom monitoring of offshore seismicity off southern Kyushu, Japan, recorded a complete episode of low-frequency tremor, lasting for 1 month, that was associated with very-low-frequency earthquake (VLFE) activity in the shallow plate interface. The shallow tremor episode exhibited two migration modes reminiscent of deep tremor down-dip of the seismogenic zone in some other subduction zones: a large-scale slower propagation mode and a rapid reversal mode. These similarities in migration properties and the association with VLFEs strongly suggest that both the shallow and deep tremor and VLFE may be triggered by the migration of episodic slow slip events.

  7. Implementation of an iPhone for characterizing Parkinson's disease tremor through a wireless accelerometer application.

    Science.gov (United States)

    Lemoyne, Robert; Mastroianni, Timothy; Cozza, Michael; Coroian, Cristian; Grundfest, Warren

    2010-01-01

    Parkinson's disease represents a chronic movement disorder, which is generally proportionally to age. The status of Parkinson's disease is traditionally classified through ordinal scale strategies, such as the Unified Parkinson's Disease Rating Scale. However, the application of the ordinal scale strategy inherently requires highly specialized and limited medical resources for interpretation. An alternative strategy involves the implementation of an iPhone application that enables the device to serve as a functional wireless accelerometer system. The Parkinson's disease tremor attributes may be recorded in either an effectively autonomous public or private setting, for which the resultant accelerometer signal of the tremor can be conveyed wireless and through email to a remote location for data post-processing. The initial testing and evaluation of the iPhone wireless accelerometer application for quantifying Parkinson's disease tremor successfully demonstrates the capacity to acquire tremor characteristics in an effectively autonomous environment, while potentially alleviating strain on limited and highly specialized medical resources.

  8. Effect of midazolam versus propofol sedation on markers of neurological injury and outcome after isolated severe head injury: a pilot study.

    LENUS (Irish Health Repository)

    Ghori, Kamran A

    2012-02-03

    BACKGROUND: Midazolam and propofol are sedative agents commonly administered to patients with brain injury. We compared plasma concentrations of glial cell S100beta protein and nitric oxide (NO) between patients who received midazolam and those who received propofol sedation after severe brain injury, and investigated the association between S100beta and NO concentrations and neurological outcome. DESIGN: 28 patients with severe head injury (Glasgow Coma Score <9) who required sedation and ventilation were randomly assigned to receive midazolam (n =15) or propofol (n = 13) based sedation. Blood samples were drawn daily for 5 days for estimation of S100beta and NO concentrations. Neurological outcome was assessed 3 months later as good (Glasgow Outcome Score [GOS], 4-5) or poor (GOS, 1-3). RESULTS: A good neurological outcome was observed in 8\\/15 patients (53%) in the midazolam group and 7\\/13 patients (54%) in the propofol group. Patients with a poor outcome had higher serum S100beta concentrations on ICU admission and on Days 1-4 in the ICU than those with a good outcome (mean [SD] on Day 1, 0.99 [0.81] v 0.41 [0.4] microg\\/L; Day 2, 0.80 [0.81] v 0.41 [0.24] microg\\/L; Day 3, 0.52 [0.55] v 0.24 [0.25] microg\\/L; and Day 4, 0.54 [0.43] v 0.24 [0.35] microg\\/L; P<0.05). There was no significant difference on Day 5. Plasma NO concentrations were not associated with outcome. In subgroup analysis, there was no difference in S100beta and NO concentrations between patients with a good outcome versus those with a poor outcome in either the midazolam or propofol group. CONCLUSIONS: Plasma concentrations of markers of neurological injury in patients with severe head injury were similar in those who received midazolam sedation and those who received propofol. Patients who had a poor neurological outcome at 3 months had consistently higher serum S100beta concentrations during the initial 4 days after injury than patients who had a good outcome.

  9. Detailed Tremor Migration Styles in Guerrero, Mexico Imaged with Cross-station Cross-correlations

    Science.gov (United States)

    Peng, Y.; Rubin, A. M.

    2015-12-01

    Tremor occurred downdip of the area that slipped the most during the 2006 slow slip event (SSE) in Guerrero, Mexico, as opposed to Cascadia, where tremor locations and rupture zones of SSEs largely overlap. Here we obtain high resolution tremor locations by applying cross-station cross-correlations [Armbruster et al., 2014] to seismic data from the Meso-America Subduction Experiment deployment. A few 3-station detectors are adopted to capture detailed deformation styles in the tremor "transient zone" and the downdip "sweet spot" as defined in Frank et al., 2014. Similar to Cascadia, tremor activities in our study region were comprised mostly of short tremor bursts lasting minutes to hours. Many of these bursts show clear migration patterns with propagation velocities of hundreds of km/day, comparable to those in Cascadia. However, the propagation of the main tremor front was often not in a simple unilateral fashion. Before the 2006 SSE, we observe 4 large tremor episodes during which both the transient zone and the sweet spot participated, consistent with previous findings [Frank et al., 2014]. The transient zone usually became active a few days after the sweet spot. We find many along-dip migrations with recurrence intervals of about a half day within a region about 10 km along strike and 35 km along dip in the sweet spot, suggesting possible tidal modulation, after the main front moved beyond this region. These migrations appear not to originate at the main front, in contrast to tremor migrations from a few km to tens of km across observed in Cascadia [Rubin and Armbruster, 2013; Peng et al., 2015; Peng and Rubin, submitted], but possibly similar to Shikoku, Japan [Shelly et al., 2007]. We do not observe obvious half-day periodicity for the migrations farther downdip within the sweet spot. During the SSE, the recurrence interval of tremor episodes decreased significantly in both the transient zone and the sweet spot, with that of the former being much shorter

  10. Volcanic tremors and magma wagging: gas flux interactions and forcing mechanism

    Science.gov (United States)

    Bercovici, David; Jellinek, A. Mark; Michaut, Chloé; Roman, Diana C.; Morse, Robert

    2013-11-01

    Volcanic tremor is an important precursor to explosive eruptions and is ubiquitous across most silicic volcanic systems. Oscillations can persist for days and occur in a remarkably narrow frequency band (i.e. 0.5-7 Hz). The recently proposed magma-wagging model of Jellinek & Bercovici provides a basic explanation for the emergence and frequency evolution of tremor that is consistent with observations of many active silicic and andesitic volcanic systems. This model builds on work suggesting that the magma column rising in the volcanic conduit is surrounded by a permeable vesicular annulus of sheared bubbles. The magma-wagging model stipulates that the magma column rattles within the spring like foam of the annulus, and predicts oscillations at the range of observed tremor frequencies for a wide variety of volcanic environments. However, the viscous resistance of the magma column attenuates the oscillations and thus a forcing mechanism is required. Here we provide further development of the magma-wagging model and demonstrate that it implicitly has the requisite forcing to excite wagging behaviour. In particular, the extended model allows for gas flux through the annulus, which interacts with the wagging displacements and induces a Bernoulli effect that amplifies the oscillations. This effect leads to an instability involving growing oscillations at the lower end of the tremor frequency spectrum, and that drives the system against viscous damping of the wagging magma column. The fully non-linear model displays tremor oscillations associated with pulses in gas flux, analogous to observations of audible `chugging'. These oscillations also occur in clusters or envelopes that are consistent with observations of sporadic tremor envelopes. The wagging model further accurately predicts that seismic signals on opposite sides of a volcano are out of phase by approximately half a wagging or tremor period. Finally, peaks in gas flux occur at the end of the growing instability

  11. Recent Findings on the Nature of Episodic Tremor and Slip Along the Northern Cascadia Margin

    Science.gov (United States)

    Dragert, H.; Wang, K.; Kao, H.

    2008-12-01

    Episodic Tremor and Slip (ETS), as observed along the northern Cascadia margin, has been defined empirically as repeated, transient ground motions at a plate margin, roughly opposite to longer-term interseismic deformation, occurring synchronously with low-frequency, emergent seismic signals. Although the exact causal processes are still a matter of debate, recent improvements in the monitoring of these transient events provide clearer constraints for the location and the migration of both tremor and slip. In areal distribution, the tremors continue to occur in a band overlying the 25 to 55 km depth contours of the nominal subducting plate interface. The previously reported extended depth distribution of tremor is also observed for the most recent tremor episodes, as is the coincidence of peak tremor activity with a band of seismic reflectors that is commonly interpreted to be positioned above the plate interface. In these episodes, tremors migrate along strike of the subduction zone from the southeast to the northwest at speeds ranging from 5 to 13 km/day. Tremor data also show changes in migration speed during the course of a single episode. No systematic migration in depth has yet been resolved. Denser GPS monitoring and the introduction of borehole strainmeters have also led to a better definition of the ETS surface deformations patterns, including those derived from the vertical GPS component. Inversion of the GPS data, constrained by limiting slip to the currently accepted plate interface, results in an area of slip that parallels the strike of the subduction zone, overlapping with but narrower than the band of tremor distribution and displaced slightly seaward. Inversion constrained by a shallower occurrence of slip, on or near the reflector band, results in a broader distribution of slip with reduced magnitudes. This would be more commensurate with the wider distribution of tremor. The current GPS deformation data are unable to tell whether the slip could

  12. Using a Smart Phone as a Standalone Platform for Detection and Monitoring of Pathological Tremors

    OpenAIRE

    Daneault, Jean-François; Carignan, Benoit; Codère, Carl Éric; Abbas F Sadikot; Duval, Christian

    2013-01-01

    Introduction: Smart phones are becoming ubiquitous and their computing capabilities are ever increasing. Consequently, more attention is geared toward their potential use in research and medical settings. For instance, their built-in hardware can provide quantitative data for different movements. Therefore, the goal of the current study was to evaluate the capabilities of a standalone smart phone platform to characterize tremor. Results: Algorithms for tremor recording and online analysis can...

  13. How to tackle tremor – systematic review of the literature and diagnostic work-up

    Directory of Open Access Journals (Sweden)

    Arthur W.G. Buijink

    2012-10-01

    Full Text Available BackgroundTremor is the most prevalent movement disorder in clinical practice. It is defined as involuntary, rhythmic, oscillatory movements. The diagnostic process of patients with tremor can be laborious and challenging, and a clear, systematic overview of available diagnostic techniques is lacking. Tremor can be a symptom of many diseases, but can also represent a distinct disease entity.ObjectiveThe objective of this review is to give a clear, systematic and step-wise overview of the diagnostic work-up of a patient with tremor. The clinical relevance and value of available laboratory tests in patients with tremor will be explored.MethodsWe systematically searched through EMBASE. The retrieved articles were supplemented by articles containing relevant data or provided important background information. Studies that were included investigated the value and/or usability of diagnostic tests for tremor.ResultsIn most patients, history and clinical examination by an experienced movement disorders neurologist are sufficient to establish a correct diagnosis, and further ancillary examinations will not be needed. Ancillary investigation should always be guided by tremor type(s present and other associated signs and symptoms. The main ancillary examination techniques currently are electromyography and SPECT imaging. Unfortunately, many techniques have not been studied in large prospective, diagnostic studies to be able to determine important variables like sensitivity and specificity.ConclusionWhen encountering a patient with tremor, history and careful clinical examination should guide the diagnostic process. Adherence to the diagnostic work-up provided in this review will help the diagnostic process of these patients.

  14. Tidal sensitivity of tectonic tremors in Nankai and Cascadia subduction zones

    Science.gov (United States)

    Yabe, Suguru; Tanaka, Yoshiyuki; Houston, Heidi; Ide, Satoshi

    2015-11-01

    Tectonic tremors in subduction zones, which result from slip at the deep plate interface, are known to exhibit a 12.4 h periodicity in their activity, due to tidal influence. Because tidal stress can be calculated quantitatively, the response of the plate interface can yield quantitative information about its frictional property. The relation between tremor rate and tidal stress is investigated, and an exponential relation is widely confirmed, as observed by previous studies. This study particularly focuses on spatial variations of tidal sensitivity, which are compared with spatial variations of tremor duration and amplitude. The sensitivity is quantitatively defined by the exponent of the exponential relation, which can be related to the parameter aσ, or (a - b)σ in the rate-and-state friction law, where σ is effective normal stress. On the shallower tremor zone, short-duration and large-amplitude tremors occur followed by more sensitive tremors. Meanwhile, deeper tremors with longer duration and smaller amplitude show lower sensitivity, although along-strike variation also exists. Typical and maximum sensitivities estimated here imply values for aσ or (a - b)σ of about 3 and 1 kPa, respectively. These correlations are consistent with a model in which the plate interface consists of a velocity-strengthening background with embedded velocity-weakening regions. The frictional heterogeneity may be statistically characterized by cluster size and density of the velocity-weakening regions and controls the overall slip behavior. The observed depth dependency of tremor duration, amplitude, and sensitivity implies that frictional heterogeneity is controlled by physical quantities varying with depth, such as temperature or fluid amount.

  15. Iron accumulation and dysregulation in the putamen in fragile X-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Ariza, Jeanelle; Rogers, Hailee; Hartvigsen, Anna; Snell, Melissa; Dill, Michael; Judd, Derek; Hagerman, Paul; Martínez-Cerdeño, Verónica

    2017-04-01

    Fragile X-associated tremor/ataxia syndrome is an adult-onset disorder associated with premutation alleles of the FMR1 gene. This disorder is characterized by progressive action tremor, gait ataxia, and cognitive decline. Fragile X-associated tremor/ataxia syndrome pathology includes dystrophic white matter and intranuclear inclusions in neurons and astrocytes. We previously demonstrated that the transport of iron into the brain is altered in fragile X-associated tremor/ataxia syndrome; therefore, we also expect an alteration of iron metabolism in brain areas related to motor control. Iron is essential for cell metabolism, but uncomplexed iron leads to oxidative stress and contributes to the development of neurodegenerative diseases. We investigated a potential iron modification in the putamen - a structure that participates in motor learning and performance - in fragile X-associated tremor/ataxia syndrome. We used samples of putamen obtained from 9 fragile X-associated tremor/ataxia syndrome and 9 control cases to study iron localization using Perl's method, and iron-binding proteins using immunostaining. We found increased iron deposition in neuronal and glial cells in the putamen in fragile X-associated tremor/ataxia syndrome. We also found a generalized decrease in the amount of the iron-binding proteins transferrin and ceruloplasmin, and decreased number of neurons and glial cells that contained ceruloplasmin. However, we found increased levels of iron, transferrin, and ceruloplasmin in microglial cells, indicating an attempt by the immune system to remove the excess iron. Overall, found a deficit in proteins that eliminate extra iron from the cells with a concomitant increase in the deposit of cellular iron in the putamen in Fragile X-associated tremor/ataxia syndrome. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

  16. Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME: Probable first family from India

    Directory of Open Access Journals (Sweden)

    Chandra Mohan Sharma

    2014-01-01

    Full Text Available Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME is an extremely rare syndrome characterized by familial occurrence of postural and action-induced tremors of the hands but showing electrophysiologic findings of cortical reflex myoclonus. Patients also have cognitive decline and tonic-clonic seizures, often precipitated by sleep deprivation or photic stimulation. We describe probably the first family from India of this ill-defined syndrome.

  17. Changes of Physiological Tremor Following Maximum Intensity Exercise in Male and Female Young Swimmers

    Directory of Open Access Journals (Sweden)

    Gajewski Jan

    2015-12-01

    Full Text Available Purpose. The aim of this study was to determine the changes in postural physiological tremor following maximum intensity effort performed on arm ergometer by young male and female swimmers. Methods. Ten female and nine male young swimmers served as subjects in the study. Forearm tremor was measured accelerometrically in the sitting position before the 30-second Wingate Anaerobic Test on arm ergometer and then 5, 15 and 30 minutes post-test. Results. Low-frequency tremor log-amplitude (L1−5 increased (repeated factor: p < 0.05 from −7.92 ± 0.45 to −7.44 ± 0.45 and from −6.81 ± 0.52 to −6.35 ± 0.58 in women and men, respectively (gender: p < 0.05 5 minute post-test. Tremor log-amplitude (L15−20 increased (repeated factor: p < 0.001 from −9.26 ± 0.70 to −8.59 ± 0.61 and from −8.79 ± 0.65 to −8.39 ± 0.79 in women and men, respectively 5 minute post-test. No effect of gender was found for high frequency range.The increased tremor amplitude was observed even 30 minute post-exercise. Mean frequency of tremor spectra gradually decreased post-exercises (p < 0.001. Conclusions. Exercise-induced changes in tremor were similar in males and females. A fatigue produced a decrement in the mean frequency of tremor what suggested decreased muscle stiffness post-exercise. Such changes intremorafter exercise may be used as the indicator of fatigue in the nervous system.

  18. Surface-wave potential for triggering tectonic (nonvolcanic) tremor-corrected

    Science.gov (United States)

    Hill, David P.

    2012-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle are anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45° incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia megathrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction is μ* ≤ 0:2). Documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, however, are associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (μ ~ 0:6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  19. Northern Cascadia Episodic Tremor and Slip: A Decade of Observations from 1997 to 2007

    Science.gov (United States)

    Kao, H.; Shan, S.; Dragert, H.; Rogers, G.; Ito, Y.

    2008-12-01

    We analyze continuous seismic and GPS records collected in the last decade (1997-2007) to establish the most comprehensive observational basis for northern Cascadia episodic tremor and slip (ETS) events. A simple ¡§ETS scale¡¨ system, using a combination of a letter and a digit, is proposed to quantitatively characterize the spatial and temporal dimensions of ETS events. Clear correlation between GPS and tremor signals is observed for all major episodes with lateral dimension >150 km (i.e., A- or B-class), but the GPS signature is less obvious for minor ones. Regular ETS recurrence can be established only for A-/B-class episodes in southern Vancouver Island. Halting and jumping are very common in ETS migration patterns, and along-strike migration can happen in both directions. A prominent tremor gap is observed in mid island around 49.5N. This gap coincides with the epicenters of the only two large documented crustal earthquakes in the region. ETS tremors also tend to occur in places where the local seismicity is relatively sparse. The tremor depth distribution shows a peak in the 25-35 km range where strong seismic reflectors (i.e., the E- layer) are documented. Existence of tremors in the vicinity of E-layer is also confirmed by an independent waveform analysis. More significantly, we have found a few very-low-frequency earthquakes (VLFE) at the depth of E-layer showing low-angle thrust faulting mechanisms. Our results suggest that a significant portion of the tremor activity and perhaps associated shearing are taking place along well-developed structures such as the E-layer, while a reduced number of tremor bursts are generated elsewhere in response to induced stress variation throughout the source volume.

  20. Thalamic DBS with a constant-current device in essential tremor: A controlled clinical trial.

    Science.gov (United States)

    Wharen, Robert E; Okun, Michael S; Guthrie, Barton L; Uitti, Ryan J; Larson, Paul; Foote, Kelly; Walker, Harrison; Marshall, Frederick J; Schwalb, Jason; Ford, Blair; Jankovic, Joseph; Simpson, Richard; Dashtipour, Khashayar; Phibbs, Fenna; Neimat, Joseph S; Stewart, R Malcolm; Peichel, DeLea; Pahwa, Rajesh; Ostrem, Jill L

    2017-07-01

    This study of thalamic deep brain stimulation (DBS) investigated whether a novel constant-current device improves tremor and activities of daily living (ADL) in patients with essential tremor (ET). A prospective, controlled, multicenter study was conducted at 12 academic centers. We investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the ventralis intermedius (VIM) nucleus of the thalamus in patients with essential tremor whose tremor was inadequately controlled by medications. The primary outcome measure was a rater-blinded assessment of the change in the target limb tremor score in the stimulation-on versus stimulation-off state six months following surgery. Multiple secondary outcomes were assessed at one-year follow-up, including motor, mood, and quality-of-life measures. 127 patients were implanted with VIM DBS. The blinded, primary outcome variable (n = 76) revealed a mean improvement of 1.25 ± 1.26 points in the target limb tremor rating scale (TRS) score in the arm contralateral to DBS (p < 0.001). Secondary outcome variables at one year revealed significant improvements (p ≤ 0.001) in quality of life, depression symptoms, and ADL scores. Forty-seven patients had a second contralateral VIM-DBS, and this group demonstrated reduction in second-sided tremor at 180 days (p < 0.001). Serious adverse events related to the surgery included infection (n = 3), intracranial hemorrhage (n = 3), and device explantation (n = 3). Unilateral and bilateral constant-current VIM DBS significantly improves upper extremity tremor, ADL, quality of life, and depression in patients with severe ET. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A phase coherence approach to identifying co-located earthquakes and tremor

    Science.gov (United States)

    Hawthorne, J. C.; Ampuero, J.-P.

    2017-01-01

    We present and use a phase coherence approach to identify seismic signals that have similar path effects but different source time functions: co-located earthquakes and tremor. The method used is a phase coherence-based implementation of empirical matched field processing, modified to suit tremor analysis. It works by comparing the frequency-domain phases of waveforms generated by two sources recorded at multiple stations. We first cross-correlate the records of the two sources at a single station. If the sources are co-located, this cross-correlation eliminates the phases of the Green's function. It leaves the relative phases of the source time functions, which should be the same across all stations so long as the spatial extent of the sources are small compared with the seismic wavelength. We therefore search for cross-correlation phases that are consistent across stations as an indication of co-located sources. We also introduce a method to obtain relative locations between the two sources, based on back-projection of inter-station phase coherence. We apply this technique to analyze two tremor-like signals that are thought to be composed of a number of earthquakes. First, we analyze a 20-second-long seismic precursor to a M 3.9 earthquake in central Alaska. The analysis locates the precursor to within 2 km of the mainshock, and it identifies several bursts of energy-potentially foreshocks or groups of foreshocks-within the precursor. Second, we examine several minutes of volcanic tremor prior to an eruption at Redoubt Volcano. We confirm that the tremor source is located close to repeating earthquakes identified earlier in the tremor sequence. The amplitude of the tremor diminishes about 30 seconds before the eruption, but the phase coherence results suggest that the tremor may persist at some level through this final interval.

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  3. Methodology for estimating human perception to tremors in high-rise buildings

    Science.gov (United States)

    Du, Wenqi; Goh, Key Seng; Pan, Tso-Chien

    2016-12-01

    Human perception to tremors during earthquakes in high-rise buildings is usually associated with psychological discomfort such as fear and anxiety. This paper presents a methodology for estimating the level of perception to tremors for occupants living in high-rise buildings subjected to ground motion excitations. Unlike other approaches based on empirical or historical data, the proposed methodology performs a regression analysis using the analytical results of two generic models of 15 and 30 stories. The recorded ground motions in Singapore are collected and modified for structural response analyses. Simple predictive models are then developed to estimate the perception level to tremors based on a proposed ground motion intensity parameter—the average response spectrum intensity in the period range between 0.1 and 2.0 s. These models can be used to predict the percentage of occupants in high-rise buildings who may perceive the tremors at a given ground motion intensity. Furthermore, the models are validated with two recent tremor events reportedly felt in Singapore. It is found that the estimated results match reasonably well with the reports in the local newspapers and from the authorities. The proposed methodology is applicable to urban regions where people living in high-rise buildings might feel tremors during earthquakes.

  4. Dynamics of tremor-related oscillations in the human globus pallidus: A single case study

    Science.gov (United States)

    Hurtado, José M.; Gray, Charles M.; Tamas, Laszlo B.; Sigvardt, Karen A.

    1999-01-01

    Physiological evidence indicates that the resting tremor of Parkinson’s disease originates in oscillatory neural activity in the forebrain, but it is unknown whether that activity is globally synchronized or consists of parallel, independently oscillating circuits. In the present study, we used dual microelectrodes to record tremor-related neuronal activity from eight sites in the internal segment of the globus pallidus (GPi) from an awake Parkinson’s disease patient undergoing stereotaxic pallidotomy. We utilized spectral analysis to evaluate the temporal correlations between multiunit activity at spatially separated sites and between neural and limb electromyographic activity. We observed that some GPi neural pairs oscillated synchronously at the tremor frequency, whereas other neural pairs oscillated independently. Additionally, we found that GPi tremor-related activity at a given site could fluctuate between states of synchronization and independence with respect to upper limb tremor. Consistent with this finding, some paired recording sites within GPi showed periods of transient synchronization. These observations support the hypothesis of independent tremor-generating circuits whose coupling can fluctuate over time. PMID:9990083

  5. Analysis of fatigue and tremor during sustained maximal grip contractions using Hilbert-Huang Transformation.

    Science.gov (United States)

    Li, Ke; Hogrel, Jean-Yves; Duchêne, Jacques; Hewson, David J

    2012-09-01

    The objective of this study was to evaluate muscle fatigue and tremor during a Sustained Maximal Grip Contraction (SMGC) using the Hilbert-Huang Transformation (HHT). Thirty-nine healthy subjects volunteered for the study and performed a 25-s SMGC. Fatigue parameters such as the relative force output (RFO) were calculated from the residual of SMGC after applying Empirical Mode Decomposition (EMD). Using the energy spectrum of the Intrinsic Mode Functions (IMF) obtained using HHT, isometric force tremor was identified from the 4 to 12 Hz region in IMF3 and IMF4. Data were analysed for five consecutive 5-s epochs to identify changes in fatigue and tremor over time. The HHT method was able to identify a greater resistance to fatigue in women compared to men (p≤0.05) and in non-dominant hands compared to dominant hands (p≤0.05). Consistent with the results for fatigue, women had less tremor than men (p≤0.05), while non-dominant hands trembled less than did dominant hands (p≤0.05). Higher levels of tremor were observed for non-fatigue-resistant subjects for both 10-15 s and 15-20 s epochs (p≤0.05). The HHT is an appropriate method to identify both fatigue and tremor during SMGC. It would be of interest to apply this method to the study the elderly or patients with neuromuscular disorders.

  6. Quantification of a Secondary Task-Specific Tremor in a Violinist after a Temporal Lobectomy

    Directory of Open Access Journals (Sweden)

    André eLee

    2014-07-01

    Full Text Available Task-specific tremors occur mainly during certain tasks and may be highly disabling. In this case study, we report on a 66-year-old violinist who developed a task-specific tremor of the right arm only while playing the violin four weeks after a temporal lobectomy, which had been performed as a result of his temporal lobe epilepsy. Since a similar case, to our knowledge, has not been reported so far, our aim was to quantitatively assess and describe the tremor by measuring (a the electromyography (EMG activity of the wrist flexor and extensor as well as (b an accelerometer signal of the hand. We found a tremor-related frequency of about 7 Hz. Furthermore, at a similar frequency of about 7 Hz, there was coherence between the tremor acceleration and EMG-activity of the wrist flexor and extensor as well as between the tremor acceleration and coactivation. The tremorgenesis remains unclear, and possible explanations can only be speculative.

  7. Activation and tremor of the shoulder muscles to the demands of an archery task.

    Science.gov (United States)

    Lin, Jiu-Jenq; Hung, Cheng-Ju; Yang, Ching-Ching; Chen, Hsing-Yu; Chou, Feng-Ching; Lu, Tung-Wu

    2010-02-01

    Physiological tremor and strength during the maintenance of shoulder position occur during a precision aiming task, such as archery. It is unclear how positions for precision demands affect physiological tremor and associated muscular activities. The purpose of this study was to assess the tremor amplitude and muscular activities of the shoulder between the various positions for precision demands. Ten males (age 21.9 +/- 2.0 years) participated in the study. Electromyography (EMG) was quantified on eight humeral/scapular muscles. The tremor was measured by the acceleration component of a motion tracking sensor in the 3-7 Hz and 8-12 Hz frequency bands. Participants simulated six preparatory archery shooting positions (3 arm angles x 2 arm draw positions) and performed isometric contractions. The relative root mean square (RMS) amplitudes of the shoulder muscles were significantly greater for the full drawing position compared with the partial position (humeral muscles: P = 0.011; scapular muscles: P = 0.026). In the full drawing position, increased humeral/scapular muscle EMG amplitude was moderately associated with an increased power spectrum of 8-12/3-7 Hz tremor in humerus/scapula motion (R = 0.43-0.57). To minimize fluctuations in high strength muscle performance, 90 degrees of elevation in the full drawing position may be a suitable position for demands in archery. In addition, scapular muscle amplitude is important for stability to reduce humerus tremor during archery performance.

  8. Thyroid-Induced Worsening of Parkinsonian Tremor Resistant to Drugs and Subthalamic Nucleus Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Michal Minár

    2014-01-01

    Full Text Available Introduction. Symptoms of both hypothyroidism and thyrotoxicosis can be easily overlooked in patients with Parkinson’s disease (PD. We report on a patient whose parkinsonian tremor worsened and proved refractory not only to common treatment, but also to deep brain stimulation (DBS. Case Presentation. A 61-year-old woman with advanced PD underwent bilateral subthalamic DBS, with an excellent outcome. Twenty-one months after the surgery, however, patient’s resting/postural tremor markedly worsened. There was a slight improvement for 1 month after repeated adjustments of DBS parameters, but then the tremor worsened again. Since even a minimal increase of the dose of dopaminergic drugs caused extremely severe dyskinesias, an anticholinergic drug biperiden and benzodiazepine clonazepam were introduced, what helped for another month. With the onset of severe diarrhoea, a laboratory workup was performed. Thyrotoxicosis was detected. During treatment with the antithyroid agent carbimazole, the parkinsonian tremor clearly improved within two weeks. Conclusion. A hyperthyroid state can markedly exaggerate all forms of tremor, as well as other types of movement disorders. This condition can be overlooked or masked by other symptoms. Therefore, if the tremor in a patient with PD gradually worsens and proves resistant to the usual treatment, examine the thyroid gland.

  9. Methodology for estimating human perception to tremors in high-rise buildings

    Science.gov (United States)

    Du, Wenqi; Goh, Key Seng; Pan, Tso-Chien

    2017-07-01

    Human perception to tremors during earthquakes in high-rise buildings is usually associated with psychological discomfort such as fear and anxiety. This paper presents a methodology for estimating the level of perception to tremors for occupants living in high-rise buildings subjected to ground motion excitations. Unlike other approaches based on empirical or historical data, the proposed methodology performs a regression analysis using the analytical results of two generic models of 15 and 30 stories. The recorded ground motions in Singapore are collected and modified for structural response analyses. Simple predictive models are then developed to estimate the perception level to tremors based on a proposed ground motion intensity parameter—the average response spectrum intensity in the period range between 0.1 and 2.0 s. These models can be used to predict the percentage of occupants in high-rise buildings who may perceive the tremors at a given ground motion intensity. Furthermore, the models are validated with two recent tremor events reportedly felt in Singapore. It is found that the estimated results match reasonably well with the reports in the local newspapers and from the authorities. The proposed methodology is applicable to urban regions where people living in high-rise buildings might feel tremors during earthquakes.

  10. Effect of mental fatigue on induced tremor in human knee extensors.

    Science.gov (United States)

    Budini, Francesco; Lowery, Madeleine; Durbaba, Rade; De Vito, Giuseppe

    2014-06-01

    In this study, the effects of mental fatigue on mechanically induced tremor at both a low (3-6Hz) and high (8-12Hz) frequency were investigated. The two distinct tremor frequencies were evoked using two springs of different stiffness, during 20s sustained contractions of the knee extensor muscles at 30% maximum voluntary contraction (MVC) before and after 100min of a mental fatigue task, in 12 healthy (29±3.7years) participants. Mental fatigue resulted in a 6.9% decrease in MVC and in a 9.4% decrease in the amplitude of the agonist muscle EMG during sustained 30% MVC contractions in the induced high frequency only. Following the mental fatigue task, the coefficient of variation and standard deviation of the force signal decreased at 8-12Hz induced tremor by 31.7% and 35.2% respectively, but not at 3-6Hz induced tremor. Similarly, the maximum value and area underneath the peak in the power spectrum of the force signal decreased by 55.5% and 53.1% respectively in the 8-12Hz range only. In conclusion, mental fatigue decreased mechanically induced 8-12Hz tremor and had no effect on induced 3-6Hz tremor. We suggest that the reduction could be attributed to the decreased activation of the agonist muscles.

  11. Blunt Head Trauma and Headache

    Directory of Open Access Journals (Sweden)

    Ana B Chelse

    2015-04-01

    Full Text Available Investigators from New York Presbyterian Morgan Stanley Children’s Hospital examined whether having an isolated headache following minor blunt head trauma was suggestive of traumatic brain injury (TBI among a large cohort of children 2-18 years of age.

  12. Head Position and Internally Headed Relative Clauses.

    Science.gov (United States)

    Basilico, David

    1996-01-01

    Examines "Head Movement" in internally headed relative clauses (IHRCs). The article shows that in some cases, head movement to an external position need not take place and demonstrates that this movement of the head to a sentence-internal position results from the quantificational nature of IHRCs and Diesing's mapping hypothesis (1990, 1992). (56…

  13. Effect of Crocus sativus extracts and its active constituent safranal on the harmaline-induced tremor in mice

    Directory of Open Access Journals (Sweden)

    Bahareh Amin

    2015-05-01

    Full Text Available Objective(s: Due to unsatisfactory response or intolerable side effects of current drugs, treatment of essential tremor remains inadequate. Thus, we aimed to investigate the protective and therapeutic effects of aqueous and ethanolic extracts of Crocus sativus (saffron, and its active consistent, safranal, on the harmaline-induced tremor in mice. Materials and Methods: To induce tremor, harmaline (30 mg/kg was injected intraperitoneally. Test groups were also given the aqueous and ethanolic extracts of saffron (40, 80, and 160 mg/kg as well as safranal (0.1, 0.3, and 0.5 ml/kg, intraperitoneally, 10 min before harmaline administration (prophylactic study or 10 min after the onset of tremors (curative study. The latency of onset, duration, and intensity of tremor were recorded. Results: The extracts (80 and160 mg/kg dose dependently attenuated duration of harmaline-induced tremors as did reference drug, propranolol (2 and 5 mg/kg. Only the highest dose of extracts (160 mg/kg attenuated intensity of harmaline-induced tremors throughout the study. Safranal at the doses of (0.1 and 0.3 ml/kg but not 0.5 ml/kg attenuated duration and intensity of tremor. Onset of tremor increased with the extracts (80 and 160 mg/kg in prophylactic study, as the effect observed with propranolol at the dose of 5 mg/kg. Safranal did not affect the latency of tremor. Conclusion: Both aqueous and ethanolic extracts of saffron and with a less effect, low doses of safranal, have relatively protective and suppressive effects on the harmaline-induced tremor and different constituents of extracts seem to participate in the protective effects against harmaline induced tremor.

  14. Arm tremor and precision of hand force control in a short and long term flight on the Mir-Space-Station

    Science.gov (United States)

    Gallasch, E.; Kozlovskaya, I.; Löscher, W. N.; Konev, A.; Kenner, T.

    To determine whether long and short time exposure of man in 0g alters normal physiological tremor patterns we recorded arm tremor using an accelerometer as well as hand forces and tremor during constant isometric contraction using a load cell. Arm tremor was decreased during both flights in amplitude and frequency. Shortly after the long term flight arm tremor amplitude was increased, indicating adaptive changes in the tonic reflex loop. Isometric hand tremor remained unchanged during the long and short time flight demonstrating that the contractile properties of hand muscles remained constant. Precision of hand force was decreased until the half duration of the long term flight.

  15. Non-contact measurement of tremor for the characterisation of Parkinsonian individuals: comparison between Kinect and Laser Doppler vibrometer

    Science.gov (United States)

    Casacanditella, L.; Cosoli, G.; Ceravolo, MG; Tomasini, EP

    2017-08-01

    Parkinson’s disease is a progressive neurodegenerative disorder affecting the central nervous system. One of its main and most evident symptoms is the tremor, which usually manifests at rest with varying intensity during time. An important diagnostic challenge is the differential diagnosis between Parkinson’s disease and the other most widely represented tremor syndrome, i.e. Essential (or senile) tremor. At present there are no standard methods for the quantification of tremor and the diagnosis of both Parkinson’s disease and Essential tremor is mainly done on the base of clinical criteria and by using rating scales. The aim of this work is to objectively and non-invasively assess the tremor linked to the quoted diseases, using non-contact techniques: Laser Doppler Vibrometer (LDV) and Kinect for Windows device. Two subjects with Parkinson’s disease and one with Essential tremor were tested in different conditions: at rest, during a cognitive task, with forward stretched arms and in “Wing position”. The results from data processing in terms of tremor frequency seem to be comparable, with a mean deviation of 0.31 Hz. Furthermore, the values computed are consistent with what is stated in the literature (i.e. 4-12 Hz). So, both LDV and Kinect device can be considered suitable to be used as an objective means for the assessment and monitoring of Parkinson’s disease tremor, helping the clinician in the choice of the most suitable treatment for the patients.

  16. Cross-spectral analysis of physiological tremor and muscle activity; 1, Theory and application to unsynchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between the extensor electromyogram (EMG) and tremor time series in physiological hand tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and the effects of observational noise. We calculate the theoretical phase spectrum for a second order linear stochastic process and compare the results to measured tremor data recorded from subjects who did not show a synchronized EMG activity in the corresponding extensor muscle. The results show that physiological tremor is well described by the proposed model and that the measured EMG represents a Newtonian force by which the muscle acts on the hand.

  17. LINGO-1 and Neurodegeneration: Pathophysiologic Clues for Essential Tremor.

    Science.gov (United States)

    Zhou, Zhi-Dong; Sathiyamoorthy, Sushmitha; Tan, Eng-King

    2012-01-01

    Essential tremor (ET), one of the most common adult-onset movement disorders, has been associated with cerebellar Purkinje cell degeneration and formation of brainstem Lewy bodies. Recent findings suggest that genetic variants of the leucine-rich repeat and Ig domain containing 1 (LINGO-1) gene could be risk factors for ET. The LINGO-1 protein contains both leucine-rich repeat (LRR) and immunoglobulin (Ig)-like domains in its extracellular region, as well as a transmembrane domain and a short cytoplasmic tail. LINGO-1 can form a ternary complex with Nogo-66 receptor (NgR1) and p75. Binding of LINGO-1 with NgR1 can activate the NgR1 signaling pathway, leading to inhibition of oligodendrocyte differentiation and myelination in the central nervous system. LINGO-1 has also been found to bind with epidermal growth factor receptor (EGFR) and induce downregulation of the activity of EGFR-PI3K-Akt signaling, which might decrease Purkinje cell survival. Therefore, it is possible that genetic variants of LINGO-1, either alone or in combination with other genetic or environmental factors, act to increase LINGO-1 expression levels in Purkinje cells and confer a risk to Purkinje cell survival in the cerebellum.Here, we provide a concise summary of the link between LINGO-1 and neurodegeneration and discuss various hypotheses as to how this could be potentially relevant to ET pathogenesis.

  18. Transcranial sonography on Parkinson′s disease and essential tremor

    Directory of Open Access Journals (Sweden)

    Ahmad Chitsaz

    2013-01-01

    Full Text Available Background: The study on transcranial sonocraphy (TCS as a diagnostic test for Parkinson′s disease (PD has been neglected in some hospitals. The current study was conducted as the first study to investigate the utility of TCS for diagnosis of PD and its ability to distinguish PD from essential tremor (ET in an Iranian population. Materials and Methods: TCS of substantia nigra (SN was performed on 50 PD, 48 ET, and 50 healthy controls by two blinded investigators. Results: Bilateral SN margin over 0.20 cm 2 was found in 39 (90% and 7 (15% in PD and ET patients, respectively. Furthermore, 4 (8% of healthy control displayed this particular echo feature as well (false positives. SN hyperechogenicity ≥0.20 cm 2 was considered as a cut-off point to detected PD. Accordingly, TCS proved 90% (95% confidence interval [CI]: 77.85-97.35 sensitive and 92% ( 95% CI: 80.75-97.73 specific for the detection of PD by visualizing the SN. Conclusion: SN hyperechogenicity ≥20 cm 2 is a specific feature of PD. Since, the symptoms of PD and ET might be overlapping; this method seems to be reliable to confirm PD diagnosis in doubtful clinical cases. Further studies in years to come are warranted to shed light on standardized data for Iranian to enhance the validity of TCS.

  19. Subthalamic and Cortical Local Field Potentials Associated with Pilocarpine-Induced Oral Tremor in the Rat.

    Science.gov (United States)

    Long, Lauren L; Podurgiel, Samantha J; Haque, Aileen F; Errante, Emily L; Chrobak, James J; Salamone, John D

    2016-01-01

    Tremulous jaw movements (TJMs) are rapid vertical deflections of the lower jaw that resemble chewing but are not directed at any particular stimulus. In rodents, TJMs are induced by neurochemical conditions that parallel those seen in human Parkinsonism, including neurotoxic or pharmacological depletion of striatal dopamine (DA), DA antagonism, and cholinomimetic administration. Moreover, TJMs in rodents can be attenuated by antiparkinsonian agents, including levodopa (L-DOPA), DA agonists, muscarinic antagonists, and adenosine A2A antagonists. In human Parkinsonian patients, exaggerated physiological synchrony is seen in the beta frequency band in various parts of the cortical/basal ganglia/thalamic circuitry, and activity in the tremor frequency range (3-7 Hz) also has been recorded. The present studies were undertaken to determine if tremor-related local field potential (LFP) activity could be recorded from motor cortex (M1) or subthalamic nucleus (STN) during the TJMs induced by the muscarinic agonist pilocarpine, which is a well-known tremorogenic agent. Pilocarpine induced a robust TJM response that was marked by rhythmic electromyographic (EMG) activity in the temporalis muscle. Compared to periods with no tremor activity, TJM epochs were characterized by increased LFP activity in the tremor frequency range in both neocortex and STN. Tremor activity was not associated with increased synchrony in the beta frequency band. These studies identified tremor-related LFP activity in parts of the cortical/basal ganglia circuitry that are involved in the pathophysiology of Parkinsonism. This research may ultimately lead to identification of the oscillatory neural mechanisms involved in the generation of tremulous activity, and promote development of novel treatments for tremor disorders.

  20. Differential analysis of muscle fatigue induced elbow and wrist tremor in controlled laparoscopic manoeuvring.

    Science.gov (United States)

    Chandra, Sourav; Hayashibe, Mitsuhiro; Thondiyath, Asokan; Ramalingam, Manickam

    2017-09-01

    Fatigue induced hand tremor (FIT) is a primary limiting concern for the prolonged surgical intervention in minimally invasive surgery (MIS) and robot-assisted-minimally invasive surgery (RAMIS). A thorough analysis is necessary to understand the FIT characteristics in laparoscopic tool movement. The primary aim of this study is to perform a differential analysis of the elbow and wrist tremor due to muscle fatigue in laparoscopic manoeuvring. We have introduced a joint angle based tremor analysis method, which enables us to perform a differential study of FIT characteristics at the individual joint. Experimental data was acquired from a group of subjects during static and dynamic laparoscopic movement in an imitative RAMIS master manipulation scenario. A repetitive task was performed with a total span of 1 h for observing the effect of muscle fatigue. Along with the joint angle variation, surface electromyography (sEMG) signal was also studied in the analysis. The wrist tremor is more predominant than tremor generated at the elbow, especially in highly fatigued condition. The high-frequency tremor (>4 Hz) is contributed by the wrist joint. Moreover, the variation of the wrist and elbow tremor ratio was found to be dependent upon the experience of the surgeons. In this work, we have investigated the attribution of elbow and wrist joints in FIT during laparoscopic tool manipulation. The outcomes may be useful for the design of robot-assisted surgical manipulator, and can be used for quality assessment of surgical training as well. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Semiautomated tremor detection using a combined cross-correlation and neural network approach

    Science.gov (United States)

    Horstmann, Tobias; Harrington, Rebecca M.; Cochran, Elizabeth S.

    2013-01-01

    Despite observations of tectonic tremor in many locations around the globe, the emergent phase arrivals, low‒amplitude waveforms, and variable event durations make automatic detection a nontrivial task. In this study, we employ a new method to identify tremor in large data sets using a semiautomated technique. The method first reduces the data volume with an envelope cross‒correlation technique, followed by a Self‒Organizing Map (SOM) algorithm to identify and classify event types. The method detects tremor in an automated fashion after calibrating for a specific data set, hence we refer to it as being “semiautomated”. We apply the semiautomated detection algorithm to a newly acquired data set of waveforms from a temporary deployment of 13 seismometers near Cholame, California, from May 2010 to July 2011. We manually identify tremor events in a 3 week long test data set and compare to the SOM output and find a detection accuracy of 79.5%. Detection accuracy improves with increasing signal‒to‒noise ratios and number of available stations. We find detection completeness of 96% for tremor events with signal‒to‒noise ratios above 3 and optimal results when data from at least 10 stations are available. We compare the SOM algorithm to the envelope correlation method of Wech and Creager and find the SOM performs significantly better, at least for the data set examined here. Using the SOM algorithm, we detect 2606 tremor events with a cumulative signal duration of nearly 55 h during the 13 month deployment. Overall, the SOM algorithm is shown to be a flexible new method that utilizes characteristics of the waveforms to identify tremor from noise or other seismic signals.

  2. Comparative study of tectonic tremor locations: Characterization of slow earthquakes in Guerrero, Mexico

    Science.gov (United States)

    Maury, J.; Ide, S.; Cruz-Atienza, V. M.; Kostoglodov, V.; González-Molina, G.; Pérez-Campos, X.

    2016-07-01

    Deep tectonic tremor in Guerrero, Mexico, has been observed using dense temporal seismic networks (i.e., the Meso-American Subduction Experiment and Guerrero Gap Experiment (G-GAP) arrays) during two different time periods. We apply a set of seismic waveform analysis methods to these data sets to constrain the locations of tremors and determine the associated moment tensors. First we detect and locate the tremors. Next, very low frequency (VLF) signals are identified by stacking waveform data during tremor bursts, and their moment tensors are determined. Finally, to better investigate the link between tremors and VLF earthquakes, we detect VLF events using a matched filtering algorithm to search continuous seismic records. None of the 11 VLF events detected by this method occurred in the absence of tremor bursts suggesting they are indeed part of the same phenomena. Unlike previous investigations, our results for the G-GAP period reveal that downdip tremor activity (i.e., in the so-called "sweet spot") is segmented into two patches separated by 40 km in the along-trench direction, indicating possible variations in the geometry of the plate interface and/or slab effective pressure. Moment tensors of VLF signals are consistent with shear slip on the near-horizontal plate interface, but source depths are about 5 km deeper than the established plate interface. The slip directions of the VLF events are slightly ( 10°) counterclockwise of the plate convergence direction, indicating that strain energy promoting left-lateral strike-slip motion may accumulate in the continental crust during the interseismic period.

  3. Migrating tremors illuminate complex deformation beneath the seismogenic San Andreas fault

    Science.gov (United States)

    Shelly, D.R.

    2010-01-01

    The San Andreas fault is one of the most extensively studied faults in the world, yet its physical character and deformation mode beneath the relatively shallow earthquake-generating portion remain largely unconstrained. Tectonic non-volcanic tremor, a recently discovered seismic signal probably generated by shear slip on the deep extension of some major faults, can provide new insight into the deep fate of such faults, including that of the San Andreas fault near Parkfield, California. Here I examine continuous seismic data from mid-2001 to 2008, identifying tremor and decomposing the signal into different families of activity based on the shape and timing of the waveforms at multiple stations. This approach allows differentiation between activities from nearby patches of the deep fault and begins to unveil rich and complex patterns of tremor occurrence. I find that tremor exhibits nearly continuous migration, with the most extensive episodes propagating more than 20 kilometres along fault strike at rates of 15-80 kilometres per hour. This suggests that the San Andreas fault remains a localized through-going structure, at least to the base of the crust, in this area. Tremor rates and recurrence behaviour changed markedly in the wake of the 2004 magnitude-6.0 Parkfield earthquake, but these changes were far from uniform within the tremor zone, probably reflecting heterogeneous fault properties and static and dynamic stresses decaying away from the rupture. The systematic recurrence of tremor demonstrated here suggests the potential to monitor detailed time-varying deformation on this portion of the deep San Andreas fault, deformation which unsteadily loads the shallower zone that last ruptured in the 1857 magnitude-7.9 Fort Tejon earthquake. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  4. Movement-related dynamics of cortical oscillations in Parkinson's disease and essential tremor.

    Science.gov (United States)

    Kondylis, Efstathios D; Randazzo, Michael J; Alhourani, Ahmad; Lipski, Witold J; Wozny, Thomas A; Pandya, Yash; Ghuman, Avniel S; Turner, Robert S; Crammond, Donald J; Richardson, R M

    2016-08-01

    Recent electrocorticography data have demonstrated excessive coupling of beta-phase to gamma-amplitude in primary motor cortex and that deep brain stimulation facilitates motor improvement by decreasing baseline phase-amplitude coupling. However, both the dynamic modulation of phase-amplitude coupling during movement and the general cortical neurophysiology of other movement disorders, such as essential tremor, are relatively unexplored. To clarify the relationship of these interactions in cortical oscillatory activity to movement and disease state, we recorded local field potentials from hand sensorimotor cortex using subdural electrocorticography during a visually cued, incentivized handgrip task in subjects with Parkinson's disease (n = 11), with essential tremor (n = 9) and without a movement disorder (n = 6). We demonstrate that abnormal coupling of the phase of low frequency oscillations to the amplitude of gamma oscillations is not specific to Parkinson's disease, but also occurs in essential tremor, most prominently for the coupling of alpha to gamma oscillations. Movement kinematics were not significantly different between these groups, allowing us to show for the first time that robust alpha and beta desynchronization is a shared feature of sensorimotor cortical activity in Parkinson's disease and essential tremor, with the greatest high-beta desynchronization occurring in Parkinson's disease and the greatest alpha desynchronization occurring in essential tremor. We also show that the spatial extent of cortical phase-amplitude decoupling during movement is much greater in subjects with Parkinson's disease and essential tremor than in subjects without a movement disorder. These findings suggest that subjects with Parkinson's disease and essential tremor can produce movements that are kinematically similar to those of subjects without a movement disorder by reducing excess sensorimotor cortical phase-amplitude coupling that is characteristic of these

  5. Differences in brain activation between tremor- and nontremor-dominant Parkinson disease.

    Science.gov (United States)

    Prodoehl, Janey; Planetta, Peggy J; Kurani, Ajay S; Comella, Cynthia L; Corcos, Daniel M; Vaillancourt, David E

    2013-01-01

    OBJECTIVE To compare differences in functional brain activity between tremor- and nontremor-dominant subtypes of Parkinson disease (PD) using functional magnetic resonance imaging. DESIGN In our study, patients with tremor-dominant PD and those with nontremor-dominant PD performed a grip task, and the results obtained were compared using voxelwise analysis. Areas of the brain that were significantly different were then examined using a region-of-interest analysis to compare these patients with healthy controls. Voxel-based morphometry was used to determine macroscopic differences in gray and white matter volume between patient groups. SETTING University-affiliated research institution. PARTICIPANTS A total of 20 drug-naive patients with PD (10 with tremor-dominant PD and 10 with nontremor-dominant PD) and a total of 20 healthy controls. MAIN OUTCOME MEASURES Blood oxygenation level-dependent activation and percent signal change. RESULTS Robust findings across both voxelwise and region-of-interest analyses showed that, compared with patients with tremor-dominant PD, patients with nontremor-dominant PD had reduced activation in the ipsilateral dorsolateral prefrontal cortex, the globus pallidus interna, and the globus pallidus externa. Region-of-interest analyses confirmed that patients with nontremor-dominant PD had reduced activity in the ipsilateral dorsolateral prefrontal cortex, the globus pallidus interna, and the globus pallidus externa compared with patients with tremor-dominant PD and healthy controls. Patients with tremor-dominant PD had increased activity in the contralateral dorsolateral prefrontal cortex compared with patients with nontremor-dominant PD and healthy controls. These results could not be explained by differences in gray or white matter volume. CONCLUSIONS Reduced brain activity occurs in the prefrontal cortex and globus pallidus of patients with nontremor-dominant PD compared with both patients with tremor-dominant PD and healthy controls

  6. Non-Volcanic Tremors beneath the Southern Central Range in Taiwan

    Science.gov (United States)

    Sun, W.; Lin, C.; Peng, Z.; Chao, K.

    2011-12-01

    Deep non-volcanic tremors (NVT) triggered by teleseismic surface waves have been systematically observed in the Central Range in Taiwan recently. The discovery of NVT in Taiwan, as an arc-continental type collision environment, would provide us better understanding of critical conditions related to tremor occurrence and of the fault mechanics at the bottom of the seismogenic layer. Aiming to capture more NVT events, we have further installed two dense 36-element, small-aperture seismic arrays in the Liouguei and Lidao areas. Two arrays are respectively located about 20 km in southwest and northeast to the tremor sources reported at the southern Central Range of Taiwan. In each array, the short-period, vertical-channel GS-11D sensors with 4.5Hz natural frequency were laid out on the relatively flat parts of the mountain areas in a grid of approximately 100 by 80 meters. We had successfully recorded nine sets of continuous seismic data for totally 4034 hours among the first half year of 2011. Among those data, as we expected, the two arrays recorded clear tremors triggered by the great Tohoku earthquake (Mw=8.9) on 2011/03/11. Based on the beamforming results of the western and eastern arrays, the possible tremor sources come from N60E and just beneath it, respectively. Therefore, we believe the possible source of triggered tremors were nearby the Lidao area. Since the array analysis is able to significantly increase the level of tremor detection, we are examining other possible NVT events during the deployed period and the possible conditions related to NVT events, such as the passing seismic waves from other large regional earthquakes.

  7. [Missense mutation R1345Q in CACNA1A gene causes a new type of ataxia with episodic tremor: clinical features, genetic analysis and treatment in a familial case].

    Science.gov (United States)

    Jiang, Hai-Shan; Wang, Dong-Mei; Wang, Qun; Yang, Man; Wang, Wei; Pan, Su-Yue; Hu, Ya-Fang

    2016-06-20

    Mutations in CACNA1A, which encodes the P/Q-type calcium channel subunit, are responsible for at least 3 allelic diseases, namely type 2 episodic ataxia (EA-2), familial hemiplegic migraine?type-1 (FHM1), and spinocerebellar ataxia type-6?(SCA 6). Herein we present a case of ataxia with episodic tremors in a 19-year-old man with a missense mutation of CACNA1A gene and summarize the clinical features, genetic analysis and treatment in this case and in his affected family members. Physical examinations were conducted for the patient and his affected family members. DNA sample from the proband was analyzed with next-generation sequencing technology to identify the causative mutation. Sanger sequencing was used to confirm the gene mutation in the family members. Physical examinations of the patient revealed signs of ataxia, drunken gait, and tremor of his head and body. Four other members in his family had similar but much milder symptoms. A heterozygous missense mutation in CACNA1A (NM_001127221.1 c.4034G->A, p.R1345Q, exon 25) was identified in the proband, which was confirmed in the affected family members. The proband did not respond to methazolamide treatment, but his tremor symptom was well controlled with flunarizine, a calcium channel blocker. Based on the clinical features, mutation analysis and treatment response, we suggest that this patient with a missense CACNA1A mutation, R1345Q, has a new type of ataxia with episodic tremor other than any of EA2, FHM1, or SCA 6.

  8. A family of repeating low-frequency earthquakes at the downdip edge of tremor and slip

    Science.gov (United States)

    Sweet, Justin R.; Creager, Kenneth C.; Houston, Heidi

    2014-09-01

    analyze an isolated low-frequency earthquake (LFE) family located at the downdip edge of the main episodic tremor and slip (ETS) zone beneath western Washington State. The 9000 individual LFEs from this repeating family cluster into 198 swarms that recur roughly every week. Cumulative LFE seismic moment for each swarm correlates strongly with the time until the next swarm, suggesting that these LFE swarms are time predictable. Precise double-difference relative locations for 700 individual LFEs within this family show a distribution that is approximately 2 km long and 500 m wide, elongated parallel to the relative plate convergence direction. The distribution of locations (<300 m vertical spread) lies within a few hundred meters of two different plate interface models and has a similar dip. Peak-to-peak LFE S wave amplitudes range from 0.2 to 18 nm. Individual LFEs exhibit a trend of increasing magnitude during swarms, with smaller events at the beginning and the largest events toward the end. The largest LFEs cluster in a small area (300 m radius) coincident with maximum LFE density. We propose that the less-concentrated smaller LFEs act to unlock this patch core, allowing it to fully rupture in the largest LFEs, usually toward the end of a swarm. We interpret the patch responsible for producing these LFEs as a subducted seamount on the downgoing Juan de Fuca (JdF) plate. LFE locking efficiency (slip estimated during 5 years from summing LFE seismic moment divided by plate-rate-determined slip) is at most 20% and is highly concentrated in two ˜50 m radius locations in the larger patch core. Estimated individual LFE stress drops range from 1 to 20 kPa, but could also be significantly larger.

  9. Mirtazapine in essential tremor: a double-blind, placebo-controlled pilot study.

    Science.gov (United States)

    Pahwa, Rajesh; Lyons, Kelly E

    2003-05-01

    We sought to determine whether mirtazapine is safe and well-tolerated as a treatment for essential tremor (ET). We studied mirtazapine in a randomized, double-blind, placebo-controlled, crossover study of 17 ET patients. Patients were started with 15 mg per day of either mirtazapine or placebo for 1 week and the dose was escalated weekly until the targeted dose of 45 mg per day was achieved. This dose was maintained for 2 weeks. Tremor was assessed at baseline and after 14 days of 45 mg of mirtazapine or placebo. There was a minimum washout period of 14 days between the two arms of the study. Tremor assessments included global improvement, Fahn Tolosa Marin Tremor Rating Scale, Beck Depression Inventory and the Parkinson's Disease Questionnaire-39. Patient global improvement ratings indicated that in the placebo condition 12 patients were unchanged and 1 patient was mildly improved. In the mirtazapine condition, 10 patients were unchanged, 2 were moderately improved and 1 was markedly improved. There was no significant improvement with mirtazapine or placebo compared to baseline as measured by the Tremor Rating Scale. Adverse effects were more common in the mirtazapine group and included drowsiness, confusion, dry mouth, weight gain, polyuria, itching, nausea, gait and balance problems, blurred vision, and bad taste. We conclude that the majority of the ET patients do not benefit from mirtazapine. Mirtazapine has significant adverse effects and should be used cautiously in ET patients.

  10. Dystonia and tremor following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Klawans, H.L.

    1987-01-01

    Forty-seven railroad workers who were exposed to polychlorinated phenols, including dioxin (TCDD), during 1979 while cleaning up the chemical spillage following damage to a tank car filled with these chemicals were followed medically for the subsequent 6 years. Two committed suicide. The initial neurological complaints included a sense of fatigue and muscle aching, both of which have been reported in other individuals following dioxin exposure. On detailed neurological examination in December, 1985, 24 of 45 had dystonic writer's cramp and/or other action dystonias of the hands. None of the involved individuals had a family history of dystonia, and all 24 dated the onset of the dystonia to the first 2 to 3 years subsequent to their toxic exposure. The dystonias varied in severity but were usually mild. No other types of dystonic involvement were recognized. Thirty-five of the 45 individuals also manifested postural and terminal intention tremor which resembled benign essential tremor. None of the involved individuals had a family history of tremor, and all 35 of those affected dated the onset of the tremor to some time subsequent to their toxic exposure. Forty-three of 45 patients had histories and findings suggestive of peripheral neuropathy. This is the first report relating any type of dystonia to prior dioxin exposure and the first report relating action dystonia, such as dystonic writer's cramp, and postural/terminal intention tremor, to toxic exposure of any type.

  11. Pramipexole, a nonergot dopamine agonist, is effective against rest tremor in intermediate to advanced Parkinson's disease.

    Science.gov (United States)

    Künig, G; Pogarell, O; Möller, J C; Delf, M; Oertel, W H

    1999-01-01

    We evaluated the efficacy of the nonergot dopamine receptor agonist pramipexole in 16 patients with advanced Parkinson's disease and marked rest tremor during an "on" period. The patients were drawn from a larger placebo-controlled, double-blind, randomized trial, which was not originally designed to investigate the effect of pramipexole on tremor. Eleven patients received pramipexole. The first effects were seen with a pramipexole dose of 0.75 mg/d with a reduction of the tremor item A of Unified Parkinson's Disease Rating Scale (UPDRS III, "on" state) by 25% and of rigidity and akinesia by 22%. Under the highest dose, 4.5 mg/d, the tremor score was improved by 61% over baseline (p < 0.0056, Wilcoxon signed rank) and the sum of rigidity and akinesia items by 66% (p < 0.0038, Wilcoxon signed rank). Five patients received placebo and did not improve. Based on this sample of patients, the nonergot dopamine receptor agonist pramipexole appears to have a potent anti-rest tremor action while being effective against akinesia and rigidity.

  12. Frequency and Factors of Tremor, Palpitation, and Cramp in Patients with COPD and Asthma

    Directory of Open Access Journals (Sweden)

    Sema Demir

    2015-04-01

    Full Text Available Objective: To evaluate the frequency and predictability of side effects, including tremor, cramp, and palpitation, due to treatment in patients with chronic obstructive pulmonary disease and asthma. Methods: We prepared a standard questionnaire for 299 patients concerning their diagnosis, treatment, and side effects of the treatment in February 2007 at Hacettepe University, Faculty of Medicine, Department of Pulmonary Diseases. We prospectively examined the clinical status of the patients and side effects of the treatment at the 15th, 30th, and 180th days of the treatment. Results: In our study, there were 38 (12.7% patients with drug-induced tremor. Of these, 27 (71.1% had asthma (p=0.004 and 18 (47.4% had anamnestic palpitation. Drug-induced tremor risk was 15.3 times higher in patients who used a beta-mimetic compared with those who used any drugs. Cramp risk increased with beta-mimetic use only. In our study, drug-induced tremor was still present at the 180th day of examination in 32 (84.2% patients. Conclusion: This study demonstrated that side effects, including tremor, palpitation, and cramp, were more common in our patients compared with those in other studies. These side effects were directly related to the primary disease and the use of beta-2-agonists. Another finding of our study is that tolerance did not develop as much as that reported in literature.

  13. A Pilot Study of Botulinum Toxin for Jerky, Position-Specific, Upper Limb Action Tremor

    Science.gov (United States)

    Saifee, Tabish A.; Teodoro, Tiago; Erro, Roberto; Edwards, Mark J.; Cordivari, Carla

    2016-01-01

    Background We aimed to investigate the efficacy and safety of botulinum toxin (BT) injections for jerky action tremor of the upper limb. Methods We performed an uncontrolled, prospective study of electromyography (EMG)-guided BT injections for jerky, position-specific, upper limb action tremor. The primary outcome was clinical global impression at 3–6 weeks after baseline. Results Eight patients with jerky, position-specific action tremor involving the upper limb were consecutively recruited. After a median follow-up of 4.4 weeks (interquartile range [IQR] 3.6–6 weeks), four of them rated themselves as “improved” and two as “much improved.” Five of these six subjects reported improvements in specific activities of daily living (bringing liquids to mouth, feeding, shaving, and dressing). Upper limb subscore of the Fahn–Tolosa–Marin Tremor Rating Scale (FTM) significantly decreased from 4.5 (4–6) to 3 (2–5) (p = 0.01). Discussion This pilot, prospective cohort study suggests that EMG-guided BT injections may improve jerky, position-specific, upper limb action tremor. Placebo-controlled studies evaluating larger samples of patients are warranted to confirm these findings. PMID:27818844

  14. Continuous theta-burst stimulation of the primary motor cortex in essential tremor.

    Science.gov (United States)

    Hellriegel, Helge; Schulz, Eva M; Siebner, Hartwig R; Deuschl, Günther; Raethjen, Jan H

    2012-05-01

    We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation. 10 Patients with ET and 10 healthy controls underwent transcranial continuous theta-burst stimulation (cTBS) of the left primary motor hand area at 80% (real cTBS) and 30% (control cTBS) of active motor threshold in two separate sessions at least one week apart. Postural tremor was rated clinically and measured accelerometrically before and after cTBS. Corticospinal excitability was assessed by recording the motor evoked potentials (MEP) from the first dorsal interosseous muscle. Real cTBS but not control cTBS reduced the tremor total power assessed with accelerometry. This beneficial effect was subclinical as there were no significant changes in clinical tremor rating after real cTBS. Relative to control cTBS, real cTBS reduced corticospinal excitability in the stimulated primary motor cortex only in healthy controls but not in ET patients. Real cTBS has a beneficial effect on ET. Since cTBS did not induce a parallel reduction in corticospinal excitability, this effect was not mediated by a suppression of the corticospinal motor output. "Inhibitory" cTBS of M1 leads to a consistent but subclinical reduction in tremor amplitude. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  15. Tectonic tremor and microseismicity associated with shallow slow slip along the northern Hikurangi Margin, New Zealand

    Science.gov (United States)

    Todd, E. K.; Schwartz, S. Y.

    2015-12-01

    The detection of circum-Pacific slow slip events (SSEs) along with associated tectonic tremor and microseismicity has led to numerous investigations into the modes and timescales of deformation in subduction zone boundaries. This discovery has shed light on a broader range of strain release processes that range from aseismic creep at plate convergence rates (cm/yr) to traditional earthquake slip rates (m/s). The largest SSEs along the northern Hikurangi subduction margin occur offshore Gisborne, New Zealand every 18-24 months at depths less than 15 km. We present a systematic investigation of tremor and microseismicity associated with these shallow SSEs from 2010 to the present using land data from the New Zealand National Seismograph Network operated by GeoNet (http://geonet.org.nz) and ocean-bottom data from the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip (HOBITSS) project. The HOBITSS project deployed an array of ocean-bottom seismometers and absolute pressure gauges between May 2014 and June 2015 above the Gisborne SSE patch. These instruments were in place during a large SSE in September/October 2014. Tremor and seismicity associated with Gisborne SSEs primarily occur along the downdip edge of the slip patch, but the addition of data from ocean-bottom stations located directly above the slip patch will reveal the updip extent of tremor and microseismicity related to these SSEs.

  16. The 2011 unrest at Katla volcano: characterization and interpretation of the tremor sources

    CERN Document Server

    Sgattoni, Giulia; Einarsson, Páll; Lucchi, Federico; Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Tryggvason, Ari

    2016-01-01

    A 23 hour tremor burst was recorded on July 8-9th 2011 at the Katla subglacial volcano, one of the most active and hazardous volcanoes in Iceland. This was associated with deepening of cauldrons on the ice cap and a glacial flood that caused damage to infrastructure. Increased earthquake activity within the caldera started a few days before and lasted for months afterwards and new seismic activity started on the south flank. No visible eruption broke the ice and the question arose as to whether this episode relates to a minor subglacial eruption with the tremor being generated by volcanic processes, or by the flood. The tremor signal consisted of bursts with varying amplitude and duration. We have identified and described three different tremor phases, based on amplitude and frequency features. A tremor phase associated with the flood was recorded only at stations closest to the river that flooded, correlating in time with rising water level observed at gauging stations. Using back-projection of double cross-...

  17. O terramoto de Lisboa de 1755: tremores e temores

    Directory of Open Access Journals (Sweden)

    María José Ferro TAVARES

    2009-11-01

    Full Text Available RESUMEN: Con anterioridad al gran terremoto de 1755 ya se habían registrado en Portugal temblores de tierra de intensidad bastante significativa. En la actualidad, las cartas sismotectónicas enseñan que tanto la región de la Gran Lisboa, como la costa sur atlántica y costa algarvia son las que presentan mayor peligrosidad sísmica. Los temblores de tierra fueron desde siempre un asunto de preocupación para la población portuguesa que habitaba estas regiones, provocando temores y fobias que fueron transmitidos de generación en generación. En el presente trabajo se procura identificar las señales de cambios o de continuidad en la población portuguesa y las reacciones ante los efectos de los terremotos que desde tiempos remotos afectaran al país. Particular atención es atribuida a las interpretaciones de raíz escatológica, las primeras que surgieron y que gradualmente fueran sustituidas en el siglo XVII por explicaciones que invocaban la existencia de causas primeras (divinas y causas segundas (naturales en la discusión de este tipo de fenómenos. Va a ser con el terremoto de Lisboa, en 1755, cuando la experimentación surge como medio de explicación, inicialmente apenas en términos retóricos, para después, a partir del siglo XIX, en términos científicos, sustentar la aparición y desarrollo de la propia sismología. En Portugal, mientras exista un copioso acervo bibliográfico en lo que concierne a las referidas explicaciones, una actitud pragmática ante los terremotos ha prevalecido siempre, en el sentido de que es siempre más importante mitigar sus efectos, particularmente los efectos en la salud pública en lo que se refiere al terremoto de Lisboa, que determinar sus causas exactas.ABSTRACT: Before the great Lisbon earthquake of 1755 the continental part of Portugal had already experienced strong, catastrophic tremors; present day seismotectonic maps show that indeed the metropolitan area of the capital city, as well as

  18. O terramoto de Lisboa de 1755: tremores e temores

    Directory of Open Access Journals (Sweden)

    María José Ferro TAVARES

    2009-11-01

    Full Text Available RESUMEN: Con anterioridad al gran terremoto de 1755 ya se habían registrado en Portugal temblores de tierra de intensidad bastante significativa. En la actualidad, las cartas sismotectónicas enseñan que tanto la región de la Gran Lisboa, como la costa sur atlántica y costa algarvia son las que presentan mayor peligrosidad sísmica. Los temblores de tierra fueron desde siempre un asunto de preocupación para la población portuguesa que habitaba estas regiones, provocando temores y fobias que fueron transmitidos de generación en generación. En el presente trabajo se procura identificar las señales de cambios o de continuidad en la población portuguesa y las reacciones ante los efectos de los terremotos que desde tiempos remotos afectaran al país. Particular atención es atribuida a las interpretaciones de raíz escatológica, las primeras que surgieron y que gradualmente fueran sustituidas en el siglo XVII por explicaciones que invocaban la existencia de causas primeras (divinas y causas segundas (naturales en la discusión de este tipo de fenómenos. Va a ser con el terremoto de Lisboa, en 1755, cuando la experimentación surge como medio de explicación, inicialmente apenas en términos retóricos, para después, a partir del siglo XIX, en términos científicos, sustentar la aparición y desarrollo de la propia sismología. En Portugal, mientras exista un copioso acervo bibliográfico en lo que concierne a las referidas explicaciones, una actitud pragmática ante los terremotos ha prevalecido siempre, en el sentido de que es siempre más importante mitigar sus efectos, particularmente los efectos en la salud pública en lo que se refiere al terremoto de Lisboa, que determinar sus causas exactas.ABSTRACT: Before the great Lisbon earthquake of 1755 the continental part of Portugal had already experienced strong, catastrophic tremors; present day seismotectonic maps show that indeed the metropolitan area of the capital city, as well as

  19. Is HEADS in our heads?

    DEFF Research Database (Denmark)

    Boisen, Kirsten A; Hertz, Pernille Grarup; Blix, Charlotte

    2016-01-01

    BACKGROUND: Outpatient clinic visits are a window of opportunity to address health risk behaviors and promote a healthier lifestyle among young people. The HEADS (Home, Education, Eating, Activities, Drugs [i.e. substance use including tobacco, alcohol, and illegal drugs], Sexuality [including...... care professionals participated. We found only small reported differences between staff and young patients regarding whether home, education, and activity were addressed. However, staff reported twice the rate of addressing smoking, alcohol, illegal drugs, sexuality, and contraception compared to young...... patients. Young patients reported that smoking, alcohol, illegal drugs, sexuality, and contraception were addressed significantly more at adult clinics in comparison to pediatric clinics. After controlling for age, gender and duration of illness, according to young patients, adjusted odds ratios...

  20. Increased LINGO1 in the cerebellum of essential tremor patients.

    Science.gov (United States)

    Delay, Charlotte; Tremblay, Cyntia; Brochu, Elodie; Paris-Robidas, Sarah; Emond, Vincent; Rajput, Ali H; Rajput, Alex; Calon, Frédéric

    2014-11-01

    Essential tremor (ET) is the most prevalent adult-onset movement disorder. Despite its health burden, no clear pathognomonic sign has been identified to date because of the rarity of clinicopathological studies. Moreover, treatment options are still scarce and have not significantly changed in the last 30 years, underscoring the urgent need to develop new treatment avenues. In the recent years, leucine-rich repeat (LRR) and immunoglobulin (Ig) domain-containing Nogo receptor-interacting proteins 1 and 2 (LINGO1 and LINGO2, respectively) have been increasingly regarded as possible ET modulators due to emerging genetic association studies linking LINGO with ET. We have investigated LINGO protein and messenger RNA (mRNA) expression in the cerebellum of patients with ET, patients with Parkinson's disease (PD), and a control group using Western immunoblotting and in situ hybridization. Protein levels of LINGO1, but not LINGO2, were significantly increased in the cerebellar cortex of ET patients compared with controls, particularly in individuals with longer disease duration. Compared with controls, LINGO1 protein levels were increased in the cerebellar white matter of PD and ET patients but, for the latter, only when disease duration exceeded 20 years. However, no alteration in LINGO1 mRNA was observed between groups in either the cerebellar cortex or the white matter. We observed alterations in LINGO expression in diseased brain that seemed to progress along with the disease, being initiated in the cerebellar cortex before reaching the white matter. Because LINGO up-regulation has been identified as a potential pathological response to ongoing neurodegenerative processes, the present data suggest that LINGO1 is a potential drug target for ET.

  1. Visual function alterations in essential tremor: A case report

    Directory of Open Access Journals (Sweden)

    David P. Piñero

    2015-09-01

    Full Text Available Our purpose is to report alterations in contrast sensitivity function (CSF and in the magno, parvo and koniocellular visual pathways by means of a multichannel perimeter in case of an essential tremor (ET. A complete evaluation of the visual function was performed in a 69-year old patient, including the analysis of the chromatic discrimination by the Fansworth–Munsell 100 hue test, the measurement of the CSF by the CSV-1000E test, and the detection of potential alteration patterns in the magno, parvo and koniocellular visual pathways by means of a multichannel perimeter. Visual acuity and intraocular pressure (IOP were within the ranges of normality in both eyes. No abnormalities were detected in the fundoscopic examination and in the optical coherence tomography (OCT exam. The results of the color vision examination were also within the ranges of normality. A significant decrease in the achromatic CSFs for right eye (RE and left eye (LE was detected for all spatial frequencies. The statistical global values provided by the multichannel perimeter confirms that there were significant absolute sensitivity losses compared to the normal pattern in RE. In the LE, only a statistically significant decrease in sensitivity was detected for the blue-yellow (BY channel. The pattern standard deviation (PSD values obtained in our patient indicated that there were significant localized losses compared to the normality pattern in the achromatic channel of the RE and in the red-green (RG channel of the LE. Some color vision alterations may be present in ET that cannot be detected with conventional color vision tests, such as the FM 100 Hue.

  2. Fusarium head blight of winter rye (Secale cereale L.

    Directory of Open Access Journals (Sweden)

    Irena Kiecana

    2012-12-01

    Full Text Available Investigations on Fusarium head blight of rye were carried out in the years 2005-2007 on 10 production fields in the Lublin region. The percentage of heads showing the fusariosis symptoms in the years 2005-2007 ranged from 0 to 7%. Mycological analysis of kernels and chaff obtained from heads with Fusarium blight (scab symptoms showed that Fusarium avenaceum, Fusarium culmorum and Fusarium sporotrichioides were the largest threat to heads of this cereal. The species of Fusarium poae and Fusarium crookwellense were also isolated from infected rye heads. The dominance of particular species in infecting rye heads was determined by weather conditions.

  3. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  4. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  5. Locating non-volcanic tremor along the San Andreas Fault using a multiple array source imaging technique

    Science.gov (United States)

    Ryberg, T.; Haberland, C.H.; Fuis, G.S.; Ellsworth, W.L.; Shelly, D.R.

    2010-01-01

    Non-volcanic tremor (NVT) has been observed at several subduction zones and at the San Andreas Fault (SAF). Tremor locations are commonly derived by cross-correlating envelope-transformed seismic traces in combination with source-scanning techniques. Recently, they have also been located by using relative relocations with master events, that is low-frequency earthquakes that are part of the tremor; locations are derived by conventional traveltime-based methods. Here we present a method to locate the sources of NVT using an imaging approach for multiple array data. The performance of the method is checked with synthetic tests and the relocation of earthquakes. We also applied the method to tremor occurring near Cholame, California. A set of small-aperture arrays (i.e. an array consisting of arrays) installed around Cholame provided the data set for this study. We observed several tremor episodes and located tremor sources in the vicinity of SAF. During individual tremor episodes, we observed a systematic change of source location, indicating rapid migration of the tremor source along SAF. ?? 2010 The Authors Geophysical Journal International ?? 2010 RAS.

  6. Using fuzzy logic to mitigate the effect of multiple-sclerosis tremors on a wheelchair joystick controller

    NARCIS (Netherlands)

    Corbett, Dan; Zwaag, van der Berend Jan; Antoniou, Grigoris; Slaney, John

    1998-01-01

    We have designed a fuzzy logic wheelchair controller to minimise the effect of Multiple Sclerosis hand tremors on a wheelchair joystick controller. The aim is to give people with Multiple Sclerosis better control of an electric wheelchair by removing tremors from the joystick signal. This has been a

  7. Familial cortical myoclonic tremor with epilepsy : A single syndromic classification for a group of pedigrees bearing common features

    NARCIS (Netherlands)

    van Rootselaar, AF; van Schaik, IN; van den Maagdenberg, AMJM; Koelman, JHTM; Callenbach, PMC; Tijssen, MAJ

    2005-01-01

    Fifty Japanese and European families with cortical myoclonic tremor and epilepsy have been reported under various names. Unfamiliarity with the syndrome often leads to an initial misdiagnosis of essential tremor or progressive myoclonus epilepsy. A detailed overview of the literature is lacking and

  8. Discrimination and characterization of Parkinsonian rest tremors by analyzing long-term correlations and multifractal signatures

    CERN Document Server

    Livi, Lorenzo

    2015-01-01

    In this paper, we analyze 48 signals of rest tremor velocity related to 12 distinct subjects affected by Parkinson's disease. The subjects belong to two different groups, formed by four and eight subjects with, respectively, high- and low-amplitude rest tremors. Each subject is tested in four settings, given by combining the use of deep brain stimulation and L-DOPA medication. We develop two main feature-based representations of such signals, which are obtained by considering (i) the long-term correlations and multifractal properties, and (ii) the power spectra. The feature-based representations are initially utilized for the purpose of characterizing the subjects under different settings. In agreement with previous studies, we show that deep brain stimulation does not significantly characterize neither of the two groups, regardless of the adopted representation. On the other hand, the medication effect yields statistically significant differences in both high- and low-amplitude tremor groups. We successively...

  9. Antagonism of quercetin against tremor induced by unilateral striatal lesion of 6-OHDA in rats.

    Science.gov (United States)

    Mu, Xin; Yuan, Xia; Du, Li-Da; He, Guo-Rong; Du, Guan-Hua

    2016-01-01

    Quercetin, a flavonoid present in many plants, is reported to be effective in models of neurodegenerative diseases. The aim of the present study was to evaluate the anti-tremor effects of quercetin in 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. In rats, quercetin had no effect on apomorphine-induced rotations, but it could significantly attenuate muscle tremor of 6-OHDA lesioned rats. Interestingly, quercetin could decrease the burst frequency in a dose- and time-dependent manner. These results suggest that quercetin may have a protective effect on models to mimic muscle tremors of Parkinson's disease. This effect of quercetin may be associated with serotonergic system, but further study is needed.

  10. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease.

    Science.gov (United States)

    Rose, Martin H; Løkkegaard, Annemette; Sonne-Holm, Stig; Jensen, Bente R

    2013-04-01

    We investigated lower-extremity isometric tremor Approximate Entropy (irregularity), torque steadiness and rate of force development (RFD) and their associations to muscle activation strategy during isometric knee extensions in patients with Parkinson's disease (PD). Thirteen male patients with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD and the patients had increased muscle coactivation. A markedly lower RFD was found in PD and the decreased RFD correlated with reduced agonist muscle activation. Furthermore, patient RFD correlated with the Movement-Disorder-Society-Unified-Parkinson's-Disease-Rating-Scale 3 (motor part) scores. We concluded that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation.

  11. Corticomuscular coherence in asymptomatic first-degree relatives of patients with essential tremor.

    Science.gov (United States)

    Raethjen, Jan; Muthuraman, Muthuraman; Kostka, Achim; Nahrwold, Martin; Hellriegel, Helge; Lorenz, Delia; Deuschl, Günther

    2013-05-01

    Essential tremor (ET) follows an autosomal dominant type of inheritance in the majority of patients, yet its genetic basis has not been identified. Its exact origin is still elusive, but coherence measurements between electromyography tremor bursts and electroencephalography unequivocally demonstrate a correlation. We tested these measurements in 37 healthy first-degree relatives (children) of patients with essential tremor (ET) and a group of 37 age-matched and sex-matched controls. Pooled coherence spectra of the maximally coherent electroencephalogram electrodes were computed for ET relatives and controls. The maximal coherence and its frequency were significantly higher in ET relatives than in controls during the pinch grip task and during slow hand movements. Electromyography amplitude (root-mean-square) was slightly but significantly greater in ET relatives, whereas 2-Hz to 40-Hz power and spectral peak frequency were not different. The presymptomatic alteration in corticomuscular interaction may reflect a role of genetic factors. Copyright © 2013 Movement Disorder Society.

  12. Joystick use for virtual power wheelchair driving in individuals with tremor: pilot study.

    Science.gov (United States)

    Dicianno, Brad E; Sibenaller, Sara; Kimmich, Claire; Cooper, Rory A; Pyo, Jay

    2009-01-01

    People with disabilities such as multiple sclerosis and Parkinson's disease have difficulty operating conventional movement-sensing joysticks (MSJs) because of varying levels of tremor. We developed an isometric joystick (IJ) that has performed as well as a conventional MSJ when used by persons with upper-limb impairments in real and virtual wheelchair driving tasks. The Weighted-Frequency Fourier Linear Combiner (WFLC) filter has been used to cancel tremor effectively in microsurgery. In this study, we compared an MSJ, IJ, and IJ with the WFLC filter in individuals performing a virtual driving task. Although the WFLC filter did not improve driving performance in this study, the IJ without a filter yielded better results than the conventional MSJ and thus may be a potential alternative to the MSJ in minimizing the effects of tremor.

  13. Six years of tectonic tremor observations prior to the Mw 7.4 March 20, 2012 Ometepec Earthquake

    Science.gov (United States)

    Sit, S. M.; Brudzinski, M. R.; Schlanser, K. M.; Cabral-Cano, E.; Arciniega-Ceballos, A.; DeMets, C.

    2012-12-01

    Observations of episodic tremor and slip (ETS) at several major tectonic boundaries have suggested a potential temporal relationship between the new seismic phenomena and megathrust earthquake events. The subduction zone in Oaxaca, Mexico provides an ideal locality to investigate this potential relationship, where we obtain a multi-year record of tectonic tremor detections and slow slip observations prior to the recent Mw 7.4 March 20, 2012 Ometepec earthquake. The preliminary epicenter, depth (20 km), and finite fault model all place the earthquake at the downdip edge of the band of background seismicity that is thought to outline the boundary between the seismogenic zone and transition zone of the plate interface. To detect tectonic tremor, we take advantage of its unique frequency content by scanning multiple frequency passbands where tremor (2-5 Hz), regional seismicity (10-15 Hz), and teleseismic surface waves (0.02-0.1 Hz) are present. We calculate a ratio of amplitudes favoring tremor behavior and downweighting activity from the other frequency passbands. Application of our technique allows us to quickly examine the prevalence of tremor beginning in mid-2006. Results from our frequency-based detection algorithm are in good agreement with previous tremor detections and locations in Oaxaca and additionally detects several previously unidentified low amplitude, short duration tremor episodes. Tremor occurs over a relatively short time period, 2-10 days, recurs as often as every 2-3 months, and does not regularly correlate with periods of large slow slip that tend to last several months and occur further updip. These observations are more consistent with those from Nankai than Cascadia. Preliminary analysis suggests that no obvious change in tremor prevalence occurred prior to the 2012 Ometepec earthquake; however, a variety of GPS inferred slow slip signals begin in the months leading up to the event. The puzzling relationship between tremor, slow slip, and

  14. Deep Tectonic Tremor in Haiti triggered by the 2010/02/27 Mw8.8 Maule, Chile earthquake

    Science.gov (United States)

    Aiken, C.; Peng, Z.; Douilly, R.; Calais, E.; Deschamps, A.; Haase, J. S.

    2013-05-01

    Tectonic tremors have been observed along major plate-boundary faults around the world. In most of these regions, tremors occur spontaneously (i.e. ambient) or as a result of small stress perturbations from passing surface waves (i.e. triggered). Because tremors are located below the seismogenic zone, a detailed study of their behavior could help to better understand how tectonic movement is accommodated in the deep root of major faults, and the relationship with large earthquakes. Here, we present evidence of triggered tremor in southern Haiti around the aftershock zone of the 2010/01/12 Mw7.0 Haiti earthquake. Following the January mainshock, several groups have installed land and ocean bottom seismometers to record aftershock activity (e.g., De Lepinay et al., 2011). In the following month, the 2010/02/27 Mw8.8 Maule, Chile earthquake occurred and was recorded in the southern Haiti region by these seismic stations. We apply a 5-15 Hz band-pass filter to all seismograms to identify local high-frequency signals during the Chile teleseismic waves. Tremor is identified as non-impulsive bursts with 10-20 s durations that is coherent among different stations and is modulated by surface waves. We also convert the seismic data into audible sounds and use them to distinguish between local aftershocks and deep tremor. We locate the source of the tremor bursts using an envelope cross-correlation method based on travel time differences. Because tremor depth is not well constrained with this method, we set it to 20 km, close to the recent estimate of Moho depth in this region (McNamara et al., 2012). Most tremors are located south of the surface expression of the Enriquillo-Plantain Garden Fault (EPGF), a high-angle southward dipping left-lateral strike-slip fault that marks the boundary between the Gonave microplate and the Caribbean plate, although the location errors are large. Tremor peaks are mostly modulated by Love wave velocity, which is consistent with left

  15. Infrasonic harmonic tremor and degassing bursts from Halema'uma'u Crater, Kilauea Volcano, Hawaii

    Science.gov (United States)

    Fee, David; Garcés, Milton; Patrick, Matt; Chouet, Bernard; Dawson, Phil; Swanson, Donald A.

    2010-01-01

    The formation, evolution, collapse, and subsequent resurrection of a vent within Halema'uma'u Crater, Kilauea Volcano, produced energetic and varied degassing signals recorded by a nearby infrasound array between 2008 and early 2009. After 25 years of quiescence, a vent-clearing explosive burst on 19 March 2008 produced a clear, complex acoustic signal. Near-continuous harmonic infrasonic tremor followed this burst until 4 December 2008, when a period of decreased degassing occurred. The tremor spectra suggest volume oscillation and reverberation of a shallow gas-filled cavity beneath the vent. The dominant tremor peak can be sustained through Helmholtz oscillations of the cavity, while the secondary tremor peak and overtones are interpreted assuming acoustic resonance. The dominant tremor frequency matches the oscillation frequency of the gas emanating from the vent observed by video. Tremor spectra and power are also correlated with cavity geometry and dynamics, with the cavity depth estimated at ~219 m and volume ~3 x 106 m3 in November 2008. Over 21 varied degassing bursts were observed with extended burst durations and frequency content consistent with a transient release of gas exciting the cavity into resonance. Correlation of infrasound with seismicity suggests an open system connecting the atmosphere to the seismic excitation process at depth. Numerous degassing bursts produced very long period (0.03-0.1 Hz) infrasound, the first recorded at Kilauea, indicative of long-duration atmospheric accelerations. Kilauea infrasound appears controlled by the exsolution of gas from the magma, and the interaction of this gas with the conduits and cavities confining it.

  16. Very Low Frequency Earthquakes (VLFEs) in Cascadia and Their Interactions with Tremor

    Science.gov (United States)

    Ghosh, A.

    2014-12-01

    Very low frequency earthquakes (VLFEs) are discrete seismic events rich in low frequencies (20 - 50 sec) and depleted in high frequencies compared to similar size local events. They are associated with slow earthquakes and so far found in only a handful of subduction zones worldwide. I systematically search and find VLFEs in the Cascadia subduction zone. I use a grid-search moment tensor inversion method to scan for VLFEs in 3-D space and time, locate them and determine their source parameters. They are located downdip of the locked zone, where non-volcanic tremor occurs (Fig. 1). The best estimates of VLFE depths put them near the plate interface. Their focal mechanisms indicate double couple sources and are consistent with shallow dipping thrust movement. Their moment magnitude ranges between 3.3 and 3.5 suggesting that a significant part of seismic moment may be released by such VLFEs during slow earthquakes. Interestingly, most of the VLFEs are located where the slip is the largest in an ETS event. Generally, VLFEs correlates with tremor quite well in space and time. They slowly migrate alongstrike form south to north with tremor. In detail, VLFEs appear to be tracking tremor even during tremor migration of shorter time scales. I am currently expanding the VLFE catalog in space and time to better characterize their spatiotemporal distribution, moment release, and their role in slow earthquakes. VLFEs and their interaction with tremor is providing new insights to the physics of slow earthquakes, underlying processes governing them and fault properties in Cascadia.

  17. The 2011 unrest at Katla volcano: Characterization and interpretation of the tremor sources

    Science.gov (United States)

    Sgattoni, Giulia; Gudmundsson, Ólafur; Einarsson, Páll; Lucchi, Federico; Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Tryggvason, Ari

    2017-05-01

    A 23-hour tremor burst was recorded on July 8-9th 2011 at the Katla subglacial volcano, one of the most active and hazardous volcanoes in Iceland. This was associated with deepening of cauldrons on the ice cap and a glacial flood that caused damage to infrastructure. Increased earthquake activity within the caldera started a few days before and lasted for months afterwards and new seismic activity started on the southern flank. No visible eruption broke the ice and the question arose as to whether this episode relates to a minor subglacial eruption with the tremor being generated by volcanic processes, or by the flood. The tremor signal consisted of bursts with varying amplitude and duration. We have identified and described three different tremor phases, based on amplitude and frequency features. A tremor phase associated with the flood was recorded only at stations closest to the river that flooded, correlating in time with rising water level observed at gauging stations. Using back-projection of double cross-correlations, two other phases have been located near the active ice cauldrons and are interpreted to be caused by volcanic or hydrothermal processes. The greatly increased seismicity and evidence of rapid melting of the glacier may be explained by a minor sub-glacial eruption. A less plausible interpretation is that the tremor was generated by hydrothermal boiling and/or explosions with no magma involved. This may have been induced by pressure drop triggered by the release of water when the glacial flood started. All interpretations require an increase of heat released by the volcano.

  18. The Dynamics of Voluntary Force Production in Afferented Muscle Influence Involuntary Tremor

    Directory of Open Access Journals (Sweden)

    Christopher M Laine

    2016-08-01

    Full Text Available Voluntary control of force is always marked by some degree of error and unsteadiness. Both neural and mechanical factors contribute to these fluctuations, but how they interact to produce them is poorly understood. In this study, we identify and characterize a previously undescribed neuromechanical interaction where the dynamics of voluntary force production suffice to generate involuntary tremor. Specifically, participants were asked to produce isometric force with the index finger and use visual feedback to track a sinusoidal target spanning 5 to 9 % of each individual’s maximal voluntary force level. Force fluctuations and EMG activity over the flexor digitorum superficialis (FDS muscle were recorded and their frequency content was analyzed as a function target phase. Force variability in either the 1 to 5 or 6 to 15 Hz frequency ranges tended to be largest at the peaks and valleys of the target sinusoid. In those same periods, FDS EMG activity was synchronized with force fluctuations. We then constructed a physiologically-realistic computer simulation in which a muscle-tendon complex was set inside of a feedback-driven control loop. Surprisingly, the model sufficed to produce phase-dependent modulation of tremor similar to that observed in humans. Further, the gain of afferent feedback from muscle spindles was critical for appropriately amplifying and shaping this tremor. We suggest that the experimentally-induced tremor may represent the response of a viscoelastic muscle-tendon system to dynamic drive, and therefore does not fall into known categories of tremor generation, such as tremorogenic descending drive, stretch-reflex loop oscillations, motor unit behavior, or mechanical resonance. Our findings motivate future efforts to understand tremor from a perspective that considers neuromechanical coupling within the context of closed-loop control. The strategy of combining experimental recordings with physiologically-sound simulations will

  19. Holmes’ Tremor with Shoulder Pain Treated by Deep Brain Stimulation of Unilateral Ventral Intermediate Thalamic Nucleus and Globus Pallidus Internus

    Directory of Open Access Journals (Sweden)

    Sabri Aydın

    2017-05-01

    Full Text Available A 21-year-old male was admitted with severe right arm and hand tremors after a thalamic hemorrhage caused by a traffic accident. He was also suffering from agonizing pain in his right shoulder that manifested after the tremor. Neurologic examination revealed a disabling, severe, and irregular kinetic and postural tremor in the right arm during target-directed movements. There was also an irregular ipsilateral rest tremor and dystonic movements in the distal part of the right arm. The amplitude was moderate at rest and extremely high during kinetic and intentional movements. The patient underwent left globus pallidum internus and ventral intermediate thalamic nucleus deep brain stimulation. The patient improved by more than 80% as rated by the Fahn-Tolosa-Marin Tremor Rating Scale and Visual Analog Scale six months after surgery.

  20. Head Impact Laboratory (HIL)

    Data.gov (United States)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  1. Episodic Muscle Tremors in a Quarter Horse: Resemblance to Hyperkalemic Periodic Paralysis

    OpenAIRE

    Steiss, Janet E.; Naylor, Jonathan M.

    1986-01-01

    A three year old Quarter Horse stallion was presented with a one year history of episodes of generalized muscle tremors and stiffness, and spasm of the muscles of facial expression, lasting 10-15 minutes. Between attacks, the horse was either normal or had a localized muscle tremor in the flank region. Episodes appeared unrelated to exercise. The major abnormal findings included 1) a rise in plasma potassium from a resting level of 4.4 to 7.9 mmol/L during an attack and 2) electromyographic f...

  2. Tremor Hypocenters Form a Narrow Zone at the Plate Interface in Two Areas of SW Japan

    Science.gov (United States)

    Armbruster, J. G.

    2015-12-01

    The tremor detectors developed for accurately locating tectonic tremor in Cascadia [Armbruster et al., JGR 2014] have been applied to data from the HINET seismic network in Japan. In the overview by Obara [Science 2002] there are three strong sources of tectonic tremor in southwest Japan: Shikoku, Kii Pen. and Tokai. The daily epicentral distributions of tremor on the HINET web site allow the identification of days when tremor in each source is active. The worst results were obtained in Shikoku, in spite of the high level of tremor activity observed there by others. This method requires a clear direct arrival of the S and P waves at the stations for coherence to be seen, so scattering and shear wave splitting are possible reasons for poor results there. Relatively wide station spacing, 19-30 km, is another possible reason. The best results were obtained in Tokai with stations STR, HRY and TYE spacing 18-19 km, and Kii Pen. with stations KRT, HYS and KAW spacing 15-22 km. In both of those areas the three station detectors see strong episodes of tremor. If detections with three stations are located by constraining them to the plate interface, a pattern of persistent sources is seen, with some intense sources. This is similar to what was seen in Cascadia. Detections with four stations give S and P arrival times of high accuracy. In Tokai the hypocenters form a narrow, 2-3 km thick, zone dipping to the north, consistent with the plate interface there. In Kii Pen. the hypocenters dip to the northwest in a thin, 2-3 km thick, zone but approximately 5 km shallower than a plate interface model for this area [Yoshioka and Murakami, GJI 2007]. The overlap of tremor sources in the 12 years analyzed here suggests relative hypocentral location errors as small as 2-3 km. We conclude that the methods developed in Cascadia will work in Japan but the typical spacing of HINET stations, ~20 km, is greater than the optimum distance found in analysis of data from Cascadia, 8 to 15 km.

  3. Study of Tectonic Tremor in Depth: Triggering Stress Observation and Model of the Triggering Mechanism

    Science.gov (United States)

    Wang, Tien-Huei

    Non-volcanic tremor (NVT) has been discovered in recent years due to advances in seismic instruments and increased density of seismic networks. The NVT is a special kind of seismic signal indicative of the physical conditions and the failure mechanism on the source on the fault where NVT occurs. The detection methods used and the sensitivity of them relies on the density, distance and instrumentation of the station network available. How accurately the tremor is identified in different regions varies greatly among different studies. Therefore, there has not been study that rigorously documents tectonic tremors in different regions under limited methods and data. Meanwhile, many incidences of NVTs are observed during or after small but significant strain change induced by teleseismic, regional or local earthquake. The understanding of the triggering mechanisms critical for tremor remains unclear. In addition, characteristics of the triggering of NVT in different regions are rarely compared because of the short time frame after the discovery of the triggered NVTs. We first explore tectonic tremor based on observations to learn about its triggering, frequency of occurrence, location and spectral characteristics. Then, we numerically model the triggering of instability on the estimated tremor-source, under assumptions fine-tuned according to previous studies (Thomas et al., 2009; Miyazawa et al., 2005; Hill, 2008; Ito, 2009; Rubinstein et al., 2007; Peng and Chao, 2008). The onset of the slip reveals that how and when the external loading triggers tremor. It also holds the information to the background stress conditions under which tremor source starts with. We observe and detect tremor in two regions: Anza and Cholame, along San Jacinto Fault (SJF) and San Andreas Fault (SAF) respectively. These two sections of the faults, relative to general fault zone on which general earthquakes occur, are considered transition zones where slip of slow rates occurs. Slip events

  4. Expectation modulates the effect of deep brain stimulation on motor and cognitive function in tremor-dominant Parkinson's disease.

    Science.gov (United States)

    Keitel, Ariane; Ferrea, Stefano; Südmeyer, Martin; Schnitzler, Alfons; Wojtecki, Lars

    2013-01-01

    Expectation contributes to placebo and nocebo responses in Parkinson's disease (PD). While there is evidence for expectation-induced modulations of bradykinesia, little is known about the impact of expectation on resting tremor. Subthalamic nucleus (STN) deep brain stimulation (DBS) improves cardinal PD motor symptoms including tremor whereas impairment of verbal fluency (VF) has been observed as a potential side-effect. Here we investigated how expectation modulates the effect of STN-DBS on resting tremor and its interaction with VF. In a within-subject-design, expectation of 24 tremor-dominant PD patients regarding the impact of STN-DBS on motor symptoms was manipulated by verbal suggestions (positive [placebo], negative [nocebo], neutral [control]). Patients participated with (MedON) and without (MedOFF) antiparkinsonian medication. Resting tremor was recorded by accelerometry and bradykinesia of finger tapping and diadochokinesia were assessed by a 3D ultrasound motion detection system. VF was quantified by lexical and semantic tests. In a subgroup of patients, the effect of STN-DBS on tremor was modulated by expectation, i.e. tremor decreased (placebo response) or increased (nocebo response) by at least 10% as compared to the control condition while no significant effect was observed for the overall group. Interestingly, nocebo responders in MedON were additionally characterized by significant impairment in semantic verbal fluency. In contrast, bradykinesia was not affected by expectation. These results indicate that the therapeutic effect of STN-DBS on tremor can be modulated by expectation in a subgroup of patients and suggests that tremor is also among the parkinsonian symptoms responsive to placebo and nocebo interventions. While positive expectations enhanced the effect of STN-DBS by further decreasing the magnitude of tremor, negative expectations counteracted the therapeutic effect and at the same time exacerbated a side-effect often associated with STN

  5. Expectation modulates the effect of deep brain stimulation on motor and cognitive function in tremor-dominant Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Ariane Keitel

    Full Text Available Expectation contributes to placebo and nocebo responses in Parkinson's disease (PD. While there is evidence for expectation-induced modulations of bradykinesia, little is known about the impact of expectation on resting tremor. Subthalamic nucleus (STN deep brain stimulation (DBS improves cardinal PD motor symptoms including tremor whereas impairment of verbal fluency (VF has been observed as a potential side-effect. Here we investigated how expectation modulates the effect of STN-DBS on resting tremor and its interaction with VF. In a within-subject-design, expectation of 24 tremor-dominant PD patients regarding the impact of STN-DBS on motor symptoms was manipulated by verbal suggestions (positive [placebo], negative [nocebo], neutral [control]. Patients participated with (MedON and without (MedOFF antiparkinsonian medication. Resting tremor was recorded by accelerometry and bradykinesia of finger tapping and diadochokinesia were assessed by a 3D ultrasound motion detection system. VF was quantified by lexical and semantic tests. In a subgroup of patients, the effect of STN-DBS on tremor was modulated by expectation, i.e. tremor decreased (placebo response or increased (nocebo response by at least 10% as compared to the control condition while no significant effect was observed for the overall group. Interestingly, nocebo responders in MedON were additionally characterized by significant impairment in semantic verbal fluency. In contrast, bradykinesia was not affected by expectation. These results indicate that the therapeutic effect of STN-DBS on tremor can be modulated by expectation in a subgroup of patients and suggests that tremor is also among the parkinsonian symptoms responsive to placebo and nocebo interventions. While positive expectations enhanced the effect of STN-DBS by further decreasing the magnitude of tremor, negative expectations counteracted the therapeutic effect and at the same time exacerbated a side-effect often

  6. Heading and head injuries in soccer.

    Science.gov (United States)

    Kirkendall, D T; Jordan, S E; Garrett, W E

    2001-01-01

    In the world of sports, soccer is unique because of the purposeful use of the unprotected head for controlling and advancing the ball. This skill obviously places the player at risk of head injury and the game does carry some risk. Head injury can be a result of contact of the head with another head (or other body parts), ground, goal post, other unknown objects or even the ball. Such impacts can lead to contusions, fractures, eye injuries, concussions or even, in rare cases, death. Coaches, players, parents and physicians are rightly concerned about the risk of head injury in soccer. Current research shows that selected soccer players have some degree of cognitive dysfunction. It is important to determine the reasons behind such deficits. Purposeful heading has been blamed, but a closer look at the studies that focus on heading has revealed methodological concerns that question the validity of blaming purposeful heading of the ball. The player's history and age (did they play when the ball was leather and could absorb significant amounts of water), alcohol intake, drug intake, learning disabilities, concussion definition and control group use/composition are all factors that cloud the ability to blame purposeful heading. What does seem clear is that a player's history of concussive episodes is a more likely explanation for cognitive deficits. While it is likely that the subconcussive impact of purposeful heading is a doubtful factor in the noted deficits, it is unknown whether multiple subconcussive impacts might have some lingering effects. In addition, it is unknown whether the noted deficits have any affect on daily life. Proper instruction in the technique is critical because if the ball contacts an unprepared head (as in accidental head-ball contacts), the potential for serious injury is possible. To further our understanding of the relationship of heading, head injury and cognitive deficits, we need to: learn more about the actual impact of a ball on the

  7. Imaging Slow Slip Fronts in Cascadia With High-Precision Tremor Locations

    Science.gov (United States)

    Rubin, A. M.; Armbruster, J. G.

    2012-12-01

    We use the method of Armbruster and Kim [AGU 2010] to obtain tremor locations using 4-second windows, focusing on a few spots beneath southern Vancouver Island activated by slow slip events from 2003 to 2005. The method compares horizontal-component waveforms (not envelopes) at 3 stations separated by 10-20 km. From local earthquakes "caught" by the detector it appears that the coherent signal consists of the direct S arrival but not the S coda. Using 150-s windows, Armbruster and Kim found "wispy" sources of tremor that in some regions were reproducible between the 2003, 2004, and 2005 events to within 1 km. In time, their tremor locations trace out quasi-linear trajectories on the fault surface that migrate tens of times faster than the main front, as has been reported elsewhere [e.g., Ghosh et al., 2010; Vidale et al., AGU 2011]. By moving to 4-s windows, we find that these long-time-window locations very often represent the spatial "average" of secondary fronts behind the main front. These secondary fronts tend to (a) start within about 1 km of the main tremor front and propagate back along strike, akin to the "rapid tremor reversals" of Houston et al. [2011] but on a smaller scale (5 km rather than 50); (b) less commonly do the reverse, ending at the main front; or (c) propagate up- or down-dip at or within 1-2 kilometers of the main front. Rare events propagate in other directions. The fronts that move along strike can be as narrow as 1 km in the propagation direction but can exceed 5 km in the orthogonal direction. Those that propagate along dip are typically also narrow (~ 1 km) in the strike direction; if they are even narrower in the propagation direction this is below our resolution. Characteristic propagation speeds are 10 km/hr along strike and several times faster along dip. For those along-dip migrations that occur at the main front, the larger propagation speed is plausibly an "apparent" velocity as the main front intersects an along-dip alignment

  8. Identification of a Divergent Lineage Porcine Pestivirus in Nursing Piglets with Congenital Tremors and Reproduction of Disease following Experimental Inoculation.

    Directory of Open Access Journals (Sweden)

    Bailey L Arruda

    Full Text Available Congenital tremors is a sporadic disease of neonatal pigs characterized by action-related repetitive myoclonus. A majority of outbreaks of congenital tremors have been attributed to an unidentified virus. The objectives of this project were to 1 detect potential pathogen(s in samples from piglets with congenital tremors and 2 develop an infection model to reproduce disease. Using next-generation sequencing, a divergent lineage pestivirus was detected in piglets with congenital tremors. The virus was originally most closely related to a bat pestivirus but is now more closely related to a recently published novel porcine pestivirus provisionally named atypical porcine pestivirus. A quantitative real-time PCR detected the virus in samples from neonatal piglets with congenital tremors from two separate farms, but not in samples from unaffected piglets from the same farm. To fulfill the second objective, pregnant sows were inoculated with either serum containing the pestivirus or PBS (control by intravenous and intranasal routes simultaneously with direct inoculation of fetal amniotic vesicles by ultrasound-guided surgical technique. Inoculations were performed at either 45 or 62 days of gestation. All sows inoculated with the novel pestivirus farrowed piglets affected with congenital tremors while PBS-inoculated control piglets were unaffected. Tremor severity for each piglet was scored from videos taken 0, 1 and 2 days post-farrowing. Tremor severity remained relatively constant from 0 to 2 days post-farrowing for a majority of piglets. The prevalence of congenital tremors in pestivirus-inoculated litters ranged from 57% (4 out of 7 affected piglets to 100% (10 out of 10 affected piglets. The virus was consistently detected by PCR in tissues from piglets with congenital tremors but was not detected in control piglets. Samples positive by PCR in greater than 90% of piglets sampled included brainstem (37 out of 41, mesenteric lymph node (37 out of 41

  9. Tremor Reduction at the Palm of a Parkinson’s Patient Using Dynamic Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Sarah Gebai

    2016-07-01

    Full Text Available Parkinson’s patients suffer from severe tremor due to an abnormality in their central oscillator. Medications used to decrease involuntary antagonistic muscles contraction can threaten their life. However, mechanical vibration absorbers can be used as an alternative treatment. The objective of this study is to provide a dynamic modeling of the human hand that describes the biodynamic response of Parkinson’s patients and to design an effective tuned vibration absorber able to suppress their pathological tremor. The hand is modeled as a three degrees-of-freedom (DOF system describing the flexion motion at the proximal joints on the horizontal plane. Resting tremor is modeled as dual harmonic excitation due to shoulder and elbow muscle activation operating at resonance frequencies. The performance of the single dynamic vibration absorber (DVA is studied when attached to the forearm and compared with the dual DVA tuned at both excitation frequencies. Equations of motion are derived and solved using the complex transfer function of the non-Lagrangian system. The absorber’s systems are designed as a stainless steel alloy cantilevered beam with an attached copper mass. The dual DVA was the most efficient absorber which reduces 98.3%–99.5%, 97.0%–97.3% and 97.4%–97.5% of the Parkinson’s tremor amplitude at the shoulder, elbow and wrist joint.

  10. The timing of primary orthostatic tremor bursts has a task-specific plasticity.

    Science.gov (United States)

    McAuley, J H; Britton, T C; Rothwell, J C; Findley, L J; Marsden, C D

    2000-02-01

    Primary orthostatic tremor is characterized by unsteadiness and shakiness of the legs while standing. It is due to a remarkably strong and regular EMG modulation at approximately 16 Hz that is thought to be of CNS origin. Previous studies have shown that the tremor frequency is the same in all involved muscles and that the time relation between bursts of activity in different muscles may be fixed (e.g. always co-contracting or always contracting in an alternating pattern). Here we have used frequency domain analysis of postural muscle EMG signals in five primary orthostatic tremor patients and in two normal controls to explore the nature of such fixed timing patterns. The timing is found not to relate simply to the relative conduction times for passage of rhythmic bursts from a central oscillation to different muscles. Indeed, although the timing pattern (expressed as phase) of the 16-Hz EMG bursts in different postural muscles remains constant while the subject adopts a certain steady posture, it is different for different subjects and also changes when the same subject adopts a different posture. It seems unlikely that such complex task-dependent timing relations of rhythmic postural muscle activity are due to the primary pathology of primary orthostatic tremor. Instead, we suggest that the abnormally strong peripheral manifestation of a 16-Hz CNS oscillation merely unmasks normal central processes so that the timing patterns may provide a clue to the nature of postural motor control.

  11. Volcanic tremor at Mt Vesuvius associated with low frequency shear failures

    Science.gov (United States)

    La Rocca, Mario; Galluzzo, Danilo

    2016-05-01

    Mt Vesuvius has been dormant since the eruption occurred in 1944, after which the conduit closed and the volcano entered a quiescent state. Only a minor seismic activity, characterized by low magnitude volcano-tectonic (VT) earthquakes, testifies that the magmatic system is still active. In this paper we report the fist quantitative analysis of volcanic tremor discovered at Vesuvius through the analysis of array data. A seismic array installed in 2012 improved the monitoring performance of the local network, permitting the identification of low amplitude coherent signals. Many of such coherent signals recorded during the last few years have been classified as volcanic tremor. We selected 22 tremor events based on their amplitude and on the number of available stations, and performed detailed analysis aimed at location and characterization of the source. They are characterized by low frequency, duration of a few minutes, and the strongest episodes are recorded at distance up to 90 km from the volcano. In many cases we could identify P-S wave pairs in the seismograms that allowed a precise location of the source depth, which is in the range between 5 km and 6.5 km below the crater. Waveform features, spectral analysis, and comparison with VT earthquakes located at the same depth indicate that the source mechanism of the Vesuvius non-eruptive tremor is a sequence of low frequency shear failures.

  12. Cessação tabágica em paciente com tremor essencial

    Directory of Open Access Journals (Sweden)

    Carolina Ferreira da Costa

    2013-01-01

    Full Text Available Existem pacientes que, apesar dos esforços da equipe do programa de cessação tabágica, mostram-se refratários à redução do tabagismo. Entre os motivos mais citados para isso, estão abuso de álcool, ansiedade e depressão. Além desses, o tremor essencial, frequentemente negligenciado pelos pacientes e médicos, tem implicações clínicas diretas e indiretas para aqueles que desejam parar de fumar. Antes entendida como uma doença benigna, o tremor essencial tem fortes associações com transtornos psiquiátricos, além de piorar com a abstinência de nicotina e com o uso de determinados medicamentos para a cessação. Descrevemos um caso de tremor essencial e comorbidades psiquiátricas no seu percurso para a abstinência tabágica. Com relação à associação entre nicotina e o curso do tremor essencial, maiores estudos são necessários. Mas diagnosticar sua presença apresenta relevância clínica, podendo ser um marcador de pior prognóstico para a cessação.

  13. Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

    Energy Technology Data Exchange (ETDEWEB)

    Hesselmann, Volker; Schaaf, Maike; Krug, Barbara; Lackner, Klaus [University of Cologne, Department of Radiology, Cologne (Germany); Maarouf, Mohammed; Hunsche, Stefan; Sturm, Volker [University of Cologne, Department of Stereotaxy and Functional Neurosurgery, Cologne (Germany); Lasek, Kathrin [Universitaetsklinikum Schleswig Holstein, Klinik fuer Neurologie, Luebeck (Germany); Wedekind, Christoph [Akademisches Lehrkrankenhaus der Universitaet Erlangen-Nuernberg, Belegabteilung fuer Neurochirurgie, Klinikum Bamberg, Bamberg (Germany)

    2006-10-15

    The effect of stereotactic thalamotomy was assessed with pre- and postoperative functional magnetic resonance imaging (fMRI) under motor stimulation. A patient with unilateral essential tremor (ET) of the left arm underwent stereotactically guided thalamotomy of the right ventral intermediate thalamic nucleus (VIM). FMRI was done directly before and after surgery on a 1.5-Tesla scanner. The stimulation paradigm was maintainance of the affected arm in an extended position and hand clenching being performed in a block design manner. Statistical analysis was done with Brain Voyager 2000. After thalamotomy the tremor diminished completely. As a difference between the pre- and postoperative fMRI, a significant activation was found in the VIM contralateral to the activation site, adjacent to the inferior olivary nucleus contralateral to the activation site and in the dorsal cingulum. In conclusion, fMRI can detect the functional effect of thalamotomy for tremor treatment. Direct postoperative fMRI provides a sufficient method for estimating the effect of thalamotomy immediately after intervention. The importance of the intermediate thalamic nucleus and the olivary nucleus in tremor generation is supported by our findings. (orig.)

  14. Seismic Tremor Generated by Multiple Processes, Vatnajökull Glacier, Iceland

    Science.gov (United States)

    Eibl, E. P. S.; Bean, C. J.; Vogfjord, K. S.

    2014-12-01

    Vatnajökull glacier in eastern Iceland covers five volcanic systems in which Bárdarbunga and Grimsvötn are the most active volcanoes. Whilst fluctuating ice cover mitigates against year-round near-field monitoring of the volcanoes, important information can be gleaned from stations deployed at the glacier's edge. Glacial cover significantly increases the complexity of and the solution space for observed seismic signals. For example tremor can be caused by magmatic activity, intra-glacier interactions, melt water flow or hydrothermal boiling. A better understanding of hazard requires a more indepth understanding of the signals generated by these processes at Vatnajökull. We augmented the sparse network in the region with two seven-element broad band seismometer arrays west of Vatnajökull, in Jökulheimar and near Laki respectively. Observed seismic tremor-like transients (< 2 Hz) originating from two cauldrons west of Grimsvötn are directly associated with small flooding events (jökulhaups), as subsequently confirmed by radar and hydrological observations. For larger longer duration floods dominant harmonic tremor frequencies of 2 to 4 Hz are observed, but they change in amplitude and frequency with time, likely reflecting variable feed and flow rates, associated with a moving source. Our aim is to 'fingerprint' these events such that they can be distinguished from seismic tremor signals associated with magmatic activity.

  15. Detection of tremor bursts by a running second order moment function and analysis using interburst histograms

    NARCIS (Netherlands)

    Journee, Henricus Louis; Postma, Alida Annechien; Sun, Mingui; Staal, Michiel J.

    2008-01-01

    Introduction: Conventional linear signal processing techniques are not always suitable for the detection of tremor bursts in clinical practice due to inevitable noise from electromyographic (EMG) bursts. This study introduces (1) a non-linear analysis technique based on a running second order moment

  16. INFLUENCE OF VISUAL FEEDBACK ON HUMAN ISOMETRIC BITE-FORCE TREMOR

    NARCIS (Netherlands)

    BROEKHUIJSEN, ML; VANWILLIGEN, JD

    1994-01-01

    In contrast to recent reports, during an isometric short forceful bite, visual feedback had a significant influence on the force tremor spectrum. The value of a 'half-value frequency', being the frequency f1/2 at which, with increasing frequency, the amplitude of the spectrum for the first time drop

  17. Episodic Muscle Tremors in a Quarter Horse: Resemblance to Hyperkalemic Periodic Paralysis

    Science.gov (United States)

    Steiss, Janet E.; Naylor, Jonathan M.

    1986-01-01

    A three year old Quarter Horse stallion was presented with a one year history of episodes of generalized muscle tremors and stiffness, and spasm of the muscles of facial expression, lasting 10-15 minutes. Between attacks, the horse was either normal or had a localized muscle tremor in the flank region. Episodes appeared unrelated to exercise. The major abnormal findings included 1) a rise in plasma potassium from a resting level of 4.4 to 7.9 mmol/L during an attack and 2) electromyographic findings of generalized increased insertion activity and myotonic discharges. The horse was treated with hydrochlorothiazide tablets for nine months, during which time no further attacks were noted. However, four months after the drug was stopped, sporadic focal muscle tremors reappeared; two months later, generalized attacks were seen. Despite reinstitution of the diuretic, a focal flank tremor persisted. Two related horses in the same stable also were reported by the owner to exhibit sporadic generalized muscle twitching. The abnormal findings of the present case differ from clinical syndromes previously reported in horses. Some similarities to hyperkalemic periodic paralysis in humans are noted. PMID:17422693

  18. The fragile X-associated tremor ataxia syndrome (FXTAS) in Indonesia

    NARCIS (Netherlands)

    Winarni, T.I.; Mundhofir, F.E.P.; Ediati, A.; Belladona, M.; Nillesen, W.M.; Yntema, H.G.; Hamel, B.C.J.; Faradz, S.M.H.; Hagerman, R.J.

    2013-01-01

    Fragile X-associated disorders caused by the premutation of the FMR1 gene, includes the fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS affects more than 40% of premutation males over the age of 50 and 75% over the age of 80. FMR1 molecular analysis was done using PCR and confirmed by Sou

  19. Tremor Reduction by Deep Brain Stimulation Is Associated With Gamma Power Suppression in Parkinson's Disease

    NARCIS (Netherlands)

    Beudel, Martijn; Little, Simon; Pogosyan, Alek; Ashkan, Keyoumars; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Bogdanovic, Marko; Cheeran, Binith; Green, Alexander L.; Aziz, Tipu; Thevathasan, Wesley; Brown, Peter

    2015-01-01

    Objectives: Rest tremor is a cardinal symptom of Parkinson's disease (PD), and is readily suppressed by deep brain stimulation (DBS) of the subthalamic nucleus (STN). The therapeutic effect of the latter on bradykinesia and rigidity has been associated with the suppression of exaggerated beta (13-30

  20. A Postural Tremor Highly Responsive to Transcranial Cerebello-Cerebral DCS in ARCA3.

    Science.gov (United States)

    Bodranghien, Florian; Oulad Ben Taib, Nordeyn; Van Maldergem, Lionel; Manto, Mario

    2017-01-01

    Cerebellar ataxias are disabling disorders that impact the quality of life of patients. In many cases, an effective treatment is missing. Despite the increasing knowledge on the pathogenesis of cerebellar disorders including genetic aspects, there is currently a gap in the therapeutical management of cerebellar deficits. Cerebellar ataxia associated with ANO10 mutation (ARCA3) presents a disabling cerebellar syndrome. The aim of this study is to report a patient with a marked postural tremor responding to transcranial cerebello-cerebral direct current stimulation (tCCDCS). We applied tCCDCS using anodal stimulation over the cerebellum with a return electrode on the contralateral motor cortex. We performed a clinical rating, accelerometry studies, and recordings of voluntary movements at baseline, after sham, and after active tCCDCS. A dramatic response of postural tremor was observed after tCCDCS, with a major drop of the power spectral density to 26.12% of basal values. The postural tremor of cerebellar ataxia associated with ANO10 mutation was highly responsive to tCCDCS in our patient. This case illustrates that tCCDCS is a novel therapeutic option in the treatment of cerebellar deficits and might represent a promising tool to reduce tremor in ARCA3.

  1. GABA(A) receptor- and GABA transporter polymorphisms and risk for essential tremor

    DEFF Research Database (Denmark)

    Thier, S; Kuhlenbäumer, G; Lorenz, D

    2011-01-01

    Background:  Clinical features and animal models of essential tremor (ET) suggest gamma-aminobutyric acid A receptor (GABA(A) R) subunits and GABA transporters as putative candidate genes. Methods:  A total of 503 ET cases and 818 controls were investigated for an association between polymorphisms...

  2. Polymorphisms in the glial glutamate transporter SLC1A2 are associated with essential tremor

    DEFF Research Database (Denmark)

    Thier, Sandra; Lorenz, Delia; Nothnagel, Michael

    2012-01-01

    Sporadic, genetically complex essential tremor (ET) is one of the most common movement disorders and may lead to severe impairment of the quality of life. Despite high heritability, the genetic determinants of ET are largely unknown. We performed the second genome-wide association study (GWAS...

  3. Tremor side effects of salbutamol, quantified by a laser pointer technique.

    NARCIS (Netherlands)

    Nizet, T.; Broeders, M.E.A.C.; Folgering, H.T.M.

    2004-01-01

    OBJECTIVE: To study tremor side effects of salbutamol an easily applicable, quick and low-priced method is needed. A new method using a commercially available, pen-shaped laser pointer was developed. Aim of the study was to determine sensitivity, reproducibility, reference values and the agreement w

  4. INFLUENCE OF VISUAL FEEDBACK ON HUMAN ISOMETRIC BITE-FORCE TREMOR

    NARCIS (Netherlands)

    BROEKHUIJSEN, ML; VANWILLIGEN, JD

    1994-01-01

    In contrast to recent reports, during an isometric short forceful bite, visual feedback had a significant influence on the force tremor spectrum. The value of a 'half-value frequency', being the frequency f1/2 at which, with increasing frequency, the amplitude of the spectrum for the first time drop

  5. A comparison of calcium antagonists and diazepam in reducing ethanol withdrawal tremors.

    Science.gov (United States)

    Bone, G H; Majchrowicz, E; Martin, P R; Linnoila, M; Nutt, D J

    1989-01-01

    The calcium antagonists nimodipine and dantrolene were compared with diazepam in an animal model of tolerance and physical dependence upon ethanol. Nimodipine and dantrolene were both effective in suppressing withdrawal tremors but diazepam was clearly superior to both agents. These results suggest that the ethanol withdrawal syndrome is only partially mediated by increased calcium flux.

  6. Alarm systems detect volcanic tremor and earthquake swarms during Redoubt eruption, 2009

    Science.gov (United States)

    Thompson, G.; West, M. E.

    2009-12-01

    We ran two alarm algorithms on real-time data from Redoubt volcano during the 2009 crisis. The first algorithm was designed to detect escalations in continuous seismicity (tremor). This is implemented within an application called IceWeb which computes reduced displacement, and produces plots of reduced displacement and spectrograms linked to the Alaska Volcano Observatory internal webpage every 10 minutes. Reduced displacement is a measure of the amplitude of volcanic tremor, and is computed by applying a geometrical spreading correction to a displacement seismogram. When the reduced displacement at multiple stations exceeds pre-defined thresholds and there has been a factor of 3 increase in reduced displacement over the previous hour, a tremor alarm is declared. The second algorithm was to designed to detect earthquake swarms. The mean and median event rates are computed every 5 minutes based on the last hour of data from a real-time event catalog. By comparing these with thresholds, three swarm alarm conditions can be declared: a new swarm, an escalation in a swarm, and the end of a swarm. The end of swarm alarm is important as it may mark a transition from swarm to continuous tremor. Alarms from both systems were dispatched using a generic alarm management system which implements a call-down list, allowing observatory scientists to be called in sequence until someone acknowledged the alarm via a confirmation web page. The results of this simple approach are encouraging. The tremor alarm algorithm detected 26 of the 27 explosive eruptions that occurred from 23 March - 4 April. The swarm alarm algorithm detected all five of the main volcanic earthquake swarm episodes which occurred during the Redoubt crisis on 26-27 February, 21-23 March, 26 March, 2-4 April and 3-7 May. The end-of-swarm alarms on 23 March and 4 April were particularly helpful as they were caused by transitions from swarm to tremor shortly preceding explosive eruptions; transitions which were

  7. A geological perspective on the source(s) of slow slip and tremor

    Science.gov (United States)

    Fagereng, Ake

    2016-04-01

    Slow slip events (SSEs) represent transient fault slip velocities slower than earthquakes but faster than steady, average plate motion. SSEs are detected geodetically and do not emit detectable seismic waves, although they are commonly, but not always, accompanied by tectonic tremor. Tremor is defined as persistent, low-frequency (waves. Within the tremor signal are low and very low frequency earthquakes, interpreted as shear slip on faults subparallel to, and kinematically consistent with, the hosting fault. An increasingly common interpretation is that SSEs are a form of transient fault creep, and associated low frequency seismic phenomena represent shear failure of asperities embedded in the creeping fault segment. A geological analogue to the coupled phenomena of slow slip and tremor is then a brittle-ductile shear zone where frictional failure occurs in scattered locations within a dominantly viscous matrix. Where slow slip and tremor spatially and temporally coincide, the total seismic moment of tremor and superimposed low frequency seismic events is negligible compared to the geodetic moment of the SSE. Thus, the geological analogue is restricted to brittle-ductile shear zones where the majority of finite strain is accommodated by ductile deformation. Also, the geodetic moment of an SSE is representative of the elastic strain in the rock volume surrounding the fault, that is converted to finite fault zone displacement by the SSE (centimetres), whereas tremor represents coincident frictional failure with small (sub-mm) slip magnitudes. This interpretation assumes that SSEs, like earthquakes, represent a form of stick-slip motion associated with elastic strain build-up and release in the surrounding elastic rock volume. If this assumption is correct, and geological analogues implying SSEs may form by viscous shearing flow are also correct, then SSE source parameters can be considered in terms of viscous deformation of a tabular shear zone. Analogous to

  8. Geodetic And Seismic Signatures of Episodic Tremor And Slip Beneath Vancouver Island, British Columbia.

    Science.gov (United States)

    Dragert, H.; Rogers, G.; Wang, K.

    2004-05-01

    Slip events with an average duration of about 10 days and effective total slip displacements of several centimetres have been detected on the deeper (25 to 45 km) part of the northern Cascadia subduction zone plate interface by a network of continuously recording Global Positioning System (GPS) sites. The slip events occur down-dip from the currently locked, seismogenic portion of the plate interface, and, for the geographic region around Victoria, British Columbia, repeat at 13 to 16 month intervals. These episodes of slip are accompanied by distinct, low frequency, non-earthquake tremors, similar to those reported in the forearc region of southern Japan, prompting the naming of this phenomenon as Episodic Tremor and Slip (ETS). The tremor-like seismic signals have now been identified beneath most of Vancouver Island. For northern Vancouver Island, where plate convergence is at a much slower rate, return periods of about 14 months were also observed for significant (duration exceeding 7 days) tremor sequences, but about 6 months out of phase with southern Vancouver Island. Slip associated with northern island tremors has not been resolved clearly enough to allow modeling because of sparse GPS coverage, but 3 to 4 mm surface displacements coincident with the most recent tremors were observed at two newer GPS stations located on the northwest coast of Vancouver Island. The total amount of tremor activity, and by inference slip activity, appears to be the same in northern and southern Vancouver Island and therefore independent of plate convergence rate. ETS activity is observed to migrate along the strike of the subduction zone at speeds of 5 to 15 km/day and this migration does not appear to be impeded by the Nootka Fault Zone that marks the change in subduction rates. It is strongly suspected that the youth of the subducting plate and the release of fluids from slab dehydration are key factors contributing to the episodic, semi-brittle behaviour of the ETS zone. It

  9. Mitochondrial serine protease HTRA2 p.G399S in a kindred with essential tremor and Parkinson disease.

    Science.gov (United States)

    Unal Gulsuner, Hilal; Gulsuner, Suleyman; Mercan, Fatma Nazli; Onat, Onur Emre; Walsh, Tom; Shahin, Hashem; Lee, Ming K; Dogu, Okan; Kansu, Tulay; Topaloglu, Haluk; Elibol, Bulent; Akbostanci, Cenk; King, Mary-Claire; Ozcelik, Tayfun; Tekinay, Ayse B

    2014-12-23

    Essential tremor is one of the most frequent movement disorders of humans and can be associated with substantial disability. Some but not all persons with essential tremor develop signs of Parkinson disease, and the relationship between the conditions has not been clear. In a six-generation consanguineous Turkish kindred with both essential tremor and Parkinson disease, we carried out whole exome sequencing and pedigree analysis, identifying HTRA2 p.G399S as the allele likely responsible for both conditions. Essential tremor was present in persons either heterozygous or homozygous for this allele. Homozygosity was associated with earlier age at onset of tremor (P Parkinson signs in the middle age. Among population controls from the same Anatolian region as the family, frequency of HTRA2 p.G399S was 0.0027, slightly lower than other populations. HTRA2 encodes a mitochondrial serine protease. Loss of function of HtrA2 was previously shown to lead to parkinsonian features in motor neuron degeneration (mnd2) mice. HTRA2 p.G399S was previously shown to lead to mitochondrial dysfunction, altered mitochondrial morphology, and decreased protease activity, but epidemiologic studies of an association between HTRA2 and Parkinson disease yielded conflicting results. Our results suggest that in some families, HTRA2 p.G399S is responsible for hereditary essential tremor and that homozygotes for this allele develop Parkinson disease. This hypothesis has implications for understanding the pathogenesis of essential tremor and its relationship to Parkinson disease.

  10. Shallow micro low-frequency tremor before the Tohoku-Oki earthquake

    Science.gov (United States)

    Katakami, Satoshi; Ito, Yoshihiro; Ohta, Kazuaki; Hino, Ryota; Suzuki, Syuichi; Shinohara, Masanao

    2017-04-01

    Slow earthquake activity is one of the important phenomena to understand slip behavior in the shallower part of the subduction zone, especially to understand the generation of tsunami earthquakes. Recently, SSEs and low-frequency tremor have been observed near the trench by using ocean bottom observations, and these have been located in the updip portion of a coseismic slip area [Wallace et al., 2016; Yamashita et al., 2015]. In addition, Ito et al. [2015] observed tremor sequences from the excitation of ambient noise amplitude, accompanied with SSE in the source area of the Tohoku-Oki earthquake's mainshock. However, the signals observed within these sequences showed very weak amplitude and were observed at only one station, nearest to the Japan Trench. Here, we report on our detection of micro low-frequency tectonic tremor (mLFT) activity prior to the 2011 Tohoku-Oki earthquake near the Japan Trench by using modified frequency scanning method (mFSM) as applied to ocean bottom seismometers (OBSs) . The original frequency scanning method [Sit et al., 2012] proposed a tremor detection method of calculating envelope waveform ratios through different bandpass filters of broadband data in the Cascadia margin. We modified this analysis for short period OBS seismic data recorded at 17 OBSs deployed in an area near the trench axis offshore Miyagi Prefecture, northeast Japan. Three bandpass filters of 2-4 Hz, 10-20 Hz, and 0.5-1.0 Hz, corresponding to the dominant frequency band of tremors, local earthquakes, and ocean noise, respectively, were applied to the OBS records for a period between November 19, 2010 and March 9, 2011. This duration is the same as the deployment period of TJT2 station which is located nearest to the Japan Trench, and is also before the largest foreshock of the Tohoku-Oki earthquake. The results of applying the mFSM show three major tremor sequences, suggesting tremor activity in the shallowest part of the subduction zone. The sequences agree with

  11. Characteristics of hand tremor and postural sway in patients with fetal-type Minamata disease.

    Science.gov (United States)

    Iwata, Toyoto; Takaoka, Shigeru; Sakamoto, Mineshi; Maeda, Eri; Nakamura, Masaaki; Liu, Xiao-Jie; Murata, Katsuyuki

    2016-01-01

    About forty certified patients aged around 50 years old existed as living witnesses to fetal-type Minamata disease (methylmercury poisoning due to in utero exposure) in Minamata, Japan in 2006. Computerized hand tremor and postural sway tests with spectral analysis were conducted for 24 of them and in matched control subjects to examine the pathophysiological feature of neuromotor function. The tremor intensities of the patients with fetal-type Minamata disease were significantly larger than those of the 67 controls at every frequency band for both hands. In the patients, proportions for intensity at 1-6 Hz of both hands were larger, but those of the intensity at 6-10 Hz were smaller compared with the controls. The center frequency of a tremor was significantly lower in the patients than in the controls. Only eight males of the 24 patients were examined to evaluate postural sway because of extremely low scores in activities of daily living in the remaining. Most of the postural sway parameters obtained with eyes open and closed were significantly larger in the patients than in the male controls. Likewise, Romberg quotients of postural sway in anterior-posterior direction were significantly higher in the patients. In conclusion, the patients with fetal-type Minamata disease of our study showed a larger tremor of low frequency at less than 6 Hz and postural instability. Spectral analyses of computerized hand tremor and postural sway are suggested to be useful for assessing the pathophysiological change, related to a lesion of the cerebellum, resulting from prenatal methylmercury exposure.

  12. Volcanic tremors: Good indicators of change in plumbing systems during volcanic eruptions

    Science.gov (United States)

    Tárraga, Marta; Martí, Joan; Abella, Rafael; Carniel, Roberto; López, Carmen

    2014-03-01

    Geophysical and geochemical signals recorded during episodes of unrest preceding volcanic eruptions provide information on movements of magma inside the lithosphere and on how magma prepares to reach the surface. When the eruption ensues continuous volcanic monitoring can reveal the nature of changes occurring in the volcano's plumbing system, which may be correlated with changes in both eruption behaviour and products. During the 2011-2012 submarine eruption of El Hierro (Canary Islands), the seismic signal, surface deformation, a broad stain on the sea surface of the eruption site, and the occasional appearance of floating lava balloons and pyroclastic fragments were the main observable signs. A strong continuous tremor in the vent accompanied the eruption and varied significantly in amplitude, frequency and dynamical parameters. We analysed these variations and correlated them with changes in the distribution of earthquakes and in the petrology of the erupting magma. This enabled us to relate variations in tremors to changes in the (i) stress conditions of the plumbing system, (ii) dimensions of the conduit and vent, (iii) intensity of the explosive episodes, and (iv) rheological changes in the erupting magma. The results obtained show how the tremor signal was strongly influenced by stress changes in the host rock and in the rheological variations in the erupting magma. We conclude that the tracking of real-time syn-eruptive tremor signals via the observation of variations in plumbing systems and magma physics is a potentially effective tool for interpreting eruption dynamics, and suggest that similar variations observed in pre-eruptive tremors will have a similar origin.

  13. Defining the Treatment Gap: What Essential Tremor Patients Want That They Are Not Getting.

    Science.gov (United States)

    Louis, Elan D; Rohl, Brittany; Rice, Catherine

    2015-01-01

    Patient-centeredness (i.e., providing care that is responsive to individual patient preferences) is increasingly recognized as a crucial element of quality of care. A six-item patient-centeredness questionnaire was devised to assess the self-perceived needs of essential tremor (ET) patients. A link to the questionnaire was included in the monthly e-newsletter of the International Essential Tremor Foundation. The questionnaires were completed online and data were available in electronic format. There were 1,418 respondents. One in three respondents (i.e., 31.4%) indicated that the doctor was not even "moderately well-educated" about ET. Only 11.8% of respondents were satisfied with their care. Respondents raised a multiplicity of issues that were not being addressed in their current care. The top items were psychological services and support (33.9%), physical or occupational therapy (28.6%), handling embarrassment and social effects of tremor (15.8%), feelings of not being in control (13.7%), a detailed report and a more quantitative way of assessing tremor and tracking progression (12.7%), better counseling about current treatment and medications (11.9%), empathy, compassion and a feeling of being heard (11.6%), a treatment approach other than just medications and surgery (11.2%), and a discussion of all symptoms aside from tremor (e.g., cognition, balance). Patients with ET identified a broad range of issues that they felt were not addressed in their treatment; indeed, only one in 10 patients reported that they were satisfied with their care. It is hoped that patient-centered approaches such as this will lead to improved models for the care of patients with this common chronic disease.

  14. A Case of Action-Induced Clonus that Mimicked Action Tremors and was Associated with Cervical Schwannoma

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    Young-Hee Sung

    2010-10-01

    Full Text Available Clonus is the rhythmic muscle contraction which usually occurs in patients with lesions involving descending motor pathways. Sometimes, rhythmic oscillation of action induced clonus could be confused to action tremor. We report a case of action induced clonus associated with cervical schwannoma which was misdiagnosed as essential tremor. The patient had spasticity in all limbs with exaggerated tendon reflexes, and passive stretch-induced clonus. Imaging and histological examinations revealed a schwannoma extending from C2 to C7. The lesion was partially removed by surgery. Even though essential tremor is a common disease, clinician have to do sufficient neurologic examination considering differential diagnosis.

  15. The use of botulinum toxin in head and face medicine: An interdisciplinary field

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    Laskawi Rainer

    2008-03-01

    Full Text Available Abstract Background In this review article different interdisciplinary relevant applications of botulinum toxin type A (BTA in the head and face region are demonstrated. Patients with head and face disorders of different etiology often suffer from disorders concerning their musculature (example: synkinesis in mimic muscles or gland-secretion. This leads to many problems and reduces their quality of life. The application of BTA can improve movement disorders like blepharospasm, hemifacial spasm, synkinesis following defective healing of the facial nerve, palatal tremor, severe bruxism, oromandibular dystonias hypertrophy of the masseter muscle and disorders of the autonomous nerve system like hypersalivation, hyperlacrimation, pathological sweating and intrinsic rhinitis. Conclusion The application of botulinum toxin type A is a helpful and minimally invasive treatment option to improve the quality of life in patients with head and face disorders of different quality and etiology. Side effects are rare.

  16. 震颤的诊断和鉴别诊断策略%Differential diagnosis of tremor and its strategy

    Institute of Scientific and Technical Information of China (English)

    张文波; 王宇卉

    2012-01-01

    Tremors are the most prevalent movement disorder in clinic. Tremors can be classified on the basis of observable clinical characteristics: anatomical pattern, frequency amplitude and the related prominence of the tremor. Its diagnosis is still besed on clinical observation and descriptive analysis. This review describes the clinical features and investigational techniques for diagnosis of tremors.%震颤是最常见的运动障碍,临床上可根据震颤特征即发作方式、频率与幅度等进行分类.其诊断目前仍以临床观察与描述性分析为主.本文综述震颤的临床特征,常见及罕见原因,以及诊断分析过程.

  17. Tectonic tremor and slow slip along the northwestern section of the Mexico subduction zone

    Science.gov (United States)

    Brudzinski, Michael R.; Schlanser, Kristen M.; Kelly, Nicholas J.; DeMets, Charles; Grand, Stephen P.; Márquez-Azúa, Bertha; Cabral-Cano, Enrique

    2016-11-01

    The southwestern coast of Mexico is marked by active subduction of the Rivera and Cocos plates, producing megathrust earthquakes that tend to recur every 50-100 yr. Herein, we use seismic and GPS data from this region to investigate the potential relationship between earthquakes, tectonic (non-volcanic) tremor, and transient slip along the westernmost 200 km of the Mexico subduction zone. Visual examination of seismograms and spectrograms throughout the 18-month-long MARS seismic experiment reveals clear evidence for frequent small episodes of tremor along the Rivera and Cocos subduction zones beneath the states of Jalisco, Colima, and Michoacán. Using a semi-automated process that identifies prominent energy bursts in envelope waveforms of this new data, analyst-refined relative arrival times are inverted for source locations using a 1-D velocity model. The resulting northwest-southeast trending linear band of tremor is located downdip from the rupture zones of the 1995 Mw 8.0 Colima-Jalisco and 2003 Mw 7.2 Tecoman subduction-thrust earthquakes and just below the regions of afterslip triggered by these earthquakes. Despite the close proximity between tremor and megathrust events, there is no evidence that the time since the last great earthquake influences the spatial or temporal pattern of tremor. A well-defined gap in the tremor beneath the western Colima Graben appears to mark a separation along the subducted Rivera-Cocos plate boundary. From the position time series of 19 continuous GPS sites in western Mexico, we present the first evidence that slow slip events occur on the Rivera plate subduction interface. Unlike the widely-recorded, large-amplitude, slow slip events on the nearly horizontal Cocos plate subduction interface below southern Mexico, slow slip events below western Mexico have small amplitudes and are recorded at relatively few, mostly coastal stations. The smaller slow slip beneath western Mexico may be due to the steeper dip, causing a

  18. Repeatability of high-speed migration of tremor along the Nankai subduction zone, Japan

    Science.gov (United States)

    Kato, A.; Tsuruoka, H.; Nakagawa, S.; Hirata, N.

    2015-12-01

    Tectonic tremors have been considered to be a swarm or superimposed pulses of low-frequency earthquakes (LFEs). To systematically analyze the high-speed migration of tremor [e.g., Shelly et al., 2007], we here focus on an intensive cluster hosting many low-frequency earthquakes located at the western part of Shikoku Island. We relocated ~770 hypocenters of LFEs identified by the JMA, which took place from Jan. 2008 to Dec. 2013, applying double differential relocation algorithm [e.g., Waldhauser and Ellsworth, 2000] to arrival times picked by the JMA and those obtained by waveform cross correlation measurements. The epicentral distributions show a clear alignment parallel to the subduction of the Philippine Sea plate, as like a slip-parallel streaking. Then, we applied a matched-filter technique to continuous seismograms recorded near the source region using relocated template LFEs during 6 years (between Jan. 2008 and Dec. 2013). We newly detected about 60 times the number of template events, which is fairly larger than ones obtained by conventional envelope cross correlation method. Interestingly, we identified many repeated sequences of tremor migrations along the slip-parallel streaking (~350 sequences). Front of each or stacked migration of tremors can be modeled by a parabolic envelope, indicating a diffusion process. The diffusivity of parabolic envelope is estimated to be around 105 m2/s, which is categorized as high-speed migration feature (~100 km/hour). Most of the rapid migrations took place during occurrences of short-term slow slip events (SSEs), and seems to be triggered by ocean and solid Earth tides. The most plausible explanation of the high-speed propagation is a diffusion process of stress pulse concentrated within a cluster of strong brittle patches on the ductile shear zone [Ando et al., 2012]. The viscosity of the ductile shear zone within the streaking is at least one order magnitude smaller than that of the slow-speed migration. This

  19. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, more ... the body being studied. top of page How is the procedure performed? The technologist begins by positioning ...

  20. TremorScope: A Tool to Image the Deep Workings of the San Andreas Fault near Cholame, CA

    Science.gov (United States)

    Hellweg, M.; Burgmann, R.; Taira, T.; Nadeau, R. M.; Dreger, D. S.; Allen, R. M.

    2015-12-01

    Until recently, active fault zones were thought to deform via seismic slip during earthquakes in the upper, brittle portion of the crust, and by steady, aseismic shear below. However, since 2000, this view has been shaken by seismological observations of seismic tremor deep in the roots of active fault zones, including on the section of the San Andreas to the southeast of Parkfield, CA, deep (~20-30 km) beneath the nucleation zone of the great 1857 Fort Tejon earthquake. With funding from the Gordon and Betty Moore Foundation, we have improved the seismic network in the area above the tremor source by installing four new broadband/strong motion surface stations and four borehole sites with uphole accelerometers and downhole geophones, broadband and strong motion sensors. Data from all stations are telemetered in real-time. They are analysed as part of normal earthquake monitoring, and archived and distributed through the Northern California Earthquake Data Center (NCEDC). Data from the TremorScope project is improving earthquake monitoring in the region south of Parkfield, including allowing empirical Greens function finite fault analysis of moderate events in the area. Locations and characterization of tremor episodes are improved by the data recorded by TremorScope stations. For example, the rate of ambient tremor activity in the TremorScope area increased by a factor of ~8 within ~12 hours of the 2014 Napa M6.0 earthquake and remained elevated for ~ 100 days, exceeding the tremor rate increase following the 2004 Parkfield M6.0 quake despite the differences in epicentral distance (~300 km vs. ~15 km). No comparable increases in tremor rates have been observed between the Parkfield and Napa events. This suggests that the sensitivity to external stressing in the in the deep tremor zone of the TremorScope region may have increased since 2004. We also show how this network's strong motion instrumentation will provide unprecedented and exciting insights into the

  1. The fragile x-associated tremor and ataxia syndrome (FXTAS A síndrome de tremor e ataxia associada ao X frágil (FXTAS

    Directory of Open Access Journals (Sweden)

    Leonardo Pires Capelli

    2010-10-01

    Full Text Available FXTAS (Fragile X-associated tremor and ataxia syndrome is a late- onset neurodegenerative disorder affecting mainly men, over 50 years of age, who are carriers of the FMR1 gene premutation. The full mutation of this gene causes the fragile X syndrome (FXS, the most common cause of inherited mental retardation. Individuals affected by FXTAS generally present intention tremor and gait ataxia that might be associated to specific radiological and/or neuropathological signs. Other features commonly observed are parkinsonism, cognitive decline, peripheral neuropathy and autonomic dysfunction. Nearly a decade after its clinical characterization, FXTAS is poorly recognized in Brazil. Here we present a review of the current knowledge on the clinical, genetic and diagnostic aspects of the disease.A FXTAS (síndrome de tremor e ataxia associada ao X frágil é uma doença neurodegenerativa de início tardio que afeta principalmente homens acima dos 50 anos de idade, portadores de pré-mutação do gene FMR1. A mutação completa desse gene é responsável pela síndrome do cromossomo X frágil (SXF, a causa mais comum de deficiência mental herdada. Indivíduos afetados pela FXTAS geralmente apresentam tremor de intenção e ataxia de marcha que podem estar associados a sinais radiológicos ou neuropatológicos específicos. Outras características comumente observadas são parkinsonismo, declínio cognitivo, neuropatia periférica e disfunções autonômicas. Quase uma década após sua caracterização clínica, a FXTAS é mal conhecida por médicos no Brasil. Esta revisão apresenta o conhecimento atual sobre os aspectos clínicos, genéticos e diagnósticos da síndrome.

  2. Estimulação cerebral contínua (DBS talâmica para controle do tremor Deep brain stimulation of VIM thalamic nucleus for tremor control

    Directory of Open Access Journals (Sweden)

    José Augusto Nasser

    2002-06-01

    Full Text Available OBJETIVO: Apresentamos resultados da estimulação contínua do núcleo ventral intermédio (VIM talâmico para o controle do tremor. MÉTODO: Quatro pacientes foram selecionados no período de outubro de 1999 a janeiro de 2001 com tremor incapacitante refratário à farmacoterapia. Dois pacientes apresentavam tremor essencial (TE bilateral e 2 pacientes tremor de repouso por doença de Parkinson (DP, um à direita e outro à esquerda. Após avaliação sistemática, foram submetidos ao implante de eletrodo talâmico, modelo DBS 3387(Medtronic, para estimulação cerebral profunda (ECP com alta frequência, sendo este bilateral nos casos de TE e unilateral nos casos com tremor por DP. RESULTADOS: Os pacientes tiveram seu seguimente clínico até o presente, com média de 12 meses, sendo observada a eficácia da estimulação do núcleo VIM no controle dos disparos das células do tremor. As complicações temporárias do tipo parestesias, disartrias e discreto aumento do tônus foram revertidas após o ajuste dos parâmetros de estimulação. CONCLUSÃO: Os resultados confirmam os achados da literatura, de que a estimulação talâmica é excelente opção terapêutica no tratamento do tremor, havendo possibilidade de estimulação talâmica bilateral simultânea com segurança.PURPOSE: We present our results in 4 patients with tremor, in whom electrodes (uni and bilateral for Deep Brain Stimulation (DBS were implanted in the ventral intermediate nucleus (VIM of the thalamus. METHOD: Four patients with disabling tremor, with drug-resistant spite of optimum therapeutic trials with poor response were referred to do surgery. Two patients had bilateral essential tremor. These patients were implanted with electrodes for DBS 3387 (Medtronic. Two patients had unilateral parkinsonian tremor and they received unilateral implantation of model 3387 DBS. RESULTS: All four patients showed relieve of the tremor symptoms with significant tremor control seen at

  3. Study on the applicability of frequency spectrum of micro-tremor and dynamic characteristics of surface ground in Asia area

    Institute of Scientific and Technical Information of China (English)

    CHE Ai-lan; IWATATE Takahiro; ODA Yoshiya; GE Xiu-run

    2006-01-01

    The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan),Xi'an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were observed and analyzed by fast Fourier transform method (FFT). The response of ground soil to frequency of ground micro-tremor is revealed, and functions with frequency-dependence and frequency-selection of micro-tremor for different foundation soil strata are also researched.The horizontal to vertical spectral ratio (H/V, Nakamura technique) of micro-tremor observed at the surface ground was used to evaluate the site's predominant period. This paper also discusses the application of micro-tremor on site safety evaluation, and gives the observed calculation results obtained at multiple points. The experimental foundation and the deduction process of the method are described in detail. Some problems of the method are pointed out. Potential use of the technique's good expandable nature makes it a useable means for preventing and reducing disaster's harmful effects.

  4. Parkinson's disease without tremor masquerading as mechanical back pain; a case report.

    Science.gov (United States)

    Burton, Robert R

    2008-08-01

    The clinical features of a 67-year-old female suffering recurrent low back pain (LBP) who developed Parkinson's disease (PD) are presented. PD is a progressive, age-specific neuro-degenerative disorder characterized by a combination of bradykinesia (slowness of movement), rest tremor (initially unilaterally and usually of the hands), rigidity or stiffness of the arms, legs or neck, and/or postural instability. Other non-motor and cognitive symptoms may accompany these features. Tremor, at rest, is usually the earliest and most prominent cardinal symptom of PD, but is absent in approximately 30% of patients. Considering mechanical back pain commonly presents with slowed movement and gait disturbance due to pain avoidance behavior, and considering Canada's population is aging and living longer will inevitably cause the number of Parkinson's patients to increase, it is important for chiropractic doctors to maintain an awareness of the condition to facilitate its early referral, diagnosis and management.

  5. Observations of rapid-fire event tremor at Lascar volcano, Chile

    Directory of Open Access Journals (Sweden)

    H. Rademacher

    1996-06-01

    Full Text Available During the Proyecto de Investigaciòn Sismològica de la Cordillera Occidental (PISCO '94 in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, «rapid-fire» series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

  6. Observations of rapid-fire event tremor at Lascar volcano, Chile

    Science.gov (United States)

    Asch, Guenter; Wylegalla, K.; Hellweg, M.; Seidl, D.; Rademacher, H.

    1996-01-01

    During the Proyecto de Investigacio??n Sismolo??gica de la Cordillera Occidental (PISCO '94) in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, ??rapid-fire?? series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

  7. Pure Progressive Ataxia and Palatal Tremor (PAPT) Associated with a New Polymerase Gamma (POLG) Mutation.

    Science.gov (United States)

    Nicastro, Nicolas; Ranza, Emmanuelle; Antonarakis, Stylianos E; Horvath, Judit

    2016-12-01

    Progressive ataxia with palatal tremor (PAPT) is a syndrome caused by cerebellar and brainstem lesions involving the dentato-rubro-olivary tract and associated with hypertrophic olivary degeneration. Etiologies include acquired posterior fossa lesions (e.g. tumors, superficial siderosis, and inflammatory diseases) and genetic disorders, such as glial fibrillary acidic protein (GFAP) and polymerase gamma (POLG) mutations. We describe the case of a 52-year-old man who developed pure progressive ataxia and palatal tremor. Genetic analysis has shown that he is compound heterozygote for a known pathogenic (W748S) and a novel POLG variant (I1185N). Patients with POLG recessive mutations usually manifest a more complex clinical picture, including polyneuropathy and epilepsy; our case emphasizes the need to consider a genetic origin in a seemingly sporadic and pure PAPT.

  8. Is localised dehydration and vein generation the tremor-generating mechanism in subduction zones?

    Science.gov (United States)

    Fagereng, Ake; Meneghini, Francesca; Diener, Johann; Harris, Chris

    2017-04-01

    The phenomena of tectonic, non-volcanic, tremor was first discovered at the down-dip end of the seismogenic zone in Japan early this millennium. Now this low amplitude, low frequency, noise-like seismic signal has been observed at and/or below the deep limit of interseismic coupling along most well-instrumented subduction thrust interfaces. Data and models from these examples suggest a link between tremor and areas of elevated fluid pressure, or at least fluid presence. Tremor locations appear to also correlate with margin-specific locations of metamorphic fluid release, determined by composition and thermal structure. We therefore hypothesise that: (i) tremor on the deep subduction thrust interface is related to localised fluid release; and (ii) accretionary complex rocks exhumed from appropriate pressure - temperature conditions should include a record of this process, and allow a test for the hypothesis. Hydrothermal veins are a record of mineral precipitation at non-equilibrium conditions, commonly caused by fracture, fluid influx, and precipitation of dissolved minerals from this fluid. Quartz veins are ubiquitous in several accretionary complexes, including the Chrystalls Beach Complex, New Zealand, and the Kuiseb Schist of the Namibian Damara Belt. In both locations, representing temperatures of deformation of < 300 and < 600 °C respectively, there are networks of foliation-parallel and oblique veins, which developed incrementally and record a combination of shear and dilation. Required to have formed at differential stresses less than four times the tensile strength, and at fluid pressures exceeding the least compressive stress, these veins are consistent with tremorgenic conditions of low effective stress and mixed-mode deformation kinematically in agreement with shear on the plate interface. We have analysed the oxygen isotope composition of syntectonic quartz veins in both Chrystalls Beach Complex and Kuiseb Schist accretionary complexes, to unravel the

  9. Is essential tremor a Purkinjopathy? The role of the cerebellar cortex in its pathogenesis.

    Science.gov (United States)

    Grimaldi, Giuliana; Manto, Mario

    2013-11-01

    Essential tremor (ET) encompasses a group of progressive neurological diseases in which the primary clinical feature is kinetic tremor of the arms. There is accumulating evidence to suggest that the cerebellum is involved in the pathogenesis of ET; the clinical presentation, neurophysiological data, and functional and metabolic abnormalities revealed by neuroimaging studies all point toward the dysregulation of cerebellar circuits. Recent neuropathological findings at postmortem demonstrate that Purkinje neurons, and some brainstem neurons, play an integral role in the pathogenesis of this common neurological disorder. The assessment of Purkinje cell linear density shows that Purkinje density is abnormal in ET brains. Specific efforts need be devoted to understanding the molecular and cellular events occurring in the Purkinje neurons of the cerebellar cortex, which are emerging as being of particular importance in the pathogenesis of ET in a subgroup of patients. © 2013 International Parkinson and Movement Disorder Society.

  10. The Role of β-Carboline Alkaloids in the Pathogenesis of Essential Tremor.

    Science.gov (United States)

    Laviță, Svetlana Iuliana; Aro, Rania; Kiss, Béla; Manto, Mario; Duez, Pierre

    2016-06-01

    Essential tremor (ET) is one of the most prevalent neurological disorders in the world. Environmental factors have been implicated in the pathogenesis of ET. In particular, epidemiological studies have suggested that neurotoxic agents, especially β-carboline alkaloids (βCAs), might be generated through Maillard-type reaction. βCAs are molecules which are members of a large group of heterocyclic amines (HCAs, the so-called products of cooking meat). βCAs are highly tremorogenic in animals, producing a marked generalized action tremor soon after systemic administration in a wide range of laboratory animals such as mice, rats and monkeys. Administration of βCAs remains currently the main experimental model of ET. We review the pathogenesis of ET, with a focus on the biochemistry of βCAs, their occurrence and biological activity, their endogenous biosynthesis, their formation in food, their toxicokinetics and their neurotoxicity. We highlight open questions regarding the effects of βCAs in humans.

  11. Research Development and Perspective on Slow Slip, Tremors, and Slow Earthquakes

    Institute of Scientific and Technical Information of China (English)

    Wang Yanzhao; Shen Zhengkang

    2007-01-01

    Seismological and geodetic observations indicate that slow slip sometimes occurs in active fault zones beneath the seismogenic depth, and large slow slip can result in transient ground motion.Slow earthquakes, on the other hand, emit tremor-like signals within a narrow frequency band, and usually produce no catastrophic consequences. In general, slow slip and slow earthquakes probably correspond to deformation processes associated with releasing elastic energy in fault zones, and understanding their mechanisms may help improve our understanding of fault zone dynamic processes. This article reviews the research progress on slow slip and slow earthquakes over the last decade. Crustal motion and tremor activities associated with slow slip and slow earthquakes have been investigated extensively, mainly involving locating sources of slow slip and slow earthquakes and numerical modeling of their processes. In the meantime, debates have continued about slow slip and slow earthquakes,such as their origins, relationship, and mechanisms.

  12. Geodetic and seismic signatures of episodic tremor and slip in the northern Cascadia subduction zone

    Science.gov (United States)

    Dragert, H.; Wang, K.; Rogers, G.

    2004-12-01

    Slip events with an average duration of about 10 days and effective total slip displacements of severalc entimetres have been detected on the deeper (25 to 45 km) part of the northern Cascadia subduction zone interface by observing transient surface deformation on a network of continuously recording Global Positioning System (GPS) sites. The slip events occur down-dip from the currently locked, seismogenic portion of the subduction zone, and, for the geographic region around Victoria, British Columbia, repeat at 13 to 16 month intervals. These episodes of slip are accompanied by distinct, low-frequency tremors, similar to those reported in the forearc region of southern Japan. Although the processes which generate this phenomenon of episodic tremor and slip (ETS) are not well understood, it is possible that the ETS zone may constrain the landward extent of megathrust rupture, and conceivable that an ETS event could precede the next great thrust earthquake.

  13. Strength stimuli on the quadriceps femoris influences the physiological tremor of the index finger

    CERN Document Server

    Lainez, Miguel J A; Gallach, Jose E; Moras, Gerard; Ranz, Daniel; Toca-Herrera, Jose L

    2008-01-01

    The influence of fatiguing stimuli applied to the quadriceps femoris on the tremor of the index finger on sixteen healthy subjects has been investigated, by measuring the acceleration and the electromyography activity of the extensor digitorum at two different speeds. No significant changes in the basal condition could be measured at 0.52 rad/s. However, at 1.05 rad/s the tremor amplitude (12.23%, p<0.05) and the electromyography activity (20.19%, p<0.05) increased in the time domain. In the frequential domain, the peak associated to the acceleration increased in 26.30% (p<0.05), while the electromiography activity experienced an increase of 81.34% (p<0.05). The largest change in frequency took place in the range 7-17 Hz. The discussion of the results leads to the conclusion that the supraespinal mechanism is responsible for the measured effect.

  14. Dysregulated iron metabolism in the choroid plexus in fragile X-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Ariza, Jeanelle; Steward, Craig; Rueckert, Flora; Widdison, Matt; Coffman, Robert; Afjei, Atiyeh; Noctor, Stephen C; Hagerman, Randi; Hagerman, Paul; Martínez-Cerdeño, Verónica

    2015-02-19

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with premutation alleles of the FMR1 gene that is characterized by progressive action tremor, gait ataxia, and cognitive decline. Recent studies of mitochondrial dysfunction in FXTAS have suggested that iron dysregulation may be one component of disease pathogenesis. We tested the hypothesis that iron dysregulation is part of the pathogenic process in FXTAS. We analyzed postmortem choroid plexus from FXTAS and control subjects, and found that in FXTAS iron accumulated in the stroma, transferrin levels were decreased in the epithelial cells, and transferrin receptor 1 distribution was shifted from the basolateral membrane (control) to a predominantly intracellular location (FXTAS). In addition, ferroportin and ceruloplasmin were markedly decreased within the epithelial cells. These alterations have implications not only for understanding the pathophysiology of FXTAS, but also for the development of new clinical treatments that may incorporate selective iron chelation.

  15. Dynamic biomechanics of the human head in lateral impacts

    OpenAIRE

    Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A.

    2009-01-01

    The biomechanical responses of human head (translational head CG accelerations, rotational head accelerations, and HIC) under lateral impact to the parietal-temporal region were investigated in the current study. Free drop tests were conducted at impact velocities ranging from 2.44 to 7.70 m/s with a 40 durometer, a 90 durometer flat padding, and a 90 durometer cylinder. Specimens were isolated from PMHS subjects at the level of occipital condyles, and the intracranial substance was replaced ...

  16. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Bartosch, T. [Erlanger-Nuernberg Univ., Erlanger (Germany). Lehrstul fuer Nachrichtentechnik I; Seidl, D. [Seismologisches Zentralobservatorium Graefenberg, Erlanegen (Greece). Bundesanstalt fuer Geiwissenschaften und Rohstoffe

    1999-06-01

    Among a variety of spectrogram methods short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were selected to analyse transients in non-stationary signals. Depending on the properties of the tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli (Italy).

  17. The assessment of neural injury following open heart surgery by physiological tremor analysis.

    Science.gov (United States)

    Németh, Adám; Hejjel, László; Ajtay, Zénó; Kellényi, Lóránd; Solymos, Andor; Bártfai, Imre; Kovács, Norbert; Lenkey, Zsófia; Cziráki, Attila; Szabados, Sándor

    2013-02-21

    The appearance of post-operative cognitive dysfunction as a result of open heart surgery has been proven by several studies. Focal and/or sporadic neuron damage emerging in the central nervous system may not only appear as cognitive dysfunction, but might strongly influence features of physiological tremor. We investigated 110 patients (age: 34-73 years; 76 male, 34 female; 51 coronary artery bypass grafting (CABG), 25 valve replacement, 25 combined open heart surgery, 9 off-pump CABG) before surgery and after open-heart surgery on the 3(rd) to 5(th) post-operative day. The assessment of the physiological tremor analysis was performed with our newly developed equipment based on the Analog Devices ADXL 320 JPC integrated accelerometer chip. Recordings were stored on a PC and spectral analysis was performed by fast Fourier transformation (FFT). We compared power integrals in the 1-4 Hz, 4-8 Hz and 8-12 Hz frequency ranges and these were statistically assessed by the Wilcoxon rank correlation test. We found significant changes in the power spectrum of physiological tremor. The spectrum in the 8-12 Hz range (neuronal oscillation) decreased and a shift was recognised to the lower spectrum (p < 0.01). The magnitude of the shift was not significantly higher for females than for males (p < 0.157). We found no significant difference between the shift and the cross-clamp or perfusion time (p < 0.6450). The assessment of physiological tremor by means of our novel, feasible method may provide a deeper insight into the mechanism of central nervous system damage associated with open heart surgery.

  18. Standardized Handwriting to Assess Bradykinesia, Micrographia and Tremor in Parkinson's Disease

    Science.gov (United States)

    Smits, Esther J.; Tolonen, Antti J.; Cluitmans, Luc; van Gils, Mark; Conway, Bernard A.; Zietsma, Rutger C.; Leenders, Klaus L.; Maurits, Natasha M.

    2014-01-01

    Objective To assess whether standardized handwriting can provide quantitative measures to distinguish patients diagnosed with Parkinson's disease from age- and gender-matched healthy control participants. Design Exploratory study. Pen tip trajectories were recorded during circle, spiral and line drawing and repeated character ‘elelelel’ and sentence writing, performed by Parkinson patients and healthy control participants. Parkinson patients were tested after overnight withdrawal of anti-Parkinsonian medication. Setting University Medical Center Groningen, tertiary care, the Netherlands. Participants Patients with Parkinson's disease (n = 10; mean age 69.0 years; 6 male) and healthy controls (n = 10; mean age 68.1 years; 6 male). Interventions Not applicable. Main Outcome Measures Movement time and velocity to detect bradykinesia and the size of writing to detect micrographia. A rest recording to investigate the presence of a rest-tremor, by frequency analysis. Results Mean disease duration in the Parkinson group was 4.4 years and the patients were in modified Hoehn-Yahr stages 1–2.5. In general, Parkinson patients were slower than healthy control participants. Median time per repetition, median velocity and median acceleration of the sentence task and median velocity of the elel task differed significantly between Parkinson patients and healthy control participants (all p<0.0014). Parkinson patients also wrote smaller than healthy control participants and the width of the ‘e’ in the elel task was significantly smaller in Parkinson patients compared to healthy control participants (p<0.0014). A rest-tremor was detected in the three patients who were clinically assessed as having rest-tremor. Conclusions This study shows that standardized handwriting can provide objective measures for bradykinesia, tremor and micrographia to distinguish Parkinson patients from healthy control participants. PMID:24854199

  19. Standardized handwriting to assess bradykinesia, micrographia and tremor in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Esther J Smits

    Full Text Available OBJECTIVE: To assess whether standardized handwriting can provide quantitative measures to distinguish patients diagnosed with Parkinson's disease from age- and gender-matched healthy control participants. DESIGN: Exploratory study. Pen tip trajectories were recorded during circle, spiral and line drawing and repeated character 'elelelel' and sentence writing, performed by Parkinson patients and healthy control participants. Parkinson patients were tested after overnight withdrawal of anti-Parkinsonian medication. SETTING: University Medical Center Groningen, tertiary care, the Netherlands. PARTICIPANTS: Patients with Parkinson's disease (n = 10; mean age 69.0 years; 6 male and healthy controls (n = 10; mean age 68.1 years; 6 male. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Movement time and velocity to detect bradykinesia and the size of writing to detect micrographia. A rest recording to investigate the presence of a rest-tremor, by frequency analysis. RESULTS: Mean disease duration in the Parkinson group was 4.4 years and the patients were in modified Hoehn-Yahr stages 1-2.5. In general, Parkinson patients were slower than healthy control participants. Median time per repetition, median velocity and median acceleration of the sentence task and median velocity of the elel task differed significantly between Parkinson patients and healthy control participants (all p<0.0014. Parkinson patients also wrote smaller than healthy control participants and the width of the 'e' in the elel task was significantly smaller in Parkinson patients compared to healthy control participants (p<0.0014. A rest-tremor was detected in the three patients who were clinically assessed as having rest-tremor. CONCLUSIONS: This study shows that standardized handwriting can provide objective measures for bradykinesia, tremor and micrographia to distinguish Parkinson patients from healthy control participants.

  20. Anomalous tremor before 2008 Ms8. 0 Wenchuan earthquake: a review

    Directory of Open Access Journals (Sweden)

    Hao Xiaoguang

    2011-08-01

    Full Text Available In this paper we give a review of several previously published papers on anomalous tremors observed before the 2008 Ms8. 0 Wenchuan earthquake. Based on the observed time and frequency shifts between coastal and inland stations, we discussed some methods to distinguish different kinds of microseisms, and speculated that a pre-earthquake typhoon might have caused a “mainland-originated microseism” which in turn triggered the earthquake.

  1. Lower levels of uric acid and striatal dopamine in non-tremor dominant Parkinson's disease subtype

    Science.gov (United States)

    Huertas, Ismael; Jesús, Silvia; Lojo, José Antonio; García-Gómez, Francisco Javier; Cáceres-Redondo, María Teresa; Oropesa-Ruiz, Juan Manuel; Carrillo, Fátima; Vargas-Gonzalez, Laura; Martín Rodríguez, Juan Francisco; Gómez-Garre, Pilar; García-Solís, David; Mir, Pablo

    2017-01-01

    Parkinson’s disease (PD) patients who present with tremor and maintain a predominance of tremor have a better prognosis. Similarly, PD patients with high levels of uric acid (UA), a natural neuroprotectant, have also a better disease course. Our aim was to investigate whether PD motor subtypes differ in their levels of UA, and if these differences correlate with the degree of dopamine transporter (DAT) availability. We included 75 PD patients from whom we collected information about their motor symptoms, DAT imaging and UA concentration levels. Based on the predominance of their motor symptoms, patients were classified into postural instability and gait disorder (PIGD, n = 36), intermediate (I, n = 22), and tremor-dominant (TD, n = 17) subtypes. The levels of UA and striatal DAT were compared across subtypes and the correlation between these two measures was also explored. We found that PIGD patients had lower levels of UA (3.7 vs 4.5 vs 5.3 mg/dL; P<0.001) and striatal DAT than patients with an intermediate or TD phenotype. Furthermore, UA levels significantly correlated with the levels of striatal DAT. We also observed that some PIGD (25%) and I (45%) patients had a predominance of tremor at disease onset. We speculate that UA might be involved in the maintenance of the less damaging TD phenotype and thus also in the conversion from TD to PIGD. Low levels of this natural antioxidant could lead to a major neuronal damage and therefore influence the conversion to a more severe motor phenotype. PMID:28358829

  2. The effects of physiological adjustments on the perceptual and acoustical characteristics of simulated laryngeal vocal tremor

    OpenAIRE

    Rosemary A Lester; Story, Brad H.

    2015-01-01

    The purpose of this study was to determine if adjustments to the voice source [i.e., fundamental frequency (F0), degree of vocal fold adduction] or vocal tract filter (i.e., vocal tract shape for vowels) reduce the perception of simulated laryngeal vocal tremor and to determine if listener perception could be explained by characteristics of the acoustical modulations. This research was carried out using a computational model of speech production that allowed for precise control and manipulati...

  3. Kernohan-Woltman notch phenomenon and intention tremors in case of chronic subdural hematoma

    Directory of Open Access Journals (Sweden)

    Sasikala P.

    2014-03-01

    Full Text Available Movement disorders are atypical and rare presentation of chronic subdural hematomas. We report a case of 60 year man who presented with intention tremors and altered sensorium. The patient had Kernohan-Woltman notch phenomenon on clinical examination. CT scan brain showed a large left fronto-temporo-parietal chronic subdural hematoma with significant mass effect and midline shift. His symptoms relieved completely after surgical evacuation of the hematoma.

  4. Acute chlordecone toxicity in rats: a relationship between tremor and ATPase activities.

    Science.gov (United States)

    Jordan, J E; Grice, T; Mishra, S K; Desaiah, D

    1981-10-01

    Since we have demonstrated that ATPase system was sensitive to chlordecone, it was decided to examine the relationship between physiological and biochemical responses to this neurotoxin. Male Sprague-Dawley rats were fed with chlordecone by gastric intubation at 10, 25 and 50 mg/kg/day for three days. Control rats received 0.3 ml of corn oil. Complete body movements (including tremors) were monitored for a period of 12 hr at 24, 48 and 72 hr after treatment by a piezoelectric crystal attached to the bottom of a plastic rodent cage. The output of the crystal was recorded by a Grass model of EEG machine and magnetic tape. For biochemical study chlordecone treated rats were killed, the brain synaptosomes were prepared and Na+-K+ ATPase, oligomycin-sensitive and insensitive Mg2+ ATPases were determined. Rats receiving chlordecone showed an increased tremor activity which was significant and dose- dependent with a correlation coefficient of the regression line of 0.96. The onset of tremors was evident as early as 2 hr in 50 mg/kg dosed rats. Behavioral abnormalities include startling response to external stimuli like sound, etc. The brain synaptosomal Na+-K+ and oligomycin-sensitive Mg2+ ATPases were significantly decreased in chlordecone treated rats as compared to controls and the decrease was dose-dependent. A linear relationship was observed between the decreases in ATPase activities and physiological (tremor) activity with an r value of 0.96. These results suggest that the inhibition of ATPase system in brain may be related to the production of the neurotoxic symptoms.

  5. Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.

    Directory of Open Access Journals (Sweden)

    Francesco Budini

    Full Text Available The present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature in patients affected by pathological tremors; understanding its mechanisms is therefore important. Thirteen healthy volunteers (23±4 years performed elbow flexor sustained contractions both against a spring load and in isometric conditions at 20% of maximal voluntary isometric contraction (MVC. Spring stiffness was selected to induce instability in the stretch reflex servo loop. 64 EEG channels, surface EMG from the biceps brachii muscle and force were simultaneously recorded. Contractions against the spring resulted in greater fluctuations of the force signal and EMG amplitude compared to isometric conditions (p<.05. During isometric contractions CMC was systematically found in the beta band and sporadically observed in the alpha band. However, during the contractions against the spring load, CMC in the alpha band was observed in 12 out of 13 volunteers. Partial directed coherence (PDC revealed an increased information flow in the EMG to EEG direction in the alpha band (p<.05. Therefore, coherence in the alpha band between the sensory-motor cortex and the biceps brachii muscle can be systematically induced in healthy individuals by mechanically amplifying tremor. The increased information flow in the EMG to EEG direction may reflect enhanced afferent activity from the muscle spindles. These results may contribute to the understanding of the presence of alpha band CMC in tremor related pathologies by suggesting that the origin of this phenomenon may not only be at cortical level but may also be affected by spinal circuit loops.

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses ... of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  7. A Quantitative Assessment of Tremor and Ataxia in Female FMR1 Premutation Carriers Using CATSYS

    Directory of Open Access Journals (Sweden)

    Vivien Narcisa

    2011-01-01

    Full Text Available The fragile X-associated tremor/ataxia syndrome (FXTAS is a relatively common cause of balance problems leading to gait disturbances in older males (40% with the premutation. FXTAS is less common in females. We utilized the CATSYS system, a quantitative measure of movement, in 23 women with FXTAS (mean age 62.7; SD 12.3, 90 women with the premutation without FXTAS (mean age 52.9; SD 9.4, and 37 controls (mean age 56.53; SD 7.8. CATSYS distinguished differences between carriers with and without FXTAS in postural tremor, postural sway, hand coordination, and reaction time tasks. Differences were also seen between carriers without FXTAS and controls in finger tapping, reaction time, and one postural sway task. However, these differences did not persist after statistical correction for multiple comparisons. Notably, there were no differences across groups in intention tremor. This is likely due to the milder symptoms in females compared to males with FXTAS.

  8. Predictive value of the smell identification test for nigrostriatal dopaminergic depletion in Korean tremor patients.

    Science.gov (United States)

    Hong, Jin Yong; Chung, Seok Jong; Lee, Ji E; Sunwoo, Mun Kyung; Lee, Phil Hyu; Sohn, Young H

    2013-11-01

    The predictive value of Cross-Cultural Smell Identification Test for nigrostriatal dopaminergic depletion in Korean tremor patients has yet to be assessed. Three hundred nineteen drug-naive patients who visited our clinic for the diagnosis of their tremor, and took both Cross-Cultural Smell Identification Test and dopamine transporter PET were included in the data analysis. Visual grading of each PET image was performed by two independent neurologists. Smell test scores were significantly correlated to the striatal dopaminergic activity (Kendall's τb = -0.291, p smell test score alone appeared to have relatively weak power for predicting dopaminergic depletion (area under the curve = 0.693). Multivariate logistic regression model with inclusion of the patient's age and symptom duration as independent variables enhanced predictive power for dopaminergic depletion (area under the curve = 0.812). These results demonstrated that Cross-Cultural Smell Identification Test measurements alone may be insufficient to predict striatal dopaminergic depletion in Korean tremor patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Tiny intraplate earthquakes triggered by nearby episodic tremor and slip in Cascadia

    Science.gov (United States)

    Vidale, J.E.; Hotovec, A.J.; Ghosh, A.; Creager, K.C.; Gomberg, J.

    2011-01-01

    Episodic tremor and slip (ETS) has been observed in many subduction zones, but its mechanical underpinnings as well as its potential for triggering damaging earthquakes have proven difficult to assess. Here we use a seismic array in Cascadia of unprecedented density to monitor seismicity around a moderate 16 day ETS episode. In the 4 months of data we examine, we observe five tiny earthquakes within the subducting slab during the episode and only one more in the same area, which was just before and nearby the next ETS burst. These earthquakes concentrate along the sides and updip edge of the ETS region, consistent with greater stress concentration there than near the middle and downdip edge of the tremor area. Most of the seismicity is below the megathrust, with a similar depth extent to the background intraslab seismicity. The pattern of earthquakes that we find suggests slow slip has a more continuous temporal and spatial pattern than the tremor loci, which notoriously appear in bursts, jumps, and streaks. Copyright 2011 by the American Geophysical Union.

  10. MRI Guided Focused Ultrasound Thalamotomy for Moderate-to-Severe Tremor in Parkinson’s Disease

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    Ilana Schlesinger

    2015-01-01

    Full Text Available Background. Thalamotomy is effective in alleviating tremor in Parkinson’s disease (PD. Methods. Seven PD patients, mean age 59.4 ± 9.8 years (range, 46–74 with a mean disease duration of 5.4 ± 2.8 years (range, 2–10 suffering from severe refractory tremor, underwent ventral intermediate nucleus thalamotomy using MRI guided focused ultrasound (MRgFUS, an innovative technology that enables noninvasive surgery. Results. Tremor stopped in the contralateral upper extremity in all patients immediately following treatment. Total UPDRS decreased from 37.4 ± 12.2 to 18.8 ± 11.1 (p=0.007 and PDQ-39 decreased from 42.3 ± 16.4 to 21.6 ± 10.8 (p=0.008 following MRgFUS. These effects were sustained (mean follow-up 7.3 months. Adverse events during MRgFUS included headache (n=3, dizziness (n=2, vertigo (n=4, and lip paresthesia (n=1 and following MRgFUS were hypogeusia (n=1, unsteady feeling when walking (n=1, resolved, and disturbance when walking tandem (n=1, resolved. Conclusions. Thalamotomy using MRgFUS is safe and effective in PD patients. Large randomized studies are needed to assess prolonged efficacy and safety.

  11. Linear stability of plane Poiseuille flow in an infinite elastic medium and volcanic tremors

    Science.gov (United States)

    Sakuraba, Ataru; Yamauchi, Hatsuki

    2014-12-01

    The linear stability of a plane compressible laminar (Poiseuille) flow sandwiched between two semi-infinite elastic media was investigated with the aim of explaining the excitation of volcanic tremors. Our results show that there are several regimes of instability, and the nature of stability significantly depends on the symmetry of oscillatory fluid and solid motion. It has been shown that long-wave symmetric instability occurs at a very small value of the Reynolds number, but it is unlikely that this is the cause of volcanic tremors. We show that antisymmetric (flexural) instability also occurs, involving two parallel Rayleigh waves traveling against the Poiseuille flow, but the critical flow speed is faster than that of symmetric instability. However, if the basic flow profile is nonparabolic because of a nonuniform driving force or nonuniform viscosity, the critical flow speed of antisymmetric instability can be considerably slower than that of symmetric instability. Based on numerical calculations and analytical consideration, we conclude that this anomalous antisymmetric instability is possibly produced by a basaltic magma flow of a few meters per second through a dike with thickness of 1 m and extending for several kilometers; this origin can explain some of the characteristics of volcanic tremors.

  12. Onset of Bronchodilation and Finger Tremor Induced by Salmeterol and Salbutamol in Asthmatic Patients

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    Jan Lötvall

    1998-01-01

    Full Text Available Salmeterol is a beta-agonist with bronchodilator properties that last for at least 12 h after inhalation. However, the onset of action of salmeterol immediately after inhalation has not been sufficiently investigated. In the present study, the onset of action and tremor-inducing effect of two doses of inhaled salmeterol (50 and 100 µg were compared with inhaled salbutamol (200 and 400 µg and placebo. Lung function was measured using forced expiratory volume in 1 s (FEV, and tremor was measured using a linear accelerometer. With salbutamol there was rapid bronchodilation, both doses producing more than 15% improvement in mean FEV1 within 2 mins of inhalation. With salmeterol, on the other hand, significant bronchodilation was delayed until 7 mins versus placebo, and the full bronchodilation effect was not achieved until 60 mins after inhalation. There was a much more rapid onset of tremor with salbutamol (400 µg than salmeterol. There was a much slower onset of bronchodilation with salmeterol than salbutamol. Therefore, salmeterol cannot be recommended to relieve acute symptoms.

  13. Automatic Assessing of Tremor Severity Using Nonlinear Dynamics, Artificial Neural Networks and Neuro-Fuzzy Classifier

    Directory of Open Access Journals (Sweden)

    GEMAN, O.

    2014-02-01

    Full Text Available Neurological diseases like Alzheimer, epilepsy, Parkinson's disease, multiple sclerosis and other dementias influence the lives of patients, their families and society. Parkinson's disease (PD is a neurodegenerative disease that occurs due to loss of dopamine, a neurotransmitter and slow destruction of neurons. Brain area affected by progressive destruction of neurons is responsible for controlling movements, and patients with PD reveal rigid and uncontrollable gestures, postural instability, small handwriting and tremor. Commercial activity-promoting gaming systems such as the Nintendo Wii and Xbox Kinect can be used as tools for tremor, gait or other biomedical signals acquisitions. They also can aid for rehabilitation in clinical settings. This paper emphasizes the use of intelligent optical sensors or accelerometers in biomedical signal acquisition, and of the specific nonlinear dynamics parameters or fuzzy logic in Parkinson's disease tremor analysis. Nowadays, there is no screening test for early detection of PD. So, we investigated a method to predict PD, based on the image processing of the handwriting belonging to a candidate of PD. For classification and discrimination between healthy people and PD people we used Artificial Neural Networks (Radial Basis Function - RBF and Multilayer Perceptron - MLP and an Adaptive Neuro-Fuzzy Classifier (ANFC. In general, the results may be expressed as a prognostic (risk degree to contact PD.

  14. Imaging coherent sources of tremor related EEG activity in patients with Parkinson's disease.

    Science.gov (United States)

    Muthuraman, M; Raethjen, J; Hellriegel, H; Deuschl, G; Heute, U

    2008-01-01

    The cortical sources of both the basic and first 'harmonic' frequency of Parkinsonian tremor are addressed in this paper. The power and coherence was estimated using the multitaper method for EEG and EMG data from 6 Parkinsonian patients with a classical rest tremor. The Dynamic Imaging of Coherent Sources (DICS) was used to find the coherent sources in the brain. Before hand this method was validated for the application to the EEG by showing in 3 normal subjects that rhythmic stimuli (1-5Hz) to the median nerve leads to almost identical coherent sources for the basic and first harmonic frequency in the contralateral sensorimotor cortex which is the biologically plausible result. In all the Parkinson patients the corticomuscular coherence was also present in the basic and the first harmonic frequency of the tremor. However, the source for the basic frequency was close to the frontal midline and the first harmonic frequency was in the region of premotor and sensory motor cortex on the contralateral side for all the patients. Thus the generation of these two oscillations involves different cortical areas and possibly follows different pathways to the periphery.

  15. Migration Episode of Shallow Low-frequency Tremor at the Nankai Trough Subduction Zone: Seismological Evidence for Episodic Slow Slip Event Occurring at the Shallow Transition Zone

    Science.gov (United States)

    Yamashita, Y.; Yakiwara, H.; Shimizu, H.; Uchida, K.; Hirano, S.; Miyamachi, H.; Umakoshi, K.; Nakamoto, M.; Fukui, M.; Kamizono, M.; Kanehara, H.; Yamada, T.; Shinohara, M.; Obara, K.

    2014-12-01

    To understand the shallow part of plate interface between megathrust seismogenic zone and trench axis is very important for development of huge earthquake rupture and generation of tsunami. Monitoring of offshore seismicity near the Nankai trough by temporal ocean bottom seismographic observation in 2013 revealed that low-frequency tremor occurred associated with shallow very-low-frequency earthquakes (VLFEs) in the shallow part of plate interface. The shallow tremor episode lasted for approximately 1 month, which is almost consistent with the shallow VLFE activity observed from land broad-band seismic stations [Asano, 2014]. The horizontal location of shallow tremor estimate by envelope correlation method [Obara, 2002] shows a belt-like distribution along trench strike with narrow width than the deep tremor. The most remarkable feature of the shallow tremor activity is migration. There are two migration modes including diffusive slower migration and rapid tremor reversal (RTR), which are very similar to the deep tremor as a part of the ETS. This strongly indicates a possibility of the occurrence of episodic slow slip event in the shallow transition zone. That is to say, the migration of shallow tremor is supposed to be caused by migrating rupture front of SSE. In addition, the migration was detouring around the subducted Kyushu-Palau ridge. This suggests that the occurrence of tremor is sensitive to change in the shape of plate interface and seeks to propagate along almost the same depth range, in other word, a specified temperature and pressure condition. The narrow width distribution of shallow tremor also indicates that the shallow tremor is strongly related to dehydration process of a specified mineral under a narrow limited range of temperature and pressure condition compared to the deep tremor.

  16. Noise Reduction for a MEMS-Gyroscope-Based Head Mouse.

    Science.gov (United States)

    Du, Jiaying; Gerdtman, Christer; Lindén, Maria

    2015-01-01

    In this paper, four different signal processing algorithms which can be applied to reduce the noise from a MEMS-gyroscope-based computer head mouse are presented. MEMS-gyroscopes are small, light, cheap and widely used in many electrical products. MultiPos, a MEMS-gyroscope-based computer head mouse system was designed for persons with movement disorders. Noise such as physiological tremor and electrical noise is a common problem for the MultiPos system. In this study four different signal processing algorithms were applied and evaluated by simulation in MATLAB and implementation in a dsPIC, with aim to minimize the noise in MultiPos. The algorithms were low-pass filter, Least Mean Square (LMS) algorithm, Kalman filter and Weighted Fourier Linear Combiner (WFLC) algorithm. Comparisons and system tests show that these signal processing algorithms can be used to improve the MultiPos system. The WFLC algorithm was found the best method for noise reduction in the application of a MEMS-gyroscope-based head mouse.

  17. Worse and Worse and Worse: Essential Tremor Patients’ Longitudinal Perspectives on their Condition

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    Jesus Gutierrez

    2016-10-01

    Full Text Available Background: Essential tremor (ET patients regularly inquire about their prognosis. Therefore, physicians have cause to review available medical literature for meaningful answers. Longitudinal studies are ideally suited to provide a glimpse into the evolution of tremor. Despite its high prevalence, there are surprisingly few longitudinal clinical studies of ET. Furthermore, none of them provided data from the patients’ perspective. Understanding the patient vantage point is valuable as it is the starting point of personalized medicine. Given the progressive nature of ET, we hypothesized that many patients will experience an increase in symptom severity over time. However, due to a lack of clinical data, the exact nature of this progression is unclear. For example, whether patients experience a worsening at each time interval is simply not known. In this longitudinal study, we assessed whether ET patients felt that their symptoms had worsened between each follow-up evaluation and try to identify specific clinical characteristics associated with this experience.Methods: A cohort of 164 ET cases enrolled in a prospective, longitudinal research study. After a baseline in-person assessment, they received regular telephone evaluations for up to 5.25 years, beginning in 2009. During each follow-up evaluation, cases answered the question, has your ET worsened since our last call? Results: Two-thirds (104 63.4% of ET cases reported worsening at one-half or more of their follow-up evaluations. Furthermore, one-in-four cases (44 26.8% reported worsening at every follow-up evaluation. Self-reported worsening was not associated with any of the baseline clinical variables assessed, including age, gender, tremor duration, age at tremor onset, or total tremor score. Conclusions: Little has been written from the patient perspective on progression of ET. When followed longitudinally at regular intervals, a majority of ET cases we studied reported worsening one

  18. A causal relationship between the slow slip event and deep low frequency tremor indicated by strain data recorded at Shingu borehole station

    Science.gov (United States)

    Fukuda, M.; Sagiya, T.; Asai, Y.

    2008-12-01

    In the southwest Japan, synchronized deep low frequency tremors and short-term slow slip events occur repeatedly in several regions such as Tokai, northern Kii Peninsula and western Shikoku areas, and these activities are partitioned by 'gaps' of tremors. Although concurrent occurrences of slow slips and tremors have been detected at various subducting plate boundary, their physical mechanism is still not well understood. We are monitoring crustal deformation at Shingu city on the southeastern coast of Kii Peninsula, with an integrated multi-component borehole monitoring system developed by Ishii et al. [2002]. The borehole sensor unit consists of 6 strain sensors (4 in horizontal, 2 in vertical), 2 pendulum tilt sensors, magnetic direction finder and a quartz thermometer and installed at 510m depth. Fukuda et al. [2007] reported two types of strain changes, one associated with deep low frequency tremors and the other without tremors from November 2005 to March 2006. We extend the analysis period to 41 months, from January 2004 to September 2007. We identified 11 episodic strain changes. One of them was caused by heavy rainfall but the rest of the changes are considered to be slow slips. Among all the slow slips identified, five events occurred associated with reported tremor events, but the rest 5 changes were not accompanied by tremors. These slow slip events are characterized by N-S compression (0.017 - 0.063 ppm), and E-W extension (0.013 - 0.071 ppm), NW-SE extension (0.008 - 0.097 ppm), and last 4 - 9 days. We estimate a fault model for each event by forward modeling, and find that the all the strain changes can be attributed to reverse faulting on the plate boundary beneath the Kii Peninsula. An interesting strain change occurred from 26 Dec. 2004 to 2 Jan. 2005. In this period, a tremor activity propagated southwestward on central Kii Peninsula and the level of activity remarkably drops when the activity propagated into the tremor gap zone. After that, the

  19. Isolated lingual involvement in Wilson's disease.

    Science.gov (United States)

    Choudhary, Neera; Joshi, Laxmikant; Duggal, Ashish; Puri, Vinod; Khwaja, Geeta Anjum

    2015-01-01

    Lingual involvement can occur in a variety of neurological disorders including pyramidal, extrapyramidal and lower motor neuron disorders. It can be seen in the form of tremor, bradykinesia, dystonia, atrophy and weakness of tongue movements and can clinically present as difficulty in swallowing and dysarthria which can be a source of great discomfort to the patient. We describe a patient who presented with isolated lingual involvement and was diagnosed to have Wilsons's disease. This case emphasizes the clinical variability in presentation of Wilson's disease and importance of early clinical diagnosis.

  20. Seismic tremor and gravity measurements at Inferno Crater Lake, Waimangu Geothermal Field, New Zealand

    Science.gov (United States)

    O'Brien, J. F.; Jolly, A. D.; Fournier, N.; Cole-Baker, J.; Hurst, T.; Roman, D. C.

    2011-12-01

    Volcanic crater lakes are often associated with active hydrothermal systems that induce cyclic behavior in the lake's level, temperature, and chemistry. Inferno Crater Lake, located in the Waimangu geothermal field within the Taupo Volcanic Zone (TVZ) on the North Island of New Zealand exhibits lake level fluctuations of >7m, and temperature fluctuations >40°C with a highly variable periodicity. Seismic and gravity monitoring of Inferno Lake was carried out from December, 2009 - March, 2010 and captured a full cycle of lake fluctuation. Results indicate that this cycle consisted of ~5 smaller fluctuations of ~3m in lake level followed by a larger fluctuation of ~7m. A broadband seismometer recorded strong seismic tremor in the hours leading up to each of the minor and major high stands in lake level. Spectral analysis of the tremor shows dominant frequencies in the range of ~10Hz and a fundamental harmonic frequency located in the 1Hz range. The 1Hz frequency band exhibits gliding spectral lines which increase in frequency at the end of each tremor period. Particle motion analysis of harmonic tremor waveforms indicate a ~100m upward migration of the source location from the onset of tremor until it ceases at the peak of each lake level high stand. Particle motions also indicate an azimuthal migration of the source by ~30° from the overflow outlet region of the lake toward the central vent location during the course of the tremor and lake level increase. Lake water temperature has a direct relationship with lake level and ranges between ~40°C - ~80°C. Gravity fluctuations were also continuously monitored using a Micro-g-LaCoste gPhone relative gravity meter with a 1Hz sampling rate and precision of 1 microgal. These data indicate a direct relationship between lake level and gravity showing a net increase of ~100 microgals between lake level low and high stands. A piezometer located beside the lake indicates an inflow of ground water into the subsoil during

  1. High-resolution images of tremor migrations beneath the Olympic Peninsula from stacked array of arrays seismic data

    Science.gov (United States)

    Peng, Yajun; Rubin, Allan M.

    2016-02-01

    Episodic tremor and slip (ETS) in subduction zones is generally interpreted as the manifestation of shear slip near the base of earthquake-generating portion of the plate interface. Here we devise a new method of cross-correlating stacked Array of Arrays seismic data that provides greatly improved tremor locations, a proxy for the underlying slow slip, beneath the Olympic Peninsula. This increased resolution allows us to image many features of tremor that were not visible previously. We resolve the spatial transition between the rupture zones of the inter-ETS and major ETS episodes in 2010, suggesting stress redistribution by the former. Most tremor migrations propagated along the slowly advancing main tremor front during both the inter-ETS and the major ETS episodes, even though the main front of the former deviated strongly from its usual (along-dip) orientation. We find a distinct contrast between along-dip rupture extent of large-scale rapid tremor reversals (RTRs) to the south and that to the north in our study region that anticorrelates with the locations of inter-ETS events. These RTRs originate from the main front, similar to smaller-scale RTRs previously observed at high-resolution, and many start by propagating along the main front. This could be consistent with RTRs being triggered by a cascading failure of brittle asperities. After initiation, the RTRs repeatedly occupy the same source region, and the early repetitions appear not to be tidally driven. Their stress drop may come from continuing fault weakening processes within the tremor zone, or loading by aseismic slip in surrounding regions.

  2. Postural hand tremor and incident hypertension in young to middle-aged adults: the Bogalusa heart study.

    Science.gov (United States)

    Hu, Tian; Guralnik, Jack M; Yao, Lu; Gustat, Jeanette; Harville, Emily W; Webber, Larry S; Chen, Wei; He, Jiang; Whelton, Paul K; Bazzano, Lydia A

    2016-07-01

    Hand tremor and blood pressure (BP) are both increased by adrenergic stimulation and reduced by β-blockade, indicating that they may share a common underlying pathophysiology. We prospectively examined the relationship between postural hand tremor and incident hypertension in a community-based cohort of 715 (184 blacks and 531 whites) adults without hypertension and not using medications to control tremor (e.g. β-blockers). At baseline, tremor was measured with participants holding a laser pointer aimed at a sheet of Polaroid film 8 feet away with arm outstretched for 8 s in a darkened room, and characterized by the width of the circle diameter encompassing all exposures and enumeration of exposure dots in the same area. Incident hypertension was defined as new elevation of BP (SBP ≥ 140 or DBP ≥ 90 mmHg, based on an average of six readings over two visits) or antihypertensive medication use. During a median follow-up of 6.4 years, 198 (69 blacks and 129 whites) participants developed hypertension. Tremor measurements (by quartile) were positively associated with incident hypertension after adjustment for baseline demographics, lifestyle characteristics, and BP. There was significant interaction by race (P = 0.01). Among whites, tremor was positively associated with incident hypertension [hazard ratio highest vs. lowest quartile: 2.50 (95% confidence interval: 1.40-4.48) dot method and 3.24 (1.78-5.90) circular method; both P trend hypertension. In this community-based cohort, postural hand tremor was strongly associated with the risk of incident hypertension among whites and merits further study as a potential indicator of risk for hypertension.

  3. Familial cortical myoclonic tremor and epilepsy: Description of a new South African pedigree with 30 year follow up.

    Science.gov (United States)

    van Coller, Riaan; van Rootselaar, Anne-Fleur; Schutte, Clara; van der Meyden, C H

    2017-05-01

    The aims of this study were to report the index case of a South African family with cortical myoclonic tremor and epilepsy, to describe the pedigree with the clinical findings and results of additional investigations, and to report the unique follow-up evaluation of affected and unaffected family members after 30 years. The index case led to evaluation of the clinical files of patients from 1978/1979 and clinical assessment and investigation of patients from this cohort as well as newly identified family members. Patients were examined clinically; cortical myoclonic tremor severity was scored by using the Fahn-Tolosa- Marin-Tremor Rating Scale and the Myoclonus Rating Scale. Cortical origin of myoclonus was proven. Statistical analyses were done to assess the impact of cortical myoclonic tremor on quality of life. Clinical data was available for 23 patients. Increase in cortical myoclonic tremor and age showed a statistically significant correlation with worsening of the sub-score for Quality of Life (FTMTRS) and myoclonus rating scale. After 30 years eleven of fourteen patients could be followed up. Progression of cortical myoclonic tremor severity was noted but epilepsy control was adequate with all patients reporting less than two seizures per year. No clinical features of neurodegeneration were found. We describe the initial presentation and 30 year follow-up of a four generation South African family with FCMTE. The unique long term follow up of this pedigree supports previous findings that the condition does not cause additional progressive neurological deterioration and quality of life is mostly influenced by worsening of the cortical myoclonic tremor with age. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Head and Neck

    DEFF Research Database (Denmark)

    Højgaard, Liselotte; Berthelsen, Anne Kiil; Loft, Annika

    2014-01-01

    Positron emission tomography (PET)/computed tomography with FDG of the head and neck region is mainly used for the diagnosis of head and neck cancer, for staging, treatment evaluation, relapse, and planning of surgery and radio therapy. This article is a practical guide of imaging techniques......, including a detailed protocol for FDG PET in head and neck imaging, physiologic findings, and pitfalls in selected case stories....

  5. 进展为帕金森病的特发性震颤临床特点分析%Clinical characteristic of patients with essential tremor developing Parkinson ’s disease

    Institute of Scientific and Technical Information of China (English)

    杨芬; 吕强; 张英谦; 张卫清; 陈雪涛; 石进

    2014-01-01

    目的:探讨进展为帕金森病的特发性震颤的临床特点。方法回顾性分析单纯特发性震颤患者(40例)及进展为帕金森病的特发性震颤患者(16例)的临床资料,比较2组患者的发病年龄、病程、震颤类型、震颤分布范围、小脑体征、肌肉强直等,并采用日常生活能力量表(ADL )进行生活能力评价。结果2组患者在发病年龄、性别、病程、ADL评分、小脑体征方面无显著差异。与单纯特发性震颤患者比较,进展为帕金森病的特发性震颤患者帕金森病家族史、帕金森病样症状更为常见( P<0.05)。2组患者震颤部位均以上肢常见,单纯特发性震颤患者较进展为帕金森病的特发性震颤患者姿势性或动作性震颤所占比例增高,震颤分布范围更加广泛,易累及头部、咽喉、下肢等多个部位( P<0.05)。结论进展为帕金森病的特发性震颤患者具有帕金森病样表现。%Objective To explore the clinical characteristic of patients with essential tremor developing into Parkinson ’s disease (ET-PD).Methods Forty cases with ET and sixteen cases with ET-PD were retrospectively reviewed. In the two groups , features such as age at onset ,duration ,the type of tremor ,the location of tremor ,cerebellar signs ,and rigidity were compared. ADL was used to evaluate the activity of daily living.Results T he patients in the two groups had similar age ,gender ,duration ,ADL scores and cerebrella signs. Family history of PD and signs of parkinson-ism were more common in ET-PD than ET patients(P<0.05). Upper limb tremor was common in the two groups. More ET than ET-PD had widespread postural and/or action tremor. The tremor included the head ,voice ,and legs(P<0.05).Conclusion ET-PD patients may have PD features.

  6. Time variation in amplitude-frequency distribution of deep non-volcanic tremors in the Bungo Channel region, southwest Japan

    Science.gov (United States)

    Hanakawa, Y.; Suda, N.

    2009-12-01

    Magnitude-frequency distribution of earthquakes follows the Gutenberg-Richter law. The slope of this law, b value, represents the relative occurrence of large and small earthquakes. Since magnitude is defined as corrected logarithmic amplitude, amplitude-frequency distribution of earthquakes is linear on log-log graph. On the other hand, that of non-volcanic tremors is linear on semi-log graph, indicating that it follows the exponential distribution, not the power-law distribution [Hiramatsu et al., 2008]. Thus the slope of amplitude-frequency distribution for tremors is equivalent to b value for earthquakes. In this study, we investigated time variation in the slope of amplitude-frequency distribution from analyses of tremor activities in the Bungo Channel region, where long-term slow slip events occurred in 1997 and 2003. We analyzed vertical-component records from Hi-net and the seismic networks of Japan Meteorological Agency and universities for the five-year period between 2004 and 2008. We also used records from the temporal seismic station in Hiburi Island installed by us in the period after Sept. 2004. In the Bungo Channel region, tremor activity occurs with a recurrence interval of approximately two months. We observed a total of 35 activities including small ones in the analysis period. To detect tremors and determine their hypocenters, we used the same software as Automatic Tremor Monitoring System (ATMOS) [Suda et al., in press]. We obtained frequency distribution of reduced displacements (RDs) for each tremor activity. RD is RMS amplitude of ground displacement corrected with hypocentral distance [Aki and Koyanagi, 1981], and it is proportional to seismic moment rate. The observed slopes of RD-frequency distribution for active swarms were approximately constant in the period between 2004 and 2006, but they declined in 2007. At the end of 2008, the slopes decreased bellow half the values between 2004 and 2006. As well as b value, the slope represents

  7. Constraining the thickness of tectonic tremor source region on the basis of seismological and geological observations in southwest Japan

    Science.gov (United States)

    Ohta, K.; Ito, Y.; Ujiie, K.; Fagereng, A.; Katakami, S.; Kinoshita, T.

    2016-12-01

    Recent progress in seismological observations has revealed that most of tremors and low frequency earthquakes (LFEs) along subduction zones worldwide occur as shear slips on the plate interface of subducting oceanic slab. Although the locations of tremors still have large uncertainties especially in the depth direction, in a seismological view, such tremor region is usually treated as a flat fault with no thickness. On the other hands, the recent geological observation has discovered the records of past tremors and suggested that their deformation zones have several tens of meters thickness [Ujiie et al., this meeting]. Here we try to reconcile these two observations by comparing the accurate hypocenter distribution of tremor sources based on the seismic records with the actual measurements of the thickness of anticipated tremor zones in the geological records.As representatives of tremor sources, we determine the hypocenter locations of LFEs in the Shikoku region, southwest Japan. By using the NCC hypocenter relocation method [Ohta and Ide, 2008, 2011] based on the summed cross-correlation coefficients across the network (network correlation coefficients; NCC), we accurately relocate more than 4,000 LFEs in the catalog of Japan Meteorological Agency (JMA) from 2004 to 2011. Relocated hypocenters of LFEs are highly concentrated in the depth direction and separated to several clusters on the basis of the NCC connections. Each cluster is well fitted by a single plane. The thickness of each cluster orthogonal to the plane ranges from 140m to 1.3km.For the geological measurements, we examine the tectonic mélange in the Shimanto accretionary complex in southwest Japan. The mélange shows the coexistence of shear veins and ductile shear zone, which is thought to be the zone of past episodic tremor and slip [Ujiie et al., this meeting]. We measure the distribution of shear veins in the mélange. Within the entire exposure of 100m thickness, shear veins are concentrated

  8. Remotely triggered microearthquakes and tremor in central California following the 2010 Mw 8.8 Chile earthquake

    Science.gov (United States)

    Peng, Zhigang; Hill, David P.; Shelly, David R.; Aiken, Chastity

    2010-01-01

    We examine remotely triggered microearthquakes and tectonic tremor in central California following the 2010 Mw 8.8 Chile earthquake. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest earthquake (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield-Cholame section of the San Andreas Fault (SAF). The locally triggered tremor bursts are partially masked at lower frequencies by the regionally triggered earthquake signals from Coso, but can be identified by applying high-pass or matched filters. Both triggered tremor along the SAF and the Ml 3.5 earthquake in Coso are consistent with frictional failure at different depths on critically-stressed faults under the Coulomb failure criteria. The triggered tremor, however, appears to be more phase-correlated with the surface waves than the triggered earthquakes, likely reflecting differences in constitutive properties between the brittle, seismogenic crust and the underlying lower crust.

  9. Classification of boar spermatozoid head images using a model intracellular density distribution

    NARCIS (Netherlands)

    Sánchez, Lidia; Petkov, Nicolai; Alegre, Enrique; Sanfeliu, A; Cortes, ML

    2005-01-01

    We propose a novel classification method to identify boar spermatozoid heads which present an intracellular intensity distribution similar to a model. From semen sample images, head images are isolated and normalized. We define a model intensity distribution averaging a set of head images assumed as

  10. Recency and frequency of soccer heading interact to decrease neurocognitive performance.

    Science.gov (United States)

    Webbe, Frank M; Ochs, Shelley R

    2003-01-01

    This study investigated the role of heading recency interacting with heading frequency in determining neuropsychological deficits associated with heading the ball during soccer play. Sixty-four high-ability male soccer players ages 16 to 34 completed the California Verbal Learning Test (CVLT), the Trailmaking Test, the Paced Auditory Serial Addition Test (PASAT), the Facial Recognition Test, the Rey-Osterrieth Complex Figure, and the Shipley Scales. Heading recency interacted with heading frequency, such that players with the highest self-reported estimates of heading who also experienced heading within the previous 7 days scored significantly lower on CVLT, Shipley, Trailmaking, and PASAT than other combinations of heading and recency. Although strict ball-to-head contacts could not be isolated as sufficient to cause this interaction, these results increase the weight of evidence that heading behavior is problematic for causing at least transient cognitive impairment.

  11. Head Injuries in Children

    Science.gov (United States)

    Pennington, Nicole

    2010-01-01

    School nurses play a crucial role in injury prevention and initial treatment when injuries occur at school. The role of school nurses includes being knowledgeable about the management of head injuries, including assessment and initial treatment. The school nurse must be familiar with the outcomes of a head injury and know when further evaluation…

  12. Permanent tremor of Masaya Volcano, Nicaragua: Wave field analysis and source location

    Science.gov (United States)

    MéTaxian, Jean-Philippe; Lesage, Philippe; Dorel, Jacques

    1997-10-01

    The Masaya Volcano, Nicaragua, is a basaltic caldera in a subduction zone. The permanent source of the volcanic tremor was located inside Santiago crater, at the lava lake's position and 400 m below the NE rim, and therefore corresponds to superficial magma activity. We used two tripartite arrays (90 m side), one semicircular array (r=120 m) in 1992, and two semicircular arrays (r=60 m) and a 2500 m long linear array radiating out from the source and on the flank of the crater in 1993. We used both a cross-spectrum method and a correlation method to determine the wave delay time between the reference station and the other stations of an array and to quantify the wave field. Using the delays therefore by intersecting the back azimuth wave directions from the arrays, we could pinpoint the source. Additionally, the correlation coefficients obtained as functions of frequency for the three components of motion confirm the inferred position of the source of tremor. The tremor's wave field is composed of comparable quantities of dispersed Rayleigh and Love surface waves, whose phase velocities lie in the ranges 730-1240 m/s at 2 Hz and 330-550 m/s at 6 Hz. The dispersive phase velocities were inverted to obtain crustal structures with a minimal number of layers. The resulting velocity models are similar for the northern and southern parts of the volcano. After geometrical spreading corrections, Q2Hz=14 and Q3Hz=31 were determined along the northern linear array. The typical low velocities and low Q corresponding to the cone structure and are similar to those of other basaltic volcanoes like Puu Oo, Hawaii, and Klyuchevskoy, Kamchatka.

  13. Source and path effects in the wave fields of tremor and explosions at Stromboli Volcano, Italy

    Science.gov (United States)

    Chouet, B.; Saccorotti, G.; Martini, M.; Dawson, P.; De Luca, G.; Milana, G.; Scarpa, R.

    1997-01-01

    The wave fields generated by Strombolian activity are investigated using data from small-aperture seismic arrays deployed on the north flank of Stromboli and data from seismic and pressure transducers set up near the summit crater. Measurements of slowness and azimuth as a function of time clearly indicate that the sources of tremor and explosions are located beneath the summit crater at depths shallower than 200 m with occasional bursts of energy originating from sources extending to a depth of 3 km. Slowness, azimuth, and particle motion measurements reveal a complex composition of body and surface waves associated with topography, structure, and source properties. Body waves originating at depths shallower than 200 m dominate the wave field at frequencies of 0.5-2.5 Hz, and surface waves generated by the surficial part of the source and by scattering sources distributed around the island dominate at frequencies above 2.5 Hz. The records of tremor and explosions are both dominated by SH motion. Far-field records from explosions start with radial motion, and near-field records from those events show dominantly horizontal motion and often start with a low-frequency (1-2 Hz) precursor characterized by elliptical particle motion, followed within a few seconds by a high-frequency radial phase (1-10 Hz) accompanying the eruption of pyroclastics. The dominant component of the near- and far-field particle motions from explosions, and the timing of air and body wave phases observed in the near field, are consistent with a gaspiston mechanism operating on a shallow (<200 m deep), vertical crack-like conduit. Models of a degassing fluid column suggest that noise emissions originating in the collective oscillations of bubbles ascending in the magma conduit may provide an adequate self-excitation mechanism for sustained tremor generation at Stromboli. Copyright 1997 by the American Geophysical Union.

  14. Treatment of fragile X-associated tremor ataxia syndrome (FXTAS and related neurological problems

    Directory of Open Access Journals (Sweden)

    Randi J Hagerman

    2008-06-01

    Full Text Available Randi J Hagerman1,2, Deborah A Hall3, Sarah Coffey1,2, Maureen Leehey3, James Bourgeois4, John Gould5, Lin Zhang6, Andreea Seritan4, Elizabeth Berry-Kravis7–9, John Olic