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Sample records for handheld active tremor

  1. Three-dimensional modeling of physiological tremor for hand-held surgical robotic instruments.

    Science.gov (United States)

    Tatinati, Sivanagaraja; Yan Naing Aye; Pual, Anand; Wei Tech Ang; Veluvolu, Kalyana C

    2016-08-01

    Hand-held robotic instruments are developed to compensate physiological tremor in real-time while augmenting the required precision and dexterity into normal microsurgical work-flow. The hardware (sensors and actuators) and software (causal linear filters) employed for tremor identification and filtering introduces time-varying unknown phase-delay that adversely affects the device performance. The current techniques that focus on three-dimensions (3D) tip position control involves modeling and canceling the tremor in 3-axes (x, y, and z axes) separately. Our analysis with the tremor data recorded from surgeons and novice subjects show that there exists significant correlation in tremor motion across the dimensions. Motivated by this, a new multi-dimensional modeling approach based on extreme learning machines (ELM) is proposed in this paper to correct the phase delay and to accurately model tremulous motion in three dimensions simultaneously. A study is conducted with tremor data recorded from the microsurgeons to analyze the suitability of proposed approach.

  2. Tremor

    Science.gov (United States)

    Tremors are unintentional trembling or shaking movements in one or more parts of your body. Most tremors occur in the hands. You can also have arm, head, face, vocal cord, trunk, and leg tremors. Tremors are most common in middle-aged and ...

  3. Tremor: Tremor:

    OpenAIRE

    Georgiev, Dejan; Kragelj, Veronika; Pirtošek, Zvezdan; Ribarič, Samo

    2012-01-01

    Tremor is one of the most common disorders in the population of patients diagnosed with movement disorders. In the literature we find several classifications and different types of tremors. Each tremor type has its own characteristics. The most frequently used and widely accepted tremor classification divides tremors according to clinical appearance. First, they are roughly divided into resting tremor and action tremor. Action tremor is then subdivided into postural, kinetic, intention, task ...

  4. Tremor

    Science.gov (United States)

    ... and down or closing and opening the eyes. Intention tremor is produced with purposeful movement toward a ... by any movement such as holding a heavy book or a dumbbell in the same position. top ...

  5. Tremor

    Science.gov (United States)

    ... clothes with Velcro fasteners or using button hooks Cooking or eating with utensils that have a larger handle Using a sippy cup to drink Wearing slip-on shoes and using shoehorns When to Contact a Medical Professional Call your provider if your tremor: Is worse ...

  6. Temporal Variation of Tectonic Tremor Activity Associated with Nearby Earthquakes

    Science.gov (United States)

    Chao, K.; Van der Lee, S.; Hsu, Y. J.; Pu, H. C.

    2017-12-01

    Tectonic tremor and slow slip events, located downdip from the seismogenic zone, hold the key to recurring patterns of typical earthquakes. Several findings of slow aseismic slip during the prenucletion processes of nearby earthquakes have provided new insight into the study of stress transform of slow earthquakes in fault zones prior to megathrust earthquakes. However, how tectonic tremor is associated with the occurrence of nearby earthquakes remains unclear. To enhance our understanding of the stress interaction between tremor and earthquakes, we developed an algorithm for the automatic detection and location of tectonic tremor in the collisional tectonic environment in Taiwan. Our analysis of a three-year data set indicates a short-term increase in the tremor rate starting at 19 days before the 2010 ML6.4 Jiashian main shock (Chao et al., JGR, 2017). Around the time when the tremor rate began to rise, one GPS station recorded a flip in its direction of motion. We hypothesize that tremor is driven by a slow-slip event that preceded the occurrence of the shallower nearby main shock, even though the inferred slip is too small to be observed by all GPS stations. To better quantify what the necessary condition for tremor to response to nearby earthquakes is, we obtained a 13-year ambient tremor catalog from 2004 to 2016 in the same region. We examine the spatiotemporal relationship between tremor and 37 ML>=5.0 (seven events with ML>=6.0) nearby earthquakes located within 0.5 degrees to the active tremor sources. The findings from this study can enhance our understanding of the interaction among tremor, slow slip, and nearby earthquakes in the high seismic hazard regions.

  7. Modulating basal ganglia and cerebellar activity to suppress parkinsonian tremor

    NARCIS (Netherlands)

    Heida, Tjitske; Zhao, Yan; van Wezel, Richard Jack Anton

    2013-01-01

    Despite extensive research, the detailed pathophysiology of the parkinsonian tremor is still unknown. It has been hypothesized that the generation of parkinsonian tremor is related to abnormal activity within the basal ganglia. The cerebello-thalamic-cortical loop has been suggested to indirectly

  8. An Intelligent Hand-Held Microsurgical Instrument for Improved Accuracy

    National Research Council Canada - National Science Library

    Ang, Wei

    2001-01-01

    This paper presents the development and initial experimental results of the first prototype of Micron, an active hand-held instrument to sense and compensate physiological tremor and other unwanted...

  9. Bilateral cerebellar activation in unilaterally challenged essential tremor

    NARCIS (Netherlands)

    Broersma, Marja; van der Stouwe, Anna M. M.; Buijink, Arthur W. G.; de Jong, Bauke M.; Groot, Paul F. C.; Speelman, Johannes D.; Tijssen, Marina A. J.; van Rootselaar, Anne-Fleur; Maurits, Natasha M.

    2016-01-01

    Essential tremor (ET) is one of the most common hyperkinetic movement disorders. Previous research into the pathophysiology of ET suggested underlying cerebellar abnormalities. In this study, we added electromyography as an index of tremor intensity to functional Magnetic Resonance Imaging

  10. Multiple Seismic Array Observations for Tracing Deep Tremor Activity in Western Shikoku, Japan

    Science.gov (United States)

    Takeda, T.; Matsuzawa, T.; Shiomi, K.; Obara, K.

    2011-12-01

    Deep non-volcanic tremors become very active during episodic slow-slip events in western Japan and Cascadia. The episodic tremor and slow-slip events in western Shikoku, Japan, occur at a typical interval of 6 months. Recently, it has been reported that tremor migration activity is complex and shows different migrating directions depending on time scales (Ghosh et al., 2010). Such characteristics of tremor are important to understand the mechanism of tremor and the relationship between tremor and SSEs. However it is difficult to determine the location of tremors with high accuracy because tremors show faint signals and make the identification of P/S-wave arrivals difficult. Seismic array analysis is useful to evaluate tremor activity, especially to estimate the arrival direction of seismic energy (e.g. Ueno et al., 2010, Ghosh et al., 2010), as it can distinguish multiple tremor sources occurring simultaneously. Here, we have conducted seismic array observation and analyzed seismic data during tremor activity by applying the MUSIC method to trace tremor location and its migration in western Shikoku. We have installed five seismic arrays in western Shikoku since January 2011. One of the arrays contains 30 stations with 3-component seismometers with a natural frequency of 2 Hz (Type-L array). The array aperture size is 2 km and the mean interval between stations is approximately 200 m. Each of the other arrays (Type-S array) contains 9 seismic stations with the same type of seismometers of the Type-L array, and is deployed surrounding the Type-L array. The small array aperture size is 800 m and its mean station interval is approximately 150 m. All array stations have recorded continuous waveform data at a sampling of 200Hz. In May 2011, an episodic tremor and a short-term slip event occurred for the first time during the observation period. We could retrieve the array seismic data during the whole tremor episode. The analysis of data from the type-L array confirms

  11. The nature of tremor circuits in parkinsonian and essential tremor

    Science.gov (United States)

    Cagnan, Hayriye; Little, Simon; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Cheeran, Binith; Fitzgerald, James; Green, Alexander L.; Aziz, Tipu

    2014-01-01

    Tremor is a cardinal feature of Parkinson’s disease and essential tremor, the two most common movement disorders. Yet, the mechanisms underlying tremor generation remain largely unknown. We hypothesized that driving deep brain stimulation electrodes at a frequency closely matching the patient’s own tremor frequency should interact with neural activity responsible for tremor, and that the effect of stimulation on tremor should reveal the role of different deep brain stimulation targets in tremor generation. Moreover, tremor responses to stimulation might reveal pathophysiological differences between parkinsonian and essential tremor circuits. Accordingly, we stimulated 15 patients with Parkinson’s disease with either thalamic or subthalamic electrodes (13 male and two female patients, age: 50–77 years) and 10 patients with essential tremor with thalamic electrodes (nine male and one female patients, age: 34–74 years). Stimulation at near-to tremor frequency entrained tremor in all three patient groups (ventrolateral thalamic stimulation in Parkinson’s disease, P = 0.0078, subthalamic stimulation in Parkinson’s disease, P = 0.0312; ventrolateral thalamic stimulation in essential tremor, P = 0.0137; two-tailed paired Wilcoxon signed-rank tests). However, only ventrolateral thalamic stimulation in essential tremor modulated postural tremor amplitude according to the timing of stimulation pulses with respect to the tremor cycle (e.g. P = 0.0002 for tremor amplification, two-tailed Wilcoxon rank sum test). Parkinsonian rest and essential postural tremor severity (i.e. tremor amplitude) differed in their relative tolerance to spontaneous changes in tremor frequency when stimulation was not applied. Specifically, the amplitude of parkinsonian rest tremor remained unchanged despite spontaneous changes in tremor frequency, whereas that of essential postural tremor reduced when tremor frequency departed from median values. Based on these results we conclude that

  12. 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.

  13. Effect of nipradilol, a beta-adrenergic blocker with vasodilating activity, on oxotremorine-induced tremor in mice.

    Science.gov (United States)

    Iwata, S; Nomoto, M; Fukuda, T

    1996-10-01

    The effect of nipradilol, a nonselective beta-adrenergic receptor blocker with nitroglycerin-like vasodilating activity, on oxotremorine-induced tremor was studied in mice. General tremor in mice was elicited by 0.5 mg/kg oxotremorine. The tremor was quantified using a capacitance transducer, then analyzed by a signal processor. The strength of the tremor was expressed in "points". The point values of the tremor (mean +/- SE) in control mice for 5 mg/kg (+/-)-propranolol, 2.5 mg/kg arotinolol, 0.5 mg/kg nipradilol, 1.0 mg/kg nipradilol and 2.5 mg/kg nipradilol were 87 +/- 16, 42 +/- 6, 38 +/- 6, 99 +/- 28, 28 +/- 6 and 31 +/- 7, respectively. The strength of the tremor was reduced by all beta-blockers. Although 1.0 mg/kg nipradilol significantly reduced the tremor, further inhibition of the tremor was not obtained with dosages up to 2.5 mg/kg of the drug. In conclusion, nipradilol was effective for suppressing oxotremorine-induced tremor, as were other beta-blockers.

  14. Essential Tremor

    Science.gov (United States)

    ... Treatment There is no definitive cure for essential tremor. Symptomatic drug therapy may include propranolol or other beta blockers and primidone, an anticonvulsant drug. Eliminating tremor "triggers" ...

  15. Energy Cost of Active and Sedentary Music Video Games: Drum and Handheld Gaming vs. Walking and Sitting.

    Science.gov (United States)

    Miranda, Edwin; Overstreet, Brittany S; Fountain, William A; Gutierrez, Vincent; Kolankowski, Michael; Overstreet, Matthew L; Sapp, Ryan M; Wolff, Christopher A; Mazzetti, Scott A

    2017-01-01

    To compare energy expenditure during and after active and handheld video game drumming compared to walking and sitting. Ten experienced, college-aged men performed four protocols (one per week): no-exercise seated control (CTRL), virtual drumming on a handheld gaming device (HANDHELD), active drumming on drum pads (DRUM), and walking on a treadmill at ~30% of VO 2max (WALK). Protocols were performed after an overnight fast, and expired air was collected continuously during (30min) and after (30min) exercise. DRUM and HANDHELD song lists, day of the week, and time of day were identical for each participant. Significant differences (p DRUM > HANDHELD. No significant differences in the rates of energy expenditure among groups during recovery were observed. Total energy expenditure was significantly greater (p < 0.05) during WALK (149.5 ± 30.6 kcal) compared to DRUM (118.7 ± 18.8 kcal) and HANDHELD (44.9±11.6 kcal), and greater during DRUM compared to HANDHELD. Total energy expenditure was not significantly different between HANDHELD (44.9 ± 11.6 kcal) and CTRL (38.2 ± 6.0 kcal). Active video game drumming at expert-level significantly increased energy expenditure compared to handheld, but it hardly met moderate-intensity activity standards, and energy expenditure was greatest during walking. Energy expenditure with handheld video game drumming was not different from no-exercise control. Thus, traditional aerobic exercise remains at the forefront for achieving the minimum amount and intensity of physical activity for health, individuals desiring to use video games for achieving weekly physical activity recommendations should choose games that require significant involvement of lower-body musculature, and time spent playing sedentary games should be a limited part of an active lifestyle.

  16. Active case finding strategy for chronic obstructive pulmonary disease with handheld spirometry.

    Science.gov (United States)

    Kim, Joo Kyung; Lee, Chang Min; Park, Ji Young; Kim, Joo Hee; Park, Sung-Hoon; Jang, Seung Hun; Jung, Ki-Suck; Yoo, Kwang Ha; Park, Yong Bum; Rhee, Chin Kook; Kim, Deog Kyeom; Hwang, Yong Il

    2016-12-01

    The early detection and diagnosis of chronic obstructive pulmonary disease (COPD) is critical to providing appropriate and timely treatment. We explored a new active case-finding strategy for COPD using handheld spirometry.We recruited subjects over 40 years of age with a smoking history of more than 10 pack-years who visited a primary clinic complaining of respiratory symptoms. A total of 190 of subjects were enrolled. Medical information was obtained from historical records and physical examination by general practitioners. All subjects had their pulmonary function evaluated using handheld spirometry with a COPD-6 device. Because forced expiratory volume in 6 seconds (FEV6) has been suggested as an alternative to FVC, we measured forced expiratory volume in 1 second (FEV1)/FEV6 for diagnosis of airflow limitation. All subjects were then referred to tertiary referral hospitals to complete a "Could it be COPD?" questionnaire, handheld spiromtery, and conventional spirometry. The results of each instrument were compared to evaluate the efficacy of both handheld spirometry and the questionnaire.COPD was newly diagnosed in 45 (23.7%) patients. According to our receiver-operating characteristic (ROC) curve analysis, sensitivity and specificity were maximal when the FEV1/FEV6 ratio was less than 77%. The area under the ROC curve was 0.759. The sensitivity, specificity, positive predictive value, and negative predictive value were 72.7%, 77.1%, 50%, and 90%, respectively. The area under the ROC curve of respiratory symptoms listed on the questionnaire ranged from 0.5 to 0.65, which indicates that there is almost no difference compared with the results of handheld spirometry.The present study demonstrated the efficacy of handheld spirometry as an active case-finding tool for COPD in a primary clinical setting. This study suggested that physicians should recommend handheld spirometry for people over the age of 40, who have a smoking history of more than 10 pack

  17. Essential tremor

    Science.gov (United States)

    ... such as: Smoking and smokeless tobacco Overactive thyroid ( hyperthyroidism ) Suddenly stopping alcohol after drinking a lot for ... from the medicines used to treat your tremor Prevention Alcoholic beverages in small quantities may decrease tremors. ...

  18. Backprojection of volcanic tremor

    Science.gov (United States)

    Haney, Matthew M.

    2014-01-01

    Backprojection has become a powerful tool for imaging the rupture process of global earthquakes. We demonstrate the ability of backprojection to illuminate and track volcanic sources as well. We apply the method to the seismic network from Okmok Volcano, Alaska, at the time of an escalation in tremor during the 2008 eruption. Although we are able to focus the wavefield close to the location of the active cone, the network array response lacks sufficient resolution to reveal kilometer-scale changes in tremor location. By deconvolving the response in successive backprojection images, we enhance resolution and find that the tremor source moved toward an intracaldera lake prior to its escalation. The increased tremor therefore resulted from magma-water interaction, in agreement with the overall phreatomagmatic character of the eruption. Imaging of eruption tremor shows that time reversal methods, such as backprojection, can provide new insights into the temporal evolution of volcanic sources.

  19. Functional tremor.

    Science.gov (United States)

    Schwingenschuh, P; Deuschl, G

    2016-01-01

    Functional tremor is the commonest reported functional movement disorder. A confident clinical diagnosis of functional tremor is often possible based on the following "positive" criteria: a sudden tremor onset, unusual disease course, often with fluctuations or remissions, distractibility of the tremor if attention is removed from the affected body part, tremor entrainment, tremor variability, and a coactivation sign. Many patients show excessive exhaustion during examination. Other somatizations may be revealed in the medical history and patients may show additional functional neurologic symptoms and signs. In cases where the clinical diagnosis remains challenging, providing a "laboratory-supported" level of certainty aids an early positive diagnosis. In rare cases, in which the distinction from Parkinson's disease is difficult, dopamine transporter single-photon emission computed tomography (DAT-SPECT) can be indicated. © 2016 Elsevier B.V. All rights reserved.

  20. Defining Dystonic Tremor

    OpenAIRE

    Elble, Rodger J

    2013-01-01

    A strong association between dystonia and tremor has been known for more than a century. Two forms of tremor in dystonia are currently recognized: 1) dystonic tremor, which is tremor produced by dystonic muscle contraction and 2) tremor associated with dystonia, which is tremor in a body part that is not dystonic, but there is dystonia elsewhere. Both forms of tremor in dystonia frequently resemble essential tremor or another pure tremor syndrome (e.g., isolated head and voice tremors and tas...

  1. Streaking tremor in Cascadia

    Science.gov (United States)

    Vidale, J. E.; Ghosh, A.; Sweet, J. R.; Creager, K. C.; Wech, A.; Houston, H.

    2009-12-01

    Details of tremor deep in subduction zones is damnably difficult to glimpse because of the lack of crisp initial arrivals, low waveform coherence, uncertain focal mechanisms, and the probability of simultaneous activity across extended regions. Yet such details hold out the best hope to illuminate the unknown mechanisms underlying episodic tremor and slip. Attacking this problem with brute force, we pointed a small, very dense seismic array down at the migration path of a good-sized episodic tremor and slip (ETS) event. In detail, it was an 84-element, 1300-m-aperture temporary seismic array in northern Washington, and the migration path of the May 2008 ETS event was 30-40 km directly underneath. Our beamforming technique tracked the time, incident angle, and azimuth of tremor radiation in unprecedented detail. We located the tremor by assuming it occurs on the subduction interface, estimated relative tremor moment released by each detected tremor window, and mapped it on the interface [Ghosh et al., GRL, 2009]. Fortunately for our ability to image it, the tremor generally appears to emanate from small regions, and we were surprised by how steadily the regions migrated with time. For the first time in Cascadia, we found convergence-parallel transient streaks of tremor migrating at velocities of several tens of km/hr, with movement in both up- and down-dip directions. Similar patterns have been seen in Japan [Shelly, G3, 2007]. This is in contrast to the long-term along-strike marching of tremor at 10 km/day. These streaks tend to propagate steadily and often repeat the same track on the interface multiple times. They light up persistent moment patches on the interface by a combination of increased amplitude and longer residence time within the patches. The up- and down-dip migration dominates the 2 days of tremor most clearly imaged by our array. The tendency of the streaks to fill in bands is the subject of the presentation of Ghosh et al. here. The physical

  2. Nonvolcanic Tremor Activity is Highly Correlated With Slow Slip Events, Mexico

    Science.gov (United States)

    Kostoglodov, V.; Shapiro, N.; Larson, K. M.; Payero, J. S.; Husker, A.; Santiago, L. A.; Clayton, R. W.

    2008-12-01

    Significant activity of nonvolcanic tremor (NVT) has been observed in the central Mexico (Guerrero) subduction zone since 2001 when continuous seismic records became available. Although the quality of these records is poor, it is possible to estimate a temporal variation of energy in the range of 1-2Hz (best signal/noise ratio for the NVT). These clearly indicate a maximum of NVT energy release (En) during the 2001-2002 and 2006 large aseismic slow slip events (SSE) registered by the Guerrero GPS network. In particular En is higher for the 2001-2002 SSE which had larger surface displacements and extension than the 2006 SSE. A more detailed and accurate study of NVT activity was carried out using the data collected during the MASE experiment in Mexico. MASE consisted of 100 broad band seismometers in operation for ~2.5 years (2005-2007) along the profile oriented SSW-NNE from Acapulco, and crossing over the subduction zone for a distance of ~500 km. Epicenters and depths of individual tremor events determined using the envelope cross-correlation technique have rather large uncertainties, partly originated from the essentially 2D geometry of the network. The 'energy' approach is more efficient in this case because it provides an average NVT activity evolution in time and space. The data processing consists of a band pass (1-2Hz) filter of the raw 100 Hz sampled N-S component records, application a 10 min-width median filter to eliminate the effect of local seismic events and noise, and integration of the energy and normalization of daily En using an average coda amplitude from several regional earthquakes of M~5. A time-space distribution of En reveals a strong correlation between NVT energy release and the 2006 SSE, which also replicates the two-phase character of this slow event and a migration of the slow slip maximum from North to South. There are also a few clear episodes of relatively high NVT energy release that do not correspond to any significant geodetic

  3. The many roads to tremor.

    Science.gov (United States)

    Brittain, John-Stuart; Brown, Peter

    2013-12-01

    Tremor represents one of the most prominent examples of aberrant synchronisation within the human motor system, and Essential Tremor (ET) is by far the most common tremor disorder. Yet, even within ET there is considerable variation, and patients may have contrasting amounts of postural and intention tremor. Recently, Pedrosa et al. (2013) challenged tremor circuits in a cohort of patients presenting with ET, by applying low-frequency deep brain stimulation within thalamus. This interventional approach provided strong evidence that distinct (yet possibly overlapping) neural substrates are responsible for postural and intention tremor in ET. Intention tremor, and not postural tremor, was exacerbated by low frequency stimulation, and the effect was localised in the region of the ventrolateral thalamus in such a way as to implicate cerebello-thalamic pathways. These results, taken in conjunction with the contemporary literature, reveal that pathological changes exaggerate oscillatory synchrony in selective components of an extensive and distributed motor network, and that synchronisation within these networks is further regulated according to motor state. Through a combination of pathological and more dynamic physiological factors, activity then spills out into the periphery in the form of tremor. The findings of Pedrosa et al. (2013) are timely as they coincide with an emerging notion that tremor may result through selective dysregulation within a broader tremorgenic network. © 2013.

  4. Thalamic physiology of intentional essential tremor is more like cerebellar tremor than postural essential tremor

    OpenAIRE

    Zakaria, R; Lenz, FA; Hua, S; Avin, BH; Liu, CC; Mari, Z

    2013-01-01

    The neuronal physiological correlates of clinical heterogeneity in human essential tremor are unknown. We now test the hypothesis that thalamic neuronal and EMG activities during intention essential tremor are similar to those of the intention tremor which is characteristic of cerebellar lesions. Thalamic neuronal firing was studied in a cerebellar relay nucleus (ventral intermediate, Vim) and in a pallidal relay nucleus (ventral oral posterior, Vop) during stereotactic surgery for the treatm...

  5. Essential Tremor Is More Than a Tremor

    Science.gov (United States)

    ... Giving Options Donate Prev Next IETF > About Essential Tremor > Video Video Click to share on Facebook (Opens ... Click to print (Opens in new window) Essential Tremor is More Than a Tremor Providing a voice ...

  6. Essential Tremor Is More Than a Tremor

    Medline Plus

    Full Text Available ... Giving Options Donate Prev Next IETF > About Essential Tremor > Video Video Click to share on Facebook (Opens ... Click to print (Opens in new window) Essential Tremor is More Than a Tremor Providing a voice ...

  7. Tracing tremor: Neural correlates of essential tremor and its treatment

    NARCIS (Netherlands)

    Buijink, A.W.G.

    2016-01-01

    This thesis focusses on the neural correlates and treatment of the neurological movement disorder essential tremor (ET). ET, one of the most common movement disorders in clinical neurology, is characterized by an action and intention tremor of mainly the hands, hampering daily life activities.

  8. Long-term detection of Parkinsonian tremor activity from subthalamic nucleus local field potentials.

    Science.gov (United States)

    Houston, Brady; Blumenfeld, Zack; Quinn, Emma; Bronte-Stewart, Helen; Chizeck, Howard

    2015-01-01

    Current deep brain stimulation paradigms deliver continuous stimulation to deep brain structures to ameliorate the symptoms of Parkinson's disease. This continuous stimulation has undesirable side effects and decreases the lifespan of the unit's battery, necessitating earlier replacement. A closed-loop deep brain stimulator that uses brain signals to determine when to deliver stimulation based on the occurrence of symptoms could potentially address these drawbacks of current technology. Attempts to detect Parkinsonian tremor using brain signals recorded during the implantation procedure have been successful. However, the ability of these methods to accurately detect tremor over extended periods of time is unknown. Here we use local field potentials recorded during a deep brain stimulation clinical follow-up visit 1 month after initial programming to build a tremor detection algorithm and use this algorithm to detect tremor in subsequent visits up to 8 months later. Using this method, we detected the occurrence of tremor with accuracies between 68-93%. These results demonstrate the potential of tremor detection methods for efficacious closed-loop deep brain stimulation over extended periods of time.

  9. Support System to Improve Reading Activity in Parkinson’s Disease and Essential Tremor Patients

    Directory of Open Access Journals (Sweden)

    Franklin Parrales Bravo

    2017-05-01

    Full Text Available The use of information and communication technologies (ICTs to improve the quality of life of people with chronic and degenerative diseases is a topic receiving much attention nowadays. We can observe that new technologies have driven numerous scientific projects in e-Health, encompassing Smart and Mobile Health, in order to address all the matters related to data processing and health. Our work focuses on helping to improve the quality of life of people with Parkinson’s Disease (PD and Essential Tremor (ET by means of a low-cost platform that enables them to read books in an easy manner. Our system is composed of two robotic arms and a graphical interface developed for Android platforms. After several tests, our proposal has achieved a 96.5% accuracy for A4 80 gr non-glossy paper. Moreover, our system has outperformed the state-of-the-art platforms considering different types of paper and inclined surfaces. The feedback from ET and PD patients was collected at “La Princesa” University Hospital in Madrid and was used to study the user experience. Several features such as ease of use, speed, correct behavior or confidence were measured via patient feedback, and a high level of satisfaction was awarded to most of them. According to the patients, our system is a promising tool for facilitating the activity of reading.

  10. Unusual Forehead Tremor in Four Patients with Essential Tremor

    OpenAIRE

    Gascón-Bayarri, Jordi; Campdelacreu, Jaume; Calopa, Màtil; Jaumà, Serge; Bau, Laura; Povedano, Mònica; Montero, Jordi

    2012-01-01

    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.

  11. Unusual Forehead Tremor in Four Patients with Essential Tremor

    Directory of Open Access Journals (Sweden)

    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.

  12. Handheld juggernaut.

    Science.gov (United States)

    Hagland, Mark

    2010-08-01

    Not only are hospital, health system, and medical group ClOs and clinical informaticists deploying handheld mobile devices across their enterprises as clinical computing tools; clinicians, especially physicians, are increasingly bringing their own BlackBerrys, iPhones, iPads, Android devices, and other handhelds, into patient care organizations for their personal clinical use. Not surprisingly, the challenges--as well as the opportunities--are multilayered and complex, and include the strategic planning, infrastructure, clinician preference, clinician workflow, and security issues involved in the emerging mobile handheld revolution. The diversity of approaches among ClOs and other healthcare IT leaders on such issues is striking, and underscores the need for flexibility and nimbleness going forward.

  13. Harmaline Tremor: Underlying Mechanisms in a Potential Animal Model of Essential Tremor

    Directory of Open Access Journals (Sweden)

    Adrian Handforth

    2012-09-01

    Full Text Available Background: Harmaline and harmine are tremorigenic β-carbolines that, on administration to experimental animals, induce an acute postural and kinetic tremor of axial and truncal musculature. This drug-induced action tremor has been proposed as a model of essential tremor. Here we review what is known about harmaline tremor.Methods: Using the terms harmaline and harmine on PubMed, we searched for papers describing the effects of these β-carbolines on mammalian tissue, animals, or humans.Results: Investigations over four decades have shown that harmaline induces rhythmic burst-firing activity in the medial and dorsal accessory inferior olivary nuclei that is transmitted via climbing fibers to Purkinje cells and to the deep cerebellar nuclei, then to brainstem and spinal cord motoneurons. The critical structures required for tremor expression are the inferior olive, climbing fibers, and the deep cerebellar nuclei; Purkinje cells are not required. Enhanced synaptic norepinephrine or blockade of ionic glutamate receptors suppresses tremor, whereas enhanced synaptic serotonin exacerbates tremor. Benzodiazepines and muscimol suppress tremor. Alcohol suppresses harmaline tremor but exacerbates harmaline-associated neural damage. Recent investigations on the mechanism of harmaline tremor have focused on the T-type calcium channel.Discussion: Like essential tremor, harmaline tremor involves the cerebellum, and classic medications for essential tremor have been found to suppress harmaline tremor, leading to utilization of the harmaline model for preclinical testing of antitremor drugs. Limitations are that the model is acute, unlike essential tremor, and only approximately half of the drugs reported to suppress harmaline tremor are subsequently found to suppress tremor in clinical trials.

  14. Tectonic tremor

    Science.gov (United States)

    Shelly, David R.

    2016-01-01

    Tectonic, non-volcanic tremor is a weak vibration of ground, which cannot be felt by humans but can be detected by sensitive seismometers. It is defined empirically as a low-amplitude, extended duration seismic signal associated with the deep portion (∼20–40 km depth) of some major faults. It is typically observed most clearly in the frequency range of 2–8 Hz and is depleted in energy at higher frequencies relative to regular earthquakes.

  15. Tremor in dystonia.

    Science.gov (United States)

    Pandey, Sanjay; Sarma, Neelav

    2016-08-01

    Tremor has been recognized as an important clinical feature in dystonia. Tremor in dystonia may occur in the body part affected by dystonia known as dystonic tremor or unaffected body regions known as tremor associated with dystonia. The most common type of tremor seen in dystonia patients is postural and kinetic which may be mistaken for familial essential tremor. Similarly familial essential tremor patients may have associated dystonia leading to diagnostic uncertainties. The pathogenesis of tremor in dystonia remains speculative, but its neurophysiological features are similar to dystonia which helps in differentiating it from essential tremor patients. Treatment of tremor in dystonia depends upon the site of involvement. Dystonic hand tremor is treated with oral pharmacological therapy and dystonic head, jaw and voice tremor is treated with injection botulinum toxin. Neurosurgical interventions such as deep brain stimulation and lesion surgery should be an option in patients not responding to the pharmacological treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Akinetic-rigid and tremor-dominant Parkinson's disease patients show different patterns of intrinsic brain activity.

    Science.gov (United States)

    Zhang, Jiuquan; Wei, Luqing; Hu, Xiaofei; Xie, Bing; Zhang, Yanling; Wu, Guo-Rong; Wang, Jian

    2015-01-01

    Parkinson's disease (PD) is a surprisingly heterogeneous neurodegenerative disorder. It is well established that different subtypes of PD present with different clinical courses and prognoses. However, the neural mechanism underlying these disparate presentations is uncertain. Here we used resting-state fMRI (rs-fMRI) and the regional homogeneity (ReHo) method to determine neural activity patterns in the two main clinical subgroups of PD (akinetic-rigid and tremor-dominant). Compared with healthy controls, akinetic-rigid (AR) subjects had increased ReHo mainly in right amygdala, left putamen, bilateral angular gyrus, bilateral medial prefrontal cortex (MPFC), and decreased ReHo in left post cingulate gyrus/precuneus (PCC/PCu) and bilateral thalamus. In contrast, tremor-dominant (TD) patients showed higher ReHo mostly in bilateral angular gyrus, left PCC, cerebellum_crus1, and cerebellum_6, while ReHo was decreased in right putamen, primary sensory cortex (S1), vermis_3, and cerebellum_4_5. These results indicate that AR and TD subgroups both represent altered spontaneous neural activity in default-mode regions and striatum, and AR subjects exhibit more changed neural activity in the mesolimbic cortex (amygdala) but TD in the cerebellar regions. Of note, direct comparison of the two subgroups revealed a distinct ReHo pattern primarily located in the striatal-thalamo-cortical (STC) and cerebello-thalamo-cortical (CTC) loops. Overall, our findings highlight the involvement of default mode network (DMN) and STC circuit both in AR and TD subtypes, but also underscore the importance of integrating mesolimbic-striatal and CTC loops in understanding neural systems of akinesia and rigidity, as well as resting tremor in PD. This study provides improved understanding of the pathophysiological models of different subtypes of PD. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Thalamic Deep Brain Stimulation for Essential Tremor Also Reduces Voice Tremor.

    Science.gov (United States)

    Kundu, Bornali; Schrock, Lauren; Davis, Tyler; House, Paul A

    2017-12-12

    Voice tremor is a common feature of essential tremor (ET) that is difficult to treat medically and significantly affects quality of life. Deep brain stimulation (DBS) of the ventral intermediate nucleus (Vim) of the thalamus is effective in improving contralateral distal limb tremor and has been shown in limited studies to affect voice tremor. Our objective was to retrospectively evaluate whether Vim-DBS used to treat patients with essential motor tremor also effectively treated underlying concurrent voice tremor and assess whether particular lead locations were favorable for treating vocal tremor. In this retrospective cohort study, patients had unilateral or bilateral lead placement and were monitored for up to 12 months. We used the Fahn-Tolosa-Marin (FTM) subscore to assess vocal tremor. Changes in vocal tremor before and after stimulation and over several sessions were assessed. Of the 77 patients who met the inclusion criteria and were treated for essential tremor, 20 (26%) patients had vocal tremor prior to stimulation. Active Vim-DBS decreased the amplitude of voice tremor by 80% (p centroid of stimulation showed that Vim thalamic stimulation that is more anterior on average yielded better voice tremor control, significantly so on the left side (p < 0.05). Additionally, there was improvement in head, tongue, and face tremor scores (p < 0.05). Unilateral and bilateral Vim-DBS targeted to treat the motor component of essential tremor also dramatically decreased the amplitude of voice tremor in this group of patients, suggesting a potential benefit of this treatment for affected patients. © 2017 International Neuromodulation Society.

  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 > ... Mild Hereditary Tremor No Big Deal 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 ... More Than a Tremor Providing a voice for people with essential tremor means also reaching out to ... six-minute video tells the stories of six people living with ET. It goes beyond diagnosis and ...

  20. 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 > ... for Grants Relevant to Essential Tremor IETF Champion Home About the IETF Volunteer For Healthcare Providers Giving ...

  1. Unusual Wrist Tremor: Unilateral Isometric Tremor?

    Directory of Open Access Journals (Sweden)

    Theresa A. Zesiewicz

    2014-01-01

    Full Text Available Background: Tremors may be difficult to classify.Case Report: An 83‐year‐old male presented with an unusual left wrist tremor. The tremor could be reproducibly elicited by making a fist or carrying a weighted object (e.g., a shopping bag, bottle of water of approximately 1 lb or more, and it intensified with heavier weights. The tremor was difficult to classify, although it shared features with isometric tremor.Discussion: This specific presentation of tremor has not been reported previously. We hope that the detailed description we provide will aid other neurologists who encounter this or similar tremors in their clinics.

  2. Beyond mere information provisioning: a handheld museum guide based on social activities and playful learning

    OpenAIRE

    SCHROYEN, Jolien; GABRIELS, Kris; TEUNKENS, Daniel; ROBERT, Karel; LUYTEN, Kris; CONINX, Karin

    2007-01-01

    During a museum visit, social interaction can improve intellectual, social, personal and cultural development. With the advances in technology, the use of personal mobile handheld devices – such as Personal Digital Assistants (PDAs) – that replace the traditional paper guidebooks is becoming a common sight at various heritage sites all over the world. This technology often leads to problems such as isolating visitors from their companions and distracting visitors away from their surroundings....

  3. The role of propriospinal neuronal network in transmitting the alternating muscular activities of flexor and extensor in parkinsonian tremor.

    Science.gov (United States)

    Hao, M; He, X; Lan, N

    2012-01-01

    It has been shown that normal cyclic movement of human arm and resting limb tremor in Parkinson's disease (PD) are associated with the oscillatory neuronal activities in different cerebral networks, which are transmitted to the antagonistic muscles via the same spinal pathway. There are mono-synaptic and multi-synaptic corticospinal pathways for conveying motor commands. This study investigates the plausible role of propriospinal neuronal (PN) network in the C3-C4 levels in multi-synaptic transmission of cortical commands for oscillatory movements. A PN network model is constructed based on known neurophysiological connections, and is hypothesized to achieve the conversion of cortical oscillations into alternating antagonistic muscle bursts. Simulations performed with a virtual arm (VA) model indicate that without the PN network, the alternating bursts of antagonistic muscle EMG could not be reliably generated, whereas with the PN network, the alternating pattern of bursts were naturally displayed in the three pairs of antagonist muscles. Thus, it is suggested that oscillations in the primary motor cortex (M1) of single and double tremor frequencies are processed at the PN network to compute the alternating burst pattern in the flexor and extensor muscles.

  4. Seismic wave triggering of nonvolcanic tremor, episodic tremor and slip, and earthquakes on Vancouver Island

    Science.gov (United States)

    Rubinstein, Justin L.; Gomberg, Joan; Vidale, John E.; Wech, Aaron G.; Kao, Honn; Creager, Kenneth C.; Rogers, Garry

    2009-02-01

    We explore the physical conditions that enable triggering of nonvolcanic tremor and earthquakes by considering local seismic activity on Vancouver Island, British Columbia during and immediately after the arrival of large-amplitude seismic waves from 30 teleseismic and 17 regional or local earthquakes. We identify tremor triggered by four of the teleseismic earthquakes. The close temporal and spatial proximity of triggered tremor to ambient tremor and aseismic slip indicates that when a fault is close to or undergoing failure, it is particularly susceptible to triggering of further events. The amplitude of the triggering waves also influences the likelihood of triggering both tremor and earthquakes such that large amplitude waves triggered tremor in the absence of detectable aseismic slip or ambient tremor. Tremor and energy radiated from regional/local earthquakes share the same frequency passband so that tremor cannot be identified during these smaller, more frequent events. We confidently identify triggered local earthquakes following only one teleseism, that with the largest amplitude, and four regional or local events that generated vigorous aftershock sequences in their immediate vicinity. Earthquakes tend to be triggered in regions different from tremor and with high ambient seismicity rates. We also note an interesting possible correlation between large teleseismic events and episodic tremor and slip (ETS) episodes, whereby ETS events that are "late" and have built up more stress than normal are susceptible to triggering by the slight nudge of the shaking from a large, distant event, while ETS events that are "early" or "on time" are not.

  5. Pallidal Dysfunction Drives a Cerebellothalamic Circuit into Parkinson Tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Janssen, M.J.R.; Oyen, W.J.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    Objective: Parkinson disease (PD) is characterized by striatal dopamine depletion, which explains clinical symptoms such as bradykinesia and rigidity, but not resting tremor. Instead, resting tremor is associated with increased activity in a distinct cerebellothalamic circuit. To date, it remains

  6. Pallidal dysfunction drives a cerebellothalamic circuit into Parkinson tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Janssen, M.J.; Oyen, W.J.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    OBJECTIVE: Parkinson disease (PD) is characterized by striatal dopamine depletion, which explains clinical symptoms such as bradykinesia and rigidity, but not resting tremor. Instead, resting tremor is associated with increased activity in a distinct cerebellothalamic circuit. To date, it remains

  7. Linking Essential Tremor to the Cerebellum-Animal Model Evidence.

    Science.gov (United States)

    Handforth, Adrian

    2016-06-01

    In this review, we hope to stimulate interest in animal models as opportunities to understand tremor mechanisms within the cerebellar system. We begin by considering the harmaline model of essential tremor (ET), which has ET-like anatomy and pharmacology. Harmaline induces the inferior olive (IO) to burst fire rhythmically, recruiting rhythmic activity in Purkinje cells (PCs) and deep cerebellar nuclei (DCN). This model has fostered the IO hypothesis of ET, which postulates that factors that promote excess IO, and hence PC complex spike synchrony, also promote tremor. In contrast, the PC hypothesis postulates that partial PC cell loss underlies tremor of ET. We describe models in which chronic partial PC loss is associated with tremor, such as the Weaver mouse, and others with PC loss that do not show tremor, such as the Purkinje cell degeneration mouse. We postulate that partial PC loss with tremor is associated with terminal axonal sprouting. We then discuss tremor that occurs with large lesions of the cerebellum in primates. This tremor has variable frequency and is an ataxic tremor not related to ET. Another tremor type that is not likely related to ET is tremor in mice with mutations that cause prolonged synaptic GABA action. This tremor is probably due to mistiming within cerebellar circuitry. In the final section, we catalog tremor models involving neurotransmitter and ion channel perturbations. Some appear to be related to the IO hypothesis of ET, while in others tremor may be ataxic or due to mistiming. In summary, we offer a tentative framework for classifying animal action tremor, such that various models may be considered potentially relevant to ET, subscribing to IO or PC hypotheses, or not likely relevant, as with mistiming or ataxic tremor. Considerable further research is needed to elucidate the mechanisms of tremor in animal models.

  8. Handheld Micromanipulator for Robot-Assisted Stapes Footplate Surgery

    Science.gov (United States)

    Grande, Gonzalo Montes; Knisely, Anna J.; Becker, Brian C.; Yang, Sungwook; Hirsch, Barry E.; Riviere, Cameron N.

    2012-01-01

    Stapes footplate surgery is complex and delicate. This surgery is carried out in the middle ear to improve hearing. High accuracy is required to avoid critical tissues and structures near the surgical worksite. By suppressing the surgeon’s tremor during the operation, accuracy can be improved. In this paper, a fully handheld active micromanipulator known as Micron is evaluated for its feasibility for this delicate operation. An ergonomic handle, a custom tip, and a brace attachment were designed for stapes footplate surgery and tested in a fenestration task through a fixed speculum. Accuracy was measured during simulated surgery in two different scenarios: Micron off (unaided) and Micron on (aided), both with image guidance. Preliminary results show that Micron significantly reduces the mean position error and the mean duration of time spent in specified dangerous zones. PMID:23366167

  9. Tremors and Klinefelter's Syndrome

    Directory of Open Access Journals (Sweden)

    Marcie L. Rabin

    2015-06-01

    Full Text Available Background: Klinefelter’s syndrome (KS has been associated with tremor, but reports on tremor phenomenology and treatment are limited. Case Reports: Patient 1 is a 17‐year‐old male with a dystonic tremor treated with deep brain stimulation (DBS. Patient 2 is a 57‐year‐old male with a predominant left hand resting tremor and dystonic features. Discussion: Our cases suggest that the tremor in patients with KS may be dystonic in nature. Patient 1 is also the third reported case of successful treatment with DBS. These cases have implications for elucidating the underlying neurobiological mechanism of tremor and identifying treatment options.

  10. 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...

  11. 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.

  12. 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

    2017-03-01

    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

  13. Treatment of Essential Tremor

    Science.gov (United States)

    ... for PATIENTS and their FAMILIES TREATMENT OF ESSENTIAL TREMOR This fact sheet is provided to help you understand which therapies help treat essential tremor. Neurologists from the American Academy of Neurology are ...

  14. San Andreas tremor cascades define deep fault zone complexity

    Science.gov (United States)

    Shelly, David R.

    2015-01-01

    Weak seismic vibrations - tectonic tremor - can be used to delineate some plate boundary faults. Tremor on the deep San Andreas Fault, located at the boundary between the Pacific and North American plates, is thought to be a passive indicator of slow fault slip. San Andreas Fault tremor migrates at up to 30 m s-1, but the processes regulating tremor migration are unclear. Here I use a 12-year catalogue of more than 850,000 low-frequency earthquakes to systematically analyse the high-speed migration of tremor along the San Andreas Fault. I find that tremor migrates most effectively through regions of greatest tremor production and does not propagate through regions with gaps in tremor production. I interpret the rapid tremor migration as a self-regulating cascade of seismic ruptures along the fault, which implies that tremor may be an active, rather than passive participant in the slip propagation. I also identify an isolated group of tremor sources that are offset eastwards beneath the San Andreas Fault, possibly indicative of the interface between the Monterey Microplate, a hypothesized remnant of the subducted Farallon Plate, and the North American Plate. These observations illustrate a possible link between the central San Andreas Fault and tremor-producing subduction zones.

  15. Rhythmic finger tapping reveals cerebellar dysfunction in essential tremor.

    Science.gov (United States)

    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

    2015-04-01

    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 cerebellar output in essential tremor during rhythmic finger tapping employing functional MRI. Thirty-one propranolol-sensitive essential tremor patients with upper limb tremor and 29 healthy controls were measured. T2*-weighted EPI sequences were acquired. The task consisted of alternating rest and finger tapping blocks. A whole-brain and region-of-interest analysis was performed, the latter focusing on the cerebellar cortex, dentate nucleus and inferior olive nucleus. Activations were also related to tremor severity. In patients, dentate activation correlated positively with tremor severity as measured by the tremor rating scale part A. Patients had reduced activation in widespread cerebellar cortical regions, and additionally in the inferior olive nucleus, and parietal and frontal cortex, compared to controls. The increase in dentate activation with tremor severity supports involvement of the dentate nucleus in essential tremor. Cortical and cerebellar changes during a motor timing task in essential tremor might point to widespread changes in cerebellar output in essential tremor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. In-Season Yield Prediction of Cabbage with a Hand-Held Active Canopy Sensor.

    Science.gov (United States)

    Ji, Rongting; Min, Ju; Wang, Yuan; Cheng, Hu; Zhang, Hailin; Shi, Weiming

    2017-10-08

    Efficient and precise yield prediction is critical to optimize cabbage yields and guide fertilizer application. A two-year field experiment was conducted to establish a yield prediction model for cabbage by using the Greenseeker hand-held optical sensor. Two cabbage cultivars (Jianbao and Pingbao) were used and Jianbao cultivar was grown for 2 consecutive seasons but Pingbao was only grown in the second season. Four chemical nitrogen application rates were implemented: 0, 80, 140, and 200 kg·N·ha -1 . Normalized difference vegetation index (NDVI) was collected 20, 50, 70, 80, 90, 100, 110, 120, 130, and 140 days after transplanting (DAT). Pearson correlation analysis and regression analysis were performed to identify the relationship between the NDVI measurements and harvested yields of cabbage. NDVI measurements obtained at 110 DAT were significantly correlated to yield and explained 87-89% and 75-82% of the cabbage yield variation of Jianbao cultivar over the two-year experiment and 77-81% of the yield variability of Pingbao cultivar. Adjusting the yield prediction models with CGDD (cumulative growing degree days) could make remarkable improvement to the accuracy of the prediction model and increase the determination coefficient to 0.82, while the modification with DFP (days from transplanting when GDD > 0) values did not. The integrated exponential yield prediction equation was better than linear or quadratic functions and could accurately make in-season estimation of cabbage yields with different cultivars between years.

  17. Lessons from (triggered) tremor

    Science.gov (United States)

    Gomberg, Joan

    2010-01-01

    I test a “clock-advance” model that implies triggered tremor is ambient tremor that occurs at a sped-up rate as a result of loading from passing seismic waves. This proposed model predicts that triggering probability is proportional to the product of the ambient tremor rate and a function describing the efficacy of the triggering wave to initiate a tremor event. Using data mostly from Cascadia, I have compared qualitatively a suite of teleseismic waves that did and did not trigger tremor with ambient tremor rates. Many of the observations are consistent with the model if the efficacy of the triggering wave depends on wave amplitude. One triggered tremor observation clearly violates the clock-advance model. The model prediction that larger triggering waves result in larger triggered tremor signals also appears inconsistent with the measurements. I conclude that the tremor source process is a more complex system than that described by the clock-advance model predictions tested. Results of this and previous studies also demonstrate that (1) conditions suitable for tremor generation exist in many tectonic environments, but, within each, only occur at particular spots whose locations change with time; (2) any fluid flow must be restricted to less than a meter; (3) the degree to which delayed failure and secondary triggering occurs is likely insignificant; and 4) both shear and dilatational deformations may trigger tremor. Triggered and ambient tremor rates correlate more strongly with stress than stressing rate, suggesting tremor sources result from time-dependent weakening processes rather than simple Coulomb failure.

  18. Quantitative methods for evaluating the efficacy of thalamic deep brain stimulation in patients with essential tremor.

    Science.gov (United States)

    Wastensson, Gunilla; Holmberg, Björn; Johnels, Bo; Barregard, Lars

    2013-01-01

    Deep brain stimulation (DBS) of the thalamus is a safe and efficient method for treatment of disabling tremor in patient with essential tremor (ET). However, successful tremor suppression after surgery requires careful selection of stimulus parameters. Our aim was to examine the possible use of certain quantitative methods for evaluating the efficacy of thalamic DBS in ET patients in clinical practice, and to compare these methods with traditional clinical tests. We examined 22 patients using the Essential Tremor Rating Scale (ETRS) and quantitative assessment of tremor with the stimulator both activated and deactivated. We used an accelerometer (CATSYS tremor Pen) for quantitative measurement of postural tremor, and a eurythmokinesimeter (EKM) to evaluate kinetic tremor in a rapid pointing task. The efficacy of DBS on tremor suppression was prominent irrespective of the method used. The agreement between clinical rating of postural tremor and tremor intensity as measured by the CATSYS tremor pen was relatively high (rs = 0.74). The agreement between kinetic tremor as assessed by the ETRS and the main outcome variable from the EKM test was low (rs = 0.34). The lack of agreement indicates that the EKM test is not comparable with the clinical test. Quantitative methods, such as the CATSYS tremor pen, could be a useful complement to clinical tremor assessment in evaluating the efficacy of DBS in clinical practice. Future studies should evaluate the precision of these methods and long-term impact on tremor suppression, activities of daily living (ADL) function and quality of life.

  19. Essential Tremor Is More Than a Tremor

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    Full Text Available ... About the IETF Volunteer For Healthcare Providers Giving Options Donate Prev Next IETF > About Essential Tremor > Video ... About the IETF Volunteer For Healthcare Providers Giving Options Donate Privacy Policy Contact Us Send to Email ...

  20. Essential Tremor Is More Than a Tremor

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    Full Text Available ... living with ET. It goes beyond diagnosis and treatments, to explore the emotional and psychosocial aspects of ... FDA Clearance for Cala ONE Wrist Device Neuromodulation Therapy Gives Relief From Hand Tremor IETF Accepting Proposals ...

  1. Essential Tremor Is More Than a Tremor

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    Full Text Available ... 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 ...

  2. 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 ... IETF Volunteer For Healthcare Providers Giving Options Donate Privacy Policy Contact Us Send to Email Address Your ...

  3. Essential Tremor Is More Than a Tremor

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  4. Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

    OpenAIRE

    Albanese, Alberto; Sorbo, Francesca Del

    2016-01-01

    Background: Dystonia and tremor share many commonalities. Isolated tremor is part of the phenomenological spectrum of isolated dystonia and of essential tremor. The occurrence of subtle features of dystonia may allow one to differentiate dystonic tremor from essential tremor. Diagnostic uncertainty is enhanced when no features of dystonia are found in patients with a tremor syndrome, raising the question whether the observed phenomenology is an incomplete form of dystonia. Methods: Known form...

  5. Genetics Home Reference: essential tremor

    Science.gov (United States)

    ... Facebook Twitter Home Health Conditions Essential tremor Essential tremor Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Essential tremor is a movement disorder that causes involuntary, rhythmic ...

  6. Task-related activity in sensorimotor cortex in Parkinson’s disease and essential tremor: changes in beta and gamma bands

    Directory of Open Access Journals (Sweden)

    Nathan C Rowland

    2015-09-01

    Full Text Available In Parkinson’s disease patients in the OFF medication state, basal ganglia local field potentials exhibit changes in beta and gamma oscillations that correlate with reduced voluntary movement, manifested as rigidity and akinesia. However, magnetoencephalography and low-resolution electrocorticography (ECoG studies in Parkinson’s patients suggest that changes in sensorimotor cortical oscillations differ from those of the basal ganglia. To more clearly define the role of sensorimotor cortex oscillatory activity in Parkinson’s, we performed intraoperative, high-resolution (4 mm spacing ECoG recordings in 10 Parkinson’s patients (2 females, ages 47-72 undergoing deep brain stimulation (DBS lead placement in the awake, OFF medication state. We analyzed ECoG potentials during a computer-controlled reaching task designed to separate movement preparation from movement execution and compared findings to similar invasive recordings in eight patients with essential tremor (3 females, ages 59-78, a condition not associated with rigidity or akinesia. We show that 1 cortical beta spectral power at rest does not differ between Parkinson’s and essential tremor patients (p = 0.85, 2 early motor preparation in Parkinson’s patients in the OFF medication state is associated with a larger beta desynchronization compared to patients with essential tremor (p = 0.0061, and 3 cortical broadband gamma power is elevated in Parkinson’s patients compared to essential tremor patients during both rest and task recordings (p = 0.004. Our findings suggest an oscillatory profile in sensorimotor cortex of Parkinson’s patients that, in contrast to the basal ganglia, may act to promote movement to oppose the anti-kinetic bias of the dopamine-depleted state.

  7. Distinguishing the Central Drive to Tremor in Parkinson's Disease and Essential Tremor

    Science.gov (United States)

    Brittain, John-Stuart; Cagnan, Hayriye; Mehta, Arpan R.; Saifee, Tabish A.; Edwards, Mark J.

    2015-01-01

    Parkinson's disease (PD) and essential tremor (ET) are the two most common movement disorders. Both have been associated with similar patterns of network activation leading to the suggestion that they may result from similar network dysfunction, specifically involving the cerebellum. Here, we demonstrate that parkinsonian tremors and ETs result from distinct patterns of interactions between neural oscillators. These patterns are reflected in the tremors' derived frequency tolerance, a novel measure readily attainable from bedside accelerometry. Frequency tolerance characterizes the temporal evolution of tremor by quantifying the range of frequencies over which the tremor may be considered stable. We found that patients with PD (N = 24) and ET (N = 21) were separable based on their frequency tolerance, with PD associated with a broad range of stable frequencies whereas ET displayed characteristics consistent with a more finely tuned oscillatory drive. Furthermore, tremor was selectively entrained by transcranial alternating current stimulation applied over cerebellum. Narrow frequency tolerances predicted stronger entrainment of tremor by stimulation, providing good evidence that the cerebellum plays an important role in pacing those tremors. The different patterns of frequency tolerance could be captured with a simple model based on a broadly coupled set of neural oscillators for PD, but a more finely tuned set of oscillators in ET. Together, these results reveal a potential organizational principle of the human motor system, whose disruption in PD and ET dictates how patients respond to empirical, and potentially therapeutic, interventions that interact with their underlying pathophysiology. PMID:25589772

  8. Stereotactic neurosurgery for tremor

    NARCIS (Netherlands)

    Speelman, Johannes D.; Schuurman, Richard; de Bie, Rob M. A.; Esselink, Rianne A. J.; Bosch, D. Andries

    2002-01-01

    The role of the motor thalamus as surgical target in stereotactic neurosurgery for different kinds of tremor is discussed. For tremor in Parkinson's disease. the subthalamic nucleus becomes more and more often the surgical target, because this target also gives relief of other and more

  9. Approach to a tremor patient

    Science.gov (United States)

    Sharma, Soumya; Pandey, Sanjay

    2016-01-01

    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. PMID:27994349

  10. Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

    Directory of Open Access Journals (Sweden)

    Alberto Albanese

    2016-04-01

    Full Text Available Background: Dystonia and tremor share many commonalities. Isolated tremor is part of the phenomenological spectrum of isolated dystonia and of essential tremor. The occurrence of subtle features of dystonia may allow one to differentiate dystonic tremor from essential tremor. Diagnostic uncertainty is enhanced when no features of dystonia are found in patients with a tremor syndrome, raising the question whether the observed phenomenology is an incomplete form of dystonia. Methods: Known forms of syndromes with isolated tremor are reviewed. Diagnostic uncertainties between tremor and dystonia are put into perspective. Results: The following isolated tremor syndromes are reviewed: essential tremor, head tremor, voice tremor, jaw tremor, and upper-limb tremor. Their varied phenomenology is analyzed and appraised in the light of a possible relationship with dystonia. Discussion: Clinicians making a diagnosis of isolated tremor should remain vigilant for the detection of features of dystonia. This is in keeping with the recent view that isolated tremor may be an incomplete phenomenology of dystonia.

  11. Dystonia and Tremor: The Clinical Syndromes with Isolated Tremor

    Science.gov (United States)

    Albanese, Alberto; Sorbo, Francesca Del

    2016-01-01

    Background Dystonia and tremor share many commonalities. Isolated tremor is part of the phenomenological spectrum of isolated dystonia and of essential tremor. The occurrence of subtle features of dystonia may allow one to differentiate dystonic tremor from essential tremor. Diagnostic uncertainty is enhanced when no features of dystonia are found in patients with a tremor syndrome, raising the question whether the observed phenomenology is an incomplete form of dystonia. Methods Known forms of syndromes with isolated tremor are reviewed. Diagnostic uncertainties between tremor and dystonia are put into perspective. Results The following isolated tremor syndromes are reviewed: essential tremor, head tremor, voice tremor, jaw tremor, and upper-limb tremor. Their varied phenomenology is analyzed and appraised in the light of a possible relationship with dystonia. Discussion Clinicians making a diagnosis of isolated tremor should remain vigilant for the detection of features of dystonia. This is in keeping with the recent view that isolated tremor may be an incomplete phenomenology of dystonia. PMID:27152246

  12. Consensus Statement on the classification of tremors. from the task force on tremor of the International Parkinson and Movement Disorder Society.

    Science.gov (United States)

    Bhatia, Kailash P; Bain, Peter; Bajaj, Nin; Elble, Rodger J; Hallett, Mark; Louis, Elan D; Raethjen, Jan; Stamelou, Maria; Testa, Claudia M; Deuschl, Guenther

    2018-01-01

    Consensus criteria for classifying tremor disorders were published by the International Parkinson and Movement Disorder Society in 1998. Subsequent advances with regard to essential tremor, tremor associated with dystonia, and other monosymptomatic and indeterminate tremors make a significant revision necessary. Convene an international panel of experienced investigators to review the definition and classification of tremor. Computerized MEDLINE searches in January 2013 and 2015 were conducted using a combination of text words and MeSH terms: "tremor", "tremor disorders", "essential tremor", "dystonic tremor", and "classification" limited to human studies. Agreement was obtained using consensus development methodology during four in-person meetings, two teleconferences, and numerous manuscript reviews. Tremor is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: Axis 1-clinical characteristics, including historical features (age at onset, family history, and temporal evolution), tremor characteristics (body distribution, activation condition), associated signs (systemic, neurological), and laboratory tests (electrophysiology, imaging); and Axis 2-etiology (acquired, genetic, or idiopathic). Tremor syndromes, consisting of either isolated tremor or tremor combined with other clinical features, are defined within Axis 1. This classification scheme retains the currently accepted tremor syndromes, including essential tremor, and provides a framework for defining new syndromes. This approach should be particularly useful in elucidating isolated tremor syndromes and syndromes consisting of tremor and other signs of uncertain significance. Consistently defined Axis 1 syndromes are needed to facilitate the elucidation of specific etiologies in Axis 2. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

  13. Cataloging tremor at Kilauea Volcano, Hawaii

    Science.gov (United States)

    Thelen, W. A.; Wech, A.

    2013-12-01

    Tremor is a ubiquitous seismic feature on Kilauea volcano, which emanates from at least three distinct sources. At depth, intermittent tremor and earthquakes thought to be associated with the underlying plumbing system of Kilauea (Aki and Koyanagi, 1981) occurs approximately 40 km below and 40 km SW of the summit. At the summit of the volcano, nearly continuous tremor is recorded close to a persistently degassing lava lake, which has been present since 2008. Much of this tremor is correlated with spattering at the lake surface, but tremor also occurs in the absence of spattering, and was observed at the summit of the volcano prior to the appearance of the lava lake, predominately in association with inflation/deflation events. The third known source of tremor is in the area of Pu`u `O`o, a vent that has been active since 1983. The exact source location and depth is poorly constrained for each of these sources. Consistently tracking the occurrence and location of tremor in these areas through time will improve our understanding of the plumbing geometry beneath Kilauea volcano and help identify precursory patterns in tremor leading to changes in eruptive activity. The continuous and emergent nature of tremor precludes the use of traditional earthquake techniques for automatic detection and location of seismicity. We implement the method of Wech and Creager (2008) to both detect and localize tremor seismicity in the three regions described above. The technique uses an envelope cross-correlation method in 5-minute windows that maximizes tremor signal coherency among seismic stations. The catalog is currently being built in near-realtime, with plans to extend the analysis to the past as time and continuous data availability permits. This automated detection and localization method has relatively poor depth constraints due to the construction of the envelope function. Nevertheless, the epicenters distinguish activity among the different source regions and serve as

  14. Is Slow Slip a Cause or a Result of Tremor?

    Science.gov (United States)

    Luo, Y.; Ampuero, J. P.

    2017-12-01

    of tremor activity. We also find that, despite important interactions between asperities, tremor activity rates are proportional to the underlying aseismic slip rate, supporting an approach to estimate SSE properties with high spatial-temporal resolutions via tremor activity.

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

    Science.gov (United States)

    Hallett, Mark; Deuschl, Günther; Toni, Ivan; Bloem, Bastiaan 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 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. PMID:22382359

  16. Different patterns of spontaneous brain activity between tremor-dominant and postural instability/gait difficulty subtypes of Parkinson's disease: a resting-state fMRI study.

    Science.gov (United States)

    Chen, Hui-Min; Wang, Zhi-Jiang; Fang, Jin-Ping; Gao, Li-Yan; Ma, Ling-Yan; Wu, Tao; Hou, Ya-Nan; Zhang, Jia-Rong; Feng, Tao

    2015-10-01

    Postural instability/gait difficulty (PIGD) and tremor-dominant (TD) subtypes of Parkinson's disease (PD) show different clinical manifestations; however, their underlying neural substrates remain incompletely understood. This study aimed at investigating the subtype-specific patterns of spontaneous brain activity in PD. Thirty-one patients with PD (12 TD/19 PIGD) and 22 healthy gender- and age-matched controls were recruited. Resting-state functional magnetic resonance imaging data were collected, and amplitude of low-frequency fluctuations (ALFF) was measured. Voxelwise one-way analysis of covariance and post hoc analyses of ALFF were performed among the three groups, with age and gender as covariates (levodopa daily dosage and gray matter volume as additional covariates for validation analysis). Correlations of clinical variables (e.g., disease duration and PIGD/tremor subscale score) with ALFF values were examined. Compared with controls, patients with TD exhibited higher ALFF in the right cerebellar posterior lobe and patients with PIGD exhibited lower ALFF in the bilateral putamen and cerebellar posterior lobe, and higher values primarily in several cortical areas including the inferior and superior temporal gyrus, superior frontal, and parietal gyrus. Compared with patients with PIGD, patients with TD had higher ALFF in the bilateral putamen and the cerebellar posterior lobe, as well as lower ALFF in the bilateral temporal gyrus and the left superior parietal lobule. In all patients, ALFF in the bilateral cerebellar posterior lobe positively correlated with tremor score and ALFF in the bilateral putamen negatively correlated with PIGD score. Different patterns of spontaneous neural activity in the cerebellum and putamen may underlie the neural substrate of PD motor subtypes. © 2015 John Wiley & Sons Ltd.

  17. Tremor - self-care

    Science.gov (United States)

    ... in your day-to-day: Buy clothes with Velcro fasteners instead of buttons or hooks. Cook or ... your tremor. Some of these medicines have side effects. Tell your provider if you have these symptoms ...

  18. How to treat tremor.

    Science.gov (United States)

    Rektor, Ivan; Rektorová, Irena; Suchý, Václav

    2004-05-01

    This paper presents an example of 18(th) century medical thinking. The author, Dr Georg Ernst Stahl (1659-1734) was the founder of the phlogiston theory in the field of chemistry, a medical professor, and a court physician in Saxony and Prussia. His description includes a definition of tremor, the internal and external causes of tremor, the types of tremor, the diagnostic and prognostic signs, and the treatment. From a present (contemporary) point of view, some compounds that were then used in treatment may have had a limited therapeutic effect on some kinds of tremor. Protopin has an anticholinergic and GABA-ergic effect, and rhoeadin (tetrahydrobenzazepin) may have had an effect similar to that of neuroleptics. Nevertheless, it is not clear whether the recommended quantity of these compounds was sufficient for a clinical effect. Most of the prescribed drugs could only have had a placebo effect.

  19. Serotonergic modulation of nicotine-induced kinetic tremor in mice

    Directory of Open Access Journals (Sweden)

    Naofumi Kunisawa

    2017-06-01

    Full Text Available We previously demonstrated that nicotine elicited kinetic tremor by elevating the neural activity of the inferior olive via α7 nicotinic acetylcholine (nACh receptors. Since α7 nACh receptors reportedly facilitate synaptic monoamine release, we explored the role of 5-HT receptors in induction and/or modulation of nicotine tremor. Treatment of mice with nicotine induced kinetic tremor that normally appeared during movement. The 5-HT1A agonist, 8-hydroxydipropylaminotetraline (8-OH-DPAT, significantly enhanced nicotine-induced tremor and the action of 8-OH-DPAT was antagonized by WAY-100135 (5-HT1A antagonist. In addition, the cerebral 5-HT depletion by repeated treatment with p-chlorophenylalanine did not reduce, but rather potentiated the facilitatory effects of 8-OH-DPAT. In contrast, the 5-HT2 agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI, significantly attenuated nicotine tremor, which was antagonized by ritanserin (5-HT2 antagonist. The 5-HT3 agonist SR-57227 did not affect nicotine-induced tremor. Furthermore, when testing the direct actions of 5-HT antagonists, nicotine tremor was inhibited by WAY-100135, but was unaffected by ritanserin, ondansetron (5-HT3 antagonist or SB-258585 (5-HT6 antagonist. These results suggest that postsynaptic 5-HT1A receptors are involved in induction of nicotine tremor mediated by α7 nACh receptors. In addition, 5-HT2 receptors have an inhibitory modulatory role in induction of nicotine tremor.

  20. Botulinum Toxin in Management of Limb Tremor

    Directory of Open Access Journals (Sweden)

    Elina Zakin

    2017-11-01

    Full Text Available Essential tremor is characterized by persistent, usually bilateral and symmetric, postural or kinetic activation of agonist and antagonist muscles involving either the distal or proximal upper extremity. Quality of life is often affected and one’s ability to perform daily tasks becomes impaired. Oral therapies, including propranolol and primidone, can be effective in the management of essential tremor, although adverse effects can limit their use and about 50% of individuals lack response to oral pharmacotherapy. Locally administered botulinum toxin injection has become increasingly useful in the management of essential tremor. Targeting of select muscles with botulinum toxin is an area of active research, and muscle selection has important implications for toxin dosing and functional outcomes. The use of anatomical landmarks with palpation, EMG guidance, electrical stimulation, and ultrasound has been studied as a technique for muscle localization in toxin injection. Earlier studies implemented a standard protocol for the injection of (predominantly wrist flexors and extensors using palpation and EMG guidance. Targeting of muscles by selection of specific activators of tremor (tailored to each patient using kinematic analysis might allow for improvement in efficacy, including functional outcomes. It is this individualized muscle selection and toxin dosing (requiring injection within various sites of a single muscle that has allowed for success in the management of tremors.

  1. Coherence analysis differentiates between cortical myoclonic tremor and essential tremor

    NARCIS (Netherlands)

    van Rootselaar, AF; Maurits, NM; Koelman, JHTM; van der Hoeven, JH; Bour, LJ; Leenders, KL; Brown, P; Tijssen, MAJ

    Familial cortical myoclonic tremor with epilepsy (FCMTE) is characterized by a distal kinetic tremor, infrequent epileptic attacks, and autosomal dominant inheritance. The tremor is thought to originate from the motor cortex. In our patient group, a premovement cortical spike Could not be

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

    NARCIS (Netherlands)

    Dirkx, M.F.M.; Ouden, H.E.M. den; Aarts, E.; Timmer, M.H.M.; Bloem, B.R.; Toni, I.; Helmich, R.C.G.

    2017-01-01

    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

  3. Towards Vision-Based Control of a Handheld Micromanipulator for Retinal Cannulation in an Eyeball Phantom

    Science.gov (United States)

    Becker, Brian C.; Yang, Sungwook; MacLachlan, Robert A.; Riviere, Cameron N.

    2012-01-01

    Injecting clot-busting drugs such as t-PA into tiny vessels thinner than a human hair in the eye is a challenging procedure, especially since the vessels lie directly on top of the delicate and easily damaged retina. Various robotic aids have been proposed with the goal of increasing safety by removing tremor and increasing precision with motion scaling. We have developed a fully handheld micromanipulator, Micron, that has demonstrated reduced tremor when cannulating porcine retinal veins in an “open sky” scenario. In this paper, we present work towards handheld robotic cannulation with the goal of vision-based virtual fixtures guiding the tip of the cannula to the vessel. Using a realistic eyeball phantom, we address sclerotomy constraints, eye movement, and non-planar retina. Preliminary results indicate a handheld micromanipulator aided by visual control is a promising solution to retinal vessel occlusion. PMID:24649479

  4. ITSY Handheld Software Radio

    National Research Council Canada - National Science Library

    Bose, Vanu

    2001-01-01

    .... A handheld software radio platform would enable the construction of devices that could inter-operate with multiple legacy systems, download new waveforms and be used to construct adhoc networks...

  5. Disorders of balance and gait in essential tremor are associated with midline tremor and age.

    Science.gov (United States)

    Hoskovcová, Martina; Ulmanová, Olga; Sprdlík, Otakar; Sieger, Tomáš; Nováková, Jana; Jech, Robert; Růžička, Evžen

    2013-02-01

    Disorders of balance and gait have been observed in patients with essential tremor (ET), but their association with tremor severity remains unclear. This study aimed to evaluate postural instability and gait changes in ET patients and to investigate their relationship to tremor characteristics with regard to cerebellar dysfunction as a possible common pathogenetic mechanism in ET. Thirty ET patients (8F, mean (SD) age 55.8 (17.8), range 19-81 years) and 25 normal controls (7F, 53.0 (17.7), 19-81) were tested with the scales of Activities-specific Balance Confidence (ABC), Fullerton Advanced Balance (FAB), and International Cooperative Ataxia Rating Scale (ICARS). Posturography and gait were assessed using a Footscan® system. Tremor was evaluated by the Fahn-Tolosa-Marin Tremor Rating Scale (TRS) and accelerometry in five upper limb positions. A mean (SD) TRS sum score of 27.0 (13.2) corresponded to mild to moderate tremor severity in most patients. In comparison with controls, ET subjects exhibited lower tandem gait velocity (0.21 vs. 0.26 m/s, P = 0.028), more missteps (0.57 vs. 0.12, P = 0.039), and increased postural sway in tandem stance (sway area 301.1 vs. 202.9 mm(2), P = 0.045). In normal gait, step width increased with the midline tremor subscore of TRS (Pearson r = 0.60, P = 0.046). Moreover, significant correlations were found between age and quantitative measures of normal and tandem gait in ET patients but not in controls. ABC, FAB, and ICARS scores did not significantly differ between patients and controls. In conclusion, gait and balance alterations in ET patients occur even without subjective complaints. Their relationship with midline tremor and dependence on age suggest a connection with cerebellar dysfunction.

  6. Global search of triggered non-volcanic tremor

    Science.gov (United States)

    Chao, Tzu-Kai Kevin

    chapter focuses on a systematic comparison of triggered tremor around the Calaveras Fault (CF) in northern California (NC), the Parkfield-Cholame section of the San Andreas Fault (SAF) in central California (CC), and the San Jacinto Fault (SJF) in southern California (SC). Out of 42 large (Mw ≥7.5) earthquakes between 2001 and 2010, only the 2002 Mw 7.9 Denali fault earthquake triggered clear tremor in NC and SC. In comparison, abundant triggered and ambient tremor has been observed in CC. Further analysis reveal that the lack of triggered tremor observations in SC and NC is not simply a consequence of their different background noise levels as compared to CC, but rather reflects different background tremor rates in these regions. In the final chapter, I systematically search for triggered tremor following the 2011 Mw9.0 Tohoku-Oki earthquake in the regions where ambient or triggered tremor has been found before. The main purpose is to check whether triggered tremor is observed in regions when certain conditions (e.g., surface wave amplitudes) are met. Triggered tremor is observed in southwest Japan, Taiwan, the Aleutian Arc, south-central Alaska, northern Vancouver Island, the Parkfield-Cholame section of the SAF in CC and the SJF in SC, and the North Island of New Zealand. Such a widespread triggering of tremor is not too surprising because of the large amplitude surface waves (minimum peak value of ˜0.1 cm/s) and the associated dynamic stresses (at least ˜7-8 kPa), which is one of the most important factors in controlling the triggering threshold. The triggered tremor in different region is located close to or nearby the ambient tremor active area. In addition, the amplitudes of triggered tremor have positive correlations with the amplitudes of teleseismic surface waves among many regions. Moreover, both Love and Rayleigh waves participate in triggering tremor in different regions, and their triggering potential is somewhat controlled by the incident angles. In

  7. Seismic network based detection, classification and location of volcanic tremors

    Science.gov (United States)

    Nikolai, S.; Soubestre, J.; Seydoux, L.; de Rosny, J.; Droznin, D.; Droznina, S.; Senyukov, S.; Gordeev, E.

    2017-12-01

    Volcanic tremors constitute an important attribute of volcanic unrest in many volcanoes, and their detection and characterization is a challenging issue of volcano monitoring. The main goal of the present work is to develop a network-based method to automatically classify volcanic tremors, to locate their sources and to estimate the associated wave speed. The method is applied to four and a half years of seismic data continuously recorded by 19 permanent seismic stations in the vicinity of the Klyuchevskoy volcanic group (KVG) in Kamchatka (Russia), where five volcanoes were erupting during the considered time period. The method is based on the analysis of eigenvalues and eigenvectors of the daily array covariance matrix. As a first step, following Seydoux et al. (2016), most coherent signals corresponding to dominating tremor sources are detected based on the width of the covariance matrix eigenvalues distribution. With this approach, the volcanic tremors of the two volcanoes known as most active during the considered period, Klyuchevskoy and Tolbachik, are efficiently detected. As a next step, we consider the array covariance matrix's first eigenvectors computed every day. The main hypothesis of our analysis is that these eigenvectors represent the principal component of the daily seismic wavefield and, for days with tremor activity, characterize the dominant tremor sources. Those first eigenvectors can therefore be used as network-based fingerprints of tremor sources. A clustering process is developed to analyze this collection of first eigenvectors, using correlation coefficient as a measure of their similarity. Then, we locate tremor sources based on cross-correlations amplitudes. We characterize seven tremor sources associated with different periods of activity of four volcanoes: Tolbachik, Klyuchevskoy, Shiveluch, and Kizimen. The developed method does not require a priori knowledge, is fully automatic and the database of network-based tremor fingerprints

  8. Pyxis handheld polarimetric imager

    Science.gov (United States)

    Chenault, David B.; Pezzaniti, J. Larry; Vaden, Justin P.

    2016-05-01

    The instrumentation for measuring infrared polarization signatures has seen significant advancement over the last decade. Previous work has shown the value of polarimetric imagery for a variety of target detection scenarios including detection of manmade targets in clutter and detection of ground and maritime targets while recent work has shown improvements in contrast for aircraft detection and biometric markers. These data collection activities have generally used laboratory or prototype systems with limitations on the allowable amount of target motion or the sensor platform and usually require an attached computer for data acquisition and processing. Still, performance and sensitivity have been steadily getting better while size, weight, and power requirements have been getting smaller enabling polarimetric imaging for a greater or real world applications. In this paper, we describe Pyxis®, a microbolometer based imaging polarimeter that produces live polarimetric video of conventional, polarimetric, and fused image products. A polarization microgrid array integrated in the optical system captures all polarization states simultaneously and makes the system immune to motion artifacts of either the sensor or the scene. The system is battery operated, rugged, and weighs about a quarter pound, and can be helmet mounted or handheld. On board processing of polarization and fused image products enable the operator to see polarimetric signatures in real time. Both analog and digital outputs are possible with sensor control available through a tablet interface. A top level description of Pyxis® is given followed by performance characteristics and representative data.

  9. Tremor entities and their classification: an update.

    Science.gov (United States)

    Gövert, Felix; Deuschl, Günther

    2015-08-01

    This review focuses on important new findings in the field of tremor and illustrates the consequences for the current definition and classification of tremor. Since 1998 when the consensus criteria for tremor were proposed, new variants of tremors and new diagnostic methods were discovered that have changed particularly the concepts of essential tremor and dystonic tremor. Accumulating evidence exists that essential tremor is not a single entity rather different conditions that share the common symptom action tremor without other major abnormalities. Tremor is a common feature in patients with adult-onset focal dystonia and may involve several different body parts and forms of tremor. Recent advances, in particular, in the field of genetics, suggest that dystonic tremor may even be present without overt dystonia. Monosymptomatic asymmetric rest and postural tremor has been further delineated, and apart from tremor-dominant Parkinson's disease, there are several rare conditions including rest and action tremor with normal dopamine transporter imaging (scans without evidence of dopaminergic deficit) and essential tremor with tremor at rest. Increasing knowledge in the last decades changed the view on tremors and highlights several caveats in the current tremor classification. Given the ambiguous assignment between tremor phenomenology and tremor etiology, a more cautious definition of tremors on the basis of clinical assessment data is needed.

  10. 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.

    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

  11. Tremor Source Location at Okmok Volcano

    Science.gov (United States)

    Reyes, C. G.; McNutt, S. R.

    2007-12-01

    Initial results using an amplitude-based tremor location program have located several active tremor episodes under Cone A, a vent within Okmok volcano's 10 km caldera. Okmok is an andesite volcano occupying the north-eastern half of Umnak Island, in the Aleutian islands. Okmok is defined by a ~2000 y.b.p. caldera that contains multiple cinder cones. Cone A, the youngest of these, extruded lava in 1997 covering the caldera floor. Since April 2003, continuous seismic data have been recorded from eight vertical short-period stations (L4-C's) installed at distances from Cone A ranging from 2 km to 31 km. In 2004 four additional 3- component broadband stations were added, co-located with continuous GPS stations. InSAR and GPS measurements of post-eruption deformation show that Okmok experienced several periods of rapid inflation (Mann and Freymueller, 2002), from the center of the 10 km diameter caldera. While there are few locatable VT earthquakes, there has been nearly continuous low-level tremor with stronger amplitude bursts occurring at variable rates and durations. The character of occurrence remained relatively constant over the course of days to weeks until the signal ceased in mid 2005. Within any day, tremor behavior remains fairly consistent, with bursts closely resembling each other, suggesting a single main process or source location. The tremor is composed of irregular waves with a broad range of frequencies, though most energy resides between ~2 Hz and 6 Hz. Attempts to locate the tremor using traditional arrival time methods fail because the signal is emergent, with envelopes too ragged to correlate on time scales that hold much hope for a location. Instead, focus was shifted to the amplitude ratios at various stations. Candidates for the tremor source include the center of inflation and Cone A, 3 km to the south-west. For all dates on record, data were band pass filtered between 1 and 5 Hz, then evaluated in 20.48 second windows (N=2048, sampling rate

  12. 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.

  13. Essential Tremor: A Neurodegenerative Disease?

    Directory of Open Access Journals (Sweden)

    Julian Benito-Leon

    2014-07-01

    Full Text Available Background: Essential tremor (ET is one of the most common neurological disorders among adults, and is the most common of the many tremor disorders. It has classically been viewed as a benign monosymptomatic condition, yet over the past decade, a growing body of evidence indicates that ET is a progressive condition that is clinically heterogeneous, as it may be associated with a spectrum of clinical features, with both motor and non‐motor elements. In this review, I will describe the most significant emerging milestones in research which, when taken together, suggest that ET is a neurodegenerative condition.Methods: A PubMed search conducted in June 2014 crossing the terms “essential tremor” (ET and “neurodegenerative” yielded 122 entries, 20 of which included the term “neurodegenerative” in the article title. This was supplemented by articles in the author's files that pertained to this topic.Results/Discussion: There is an open and active dialogue in the medical community as to whether ET is a neurodegenerative disease, with considerable evidence in favor of this. Specifically, ET is a progressive disorder of aging associated with neuronal loss (reduction in Purkinje cells as well as other post‐mortem changes that occur in traditional neurodegenerative disorders. Along with this, advanced neuroimaging techniques are now demonstrating distinct structural changes, several of which are consistent with neuronal loss, in patients with ET. However, further longitudinal clinical and neuroimaging longitudinal studies to assess progression are required.

  14. 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.

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

    Science.gov (United States)

    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 better insight into tremor. Typically, routine clinical assessment of accelerometry and electromyography data involves visual inspection by clinicians and occasionally computational analysis to obtain objective characteristics of tremor. However, for some tremor disorders these characteristics may be different during daily activity. This variability in presentation between the clinic and daily life makes a differential diagnosis more difficult. A long-term recording of tremor by accelerometry and/or electromyography in the home environment could help to give a better insight into the tremor disorder. However, an evaluation of such recordings using routine clinical standards would take too much time. We evaluated a range of techniques that automatically detect tremor segments in accelerometer data, as accelerometer data is more easily obtained in the home environment than electromyography data. Time can be saved if clinicians only have to evaluate the tremor characteristics of segments that have been automatically detected in longer daily activity recordings. We tested four non-parametric methods and five parametric methods on clinical accelerometer data from 14 patients with different tremor disorders. The consensus between two clinicians regarding the presence or absence of tremor on 3943 segments of accelerometer data was employed as reference. The nine methods were tested against this reference to identify their optimal parameters. Non-parametric methods generally performed better than parametric methods on our dataset when optimal parameters were used. However, one parametric method, employing the high frequency content of the tremor bandwidth under consideration

  16. Dystonia Associated with Idiopathic Slow Orthostatic Tremor

    Directory of Open Access Journals (Sweden)

    Christopher Kobylecki

    2016-02-01

    Full Text Available Background: We aimed to characterize the clinical and electrophysiological features of patients with slow orthostatic tremor.Case Report: The clinical and neurophysiological data of patients referred for lower limb tremor on standing were reviewed. Patients with symptomatic or primary orthostatic tremor were excluded. Eight patients were identified with idiopathic slow 4–8 Hz orthostatic tremor, which was associated with tremor and dystonia in cervical and upper limb musculature. Coherence analysis in two patients showed findings different to those seen in primary orthostatic tremor.Discussion: Slow orthostatic tremor may be associated with dystonia and dystonic tremor.

  17. Serotonergic modulation of nicotine-induced kinetic tremor in mice.

    Science.gov (United States)

    Kunisawa, Naofumi; Iha, Higor A; Nomura, Yuji; Onishi, Misaki; Matsubara, Nami; Shimizu, Saki; Ohno, Yukihiro

    2017-06-01

    We previously demonstrated that nicotine elicited kinetic tremor by elevating the neural activity of the inferior olive via α7 nicotinic acetylcholine (nACh) receptors. Since α7 nACh receptors reportedly facilitate synaptic monoamine release, we explored the role of 5-HT receptors in induction and/or modulation of nicotine tremor. Treatment of mice with nicotine induced kinetic tremor that normally appeared during movement. The 5-HT 1A agonist, 8-hydroxydipropylaminotetraline (8-OH-DPAT), significantly enhanced nicotine-induced tremor and the action of 8-OH-DPAT was antagonized by WAY-100135 (5-HT 1A antagonist). In addition, the cerebral 5-HT depletion by repeated treatment with p-chlorophenylalanine did not reduce, but rather potentiated the facilitatory effects of 8-OH-DPAT. In contrast, the 5-HT 2 agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), significantly attenuated nicotine tremor, which was antagonized by ritanserin (5-HT 2 antagonist). The 5-HT 3 agonist SR-57227 did not affect nicotine-induced tremor. Furthermore, when testing the direct actions of 5-HT antagonists, nicotine tremor was inhibited by WAY-100135, but was unaffected by ritanserin, ondansetron (5-HT 3 antagonist) or SB-258585 (5-HT 6 antagonist). These results suggest that postsynaptic 5-HT 1A receptors are involved in induction of nicotine tremor mediated by α7 nACh receptors. In addition, 5-HT 2 receptors have an inhibitory modulatory role in induction of nicotine tremor. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  18. Tremor in the Elderly: Essential and Aging-Related Tremor

    Science.gov (United States)

    Deuschl, Günthe; Petersen, Inge; Lorenz, Delia; Christensen, Kaare

    2016-01-01

    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 their tremor severity, and classical aging phenotypes were assessed. A subgroup of 276 individuals fulfilling either screening criteria for ET or being controls were personally assessed. Medications and mortality data are available. The spiral score increased with age. The spiral score correlated with tremor severity. For the whole cohort, mortality was significantly correlated with the spiral score, and higher spiral scores were associated with lower physical and cognitive functioning. Multivariate analysis identified higher spiral scores as an independent risk factor for mortality. In contrast, the ET 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 and mortality than controls and ET, we propose to label it ‘aging-related tremor’ (ART). This tremor starts later in life and is accompanied by subtle signs of aging both cognitively and physically. More detailed clinical features and pathogenesis warrant further assessment. PMID:26095699

  19. Surgery for Dystonia and Tremor.

    Science.gov (United States)

    Crowell, Jason L; Shah, Binit B

    2016-03-01

    Surgical procedures for dystonia and tremor have evolved over the past few decades, and our understanding of risk, benefit, and predictive factors has increased substantially in that time. Deep brain stimulation (DBS) is the most utilized surgical treatment for dystonia and tremor, though lesioning remains an effective option in appropriate patients. Dystonic syndromes that have shown a substantial reduction in severity secondary to DBS are isolated dystonia, including generalized, cervical, and segmental, as well as acquired dystonia such as tardive dystonia. Essential tremor is quite amenable to DBS, though the response of other forms of postural and kinetic tremor is not nearly as robust or consistent based on available evidence. Regarding targeting, DBS lead placement in the globus pallidus internus has shown marked efficacy in dystonia reduction. The subthalamic nucleus is an emerging target, and increasing evidence suggests that this may be a viable target in dystonia as well. The ventralis intermedius nucleus of the thalamus is the preferred target for essential tremor, though targeting the subthalamic zone/caudal zona incerta has shown promise and may emerge as another option in essential tremor and possibly other tremor disorders. In the carefully selected patient, DBS and lesioning procedures are relatively safe and effective for the management of dystonia and tremor.

  20. [Clinical subtypes of essential tremor and their electrophysiological and pharmacological differences].

    Science.gov (United States)

    Koguchi, Y; Nakajima, M; Kawamura, M; Hirayama, K

    1995-02-01

    We divided 19 patients with essential tremor into two subtypes according to clinical characteristics of the tremor. Ten patients had pure postural tremor distributed in the hand(s), head, and face (group A). Nine patients had tremor extending to the voice or leg(s), associated with resting tremor and/or hyperkinesie volitionnelle of the hand(s) (group B). Their ages, the age of onset, and the duration of illness were not different between the two groups. Electrophysiologically, the tremor of group A patients had higher frequencies than that of group B patients, and had synchronized activities for antagonistic muscles. Four of group B patients had reciprocal antagonistic activities of the tremor. Inactive phase of tremor induced by an electrically-evoked muscle twitch was invariably within the range of the physiological silent period for group A patients, and prolonged beyond the range for four of group B patients. Pharmacologically, 78% of group A patients responded well to beta-blocker, which was effective for 25% of group B patients. Sixty per cent of beta-blocker-resistant group B patients responded well to phenobarbital. In conclusion, a peripheral mechanism, presumably beta-adrenergic drive, is important for the tremor in group A patients, while central pathogenic mechanisms are more important for the tremor of group B patients.

  1. Is tremor related to celiac disease?

    Science.gov (United States)

    Ameghino, Lucia; Rossi, Malco Damian; Cerquetti, Daniel; Merello, Marcelo

    2017-06-14

    Neurological features in celiac disease (CD) are not rare (5%-36%), but tremor is scarcely described. Subjects with CD and healthy controls completed an online survey using WHIGET tremor rating scale. One thousand five hundred and twelve subjects completed the survey, finally 674 CD patients and 290 healthy subjects were included. A higher prevalence of tremor in CD patients was observed in comparison to controls (28% vs 14%, P tremor in CD patients with and without tremor was 25% and 20% ( P = 0.2), while in the control group it was 41% and 10% ( P tremor showed a higher frequency of family history of tremor when compared to CD patients with tremor (41.5% vs 24.6%, P = 0.03). The results suggested that tremor in CD might be more frequent and possibly related to the disease itself and not due to associated essential tremor.

  2. Treatment of essential tremor with arotinolol.

    Science.gov (United States)

    Kuroda, Y; Kakigi, R; Shibasaki, H

    1988-04-01

    We investigated the effect of arotinolol, a new peripherally acting beta-adrenergic blocker, in 15 patients with essential tremor. The patients received 30 mg per day of arotinolol for 8 weeks. Accelerometer readings showed a significant reduction in amplitude of postural tremor after treatment. Action tremor also improved to essentially the same degree as postural tremor. The present findings support the view that the therapeutic effect of beta-blockers in essential tremor is mediated by peripheral beta-adrenergic receptors.

  3. Intermittent cortical involvement in the preservation of tremor in essential tremor

    NARCIS (Netherlands)

    Sharifi, Sarvi; Luft, Frauke; Verhagen, Rens; Heida, Tjitske; Speelman, Johannes D.; Bour, Lo J.; van Rootselaar, Anne-Fleur

    2017-01-01

    Cortical involvement in essential tremor, an involuntary action tremor supposedly of subcortical origin, is uncertain. Conflicting results of corticomuscular coherence studies in essential tremor suggest an intermittent corticomuscular coupling. On the basis of the literature, we hypothesized that

  4. 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.

  5. Tremor cells in the human thalamus: differences among neurological disorders.

    Science.gov (United States)

    Brodkey, Jason A; Tasker, Ronald R; Hamani, Clement; McAndrews, Mary Pat; Dostrovsky, Jonathan O; Lozano, Andres M

    2004-07-01

    Thalamic neurons firing at frequencies synchronous with tremor are thought to play a critical role in the generation and maintenance of tremor. The authors studied the incidence and locations of neurons with tremor-related activity (TRA) in the thalamus of patients with varied pathological conditions-including Parkinson disease (PD), essential tremor (ET), multiple sclerosis (MS), and cerebellar disorders--to determine whether known differences in the effectiveness of thalamic stereotactic procedures for these tremors could be correlated to differences in the incidence or locations of TRA cells. Seventy-five operations were performed in 61 patients during which 686 TRA cells were recorded from 440 microelectrode trajectories in the thalamus. The locations of the TRA cells in relation to electrophysiologically defined thalamic nuclei and the commissural coordinates were compared among patient groups. The authors found that TRA cells are present in patients with each of these disorders and that these cells populate several nuclei in the ventral lateral tier of the thalamus. There were no large differences in the locations of TRA cells among the different diagnostic classes, although there was a difference in the incidence of TRA cells in patients with PD, who had greater than 3.8 times more cells per thalamic trajectory than patients with ET and approximately five times more cells than patients with MS or cerebellar disorders. There was an increased incidence of TRA in the thalamus of patients with PD. The location of thalamic TRA cells in patients with basal ganglia and other tremor disorders was similar.

  6. Re-Emergent Tremor of Parkinson's Disease Masquerading as Essential Tremor

    Directory of Open Access Journals (Sweden)

    Sarah Morgan

    2016-03-01

    Full Text Available Background: The re-emergent tremor of Parkinson’s disease (PD is generally recognized as a postural tremor. Phenomenology Shown: A PD patient with a re-emergent tremor occurring during a task (spiral drawing, which on the surface produced a tremor that resembled that of essential tremor (ET. Educational Value: Researchers and clinicians should be aware of features of this re-emergent tremor to help distinguish it from that of ET.

  7. Task-specific kinetic finger tremor affects the performance of carrom players.

    Science.gov (United States)

    Kahathuduwa, Chanaka N; Weerasinghe, Vajira S; Dassanayake, Tharaka L; Priyadarshana, Rajeewa; Dissanayake, Arunika L; Perera, Christine

    2016-01-01

    We aimed to determine the effect of task-specific kinetic finger tremor, as indexed by surface electromyography (EMG), on the accuracy of a carrom stroke. Surface EMG of extensor digitorum communis muscle of the playing arm was recorded during rest, isometric contraction and stroke execution in 17 male carrom players with clinically observed finger tremor and 18 skill- and age-matched controls. Log-transformed power spectral densities (LogPSDs) of surface EMG activity (signifying tremor severity) at a 1-s pre-execution period correlated with angular error of the stroke. LogPSDs in 4-10 Hz range were higher in players with tremor than controls during pre-execution (P kinetic finger tremor in carrom players. This finger tremor during the immediate pre-execution phase appears to be a significant determinant of stroke accuracy.

  8. Low-dose acute vanillin is beneficial against harmaline-induced tremors in rats.

    Science.gov (United States)

    Abdulrahman, Al Asmari; Faisal, Kunnathodi; Meshref, Ali Al Amri; Arshaduddin, Mohammed

    2017-03-01

    To study the effect of pretreatment with low doses of vanillin, a flavoring agent used as a food additive, on harmaline-induced tremor in rats. Sprague Dawley rats (110 ± 5 g) were divided into groups of six animals each. Vanillin (6.25 mg, 12.5 mg, and 25 mg/kg) was administered by gavage to different groups of rats, 30 minutes before the induction of tremor. Harmaline (10 mg/kg, i.p.) was used for the induction of tremor. The latency of onset, duration, tremor intensity, tremor index, and spontaneous locomotor activity were recorded. A separate batch of animals was used for the determination of serotonin (5HT) and 5 hydroxyindole acetic acid (5HIAA) levels in the brain. Harmaline treatment resulted in characteristic tremor that lasted for more than 2 hours and decreased the locomotor activity of rats. Pre-treatment with vanillin significantly reduced the duration, intensity, and tremor index of harmaline-treated animals. Vanillin treatment also significantly attenuated harmaline-induced decrease in the locomotor activity. An increase in 5HT levels and the changes in 5HIAA/5HT ratio observed in harmaline treated rats were significantly corrected in vanillin pretreated animals. Vanillin in low doses reduces harmaline-induced tremor in rats, probably through its modulating effect on serotonin levels in the brain. These findings suggest a beneficial effect of vanillin in essential tremor.

  9. The Effect of Mining Activity on the Occurrence of Mining Tremors in the Safety Shaft Pillar of the Kladno-Mayrau Coal Mine

    Czech Academy of Sciences Publication Activity Database

    Živor, Roman; Buben, Jiří

    16(118) (2000), s. 203-214 ISSN 1211-1910 R&D Projects: GA ČR GA105/96/1065 Institutional research plan: CEZ:AV0Z3046908 Keywords : tremor s * drifting * extraction Subject RIV: DH - Mining, incl. Coal Mining

  10. Altered Activation in Cerebellum Contralateral to Unilateral Thalamotomy May Mediate Tremor Suppression in Parkinson's Disease: A Short-Term Regional Homogeneity fMRI Study.

    Directory of Open Access Journals (Sweden)

    Zhi Wen

    Full Text Available Ventral intermediate nucleus thalamotomy is an effective treatment for Parkinson's disease tremor. However, its mechanism is still unclear.We used resting-state fMRI to investigate short-term ReHo changes after unilateral thalamotomy in tremor-dominant PD, and to speculate about its possible mechanism on tremor suppression.26 patients and 31 healthy subjects (HS were recruited. Patients were divided into two groups according to right- (rPD and left-side (lPD thalamotomy. Tremor was assessed using the 7-item scale from the Unified Parkinson's disease rating scale motor score (mUPDRS. Patients were scanned using resting state fMRI after 12h withdrawal of medication, both preoperatively (PDpre and 7- day postoperatively (PDpost, whereas healthy subjects were scanned once. The regions associated with tremor and altered ReHo due to thalamic ablation were examined.The impact of unilateral VIM thalamotomy was characterized in the frontal, parietal, temporal regions, basal ganglia, thalamus, and cerebellum. Compared with PDpre, significantly reduced ReHo was found in the left cerebellum in patients with rPDpost, and slightly decreased ReHo in the cerebellum vermis in patients with lPDpost, which was significantly higher than HS. We demonstrated a positive correlation between the ReHo values in the cerebellum (in rPD, peak coordinate [-12, -54, -21], R = 0.64, P = 0.0025, and peak coordinate [-9, -54, -18], R = 0.71, P = 0.0025; in lPD, peak coordinate [3, -45, -15], R = 0.71, P = 0.004 in the pre-surgical condition, changes of ReHo induced by thalamotomy (in rPD, R = 0.63, P = 0.021, R = 0.6, P = 0.009; in lPD, R = 0.58, P = 0.028 and tremor scores contralateral to the surgical side, respectively.The specific area that may be associated with PD tremor and altered ReHo due to thalamic ablation is the cerebellum. The neural basis underlying thalamotomy is complex; cerebellum involvement is far beyond cerebello-thalamic tract breakage.

  11. 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.

  12. Toward Expanding Tremor Observations in the Northern San Andreas Fault System in the 1990s

    Science.gov (United States)

    Damiao, L. G.; Dreger, D. S.; Nadeau, R. M.; Taira, T.; Guilhem, A.; Luna, B.; Zhang, H.

    2015-12-01

    The connection between tremor activity and active fault processes continues to expand our understanding of deep fault zone properties and deformation, the tectonic process, and the relationship of tremor to the occurrence of larger earthquakes. Compared to tremors in subduction zones, known tremor signals in California are ~5 to ~10 smaller in amplitude and duration. These characteristics, in addition to scarce geographic coverage, lack of continuous data (e.g., before mid-2001 at Parkfield), and absence of instrumentation sensitive enough to monitor these events have stifled tremor detection. The continuous monitoring of these events over a relatively short time period in limited locations may lead to a parochial view of the tremor phenomena and its relationship to fault, tectonic, and earthquake processes. To help overcome this, we have embarked on a project to expand the geographic and temporal scope of tremor observation along the Northern SAF system using available continuous seismic recordings from a broad array of 100s of surface seismic stations from multiple seismic networks. Available data for most of these stations also extends back into the mid-1990s. Processing and analysis of tremor signal from this large and low signal-to-noise dataset requires a heavily automated, data-science type approach and specialized techniques for identifying and extracting reliable data. We report here on the automated, envelope based methodology we have developed. We finally compare our catalog results with pre-existing tremor catalogs in the Parkfield area.

  13. 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.

  14. Corticomuscular transmission of tremor signals by propriospinal neurons in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Manzhao Hao

    Full Text Available Cortical oscillatory signals of single and double tremor frequencies act together to cause tremor in the peripheral limbs of patients with Parkinson's disease (PD. But the corticospinal pathway that transmits the tremor signals has not been clarified, and how alternating bursts of antagonistic muscle activations are generated from the cortical oscillatory signals is not well understood. This paper investigates the plausible role of propriospinal neurons (PN in C3-C4 in transmitting the cortical oscillatory signals to peripheral muscles. Kinematics data and surface electromyogram (EMG of tremor in forearm were collected from PD patients. A PN network model was constructed based on known neurophysiological connections of PN. The cortical efferent signal of double tremor frequencies were integrated at the PN network, whose outputs drove the muscles of a virtual arm (VA model to simulate tremor behaviors. The cortical efferent signal of single tremor frequency actuated muscle spindles. By comparing tremor data of PD patients and the results of model simulation, we examined two hypotheses regarding the corticospinal transmission of oscillatory signals in Parkinsonian tremor. Hypothesis I stated that the oscillatory cortical signals were transmitted via the mono-synaptic corticospinal pathways bypassing the PN network. The alternative hypothesis II stated that they were transmitted by way of PN multi-synaptic corticospinal pathway. Simulations indicated that without the PN network, the alternating burst patterns of antagonistic muscle EMGs could not be reliably generated, rejecting the first hypothesis. However, with the PN network, the alternating burst patterns of antagonist EMGs were naturally reproduced under all conditions of cortical oscillations. The results suggest that cortical commands of single and double tremor frequencies are further processed at PN to compute the alternating burst patterns in flexor and extensor muscles, and the

  15. Corticomuscular transmission of tremor signals by propriospinal neurons in Parkinson's disease.

    Science.gov (United States)

    Hao, Manzhao; He, Xin; Xiao, Qin; Alstermark, Bror; Lan, Ning

    2013-01-01

    Cortical oscillatory signals of single and double tremor frequencies act together to cause tremor in the peripheral limbs of patients with Parkinson's disease (PD). But the corticospinal pathway that transmits the tremor signals has not been clarified, and how alternating bursts of antagonistic muscle activations are generated from the cortical oscillatory signals is not well understood. This paper investigates the plausible role of propriospinal neurons (PN) in C3-C4 in transmitting the cortical oscillatory signals to peripheral muscles. Kinematics data and surface electromyogram (EMG) of tremor in forearm were collected from PD patients. A PN network model was constructed based on known neurophysiological connections of PN. The cortical efferent signal of double tremor frequencies were integrated at the PN network, whose outputs drove the muscles of a virtual arm (VA) model to simulate tremor behaviors. The cortical efferent signal of single tremor frequency actuated muscle spindles. By comparing tremor data of PD patients and the results of model simulation, we examined two hypotheses regarding the corticospinal transmission of oscillatory signals in Parkinsonian tremor. Hypothesis I stated that the oscillatory cortical signals were transmitted via the mono-synaptic corticospinal pathways bypassing the PN network. The alternative hypothesis II stated that they were transmitted by way of PN multi-synaptic corticospinal pathway. Simulations indicated that without the PN network, the alternating burst patterns of antagonistic muscle EMGs could not be reliably generated, rejecting the first hypothesis. However, with the PN network, the alternating burst patterns of antagonist EMGs were naturally reproduced under all conditions of cortical oscillations. The results suggest that cortical commands of single and double tremor frequencies are further processed at PN to compute the alternating burst patterns in flexor and extensor muscles, and the neuromuscular dynamics

  16. Characterizing Orthostatic Tremor Using a Smartphone Application.

    Science.gov (United States)

    Balachandar, Arjun; Fasano, Alfonso

    2017-01-01

    Orthostatic tremor is one of the few tremor conditions requiring an electromyogram for definitive diagnosis since leg tremor might not be visible to the naked eye. An iOS application (iSeismometer, ObjectGraph LLC, New York) using an Apple iPhone 5 (Cupertino, CA, USA) inserted into the patient's sock detected a tremor with a frequency of 16.4 Hz on both legs. The rapid and straightforward accelerometer-based recordings accomplished in this patient demonstrate the ease with which quantitative analysis of orthostatic tremor can be conducted and, importantly, demonstrates the potential application of this approach in the assessment of any lower limb tremor.

  17. Handheld Universal Diagnostic Sensor

    Science.gov (United States)

    Chan, Eugene

    2012-01-01

    The rHEALTH technology is designed to shrink an entire hospital testing laboratory onto a handheld device. A physician or healthcare provider performs the test by collecting a fingerstick of blood from a patient. The tiny volume of blood is inserted into the rHEALTH device. Inside the device is a microfluidic chip that contains small channels about the width of a human hair. These channels help move the blood and analyze the blood sample. The rHEALTH sensor uses proprietary reagents called nanostrips, which are nanoscale test strips that enable the clinical assays. The readout is performed by laser-induced fluorescence. Overall, the time from blood collection through analysis is less than a minute.

  18. Gliding and Quasi-harmonic Tremor Behaviour of Raung Volcano: November 2014 Crisis Period Case Study

    Directory of Open Access Journals (Sweden)

    Vico Luthfi Ipmawan

    2018-01-01

    Full Text Available DOI: 10.17014/ijog.5.1.13-21The seismic activity of Raung Volcano was raised on 11 November 2014. As many as 1709 tremors were recorded followed by continuous tremors appearing in late November 2014. Quasi-harmonic and gliding tremors appeared in a spectrogram on 12 November 2014. The quasi-harmonic tremors refer to tremors that have no fully harmonic form in spectrum. The gliding harmonic tremors refer to harmonic tremors that have frequency jumps with either positive or negative increment. After signal restitution processing, the Maximum Entropy Spectral Analysis (MESA method was applied in Raung recordings resulting the spectrum and the spectrogram of tremors. The quasi-harmonic tremors have the monotonic spectrum in its head and centre segment, and the harmonic one in its tails. There are twenty-four spectrums that show frequency changes between the monotonic and harmonic. The similarity between the fundamental frequency range of the monotonic and harmonic ones suggests that both signals are excited from a common resonator. The alternating of monotonic and harmonic respectively over this period is qualitatively similar with Julian’s synthetic time series about the nonlinear oscillator model. It is suggested that Raung Volcano magma pressure is sizeable to make a chaotic vibration. A pressure increasing in Raung magmatic conduit causes the increasing of P-wave velocity and makes a positive gliding frequency.

  19. Parkinsonian rest tremor can be detected accurately based on neuronal oscillations recorded from the subthalamic nucleus.

    Science.gov (United States)

    Hirschmann, J; Schoffelen, J M; Schnitzler, A; van Gerven, M A J

    2017-10-01

    To investigate the possibility of tremor detection based on deep brain activity. We re-analyzed recordings of local field potentials (LFPs) from the subthalamic nucleus in 10 PD patients (12 body sides) with spontaneously fluctuating rest tremor. Power in several frequency bands was estimated and used as input to Hidden Markov Models (HMMs) which classified short data segments as either tremor-free rest or rest tremor. HMMs were compared to direct threshold application to individual power features. Applying a threshold directly to band-limited power was insufficient for tremor detection (mean area under the curve [AUC] of receiver operating characteristic: 0.64, STD: 0.19). Multi-feature HMMs, in contrast, allowed for accurate detection (mean AUC: 0.82, STD: 0.15), using four power features obtained from a single contact pair. Within-patient training yielded better accuracy than across-patient training (0.84vs. 0.78, p=0.03), yet tremor could often be detected accurately with either approach. High frequency oscillations (>200Hz) were the best performing individual feature. LFP-based markers of tremor are robust enough to allow for accurate tremor detection in short data segments, provided that appropriate statistical models are used. LFP-based markers of tremor could be useful control signals for closed-loop deep brain stimulation. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  20. Resolving the Detailed Spatiotemporal Slip Evolution of Deep Tremor in Western Japan

    Science.gov (United States)

    Ohta, Kazuaki; Ide, Satoshi

    2017-12-01

    We study the detailed spatiotemporal behavior of deep tremor in western Japan through the development and application of a new slip inversion method. Although many studies now recognize tremor as shear slip along the plate interface manifested in low-frequency earthquake (LFE) swarms, a conventional slip inversion analysis is not available for tremor due to insufficient knowledge of source locations and Green's functions. Here we introduce synthetic template waveforms, which are typical tremor waveforms obtained by stacking LFE seismograms at arranged points along the plate interface. Using these synthetic template waveforms as substitutes for Green's functions, we invert the continuous tremor waveforms using an iterative deconvolution approach with Bayesian constraints. We apply this method to two tremor burst episodes in western and central Shikoku, Japan. The estimated slip distribution from a 12 day tremor burst episode in western Shikoku is heterogeneous, with several patchy areas of slip along the plate interface where rapid moment releases with durations of tremor burst episode that occurred coincidentally with a very low frequency earthquake (VLF), we observe that the source size of the VLF is much larger than that estimated from tremor activity in western Shikoku. These differences in the size of the slip region may dictate the visibility of VLF signals in observed seismograms, which has implications for the mechanics of slow earthquakes and subduction zone processes.

  1. 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

  2. Nonvolcanic tremors deep beneath the San Andreas Fault.

    Science.gov (United States)

    Nadeau, Robert M; Dolenc, David

    2005-01-21

    We have discovered nonvolcanic tremor activity (i.e., long-duration seismic signals with no clear P or S waves) within a transform plate boundary zone along the San Andreas Fault near Cholame, California, the inferred epicentral region of the 1857 Fort Tejon earthquake (moment magnitude approximately 7.8). The tremors occur between 20 to 40 kilometers' depth, below the seismogenic zone (the upper approximately 15 kilometers of Earth's crust where earthquakes occur), and their activity rates may correlate with variations in local earthquake activity.

  3. 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

  4. 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

    2016-01-01

    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. PMID:26843004

  5. 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

    2017-02-01

    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.

  6. Polypyrrole Actuators for Tremor Suppression

    DEFF Research Database (Denmark)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse

    2003-01-01

    Neurological tremor affecting limbs can be divided into at least 6 different types with frequencies ranging from 2 to about 20 Hz. In order to alleviate the symptoms by suppressing the tremor, sensing and actuation systems able to perform at these frequencies are needed. Electroactive polymers...... exemplify 'soft actuator' technology that may be especially suitable for use in conjunction with human limbs. The electrochemical and mechanical properties of polypyrrole dodecyl benzene sulphonate actuator films have been studied with this application in mind. The results show that the time constants...

  7. Deep Brain Stimulation of the Dentato-Rubro-Thalamic Tract: Outcomes of Direct Targeting for Tremor.

    Science.gov (United States)

    Fenoy, Albert J; Schiess, Mya C

    2017-07-01

    Targeting the dentato-rubro-thalamic tract (DRTt) has been suggested to be efficacious in deep brain stimulation (DBS) for tremor suppression, both in case reports and post-hoc analyses. This prospective observational study sought to analyze outcomes after directly targeting the DRTt in tremor patients. 20 consecutively enrolled intention tremor patients obtained pre-operative MRI with diffusion tensor (dTi) sequences. Mean baseline tremor amplitude based on The Essential Tremor Rating Assessment Scale was recorded. The DRTt was drawn for each individual on StealthViz software (Medtronic) using the dentate nucleus as the seed region and the ipsilateral pre-central gyrus as the end region and then directly targeted during surgery. Intraoperative testing confirmed successful tremor control. Post-operative analysis of electrode position relative to the DRTt was performed, as was post-operative assessment of tremor improvement. The mean age of patients was 66.8 years; mean duration of tremor was 16 years. Mean voltage for the L electrode = 3.4 V; R = 2.6 V. Mean distance from the center of the active electrode contact to the DRTt was 0.9 mm on the L, and 0.8 mm on the R. Improvement in arm tremor amplitude from baseline after DBS was significant (P tremor suppression. Accounting for hardware, software, and model limitations, depiction of the DRTt allows for placement of electrode contacts directly within the fiber tract for modulation despite any anatomical variation, which reproducibly resulted in good tremor control. © 2017 International Neuromodulation Society.

  8. Internal tremor in Parkinson's disease, multiple sclerosis, and essential tremor.

    Science.gov (United States)

    Cochrane, Graham D; Rizvi, Syed; Abrantes, Ana; Crabtree, Brigid; Cahill, Jonathan; Friedman, Joseph H

    2015-10-01

    Internal tremor (IT) is a poorly recognized symptom that has been described in Parkinson's disease (PD). Described as a feeling of tremor in the extremities or trunk without actual movement, ITs are not debilitating but can be bothersome to patients. The origin of the sensation is unknown., and ITs may be prevalent in other diseases than PD. The present study sought to expand knowledge about IT by confirming their presence in PD, and determining their prevalence in Multiple Sclerosis (MS), and Essential Tremor (ET). A survey was developed in order to determine the prevalence of IT in PD, MS, and ET and to learn what associations with various disease characteristics were present. The survey was administered to 89 consecutive PD, 70 MS, and 11 ET patients. ITs were found to be a prevalent symptom in all three disorders (32.6% of PD, 35.9% of MS, and 54.5% of ET subjects reported experiencing ITs). ITs were found to be associated both with the subjects' perceived levels of anxiety and the presence of visible tremors. ITs appear to be a common symptom in all three disorders studied. These results need to be confirmed and compared to appropriate control populations. Copyright © 2015. Published by Elsevier Ltd.

  9. Medical and surgical treatment of tremors.

    Science.gov (United States)

    Schneider, Susanne A; Deuschl, Günther

    2015-02-01

    Tremor is a hyperkinetic movement disorder characterized by rhythmic oscillations of one or more body parts. Disease severity ranges from mild to severe with various degrees of impact on quality of life. Essential tremor and parkinsonian tremor are the most common etiologic subtypes. Treatment may be challenging; although several drugs are available, response may be unsatisfactory. For some tremor forms, controlled data are scarce or completely missing and treatment is often based on anecdotal evidence. In this article, we review the current literature on tremor treatment, with a focus on common forms. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. [Speech-related tremor of lips: a focal task-specific tremor].

    Science.gov (United States)

    Morita, Shuhei; Takagi, Rieko; Miwa, Hideto; Kondo, Tomoyoshi

    2002-04-01

    We report a 66-year-old Japanese woman in whom tremor of lips appeared during speech. Her past and family histories were unremarkable. On neurological examination, there was no abnormal finding except the lip tremor. Results of laboratory findings were all within normal levels. Her MRI and EEG were normal. Surface EMG studies revealed that regular grouped discharges at a frequency of about 4-5 Hz appeared in the orbicularis oris muscle only during voluntary speaking. The tremor was not observed under conditions of a purposeless phonation or a vocalization of a simple word, suggesting that the tremor was not a vocal tremor but a task-specific tremor related to speaking. Administration of a beta-blocker and consumption of small amount of alcohol could effectively improve the tremor, possibly suggesting that this type of tremor might be a clinical variant of essential tremor.

  11. Tremor-tide correlations and near-lithostatic pore pressure on the deep San Andreas fault.

    Science.gov (United States)

    Thomas, Amanda M; Nadeau, Robert M; Bürgmann, Roland

    2009-12-24

    Since its initial discovery nearly a decade ago, non-volcanic tremor has provided information about a region of the Earth that was previously thought incapable of generating seismic radiation. A thorough explanation of the geologic process responsible for tremor generation has, however, yet to be determined. Owing to their location at the plate interface, temporal correlation with geodetically measured slow-slip events and dominant shear wave energy, tremor observations in southwest Japan have been interpreted as a superposition of many low-frequency earthquakes that represent slip on a fault surface. Fluids may also be fundamental to the failure process in subduction zone environments, as teleseismic and tidal modulation of tremor in Cascadia and Japan and high Poisson ratios in both source regions are indicative of pressurized pore fluids. Here we identify a robust correlation between extremely small, tidally induced shear stress parallel to the San Andreas fault and non-volcanic tremor activity near Parkfield, California. We suggest that this tremor represents shear failure on a critically stressed fault in the presence of near-lithostatic pore pressure. There are a number of similarities between tremor in subduction zone environments, such as Cascadia and Japan, and tremor on the deep San Andreas transform, suggesting that the results presented here may also be applicable in other tectonic settings.

  12. Tremors in white rhinoceroses (Ceratotherium simum during etorphine–azaperone immobilisation

    Directory of Open Access Journals (Sweden)

    Stephanie S. de Lange

    2017-02-01

    Full Text Available Little is known about the mechanisms causing tremors during immobilisation of rhinoceros and whether cardiorespiratory supportive interventions alter their intensity. Therefore, we set out to determine the possible mechanisms that lead to muscle tremors and ascertain whether cardiorespiratory supportive interventions affect tremor intensity. We studied tremors and physiological responses during etorphine–azaperone immobilisation in eight boma-held and 14 free-living white rhinoceroses. Repeated measures analysis of variance and a Friedman test were used to determine differences in variables over time and between interventions. Spearman and Pearson correlations were used to test for associations between variables. Tremor intensity measured objectively by activity loggers correlated well (p < 0.0001; r2 = 0.9 with visual observations. Tremor intensity was greatest when animals were severely hypoxaemic and acidaemic. Tremor intensity correlated strongly and negatively with partial pressure of oxygen (PaO2 (p = 0.0003; r2 = 0.9995 and potential of hydrogen (pH (p = 0.02, r2 = 0.97. It correlated strongly and positively with adrenaline concentrations (p = 0.003; r2 = 0.96, and adrenaline correlated strongly and negatively with PaO2 (p = 0.03; r2 = 0.95 and pH (p = 0.03; r2 = 0.94. Therefore, hypoxaemia and acidaemia were likely associated with the intensity of tremors through their activation of the release of tremorgenic levels of adrenaline. Tremors can be reduced if circulating adrenaline is reduced, and this can be achieved by the administration of butorphanol plus oxygen insufflation. Furthermore, to assist with reducing the risks associated with rhinoceros immobilisation, tremor intensity could be used as a clinical indicator of respiratory and metabolic compromise.

  13. Building a Global Catalog of Nonvolcanic Tremor Events Using an Automatic Detection Algorithm

    Science.gov (United States)

    Bagley, B. C.; Revenaugh, J.

    2009-12-01

    Nonvolcanic tremor is characterized by a long-period seismic event containing a series of low-frequency earthquakes (LFEs). Tremor has been detected in regions of subduction (e.g. Kao et. al. 2007, 2008; Shelly 2006) and beneath the San Andreas fault near Cholame, California (e.g. Nadeau and Dolenc, 2005). In some cases tremor events seem to have periodicity, and these are often referred to as episodic tremor and slip (ETS). The origin of nonvolcanic tremor has been ascribed to shear slip along plate boundaries and/or high pore-fluid pressure. The apparent periodicity and tectonic setting associated with ETS has led to the suggestion that there may be a link between ETS and megathrust earthquakes. Until recently tremor detection has been a manual process requiring visual inspection of seismic data. In areas that have dense seismic arrays (e.g. Japan) waveform cross correlation techniques have been successfully employed (e.g. Obara, 2002). Kao et al. (2007) developed an algorithm for automatic detection of seismic tremor that can be used in regions without dense arrays. This method has been used to create the Tremor Activity Monitoring System (TAMS), which is used by the Geologic Survey of Canada to monitor northern Cascadia. So far the study of nonvolcanic tremor has been limited to regions of subduction or along major transform faults. It is unknown if tremor events occur in other tectonic settings, or if the current detection schemes will be useful for finding them. We propose to look for tremor events in non-subduction regions. It is possible that if tremor exists in other regions it will have different characteristics and may not trigger the TAMS system or be amenable to other existing detection schemes. We are developing algorithms for searching sparse array data sets for quasi-harmonic energy bursts in hopes of recognizing and cataloging nonvolcanic tremor in an expanded tectonic setting. Statistical comparisons against the TAMS algorithm will be made if

  14. Inhibition of Parkinsonian tremor with cutaneous afferent evoked by transcutaneous electrical nerve stimulation.

    Science.gov (United States)

    Hao, Man-Zhao; Xu, Shao-Qin; Hu, Zi-Xiang; Xu, Fu-Liang; Niu, Chuan-Xin M; Xiao, Qin; Lan, Ning

    2017-07-14

    Recent study suggests that tremor signals are transmitted by way of multi-synaptic corticospinal pathway. Neurophysiological studies have also demonstrated that cutaneous afferents exert potent inhibition to descending motor commands by way of spinal interneurons. We hypothesize in this study that cutaneous afferents could also affect the transmission of tremor signals, thus, inhibit tremor in patients with PD. We tested this hypothesis by activating cutaneous afferents in the dorsal hand skin innervated by superficial radial nerve using transcutaneous electrical nerve stimulation (TENS). Eight patients with PD having tremor dominant symptom were recruited to participate in this study using a consistent experimental protocol for tremor inhibition. Resting tremor and electromyogram (EMG) of muscles in the upper extremity of these subjects with PD were recorded, while surface stimulation was applied to the dorsal skin of the hand. Fifteen seconds of data were recorded for 5 s prior to, during and post stimulation. Power spectrum densities (PSDs) of tremor and EMG signals were computed for each data segment. The peak values of PSDs in three data segments were compared to detect evidence of tremor inhibition. At stimulation intensity from 1.5 to 1.75 times of radiating sensation threshold, apparent suppressions of tremor at wrist, forearm and upper arm and in the EMGs were observed immediately at the onset of stimulation. After termination of stimulation, tremor and rhythmic EMG bursts reemerged gradually. Statistical analysis of peak spectral amplitudes showed a significant difference in joint tremors and EMGs during and prior to stimulation in all 8 subjects with PD. The average percentage of suppression was 61.56% in tremor across all joints of all subjects, and 47.97% in EMG of all muscles. The suppression appeared to occur mainly in distal joints and muscles. There was a slight, but inconsistent effect on tremor frequency in the 8 patients with PD tested. Our

  15. An Enhanced Intelligent Handheld Instrument with Visual Servo Control for 2-DOF Hand Motion Error Compensation

    Directory of Open Access Journals (Sweden)

    Yan Naing Aye

    2013-10-01

    Full Text Available The intelligent handheld instrument, ITrem2, enhances manual positioning accuracy by cancelling erroneous hand movements and, at the same time, provides automatic micromanipulation functions. Visual data is acquired from a high speed monovision camera attached to the optical surgical microscope and acceleration measurements are acquired from the inertial measurement unit (IMU on board ITrem2. Tremor estimation and canceling is implemented via Band-limited Multiple Fourier Linear Combiner (BMFLC filter. The piezoelectric actuated micromanipulator in ITrem2 generates the 3D motion to compensate erroneous hand motion. Preliminary bench-top 2-DOF experiments have been conducted. The error motions simulated by a motion stage is reduced by 67% for multiple frequency oscillatory motions and 56.16% for pre-conditioned recorded physiological tremor.

  16. Diagnosis and Treatment of Common Forms of Tremor

    Science.gov (United States)

    Puschmann, Andreas; Wszolek, Zbigniew K.

    2014-01-01

    Tremor is the most common movement disorder presenting to an outpatient neurology practice and is defined as a rhythmical, involuntary oscillatory movement of a body part. The authors review the clinical examination, classification, and diagnosis of tremor. The pathophysiology of the more common forms of tremor is outlined, and treatment options are discussed. Essential tremor is characterized primarily by postural and action tremors, may be a neurodegenerative disorder with pathologic changes in the cerebellum, and can be treated with a wide range of pharmacologic and nonpharmacologic methods. Tremor at rest is typical for Parkinson’s disease, but may arise independently of a dopaminergic deficit. Enhanced physiologic tremor, intention tremor, and dystonic tremor are discussed. Further differential diagnoses described in this review include drug- or toxin-induced tremor, neuropathic tremor, psychogenic tremor, orthostatic tremor, palatal tremor, tremor in Wilson’s disease, and tremor secondary to cerebral lesions, such as Holmes’ tremor (midbrain tremor). An individualized approach to treatment of tremor patients is important, taking into account the degree of disability, including social embarrassment, which the tremor causes in the patient’s life. PMID:21321834

  17. Digital forensics for handheld devices

    CERN Document Server

    Doherty, Eamon P

    2012-01-01

    Approximately 80 percent of the world's population now owns a cell phone, which can hold evidence or contain logs about communications concerning a crime. Cameras, PDAs, and GPS devices can also contain information related to corporate policy infractions and crimes. Aimed to prepare investigators in the public and private sectors, Digital Forensics for Handheld Devices examines both the theoretical and practical aspects of investigating handheld digital devices. This book touches on all areas of mobile device forensics, including topics from the legal, technical, academic, and social aspects o

  18. Using Portable Transducers to Measure Tremor Severity

    Directory of Open Access Journals (Sweden)

    Rodger Elble

    2016-05-01

    Full Text Available Background: Portable motion transducers, suitable for measuring tremor, are now available at a reasonable cost. The use of these transducers requires knowledge of their limitations and data analysis. The purpose of this review is to provide a practical overview and example software for using portable motion transducers in the quantification of tremor. Methods: Medline was searched via PubMed.gov in December 2015 using the Boolean expression “tremor AND (accelerometer OR accelerometry OR gyroscope OR inertial measurement unit OR digitizing tablet OR transducer.” Abstracts of 419 papers dating back to 1964 were reviewed for relevant portable transducers and methods of tremor analysis, and 105 papers written in English were reviewed in detail. Results: Accelerometers, gyroscopes, and digitizing tablets are used most commonly, but few are sold for the purpose of measuring tremor. Consequently, most software for tremor analysis is developed by the user. Wearable transducers are capable of recording tremor continuously, in the absence of a clinician. Tremor amplitude, frequency, and occurrence (percentage of time with tremor can be computed. Tremor amplitude and occurrence correlate strongly with clinical ratings of tremor severity. Discussion: Transducers provide measurements of tremor amplitude that are objective, precise, and valid, but the precision and accuracy of transducers are mitigated by natural variability in tremor amplitude. This variability is so great that the minimum detectable change in amplitude, exceeding random variability, is comparable for scales and transducers. Research is needed to determine the feasibility of detecting smaller change using averaged data from continuous long-term recordings with wearable transducers.

  19. Olfaction and essential tremor Olfato no tremor essencial

    Directory of Open Access Journals (Sweden)

    Lucas Barasnevicius Quagliato

    2009-03-01

    Full Text Available OBJECTIVE: To characterize the olfactory identification in 40 essential tremor (ET patients, with the University of Pennsylvania 12 Smell Identification Test (UPSIT, to correlate UPSIT scores to clinical and epidemiological data and to compare it to 89 aged matched controls. METHOD: Patients were assessed using ET Clinical Scale of Evaluation and UPSIT. RESULTS: In patients with ET, the UPSIT medium score was 9.10, similar to the control group (9.11, which was also observed in all age groups. ET severity did not correlate to UPSIT scores. CONCLUSION: This study demonstrated normality of olfactory identification on ET, qualifying UPSIT to be an important tool on tremor differential diagnosis of undetermined origin.OBJETIVO: Caracterizar a identificação olfatória em 40 pacientes com tremor essencial, através do Teste de Identificação de 12 Cheiros da Universidade de Pensilvânia (TICUP, correlacioná-la aos dados clínicos e epidemiológicos e compará-la com 89 indivíduos normais. MÉTODO: Os pacientes foram avaliados com a Escala Clínica de Avaliação do TE e com o TICUP. RESULTADOS: A média de acertos no TICUP nos pacientes com TE foi 9,10, semelhante à do grupo controle (9,11, sendo isso observado em todas as faixas etárias. A gravidade do TE não se correlacionou com o resultado do TICUP. CONCLUSÃO: Este estudo demonstrou normalidade da identificação olfatória no TE, qualificando o TICUP como ferramenta importante no diagnóstico diferencial dos tremores de causa indeterminada.

  20. A Mixed-Methods, Randomized, Controlled Feasibility Trial to Inform the Design of a Phase III Trial to Test the Effect of the Handheld Fan on Physical Activity and Carer Anxiety in Patients With Refractory Breathlessness.

    Science.gov (United States)

    Johnson, Miriam J; Booth, Sara; Currow, David C; Lam, Lawrence T; Phillips, Jane L

    2016-05-01

    The handheld fan is an inexpensive and safe way to provide facial airflow, which may reduce the sensation of chronic refractory breathlessness, a frequently encountered symptom. To test the feasibility of developing an adequately powered, multicenter, multinational randomized controlled trial comparing the efficacy of a handheld fan and exercise advice with advice alone in increasing activity in people with chronic refractory breathlessness from a variety of medical conditions, measuring recruitment rates; data quality; and potential primary outcome measures. This was a Phase II, multisite, international, parallel, nonblinded, mixed-methods randomized controlled trial. Participants were centrally randomized to fan or control. All received breathlessness self-management/exercise advice and were followed up weekly for four weeks. Participants/carers were invited to participate in a semistructured interview at the study's conclusion. Ninety-seven people were screened, 49 randomized (mean age 68 years; 49% men), and 43 completed the study. Site recruitment varied from 0.25 to 3.3/month and screening:randomization from 1.1:1 to 8.5:1. There were few missing data except for the Chronic Obstructive Pulmonary Disease Self-Efficacy Scale (two-thirds of data missing). No harms were observed. Three interview themes included 1) a fan is a helpful self-management strategy, 2) a fan aids recovery, and 3) a symptom control trial was welcome. A definitive, multisite trial to study the use of the handheld fan as part of self-management of chronic refractory breathlessness is feasible. Participants found the fan useful. However, the value of information for changing practice or policy is unlikely to justify the expense of such a trial, given perceived benefits, the minimal costs, and an absence of harms demonstrated in this study. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  1. Differential Diagnosis of Parkinson Disease, Essential Tremor, and Enhanced Physiological Tremor with the Tremor Analysis of EMG

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    2017-01-01

    Full Text Available We investigate the differential diagnostic value of tremor analysis of EMG on Parkinson’s disease (PD, essential tremor (ET, and enhanced physiological tremor (EPT. Clinical data from 25 patients with PD, 20 patients with ET, and 20 patients with EPT were collected. The tremor frequency and muscle contraction pattern of the resting, posture, and 500 g and 1000 g overload were recorded. The frequency of PD tremor was 4–6 Hz, and the frequency of ET was also in this range; the frequency of EPT is 6–12 hz having some overlap with PD. The muscle contraction patterns of the ET and EPT group were mainly synchronous contraction, and the muscle contraction mode of the PD group was mainly alternating contraction. Having tremor latency from rest to postural position and having changes in tremor amplitude after mental concentration in PD might distinguish ET. Tremor analysis of EMG was able to distinguish PD from ET and EPT by varying the tremor frequency and muscle contraction pattern. It can also differentiate between PD and ET by the latency and concentration effect and ET and EPT by weight load effect.

  2. Characterizing Orthostatic Tremor Using a Smartphone Application

    Directory of Open Access Journals (Sweden)

    Arjun Balachandar

    2017-07-01

    Full Text Available Background: Orthostatic tremor is one of the few tremor conditions requiring an electromyogram for definitive diagnosis since leg tremor might not be visible to the naked eye.Phenomenology Shown: An iOS application (iSeismometer, ObjectGraph LLC, New York using an Apple iPhone 5 (Cupertino, CA, USA inserted into the patient’s sock detected a tremor with a frequency of 16.4 Hz on both legs.Educational Value: The rapid and straightforward accelerometer-based recordings accomplished in this patient demonstrate the ease with which quantitative analysis of orthostatic tremor can be conducted and, importantly, demonstrates the potential application of this approach in the assessment of any lower limb tremor

  3. Rest tremor in idiopathic adult-onset dystonia.

    Science.gov (United States)

    Gigante, A F; Berardelli, A; Defazio, G

    2016-05-01

    Tremor in dystonia has been described as a postural or kinetic abnormality. In recent series, however, patients with idiopathic adult-onset dystonia also displayed rest tremor. The frequency and distribution of rest tremor were studied in a cohort of 173 consecutive Italian patients affected by various forms of idiopathic adult-onset dystonia attending our movement disorder clinic over 8 months. Examination revealed tremor in 59/173 patients (34%): 12 patients had head tremor, 34 patients had arm tremor, whilst 13 patients presented tremor in both sites. Head tremor was postural in all patients, whereas arm tremor was postural/kinetic in 28 patients, only at rest in one and both postural/kinetic and at rest in 18 patients. Patients with tremor were more likely to have segmental/multifocal dystonia. Patients who had rest tremor (either alone or associated with action tremor) had a higher age at dystonia onset and a greater frequency of dystonic arm involvement than patients with action tremor alone or without tremor. Both action and rest tremor are part of the tremor spectrum of adult-onset dystonia and are more frequently encountered in segmental/multifocal dystonia. The higher age at dystonia onset and the greater frequency of arm dystonia in patients with rest tremor may have pathophysiological implications and may account, at least in part, for the previous lack of identification of rest tremor as one possible type of tremor present in dystonia. © 2016 EAN.

  4. Hand-held medical robots.

    Science.gov (United States)

    Payne, Christopher J; Yang, Guang-Zhong

    2014-08-01

    Medical robots have evolved from autonomous systems to tele-operated platforms and mechanically-grounded, cooperatively-controlled robots. Whilst these approaches have seen both commercial and clinical success, uptake of these robots remains moderate because of their high cost, large physical footprint and long setup times. More recently, researchers have moved toward developing hand-held robots that are completely ungrounded and manipulated by surgeons in free space, in a similar manner to how conventional instruments are handled. These devices provide specific functions that assist the surgeon in accomplishing tasks that are otherwise challenging with manual manipulation. Hand-held robots have the advantages of being compact and easily integrated into the normal surgical workflow since there is typically little or no setup time. Hand-held devices can also have a significantly reduced cost to healthcare providers as they do not necessitate the complex, multi degree-of-freedom linkages that grounded robots require. However, the development of such devices is faced with many technical challenges, including miniaturization, cost and sterility, control stability, inertial and gravity compensation and robust instrument tracking. This review presents the emerging technical trends in hand-held medical robots and future development opportunities for promoting their wider clinical uptake.

  5. Effect of stretching and proprioceptive loading in hand function among patients with cerebellar tremor

    Directory of Open Access Journals (Sweden)

    Hariharasudhan Ravichandran

    2016-01-01

    Full Text Available Background and Objective: Tremor, the most common form of abnormal involuntary movement, affects the performance of activities of daily living. Evidence on effective form of physiotherapy techniques which can help manage intentional tremor and improve hand function among cerebellar dysfunction patients in inconclusive. Hence, this study aims to establish the effectiveness of stretching and proprioceptive loading among cerebellar patients with intentional tremors. The objective of this study is to compare the efficacy of stretching and proprioceptive loading among patients with cerebellar intention tremor. Materials and Methods: A total of thirty patients with intention tremor due to cerebellar lesion were recruited for this study. They were randomized into two groups, Group I received stretching exercise and Group II received proprioceptive loading exercise. Pre- and post-test outcome measures were taken at the end of duration of 3 weeks intervention. Outcome measures were Fahn's tremor rating scale and nine hole peg test. Results: Statistical analyses were done by McNemar test, Wilcoxon's signed rank test, and Mann–Whitney test. Post-test scores of both groups were compared and found that Group II treated with proprioceptive loading exercise had higher significant result than the group treated with strengthening exercise program. Conclusion: Proprioceptive loading exercise has demonstrated signifi cant effect on reducing cerebellar tremor and improving muscle coordination in reaching activities.

  6. 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.

  7. Impaired emotion processing in functional (psychogenic tremor: A functional magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Alberto J. Espay

    2018-01-01

    Conclusions: In response to emotional stimuli, functional tremor is associated with alterations in activation and functional connectivity in networks involved in emotion processing and theory of mind. These findings may be relevant to the pathophysiology of functional movement disorders.

  8. Control of lithium tremor with propranolol.

    Science.gov (United States)

    Lapierre, Y D

    1976-04-03

    Lithium tremor is an irregular, nonrhythmic tremor of the distal extremities, variable in both intensity and frequency. It is clinically differentiated from essential tremor and tremors due to anxiety and neuroleptics. The pathophysiologic mechanisms are hypothesized to be of perpheral origin. Five patients were successfully treated with propranolol. In general, the dosage of propranolol must be individually adjusted and is usually from 30 to 40 mg daily in divided doses. This blocker of beta-adrenergic receptors remains effective with long-term administration and increases in dosage are not required.

  9. Neural computational modeling reveals a major role of corticospinal gating of central oscillations in the generation of essential tremor

    Directory of Open Access Journals (Sweden)

    Hong-en Qu

    2017-01-01

    Full Text Available Essential tremor, also referred to as familial tremor, is an autosomal dominant genetic disease and the most common movement disorder. It typically involves a postural and motor tremor of the hands, head or other part of the body. Essential tremor is driven by a central oscillation signal in the brain. However, the corticospinal mechanisms involved in the generation of essential tremor are unclear. Therefore, in this study, we used a neural computational model that includes both monosynaptic and multisynaptic corticospinal pathways interacting with a propriospinal neuronal network. A virtual arm model is driven by the central oscillation signal to simulate tremor activity behavior. Cortical descending commands are classified as alpha or gamma through monosynaptic or multisynaptic corticospinal pathways, which converge respectively on alpha or gamma motoneurons in the spinal cord. Several scenarios are evaluated based on the central oscillation signal passing down to the spinal motoneurons via each descending pathway. The simulated behaviors are compared with clinical essential tremor characteristics to identify the corticospinal pathways responsible for transmitting the central oscillation signal. A propriospinal neuron with strong cortical inhibition performs a gating function in the generation of essential tremor. Our results indicate that the propriospinal neuronal network is essential for relaying the central oscillation signal and the production of essential tremor.

  10. Neural computational modeling reveals a major role of corticospinal gating of central oscillations in the generation of essential tremor.

    Science.gov (United States)

    Qu, Hong-En; Niu, Chuanxin M; Li, Si; Hao, Man-Zhao; Hu, Zi-Xiang; Xie, Qing; Lan, Ning

    2017-12-01

    Essential tremor, also referred to as familial tremor, is an autosomal dominant genetic disease and the most common movement disorder. It typically involves a postural and motor tremor of the hands, head or other part of the body. Essential tremor is driven by a central oscillation signal in the brain. However, the corticospinal mechanisms involved in the generation of essential tremor are unclear. Therefore, in this study, we used a neural computational model that includes both monosynaptic and multisynaptic corticospinal pathways interacting with a propriospinal neuronal network. A virtual arm model is driven by the central oscillation signal to simulate tremor activity behavior. Cortical descending commands are classified as alpha or gamma through monosynaptic or multisynaptic corticospinal pathways, which converge respectively on alpha or gamma motoneurons in the spinal cord. Several scenarios are evaluated based on the central oscillation signal passing down to the spinal motoneurons via each descending pathway. The simulated behaviors are compared with clinical essential tremor characteristics to identify the corticospinal pathways responsible for transmitting the central oscillation signal. A propriospinal neuron with strong cortical inhibition performs a gating function in the generation of essential tremor. Our results indicate that the propriospinal neuronal network is essential for relaying the central oscillation signal and the production of essential tremor.

  11. Electrocorticography reveals beta desynchronization in the basal ganglia-cortical loop during rest tremor in Parkinson's disease.

    Science.gov (United States)

    Qasim, Salman E; de Hemptinne, Coralie; Swann, Nicole C; Miocinovic, Svjetlana; Ostrem, Jill L; Starr, Philip A

    2016-02-01

    The pathophysiology of rest tremor in Parkinson's disease (PD) is not well understood, and its severity does not correlate with the severity of other cardinal signs of PD. We hypothesized that tremor-related oscillatory activity in the basal-ganglia-thalamocortical loop might serve as a compensatory mechanism for the excessive beta band synchronization associated with the parkinsonian state. We recorded electrocorticography (ECoG) from the sensorimotor cortex and local field potentials (LFP) from the subthalamic nucleus (STN) in patients undergoing lead implantation for deep brain stimulation (DBS). We analyzed differences in measures of network synchronization during epochs of spontaneous rest tremor, versus epochs without rest tremor, occurring in the same subjects. The presence of tremor was associated with reduced beta power in the cortex and STN. Cortico-cortical coherence and phase-amplitude coupling (PAC) decreased during rest tremor, as did basal ganglia-cortical coherence in the same frequency band. Cortical broadband gamma power was not increased by tremor onset, in contrast to the movement-related gamma increase typically observed at the onset of voluntary movement. These findings suggest that the cortical representation of rest tremor is distinct from that of voluntary movement, and support a model in which tremor acts to decrease beta band synchronization within the basal ganglia-cortical loop. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Kaasinen, Valtteri; Kinos, Maija; Joutsa, Juho; Seppaenen, Marko; Noponen, Tommi

    2014-01-01

    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. [ 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.)

  13. Drug-induced tremor

    Science.gov (United States)

    ... may include: Alcohol withdrawal Cigarette smoking Overactive thyroid ( hyperthyroidism ) Parkinson disease Adrenal gland tumor ( pheochromocytoma ) Too much ... your activity or is accompanied by other symptoms. Prevention Always tell your provider about the medicines you ...

  14. Tremor in neurodegenerative ataxias, Huntington disease and tic disorder.

    Science.gov (United States)

    Rudzińska, M; Krawczyk, M; Wójcik-Pędziwiatr, M; Szczudlik, A; Tomaszewski, T

    2013-01-01

    Tremor is the most prevalent movement disorder, defined as rhythmic oscillations of a body part, caused by alternating or synchronic contractions of agonistic or antagonistic muscles. The aim of the study was to assess prevalence and to characterize parameters of tremor accompanying de-generative ataxias, Huntington disease (HD) and tic disorders in comparison with a control group. Forty-three patients with degenerative ataxias, 28 with HD and 26 with tic disorders together with 51 healthy controls were included in the study. For each participant, clinical and instrumental assessment (accelerometer, electromyography [EMG], graphic tablet) of hand tremor was performed. Frequency and severity of tremor were assessed in three positions: at rest (rest tremor), with hands extended (postural tremor), during the 'finger-to-nose' test and during Archimedes spiral drawing (kinetic tremor). Based on the mass load test, the type of tremor was determined as essential tremor type or enhanced physiological tremor type. The incidence of tremor in the accelerometry in patients with degenerative ataxia (50%) significantly differs from controls (10%) (p = 0.001). The dominant tremor was postural, low-intense, with 7-Hz frequency, essential tremor (23%) or other tremor type (23%), while enhanced physiological tremor was the least frequent (2%). Tremor in patients with HD and tic disorders was found in 10% and 20% of patients, respectively, similarly to the control group. Tremor was mild, postural and of essential tremor type, less frequently of enhanced physiological tremor type. No correlation between severity of tremor and severity of disease was found. The prevalence of tremor is considerably higher among patients with degenerative ataxias compared with HD, tic disorder and the control group. The most common type of tremor accompanying ataxias, HD and tic disorders is essential tremor type.

  15. 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.

  16. Teleseismically-induced tremor near Parkfield, CA - a cacophony or a symphony?

    Science.gov (United States)

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

    2007-12-01

    The tremor triggered near Parkfield, CA by the 2002 Denali and 2004 Sumatra earthquakes was strong and well recorded by the dense regional CISN and the borehole HRSN networks. Peng et al. (this meeting) survey tremors triggered by a larger set of 12 regional and teleseismic events, providing a broader context. In the case of both the 2002 M7.9 Denali and 2004 M9.1 Sumatra earthquakes, the tremor emanates from at least two source regions deep within the SAF. The first source region is 40 km NW of the SAFOD in the creeping section of the SAF, and the second region is 40 km SE of the SAFOD near Cholame, close to the location where most of the non-triggered tremor has been found previously (Nadeau and Dolenc, Science, 2005). The Denali earthquake triggered tremor is in phase with the surface waves for about 400s. The northern region started tremoring first by about 100s, and both regions quieted before the end of the surface waves. The wavetrain for the 2004 M9.1 Sumatra earthquake was long enough that tremors were also excited by the weak diffracted P waves, and tremor turned up the volume for an hour upon the arrival of the surface waves, underwent a sudden and curious hiatus for 500s before the end of the surface waves, then re-started and continued for at least an hour after the passage of the surface waves. It is easy to suggest that the tremor was accompanied by deep slip on the SAF, but creep and strain data indicate any slip was too small to generate a detectable surface deformation. These observations suggest a component of driven, instantaneous, perhaps Coulomb-friction response with an added dose of self-sustaining, dribbling activity more suggestive of the oozing of fluids.

  17. Network-Based Detection and Classification of Seismovolcanic Tremors: Example From the Klyuchevskoy Volcanic Group in Kamchatka

    Science.gov (United States)

    Soubestre, Jean; Shapiro, Nikolai M.; Seydoux, Léonard; de Rosny, Julien; Droznin, Dmitry V.; Droznina, Svetlana Ya.; Senyukov, Sergey L.; Gordeev, Evgeniy I.

    2018-01-01

    We develop a network-based method for detecting and classifying seismovolcanic tremors. The proposed approach exploits the coherence of tremor signals across the network that is estimated from the array covariance matrix. The method is applied to four and a half years of continuous seismic data recorded by 19 permanent seismic stations in the vicinity of the Klyuchevskoy volcanic group in Kamchatka (Russia), where five volcanoes were erupting during the considered time period. We compute and analyze daily covariance matrices together with their eigenvalues and eigenvectors. As a first step, most coherent signals corresponding to dominating tremor sources are detected based on the width of the covariance matrix eigenvalues distribution. Thus, volcanic tremors of the two volcanoes known as most active during the considered period, Klyuchevskoy and Tolbachik, are efficiently detected. As a next step, we consider the daily array covariance matrix's first eigenvector. Our main hypothesis is that these eigenvectors represent the principal components of the daily seismic wavefield and, for days with tremor activity, characterize dominant tremor sources. Those daily first eigenvectors, which can be used as network-based fingerprints of tremor sources, are then grouped into clusters using correlation coefficient as a measure of the vector similarity. As a result, we identify seven clusters associated with different periods of activity of four volcanoes: Tolbachik, Klyuchevskoy, Shiveluch, and Kizimen. The developed method does not require a priori knowledge and is fully automatic; and the database of the network-based tremor fingerprints can be continuously enriched with newly available data.

  18. Statistical properties of mine tremor aftershocks

    CSIR Research Space (South Africa)

    Kgarume, TE

    2010-02-01

    Full Text Available Mine tremors and their aftershocks pose a risk to mine workers in the deep gold mines of South Africa. The statistical properties of mine-tremor aftershocks were investigated as part of an endeavour to assess the hazard and manage the risk. Data...

  19. Triggered tremor sweet spots in Alaska

    Science.gov (United States)

    Gomberg, Joan; Prejean, Stephanie

    2013-01-01

    To better understand what controls fault slip along plate boundaries, we have exploited the abundance of seismic and geodetic data available from the richly varied tectonic environments composing Alaska. A search for tremor triggered by 11 large earthquakes throughout all of seismically monitored Alaska reveals two tremor “sweet spots”—regions where large-amplitude seismic waves repeatedly triggered tremor between 2006 and 2012. The two sweet spots locate in very different tectonic environments—one just trenchward and between the Aleutian islands of Unalaska and Akutan and the other in central mainland Alaska. The Unalaska/Akutan spot corroborates previous evidence that the region is ripe for tremor, perhaps because it is located where plate-interface frictional properties transition between stick-slip and stably sliding in both the dip direction and laterally. The mainland sweet spot coincides with a region of complex and uncertain plate interactions, and where no slow slip events or major crustal faults have been noted previously. Analyses showed that larger triggering wave amplitudes, and perhaps lower frequencies (tremor. However, neither the maximum amplitude in the time domain or in a particular frequency band, nor the geometric relationship of the wavefield to the tremor source faults alone ensures a high probability of triggering. Triggered tremor at the two sweet spots also does not occur during slow slip events visually detectable in GPS data, although slow slip below the detection threshold may have facilitated tremor triggering.

  20. Treatment of lithium induced tremor with atenolol.

    Science.gov (United States)

    Davé, M

    1989-03-01

    This is the first report on the successful treatment of one patient with lithium induced tremor with hydrophilic atenolol, which is a relatively selective beta 1 adrenergic receptor blocker. Atenolol's advantages over lipophilic beta blockers in the treatment of lithium induced tremor are discussed.

  1. Afterslip, tremor, and the Denali fault earthquake

    Science.gov (United States)

    Gomberg, Joan; Prejean, Stephanie; Ruppert, Natalia

    2012-01-01

    We tested the hypothesis that afterslip should be accompanied by tremor using observations of seismic and aseismic deformation surrounding the 2002 M 7.9 Denali fault, Alaska, earthquake (DFE). Afterslip happens more frequently than spontaneous slow slip and has been observed in a wider range of tectonic environments, and thus the existence or absence of tremor accompanying afterslip may provide new clues about tremor generation. We also searched for precursory tremor, as a proxy for posited accelerating slip leading to rupture. Our search yielded no tremor during the five days prior to the DFE or in several intervals in the three months after. This negative result and an array of other observations all may be explained by rupture penetrating below the presumed locked zone into the frictional transition zone. While not unique, such an explanation corroborates previous models of megathrust and transform earthquake ruptures that extend well into the transition zone.

  2. Human Handheld-Device Interaction : An Adaptive User Interface

    NARCIS (Netherlands)

    Fitrianie, S.

    2010-01-01

    The move to smaller, lighter and more powerful (mobile) handheld devices, whe-ther PDAs or smart-phones, looks like a trend that is building up speed. With numerous embedded technologies and wireless connectivity, the drift opens up unlimited opportunities in daily activities that are both more

  3. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

    DEFF Research Database (Denmark)

    Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig

    2013-01-01

    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...... 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....

  4. Square biphasic pulse deep brain stimulation for essential tremor: The BiP tremor study.

    Science.gov (United States)

    De Jesus, Sol; Almeida, Leonardo; Shahgholi, Leili; Martinez-Ramirez, Daniel; Roper, Jaimie; Hass, Chris J; Akbar, Umer; Wagle Shukla, Aparna; Raike, Robert S; Okun, Michael S

    2018-01-01

    Conventional deep brain stimulation (DBS) utilizes regular, high frequency pulses to treat medication-refractory symptoms in essential tremor (ET). Modifications of DBS pulse shape to achieve improved effectiveness is a promising approach. The current study assessed the safety, tolerability and effectiveness of square biphasic pulse shaping as an alternative to conventional ET DBS. This pilot study compared biphasic pulses (BiP) versus conventional DBS pulses (ClinDBS). Eleven ET subjects with clinically optimized ventralis intermedius nucleus DBS were enrolled. Objective measures were obtained over 3 h while ON BiP stimulation. There was observed benefit in the Fahn-Tolosa Tremor Rating Scale (TRS) for BiP conditions when compared to the DBS off condition and to ClinDBS setting. Total TRS scores during the DBS OFF condition (28.5 IQR = 24.5-35.25) were significantly higher than the other time points. Following active DBS, TRS improved to (20 IQR = 13.8-24.3) at ClinDBS setting and to (16.5 IQR = 12-20.75) at the 3 h period ON BiP stimulation (p = 0.001). Accelerometer recordings revealed improvement in tremor at rest (χ 2  = 16.1, p = 0.006), posture (χ 2  = 15.9, p = 0.007) and with action (χ 2  = 32.1, p=<0.001) when comparing median total scores at ClinDBS and OFF DBS conditions to 3 h ON BiP stimulation. There were no adverse effects and gait was not impacted. BiP was safe, tolerable and effective on the tremor symptoms when tested up to 3 h. This study demonstrated the feasibility of applying a novel DBS waveform in the clinic setting. Larger prospective studies with longer clinical follow-up will be required. Copyright © 2017. Published by Elsevier Ltd.

  5. 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.

  6. 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.

  7. 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

  8. Precise Relative Location of San Andreas Fault Tremors Near Cholame, CA, Using Seismometer Clusters: Slip on the Deep Extension of the Fault?

    Science.gov (United States)

    Shelly, D. R.; Ellsworth, W. L.; Ryberg, T.; Haberland, C.; Fuis, G.; Murphy, J.; Nadeau, R.; Bürgmann, R.

    2008-12-01

    Non-volcanic tremor, similar in character to that generated at some subduction zones, was recently identified beneath the strike-slip San Andreas Fault (SAF) in central California (Nadeau and Dolenc, 2005). Using a matched filter method, we closely examine a 24-hour period of active SAF tremor and show that, like tremor in the Nankai Trough subduction zone, this tremor is composed of repeated similar events. We take advantage of this similarity to locate detected similar events relative to several chosen events. While low signal-to-noise makes location challenging, we compensate for this by estimating event-pair differential times at 'clusters' of nearby temporary and permanent stations rather than at single stations. We find that the relative locations consistently form a near-linear structure in map view, striking parallel to the surface trace of the SAF. Therefore, we suggest that at least a portion of the tremor occurs on the deep extension of the fault, similar to the situation for subduction zone tremor. Also notable is the small depth range (a few hundred meters or less) of many of the located tremors, a feature possibly analogous to earthquake streaks observed on the shallower portion of the fault. The close alignment of the tremor with the SAF slip orientation suggests a shear slip mechanism, as has been argued for subduction tremor. At times, we observe a clear migration of the tremor source along the fault, at rates of 15-40 km/hr.

  9. Beta 1 versus nonselective blockade in therapy of essential tremor.

    Science.gov (United States)

    Larsen, T A; Teräväinen, H

    1983-01-01

    The beta 1-selective blocker metoprolol was compared to propranolol and a placebo in a double-blind crossover trial in 24 patients with essential tremor. Both beta blockers suppressed the essential tremor, but metoprolol, which caused a mean reduction of 32.0% in tremor intensity from the base-line value, was less effective than propranolol, which reduced mean tremor intensity by 41.3%. Subjective benefit for their tremor was found by 15 of the patients taking propranolol and by one taking metoprolol. The tremor frequency was not affected. No serious side effects were observed. Metoprolol may offer an alternative for those essential tremor patients who cannot tolerate propranolol.

  10. 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.

  11. Development of Tremor Suppression Control System Using Adaptive Filter and Its Application to Meal-assist Robot

    Science.gov (United States)

    Yano, Ken'ichi; Ohara, Eiichi; Horihata, Satoshi; Aoki, Takaaki; Nishimoto, Yutaka

    A robot that supports independent living by assisting with eating and other activities which use the operator's own hand would be helpful for people suffering from tremors of the hand or any other body part. The proposed system using adaptive filter estimates tremor frequencies with a time-varying property and individual differences online. In this study, the estimated frequency is used to adjusting the tremor suppression filter which insulates the voluntary motion signal from the sensor signal containing tremor components. These system are integrated into the control system of the Meal-Assist Robot. As a result, the developed system makes it possible for the person with a tremor to manipulate the supporting robot without causing operability to deteriorate and without hazards due to improper operation.

  12. Hand-held optical sensor using denatured antibody coated electro-active polymer for ultra-trace detection of copper in blood serum and environmental samples.

    Science.gov (United States)

    Chandra, Sutapa; Dhawangale, Arvind; Mukherji, Soumyo

    2018-07-01

    An optimum copper concentration in environment is highly desired for all forms of life. We have developed an ultrasensitive copper sensor which functions from femto to micro molar concentration accurately (R 2 = 0.98). The sensor is based on denatured antibody immunoglobulin G (IgG), immobilized on polyaniline (PAni) which in turn is the coating on the core of an optical fiber. The sensing relies on changes in evanescent wave absorbance in the presence of the analyte. The sensor showed excellent selectivity towards Cu (II) ions over all other metal ions. The sensor was tested with lake and marine water samples to determine unknown concentrations of copper ions and the recovery results were within 90-115%, indicating reasonable accuracy. We further integrated the fiber-optic sensor with a miniaturized hand-held instrumentation platform to develop an accurate and field deployable device which can broadly be applicable to determine Cu (II) concentration in a wide range of systems - natural water bodies, soil as well as blood serum. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. A Kinematic Model of Slow Slip Constrained by Tremor-Derived Slip Histories in Cascadia

    Science.gov (United States)

    Schmidt, D. A.; Houston, H.

    2016-12-01

    We explore new ways to constrain the kinematic slip distributions for large slow slip events using constraints from tremor. Our goal is to prescribe one or more slip pulses that propagate across the fault and scale appropriately to satisfy the observations. Recent work (Houston, 2015) inferred a crude representative stress time history at an average point using the tidal stress history, the static stress drop, and the timing of the evolution of tidal sensitivity of tremor over several days of slip. To convert a stress time history into a slip time history, we use simulations to explore the stressing history of a small locked patch due to an approaching rupture front. We assume that the locked patch releases strain through a series of tremor bursts whose activity rate is related to the stressing history. To test whether the functional form of a slip pulse is reasonable, we assume a hypothetical slip time history (Ohnaka pulse) timed with the occurrence of tremor to create a rupture front that propagates along the fault. The duration of the rupture front for a fault patch is constrained by the observed tremor catalog for the 2010 ETS event. The slip amplitude is scaled appropriately to match the observed surface displacements from GPS. Through a forward simulation, we evaluate the ability of the tremor-derived slip history to accurately predict the pattern of surface displacements observed by GPS. We find that the temporal progression of surface displacements are well modeled by a 2-4 day slip pulse, suggesting that some of the longer duration of slip typically found in time-dependent GPS inversions is biased by the temporal smoothing. However, at some locations on the fault, the tremor lingers beyond the passage of the slip pulse. A small percentage (5-10%) of the tremor appears to be activated ahead of the approaching slip pulse, and tremor asperities experience a driving stress on the order of 10 kPa/day. Tremor amplitude, rather than just tremor counts, is needed

  14. Bilateral Hypertrophic Olivary Degeneration and Holmes Tremor without Palatal Tremor: An Unusual Association

    Directory of Open Access Journals (Sweden)

    Carlos Cosentino

    2016-07-01

    Full Text Available Background: Lesions in the Guillain–Mollaret triangle or dentate-rubro-olivary pathway may lead to hypertrophic olivary degeneration (HOD, a secondary trans-synaptic degeneration of the inferior olivary nucleus. HOD is usually associated with palatal tremor and rarely with Holmes tremor. Bilateral HOD is a very unusual condition and very few cases are reported. Case Report: We report here two cases of bilateral HOD after two different vascular lesions located at the decussation of superior cerebellar peduncles, thus impairing both central tegmental tracts and interrupting bilaterally the dentate-rubral-olivary pathway. Interestingly, both developed bilateral Holmes tremor but not palatal tremor. Discussion: Lesions in some of the components in the Guillain–Mollaret triangle may develop Holmes tremor with HOD and without palatal tremor. Magnetic resonance imaging is an invaluable tool in these cases. Better understanding of the pathways in this loop is needed.

  15. [Disappearance of essential neck tremor after pontine base infarction].

    Science.gov (United States)

    Urushitani, M; Inoue, H; Kawamura, K; Kageyama, T; Fujisawa, M; Nishinaka, K; Udaka, F; Kameyama, M

    1996-08-01

    Mechanism of essential tremor remains unknown. Central oscillators, postulated in thalamus, inferior olive, and spinal cord are thought to be important to form rhythmicity, and finally to stimulate spinal or medullary motor cells, leading trembling muscle contraction, tremor. Among several subtypes of essential familial tremor, including hand tremor, neck tremor, and voice tremor, essential neck tremor is a common disorder, and its pathophysiology seems different from that of typical essential hand tremor, since patients with essential hand tremor are responsive to beta blocker, whereas those with neck tremor are usually not. We experienced a 41-year-old left handed woman with essential neck tremor in whom neck titubation disappeared shortly after pontine base infarct. She was our patient in the outpatient clinic with the diagnosis of essential neck tremor. The tremor developed when she was teenage, and has been localized in the neck muscles. Alcohol intake had apparently diminished it transiently. Her mother also had the tremor in her neck. She was admitted to our hospital with sudden onset of right-sided limb weakness and speech disturbance. Neurological examination showed right hemiparesis including the ipsilateral face, scanning speech, and cerebellar limb ataxia on the same side. In addition, there was no tremor in her neck. Brain MR imaging revealed a pontine base infarct at the level of middle pons, which was consistent with paramedian artery territory. The hemiparesis and speech disturbance improved almost completely after treatment, and her neck tremor has never occurred in one year follow-up. In our patient, efficacy of alcohol imply that essential neck tremor and hand tremor had same central nervous pathway including central oscillator in common, and descending cortical fibers is seemingly associated with diminishing patient's tremor. Pathophysiology of essential neck tremor was discussed with reviewing previous literature.

  16. Handheld ESPI-speckle interferometer

    DEFF Research Database (Denmark)

    Skov Hansen, René

    2003-01-01

    . The interferometer presented here is a compact version of the set-up, Which is capable of measuring displacements of small objects, having either a specularly reflecting-or a diffusely scattering surface. The small optical set-up together with the use of the popular USB-communication for acquiring the images...... and controlling the phase of the reference wave constitutes a compact "handheld" instrument and eliminates the need for installing extra hardware, such as frame grabber and Digital to Analog converter, in the host computer....

  17. Accentuated Factors of Handheld Computing

    DEFF Research Database (Denmark)

    Andersson, Bo; Henningsson, Stefan

    The recent years of rapid development of mobile technologies creates opportunities for new user-groups in the mobile workforce to take advantage of in-formation systems (IS). However, to apprehend and harness these opportunities for mobile IS it is crucial to fully understand the user group and t......, these two steps develop the framework towards a theoretical contribution as theory for describing handheld computing from a designer’s perspective. Thirteen semi-structured interviews were made and the tentative framework was elaborated and confirmed....

  18. Frictional-faulting model for harmonic tremor before Redoubt Volcano eruptions

    Science.gov (United States)

    Dmitrieva, Ksenia; Hotovec-Ellis, Alicia J.; Prejean, Stephanie G.; Dunham, Eric M.

    2013-01-01

    Seismic unrest, indicative of subsurface magma transport and pressure changes within fluid-filled cracks and conduits, often precedes volcanic eruptions. An intriguing form of volcano seismicity is harmonic tremor, that is, sustained vibrations in the range of 0.5–5 Hz. Many source processes can generate harmonic tremor. Harmonic tremor in the 2009 eruption of Redoubt Volcano, Alaska, has been linked to repeating earthquakes of magnitudes around 0.5–1.5 that occur a few kilometres beneath the vent. Before many explosions in that eruption, these small earthquakes occurred in such rapid succession—up to 30 events per second—that distinct seismic wave arrivals blurred into continuous, high-frequency tremor. Tremor abruptly ceased about 30 s before the explosions. Here we introduce a frictional-faulting model to evaluate the credibility and implications of this tremor mechanism. We find that the fault stressing rates rise to values ten orders of magnitude higher than in typical tectonic settings. At that point, inertial effects stabilize fault sliding and the earthquakes cease. Our model of the Redoubt Volcano observations implies that the onset of volcanic explosions is preceded by active deformation and extreme stressing within a localized region of the volcano conduit, at a depth of several kilometres.

  19. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Triggered creep as a possible mechanism for delayed dynamic triggering of tremor and earthquakes

    Science.gov (United States)

    Shelly, David R.; Peng, Zhigang; Hill, David P.; Aiken, Chastity

    2011-01-01

    The passage of radiating seismic waves generates transient stresses in the Earth's crust that can trigger slip on faults far away from the original earthquake source. The triggered fault slip is detectable in the form of earthquakes and seismic tremor. However, the significance of these triggered events remains controversial, in part because they often occur with some delay, long after the triggering stress has passed. Here we scrutinize the location and timing of tremor on the San Andreas fault between 2001 and 2010 in relation to distant earthquakes. We observe tremor on the San Andreas fault that is initiated by passing seismic waves, yet migrates along the fault at a much slower velocity than the radiating seismic waves. We suggest that the migrating tremor records triggered slow slip of the San Andreas fault as a propagating creep event. We find that the triggered tremor and fault creep can be initiated by distant earthquakes as small as magnitude 5.4 and can persist for several days after the seismic waves have passed. Our observations of prolonged tremor activity provide a clear example of the delayed dynamic triggering of seismic events. Fault creep has been shown to trigger earthquakes, and we therefore suggest that the dynamic triggering of prolonged fault creep could provide a mechanism for the delayed triggering of earthquakes. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  1. Wireless Handhelds to Support Clinical Nursing Practicum

    Science.gov (United States)

    Wu, Cheng-Chih; Lai, Chin-Yuan

    2009-01-01

    This paper reports our implementation and evaluation of a wireless handheld learning environment used to support a clinical nursing practicum course. The learning environment was designed so that nursing students could use handhelds for recording information, organizing ideas, assessing patients, and also for interaction and collaboration with…

  2. 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.

  3. Autosomal dominant cortical tremor, myoclonus and epilepsy.

    Science.gov (United States)

    Striano, Pasquale; Zara, Federico

    2016-09-01

    The term 'cortical tremor' was first introduced by Ikeda and colleagues to indicate a postural and action-induced shivering movement of the hands which mimics essential tremor, but presents with the electrophysiological findings of cortical reflex myoclonus. The association between autosomal dominant cortical tremor, myoclonus and epilepsy (ADCME) was first recognized in Japanese families and is now increasingly reported worldwide, although it is described using different acronyms (BAFME, FAME, FEME, FCTE and others). The disease usually takes a benign course, although drug-resistant focal seizures or slight intellectual disability occur in some cases. Moreover, a worsening of cortical tremor and myoclonus is common in advanced age. Although not yet recognized by the International League Against Epilepsy (ILAE), this is a well-delineated epilepsy syndrome with remarkable features that clearly distinguishes it from other myoclonus epilepsies. Moreover, genetic studies of these families show heterogeneity and different susceptible chromosomal loci have been identified.

  4. Complex Non-volcanic Tremor in Guerrero Mexico Triggered by the 2010 Mw 8.8 Chilean Earthquake

    Science.gov (United States)

    Zigone, D.; Campillo, M.; Husker, A. L.; Kostoglodov, V.; Payero, J. S.; Frank, W.; Shapiro, N. M.; Voisin, C.; Cougoulat, G.; Cotte, N.

    2010-12-01

    In this study we analyze the tremors triggered in Guerrero region (Mexico) by the 2010 magnitude 8.8 Chilean Earthquake using mini-seismic array data from the French-Mexican G-GAP project and broadband data from the Servicio Sismologico Nacional of Mexico. The strong dynamic shaking by the earthquake produced the first observed triggered non-volcanic tremors (NVT) in Mexico so far with at least 3 different types of tremors at different time scales. There was a slow slip event (SSE) occurring at the time of the earthquake, which may have increased the probability of tremor triggering in the region. The first type of observed triggered tremors occurred during the S waves, Love waves and Rayleigh waves as already reported in other subductions zones and continental faults (Miyazawa and Mori, 2005, 2006; Rubinstein et al., 2007; Gomberg et al., 2008; Peng et al, 2009…). The greatest amount of energy and duration accompanies the long-period Rayleigh waves, with smaller bursts during the S and Love waves. For this particular tremor we observed the dispersion of Rayleigh waves in the envelopes of triggered tremors, which indicates a very strong modulation of the source by the passing surface wave. An unexpected short-term tremor occurred approximately one hour later of the arrival of the surface waves on the coastal stations. The NVT has only been previously observed at distances > 100 km inland. It also has a shorter frequency range (3-6 Hz) than other NVT (1-10 Hz) observed in the region. Finally, we observed a significant increase of so-called ambient tremor activity with higher intensity than all triggered NVT during the days after the earthquake. This study adds new types of tremors to the lexicon of triggered NVT observed in the world.

  5. What is This Thing Called Tremor?

    Science.gov (United States)

    Rubin, A. M.; Bostock, M. G.

    2017-12-01

    Tremor has many enigmatic attributes. The LFEs that comprise it have a dearth of large events, implying a characteristic scale. Bostock et al. (2015) found LFE duration beneath Vancouver Island to be nearly independent of magnitude. That duration ( 0.4 s), multiplied by a shear wave speed, defines a length scale far larger than the spatial separation between consecutive but non-colocated detections. If one LFE ruptures multiple brittle patches in a ductile matrix its propagation speed can be slowed to the extent that consecutive events don't overlap, but then why aren't there larger and smaller LFEs with larger and smaller durations? Perhaps there are. Tremor seismograms from Vancouver Island are often saturated with direct arrivals, by which we mean time lags between events shorter than typical event durations. Direct evidence of this, given the small coda amplitude of LFE stacks, is that seismograms at stations many kilometers apart often track each other wiggle for wiggle. We see this behavior over the full range tremor amplitudes, from close to the noise level on a tremor-free day to 10 times larger. If the LFE magnitude-frequency relation is time-independent, this factor of 10 implies that the LFE occurrence rate during loud tremor is 10^2=100 times that during quiet tremor (>250 LFEs per second). We investigate the implications of this by comparing observed seismograms to synthetics made from the superposition of "LFEs" that are Poissonian in time over a range of average rates. We find that provided the LFEs have a characteristic scale (whether exponential or power law), saturation completely obscures the moment-duration scaling of the contributing events; that is, the moment-duration scaling of LFEs may be identical to that of regular earthquakes. Nonetheless, there are subtle differences between our synthetics and real seismograms, remarkably independent of tremor amplitude, that remain to be explained. Foremost among these is a slightly greater affinity of

  6. Optimal digital filtering for tremor suppression.

    Science.gov (United States)

    Gonzalez, J G; Heredia, E A; Rahman, T; Barner, K E; Arce, G R

    2000-05-01

    Remote manually operated tasks such as those found in teleoperation, virtual reality, or joystick-based computer access, require the generation of an intermediate electrical signal which is transmitted to the controlled subsystem (robot arm, virtual environment, or a cursor in a computer screen). When human movements are distorted, for instance, by tremor, performance can be improved by digitally filtering the intermediate signal before it reaches the controlled device. This paper introduces a novel tremor filtering framework in which digital equalizers are optimally designed through pursuit tracking task experiments. Due to inherent properties of the man-machine system, the design of tremor suppression equalizers presents two serious problems: 1) performance criteria leading to optimizations that minimize mean-squared error are not efficient for tremor elimination and 2) movement signals show ill-conditioned autocorrelation matrices, which often result in useless or unstable solutions. To address these problems, a new performance indicator in the context of tremor is introduced, and the optimal equalizer according to this new criterion is developed. Ill-conditioning of the autocorrelation matrix is overcome using a novel method which we call pulled-optimization. Experiments performed with artificially induced vibrations and a subject with Parkinson's disease show significant improvement in performance. Additional results, along with MATLAB source code of the algorithms, and a customizable demo for PC joysticks, are available on the Internet at http:¿tremor-suppression.com.

  7. Psychogenic Tremor: A Video Guide to Its Distinguishing Features

    Directory of Open Access Journals (Sweden)

    Joseph Jankovic

    2014-08-01

    Full Text Available Background: Psychogenic tremor is the most common psychogenic movement disorder. It has characteristic clinical features that can help distinguish it from other tremor disorders. There is no diagnostic gold standard and the diagnosis is based primarily on clinical history and examination. Despite proposed diagnostic criteria, the diagnosis of psychogenic tremor can be challenging. While there are numerous studies evaluating psychogenic tremor in the literature, there are no publications that provide a video/visual guide that demonstrate the clinical characteristics of psychogenic tremor. Educating clinicians about psychogenic tremor will hopefully lead to earlier diagnosis and treatment. Methods: We selected videos from the database at the Parkinson's Disease Center and Movement Disorders Clinic at Baylor College of Medicine that illustrate classic findings supporting the diagnosis of psychogenic tremor.Results: We include 10 clinical vignettes with accompanying videos that highlight characteristic clinical signs of psychogenic tremor including distractibility, variability, entrainability, suggestibility, and coherence.Discussion: Psychogenic tremor should be considered in the differential diagnosis of patients presenting with tremor, particularly if it is of abrupt onset, intermittent, variable and not congruous with organic tremor. The diagnosis of psychogenic tremor, however, should not be simply based on exclusion of organic tremor, such as essential, parkinsonian, or cerebellar tremor, but on positive criteria demonstrating characteristic features. Early recognition and management are critical for good long-term outcome.

  8. Insights into the causal relationship between slow slip and tectonic tremor in Guerrero, Mexico

    Science.gov (United States)

    Villafuerte, Carlos; Cruz-Atienza, Víctor M.

    2017-08-01

    Similar to other subduction zones, tectonic tremors (TTs) and slow-slip events (SSEs) take place in the deep segment of the plate interface in Guerrero, Mexico. However, their spatial correlation in this region is not as clear as the episodic tremor and slip observed in Cascadia and Japan. In this study we provide insights into the causal relationship between TTs and SSEs in Guerrero by analyzing the evolution of the deformation fields induced by the long-term 2006 SSE together with new locations of TTs and low-frequency earthquakes (LFEs). Unlike previous studies we find that the SSE slip rate modulates the TT and LFE activity in the whole tremor region. This means that the causal relationship between the SSE and the TT activity directly depends on the stressing rate history of the tremor asperities that is modulated by the surrounding slip rate. We estimated that the frictional strength of the asperities producing tremor downdip in the sweet spot is around 3.2 kPa, which is 2.3 times smaller than the corresponding value updip in the transient zone, partly explaining the overwhelming tremor activity of the sweet spot despite that the slow slip there is smaller. Based on the LFE occurrence-rate history during the interlong-term SSE period, we determined that the short-term SSEs in Guerrero take place further downdip (about 35 km) than previously estimated, with maximum slip of about 8 mm in the sweet spot. This new model features a continuum of slow slip extending across the entire tremor region of Guerrero.

  9. 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

  10. Kinetic Tremor: Differences Between Smokers and Non-smokers

    OpenAIRE

    Louis, Elan D.

    2006-01-01

    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 ± SD = 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 ...

  11. Video Browsing on Handheld Devices

    Science.gov (United States)

    Hürst, Wolfgang

    Recent improvements in processing power, storage space, and video codec development enable users now to playback video on their handheld devices in a reasonable quality. However, given the form factor restrictions of such a mobile device, screen size still remains a natural limit and - as the term "handheld" implies - always will be a critical resource. This is not only true for video but any data that is processed on such devices. For this reason, developers have come up with new and innovative ways to deal with large documents in such limited scenarios. For example, if you look at the iPhone, innovative techniques such as flicking have been introduced to skim large lists of text (e.g. hundreds of entries in your music collection). Automatically adapting the zoom level to, for example, the width of table cells when double tapping on the screen enables reasonable browsing of web pages that have originally been designed for large, desktop PC sized screens. A multi touch interface allows you to easily zoom in and out of large text documents and images using two fingers. In the next section, we will illustrate that advanced techniques to browse large video files have been developed in the past years, as well. However, if you look at state-of-the-art video players on mobile devices, normally just simple, VCR like controls are supported (at least at the time of this writing) that only allow users to just start, stop, and pause video playback. If supported at all, browsing and navigation functionality is often restricted to simple skipping of chapters via two single buttons for backward and forward navigation and a small and thus not very sensitive timeline slider.

  12. Migrating tremors illuminate complex deformation beneath the seismogenic San Andreas fault.

    Science.gov (United States)

    Shelly, David R

    2010-02-04

    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.

  13. Intention tremor after head injury

    International Nuclear Information System (INIS)

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

    1989-01-01

    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 ≤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)

  14. Source mechanism of volcanic tremor

    Energy Technology Data Exchange (ETDEWEB)

    Ferrick, M.G.; Qamar, A.; St. Lawrence, W.F.

    1982-10-10

    Low-frequency (<10 Hz) volcanic earthquakes originate at a wide range of depths and occur before, during, and after magmatic eruptions. The characteristics of these earthquakes suggest that they are not typical tectonic events. Physically analogous processes occur in hydraulic fracturing of rock formations, low-frequency icequakes in temperate glaciers, and autoresonance in hydroelectric power stations. We propose that unsteady fluid flow in volcanic conduits is the common source mechanism of low-frequency volcanic earthquakes (tremor). The fluid dynamic source mechanism explains low-frequency earthquakes of arbitrary duration, magnitude, and depth of origin, as unsteady flow is independent of physical properties of the fluid and conduit. Fluid transients occur in both low-viscosity gases and high-viscosity liquids. A fluid transient analysis can be formulated as generally as is warranted by knowledge of the composition and physical properties of the fluid, material properties, geometry and roughness of the conduit, and boundary conditions. To demonstrate the analytical potential of the fluid dynamic theory, we consider a single-phase fluid, a melt of Mount Hood andesite at 1250/sup 0/C, in which significant pressure and velocity variations occur only in the longitudinal direction. Further simplification of the conservation of mass and momentum equations presents an eigenvalue problem that is solved to determine the natural frequencies and associated damping of flow and pressure oscillations.

  15. Towards Robot-Assisted Retinal Vein Cannulation: A Motorized Force-Sensing Microneedle Integrated with a Handheld Micromanipulator †.

    Science.gov (United States)

    Gonenc, Berk; Chae, Jeremy; Gehlbach, Peter; Taylor, Russell H; Iordachita, Iulian

    2017-09-23

    Retinal vein cannulation is a technically demanding surgical procedure where therapeutic agents are injected into the retinal veins to treat occlusions. The clinical feasibility of this approach has been largely limited by the technical challenges associated with performing the procedure. Among the challenges to successful vein cannulation are identifying the moment of venous puncture, achieving cannulation of the micro-vessel, and maintaining cannulation throughout drug delivery. Recent advances in medical robotics and sensing of tool-tissue interaction forces have the potential to address each of these challenges as well as to prevent tissue trauma, minimize complications, diminish surgeon effort, and ultimately promote successful retinal vein cannulation. In this paper, we develop an assistive system combining a handheld micromanipulator, called "Micron", with a force-sensing microneedle. Using this system, we examine two distinct methods of precisely detecting the instant of venous puncture. This is based on measured tool-tissue interaction forces and also the tracked position of the needle tip. In addition to the existing tremor canceling function of Micron, a new control method is implemented to actively compensate unintended movements of the operator, and to keep the cannulation device securely inside the vein following cannulation. To demonstrate the capabilities and performance of our uniquely upgraded system, we present a multi-user artificial phantom study with subjects from three different surgical skill levels. Results show that our puncture detection algorithm, when combined with the active positive holding feature enables sustained cannulation which is most evident in smaller veins. Notable is that the active holding function significantly attenuates tool motion in the vein, thereby reduces the trauma during cannulation.

  16. Towards Robot-Assisted Retinal Vein Cannulation: A Motorized Force-Sensing Microneedle Integrated with a Handheld Micromanipulator †

    Science.gov (United States)

    Gonenc, Berk; Chae, Jeremy; Gehlbach, Peter; Taylor, Russell H.; Iordachita, Iulian

    2017-01-01

    Retinal vein cannulation is a technically demanding surgical procedure where therapeutic agents are injected into the retinal veins to treat occlusions. The clinical feasibility of this approach has been largely limited by the technical challenges associated with performing the procedure. Among the challenges to successful vein cannulation are identifying the moment of venous puncture, achieving cannulation of the micro-vessel, and maintaining cannulation throughout drug delivery. Recent advances in medical robotics and sensing of tool-tissue interaction forces have the potential to address each of these challenges as well as to prevent tissue trauma, minimize complications, diminish surgeon effort, and ultimately promote successful retinal vein cannulation. In this paper, we develop an assistive system combining a handheld micromanipulator, called “Micron”, with a force-sensing microneedle. Using this system, we examine two distinct methods of precisely detecting the instant of venous puncture. This is based on measured tool-tissue interaction forces and also the tracked position of the needle tip. In addition to the existing tremor canceling function of Micron, a new control method is implemented to actively compensate unintended movements of the operator, and to keep the cannulation device securely inside the vein following cannulation. To demonstrate the capabilities and performance of our uniquely upgraded system, we present a multi-user artificial phantom study with subjects from three different surgical skill levels. Results show that our puncture detection algorithm, when combined with the active positive holding feature enables sustained cannulation which is most evident in smaller veins. Notable is that the active holding function significantly attenuates tool motion in the vein, thereby reduces the trauma during cannulation. PMID:28946634

  17. Improving car passengers' comfort and experience by supporting the use of handheld devices.

    Science.gov (United States)

    van Veen, S A T; Hiemstra-van Mastrigt, S; Kamp, I; Vink, P

    2014-01-01

    There is a demand for interiors to support other activities in a car than controlling the vehicle. Currently, this is the case for the car passengers and--in the future--autonomous driving cars will also facilitate drivers to perform other activities. One of these activities is working with handheld devices. Previous research shows that people experience problems when using handheld devices in a moving vehicle and the use of handheld devices generally causes unwanted neck flexion [Young et al. 2012; Sin and Zu 2011; Gold et al.2011]. In this study, armrests are designed to support the arms when using handheld devices in a driving car in order to decrease neck flexion. Neck flexion was measured by attaching markers on the C7 and tragus. Discomfort was indicated on a body map on a scale 1-10. User experience was evaluated in a semi-structured interview. Neck flexion is significantly decreased by the support of the armrests and approaches a neutral position. Furthermore, overall comfort and comfort in the neck region specifically are significantly increased. Subjects appreciate the body posture facilitated by the armrests and 9 out of 10 prefer using handheld devices with the armrests compared to using handheld devices without the armrests. More efforts are needed to develop the mock-up into an established product, but the angles and dimensions presented in this study could serve as guidelines.

  18. Ground-motion prediction from tremor

    Science.gov (United States)

    Baltay, Annemarie S.; Beroza, Gregory C.

    2013-01-01

    The widespread occurrence of tremor, coupled with its frequency content and location, provides an exceptional opportunity to test and improve strong ground-motion attenuation relations for subduction zones. We characterize the amplitude of thousands of individual 5 min tremor events in Cascadia during three episodic tremor and slip events to constrain the distance decay of peak ground acceleration (PGA) and peak ground velocity (PGV). We determine the anelastic attenuation parameter for ground-motion prediction equations (GMPEs) to a distance of 150 km, which is sufficient to place important constraints on ground-motion decay. Tremor PGA and PGV show a distance decay that is similar to subduction-zone-specific GMPEs developed from both data and simulations; however, the massive amount of data present in the tremor observations should allow us to refine distance-amplitude attenuation relationships for use in hazard maps, and to search for regional variations and intrasubduction zone differences in ground-motion attenuation.

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

    Science.gov (United States)

    ... Request that your meat be cut in the kitchen before being served. Consider ordering finger foods to ... Tremor IETF Accepting Proposals for Grants Relevant to Essential Tremor IETF Champion Home About the IETF Volunteer ...

  20. Essential Tremor vs. Parkinson's Disease: How Do They Differ?

    Science.gov (United States)

    Essential Tremor (ET) ET vs Parkinson’s disease How do they differ? The characteristics listed in the table below can help differentiate between parkinsonian and essential tremor, but a medical professional should be consulted for ...

  1. Peripheral beta-adrenergic blockade treatment of parkinsonian tremor.

    Science.gov (United States)

    Foster, N L; Newman, R P; LeWitt, P A; Gillespie, M M; Larsen, T A; Chase, T N

    1984-10-01

    The effect of nadolol, a peripherally acting beta-adrenergic blocker, on resting, postural, and intention tremor was examined in 8 patients with idiopathic Parkinson's disease whose motor symptoms, other than tremor, were well controlled with conventional medications. In a double-blind, placebo-controlled, crossover design, patients received 80 to 320 mg of nadolol for six weeks while continuing their previous therapeutic regimen. Accelerometer readings showed a 34% reduction (p less than 0.025) in tremor distance, but no change in tremor frequency, during nadolol therapy. Maximum benefit was achieved with a dose of 240 mg, when resting tremor improved 54%, postural tremor 32%, and intention tremor 54%. Physician ratings and patient reports supported the accelerometer results. Nadolol appears to be a safe, effective adjunct to current dopaminergic and anticholinergic therapy for severe tremor in Parkinson's disease.

  2. Handheld Microfluidic Blood Ananlyzer, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nanohmics proposes to develop a handheld blood analyzer for micro- and hypo-gravity missions. The prototype instrument will combine impedance analysis with optical...

  3. Augmented Reality Simulations on Handheld Computers

    Science.gov (United States)

    Squire, Kurt; Klopfer, Eric

    2007-01-01

    Advancements in handheld computing, particularly its portability, social interactivity, context sensitivity, connectivity, and individuality, open new opportunities for immersive learning environments. This article articulates the pedagogical potential of augmented reality simulations in environmental engineering education by immersing students in…

  4. Handheld CAT Video Game, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project is to design, develop and fabricate a handheld video game console for astronauts during long space flight. This portable hardware runs...

  5. Tremor pattern differentiates drug-induced resting tremor from Parkinson disease.

    Science.gov (United States)

    Nisticò, R; Fratto, A; Vescio, B; Arabia, G; Sciacca, G; Morelli, M; Labate, A; Salsone, M; Novellino, F; Nicoletti, A; Petralia, A; Gambardella, A; Zappia, M; Quattrone, A

    2016-04-01

    DAT-SPECT, is a well-established procedure for distinguishing drug-induced parkinsonism from Parkinson's disease (PD). We investigated the usefulness of blink reflex recovery cycle (BRrc) and of electromyographic parameters of resting tremor for the differentiation of patients with drug-induced parkinsonism with resting tremor (rDIP) from those with resting tremor due to PD. This was a cross-sectional study. In 16 patients with rDIP and 18 patients with PD we analysed electrophysiological parameters (amplitude, duration, burst and pattern) of resting tremor. BRrc at interstimulus intervals (ISI) of 100, 150, 200, 300, 400, 500 and 750 msec was also analysed in patients with rDIP, patients with PD and healthy controls. All patients and controls underwent DAT-SPECT. Rest tremor amplitude was higher in PD patients than in rDIP patients (p tremor showed a synchronous pattern in all patients with rDIP, whereas it had an alternating pattern in all PD patients (p tremor can be considered a useful investigation for differentiating rDIP from PD. Copyright © 2016. Published by Elsevier Ltd.

  6. 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.

  7. Abnormal 201Tl limb scan due to unilateral tremor

    International Nuclear Information System (INIS)

    Simons, M.; Schelstraete, K.; Bratzlavsky, M.

    1982-01-01

    A abnormal intra- and interextremity distribution pattern on 201 Tl was observed on the limb scan of a patient with a unilateral tremor. This is ascribed to the increased blood flow in the muscles responsible for the tremor. The suggestion is made that the existence of tremor should be considered as a possible explanation for unexpected abnormalities on 201 Tl limb scintigrams

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Deep Brain Stimulation for Essential Tremor: Aligning Thalamic and Posterior Subthalamic Targets in 1 Surgical Trajectory.

    Science.gov (United States)

    Bot, Maarten; van Rootselaar, Fleur; Contarino, Maria Fiorella; Odekerken, Vincent; Dijk, Joke; de Bie, Rob; Schuurman, Richard; van den Munckhof, Pepijn

    2017-12-21

    Ventral intermediate nucleus (VIM) deep brain stimulation (DBS) and posterior subthalamic area (PSA) DBS suppress tremor in essential tremor (ET) patients, but it is not clear which target is optimal. Aligning both targets in 1 surgical trajectory would facilitate exploring stimulation of either target in a single patient. To evaluate aligning VIM and PSA in 1 surgical trajectory for DBS in ET. Technical aspects of trajectories, intraoperative stimulation findings, final electrode placement, target used for chronic stimulation, and adverse and beneficial effects were evaluated. In 17 patients representing 33 trajectories, we successfully aligned VIM and PSA targets in 26 trajectories. Trajectory distance between targets averaged 7.2 (range 6-10) mm. In all but 4 aligned trajectories, optimal intraoperative tremor suppression was obtained in the PSA. During follow-up, active electrode contacts were located in PSA in the majority of cases. Overall, successful tremor control was achieved in 69% of patients. Stimulation-induced dysarthria or gait ataxia occurred in, respectively, 56% and 44% of patients. Neither difference in tremor suppression or side effects was noted between aligned and nonaligned leads nor between the different locations of chronic stimulation. Alignment of VIM and PSA for DBS in ET is feasible and enables intraoperative exploration of both targets in 1 trajectory. This facilitates positioning of electrode contacts in both areas, where multiple effective points of stimulation can be found. In the majority of aligned leads, optimal intraoperative and chronic stimulation were located in the PSA. Copyright © 2017 by the Congress of Neurological Surgeons

  10. Ethosuximide for Essential Tremor: An Open-Label Trial

    OpenAIRE

    Gironell, Alexandre; Marin-Lahoz, Juan

    2016-01-01

    Background: T-type calcium channel activation has been postulated to underlie rhythmicity in the olivo-cerebellar system that is implicated in ET. Ethosuximide reduces T-type calcium currents and can suppress tremor in two animal models of ET. We explored the effects of ethosuximide in subjects with ET in an open-label trial using both clinical scales and accelerometric recordings measures. We initially planned to conduct the trial with 15 patients, but due to lack of efficacy and a high inci...

  11. Connectivity derived thalamic segmentation in deep brain stimulation for tremor

    Directory of Open Access Journals (Sweden)

    Harith Akram

    Full Text Available The ventral intermediate nucleus (VIM of the thalamus is an established surgical target for stereotactic ablation and deep brain stimulation (DBS in the treatment of tremor in Parkinson's disease (PD and essential tremor (ET. It is centrally placed on a cerebello-thalamo-cortical network connecting the primary motor cortex, to the dentate nucleus of the contralateral cerebellum through the dentato-rubro-thalamic tract (DRT. The VIM is not readily visible on conventional MR imaging, so identifying the surgical target traditionally involved indirect targeting that relies on atlas-defined coordinates. Unfortunately, this approach does not fully account for individual variability and requires surgery to be performed with the patient awake to allow for intraoperative targeting confirmation. The aim of this study is to identify the VIM and the DRT using probabilistic tractography in patients that will undergo thalamic DBS for tremor. Four male patients with tremor dominant PD and five patients (three female with ET underwent high angular resolution diffusion imaging (HARDI (128 diffusion directions, 1.5 mm isotropic voxels and b value = 1500 preoperatively. Patients received VIM-DBS using an MR image guided and MR image verified approach with indirect targeting. Postoperatively, using parallel Graphical Processing Unit (GPU processing, thalamic areas with the highest diffusion connectivity to the primary motor area (M1, supplementary motor area (SMA, primary sensory area (S1 and contralateral dentate nucleus were identified. Additionally, volume of tissue activation (VTA corresponding to active DBS contacts were modelled. Response to treatment was defined as 40% reduction in the total Fahn-Tolosa-Martin Tremor Rating Score (FTMTRS with DBS-ON, one year from surgery. Three out of nine patients had a suboptimal, long-term response to treatment. The segmented thalamic areas corresponded well to anatomically known counterparts in the ventrolateral

  12. 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

  13. Ambient Tremor, But No Triggered Tremor at the Northern Costa Rica Subduction Zone

    Science.gov (United States)

    Swiecki, Z.; Schwartz, S. Y.

    2010-12-01

    Non-volcanic tremor (NVT) has been found to be triggered during the passage of surface waves from various teleseismic events in locations around the world including Cascadia, Southwest Japan, Taiwan, and California. In this study we examine the northern Costa Rica subduction zone for evidence of triggered tremor. The Nicoya Peninsula segment of the northern Costa Rica margin experiences both slow-slip and tremor and is thus a prime candidate for triggered tremor observations. Eleven teleseismic events with magnitudes (Mw) greater than 8 occurring between 2006 and 2010 were examined using data from both broadband and short period sensors deployed on the Nicoya Peninsula, Costa Rica. Waveforms from several large regional events were also considered. The largest teleseismic and regional events (27 February 2010 Chile, Mw 8.8 and 28 May 2009 Honduras, Mw 7.3) induced peak ground velocities (PGV) at the NIcoya stations of ~2 and 6 mm/s, respectively; larger than PGVs in other locations that have triggered tremor. Many of the earthquakes examined occurred during small episodes of background ambient tremor. In spite of this, no triggered tremor was observed during the passage of seismic waves from any event. This is significant because other studies have demonstrated that NVT is not triggered everywhere by all events above some threshold magnitude, indicating that unique conditions are required for its occurrence. The lack of triggered tremor at the Costa Rica margin can help to better quantify the requisite conditions and triggering mechanisms. An inherent difference between the Costa Rica margin and the other subduction zones where triggered tremor exists is its erosional rather than accretionary nature. Its relatively low sediment supply likely results in a drier, lower pore fluid pressure, stronger and less compliant thrust interface that is less receptive to triggering tremor from external stresses generated by teleseismic or strong local earthquakes. Another

  14. Multiple Resting-State Networks Are Associated With Tremors and Cognitive Features in Essential Tremor.

    Science.gov (United States)

    Fang, Weidong; Chen, Huiyue; Wang, Hansheng; Zhang, Han; Liu, Mengqi; Puneet, Munankami; Lv, Fajin; Cheng, Oumei; Wang, Xuefeng; Lu, Xiurong; Luo, Tianyou

    2015-12-01

    The heterogeneous clinical features of essential tremor indicate that the dysfunctions of this syndrome are not confined to motor networks, but extend to nonmotor networks. Currently, these neural network dysfunctions in essential tremor remain unclear. In this study, independent component analysis of resting-state functional MRI was used to study these neural network mechanisms. Thirty-five essential tremor patients and 35 matched healthy controls with clinical and neuropsychological tests were included, and eight resting-state networks were identified. After considering the structure and head-motion factors and testing the reliability of the selected resting-state networks, we assessed the functional connectivity changes within or between resting-state networks. Finally, image-behavior correlation analysis was performed. Compared to healthy controls, essential tremor patients displayed increased functional connectivity in the sensorimotor and salience networks and decreased functional connectivity in the cerebellum network. Additionally, increased functional network connectivity was observed between anterior and posterior default mode networks, and a decreased functional network connectivity was noted between the cerebellum network and the sensorimotor and posterior default mode networks. Importantly, the functional connectivity changes within and between these resting-state networks were correlated with the tremor severity and total cognitive scores of essential tremor patients. The findings of this study provide the first evidence that functional connectivity changes within and between multiple resting-state networks are associated with tremors and cognitive features of essential tremor, and this work demonstrates a potential approach for identifying the underlying neural network mechanisms of this syndrome. © 2015 International Parkinson and Movement Disorder Society.

  15. 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.

  16. 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.)

  17. Essential Tremor: What We Can Learn from Current Pharmacotherapy

    Directory of Open Access Journals (Sweden)

    William Ondo

    2016-03-01

    Full Text Available Background: The pathophysiology of essential tremor, especially at the cellular level, is poorly understood. Although no drug has been specifically designed to treat essential tremor, several medications improve tremor, and others worsen it. Studying the mechanism of actions of these medications can help our understanding of tremor pathophysiology and contribute to future rational drug design. Methods: We reviewed literature, concentrating on mechanisms of action, of various medications that mitigate tremor. Results: Many medications have multiple mechanisms of actions, making simple correlations difficult. Medications that increase the duration of opening of gamma-aminobutyric acid (GABA-A receptors are most consistently associated with tremor improvement. Interestingly, drugs that increase GABA availability have not been associated with improved tremor. Other mechanisms possibly associated with tremor improvement include antagonism of alpha-2 delta subunits associated with calcium channels, inhibition of carbonic anhydrase, and inhibition of the synaptic vesicle protein 2A. Drugs that block voltage-gaited sodium channels do not affect tremor. The ideal beta-adrenergic blocker requires B2 affinity (non-cardiac selective, has no sympathomimetic properties, does not require membrane stabilization properties, and may benefit from good central nervous system penetration. Discussion: To date, serendipitous observations have provided most of our understanding of tremor cellular physiology. Based on similarities to currently effective drugs or rational approximations and inferences, several currently available agents should be considered for tremor trials.

  18. Essential Tremor: What We Can Learn from Current Pharmacotherapy.

    Science.gov (United States)

    Ondo, William

    2016-01-01

    The pathophysiology of essential tremor, especially at the cellular level, is poorly understood. Although no drug has been specifically designed to treat essential tremor, several medications improve tremor, and others worsen it. Studying the mechanism of actions of these medications can help our understanding of tremor pathophysiology and contribute to future rational drug design. We reviewed literature, concentrating on mechanisms of action, of various medications that mitigate tremor. Many medications have multiple mechanisms of actions, making simple correlations difficult. Medications that increase the duration of opening of gamma-aminobutyric acid (GABA)-A receptors are most consistently associated with tremor improvement. Interestingly, drugs that increase GABA availability have not been associated with improved tremor. Other mechanisms possibly associated with tremor improvement include antagonism of alpha-2 delta subunits associated with calcium channels, inhibition of carbonic anhydrase, and inhibition of the synaptic vesicle protein 2A. Drugs that block voltage-gaited sodium channels do not affect tremor. The ideal beta-adrenergic blocker requires B2 affinity (non-cardiac selective), has no sympathomimetic properties, does not require membrane stabilization properties, and may benefit from good central nervous system penetration. To date, serendipitous observations have provided most of our understanding of tremor cellular physiology. Based on similarities to currently effective drugs or rational approximations and inferences, several currently available agents should be considered for tremor trials.

  19. Treatment of resting tremor by beta-adrenergic blockade.

    Science.gov (United States)

    Foster, N L; Newman, R P; LeWitt, P A; Gillespie, M M; Chase, T N

    1984-10-01

    The effect of nadolol, a peripherally acting beta-adrenergic blocker, on resting tremor was examined in eight patients with idiopathic Parkinson's disease. With the use of a double-blind, placebo-controlled study of crossover design, patients received 80 to 320 mg of nadolol for 6 weeks while continuing their previous treatment regimen. Accelerometer readings showed a progressive reduction in tremor amplitude, but no change in tremor frequency, with increasing nadolol dosage. Maximum benefit was achieved at 240 mg, when resting tremor improved 50% (p less than 0.01). Physician ratings confirmed these findings. The results suggest that response to beta-adrenergic blockade may not be limited to postural or intention tremor and that such agents may not reliably differentiate between the tremor of Parkinson's disease and essential tremor.

  20. The tremorolytic action of beta-adrenoceptor blockers in essential, physiological and isoprenaline-induced tremor is mediated by beta-adrenoceptors located in a deep peripheral compartment.

    Science.gov (United States)

    Abila, B; Wilson, J F; Marshall, R W; Richens, A

    1985-10-01

    The effects of intravenous propranolol 100 micrograms kg-1, sotalol 500 micrograms kg-1, timolol 7.8 micrograms kg-1, atenolol 125 micrograms kg-1 and placebo on essential, physiological and isoprenaline-induced tremor were studied. These beta-adrenoceptor blocker doses produced equal reduction of standing-induced tachycardia in essential tremor patients. Atenolol produced significantly less reduction of essential and isoprenaline-induced tremor than the non-selective drugs, confirming the importance of beta 2-adrenoceptor blockade in these effects. Propranolol and sotalol produced equal maximal inhibition of isoprenaline-induced tremor but propranolol was significantly more effective in reducing essential tremor. The rate of development of the tremorolytic effect was similar in essential, physiological and isoprenaline-induced tremors but all tremor responses developed significantly more slowly than the heart rate responses. It is proposed that these results indicate that the tremorolytic activity of beta-adrenoceptor blockers in essential, physiological and isoprenaline-induced tremor is exerted via the same beta 2-adrenoceptors located in a deep peripheral compartment which is thought to be in the muscle spindles.

  1. 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

  2. Differential effects of alpha-adrenoceptor blockade on essential, physiological and isoprenaline-induced tremor: evidence for a central origin of essential tremor.

    OpenAIRE

    Abila, B; Wilson, J F; Marshall, R W; Richens, A

    1985-01-01

    Intravenous thymoxamine reduced the power of essential tremor but increased that of physiological and isoprenaline-induced tremor. These findings indicate that essential and physiological tremor have dissimilar pathophysiological mechanisms. They also suggest that central adrenergic mechanisms are involved in the pathophysiology of essential tremor and that isoprenaline-induced tremor is not a good model of essential tremor. Furthermore, alpha-adrenoceptor blockers may be a useful therapy for...

  3. Tectonic Tremor analysis with the Taiwan Chelungpu-Fault Drilling Program (TCDP) downhole seismometer array

    Science.gov (United States)

    Lin, Y.; Hillers, G.; Ma, K.; Campillo, M.

    2011-12-01

    We study tectonic tremor activity in the Taichung area, Taiwan, analyzing continuous seismic records from 6 short-period sensors of the TCDP borehole array situated around 1 km depth. The low background noise level facilitates the detection of low-amplitude tectonic tremor and low-frequency earthquake (LFE) waveforms. We apply a hierarchical analysis to first detect transient amplitude increases, and to subsequently verify its tectonic origin, i.e. to associate it with tremor signals. The frequency content of tremor usually exceeds the background noise around 2-8 Hz; hence, in the first step, we use BHS1, BHS4 and BHS7 (top, center, bottom sensor) records to detect amplitude anomalies in this frequency range. We calculate the smoothed spectra of 30 second non-overlapping windows taken daily from 5 night time hours to avoid increased day time amplitudes associated with cultural activities. Amplitude detection is then performed on frequency dependent median values of 5 minute advancing, 10 minute long time windows, yielding a series of threshold dependent increased-energy spectra-envelopes, indicating teleseismic waveforms, potential tremor records, or other transients related to anthropogenic or natural sources. To verify the transients' tectonic origin, potential tremor waveforms detected by the amplitude method are manually picked in the time domain. We apply the Brown et al. (2008) LFE matched filter technique to three-component data from the 6 available sensors. Initial few-second templates are taken from the analyst-picked, minute-long segments, and correlated component-wise with 24-h data. Significantly increased similarity between templates and matched waveform segments is detected using the array-average 7-fold MAD measure. Harvested waveforms associated with this initial `weak' detection are stacked, and the thus created master templates are used in an iterative correlation procedure to arrive at robust LFE detections. The increased similarity of waveforms

  4. Relationship between eruption plume heights and seismic source amplitudes of eruption tremors and explosion events

    Science.gov (United States)

    Mori, A.; Kumagai, H.

    2016-12-01

    It is crucial to analyze and interpret eruption tremors and explosion events for estimating eruption size and understanding eruption phenomena. Kumagai et al. (EPS, 2015) estimated the seismic source amplitudes (As) and cumulative source amplitudes (Is) for eruption tremors and explosion events at Tungurahua, Ecuador, by the amplitude source location (ASL) method based on the assumption of isotropic S-wave radiation in a high-frequency band (5-10 Hz). They found scaling relations between As and Is for eruption tremors and explosion events. However, the universality of these relations is yet to be verified, and the physical meanings of As and Is are not clear. In this study, we analyzed the relations between As and Is for eruption tremors and explosion events at active volcanoes in Japan, and estimated As and Is by the ASL method. We obtained power-law relations between As and Is, in which the powers were different between eruption tremors and explosion events. These relations were consistent with the scaling relations at Tungurahua volcano. Then, we compared As with maximum eruption plume heights (H) during eruption tremors analyzed in this study, and found that H was proportional to 0.21 power of As. This relation is similar to the plume height model based on the physical process of plume rise, which indicates that H is proportional to 0.25 power of volumetric flow rate for plinian eruptions. This suggests that As may correspond to volumetric flow rate. If we assume a seismic source with volume changes and far-field S-wave, As is proportional to the source volume rate. This proportional relation and the plume height model give rise to the relation that H is proportional to 0.25 power of As. These results suggest that we may be able to estimate plume heights in realtime by estimating As during eruptions from seismic observations.

  5. Geomorphological and Geoelectric Techniques for Kwoi's Multiple Tremor Assessment

    Science.gov (United States)

    Dikedi, P. N.

    2017-12-01

    presence of borehole facilities and quarry activities around the region serve as artificial causal factors of these tremors.

  6. Ethosuximide for Essential Tremor: An Open-Label Trial

    Science.gov (United States)

    Gironell, Alexandre; Marin-Lahoz, Juan

    2016-01-01

    Background T-type calcium channel activation has been postulated to underlie rhythmicity in the olivo-cerebellar system that is implicated in ET. Ethosuximide reduces T-type calcium currents and can suppress tremor in two animal models of ET. We explored the effects of ethosuximide in subjects with ET in an open-label trial using both clinical scales and accelerometric recordings measures. We initially planned to conduct the trial with 15 patients, but due to lack of efficacy and a high incidence of adverse effects, the trial was stopped after seven patients had participated. Methods Seven patients diagnosed with ET were included in the study. The ethosuximide dose was 500 mg daily (BID). The main outcome measures were: 1) tremor clinical rating scale (TCRS) score, 2) accelerometric recordings, and 3) self-reported disability scale score. Results Five patients completed the study, and two dropped out due to adverse effects. There were no significant changes in clinical scores in motor task performance (TCRS 1+2), daily living activities (TCRS 3), or in the patients’ subjective assessment (TCRS 4) and global appraisal. There were no differences observed for accelerometry data or disability scale scores. Anxiety, nervousness, headache, and dizziness were reported by two patients while on ethosuximide, causing them to stop the trial. No patient preferred to continue ethosuximide treatment. Discussion The results of our exploratory study suggest that ethosuximide is not an effective treatment for ET. PMID:27625899

  7. Ethosuximide for Essential Tremor: An Open-Label Trial

    Directory of Open Access Journals (Sweden)

    Alexandre Gironell

    2016-07-01

    Full Text Available Background: T-type calcium channel activation has been postulated to underlie rhythmicity in the olivo-cerebellar system that is implicated in ET. Ethosuximide reduces T-type calcium currents and can suppress tremor in two animal models of ET. We explored the effects of ethosuximide in subjects with ET in an open-label trial using both clinical scales and accelerometric recordings measures. We initially planned to conduct the trial with 15 patients, but due to lack of efficacy and a high incidence of adverse effects, the trial was stopped after seven patients had participated. Methods: Seven patients diagnosed with ET were included in the study. The ethosuximide dose was 500 mg daily (BID. The main outcome measures were: 1 tremor clinical rating scale (TCRS score, 2 accelerometric recordings, and 3 self-reported disability scale score. Results: Five patients completed the study, and two dropped out due to adverse effects. There were no significant changes in clinical scores in motor task performance (TCRS 1+2, daily living activities (TCRS 3, or in the patients’ subjective assessment (TCRS 4 and global appraisal. There were no differences observed for accelerometry data or disability scale scores. Anxiety, nervousness, headache, and dizziness were reported by two patients while on ethosuximide, causing them to stop the trial. No patient preferred to continue ethosuximide treatment. Discussion: The results of our exploratory study suggest that ethosuximide is not an effective treatment for ET.

  8. 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

  9. 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

  10. [The use of neuromodulation for the treatment of tremor].

    Science.gov (United States)

    Bendersky, Damián; Ajler, Pablo; Yampolsky, Claudio

    2014-01-01

    Tremor may be a disabling disorder and pharmacologic treatment is the first-line therapy for these patients. Nevertheless, this treatment may lead to a satisfactory tremor reduction in only 50% of patients with essential tremor. Thalamotomy was the treatment of choice for tremor refractory to medical therapy until deep brain stimulation (DBS) of the ventral intermedius nucleus (Vim) of the thalamus has started being used. Nowadays, thalamotomy is rarely performed. This article is a non-systematic review of the indications, results, programming parameters and surgical technique of DBS of the Vim for the treatment of tremor. In spite of the fact that it is possible to achieve similar clinical results using thalamotomy or DBS of the Vim, the former causes more adverse effects than the latter. Furthermore, DBS can be used bilaterally, whereas thalamotomy has a high risk of causing disartria when it is performed in both sides. DBS of the Vim achieved an adequate tremor improvement in several series of patients with tremor caused by essential tremor, Parkinson's disease or multiple sclerosis. Besides the Vim, there are other targets, which are being used by some authors, such as the zona incerta and the prelemniscal radiations. DBS of the Vim is a useful treatment for disabling tremor refractory to medical therapy. It is essential to carry out an accurate patient selection as well as to use a proper surgical technique. The best stereotactic target for tremor is still unknown, although the Vim is the most used one.

  11. Functional MRI for immediate monitoring stereotactic thalamotomy in a patient with essential tremor

    International Nuclear Information System (INIS)

    Hesselmann, Volker; Schaaf, Maike; Krug, Barbara; Lackner, Klaus; Maarouf, Mohammed; Hunsche, Stefan; Sturm, Volker; Lasek, Kathrin; Wedekind, Christoph

    2006-01-01

    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.)

  12. Loss of Balance between Striatal Feedforward Inhibition and Corticostriatal Excitation Leads to Tremor.

    Science.gov (United States)

    Oran, Yael; Bar-Gad, Izhar

    2018-02-14

    Fast-spiking interneurons (FSIs) exert powerful inhibitory control over the striatum and are hypothesized to balance the massive excitatory cortical and thalamic input to this structure. We recorded neuronal activity in the dorsolateral striatum and globus pallidus (GP) concurrently with the detailed movement kinematics of freely behaving female rats before and after selective inhibition of FSI activity using IEM-1460 microinjections. The inhibition led to the appearance of episodic rest tremor in the body part that depended on the somatotopic location of the injection within the striatum. The tremor was accompanied by coherent oscillations in the local field potential (LFP). Individual neuron activity patterns became oscillatory and coherent in the tremor frequency. Striatal neurons, but not GP neurons, displayed additional temporal, nonoscillatory correlations. The subsequent reduction in the corticostriatal input following muscimol injection to the corresponding somatotopic location in the primary motor cortex led to disruption of the tremor and a reduction of the LFP oscillations and individual neuron's phase-locked activity. The breakdown of the normal balance of excitation and inhibition in the striatum has been shown previously to be related to different motor abnormalities. Our results further indicate that the balance between excitatory corticostriatal input and feedforward FSI inhibition is sufficient to break down the striatal decorrelation process and generate oscillations resulting in rest tremor typical of multiple basal ganglia disorders. SIGNIFICANCE STATEMENT Fast-spiking interneurons (FSIs) play a key role in normal striatal processing by exerting powerful inhibitory control over the network. FSI malfunctions have been associated with abnormal processing of information within the striatum that leads to multiple movement disorders. Here, we study the changes in neuronal activity and movement kinematics following selective inhibition of these

  13. 30 CFR 57.12033 - Hand-held electric tools.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hand-held electric tools. 57.12033 Section 57.12033 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Surface and Underground § 57.12033 Hand-held electric tools. Hand-held electric tools shall not be...

  14. 30 CFR 56.12033 - Hand-held electric tools.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hand-held electric tools. 56.12033 Section 56.12033 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL....12033 Hand-held electric tools. Hand-held electric tools shall not be operated at high potential...

  15. Connectivity derived thalamic segmentation in deep brain stimulation for tremor.

    Science.gov (United States)

    Akram, Harith; Dayal, Viswas; Mahlknecht, Philipp; Georgiev, Dejan; Hyam, Jonathan; Foltynie, Thomas; Limousin, Patricia; De Vita, Enrico; Jahanshahi, Marjan; Ashburner, John; Behrens, Tim; Hariz, Marwan; Zrinzo, Ludvic

    2018-01-01

    The ventral intermediate nucleus (VIM) of the thalamus is an established surgical target for stereotactic ablation and deep brain stimulation (DBS) in the treatment of tremor in Parkinson's disease (PD) and essential tremor (ET). It is centrally placed on a cerebello-thalamo-cortical network connecting the primary motor cortex, to the dentate nucleus of the contralateral cerebellum through the dentato-rubro-thalamic tract (DRT). The VIM is not readily visible on conventional MR imaging, so identifying the surgical target traditionally involved indirect targeting that relies on atlas-defined coordinates. Unfortunately, this approach does not fully account for individual variability and requires surgery to be performed with the patient awake to allow for intraoperative targeting confirmation. The aim of this study is to identify the VIM and the DRT using probabilistic tractography in patients that will undergo thalamic DBS for tremor. Four male patients with tremor dominant PD and five patients (three female) with ET underwent high angular resolution diffusion imaging (HARDI) (128 diffusion directions, 1.5 mm isotropic voxels and b value = 1500) preoperatively. Patients received VIM-DBS using an MR image guided and MR image verified approach with indirect targeting. Postoperatively, using parallel Graphical Processing Unit (GPU) processing, thalamic areas with the highest diffusion connectivity to the primary motor area (M1), supplementary motor area (SMA), primary sensory area (S1) and contralateral dentate nucleus were identified. Additionally, volume of tissue activation (VTA) corresponding to active DBS contacts were modelled. Response to treatment was defined as 40% reduction in the total Fahn-Tolosa-Martin Tremor Rating Score (FTMTRS) with DBS-ON, one year from surgery. Three out of nine patients had a suboptimal, long-term response to treatment. The segmented thalamic areas corresponded well to anatomically known counterparts in the ventrolateral (VL

  16. Handheld Computers in Education: An Industry Perspective

    Science.gov (United States)

    van 't Hooft, Mark; Vahey, Philip

    2007-01-01

    Five representatives from the mobile computing industry provide their perspectives on handhelds in education. While some of their ideas differ, they all agree on the importance of staff development, appropriate curriculum development, and teacher support to create the kinds of personalized learning environments that mobile devices make possible.

  17. Handheld spectrometers: the state of the art

    Science.gov (United States)

    Crocombe, Richard A.

    2013-05-01

    "Small" spectrometers fall into three broad classes: small versions of laboratory instruments, providing data, subsequently processed on a PC; dedicated analyzers, providing actionable information to an individual operator; and process analyzers, providing quantitative or semi-quantitative information to a process controller. The emphasis of this paper is on handheld dedicated analyzers. Many spectrometers have historically been large, possible fragile, expensive and complicated to use. The challenge over the last dozen years, as instruments have moved into the field, has been to make spectrometers smaller, affordable, rugged, easy-to-use, but most of all capable of delivering actionable results. Actionable results can dramatically improve the efficiency of a testing process and transform the way business is done. There are several keys to this handheld spectrometer revolution. Consumer electronics has given us powerful mobile platforms, compact batteries, clearly visible displays, new user interfaces, etc., while telecomm has revolutionized miniature optics, sources and detectors. While these technologies enable miniature spectrometers themselves, actionable information has demanded the development of rugged algorithms for material confirmation, unknown identification, mixture analysis and detection of suspicious materials in unknown matrices. These algorithms are far more sophisticated than the `correlation' or `dot-product' methods commonly used in benchtop instruments. Finally, continuing consumer electronics advances now enable many more technologies to be incorporated into handheld spectrometers, including Bluetooth, wireless, WiFi, GPS, cameras and bar code readers, and the continued size shrinkage of spectrometer `engines' leads to the prospect of dual technology or `hyphenated' handheld instruments.

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

    Science.gov (United States)

    Daub, Eric G.; Shelly, David R.; Guyer, Robert 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.

  19. The long-term outcome of orthostatic tremor.

    Science.gov (United States)

    Ganos, Christos; Maugest, Lucie; Apartis, Emmanuelle; Gasca-Salas, Carmen; Cáceres-Redondo, María T; Erro, Roberto; Navalpotro-Gómez, Irene; Batla, Amit; Antelmi, Elena; Degos, Bertrand; Roze, Emmanuel; Welter, Marie-Laure; Mestre, Tiago; Palomar, Francisco J; Isayama, Reina; Chen, Robert; Cordivari, Carla; Mir, Pablo; Lang, Anthony E; Fox, Susan H; Bhatia, Kailash P; Vidailhet, Marie

    2016-02-01

    Orthostatic tremor is a rare condition characterised by high-frequency tremor that appears on standing. Although the essential clinical features of orthostatic tremor are well established, little is known about the natural progression of the disorder. We report the long-term outcome based on the largest multicentre cohort of patients with orthostatic tremor. Clinical information of 68 patients with clinical and electrophysiological diagnosis of orthostatic tremor and a minimum follow-up of 5 years is presented. There was a clear female preponderance (76.5%) with a mean age of onset at 54 years. Median follow-up was 6 years (range 5-25). On diagnosis, 86.8% of patients presented with isolated orthostatic tremor and 13.2% had additional neurological features. At follow-up, seven patients who initially had isolated orthostatic tremor later developed further neurological signs. A total 79.4% of patients reported worsening of orthostatic tremor symptoms. These patients had significantly longer symptom duration than those without reported worsening (median 15.5 vs 10.5 years, respectively; p=0.005). There was no change in orthostatic tremor frequency over time. Structural imaging was largely unremarkable and dopaminergic neuroimaging (DaTSCAN) was normal in 18/19 cases. Pharmacological treatments were disappointing. Two patients were treated surgically and showed improvement. Orthostatic tremor is a progressive disorder with increased disability although tremor frequency is unchanged over time. In most cases, orthostatic tremor represents an isolated syndrome. Drug treatments are unsatisfactory but surgery may hold promise. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. CaV3.1 is a tremor rhythm pacemaker in the inferior olive

    Science.gov (United States)

    Park, Young-Gyun; Park, Hye-Yeon; Lee, C. Justin; Choi, Soonwook; Jo, Seonmi; Choi, Hansol; Kim, Yang-Hann; Shin, Hee-Sup; Llinas, Rodolfo R.; Kim, Daesoo

    2010-01-01

    The rhythmic motor pathway activation by pacemaker neurons or circuits in the brain has been proposed as the mechanism for the timing of motor coordination, and the abnormal potentiation of this mechanism may lead to a pathological tremor. Here, we show that the potentiation of CaV3.1 T-type Ca2+ channels in the inferior olive contributes to the onset of the tremor in a pharmacological model of essential tremor. After administration of harmaline, 4- to 10-Hz synchronous neuronal activities arose from the IO and then propagated to cerebellar motor circuits in wild-type mice, but those rhythmic activities were absent in mice lacking CaV3.1 gene. Intracellular recordings in brain-stem slices revealed that the CaV3.1-deficient inferior olive neurons lacked the subthreshold oscillation of membrane potentials and failed to trigger 4- to 10-Hz rhythmic burst discharges in the presence of harmaline. In addition, the selective knockdown of CaV3.1 gene in the inferior olive by shRNA efficiently suppressed the harmaline-induced tremor in wild-type mice. A mathematical model constructed based on data obtained from patch-clamping experiments indicated that harmaline could efficiently potentiate CaV3.1 channels by changing voltage-dependent responsiveness in the hyperpolarizing direction. Thus, CaV3.1 is a molecular pacemaker substrate for intrinsic neuronal oscillations of inferior olive neurons, and the potentiation of this mechanism can be considered as a pathological cause of essential tremor. PMID:20498062

  1. Local vibration inhibits H-reflex but does not compromise manual dexterity and does not increase tremor.

    Science.gov (United States)

    Budini, Francesco; Laudani, Luca; Bernardini, Sergio; Macaluso, Andrea

    2017-10-01

    The present work aimed at investigating the effects of local vibration on upper limb postural and kinetic tremor, on manual dexterity and on spinal reflex excitability. Previous studies have demonstrated a decrease in spinal reflex excitability and in force fluctuations in the lower limb but an increase in force fluctuation in the upper limbs. As hand steadiness is of vital importance in many daily-based tasks, and local vibration may also be applied in movement disorders, we decided to further explore this phenomenon. Ten healthy volunteers (26±3years) were tested for H reflex, postural and kinetic tremor and manual dexterity through a Purdue test. EMG was recorded from flexor carpi radialis (FCR) and extensor digitorum communis (EDC). Measurements were repeated at baseline, after a control period during which no vibration was delivered and after vibration. Intervention consisted in holding for two minutes a vibrating handle (frequency 75Hz, displacement∼7mm), control consisted in holding for two minutes the same handle powered off. Reflex excitability decreased after vibration whilst postural tremor and manual dexterity were not affected. Peak kinetic tremor frequency increased from baseline to control measurements (P=0.002). Co-activation EDC/FCR increased from control to vibration (P=0.021). These results show that two minutes local vibration lead to a decrease in spinal excitability, did not compromise manual dexterity and did not increase tremor; however, in contrast with expectations, tremor did not decrease. It is suggested that vibration activated several mechanisms with opposite effects, which resulted in a neutral outcome on postural and kinetic tremor. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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

  3. Precursory tremor of the Askja Caldera landslide, July 2014 - seismic signal analysis and numerical modelling

    Science.gov (United States)

    Lipovsky, B. P.; Schöpa, A.; Chao, W. A.; Hovius, N.; White, R. S.; Green, R. G.

    2017-12-01

    Seismic records can contain valuable information about triggers and precursors of slope failures that might become useful for early-warning purposes. We investigated the seismic data of 52 stations from the University of Cambridge, UK, with respect to the tremor signals preceding a 20-80x106 m3 landslide at the Askja caldera in the Icelandic highlands on 21 July 2014. The landslide created a tsunami in the caldera lake, which inundated the shore up to 60 m high reaching famous tourist spots. This shows the high hazard potential of the site that motivated this study. About 30 min before the landslide, the seismic ground velocities >1 Hz of stations up to 30 km away from the landslide source area started to increase and the tremor signal reached up to three times the background noise level about 7 min before the landslide. In the spectral domain, the tremor is visible as a continuous, harmonic signal with a fundamental frequency of 2.5 Hz and overtones at 5 and 7.5 Hz. About 10 min before the landslide, the activated frequency bands changed their spectral content and up and down gliding is observed contemporaneously. The tremor signal ceases about 5 min before the high-energy failure of the landslide. We interpret the harmonic tremor before the landslide as stick-slip motion on fault patches at the boundaries of the landslide mass. Individual stick-slip events cannot be distinguished in the seismic data and thus have already merged into continuous tremor as they occur very close in time. As up and down gliding of the frequency bands occurs at the same time we favour an explanation where several fault patches are active simultaneously. One patch might accelerate and create up gliding signals and another patch might decelerate and create down gliding. We matched synthetic seismograms produced by numerical simulations of stick-slip movement and the seismic observations. The results show that a patch with a radius of 45 m and a realistic landslide thickness of 30 m can

  4. Insights into Pathophysiology from Medication-induced Tremor

    Directory of Open Access Journals (Sweden)

    John C. Morgan

    2017-10-01

    Full Text Available Background: Medication-induced tremor (MIT is common in clinical practice and there are many medications/drugs that can cause or exacerbate tremors. MIT typically occurs by enhancement of physiological tremor (EPT, but not all drugs cause tremor in this way. In this manuscript, we review how some common examples of MIT have informed us about the pathophysiology of tremor.Methods: We performed a PubMed literature search for published articles dealing with MIT and attempted to identify articles that especially dealt with the medication’s mechanism of inducing tremor.Results: There is a paucity of literature that deals with the mechanisms of MIT, with most manuscripts only describing the frequency and clinical settings where MIT is observed. That being said, MIT emanates from multiple mechanisms depending on the drug and it often takes an individualized approach to manage MIT in a given patient.Discussion: MIT has provided some insight into the mechanisms of tremors we see in clinical practice. The exact mechanism of MIT is unknown for most medications that cause tremor, but it is assumed that in most cases physiological tremor is influenced by these medications. Some medications (epinephrine that cause EPT likely lead to tremor by peripheral mechanisms in the muscle (β-adrenergic agonists, but others may influence the central component (amitriptyline. Other drugs can cause tremor, presumably by blockade of dopamine receptors in the basal ganglia (dopamine-blocking agents, by secondary effects such as causing hyperthyroidism (amiodarone, or by other mechanisms. We will attempt to discuss what is known and unknown about the pathophysiology of the most common MITs.

  5. Scaling analysis of the effects of load on hand tremor movements in essential tremor

    Science.gov (United States)

    Blesić, S.; Stratimirović, Dj.; Milošević, S.; Marić, J.; Kostić, V.; Ljubisavljević, M.

    2011-05-01

    In this paper we have used the Wavelet Transform (WT) and the Detrended Fluctuation Analysis (DFA) methods to analyze hand tremor movements in essential tremor (ET), in two different recording conditions (before and after the addition of wrist-cuff load). We have analyzed the time series comprised of peak-to-peak (PtP) intervals, extracted from regions around the first three main frequency components of the power spectra (PwS) of the recorded tremors, in order to substantiate results related to the effects of load on ET, to distinguish between multiple sources of ET, and to separate the influence of peripheral factors on ET. Our results show that, in ET, the dynamical characteristics, that is, values of respective scaling exponents, of the main frequency component of recorded tremors change after the addition of load. Our results also show that in all the observed cases the scaling behavior of the calculated functions changes as well-the calculated WT scalegrams and DFA functions display a shift in the position of the crossover when the load is added. We conclude that the difference in behavior of the WT and DFA functions between different conditions in ET could be associated with the expected pathology in ET, or with some additional mechanism that controls movements in ET patients, and causes the observed changes in scaling behavior.

  6. Complex evolution of transient slip derived from precise tremor locations in western Shikoku, Japan

    Science.gov (United States)

    Shelly, David R.; Beroza, Gregory C.; Ide, Satoshi

    2007-10-01

    Transient slip events, which occur more slowly than traditional earthquakes, are increasingly being recognized as important components of strain release on faults and may substantially impact the earthquake cycle. Surface-based geodetic instruments provide estimates of the overall slip distribution in larger transients but are unable to capture the detailed evolution of such slip, either in time or in space. Accompanying some of these slip transients is a relatively weak, extended duration seismic signal, known as nonvolcanic tremor, which has recently been shown to be generated by a sequence of shear failures occurring as part of the slip event. By precisely locating the tremor, we can track some features of slip evolution with unprecedented resolution. Here, we analyze two weeklong episodes of tremor and slow slip in western Shikoku, Japan. We find that these slip transients do not evolve in a smooth and steady fashion but contain numerous subevents of smaller size and shorter duration. In addition to along-strike migration rates of ˜10 km/d observed previously, much faster migration also occurs, usually in the slab dip direction, at rates of 25-150 km/h over distances of up to ˜20 km. We observe such migration episodes in both the updip and downdip directions. These episodes may be most common on certain portions of the plate boundary that generate strong tremor in intermittent bursts. The surrounding regions of the fault may slip more continuously, driving these stronger patches to repeated failures. Tremor activity has a strong tidal periodicity, possibly reflecting the modulation of slow slip velocity by tidal stresses.

  7. The complex evolution of transient slip revealed by precise tremor locations in western Shikoku, Japan

    Science.gov (United States)

    Shelly, D. R.; Beroza, G. C.; Ide, S.

    2007-12-01

    Transient slow slip events are increasingly being recognized as important components of strain release on faults and may substantially impact the earthquake cycle. Surface-based geodetic instruments provide estimates of the overall slip distribution in larger transients but are unable to capture the detailed evolution of such slip, either in time or space. Accompanying some of these slip transients is a relatively weak, extended duration seismic signal, known as non-volcanic tremor, which has recently been shown to be generated by a sequence of shear failures occurring as part of the slip event. By precisely locating the tremor, we can track some features of slip evolution with unprecedented resolution. Here, we analyze two weeklong episodes of tremor and slow slip in western Shikoku, Japan. We find that these slip transients do not evolve in a smooth and steady fashion but contain numerous sub-events of smaller size and shorter duration. In addition to along-strike migration rates of about 10 km/day observed previously, much faster migration also occurs, usually in the slab dip direction, at rates of 25-150 km/hour over distances of up to 20 km. We observe such migration episodes in both the up-dip and down-dip directions. These episodes may be most common on certain portions of the plate boundary that generate strong tremor in intermittent bursts. The surrounding regions of the fault may slip more continuously, driving these stronger patches to repeated failures. Tremor activity has a strong tidal periodicity, possibly reflecting the modulation of slow slip velocity by tidal stresses.

  8. Correlation between deep fluids, tremor and creep along the central San Andreas fault.

    Science.gov (United States)

    Becken, Michael; Ritter, Oliver; Bedrosian, Paul A; Weckmann, Ute

    2011-11-30

    The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of Parkfield. Non-volcanic tremor from lower-crustal and upper-mantle depths is most pronounced about thirty kilometres southeast of Parkfield and is thought to be associated with high pore-fluid pressures at depth. Here we present geophysical evidence of fluids migrating into the creeping section of the San Andreas fault that seem to originate in the region of the uppermost mantle that also stimulates tremor, and evidence that along-strike variations in tremor activity and amplitude are related to strength variations in the lower crust and upper mantle. Interconnected fluids can explain a deep zone of anomalously low electrical resistivity that has been imaged by magnetotelluric data southwest of the Parkfield-Cholame segment. Near Cholame, where fluids seem to be trapped below a high-resistivity cap, tremor concentrates adjacent to the inferred fluids within a mechanically strong zone of high resistivity. By contrast, subvertical zones of low resistivity breach the entire crust near the drill hole of the San Andreas Fault Observatory at Depth, northwest of Parkfield, and imply pathways for deep fluids into the eastern fault block, coincident with a mechanically weak crust and the lower tremor amplitudes in the lower crust. Fluid influx to the fault system is consistent with hypotheses of fault-weakening high fluid pressures in the brittle crust.

  9. Striations, duration, migration and tidal response in deep tremor.

    Science.gov (United States)

    Ide, Satoshi

    2010-07-15

    Deep tremor in subduction zones is thought to be caused by small repeating shear slip events on the plate interface with significant slow components. It occurs at a depth of about 30 kilometres and provides valuable information on deep plate motion and shallow stress accumulation on the fault plane of megathrust earthquakes. Tremor has been suggested to repeat at a regular interval, migrate at various velocities and be modulated by tidal stress. Here I show that some time-invariant interface property controls tremor behaviour, using precise location of tremor sources with event duration in western Shikoku in the Nankai subduction zone, Japan. In areas where tremor duration is short, tremor is more strongly affected by tidal stress and migration is inhibited. Where tremor lasts longer, diffusive migration occurs with a constant diffusivity of 10(4) m(2) s(-1). The control property may be the ratio of brittle to ductile areas, perhaps determined by the influence of mantle wedge serpentinization on the plate interface. The spatial variation of the controlling property seems to be characterized by striations in tremor source distribution, which follows either the current or previous plate subduction directions. This suggests that the striations and corresponding interface properties are formed through the subduction of inhomogeneous structure, such as seamounts, for periods as long as ten million years.

  10. Linear modeling of possible mechanisms for parkinson tremor generation

    NARCIS (Netherlands)

    Lohnberg, P.

    1978-01-01

    The power of Parkinson tremor is expressed in terms of possibly changed frequency response functions between relevant variables in the neuromuscular system. The derivation starts out from a linear loopless equivalent model of mechanisms for general tremor generation. Hypothetical changes in this

  11. 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

  12. Estimation of the phase response curve from Parkinsonian tremor.

    Science.gov (United States)

    Saifee, Tabish A; Edwards, Mark J; Kassavetis, Panagiotis; Gilbertson, Tom

    2016-01-01

    Phase response curves (PRCs), characterizing the response of an oscillator to weak external perturbation, have been estimated from a broad range of biological oscillators, including single neurons in vivo. PRC estimates, in turn, provide an intuitive insight into how oscillatory systems become entrained and how they can be desynchronized. Here, we explore the application of PRC theory to the case of Parkinsonian tremor. Initial attempts to establish a causal effect of subthreshold transcranial magnetic stimulation applied to primary motor cortex on the filtered tremor phase were unsuccessful. We explored the possible explanations of this and demonstrate that assumptions made when estimating the PRC in a traditional setting, such as a single neuron, are not arbitrary when applied to the case of tremor PRC estimation. We go on to extract the PRC of Parkinsonian tremor using an iterative method that requires varying the definition of the tremor cycle and estimating the PRC at multiple peristimulus time samples. Justification for this method is supported by estimates of PRC from simulated single neuron data. We provide an approach to estimating confidence limits for tremor PRC and discuss the interpretational caveats introduced by tremor harmonics and the intrinsic variability of the tremor's period. Copyright © 2016 the American Physiological Society.

  13. Fragile X-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Hoem, Gry; Koht, Jeanette

    2017-10-31

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a hereditary neurodegenerative disorder caused by a mutation on the X chromosome. The major signs and symptoms are tremor, ataxia and parkinsonism. Up to one in 2 000 persons over 50 years of age will develop the syndrome. There is reason to believe that too few individuals in Norway undergo testing for this condition.

  14. 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.

  15. A Mobile Mixed-Reality Environment for Children's Storytelling Using a Handheld Projector and a Robot

    Science.gov (United States)

    Sugimoto, Masanori

    2011-01-01

    This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. Pilot studies have been conducted to clarify the…

  16. 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.

  17. 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.

  18. Reversible Holmes' tremor due to spontaneous intracranial hypotension.

    Science.gov (United States)

    Iyer, Rajesh Shankar; Wattamwar, Pandurang; Thomas, Bejoy

    2017-07-27

    Holmes' tremor is a low-frequency hand tremor and has varying amplitude at different phases of motion. It is usually unilateral and does not respond satisfactorily to drugs and thus considered irreversible. Structural lesions in the thalamus and brainstem or cerebellum are usually responsible for Holmes' tremor. We present a 23-year-old woman who presented with unilateral Holmes' tremor. She also had hypersomnolence and headache in the sitting posture. Her brain imaging showed brain sagging and deep brain swelling due to spontaneous intracranial hypotension (SIH). She was managed conservatively and had a total clinical and radiological recovery. The brain sagging with the consequent distortion of the midbrain and diencephalon was responsible for this clinical presentation. SIH may be considered as one of the reversible causes of Holmes' tremor. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Measuring thyroid uptake with hand-held radiation monitors

    International Nuclear Information System (INIS)

    Deschamps, M.

    1987-04-01

    With the use of Iodine 123, 125 and 131 and some compounds of Technetium-99 m, a fraction of the isotopes can be trapped in the thyroid of the technicians. We used the hand-held radiation contamination or survey meters of the nine (9) Nuclear medicine departments we visited to see if they were adequate for the evaluation of thyroid uptake of the users. Measurements on a neck-phanton helped us to determine a minimum detectable activity for each isotope. We were then able to check if the measurements of investigations and action levels were possible. None of the hand-held radiation monitors are completely satisfactory for the measure of thyroid uptake of the user. We discuss a class of equipment capable of measuring radiation emissions at the investigation level. Measurement at the action level is possible with meters having scintillation or proportional probes but none of them permits the discrimination in energy required for a quantitative evaluation of the radioisotopes used

  20. Elbow joint position sense after neuromuscular training with handheld vibration.

    Science.gov (United States)

    Tripp, Brady L; Faust, Donald; Jacobs, Patrick

    2009-01-01

    Clinicians use neuromuscular control exercises to enhance joint position sense (JPS); however, because standardizing such exercises is difficult, validations of their use are limited. To evaluate the acute effects of a neuromuscular training exercise with a handheld vibrating dumbbell on elbow JPS acuity. Crossover study. University athletic training research laboratory. Thirty-one healthy, college-aged volunteers (16 men, 15 women, age = 23 + or - 3 years, height = 173 + or - 8 cm, mass = 76 + or - 14 kg). We measured and trained elbow JPS using an electromagnetic tracking device that provided auditory and visual biofeedback. For JPS testing, participants held a dumbbell and actively identified the target elbow flexion angle (90 degrees ) using the software-generated biofeedback, followed by 3 repositioning trials without feedback. Each neuromuscular training protocol included 3 exercises during which participants held a 2.55-kg dumbbell vibrating at 15, 5, or 0 Hz and used software-generated biofeedback to locate and maintain the target elbow flexion angle for 15 seconds. We calculated absolute (accuracy) and variable (variability) errors using the differences between target and reproduced angles. Training protocols using 15-Hz vibration enhanced accuracy and decreased variability of elbow JPS (P or = .200). Our results suggest these neuromuscular control exercises, which included low-magnitude, low-frequency handheld vibration, may enhance elbow JPS. Future researchers should examine vibration of various durations and frequencies, should include injured participants and functional multijoint and multiplanar measures, and should examine long-term effects of training protocols on JPS and injury.

  1. Characterizing the reflectivity of handheld display devices.

    Science.gov (United States)

    Liu, Peter; Badano, Aldo

    2014-08-01

    With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using methods recommended by the American Association of Physicists in Medicine Task Group 18 (TG18). The authors modified the diffuse reflectance coefficient measurement method outlined in the TG18 report. The authors measured seven handheld display devices (two phones and five tablets) and three workstation displays. The device was attached to a black panel with Velcro. To study the effect of the back surface on the diffuse reflectance coefficient, the authors created Styrofoam masks with different size square openings and placed it in front of the device. Overall, for each display device, measurements of illuminance and reflected luminance on the display screen were taken. The authors measured with no mask, with masks of varying size, and with display-size masks, and calculated the corresponding diffuse reflectance coefficient. For all handhelds, the diffuse reflectance coefficient measured with no back panel were lower than measurements performed with a mask. The authors found an overall increase in reflectivity as the size of the mask decreases. For workstations displays, diffuse reflectance coefficients were higher when no back panel was used, and higher than with masks. In all cases, as luminance increased, illuminance increased, but not at the same rate. Since the size of handheld displays is smaller than that of workstation devices, the TG18 method suffers from a dependency on illumination condition. The authors show that the diffuse reflection coefficients can vary depending on the nature of the back surface of the illuminating box. The variability in the diffuse coefficient can be as large as 20% depending on the size of the mask. For all measurements

  2. Therapeutic effects of arotinolol, a beta-adrenergic blocker, on tremor in MPTP-induced parkinsonian monkeys.

    Science.gov (United States)

    Kuno, S; Mizuta, E; Nishida, J; Takechi, M

    1992-10-01

    The effect of arotinolol, a peripherally acting beta-adrenergic-blocking agent, on postural or kinetic tremor was studied in monkeys with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism. Male cynomolgus monkeys (Macaca fascicularis) were treated with three injections of MPTP hydrochloride (0.3 mg/kg, i.v.) at an interval of 3-4 days, followed by several injections of the same dose every 7 days. Four monkeys with persistent parkinsonian symptoms manifested for greater than 1 year were used. The animals developed mild to moderate degrees of postural or kinetic tremor, and their motor activity was reduced. Arotinolol (20-30 mg/kg, s.c.) significantly suppressed postural tremor in a dose-dependent manner. Propranolol (20-30 mg/kg) was also effective in suppressing the tremor. However, the application of propranolol induced emesis, whereas arotinolol had no adverse effects. These results suggest that arotinolol is a useful adjunct to dopaminergic therapy for tremor in Parkinson's disease.

  3. Differences Between Men and Women in Balance and Tremor in Relation to Plantar Fascia Laxity During the Menstrual Cycle.

    Science.gov (United States)

    Lee, Haneul; Petrofsky, Jerrold

    2018-03-01

      Although much attention has been paid to the effect of estrogen on the knee ligaments, little has been done to examine the ligaments in the foot, such as the plantar fascia, and how they may be altered during the menstrual cycle.   To (1) examine sex differences in plantar fascia thickness and laxity and postural sway and (2) identify any menstrual cycle effects on plantar fascia laxity, postural sway, and neuromuscular tremor between menstruation and the ovulation phase.   Case-control study.   Research laboratory.   Fifteen healthy women (age = 25.9 ± 1.8 years) and 15 healthy men (age = 27.3 ± 2.0 years) volunteered to participate in this study.   We asked participants to perform 8 balance tasks on a force platform while we assessed postural sway and tremor.   Plantar fascia length and thickness unloaded and loaded with body weight were measured via ultrasound. Postural sway and tremor were measured using a force platform.   Plantar fascia length and thickness with pressure were greater in ovulating women compared with men ( P women during menstruation and men. Postural sway and tremor were greater at ovulation than during menstruation ( P men had less sway than ovulating women on the 3 most difficult balance tasks ( P women. Postural sway and tremor in men were the same as in women during menstruation. These findings support the need to be aware of the effect of sex hormones on balance to prevent lower extremity injuries during sport activities.

  4. Differences in postural tremor dynamics with age and neurological disease.

    Science.gov (United States)

    Morrison, Steven; Newell, Karl M; Kavanagh, Justin J

    2017-06-01

    The overlap of dominant tremor frequencies and similarly amplified tremor observed for Parkinson's disease (PD) and essential tremor (ET) means differentiating between these pathologies is often difficult. As tremor exhibits non-linear properties, employing both linear and non-linear analyses may help distinguish between the tremor dynamics of aging, PD and ET. This study was designed to examine postural tremor in healthy older adults, PD and ET using standard linear and non-linear metrics. Hand and finger postural tremor was recorded in 15 healthy older adults (64 ± 6 years), 15 older individuals with PD (63 ± 6 years), and 10 persons with ET (68 ± 7 years). Linear measures of amplitude, frequency, and between-limb coupling (coherence) were performed. Non-linear measures of regularity (ApEn) and coupling (Cross-ApEn) were also used. Additionally, receiver operating characteristic analyses were performed for those measures that were significantly different between all groups. The results revealed that the linear measures only showed significant differences between the healthy adults and ET/PD persons, but no differences between the two neurological groups. Coherence showed higher bilateral coupling for ET but no differences in inter-limb coupling between PD and healthy subjects. However, ApEn values for finger tremor revealed significant differences between all groups, with tremor for ET persons being more regular (lower ApEn) overall. Similarly, Cross-ApEn results also showed differences between all groups, with ET persons showing strongest inter-limb coupling followed by PD and elderly. Overall, our findings point to the diagnostic potential for non-linear measures of coupling and tremor structure as biomarkers for discriminating between ET, PD and healthy persons.

  5. An autocorrelation method to detect low frequency earthquakes within tremor

    Science.gov (United States)

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

    2008-01-01

    Recent studies have shown that deep tremor in the Nankai Trough under western Shikoku consists of a swarm of low frequency earthquakes (LFEs) that occur as slow shear slip on the down-dip extension of the primary seismogenic zone of the plate interface. The similarity of tremor in other locations suggests a similar mechanism, but the absence of cataloged low frequency earthquakes prevents a similar analysis. In this study, we develop a method for identifying LFEs within tremor. The method employs a matched-filter algorithm, similar to the technique used to infer that tremor in parts of Shikoku is comprised of LFEs; however, in this case we do not assume the origin times or locations of any LFEs a priori. We search for LFEs using the running autocorrelation of tremor waveforms for 6 Hi-Net stations in the vicinity of the tremor source. Time lags showing strong similarity in the autocorrelation represent either repeats, or near repeats, of LFEs within the tremor. We test the method on an hour of Hi-Net recordings of tremor and demonstrates that it extracts both known and previously unidentified LFEs. Once identified, we cross correlate waveforms to measure relative arrival times and locate the LFEs. The results are able to explain most of the tremor as a swarm of LFEs and the locations of newly identified events appear to fill a gap in the spatial distribution of known LFEs. This method should allow us to extend the analysis of Shelly et al. (2007a) to parts of the Nankai Trough in Shikoku that have sparse LFE coverage, and may also allow us to extend our analysis to other regions that experience deep tremor, but where LFEs have not yet been identified. Copyright 2008 by the American Geophysical Union.

  6. Volcanic tremor masks its seismogenic source: Results from a study of noneruptive tremor recorded at Mount St. Helens, Washington

    Science.gov (United States)

    Denlinger, Roger P.; Moran, Seth C.

    2014-01-01

    On 2 October 2004, a significant noneruptive tremor episode occurred during the buildup to the 2004–2008 eruption of Mount St. Helens (Washington). This episode was remarkable both because no explosion followed, and because seismicity abruptly stopped following the episode. This sequence motivated us to consider a model for volcanic tremor that does not involve energetic gas release from magma but does involve movement of conduit magma through extension on its way toward the surface. We found that the tremor signal was composed entirely of Love and Rayleigh waves and that its spectral bandwidth increased and decreased with signal amplitude, with broader bandwidth signals containing both higher and lower frequencies. Our modeling results demonstrate that the forces giving rise to this tremor were largely normal to conduit walls, generating hybrid head waves along conduit walls that are coupled to internally reflected waves. Together these form a crucial part of conduit resonance, giving tremor wavefields that are largely a function of waveguide geometry and velocity. We find that the mechanism of tremor generation fundamentally masks the nature of the seismogenic source giving rise to resonance. Thus multiple models can be invoked to explain volcanic tremor, requiring that information from other sources (such as visual observations, geodesy, geology, and gas geochemistry) be used to constrain source models. With concurrent GPS and field data supporting rapid rise of magma, we infer that tremor resulted from drag of nearly solid magma along rough conduit walls as magma was forced toward the surface.

  7. Effects of timolol and atenolol on benign essential tremor: placebo-controlled studies based on quantitative tremor recording.

    Science.gov (United States)

    Dietrichson, P; Espen, E

    1981-08-01

    Two different beta-adrenoreceptor antagonists, atenolol and timolol, were separately compared with a placebo in the suppression of essential tremor. In two-week single-blind placebo-controlled studies with cross-over, timolol (5 mg twice daily) and atenolol (100 mg once daily) produced an equal reduction in sitting heart rate and sitting blood pressure. Timolol was effective in reducing tremor while atenolol failed to reduce tremor amplitude. These results indicate that essential tremor can be reduced but not blocked, by the adrenergic blocker timolol with both beta 1 and beta 2 blocking properties; but not by the relatively selective beta 1 blocking drug atenolol. Possibly, the tremor reduction is medicated by a peripheral effect on beta 2 adrenoreceptors.

  8. Tremor reveals stress shadowing, deep postseismic creep, and depth-dependent slip recurrence on the lower-crustal San Andreas fault near Parkfield

    Science.gov (United States)

    Shelly, David R.; Johnson, Kaj M.

    2011-01-01

    The 2003 magnitude 6.5 San Simeon and the 2004 magnitude 6.0 Parkfield earthquakes induced small, but significant, static stress changes in the lower crust on the central San Andreas fault, where recently detected tectonic tremor sources provide new constraints on deep fault creep processes. We find that these earthquakes affect tremor rates very differently, consistent with their differing transferred static shear stresses. The San Simeon event appears to have cast a "stress shadow" north of Parkfield, where tremor activity was stifled for 3-6 weeks. In contrast, the 2004 Parkfield earthquake dramatically increased tremor activity rates both north and south of Parkfield, allowing us to track deep postseismic slip. Following this event, rates initially increased by up to two orders of magnitude for the relatively shallow tremor sources closest to the rupture, with activity in some sources persisting above background rates for more than a year. We also observe strong depth dependence in tremor recurrence patterns, with shallower sources generally exhibiting larger, less-frequent bursts, possibly signaling a transition toward steady creep with increasing temperature and depth. Copyright 2011 by the American Geophysical Union.

  9. Does eye tremor provide the hyperacuity phenomenon?

    International Nuclear Information System (INIS)

    Zozor, Steeve; Amblard, Pierre-Olivier; Duchêne, Cédric

    2009-01-01

    This paper is devoted to a study of the role of the fluctuations that the eye is subject to, from the point of view of noise-enhanced processing. To this end, a basic model of the retina is considered, namely a regular sampler subject to space and time fluctuations that model the random sampling and the involuntary eye tremor respectively. The filtering that can be done by the photoreceptor is also taken into account and the study focuses on a stochastic model of a natural scene. To quantify the effect of the noise, a coefficient of correlation between the signal acquired by a given photoreceptor and a given point of the scene that the eye is looking at is considered. It is shown both for academic examples and for a more realistic case that the fluctuations which affect the retina can induce noise-enhanced processing effects. The observed effect is then interpreted as a stochastic control of the retina via the random tremor

  10. 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

  11. 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 (pstate condition. The distributions of PSD of tremor were symmetrical, regardless of conditions. Tremor is more evident and typical tremor characteristics, 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. Copyright © 2016. Published by Elsevier B.V.

  12. 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

  13. 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

  14. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western...

  15. 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.

  16. Effects of beta-blockers and nicardipine on oxotremorine-induced tremor in common marmosets.

    Science.gov (United States)

    Mitsuda, M; Nomoto, M; Iwata, S

    1999-10-01

    Effects of beta-blockers (propranolol, arotinolol and nipradilol) and a Ca2+ channel blocker (nicardipine) on oxotremorine-induced tremor were studied in common marmosets. Generalized tremor was elicited by an intraperitoneal administration of 0.25 mg/kg oxotremorine. Intensity of the tremor was classified into 7 degrees, and it was evaluated every 10 min. The total intensity of oxotremorine-induced tremor for each drug was expressed as "points", which were the sum of tremor intensity scores evaluated every 10 min up to 190 min following the administration of oxotremorine. Beta-blockers significantly suppressed the tremor. On the other hand, the Ca2+ channel blocker exacerbated the tremor.

  17. Acute pain management efficiency improves with point-of-care handheld electronic billing system.

    Science.gov (United States)

    Fahy, Brenda G

    2009-02-01

    Technology advances continue to impact patient care and physician workflow. To enable more efficient performance of billing activities, a point-of-care (POC) handheld computer technology replaced a paper-based system on an acute pain management service. Using a handheld personal digital assistant (PDA) and software from MDeverywhere (MDe, MDeverywhere, Long Island, NY), we performed a 1-yr prospective observational study of an anesthesiology acute pain management service billings and collections. Seventeen anesthesiologists providing billable acute pain services were trained and entered their charges on a PDA. Twelve months of data, just before electronic implementation (pre-elec), were compared to a 12-m period after implementation (post-elec). The total charges were 4883 for 890 patients pre-elec and 5368 for 1128 patients post-elec. With adoption of handheld billing, the charge lag days decreased from 29.3 to 7.0 (P billing using PDAs to replace a paper-based billing system improved the collection rate and decreased the number of charge lag days with a positive return on investment. The handheld PDA billing system provided POC support for physicians during their daily clinical (e.g., patient locations, rounding lists) and billing activities, improving workflow.

  18. Median Filtering Methods for Non-volcanic Tremor Detection

    Science.gov (United States)

    Damiao, L. G.; Nadeau, R. M.; Dreger, D. S.; Luna, B.; Zhang, H.

    2016-12-01

    Various properties of median filtering over time and space are used to address challenges posed by the Non-volcanic tremor detection problem. As part of a "Big-Data" effort to characterize the spatial and temporal distribution of ambient tremor throughout the Northern San Andreas Fault system, continuous seismic data from multiple seismic networks with contrasting operational characteristics and distributed over a variety of regions are being used. Automated median filtering methods that are flexible enough to work consistently with these data are required. Tremor is characterized by a low-amplitude, long-duration signal-train whose shape is coherent at multiple stations distributed over a large area. There are no consistent phase arrivals or mechanisms in a given tremor's signal and even the durations and shapes among different tremors vary considerably. A myriad of masquerading noise, anthropogenic and natural-event signals must also be discriminated in order to obtain accurate tremor detections. We present here results of the median methods applied to data from four regions of the San Andreas Fault system in northern California (Geysers Geothermal Field, Napa, Bitterwater and Parkfield) to illustrate the ability of the methods to detect tremor under diverse conditions.

  19. Focal mechanisms and tidal modulation for tectonic tremors in Taiwan

    Science.gov (United States)

    Ide, S.; Yabe, S.; Tai, H. J.; Chen, K. H.

    2015-12-01

    Tectonic tremors in Taiwan have been discovered beneath the southern Central Range, but their hosting structure has been unknown. Here we constrain the focal mechanism of underground deformation related to tremors, using moment tensor inversion in the very low frequency band and tidal stress analysis. Three types of seismic data are used for two analysis steps: detection of tremors and the moment tensor inversion. Short-period seismograms from CWBSN are used for tremor detection. Broadband seismograms from BATS and the TAIGER project are used for both steps. About 1000 tremors were detected using an envelope correlation method in the high frequency band (2-8 Hz). Broadband seismograms are stacked relative to the tremor timing, and inverted for a moment tensor in the low frequency band (0.02-0.05 Hz). The best solution was obtained at 32 km depth, as a double-couple consistent with a low-angle thrust fault dipping to the east-southeast, or a high-angle thrust with a south-southwest strike. Almost all tremors occur when tidal shear stress is positive and normal stress is negative (clamping). Since the clamping stress is high for a high-angle thrust fault, the low-angle thrust fault is more likely to be the fault plane. Tremor rate increases non-linearly with increasing shear stress, suggesting a velocity strengthening friction law. The high tidal sensitivity is inconsistent with horizontal slip motion suggested by previous studies, and normal faults that dominates regional shallow earthquakes. Our results favor thrust slip on a low-angle fault dipping to the east-southeast, consistent with the subduction of the Eurasian plate. The tremor region is characterized by a deep thermal anomaly with decrease normal stress. This region has also experienced enough subduction to produce metamorphic fluids. A large amount of fluid and low vertical stress may explain the high tidal sensitivity.

  20. Hand-held and automated breast ultrasound

    International Nuclear Information System (INIS)

    Bassett, L.W.; Gold, R.H.; Kimme-Smith, C.

    1985-01-01

    The book is a guide for physicians and technologists who use US as an adjunct to mammography; it carefully outlines the pros and cons of US of the breast and its role in the diagnosis of benign and malignant diseases. After an introduction that discusses the philosophy of breast US, the chapters cover the physics of US and instrumentation (both hand-held transducers as well as automated water path scanners), then proceed to a discussion of the normal breast. Sections on benign disorders, malignant lesions, and pitfalls of diagnosis are followed by quiz cases

  1. Relationship between blood harmane and harmine concentrations in familial essential tremor, sporadic essential tremor and controls.

    Science.gov (United States)

    Louis, Elan D; Jiang, Wendy; Gerbin, Marina; Mullaney, Mary M; Zheng, Wei

    2010-12-01

    Harmane, a potent tremor-producing β-carboline alkaloid, may play a role in the etiology of essential tremor (ET). Blood harmane concentrations are elevated in ET cases compared with controls yet the basis for this elevation remains unknown. Decreased metabolic conversion (harmane to harmine) is one possible explanation. Using a sample of >500 individuals, we hypothesized that defective metabolic conversion of harmane to harmine might underlie the observed elevated harmane concentration in ET, and therefore expected to find a higher harmane to harmine ratio in familial ET than in sporadic ET or controls. Blood harmane and harmine concentrations were quantified by high performance liquid chromatography. There were 78 familial ET cases, 187 sporadic ET cases, and 276 controls. Blood harmane and harmine concentrations were correlated with one another (Spearman's r=0.24, p<0.001). The mean (±SD) harmane/harmine ratio=23.4±90.9 (range=0.1-987.5). The harmane/harmine ratio was highest in familial ET (46.7±140.4), intermediate in sporadic ET (28.3±108.1), and lowest in controls (13.5±50.3) (p=0.03). In familial ET cases, there was no association between this ratio and tremor severity (Spearman's r=0.08, p=0.48) or tremor duration (Spearman's r=0.14, p=0.24). The basis for the elevated blood harmane concentration, particularly in familial ET, is not known, although the current findings (highest harmane/harmine ratio in familial ET cases) lends support to the possibility that it could be the result of a genetically-driven reduction in harmane metabolism. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Jaw tremor as a physiological biomarker of bruxism.

    Science.gov (United States)

    Laine, C M; Yavuz, Ş U; D'Amico, J M; Gorassini, M A; Türker, K S; Farina, D

    2015-09-01

    To determine if sleep bruxism is associated with abnormal physiological tremor of the jaw during a visually-guided bite force control task. Healthy participants and patients with sleep bruxism were given visual feedback of their bite force and asked to trace triangular target trajectories (duration=20s, peak force bruxism have abnormal jaw tremor when engaged in a visually-guided bite force task. Measurement of jaw tremor may aid in the detection/evaluation of bruxism. In light of previous literature, our results also suggest that bruxism is marked by abnormal or mishandled peripheral feedback from the teeth. Copyright © 2015. Published by Elsevier Ireland Ltd.

  3. Listening carefully. Unique observations of harmonic tremor at Lascar volcano, Chile

    Energy Technology Data Exchange (ETDEWEB)

    Hellweg, M. [Stuttgart Univ., Stuttgart (Germany). Inst. fuer Geophysik

    1999-06-01

    During the deployment of Proyecto de Investigacion Sismologica de la Cordillera Occidental 94 (PISCO '94) in the Atacama Desert of Northern Chile, a broadband seismic station and a network od three short-period three-component stations were installed around the active volcano Lascar (Chile). The paper analyzes the resulting data set, which include a sequence of harmonic tremor with a fundamental at a about 0.63 Hz and up to 30 overtones lasting 18 h. Power spectra and spectrograms of Lascar's harmonic tremor from the various stations demonstrate that the frequencies recorded cannot be explained as path effects, and must therefore be attributed to mechanisms at or near the source.

  4. Handheld emissions detector (HED): overview and development

    Science.gov (United States)

    Valentino, George J.; Schimmel, David

    2009-05-01

    Nova Engineering, Cincinnati OH, a division of L-3 Communications (L-3 Nova), under the sponsorship of Program Manager Soldier Warrior (PM-SWAR), Fort Belvoir, VA, has developed a Soldier portable, light-weight, hand-held, geolocation sensor and processing system called the Handheld Emissions Detector (HED). The HED is a broadband custom receiver and processor that allows the user to easily sense, direction find, and locate a broad range of emitters in the user's surrounding area. Now in its second design iteration, the HED incorporates a set of COTS components that are complemented with L-3 Nova custom RF, power, digital, and mechanical components, plus custom embedded and application software. The HED user interfaces are designed to provide complex information in a readily-understandable form, thereby providing actionable results for operators. This paper provides, where possible, the top-level characteristics of the HED as well as the rationale behind its design philosophy along with its applications in both DOD and Commercial markets.

  5. Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

    NARCIS (Netherlands)

    Mehra, S.; Werkhoven, P.; Worring, M.

    2006-01-01

    Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

  6. A Cognitive Style Perspective to Handheld Devices: Customization vs. Personalization

    Science.gov (United States)

    Hsieh, Chen-Wei; Chen, Sherry Y.

    2016-01-01

    Handheld devices are widely applied to support open and distributed learning, where students are diverse. On the other hand, customization and personalization can be applied to accommodate students' diversities. However, paucity of research compares the effects of customization and personalization in the context of handheld devices. To this end, a…

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

    Science.gov (United States)

    ... Other specialists, eg in the areas of psychiatry, psychology, rehabilitation, urology, cardiology, and movement disorders neurology, may ... problems), tremors, and other symptoms, and MRI findings. History of FXTAS FXTAS was first described in five ...

  8. Iceberg Harmonic Tremor, Seismometer Data, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Seismometers were placed on a 25 km by 50 km iceberg called C16 in the Ross Sea, Antarctica, to identify the Iceberg harmonic Tremor (IHT) source mechanism and to...

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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...... significantly with higher spiral scores and more positive items. More patients were identified by spiral drawing in all tremor groups. The interrater and intrarater reliability for spirals ranged from 0.7 to 0.8 using intraclass coefficient. A cluster analysis revealed that the questionnaire can be reduced...

  11. Holmes' tremor as a delayed complication of thalamic stroke.

    Science.gov (United States)

    Martins, William Alves; Marrone, Luiz Carlos Porcello; Fussiger, Helena; Vedana, Viviane Maria; Cristovam, Rafael do Amaral; Taietti, Marjorye Z; Marrone, Antonio Carlos Huf

    2016-04-01

    Movement disorders are not commonly associated with stroke. Accordingly, thalamic strokes have rarely been associated with tremor, pseudo-athetosis and dystonic postures. We present a 75-year-old man who developed a disabling tremor 1 year after a posterolateral thalamic stroke. This tremor had low frequency (3-4 Hz), did not disappear on focus and was exacerbated by maintaining a static posture and on target pursuit, which made it very difficult to perform basic functions. MRI demonstrated an old ischemic lesion at the left posterolateral thalamus. Treatment with levodopa led to symptom control. Lesions in the midbrain, cerebellum and thalamus may cause Holmes' tremor. Delayed onset of symptoms is usually seen, sometimes appearing 2 years after the original injury. This may be due to maturation of a complex neuronal network, leading to slow dopaminergic denervation. Further studies are needed to improve our understanding of this unique disconnection syndrome. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Rare association of central pontine myelinolysis with infantile tremor syndrome

    Directory of Open Access Journals (Sweden)

    Kalpana Datta

    2012-01-01

    Full Text Available Central pontine myelinolysis (CPM is an acute demyelination within the central basis pontis. Though exact mechanism is not known it is seen commonly with rapid correction of hyponatremia and also with pontine ischemia or infarction, demyelinating diseases, pontine neoplasm and different metabolic diseases. We report a rare association of CPM in a patient of Infantile Tremor Syndrom (ITS. ITS is a syndrome of tremor, mental and physical retardation, pigmentary changes of hair and skin and anemia in malnourished children. Though first reported in Indian subcontinent many identical cases were reported from around the world. Our case is a 15 month old child with generalized tremor, mild hepatosplenomegaly with features of grade II malnutrition including skin and hair changes. All the signs and symtoms of tremor improved after treatment with the World Health Organization (WHO protocol for protein energy malnutrition (PEM and administration of propranolol without any side effects.

  13. Cortical tremor: a variant of cortical reflex myoclonus.

    Science.gov (United States)

    Ikeda, A; Kakigi, R; Funai, N; Neshige, R; Kuroda, Y; Shibasaki, H

    1990-10-01

    Two patients with action tremor that was thought to originate in the cerebral cortex showed fine shivering-like finger twitching provoked mainly by action and posture. Surface EMG showed relatively rhythmic discharge at a rate of about 9 Hz, which resembled essential tremor. However, electrophysiologic studies revealed giant somatosensory evoked potentials (SEPs) with enhanced long-loop reflex and premovement cortical spike by the jerk-locked averaging method. Treatment with beta-blocker showed no effect, but anticonvulsants such as clonazepam, valproate, and primidone were effective to suppress the tremor and the amplitude of SEPs. We call this involuntary movement "cortical tremor," which is in fact a variant of cortical reflex myoclonus.

  14. Image Quality Characteristics of Handheld Display Devices for Medical Imaging

    Science.gov (United States)

    Yamazaki, Asumi; Liu, Peter; Cheng, Wei-Chung; Badano, Aldo

    2013-01-01

    Handheld devices such as mobile phones and tablet computers have become widespread with thousands of available software applications. Recently, handhelds are being proposed as part of medical imaging solutions, especially in emergency medicine, where immediate consultation is required. However, handheld devices differ significantly from medical workstation displays in terms of display characteristics. Moreover, the characteristics vary significantly among device types. We investigate the image quality characteristics of various handheld devices with respect to luminance response, spatial resolution, spatial noise, and reflectance. We show that the luminance characteristics of the handheld displays are different from those of workstation displays complying with grayscale standard target response suggesting that luminance calibration might be needed. Our results also demonstrate that the spatial characteristics of handhelds can surpass those of medical workstation displays particularly for recent generation devices. While a 5 mega-pixel monochrome workstation display has horizontal and vertical modulation transfer factors of 0.52 and 0.47 at the Nyquist frequency, the handheld displays released after 2011 can have values higher than 0.63 at the respective Nyquist frequencies. The noise power spectra for workstation displays are higher than 1.2×10−5 mm2 at 1 mm−1, while handheld displays have values lower than 3.7×10−6 mm2. Reflectance measurements on some of the handheld displays are consistent with measurements for workstation displays with, in some cases, low specular and diffuse reflectance coefficients. The variability of the characterization results among devices due to the different technological features indicates that image quality varies greatly among handheld display devices. PMID:24236113

  15. Seismic tremors and magma wagging during explosive volcanism.

    Science.gov (United States)

    Jellinek, A Mark; Bercovici, David

    2011-02-24

    Volcanic tremor is a ubiquitous feature of explosive eruptions. This oscillation persists for minutes to weeks and is characterized by a remarkably narrow band of frequencies from about 0.5 Hz to 7 Hz (refs 1-4). Before major eruptions, tremor can occur in concert with increased gas flux and related ground deformation. 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, which explains 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 is often observed.

  16. [Assessment of anti-tremorogenic drugs--nicotine-induced tail-tremor model].

    Science.gov (United States)

    Suemaru, K; Kawasaki, H; Gomita, Y

    1997-06-01

    The repeated administration of nicotine at small doses, which do not produce whole body tremor or convulsion, causes tremor only in the tail (tail-tremor) of rats. The tremor is accompanied by locomotor hyperactivity without rigidity and immobility of the whole body, suggesting that the nicotine-induced tail-tremor model is useful for studying the mechanism underlying tremor associated with movement. The tail-tremor induced by nicotine was suppressed by mecamylamine, a nicotinic antagonist, but not by atropine or scopolamine, muscalinic antagonists. Moreover, the tail-tremor was suppressed by the beta-blockers propranolol and pindolol, as well as the benzodiazepines diazepam and clonazepam. Tremor at rest is observed only in Parkinson's disease, which is improved with anti-muscalinic drugs. Essential tremor is one of the typical tremors connected with movement (postural and kinetic tremor) and is improved with beta-blocker. These findings and results suggest that nicotine-induced tail-tremor is useful for the study of essential tremor in animal models.

  17. Lessons I have learned from my patients: everyday life with primary orthostatic tremor.

    Science.gov (United States)

    Vidailhet, Marie; Roze, Emmanuel; Maugest, Lucie; Gallea, Cécile

    2017-01-01

    Primary orthostatic tremor is a rare disorder that is still under-diagnosed or misdiagnosed. Motor symptoms are fairly characteristics but the real impact on the patient's every day life and quality of life is under-estimated. The "how my patients taught me" format describes the impact on the patients' every day life with their own words, which is rarely done. A 46 year old lady was diagnosed primary orthostatic tremor (POT) based on the cardinal symptoms: feelings of instability, leg tremor and fear of falling in the standing position, improvement with walking and disappearance while sitting, frequency of Tremor in the 13-18Hz range, normal neurological examination. She gives illustrative examples of her disability in every day life activity (shower, public transportation, shopping). She reports how she felt stigmatized by her "invisible disorder". As a consequence, she developed anxiety depression and social phobia. All these troubles are unknown or under recognized by doctors and family. We review the clinical signs of POT that may help to increase the awareness of doctors and improve the diagnosis accuracy, based on the motor symptoms and description of the every day life disability, as reported by the patient. Non-motor symptoms (including somatic concerns, anxiety, depression, and social phobia) should be better considered in POT as they have a major impact on quality of life. Pharmacological treatments (clonazepam, gabapentin) may be helpful but have a limited effect over the years as the patients experience a worsening of their condition. On the long term follow-up, there are still unmet needs in POT, and new therapeutic avenues may be based on the pathophysiology by modulating the cerebello-thalamo-cortical network.

  18. 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.

  19. 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.

  20. Handheld Multi-Gas Meters Assessment Report

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Gustavious [Brigham Young Univ., Provo, UT (United States); Wald-Hopkins, Mark David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Obrey, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Akhadov, Valida Dushdurova [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-27

    Handheld multi-gas meters (MGMs) are equipped with sensors to monitor oxygen (O2) levels and additional sensors to detect the presence of combustible or toxic gases in the environment. This report is limited to operational response-type MGMs that include at least four different sensors. These sensors can vary by type and by the monitored chemical. In real time, the sensors report the concentration of monitored gases in the atmosphere near the MGM. In April 2016 the System Assessment and Validation for Emergency Responders (SAVER) Program conducted an operationally-oriented assessment of MGMs. Five MGMs were assessed by emergency responders. The criteria and scenarios used in this assessment were derived from the results of a focus group of emergency responders with experience in using MGMs. The assessment addressed 16 evaluation criteria in four SAVER categories: Usability, Capability, Maintainability, and Deployability.

  1. Handheld microwave bomb-detecting imaging system

    Science.gov (United States)

    Gorwara, Ashok; Molchanov, Pavlo

    2017-05-01

    Proposed novel imaging technique will provide all weather high-resolution imaging and recognition capability for RF/Microwave signals with good penetration through highly scattered media: fog, snow, dust, smoke, even foliage, camouflage, walls and ground. Image resolution in proposed imaging system is not limited by diffraction and will be determined by processor and sampling frequency. Proposed imaging system can simultaneously cover wide field of view, detect multiple targets and can be multi-frequency, multi-function. Directional antennas in imaging system can be close positioned and installed in cell phone size handheld device, on small aircraft or distributed around protected border or object. Non-scanning monopulse system allows dramatically decrease in transmitting power and at the same time provides increased imaging range by integrating 2-3 orders more signals than regular scanning imaging systems.

  2. Optical links in handheld multimedia devices

    Science.gov (United States)

    van Geffen, S.; Duis, J.; Miller, R.

    2008-04-01

    Ever emerging applications in handheld multimedia devices such as mobile phones, laptop computers, portable video games and digital cameras requiring increased screen resolutions are driving higher aggregate bitrates between host processor and display(s) enabling services such as mobile video conferencing, video on demand and TV broadcasting. Larger displays and smaller phones require complex mechanical 3D hinge configurations striving to combine maximum functionality with compact building volumes. Conventional galvanic interconnections such as Micro-Coax and FPC carrying parallel digital data between host processor and display module may produce Electromagnetic Interference (EMI) and bandwidth limitations caused by small cable size and tight cable bends. To reduce the number of signals through a hinge, the mobile phone industry, organized in the MIPI (Mobile Industry Processor Interface) alliance, is currently defining an electrical interface transmitting serialized digital data at speeds >1Gbps. This interface allows for electrical or optical interconnects. Above 1Gbps optical links may offer a cost effective alternative because of their flexibility, increased bandwidth and immunity to EMI. This paper describes the development of optical links for handheld communication devices. A cable assembly based on a special Plastic Optical Fiber (POF) selected for its mechanical durability is terminated with a small form factor molded lens assembly which interfaces between an 850nm VCSEL transmitter and a receiving device on the printed circuit board of the display module. A statistical approach based on a Lean Design For Six Sigma (LDFSS) roadmap for new product development tries to find an optimum link definition which will be robust and low cost meeting the power consumption requirements appropriate for battery operated systems.

  3. Discrimination of Parkinsonian Tremor From Essential Tremor by Voting Between Different EMG Signal Processing Techniques

    Directory of Open Access Journals (Sweden)

    A Hossen

    2014-06-01

    Full Text Available Parkinson's disease (PD and essential tremor (ET are the two most common disorders that cause involuntary muscle shaking movements, or what is called "tremor”. PD is a neurodegenerative disease caused by the loss of dopamine receptors which control and adjust the movement of the body. On the other hand, ET is a neurological movement disorder which also causes tremors and shaking, but it is not related to dopamine receptor loss; it is simply a tremor. The differential diagnosis between these two disorders is sometimes difficult to make clinically because of the similarities of their symptoms; additionally, the available tests are complex and expensive. Thus, the objective of this paper is to discriminate between these two disorders with simpler, cheaper and easier ways by using electromyography (EMG signal processing techniques. EMG and accelerometer records of 39 patients with PD and 41 with ET were acquired from the Hospital of Kiel University in Germany and divided into a trial group and a test group. Three main techniques were applied: the wavelet-based soft-decision technique, statistical signal characterization (SSC of the spectrum of the signal, and SSC of the amplitude variation of the Hilbert transform. The first technique resulted in a discrimination efficiency of 80% on the trial set and 85% on the test set. The second technique resulted in an efficiency of 90% on the trial set and 82.5% on the test set. The third technique resulted in an 87.5% efficiency on the trial set and 65.5% efficiency on the test set. Lastly, a final vote was done to finalize the discrimination using these three techniques, and as a result of the vote, accuracies of 92.5%, 85.0% and 88.75% were obtained on the trial data, test data and total data, respectively.

  4. LINGO-1 and Neurodegeneration: Pathophysiologic Clues for Essential Tremor?

    Directory of Open Access Journals (Sweden)

    Zhou Zhi-dong

    2012-03-01

    Full Text Available 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.

  5. Correcting for motion artifact in handheld laser speckle images

    Science.gov (United States)

    Lertsakdadet, Ben; Yang, Bruce Y.; Dunn, Cody E.; Ponticorvo, Adrien; Crouzet, Christian; Bernal, Nicole; Durkin, Anthony J.; Choi, Bernard

    2018-03-01

    Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst). The difference between Kbest and Kworst in mounted and handheld setups was 8% and 52%, respectively, thereby reinforcing the need for motion artifact quantification. When using a threshold FM speckle contrast value (KFM) to identify a subset of images with an acceptable level of motion artifact, mounted and handheld LSI measurements of speckle contrast of a flow region (KFLOW) in in vitro flow phantom experiments differed by 8%. Without the use of the FM, mounted and handheld KFLOW values differed by 20%. To further validate our handheld LSI device, we compared mounted and handheld data from an in vivo porcine burn model of superficial and full thickness burns. The speckle contrast within the burn region (KBURN) of the mounted and handheld LSI data differed by burns. Collectively, our results suggest the potential of handheld LSI with an FM as a suitable alternative to mounted LSI, especially in challenging clinical settings with space limitations such as the intensive care unit.

  6. Slab dehydration in Cascadia and its relationship to volcanism, seismicity, and non-volcanic tremor

    Science.gov (United States)

    Delph, J. R.; Levander, A.; Niu, F.

    2017-12-01

    The characteristics of subduction beneath the Pacific Northwest (Cascadia) are variable along strike, leading to the segmentation of Cascadia into 3 general zones: Klamath, Siletzia, and Wrangelia. These zones show marked differences in tremor density, earthquake density, seismicity rates, and the locus and amount of volcanism in the subduction-related volcanic arc. To better understand what controls these variations, we have constructed a 3D shear-wave velocity model of the upper 80 km along the Cascadia margin from the joint inversion of CCP-derived receiver functions and ambient noise surface wave data using 900 temporary and permanent broadband seismic stations. With this model, we can investigate variations in the seismic structure of the downgoing oceanic lithosphere and overlying mantle wedge, the character of the crust-mantle transition beneath the volcanic arc, and local to regional variations in crustal structure. From these results, we infer the presence and distribution of fluids released from the subducting slab and how they affect the seismic structure of the overriding lithosphere. In the Klamath and Wrangelia zones, high seismicity rates in the subducting plate and high tremor density correlate with low shear velocities in the overriding plate's forearc and relatively little arc volcanism. While the cause of tremor is debated, intermediate depth earthquakes are generally thought to be due to metamorphic dehydration reactions resulting from the dewatering of the downgoing slab. Thus, the seismic characteristics of these zones combined with rather sparse arc volcanism may indicate that the slab has largely dewatered by the time it reaches sub-arc depths. Some of the water released during earthquakes (and possibly tremor) may percolate into the overriding plate, leading to slow seismic velocities in the forearc. In contrast, Siletzia shows relatively low seismicity rates and tremor density, with relatively higher shear velocities in the forearc

  7. Time-Reversal Study of the Hemet (CA) Tremor Source

    Science.gov (United States)

    Larmat, C. S.; Johnson, P. A.; Guyer, R. A.

    2010-12-01

    Since its first observation by Nadeau & Dolenc (2005) and Gomberg et al. (2008), tremor along the San Andreas fault system is thought to be a probe into the frictional state of the deep part of the fault (e.g. Shelly et al., 2007). Tremor is associated with slow, otherwise deep, aseismic slip events that may be triggered by faint signals such as passing waves from remote earthquakes or solid Earth tides.Well resolved tremor source location is key to constrain frictional models of the fault. However, tremor source location is challenging because of the high-frequency and highly-scattered nature of tremor signal characterized by the lack of isolated phase arrivals. Time Reversal (TR) methods are emerging as a useful tool for location. The unique requirement is a good velocity model for the different time-reversed phases to arrive coherently onto the source point. We present results of location for a tremor source near the town of Hemet, CA, which was triggered by the 2002 M 7.9 Denali Fault earthquake (Gomberg et al., 2008) and by the 2009 M 6.9 Gulf of California earthquake. We performed TR in a volume model of 88 (N-S) x 70 (W-E) x 60 km (Z) using the full-wave 3D wave-propagation package SPECFEM3D (Komatitsch et al., 2002). The results for the 2009 episode indicate a deep source (at about 22km) which is about 4km SW the fault surface scarp. We perform STA/SLA and correlation analysis in order to have independent confirmation of the Hemet tremor source. We gratefully acknowledge the support of the U. S. Department of Energy through the LANL/LDRD Program for this work.

  8. Deep brain stimulation in uncommon tremor disorders: indications, targets, and programming.

    Science.gov (United States)

    Artusi, Carlo Alberto; Farooqi, Ashar; Romagnolo, Alberto; Marsili, Luca; Balestrino, Roberta; Sokol, Leonard L; Wang, Lily L; Zibetti, Maurizio; Duker, Andrew P; Mandybur, George T; Lopiano, Leonardo; Merola, Aristide

    2018-03-06

    In uncommon tremor disorders, clinical efficacy and optimal anatomical targets for deep brain stimulation (DBS) remain inadequately studied and insufficiently quantified. We performed a systematic review of PubMed.gov and ClinicalTrials.gov. Relevant articles were identified using the following keywords: "tremor", "Holmes tremor", "orthostatic tremor", "multiple sclerosis", "multiple sclerosis tremor", "neuropathy", "neuropathic tremor", "fragile X-associated tremor/ataxia syndrome", and "fragile X." We identified a total of 263 cases treated with DBS for uncommon tremor disorders. Of these, 44 had Holmes tremor (HT), 18 orthostatic tremor (OT), 177 multiple sclerosis (MS)-associated tremor, 14 neuropathy-associated tremor, and 10 fragile X-associated tremor/ataxia syndrome (FXTAS). DBS resulted in favorable, albeit partial, clinical improvements in HT cases receiving Vim-DBS alone or in combination with additional targets. A sustained improvement was reported in OT cases treated with bilateral Vim-DBS, while the two cases treated with unilateral Vim-DBS demonstrated only a transient effect. MS-associated tremor responded to dual-target Vim-/VO-DBS, but the inability to account for the progression of MS-associated disability impeded the assessment of its long-term clinical efficacy. Neuropathy-associated tremor substantially improved with Vim-DBS. In FXTAS patients, while Vim-DBS was effective in improving tremor, equivocal results were observed in those with ataxia. DBS of select targets may represent an effective therapeutic strategy for uncommon tremor disorders, although the level of evidence is currently in its incipient form and based on single cases or limited case series. An international registry is, therefore, warranted to clarify selection criteria, long-term results, and optimal surgical targets.

  9. The occurrence of dystonia in upper-limb multiple sclerosis tremor.

    Science.gov (United States)

    Van der Walt, A; Buzzard, K; Sung, S; Spelman, T; Kolbe, S C; Marriott, M; Butzkueven, H; Evans, A

    2015-12-01

    The pathophysiology of multiple sclerosis (MS) tremor is uncertain with limited phenotypical studies available. To investigate whether dystonia contributes to MS tremor and its severity. MS patients (n = 54) with and without disabling uni- or bilateral upper limb tremor were recruited (39 limbs per group). We rated tremor severity, writing and Archimedes spiral drawing; cerebellar dysfunction (SARA score); the Global Dystonia Scale (GDS) for proximal and distal upper limbs, dystonic posturing, mirror movements, geste antagoniste, and writer's cramp. Geste antagoniste, mirror dystonia, and dystonic posturing were more frequent and severe (p tremor severity in tremor compared to non-tremor patients. A 1-unit increase in distal dystonia predicted a 0.52-Bain unit (95% confidence interval (CI) 0.08-0.97), p = 0.022) increase in tremor severity and a 1-unit (95% CI 0.48-1.6, p = 0.001) increase in drawing scores. A 1-unit increase in proximal dystonia predicted 0.93-Bain unit increase (95% CI 0.45-1.41, p tremor severity and 1.5-units (95% CI 0.62-2.41, p = 0.002) increase in the drawing score. Cerebellar function in the tremor limb and tremor severity was correlated (p tremor suggesting that MS tremor pathophysiology involves cerebello-pallido-thalamo-cortical network dysfunction. © The Author(s), 2015.

  10. Motor and Non-motor Features: Differences between Patients with Isolated Essential Tremor and Patients with Both Essential Tremor and Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Apostolia Ghika

    2015-08-01

    Full Text Available Background: Patients with essential tremor (ET who develop Parkinson’s disease (ET->PD may differ with respect to motor features (MFs and non-motor features (NMFs from patients with isolated ET. Few studies have assessed this issue. Methods: In this retrospective chart review, we analyzed data on MFs and NMFs of 175 patients, including 54 ET->PD and 121 ET, actively followed in the Athens University 1st Neurology Department. Results: Significantly more ET->PD than ET patients reported asymmetric tremor at ET onset (68.5% vs. 14.9%, p<0.001.  Significantly more ET than ET->PD patients had head tremor (43.5% vs. 13.2%, p<0.001 and cerebellar signs (41.3% vs. 9.3%, p<0.001. More ET than ET->PD patients reported hearing impairment (65.3% vs. 28.3%, p<0.001 and restless legs syndrome (34.8% vs. 3.7%, p<0.001. Conversely, a larger proportion of ET->PD than ET patients reported rapid eye movement behavior disorder (51.9% vs. 10.0%, p<0.001, constipation (67.9% vs. 36.4%, p<0.001, and olfactory dysfunction (83.3% vs. 36.4%, p<0.001. Discussion: The subset of ET->PD patients may have distinct MFs and NMFs that should be assessed further for the possible predictive value for the emergence of PD.  

  11. Beta-blocker therapy for tremor in Parkinson's disease.

    Science.gov (United States)

    Crosby, N J; Deane, K H O; Clarke, C E

    2003-01-01

    The tremor of Parkinson's disease can cause considerable disability for the individual concerned. Traditional antiparkinsonian therapies such as levodopa have only a minor effect on tremor. Beta-blockers are used to attenuate other forms of tremor such as Essential Tremor or the tremor associated with anxiety. It is thought that beta-blockers may be of use in controlling the tremor of Parkinson's disease. To compare the efficacy and safety of adjuvant beta-blocker therapy against placebo for the treatment of tremor in patients with Parkinson's disease. Electronic searches of MEDLINE, EMBASE, SCISEARCH, BIOSIS, GEROLIT, OLDMEDLINE, LILACS, MedCarib, PASCAL, JICST-EPLUS, RUSSMED, DISSERTATION ABSTRACTS, SIGLE, ISI-ISTP, Aslib Index to Theses, The Cochrane Controlled Trials Register, Clinicaltrials.gov, metaRegister of Controlled Trials, NIDRR, NRR and CENTRAL were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of beta-blockers were contacted. Randomised controlled trials of adjuvant beta-blocker therapy versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease. Data was abstracted independently by two of the authors onto standardised forms and disagreements were resolved by discussion. Four randomised controlled trials were found comparing beta-blocker therapy with placebo in patients with idiopathic Parkinson's disease. These were double-blind cross-over studies involving a total of 72 patients. Three studies did not present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. The risk of a carry-over effect into the second arm meant that these results were not analysed. The fourth study presented data from each arm. This was in the form of a mean total score for tremor for each group. Details of the baseline scores, the numbers of patients in each group and standard deviations were not

  12. Hazard Monitoring of Growing Lava Flow Fields Using Seismic Tremor

    Science.gov (United States)

    Eibl, E. P. S.; Bean, C. J.; Jónsdottir, I.; Hoskuldsson, A.; Thordarson, T.; Coppola, D.; Witt, T.; Walter, T. R.

    2017-12-01

    An effusive eruption in 2014/15 created a 85 km2 large lava flow field in a remote location in the Icelandic highlands. The lava flows did not threaten any settlements or paved roads but they were nevertheless interdisciplinarily monitored in detail. Images from satellites and aircraft, ground based video monitoring, GPS and seismic recordings allowed the monitoring and reconstruction of a detailed time series of the growing lava flow field. While the use of satellite images and probabilistic modelling of lava flows are quite common tools to monitor the current and forecast the future growth direction, here we show that seismic recordings can be of use too. We installed a cluster of seismometers at 15 km from the vents and recorded the ground vibrations associated with the eruption. This seismic tremor was not only generated below the vents, but also at the edges of the growing lava flow field and indicated the parts of the lava flow field that were most actively growing. Whilst the time resolution is in the range of days for satellites, seismic stations easily sample continuously at 100 Hz and could therefore provide a much better resolution and estimate of the lava flow hazard in real-time.

  13. Annual modulation of non-volcanic tremor in northern Cascadia

    Science.gov (United States)

    Pollitz, Fred; Wech, Aaron G.; Kao, Honn; Burgmann, Roland

    2013-01-01

    Two catalogs of episodic tremor events in northern Cascadia, one from 2006 to 2012 and the other from 1997 to 2011, reveal two systematic patterns of tremor occurrence in southern Vancouver Island: (1) most individual events tend to occur in the third quarter of the year; (2) the number of events in prolonged episodes (i.e., episodic tremor and slip events), which generally propagate to Vancouver Island from elsewhere along the Cascadia subduction zone, is inversely correlated with the amount of precipitation that occurred in the preceding 2 months. We rationalize these patterns as the product of hydrologic loading of the crust of southern Vancouver Island and the surrounding continental region, superimposed with annual variations from oceanic tidal loading. Loading of the Vancouver Island crust in the winter (when the land surface receives ample precipitation) and unloading in the summer tends to inhibit and enhance downdip shear stress, respectively. Quantitatively, for an annually variable surface load, the predicted stress perturbation depends on mantle viscoelastic rheology. A mechanical model of downdip shear stress on the transition zone beneath Vancouver Island—driven predominantly by the annual hydrologic cycle—is consistent with the 1997–2012 tremor observations, with peak-to-peak downdip shear stress of about 0.4 kPa. This seasonal dependence of tremor occurrence appears to be restricted to southern Vancouver Island because of its unique situation as an elongated narrow-width land mass surrounded by ocean, which permits seasonal perturbations in shear stress at depth.

  14. [A Case of Psychogenic Tremor during Awake Craniotomy].

    Science.gov (United States)

    Kujirai, Kazumasa; Kamata, Kotoe; Uno, Toshihiro; Hamada, Keiko; Ozaki, Makoto

    2016-01-01

    A 31-year-old woman with a left frontal and parietal brain tumor underwent awake craniotomy. Propofol/remifentanil general anesthesia was induced. Following craniotomy, anesthetic administrations ceased. The level of consciousness was sufficient and she was not agitated. However, the patient complained of nausea 70 minutes into the awake phase. Considering the adverse effects of antiemetics and the upcoming surgical strategy, we did not give any medications. Nausea disappeared spontaneously while the operation was suspended. When surgical intervention extended to the left caudate nucleus, involuntary movement, classified as a tremor, with 5-6 Hz frequency, abruptly occurred on her left forearm. The patient showed emotional distress. Tremor appeared on her right forearm and subsequently spread to her lower extremities. Intravenous midazolam and fentanyl could not reduce her psychological stress. Since the tremor disturbed microscopic observation, general anesthesia was induced. Consequently, the tremor disappeared and did not recur. Based on the anatomical ground and the medication status, her involuntary movement was diagnosed as psychogenic tremor. Various factors can induce involuntary movements. In fact, intraoperative management of nausea and vomiting takes priority during awake craniotomy, but we should be reminded that some antiemetics potentially induce involuntary movement that could be caused by surgery around basal ganglia.

  15. Linking Essential Tremor to the Cerebellum: Clinical Evidence.

    Science.gov (United States)

    Benito-León, Julián; Labiano-Fontcuberta, Andrés

    2016-06-01

    Essential tremor (ET) might be a family of diseases unified by the presence of kinetic tremor, but also showing etiological, pathological, and clinical heterogeneity. In this review, we will describe the most significant clinical evidence, which suggests that ET is linked to the cerebellum. Data for this review were identified by searching PUBMED (January 1966 to May 2015) crossing the terms "essential tremor" (ET) and "cerebellum," which yielded 201 entries, 11 of which included the term "cerebellum" in the article title. This was supplemented by articles in the author's files that pertained to this topic. The wide spectrum of clinical features of ET that suggest that it originates as a cerebellar or cerebellar outflow problem include the presence of intentional tremor, gait and balance abnormalities, subtle features of dysarthria, and oculomotor abnormalities, as well as deficits in eye-hand coordination, motor learning deficits, incoordination during spiral drawing task, abnormalities in motor timing and visual reaction time, impairment of social abilities, improvement in tremor after cerebellar stroke, efficacy of deep brain stimulation (which blocks cerebellar outflow), and cognitive dysfunction. It is unlikely, however, that cerebellar dysfunction, per se, fully explains ET-associated dementia, because the cognitive deficits that have been described in patients with cerebellar lesions are generally mild. Overall, a variety of clinical findings suggest that in at least a sizable proportion of patients with ET, there is an underlying abnormality of the cerebellum and/or its pathways.

  16. SAFARI 2000 Atmospheric Aerosol Measurements, Hand-held Hazemeters, Zambia

    Data.gov (United States)

    National Aeronautics and Space Administration — In conjunction with the AERONET (AErosol RObotic NETwork) participation in SAFARI 2000, the USDA Forest Service deployed handheld hazemeters in western Zambia from...

  17. Handheld FRET-Aptamer Sensor for Water Safety, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Operational Technologies Corporation (OpTech) proposes to expand its current NASA Phase 2 SBIR handheld fluorometer and bone marker fluorescence resonance energy...

  18. The availability of relatively cheap hand-held Global Positioning ...

    African Journals Online (AJOL)

    spamer

    conditions, so the approach failed to produce results ... Hand-held Global Positioning System (GPS) receivers provide opportunities for detailed and rapid mapping of features ..... TICKELL, W. L. N. 1968 — The biology of the great albatrosses,.

  19. Imaging different components of a tectonic tremor sequence in southwestern Japan using an automatic statistical detection and location method

    Science.gov (United States)

    Poiata, Natalia; Vilotte, Jean-Pierre; Bernard, Pascal; Satriano, Claudio; Obara, Kazushige

    2018-06-01

    In this study, we demonstrate the capability of an automatic network-based detection and location method to extract and analyse different components of tectonic tremor activity by analysing a 9-day energetic tectonic tremor sequence occurring at the downdip extension of the subducting slab in southwestern Japan. The applied method exploits the coherency of multiscale, frequency-selective characteristics of non-stationary signals recorded across the seismic network. Use of different characteristic functions, in the signal processing step of the method, allows to extract and locate the sources of short-duration impulsive signal transients associated with low-frequency earthquakes and of longer-duration energy transients during the tectonic tremor sequence. Frequency-dependent characteristic functions, based on higher-order statistics' properties of the seismic signals, are used for the detection and location of low-frequency earthquakes. This allows extracting a more complete (˜6.5 times more events) and time-resolved catalogue of low-frequency earthquakes than the routine catalogue provided by the Japan Meteorological Agency. As such, this catalogue allows resolving the space-time evolution of the low-frequency earthquakes activity in great detail, unravelling spatial and temporal clustering, modulation in response to tide, and different scales of space-time migration patterns. In the second part of the study, the detection and source location of longer-duration signal energy transients within the tectonic tremor sequence is performed using characteristic functions built from smoothed frequency-dependent energy envelopes. This leads to a catalogue of longer-duration energy sources during the tectonic tremor sequence, characterized by their durations and 3-D spatial likelihood maps of the energy-release source regions. The summary 3-D likelihood map for the 9-day tectonic tremor sequence, built from this catalogue, exhibits an along-strike spatial segmentation of

  20. Imaging different components of a tectonic tremor sequence in southwestern Japan using an automatic statistical detection and location method

    Science.gov (United States)

    Poiata, Natalia; Vilotte, Jean-Pierre; Bernard, Pascal; Satriano, Claudio; Obara, Kazushige

    2018-02-01

    In this study, we demonstrate the capability of an automatic network-based detection and location method to extract and analyse different components of tectonic tremor activity by analysing a 9-day energetic tectonic tremor sequence occurring at the down-dip extension of the subducting slab in southwestern Japan. The applied method exploits the coherency of multi-scale, frequency-selective characteristics of non-stationary signals recorded across the seismic network. Use of different characteristic functions, in the signal processing step of the method, allows to extract and locate the sources of short-duration impulsive signal transients associated with low-frequency earthquakes and of longer-duration energy transients during the tectonic tremor sequence. Frequency-dependent characteristic functions, based on higher-order statistics' properties of the seismic signals, are used for the detection and location of low-frequency earthquakes. This allows extracting a more complete (˜6.5 times more events) and time-resolved catalogue of low-frequency earthquakes than the routine catalogue provided by the Japan Meteorological Agency. As such, this catalogue allows resolving the space-time evolution of the low-frequency earthquakes activity in great detail, unravelling spatial and temporal clustering, modulation in response to tide, and different scales of space-time migration patterns. In the second part of the study, the detection and source location of longer-duration signal energy transients within the tectonic tremor sequence is performed using characteristic functions built from smoothed frequency-dependent energy envelopes. This leads to a catalogue of longer-duration energy sources during the tectonic tremor sequence, characterized by their durations and 3-D spatial likelihood maps of the energy-release source regions. The summary 3-D likelihood map for the 9-day tectonic tremor sequence, built from this catalogue, exhibits an along-strike spatial segmentation of

  1. The approximate entropy of the electromyographic signals of tremor correlates with the osmotic fragility of human erythrocytes

    Directory of Open Access Journals (Sweden)

    Penha-Silva Nilson

    2010-06-01

    Full Text Available Abstract Background The main problem of tremor is the damage caused to the quality of the life of patients, especially those at more advanced ages. There is not a consensus yet about the origins of this disorder, but it can be examined in the correlations between the biological signs of aging and the tremor characteristics. Methods This work sought correlations between the osmotic fragility of erythrocytes and features extracted from electromyographic (EMG activity resulting from physiological tremor in healthy patients (N = 44 at different ages (24-87 years. The osmotic fragility was spectrophotometrically evaluated by the dependence of hemolysis, provided by the absorbance in 540 nm (A54o, on the concentration of NaCl. The data were adjusted to curves of sigmoidal regression and characterized by the half transition point (H50, amplitude of lysis transition (dx and values of A540 in the curve regions that characterize the presence of lysed (A1 and preserved erythrocytes (A2. The approximate entropy was estimated from EMG signals detected from the extensor carpi ulnaris muscle during the movement of the hand of subjects holding up a laser pen towards an Archimedes spiral, fixed in a whiteboard. The evaluations were carried out with the laser pen at rest, at the center of the spiral, and in movement from the center to the outside and from outside to the center. The correlations among the parameters of osmotic fragility, tremor and age were tested. Results Negative correlations with age were found for A1 and dx. With the hand at rest, a positive correlation with H50 was found for the approximate entropy. Negative correlations with H50 were found for the entropy with the hand in movement, as from the center to the outside or from the outside to the center of the spiral. Conclusion In healthy individuals, the increase in the erythrocyte osmotic fragility was associated with a decrease in the approximate entropy for rest tremor and with an increase

  2. Blood harmane, blood lead, and severity of hand tremor: evidence of additive effects.

    Science.gov (United States)

    Louis, Elan D; Factor-Litvak, Pam; Gerbin, Marina; Slavkovich, Vesna; Graziano, Joseph H; Jiang, Wendy; Zheng, Wei

    2011-03-01

    Tremor is a widespread phenomenon in human populations. Environmental factors are likely to play an etiological role. Harmane (1-methyl-9H-pyrido[3,4-β]indole) is a potent tremor-producing β-carboline alkaloid. Lead is another tremor-producing neurotoxicant. The effects of harmane and lead with respect to tremor have been studied in isolation. We tested the hypothesis that tremor would be particularly severe among individuals who had high blood concentrations of both of these toxicants. Blood concentrations of harmane and lead were each quantified in 257 individuals (106 essential tremor cases and 151 controls) enrolled in an environmental epidemiological study. Total tremor score (range = 0-36) was a clinical measure of tremor severity. The total tremor score ranged from 0 to 36, indicating that a full spectrum of tremor severities was captured in our sample. Blood harmane concentration correlated with total tremor score (p = 0.007), as did blood lead concentration (p = 0.045). The total tremor score was lowest in participants with both low blood harmane and lead concentrations (8.4 ± 8.2), intermediate in participants with high concentrations of either toxicant (10.5 ± 9.8), and highest in participants with high concentrations of both toxicants (13.7 ± 10.4) (p=0.01). Blood harmane and lead concentrations separately correlated with total tremor scores. Participants with high blood concentrations of both toxicants had the highest tremor scores, suggesting an additive effect of these toxicants on tremor severity. Given the very high population prevalence of tremor disorders, identifying environmental determinants is important for primary disease prevention. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Doctors' experience with handheld computers in clinical practice: qualitative study.

    Science.gov (United States)

    McAlearney, Ann Scheck; Schweikhart, Sharon B; Medow, Mitchell A

    2004-05-15

    To examine doctors' perspectives about their experiences with handheld computers in clinical practice. Qualitative study of eight focus groups consisting of doctors with diverse training and practice patterns. Six practice settings across the United States and two additional focus group sessions held at a national meeting of general internists. 54 doctors who did or did not use handheld computers. Doctors who used handheld computers in clinical practice seemed generally satisfied with them and reported diverse patterns of use. Users perceived that the devices helped them increase productivity and improve patient care. Barriers to use concerned the device itself and personal and perceptual constraints, with perceptual factors such as comfort with technology, preference for paper, and the impression that the devices are not easy to use somewhat difficult to overcome. Participants suggested that organisations can help promote handheld computers by providing advice on purchase, usage, training, and user support. Participants expressed concern about reliability and security of the device but were particularly concerned about dependency on the device and over-reliance as a substitute for clinical thinking. Doctors expect handheld computers to become more useful, and most seem interested in leveraging (getting the most value from) their use. Key opportunities with handheld computers included their use as a stepping stone to build doctors' comfort with other information technology and ehealth initiatives and providing point of care support that helps improve patient care.

  4. Introduction of handheld computing to a family practice residency program.

    Science.gov (United States)

    Rao, Goutham

    2002-01-01

    Handheld computers are valuable practice tools. It is important for residency programs to introduce their trainees and faculty to this technology. This article describes a formal strategy to introduce handheld computing to a family practice residency program. Objectives were selected for the handheld computer training program that reflected skills physicians would find useful in practice. TRGpro handheld computers preloaded with a suite of medical reference programs, a medical calculator, and a database program were supplied to participants. Training consisted of four 1-hour modules each with a written evaluation quiz. Participants completed a self-assessment questionnaire after the program to determine their ability to meet each objective. Sixty of the 62 participants successfully completed the training program. The mean composite score on quizzes was 36 of 40 (90%), with no significant differences by level of residency training. The mean self-ratings of participants across all objectives was 3.31 of 4.00. Third-year residents had higher mean self-ratings than others (mean of group, 3.62). Participants were very comfortable with practical skills, such as using drug reference software, and less comfortable with theory, such as knowing the different types of handheld computers available. Structured training is a successful strategy for introducing handheld computing to a residency program.

  5. 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.

  6. Essential Palatal Tremor Managed by Cognitive Behavioral Therapy

    Directory of Open Access Journals (Sweden)

    Tomohisa Kitamura

    2015-01-01

    Full Text Available Background. Essential palatal tremor is a disorder of unknown etiology involving involuntary movement of the uvula and soft palate. Treatment attempts including drugs or surgery have been conducted to cease the rhythmical movement. Case Report. A 55-year-old female visited our department complaining of a sudden, noticeable, intermittent, and rhythmical clicking noise in her throat for five years. Oral examination revealed rhythmical contractions of the soft palate with clicking at the frequency of 120 per min. Magnetic resonance imaging (MRI examination of the brain performed after consulting with the department of neuropathic internal medicine showed no abnormalities. Thus, essential palatal tremor was diagnosed. The symptoms improved with cognitive behavioral therapy without drugs or surgical treatments. The patient is now able to stop the rhythmical movement voluntarily. Discussion. Cognitive behavioral therapy might be suitable as first-line therapy for essential palatal tremor because the therapy is noninvasive.

  7. Subglacial discharge at tidewater glaciers revealed by seismic tremor

    Science.gov (United States)

    Bartholomaus, Timothy C.; Amundson, Jason M.; Walter, Jacob I.; O'Neel, Shad; West, Michael E.; Larsen, Christopher F.

    2015-01-01

    Subglacial discharge influences glacier basal motion and erodes and redeposits sediment. At tidewater glacier termini, discharge drives submarine terminus melting, affects fjord circulation, and is a central component of proglacial marine ecosystems. However, our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes. Here we report observations of hourly to seasonal variations in 1.5–10 Hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion, weather, or discrete icequakes. Our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer, in spite of fast basal motion that could limit the formation of subglacial conduits, and then abates during winter. Furthermore, tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally. Glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments.

  8. Treatment of essential and parkinsonian tremor with nipradilol.

    Science.gov (United States)

    Yoshii, F; Shinohara, Y; Takeoka, T; Kitagawa, Y; Akiyama, K; Yazaki, K

    1996-11-01

    Nipradilol is a new type of beta-blocker which possesses nitroglycerin-like vasodilating action in addition to beta-blocking action. We investigated the efficacy and safety of nipradilol for treating tremor in 20 patients with essential tremor (ET group) and 20 patients with Parkinson's disease (PD group). All patients received nipradilol (6 mg per day) for more than 8 weeks. Improvement of tremor appeared within 2 or 4 weeks after the start of nipradilol therapy, and the efficacy rate, defined as "moderately effective" or over, was 42.5% in all 40 patients, while that defined as "slightly effective" or over was 87.5%. The efficacy rate tended to be higher in the ET group compared with the PD group. Mean blood pressure was significantly decreased from the 4th week after the start of treatment and heart rate was significantly reduced from the 2nd week of treatment. Laboratory examination showed no significant changes.

  9. Atenolol vs. propranolol in essential tremor. A controlled, quantitative study.

    Science.gov (United States)

    Larsen, T A; Teräväinen, H; Calne, D B

    1982-11-01

    The beta-1 selective, hydrophilic adrenoceptor blocking drug atenolol (100 mg daily) was compared to the non-selective, lipid-soluble beta-blocker propranolol (240 mg daily), and to placebo, in a double-blind cross-over study in 24 patients with essential tremor. Atenolol and propranolol caused a similar decrease in heart rate. Both beta-blockers also suppressed the tremor intensity; there was no significant difference between them, but both were significantly better than placebo. These drugs did not affect tremor frequency. Twelve of the patients preferred propranolol subjectively, one preferred atenolol and none preferred placebo. No marked side-effects were observed. It was concluded that atenolol and other cardio-selective blockers offer an alternative for patients unable to tolerate the non-selective drugs. The site of action and receptor sub-type involved have still to be determined.

  10. 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

  11. MRI-guided focused ultrasound thalamotomy in non-ET tremor syndromes.

    Science.gov (United States)

    Fasano, Alfonso; Llinas, Maheleth; Munhoz, Renato P; Hlasny, Eugen; Kucharczyk, Walter; Lozano, Andres M

    2017-08-22

    To report the 6-month single-blinded results of unilateral thalamotomy with MRI-guided focused ultrasound (MRgFUS) in patients with tremors other than essential tremor. Three patients with tremor due to Parkinson disease, 2 with dystonic tremor in the context of cervicobrachial dystonia and writer's cramp, and 1 with dystonia gene-associated tremor underwent MRgFUS targeting the ventro-intermedius nucleus (Vim) of the dominant hemisphere. The primary endpoint was the reduction of lateralized items of the Tremor Rating Scale of contralateral hemibody assessed by a blinded rater. All patients achieved a statistically significant, immediate, and sustained improvement of the contralateral tremor score by 42.2%, 52.0%, 55.9%, and 52.9% at 1 week and 1, 3, and 6 months after the procedure, respectively. All patients experienced transient side effects and 2 patients experienced persistent side effects at the time of last evaluation: hemitongue numbness and hemiparesis with hemihypoesthesia. Vim MRgFUS is a promising, incision-free, but nevertheless invasive technique to effectively treat tremors other than essential tremor. Future studies on larger samples and longer follow-up will further define its effectiveness and safety. NCT02252380. This study provides Class IV evidence that for patients with tremor not caused by essential tremor, MRgFUS of the Vim improves the tremor of the contralateral hemibody at 6 months. © 2017 American Academy of Neurology.

  12. Laryngoscopy evaluation protocol for the differentiation of essential and dystonic voice tremor.

    Science.gov (United States)

    Moraes, Bruno Teixeira de; Biase, Noemi Grigoletto de

    2016-01-01

    Although syndromes that cause voice tremor have singular characteristics, the differential diagnosis of these diseases is a challenge because of the overlap of the existing signs and symptoms. To develop a task-specific protocol to assess voice tremor by means of nasofibrolaryngoscopy and to identify those tasks that can distinguish between essential and dystonic tremor syndromes. Cross-sectional study. The transnasal fiberoptic laryngoscopy protocol, which consisted of the assessment of palate, pharynx and larynx tremor during the performance of several vocal and non-vocal tasks with distinct phenomenological characteristics, was applied to 19 patients with voice tremor. Patients were diagnosed with essential or dystonic tremor according to the phenomenological characterization of each group. Once they were classified, the tasks associated with the presence of tremor in each syndrome were identified. The tasks that significantly contributed to the differential diagnosis between essential and dystonic tremor were /s/ production, continuous whistling and reduction of tremor in falsetto. These tasks were phenomenologically different with respect to the presence of tremor in the two syndromes. The protocol of specific tasks by means of transnasal fiberoptic laryngoscopy is a viable method to differentiate between essential and dystonic voice tremor syndromes through the following tasks: /s/ production, continuous whistling and reduction of tremor in falsetto. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  13. Introducing Handheld Computing for Interactive Medical Education

    Directory of Open Access Journals (Sweden)

    Joseph Finkelstein

    2005-04-01

    Full Text Available The goals of this project were: (1 development of an interactive multimedia medical education tool (CO-ED utilizing modern features of handheld computing (PDA and major constructs of adult learning theories, and (2 pilot testing of the computer-assisted education in residents and clinicians. Comparison of the knowledge scores using paired t-test demonstrated statistically significant increase in subject knowledge (p<0.01 after using CO-ED. Attitudinal surveys were analyzed by total score (TS calculation represented as a percentage of a maximal possible score. The mean TS was 74.5±7.1%. None of the subjects (N=10 had TS less than 65% and in half of the subjects (N=5 TS was higher than 75%. Analysis of the semi-structured in-depth interviews showed strong support of the study subjects in using PDA as an educational tool, and high acceptance of CO-ED user interface. We concluded that PDA have a significant potential as a tool for clinician education.

  14. An Adaptive Geometry Game for Handheld Devices

    Directory of Open Access Journals (Sweden)

    Harri Ketamo

    2003-01-01

    Full Text Available The development of adaptive learning systems is only in the very beginning. In fact, the concept of adaptive learning systems range from different user interfaces to behaviour adaptive systems as well as from the place and time independent systems to terminal independent systems. When approaching the concept of adaptive learning materials, we must first have conceptual models of the behaviour of different learners within digital environments.The aim of this study was to develop a geometry learning game that adapts to user’s behaviour. The learners in this study were six years old Finnish pre-school pupils. The adaptive system was very limited and the observed behaviour was defined as very simple. However, the software developed achieves good learning results among the tested pupils. The study shows that the learning effect is very promising with this kind of handheld platform and simple adaptation system. This study gives good visions of what can be achieved with more complex behaviour adaptive systems in the field of eLearning.

  15. Extensional rheometry with a handheld mobile device

    Science.gov (United States)

    Marshall, Kristin A.; Liedtke, Aleesha M.; Todt, Anika H.; Walker, Travis W.

    2017-06-01

    The on-site characterization of complex fluids is important for a number of academic and industrial applications. Consequently, a need exists to develop portable rheometers that can provide in the field diagnostics and serve as tools for rapid quality assurance. With the advancement of smartphone technology and the widespread global ownership of smart devices, mobile applications are attractive as platforms for rheological characterization. The present work investigates the use of a smartphone device for the extensional characterization of a series of Boger fluids composed of glycerol/water and poly(ethylene oxide), taking advantage of the increasing high-speed video capabilities (currently up to 240 Hz capture rate at 720p) of smartphone cameras. We report a noticeable difference in the characterization of samples with slight variations in polymer concentration and discuss current device limitations. Potential benefits of a handheld extensional rheometer include its use as a point-of-care diagnostic tool, especially in developing communities, as well as a simple and inexpensive tool for assessing product quality in industry.

  16. Hand-held optical fuel pin scanner

    International Nuclear Information System (INIS)

    Kirchner, T.L.; Powers, H.G.

    1987-01-01

    A portable, hand-held apparatus is described for optically scanning indicia imprinted about a planar end face of an article having an outer wall surface, the apparatus comprising: a supporting frame; light detector means fixed to the frame for digitizing light patterns directed thereto; indexing means on the frame for engaging the planar end face and locating the end face in a preselected focal plane on the frame. The indexing means has an inner wall surface complementary to the article wall surface for disposition thereabout and terminates in an end portion beyond the planar end face. The inner wall surface has a radially inwardly extending shoulder spaced from the end portion and engageable with the planar end face; light means directed onto the preselected focal plane; optical means mounted on the frame about a central axis, the optical means being optically interposed between the indexing means and the light detector means for directing reflected light from the preselected focal plane to the light detector means and including a dove prism centrally aligned along the central axis; and means for selectively rotating the dove prism relative to the frame about the central axis to thereby rotate the image from the focal plane as transmitted to the light detector means

  17. Robust sleep quality quantification method for a personal handheld device.

    Science.gov (United States)

    Shin, Hangsik; Choi, Byunghun; Kim, Doyoon; Cho, Jaegeol

    2014-06-01

    The purpose of this study was to develop and validate a novel method for sleep quality quantification using personal handheld devices. The proposed method used 3- or 6-axes signals, including acceleration and angular velocity, obtained from built-in sensors in a smartphone and applied a real-time wavelet denoising technique to minimize the nonstationary noise. Sleep or wake status was decided on each axis, and the totals were finally summed to calculate sleep efficiency (SE), regarded as sleep quality in general. The sleep experiment was carried out for performance evaluation of the proposed method, and 14 subjects participated. An experimental protocol was designed for comparative analysis. The activity during sleep was recorded not only by the proposed method but also by well-known commercial applications simultaneously; moreover, activity was recorded on different mattresses and locations to verify the reliability in practical use. Every calculated SE was compared with the SE of a clinically certified medical device, the Philips (Amsterdam, The Netherlands) Actiwatch. In these experiments, the proposed method proved its reliability in quantifying sleep quality. Compared with the Actiwatch, accuracy and average bias error of SE calculated by the proposed method were 96.50% and -1.91%, respectively. The proposed method was vastly superior to other comparative applications with at least 11.41% in average accuracy and at least 6.10% in average bias; average accuracy and average absolute bias error of comparative applications were 76.33% and 17.52%, respectively.

  18. Intermittent bilateral coherence in physiological and essential hand tremor

    Czech Academy of Sciences Publication Activity Database

    Chakraborty, Soma; Kopecká, J.; Šprdlík, Otakar; Hoskovcová, M.; Ulmanová, O.; Růžička, E.; Zápotocký, Martin

    2017-01-01

    Roč. 128, č. 4 (2017), s. 622-634 ISSN 1388-2457 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 ; RVO:67985556 Keywords : physiological tremor * essential tremor * bilateral coupling * coherence * ballistocardiac impulse * accelerometry * wavelet analysis Subject RIV: FH - Neurology; BC - Control Systems Theory (UTIA-B) OBOR OECD: Neurosciences (including psychophysiology; Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) (UTIA-B) Impact factor: 3.866, year: 2016

  19. Clinical neurogenetics: fragile x-associated tremor/ataxia syndrome.

    Science.gov (United States)

    Hall, Deborah A; O'Keefe, Joan A

    2013-11-01

    This article summarizes the clinical findings, genetics, pathophysiology, and treatment of fragile X-associated tremor ataxia syndrome. The disorder occurs from a CGG repeat (55-200) expansion in the fragile X mental retardation 1 gene. It manifests clinically in kinetic tremor, gait ataxia, and executive dysfunction, usually in older men who carry the genetic abnormality. The disorder has distinct radiographic and pathologic findings. Symptomatic treatment is beneficial in some patients. The inheritance is X-linked and family members may be at risk for other fragile X-associated disorders. This information is useful to neurologists, general practitioners, and geneticists. Copyright © 2013. Published by Elsevier Inc.

  20. Nadolol for lithium tremor in the presence of liver damage.

    Science.gov (United States)

    Dave, M; Langbart, M M

    1994-03-01

    Lithium-induced tremor classically responds to treatment with propranolol. Since it is metabolized in the liver, propranolol may not be the drug of choice in those patients who have compromised liver function or who are recovering from prior liver diseases. Another nonselective beta-adrenergic blocker, nadolol, has no hepatic biotransformation. We present here the first case report of successful treatment of lithium-induced tremor with nadolol, which was selected because the patient had compromised liver function. The patient's liver function tests remained stable with the therapy.

  1. Long-term Effect of Sodium Oxybate (Xyrem®) in Spasmodic Dysphonia with Vocal Tremor

    Science.gov (United States)

    Simonyan, Kristina; Frucht, Steven J.

    2013-01-01

    Background Symptoms of spasmodic dysphonia (SD) are usually managed successfully with botulinum toxin injections. Vocal tremor (VT), which accompanies SD, has a poor response to this treatment. Case Report We report a case of a female with SD and VT who became symptom-free for 10 months after the intake of a single dose of sodium oxybate (Xyrem®). The long-term treatment effect correlated with attenuated brain activity in the key regions of dystonic brain network. Discussion Our case demonstrates that the novel treatment of sodium oxybate may hold promise for SD patients, especially those who have associated VT. PMID:24386608

  2. Long-Term Effect of Sodium Oxybate (Xyrem® in Spasmodic Dysphonia with Vocal Tremor

    Directory of Open Access Journals (Sweden)

    Kristina Simonyan

    2013-12-01

    Full Text Available Background: Symptoms of spasmodic dysphonia (SD are usually managed successfully with botulinum toxin injections. Vocal tremor (VT, which accompanies SD, has a poor response to this treatment.Case Report: We report a case of a female with SD and VT who became symptom‐free for 10 months after the intake of a single dose of sodium oxybate (Xyrem®. The long‐term treatment effect correlated with attenuated brain activity in the key regions of dystonic brain network. Discussion: Our case demonstrates that the novel treatment of sodium oxybate may hold promise for SD patients, especially those who have associated VT.

  3. Evaluation of Handheld Scanners for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Wadea Ameen

    2018-01-01

    Full Text Available The process of generating a computerized geometric model for an existing part is known as Reverse Engineering (RE. It is a very useful technique in product development and plays a significant role in automotive, aerospace, and medical industries. In fact, it has been getting remarkable attention in manufacturing industries owing to its advanced data acquisition technologies. The process of RE is based on two primary steps: data acquisition (also known as scanning and data processing. To facilitate point data acquisition, a variety of scanning systems is available with different capabilities and limitations. Although the optical control of 3D scanners is fully developed, still several factors can affect the quality of the scanned data. As a result, the proper selection of scanning parameters, such as resolution, laser power, shutter time, etc., becomes very crucial. This kind of investigation can be very helpful and provide its users with guidelines to identify the appropriate factors. Moreover, it is worth noting that no single system is ideal in all applications. Accordingly, this work has compared two portable (handheld systems based on laser scanning and white light optical scanning for automotive applications. A car door containing a free-form surface has been used to achieve the above-mentioned goal. The design of experiments has been employed to determine the effects of different scanning parameters and optimize them. The capabilities and limitations have been identified by comparing the two scanners in terms of accuracy, scanning time, triangle numbers, ease of use, and portability. Then, the relationships between the system capabilities and the application requirements have been established. The results revealed that the laser scanner performed better than the white light scanner in terms of accuracy, while the white light scanner performed better in terms of acquisition speed and triangle numbers.

  4. A novel fully integrated handheld gamma camera

    International Nuclear Information System (INIS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2016-01-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  5. A novel fully integrated handheld gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Massari, R.; Ucci, A.; Campisi, C. [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy); Scopinaro, F. [University of Rome “La Sapienza”, S. Andrea Hospital, Rome (Italy); Soluri, A., E-mail: alessandro.soluri@ibb.cnr.it [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy)

    2016-10-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  6. Improved spatial targeting with directionally segmented deep brain stimulation leads for treating essential tremor

    Science.gov (United States)

    Keane, Maureen; Deyo, Steve; Abosch, Aviva; Bajwa, Jawad A.; Johnson, Matthew D.

    2012-08-01

    Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to exert a therapeutic effect on postural and kinetic tremor in patients with essential tremor (ET). For DBS leads implanted near the caudal border of Vim, however, there is an increased likelihood that one will also induce paresthesia side-effects by stimulating neurons within the sensory pathway of the ventral caudal (Vc) nucleus of thalamus. The aim of this computational study was to (1) investigate the neuronal pathways modulated by therapeutic, sub-therapeutic and paresthesia-inducing DBS settings in three patients with ET and (2) determine how much better an outcome could have been achieved had these patients been implanted with a DBS lead containing directionally segmented electrodes (dDBS). Multi-compartment neuron models of the thalamocortical, cerebellothalamic and medial lemniscal pathways were first simulated in the context of patient-specific anatomies, lead placements and programming parameters from three ET patients who had been implanted with Medtronic 3389 DBS leads. The models showed that in these patients, complete suppression of tremor was associated most closely with activating an average of 62% of the cerebellothalamic afferent input into Vim (n = 10), while persistent paresthesias were associated with activating 35% of the medial lemniscal tract input into Vc thalamus (n = 12). The dDBS lead design demonstrated superior targeting of the cerebello-thalamo-cortical pathway, especially in cases of misaligned DBS leads. Given the close proximity of Vim to Vc thalamus, the models suggest that dDBS will enable clinicians to more effectively sculpt current through and around thalamus in order to achieve a more consistent therapeutic effect without inducing side-effects.

  7. Nonlinear dynamic mechanism of vocal tremor from voice analysis and model simulations

    Science.gov (United States)

    Zhang, Yu; Jiang, Jack J.

    2008-09-01

    Nonlinear dynamic analysis and model simulations are used to study the nonlinear dynamic characteristics of vocal folds with vocal tremor, which can typically be characterized by low-frequency modulation and aperiodicity. Tremor voices from patients with disorders such as paresis, Parkinson's disease, hyperfunction, and adductor spasmodic dysphonia show low-dimensional characteristics, differing from random noise. Correlation dimension analysis statistically distinguishes tremor voices from normal voices. Furthermore, a nonlinear tremor model is proposed to study the vibrations of the vocal folds with vocal tremor. Fractal dimensions and positive Lyapunov exponents demonstrate the evidence of chaos in the tremor model, where amplitude and frequency play important roles in governing vocal fold dynamics. Nonlinear dynamic voice analysis and vocal fold modeling may provide a useful set of tools for understanding the dynamic mechanism of vocal tremor in patients with laryngeal diseases.

  8. 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.

    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

  9. 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

    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 cerebellar

  10. 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)

  11. Acoustic Characteristics of Simulated Respiratory-Induced Vocal Tremor

    Science.gov (United States)

    Lester, Rosemary A.; Story, Brad H.

    2013-01-01

    Purpose: The purpose of this study was to investigate the relation of respiratory forced oscillation to the acoustic characteristics of vocal tremor. Method: Acoustical analyses were performed to determine the characteristics of the intensity and fundamental frequency (F[subscript 0]) for speech samples obtained by Farinella, Hixon, Hoit, Story,…

  12. 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.

  13. Propranolol as an adjunct therapy for hyperthyroid tremor.

    Science.gov (United States)

    Henderson, J M; Portmann, L; Van Melle, G; Haller, E; Ghika, J A

    1997-01-01

    We evaluated the use of propranolol as an adjunct to carbimazole in the treatment of hyperthyroid tremor and tachycardia in a double-blind, cross-over and placebo-controlled study. Seven patients were given carbimazole plus either placebo or propranolol (40 mg) for 1 month and then switched to the alternative adjunct treatment for a further month. All patients showed significant improvements (p tremor amplitude after 1 or 2 months from baseline. One month after the baseline, the mean improvements of heart rate were 23% for the carbimazole + placebo group and 38% for carbimazole + propranolol group. Tremor also improved during the 1st month of the study by 31% in the carbimazole + placebo group versus 59% in the carbimazole + propranolol group. Whereas further improvements were observed in both variables in those receiving propranolol as the second adjunct treatment, this was not the case in those who received placebo during the same period. These findings confirm that the beta-blocker propranolol is a useful adjunct in the early treatment of both the tremor and tachycardia of hyperthyroidism.

  14. Listening carefully: unique observations of harmonic tremor at Lascar volcano, Chile

    Directory of Open Access Journals (Sweden)

    M. Hellweg

    1999-06-01

    Full Text Available During the deployment of Proyecto de Investigación Sismológica de la Cordillera Occidental 94 (PISCO'94 in the Atacama Desert of Northern Chile, a broadband seismic station and a network of three short-period three-component stations were installed around the active volcano Lascar. The resulting data set includes a sequence of harmonic tremor with a fundamental at about 0.63 Hz and up to 30 overtones lasting 18 h. Power spectra and spectrograms of Lascar's harmonic tremor from the various stations demonstrate that the frequencies recorded cannot be explained as path effects, and must therefore be attributed to mechanisms at or near the source. The polarization of the wavefield cannot simply be explained as the propagation of any of the classical types of seismic waves, thus we apply new methods to the data to investigate the narrowband signals of the harmonic peaks. While the amplitude characteristics of these signals cannot be correlated across the network, frequency characteristics of the harmonic wavefield are consistent across stations and components. The tremor's fundamental frequency changes at the same time at all stations, indicating that such changes must be caused at the source. In addition, a change in the frequency of the fundamental, f1, is reflected exactly in the frequencies of the overtones, nf1 and peak-broadening in the power spectrum is the result of shifts in the fundamental frequency. It is therefore unlikely that the overtones are produced as resonances. This spectral behavior indicates rather that the source is some resonance at a single frequency within the magma, magma/gas or gas parts of the volcano whose amplitude exceeds the range for which the assumptions of linear acoustics are valid.

  15. The BUMP model of response planning: intermittent predictive control accounts for 10 Hz physiological tremor.

    Science.gov (United States)

    Bye, Robin T; Neilson, Peter D

    2010-10-01

    Physiological tremor during movement is characterized by ∼10 Hz oscillation observed both in the electromyogram activity and in the velocity profile. We propose that this particular rhythm occurs as the direct consequence of a movement response planning system that acts as an intermittent predictive controller operating at discrete intervals of ∼100 ms. The BUMP model of response planning describes such a system. It forms the kernel of Adaptive Model Theory which defines, in computational terms, a basic unit of motor production or BUMP. Each BUMP consists of three processes: (1) analyzing sensory information, (2) planning a desired optimal response, and (3) execution of that response. These processes operate in parallel across successive sequential BUMPs. The response planning process requires a discrete-time interval in which to generate a minimum acceleration trajectory to connect the actual response with the predicted future state of the target and compensate for executional error. We have shown previously that a response planning time of 100 ms accounts for the intermittency observed experimentally in visual tracking studies and for the psychological refractory period observed in double stimulation reaction time studies. We have also shown that simulations of aimed movement, using this same planning interval, reproduce experimentally observed speed-accuracy tradeoffs and movement velocity profiles. Here we show, by means of a simulation study of constant velocity tracking movements, that employing a 100 ms planning interval closely reproduces the measurement discontinuities and power spectra of electromyograms, joint-angles, and angular velocities of physiological tremor reported experimentally. We conclude that intermittent predictive control through sequential operation of BUMPs is a fundamental mechanism of 10 Hz physiological tremor in movement. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. 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.

  17. Decisions at hand: a decision support system on handhelds.

    Science.gov (United States)

    Zupan, B; Porenta, A; Vidmar, G; Aoki, N; Bratko, I; Beck, J R

    2001-01-01

    One of the applications of clinical information systems is decision support. Although the advantages of utilizing such aids have never been theoretically disputed, they have been rarely used in practice. The factor that probably often limits the utility of clinical decision support systems is the need for computing power at the very site of decision making--at the place where the patient is interviewed, in discussion rooms, etc. The paper reports on a possible solution to this problem. A decision-support shell LogReg is presented, which runs on a handheld computer. A general schema for handheld-based decision support is also proposed, where decision models are developed on personal computers/workstations, encoded in XML and then transferred to handhelds, where the models are used within a decision support shell. A use case where LogReg has been applied to clinical outcome prediction in crush injury is presented.

  18. 75 FR 36678 - In the Matter of Certain Authentication Systems, Including Software and Handheld Electronic...

    Science.gov (United States)

    2010-06-28

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-697] In the Matter of Certain Authentication Systems, Including Software and Handheld Electronic Devices; Notice of Commission Decision Not to... importation of certain authentication systems, including software and handheld electronic devices, by reason...

  19. 75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

    Science.gov (United States)

    2010-02-24

    ... Communications System Server Software, Wireless Handheld Devices and Battery Packs; Notice of Investigation... within the United States after importation of certain wireless communications system server software... certain wireless communications system server software, wireless handheld devices or battery packs that...

  20. 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

  1. Sustained Medication Reduction Following Unilateral VIM Thalamic Stimulation for Essential Tremor.

    Science.gov (United States)

    Resnick, Andrew S; Okun, Michael S; Malapira, Teresita; Smith, Donald; Vale, Fernando L; Sullivan, Kelly; Miller, Amber; Jahan, Israt; Zesiewicz, Theresa

    2012-01-01

    Deep brain stimulation (DBS) is an increasingly utilized therapeutic modality for the management of medication refractory essential tremor (ET). The aim of this study was to determine whether DBS allowed for anti-tremor medication reduction within the year after the procedure was performed. We conducted a retrospective chart review and telephone interviews on 34 consecutive patients who had been diagnosed with ET, and who had undergone unilateral DBS surgery. Of the 34 patients in our cohort, 31 patients (91%) completely stopped all anti-tremor medications either before surgery (21 patients, 62%) or in the year following DBS surgery (10 patients, 29%). Patients who discontinued tremor medications before DBS surgery did so because their tremors either became refractory to anti-tremor medication, or they developed adverse events to tremor medications. Patients who stopped tremor medications after DBS surgery did so due to sufficient tremor control. Only three patients (9%) who were taking tremor medications at the time of surgery continued the use of a beta-blocker post-operatively for the purpose of hypertension management in all cases. The data from this study indicate that medication cessation is common following unilateral DBS for ET.

  2. Sustained Medication Reduction Following Unilateral VIM Thalamic Stimulation for Essential Tremor

    Directory of Open Access Journals (Sweden)

    Andrew S. Resnick

    2012-04-01

    Full Text Available Background: Deep brain stimulation (DBS is an increasingly utilized therapeutic modality for the management of medication refractory essential tremor (ET. The aim of this study was to determine whether DBS allowed for anti-tremor medication reduction within the year after the procedure was performed. Methods: We conducted a retrospective chart review and telephone interviews on 34 consecutive patients who had been diagnosed with ET, and who had undergone unilateral DBS surgery. Results: Of the 34 patients in our cohort, 31 patients (91% completely stopped all anti-tremor medications either before surgery (21 patients, 62% or in the year following DBS surgery (10 patients, 29%. Patients who discontinued tremor medications before DBS surgery did so because their tremors either became refractory to anti-tremor medication, or they developed adverse events to tremor medications. Patients who stopped tremor medications after DBS surgery did so due to sufficient tremor control. Only three patients (9% who were taking tremor medications at the time of surgery continued the use of a beta-blocker post-operatively for the purpose of hypertension management in all cases. Discussion: The data from this study indicate that medication cessation is common following unilateral DBS for ET. 

  3. 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

  4. Borehole Array Observations of Non-Volcanic Tremor at SAFOD

    Science.gov (United States)

    Ellsworth, W. L.; Luetgert, J. H.; Oppenheimer, D. H.

    2005-12-01

    We report on the observation of non-volcanic tremor made in the San Andreas Fault Observatory at Depth in May, 2005 during the deployment of a multi-level borehole seismic array in the SAFOD main hole. The seismic array consisted of 80 levels of hydraulically-clamped 3-component, 15 Hz omni-directional geophones spaced 15.24 m apart along a 1200 m section of the inclined borehole between 1538 and 2363 m below the ground surface. The array was provided by Paulsson Geophysical Services, Inc. (P/GSI), and recorded at a sample rate of 4000 sps on 24-bit Geode digital recorders provided by Geometrics, Inc. More than 2 TB of continuous data were recorded during the 2-week deployment. Selected local earthquakes and explosions recorded by the array are available at the Northern California Earthquake Data Center, and the entire unedited data set is available as assembled data at the IRIS Data Management Center. Both data sets are currently in the industry standard SEG2 format. Episodes of non-volcanic tremor are common along this reach of the San Andreas Fault according to Nadeau and Dolenc [2004, DOI: 10.1126/science.1107142], with many originating about 30 km southeast of SAFOD beneath the southern end of the Parkfield segment and northern end of the Simmler segment of the fault. We identified tremor episodes using spectrograms routinely produced by the Northern California Seismic Network (http://quake.usgs.gov/cgi-bin/sgrampark.pl) on which they appear as periods of elevated noise relative to the background. A particularly strong tremor episode occurred on May 10, 2005 between 19:39 and 20:00 UTC. In SAFOD, tremor spectral levels exceed the instrumental noise floor to at least 40 Hz. The spatially unaliased recording of the tremor wavefield on the P/GSI array reveal individual phases that can be tracked continuously across the array. The wavefield is composed of both up- and down-going shear waves that form quasi-stationary interference patterns in which areas of

  5. Gamma knife thalamotomy for Parkinson's tremor: A 5-year experience

    International Nuclear Information System (INIS)

    Duma, Christopher M.; Jacques, Deane B.; Kopyov, Oleg V.; Mark, Rufus J.; Copcutt, Brian G.

    1996-01-01

    Purpose: Elderly, high-risk surgical patients, may be unfit for radiofrequency thalamotomy for Parkinson's tremor. We have performed gamma knife radiosurgery in this select patient population, in lieu of open surgery, in an attempt at amelioration of disabling tremor. Materials and Methods: Radiosurgical nucleus ventralis intermedalis thalamotomy using gamma unit technique was performed on 38 patients (median age, 72 years; range: 50-88 years) over a period of 5 years. A median dose of 155 Gy (range: 110-160 Gy) was delivered using a single 4-mm collimator to 40 nuclei (2 patients underwent bilateral thalamotomy) using only anatomical atlas landmarks. The number of males and females were evenly divided, and their ages ranged from 50 to 88 years (median: 72 years). Two-thirds of the patients underwent left thalamotomy for right-sided trmor. Patients were followed-up for a median of 14 months (range: 6 to 43 months). Independent neurological evaluation of tremor as well as subjective patient evaluation were based on a 4-tiered scale: no improvement, mild improvement (0-33% effect), good improvement (33-66% effect), and excellent improvement (66-100%). Results: Eight thalamotomies (20%) failed, four (10%) gave mild improvement, and 28 (70%) gave good to excellent improvement of tremor (median time of onset of improvement was 3 months; range: 1-11 months). In 12 patients (32%) the tremor was eliminated completely. Concordance between independent neurologist evaluation and that of the patient was significant (p<0.001). Two patients in the failure group had an initial transient improvement. Two patients who underwent unilateral thalamotomy had bilateral improvement of their tremor. A permanent 5-6 mm lesion was seen on all follow-up MRIs and there were no radiological complications. A worsening of hand strength was seen in only patient. Conclusion: The safety and efficacy of gamma unit radiosurgical thalamotomy is on par with that of radiofrequency thalamotomy, and in a

  6. S-wave triggering of tremor beneath the Parkfield, California, section of the San Andreas fault by the 2011 Tohoku, Japan earthquake: observations and theory

    Science.gov (United States)

    Hill, David P.; Peng, Zhigang; Shelly, David R.; Aiken, Chastity

    2013-01-01

    The dynamic stresses that are associated with the energetic seismic waves generated by the Mw 9.0 Tohoku earthquake off the northeast coast of Japan triggered bursts of tectonic tremor beneath the Parkfield section of the San Andreas fault (SAF) at an epicentral distance of ∼8200  km. The onset of tremor begins midway through the ∼100‐s‐period S‐wave arrival, with a minor burst coinciding with the SHSH arrival, as recorded on the nearby broadband seismic station PKD. A more pronounced burst coincides with the Love arrival, followed by a series of impulsive tremor bursts apparently modulated by the 20‐ to 30‐s‐period Rayleigh wave. The triggered tremor was located at depths between 20 and 30 km beneath the surface trace of the fault, with the burst coincident with the S wave centered beneath the fault 30 km northwest of Parkfield. Most of the subsequent activity, including the tremor coincident with the SHSH arrival, was concentrated beneath a stretch of the fault extending from 10 to 40 km southeast of Parkfield. The seismic waves from the Tohoku epicenter form a horizontal incidence angle of ∼14°, with respect to the local strike of the SAF. Computed peak dynamic Coulomb stresses on the fault at tremor depths are in the 0.7–10 kPa range. The apparent modulation of tremor bursts by the small, strike‐parallel Rayleigh‐wave stresses (∼0.7  kPa) is likely enabled by pore pressure variations driven by the Rayleigh‐wave dilatational stress. These results are consistent with the strike‐parallel dynamic stresses (δτs) associated with the S, SHSH, and surface‐wave phases triggering small increments of dextral slip on the fault with a low friction (μ∼0.2). The vertical dynamic stresses δτd do not trigger tremor with vertical or oblique slip under this simple Coulomb failure model.

  7. Estimating seismic moment magnitude (Mw) of tremor bursts in northern Cascadia: Implications for the “seismic efficiency” of episodic tremor and slip

    Science.gov (United States)

    Kao, Honn; Wang, Kelin; Dragert, Herb; Kao, Jason Y.; Rogers, Garry

    2010-10-01

    We develop a method to estimate the seismic moments of deep non-volcanic tremor bursts observed in northern Cascadia. For each tremor burst, the maximum amplitudes at individual stations within a time window ±5 s around the predicted arrivals of the S phase are measured and compared to the maximum S amplitudes measured from synthetic seismograms. The proposed method is thoroughly calibrated using 464 local earthquakes and the results show excellent consistency between the reported ML and the estimated Mw. We apply the method to northern Cascadia tremors and infer that most bursts have Mw˜1.0-1.7. The corresponding b value appears to be 1, consistent with that of ordinary earthquakes but over a narrower Mw range. Comparison of cumulative tremor Mw and the Mw estimated from the accompanying slow slip suggests that the “seismic efficiency” of the Episodic Tremor and Slip (ETS) is of the order of 0.1% or less.

  8. Evolving Concepts in Posterior Subthalamic Area Deep Brain Stimulation for Treatment of Tremor: Surgical Neuroanatomy and Practical Considerations.

    Science.gov (United States)

    Ramirez-Zamora, Adolfo; Smith, Heather; Kumar, Vignessh; Prusik, Julia; Phookan, Sujoy; Pilitsis, Julie G

    2016-01-01

    Although thalamic deep brain stimulation (DBS) has been established as an effective therapy for refractory tremor in Parkinson's disease and essential tremor, reports investigating the efficacy of posterior subthalamic area (PSA) DBS for severe, debilitating tremors continue to emerge. However, questions regarding the optimal anatomical target, surgical approach, programming paradigms and effectiveness compared to other targets remain. In this report, we aimed to review the current literature to assess different stereotactic techniques, anatomical considerations, adverse effects and stimulation settings in PSA DBS. A comprehensive literature review was performed searching for articles discussing tremors and PSA stimulation. We performed a quantitative analysis comparing different DBS tremor targets. Tremor improvement is consistently documented in most reports with an average reduction in tremor of 79% depending on the specific tremor syndrome. Tremor benefit in patients with multiple sclerosis (MS) tremor was significantly higher than for other stimulation targets. Transient paresthesias, imbalance, dizziness and dysarthria are the most common side effects with PSA DBS. PSA DBS is an effective and safe treatment for tremor control and should be considered in patients with refractory tremors with associated cerebellar or dystonic features, proximal tremors and MS tremor. © 2016 S. Karger AG, Basel.

  9. Accuracy of Handheld Blood Glucose Meters at High Altitude

    NARCIS (Netherlands)

    de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.

    2010-01-01

    Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior

  10. Web-Based Spatial Training Using Handheld Touch Screen Devices

    Science.gov (United States)

    Martin-Dorta, Norena; Saorin, Jose Luis; Contero, Manuel

    2011-01-01

    This paper attempts to harness the opportunities for mobility and the new user interfaces that handheld touch screen devices offer, in a non-formal learning context, with a view to developing spatial ability. This research has addressed two objectives: first, analyzing the effects that training can have on spatial visualisation using the…

  11. Monitoring invasive plants using hand-held GIS technology

    Science.gov (United States)

    Theresa M. Mau-Crimmins; Barron J. Orr

    2005-01-01

    Successful control of invasive species requires a clear picture of the spatial extent of infestations. The latest mapping technology involves coupling global position systems and handheld computers running geographic information systems software in the field. A series of workshops applying this technology to mapping weeds was developed and presented to Weed Management...

  12. Technology-enabled division of labour: the use of handhelds

    NARCIS (Netherlands)

    Benders, J.G.J.M.; Schouteten, R.L.J.; Ruijsscher, C. de

    2012-01-01

    Using the task pool model and data from 15 establishments in the Dutch hospitality industry, this study shows how and why applying handhelds affects the division of labour. These devices allow to split the waiters' jobs into separate tasks which tend to be combined into two separate "sub jobs": the

  13. Technology-enabled division of labour : The use of handhelds

    NARCIS (Netherlands)

    Benders, J.G.J.M.; Schouteten, R.; de Ruijsscher, C.

    2012-01-01

    Using the task pool model and data from 15 establishments in the Dutch hospitality industry, this study shows how and why applying handhelds affects the division of labour. These devices allow to split the waiters' jobs into separate tasks which tend to be combined into two separate "sub jobs": the

  14. Diagnostic efficacy of handheld devices for emergency radiologic consultation.

    LENUS (Irish Health Repository)

    Toomey, Rachel J

    2010-02-01

    Orthopedic injury and intracranial hemorrhage are commonly encountered in emergency radiology, and accurate and timely diagnosis is important. The purpose of this study was to determine whether the diagnostic accuracy of handheld computing devices is comparable to that of monitors that might be used in emergency teleconsultation.

  15. Exploring streamwater mixing dynamics via handheld thermal infrared imagery

    NARCIS (Netherlands)

    Antonelli, Marta; Klaus, Julian; Smettem, Keith; Teuling, Ryan; Pfister, Laurent

    2017-01-01

    Stream confluences are important hotspots of aquatic ecological processes. Water mixing dynamics at stream confluences influence physio-chemical characteristics of the stream as well as sediment mobilisation and pollutant dispersal. In this study, we investigated the potential for handheld

  16. Neurosurgery contact handheld probe based on sapphire shaped crystal

    Science.gov (United States)

    Shikunova, I. A.; Stryukov, D. O.; Rossolenko, S. N.; Kiselev, A. M.; Kurlov, V. N.

    2017-01-01

    A handheld contact probe based on sapphire shaped crystal is developed for intraoperative spectrally-resolved optical diagnostics, laser coagulation and aspiration of malignant brain tissue. The technology was integrated into the neurosurgical workflow for intraoperative real-time identification and removing of invasive brain cancer.

  17. Octopus: embracing the energy efficiency of handheld multimedia computers

    NARCIS (Netherlands)

    Havinga, Paul J.M.; Smit, Gerardus Johannes Maria

    1999-01-01

    In the MOBY DICK project we develop and define the architecture of a new generation of mobile hand-held computers called Mobile Digital Companions. The Companions must meet several major requirements: high performance, energy efficient, a notion of Quality of Service (QoS), small size, and low

  18. Epilepsy Forewarning Using A Hand-Held Device

    Energy Technology Data Exchange (ETDEWEB)

    Hively, LM

    2005-02-21

    Over the last decade, ORNL has developed and patented a novel approach for forewarning of a large variety of machine and biomedical events. The present implementation uses desktop computers to analyze archival data. This report describes the next logical step in this effort, namely use of a hand-held device for the analysis.

  19. Imaging Emission Spectra with Handheld and Cellphone Cameras

    Science.gov (United States)

    Sitar, David

    2012-01-01

    As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

  20. Tremores intra e pós-operatório: prevenção e tratamento farmacológico Temblores intra y postoperatorio: prevención y tratamiento farmacológico Intra - and postoperative tremors: prevention and pharmacological treatment

    Directory of Open Access Journals (Sweden)

    Viviane Ferreira Albergaria

    2007-08-01

    ón de calor. E temblor postoperatorio es una desagradable complicación que está relacionada con el aumento de la morbidez. El temblor aumenta el metabolismo resultando en un aumento de 200% a 500% en el consumo de oxígeno. CONTENIDO: Discute las causas, prevención y tratamiento de los temblores intra y postoperatorio en pacientes adultos y pediátricos sometidos a la intervención quirúrgica bajo anestesia general o del neuroeje. CONCLUSIONES: Los temblores son, juntamente con náuseas y vómitos, causas de intensa incomodidad en la sala de recuperación pos anestésica, además de potencialmente perjudiciales por generar un aumento de la demanda metabólica. Aunque la presencia de temblores no haya sido directamente relacionada a la morbidez cardiaca, la prevención se ha hecho tema de debate y de varios artículos científicos. La prevención y el tratamiento de temblores deben ser implementados. Pacientes con reserva cardio pulmorar limitada pueden sufrir con la acidosis láctica, falta de saturación venosa mixta e hipoxemia.BACKGROUND AND OBJECTIVES: Tremors can be an adverse effect of the surgical intervention and anesthesia. The incidence of postoperative tremors varies from 6.3% to 66%. Young age, male gender, the use of halogenated anesthetics, and prolonged anesthesia or surgical procedure are related with tremors. Tremors are involuntary and present as oscillating muscular activity aiming at increasing heat production. Postoperative tremors are a disagreeable complication related with increased morbidity. Tremors increase the metabolism, resulting in a 200% to 500% increase in oxygen consumption. CONTENTS: The objective of this paper was to discuss the causes, prevention, and treatment of intra- and postoperative tremors in adults and children undergoing general anesthesia or neuroaxis anesthesia for surgical interventions. CONCLUSIONS: Tremors, along with nausea and vomiting, cause severe discomfort in the recovery room, besides being highly prejudicial

  1. Thalamic Ventral Intermediate Nucleus Deep Brain Stimulation for Orthostatic Tremor

    Directory of Open Access Journals (Sweden)

    Alexander C. Lehn

    2017-07-01

    Full Text Available Background: Orthostatic tremor (OT was first described in 1977. It is characterized by rapid tremor of 13–18 Hz and can be recorded in the lower limbs and trunk muscles. OT remains difficult to treat, although some success has been reported with deep brain stimulation (DBS.Case Report: We report a 68-year-old male with OT who did not improve significantly after bilateral thalamic stimulation.Discussion: Although some patients were described who improved after DBS surgery, more information is needed about the effect of these treatment modalities on OT, ideally in the form of randomized trial data. 

  2. 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. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. [Treatment of lithium tremor with the beta receptor blocker, pindolol].

    Science.gov (United States)

    Floru, L; Tegeler, J; Wolmsen, H

    1979-01-01

    In a cross-over study with Pindolol, 15 mg/day, against placebo, we studied during 4 weeks 22 patients aged between 20 and 65 years who where treated by means of lithium carbonate retard (Quilonum Retard). The tremor was measured twice a week by means of three apparative methods: an accelerometer, a 'hole-plate' and an 'aimed tapping plate', both constructed by Janke, and was also studied by means of a self-evaluation rating-scale. We obtained a positive therapeutic effect of Pindolol on lithium-induced tremor, which was statistically significant by means of the 'hole-plate' and of self-evaluation. Differences in results are discussed.

  4. Direction-Sensitive Hand-Held Gamma-Ray Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S.

    2012-10-04

    A novel, light-weight, hand-held gamma-ray detector with directional sensitivity is being designed. The detector uses a set of multiple rings around two cylindrical surfaces, which provides precise location of two interaction points on two concentric cylindrical planes, wherefrom the source location can be traced back by back projection and/or Compton imaging technique. The detectors are 2.0 × 2.0 mm europium-doped strontium iodide (SrI2:Eu2+) crystals, whose light output has been measured to exceed 120,000 photons/MeV, making it one of the brightest scintillators in existence. The crystal’s energy resolution, less than 3% at 662 keV, is also excellent, and the response is highly linear over a wide range of gamma-ray energies. The emission of SrI2:Eu2+ is well matched to both photo-multiplier tubes and blue-enhanced silicon photodiodes. The solid-state photomultipliers used in this design (each 2.0 × 2.0 mm) are arrays of active pixel sensors (avalanche photodiodes driven beyond their breakdown voltage in reverse bias); each pixel acts as a binary photon detector, and their summed output is an analog representation of the total photon energy, while the individual pixel accurately defines the point of interaction. A simple back-projection algorithm involving cone-surface mapping is being modeled. The back projection for an event cone is a conical surface defining the possible location of the source. The cone axis is the straight line passing through the first and second interaction points.

  5. Data for Users of Handheld Ion Mobility Spectrometers

    International Nuclear Information System (INIS)

    Keith A. Daum; Sandra L. Fox

    2008-01-01

    Chemical detection technology end-user surveys conducted by Idaho National Laboratory (INL) in 2005 and 2007 indicated that first responders believed manufacturers claims for instruments sometimes were not supported in field applications, and instruments sometimes did not meet their actual needs. Based on these findings, the Department of Homeland Security (DHS) asked INL to conduct a similar survey for handheld ion mobility spectrometers (IMS), which are used by a broad community of first responders as well as for other applications. To better access this broad community, the INL used the Center for Technology Commercialization, Inc. (CTC), Public Safety Technology Center (PSTC) to set up an online framework to gather information from users of handheld IMS units. This framework (Survey Monkey) was then used to perform an online Internet survey, augmented by e-mail prompts, to get information from first responders and personnel from various agencies about their direct experience with handheld IMS units. Overall, 478 individuals responded to the survey. Of these, 174 respondents actually owned a handheld IMS. Performance and satisfaction data from these 174 respondents are captured in this report. The survey identified the following observations: (1) The most common IMS unit used by respondents was the Advanced Portable Detector (APD 2000), followed by ChemRae, Sabre 4000, Sabre 2000, Draeger Multi IMS, Chemical Agent Monitor-2, Chemical Agent Monitor, Vapor Tracer, and Vapor Tracer 2. (2) The primary owners were HazMat teams (20%), fire services (14%), local police (12%), and sheriffs departments (9%). (3) IMS units are seldom used as part of an integrated system for detecting and identifying chemicals but instead are used independently. (4) Respondents are generally confused about the capabilities of their IMS unit. This is probably a result of lack of training. (5) Respondents who had no training or fewer than 8 hours were not satisfied with the overall operation

  6. Shooting performance is related to forearm temperature and hand tremor size.

    Science.gov (United States)

    Lakie, M; Villagra, F; Bowman, I; Wilby, R

    1995-08-01

    The changes in postural tremor of the hand and the subsequent effect on shooting performance produced by moderate cooling and heating of the forearm were studied in six subjects. Cooling produced a large decrease in tremor size of the ipsilateral hand, whereas warming the limb produced an increase in tremor size. Cooling or warming the forearm did not change the peak frequency of tremor significantly, which was quite stable for each subject. The improvement in shooting performance after cooling the forearm, as measured by grouping pattern of the shots, reached statistical significance and warming caused a significant worsening. This measure of performance was shown to correlate (r = 0.776) inversely with tremor size. The causes and implications of these changes are discussed. It is suggested that local cooling may be useful for people who wish temporarily to reduce tremor in order to improve dexterity for shooting and for other purposes.

  7. Propranolol, clonidine, urapidil and trazodone infusion in essential tremor: a double-blind crossover trial.

    Science.gov (United States)

    Caccia, M R; Osio, M; Galimberti, V; Cataldi, G; Mangoni, A

    1989-05-01

    Accelerometric tremorgrams were recorded from 25 subjects affected by essential tremor and analysed by a Berg-Fourier frequency analyser before and during venous infusion of the following drugs: propranolol (beta-blocker), clonidine (alpha-presynaptic adrenergic agonist), urapidil (alpha-postsynaptic blocker), trazodone (adrenolytic agent) and placebo. The washout interval between infusions was 3 days. Recordings and data analyses were performed in a double-blind crossover trial. Tremor was classified as: at rest; postural (arms hyperextended); and intention (finger-nose test). Analysis of the results showed that propranolol and clonidine reduced significantly (P = 0.01 and P = 0.009, respectively) the power spectrum of postural tremor, but left at rest and intention tremors unchanged. No significant effects on the tremor power spectrum were observed after placebo, urapidil or trazodone administration. None of the drugs had any effect on tremor frequency.

  8. Introduction to special section on phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor

    Science.gov (United States)

    Gomberg, Joan

    2010-01-01

    This paper introduces the special section on the "phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor" by highlighting key results of the studies published in it. Many of the results indicate that seismic and aseismic manifestations of slow slip reflect transient shear displacements on the plate interface, with the outstanding exception of northern Cascadia where tremor sources have been located on and above the plate interface (differing models of the plate interface there also need to be reconciled). Slow slip phenomena appear to result from propagating deformation that may develop with persistent gaps and segment boundaries. Results add to evidence that when tectonic deformation is relaxed via slow slip, most relaxation occurs aseismically but with seismic signals providing higher-resolution proxies for the aseismic slip. Instead of two distinct slip modes as suggested previously, lines between "fast" and "slow" slip more appropriately may be described as blurry zones. Results reported also show that slow slip sources do not coincide with a specific temperature or metamorphic reaction. Their associations with zones of high conductivity and low shear to compressional wave velocity ratios corroborate source models involving pore fluid pressure buildup and release. These models and spatial anticorrelations between earthquake and tremor activity also corroborate a linkage between slow slip and frictional properties transitional between steady state and stick-slip. Finally, this special section highlights the benefits of global and multidisciplinary studies, which demonstrate that slow phenomena are not confined to beneath the locked zone but exist in many settings.

  9. Altered brain network measures in patients with primary writing tremor

    Energy Technology Data Exchange (ETDEWEB)

    Lenka, Abhishek; Jhunjhunwala, Ketan Ramakant [National Institute of Mental Health and Neurosciences, Department of Clinical Neurosciences, Bangalore, Karnataka (India); National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neurology, 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); Yadav, Ravi; Pal, Pramod Kumar [National Institute of Mental Health and Neurosciences (NIMHANS), Department of Neurology, Bangalore, Karnataka (India)

    2017-10-15

    Primary writing tremor (PWT) is a rare task-specific tremor, which occurs only while writing or while adopting the hand in the writing position. The basic pathophysiology of PWT has not been fully understood. The objective of this study is to explore the alterations in the resting state functional brain connectivity, if any, in patients with PWT using graph theory-based analysis. This prospective case-control study included 10 patients with PWT and 10 age and gender matched healthy controls. All subjects underwent MRI in a 3-Tesla scanner. Several parameters of small-world functional connectivity were compared between patients and healthy controls by using graph theory-based analysis. There were no significant differences in age, handedness (all right handed), gender distribution (all were males), and MMSE scores between the patients and controls. The mean age at presentation of tremor in the patient group was 51.7 ± 8.6 years, and the mean duration of tremor was 3.5 ± 1.9 years. Graph theory-based analysis revealed that patients with PWT had significantly lower clustering coefficient and higher path length compared to healthy controls suggesting alterations in small-world architecture of the brain. The clustering coefficients were lower in PWT patients in left and right medial cerebellum, right dorsolateral prefrontal cortex (DLPFC), and left posterior parietal cortex (PPC). Patients with PWT have significantly altered small-world brain connectivity in bilateral medial cerebellum, right DLPFC, and left PPC. Further studies with larger sample size are required to confirm our results. (orig.)

  10. Altered brain network measures in patients with primary writing tremor

    International Nuclear Information System (INIS)

    Lenka, Abhishek; Jhunjhunwala, Ketan Ramakant; Panda, Rajanikant; Saini, Jitender; Bharath, Rose Dawn; Yadav, Ravi; Pal, Pramod Kumar

    2017-01-01

    Primary writing tremor (PWT) is a rare task-specific tremor, which occurs only while writing or while adopting the hand in the writing position. The basic pathophysiology of PWT has not been fully understood. The objective of this study is to explore the alterations in the resting state functional brain connectivity, if any, in patients with PWT using graph theory-based analysis. This prospective case-control study included 10 patients with PWT and 10 age and gender matched healthy controls. All subjects underwent MRI in a 3-Tesla scanner. Several parameters of small-world functional connectivity were compared between patients and healthy controls by using graph theory-based analysis. There were no significant differences in age, handedness (all right handed), gender distribution (all were males), and MMSE scores between the patients and controls. The mean age at presentation of tremor in the patient group was 51.7 ± 8.6 years, and the mean duration of tremor was 3.5 ± 1.9 years. Graph theory-based analysis revealed that patients with PWT had significantly lower clustering coefficient and higher path length compared to healthy controls suggesting alterations in small-world architecture of the brain. The clustering coefficients were lower in PWT patients in left and right medial cerebellum, right dorsolateral prefrontal cortex (DLPFC), and left posterior parietal cortex (PPC). Patients with PWT have significantly altered small-world brain connectivity in bilateral medial cerebellum, right DLPFC, and left PPC. Further studies with larger sample size are required to confirm our results. (orig.)

  11. Altered brain network measures in patients with primary writing tremor.

    Science.gov (United States)

    Lenka, Abhishek; Jhunjhunwala, Ketan Ramakant; Panda, Rajanikant; Saini, Jitender; Bharath, Rose Dawn; Yadav, Ravi; Pal, Pramod Kumar

    2017-10-01

    Primary writing tremor (PWT) is a rare task-specific tremor, which occurs only while writing or while adopting the hand in the writing position. The basic pathophysiology of PWT has not been fully understood. The objective of this study is to explore the alterations in the resting state functional brain connectivity, if any, in patients with PWT using graph theory-based analysis. This prospective case-control study included 10 patients with PWT and 10 age and gender matched healthy controls. All subjects underwent MRI in a 3-Tesla scanner. Several parameters of small-world functional connectivity were compared between patients and healthy controls by using graph theory-based analysis. There were no significant differences in age, handedness (all right handed), gender distribution (all were males), and MMSE scores between the patients and controls. The mean age at presentation of tremor in the patient group was 51.7 ± 8.6 years, and the mean duration of tremor was 3.5 ± 1.9 years. Graph theory-based analysis revealed that patients with PWT had significantly lower clustering coefficient and higher path length compared to healthy controls suggesting alterations in small-world architecture of the brain. The clustering coefficients were lower in PWT patients in left and right medial cerebellum, right dorsolateral prefrontal cortex (DLPFC), and left posterior parietal cortex (PPC). Patients with PWT have significantly altered small-world brain connectivity in bilateral medial cerebellum, right DLPFC, and left PPC. Further studies with larger sample size are required to confirm our results.

  12. Is there a Premotor Phase of Essential Tremor?

    Directory of Open Access Journals (Sweden)

    Abhishek Lenka

    2017-10-01

    Full Text Available Background: Essential tremor (ET is the most common tremor disorder. In addition to its hallmark feature, kinetic tremor of the upper limbs, patients may have a number of non-motor symptoms and signs (NMS. Several lines of evidence suggest that ET is a neurodegenerative disorder and certain NMS may antedate the onset of tremor. This article comprehensively reviews the evidence for the existence of a "premotor phase" of ET, and discusses plausible biological explanations and implications.Methods: A PubMed search in May 2017 identified articles for this review.Results: The existence of a premotor phase of ET gains support primarily from longitudinal data. In individuals who develop incident ET, baseline (i.e., premotor evaluations reveal greater cognitive dysfunction, a faster rate of cognitive decline, and the presence of a protective effect of education against dementia. In addition, baseline evaluations also reveal more self-reported depression, antidepressant medication use, and shorter sleep duration in individuals who eventually develop incident ET. In cross-sectional studies, certain personality traits and NMS (e.g., olfactory dysfunction also suggest the existence of a premotor phase.Discussion: There is preliminary evidence supporting the existence of a premotor phase of ET. The mechanisms are unclear; however, the presence of Lewy bodies in some ET brains in autopsy studies and involvement of multiple neural networks in ET as evident from the neuroimaging studies, are possible contributors. Most evidence is from a longitudinal cohort (Neurological Disorders of Central Spain: NEDICES; additional longitudinal studies are warranted to gain better insights into the premotor phase of ET.

  13. Fentanyl bolus induces muscle tremors in sevoflurane-anaesthetized piglets.

    Science.gov (United States)

    Ringer, S K; Spielmann, N; Weiss, M; Mauch, J Y

    2016-08-01

    Intravenous fentanyl (10 mcg/kg) or saline (control) was randomly administered to 10 healthy sevoflurane-mono-anaesthetized piglets. Trembling was assessed by two blinded observers using a visual analogue scale (VAS) and a simple ordinal scale at baseline and 5 min (T5) after drug administration. If no trembling was observed at that time point, the opposite treatment was administered and piglets were re-evaluated after another 5 min (T10). Four out of five piglets showed trembling after fentanyl (T5), while none given saline showed any trembling. With fentanyl the VAS scores were significantly higher at T5 compared either with baseline or with the control treatment. Control animals received fentanyl after the 5 min evaluation and all piglets showed clear trembling afterwards. The median time after fentanyl administration until first muscle tremors was 51 (20-840) s. In summary, nine out of 10 sevoflurane-anaesthetized piglets showed muscle tremors after intravenous fentanyl. Tremors subsided over time and no specific treatment was necessary. © The Author(s) 2015.

  14. Orthostatic Tremor: An Update on a Rare Entity

    Science.gov (United States)

    Benito-León, Julián; Domingo-Santos, Ángela

    2016-01-01

    Background Orthostatic tremor (OT) remains among the most intriguing and poorly understood of movement disorders. Compared to Parkinson’s disease or even essential tremor, there are very few articles addressing more basic science issues. In this review, we will discuss the findings of main case series on OT, including data on etiology, pathophysiology, diagnostic approach, treatment strategies, and outcome. Methods Data for this review were identified by searching PUBMED (January 1966 to August 2016) for the terms “orthostatic tremor” or “shaky leg syndrome,” which yielded 219 entries. We did not exclude papers on the basis of language, country, or publication date. The electronic database searches were supplemented by articles in the authors’ files that pertained to this topic. Results Owing to its rarity, the current understanding of OT is limited and is mostly based on small case series or case reports. Despite this, a growing body of evidence indicates that OT might be a progressive condition that is clinically heterogeneous (primary vs. secondary cases) with a broader spectrum of clinical features, mainly cerebellar signs, and possible cognitive impairment and personality disturbances. Along with this, advanced neuroimaging techniques are now demonstrating distinct anatomical and functional changes, some of which are consistent with neuronal loss. Discussion OT might be a family of diseases, unified by the presence of leg tremor, but further characterized by etiological and clinical heterogeneity. More work is needed to understand the pathogenesis of this condition. PMID:27713855

  15. TREMOR: A wireless MEMS accelerograph for dense arrays

    Science.gov (United States)

    Evans, J.R.; Hamstra, R.H.; Kundig, C.; Camina, P.; Rogers, J.A.

    2005-01-01

    The ability of a strong-motion network to resolve wavefields can be described on three axes: frequency, amplitude, and space. While the need for spatial resolution is apparent, for practical reasons that axis is often neglected. TREMOR is a MEMS-based accelerograph using wireless Internet to minimize lifecycle cost. TREMOR instruments can economically augment traditional ones, residing between them to improve spatial resolution. The TREMOR instrument described here has dynamic range of 96 dB between ??2 g, or 102 dB between ??4 g. It is linear to ???1% of full scale (FS), with a response function effectively shaped electronically. We developed an economical, very low noise, accurate (???1%FS) temperature compensation method. Displacement is easily recovered to 10-cm accuracy at full bandwidth, and better with care. We deployed prototype instruments in Oakland, California, beginning in 1998, with 13 now at mean spacing of ???3 km - one of the most densely instrumented urban centers in the United States. This array is among the quickest in returning (PGA, PGV, Sa) vectors to ShakeMap, ???75 to 100 s. Some 13 events have been recorded. A ShakeMap and an example of spatial variability are shown. Extensive tests of the prototypes for a commercial instrument are described here and in a companion paper. ?? 2005, Earthquake Engineering Research Institute.

  16. Orthostatic Tremor: A Spectrum of Fast and Slow Frequencies or Distinct Entities?

    OpenAIRE

    Rigby, Heather B.; Rigby, Matthew H.; Caviness, John N.

    2015-01-01

    Background: Orthostatic tremor (OT) is defined by the presence of a high-frequency (13–18 Hz) tremor of the legs upon standing associated with a feeling of unsteadiness. However, some patients have discharge frequencies of <13 Hz, so-called “slow OT”. The aim of this study was to characterize patients with unsteadiness upon standing found to have <13 Hz tremor discharges on neurophysiologic testing. Methods: A retrospective review was performed on all subjects with a d...

  17. Using an Earthquake Simulator to Model Tremor Along a Strike Slip Fault

    Science.gov (United States)

    Cochran, E. S.; Richards-Dinger, K. B.; Kroll, K.; Harrington, R. M.; Dieterich, J. H.

    2013-12-01

    We employ the earthquake simulator, RSQSim, to investigate the conditions under which tremor occurs in the transition zone of the San Andreas fault. RSQSim is a computationally efficient method that uses rate- and state- dependent friction to simulate a wide range of event sizes for long time histories of slip [Dieterich and Richards-Dinger, 2010; Richards-Dinger and Dieterich, 2012]. RSQSim has been previously used to investigate slow slip events in Cascadia [Colella et al., 2011; 2012]. Earthquakes, tremor, slow slip, and creep occurrence are primarily controlled by the rate and state constants a and b and slip speed. We will report the preliminary results of using RSQSim to vary fault frictional properties in order to better understand rupture dynamics in the transition zone using observed characteristics of tremor along the San Andreas fault. Recent studies of tremor along the San Andreas fault provide information on tremor characteristics including precise locations, peak amplitudes, duration of tremor episodes, and tremor migration. We use these observations to constrain numerical simulations that examine the slip conditions in the transition zone of the San Andreas Fault. Here, we use the earthquake simulator, RSQSim, to conduct multi-event simulations of tremor for a strike slip fault modeled on Cholame section of the San Andreas fault. Tremor was first observed on the San Andreas fault near Cholame, California near the southern edge of the 2004 Parkfield rupture [Nadeau and Dolenc, 2005]. Since then, tremor has been observed across a 150 km section of the San Andreas with depths between 16-28 km and peak amplitudes that vary by a factor of 7 [Shelly and Hardebeck, 2010]. Tremor episodes, comprised of multiple low frequency earthquakes (LFEs), tend to be relatively short, lasting tens of seconds to as long as 1-2 hours [Horstmann et al., in review, 2013]; tremor occurs regularly with some tremor observed almost daily [Shelly and Hardebeck, 2010; Horstmann

  18. Aging, hypertension and physiological tremor: the contribution of the cardioballistic impulse to tremorgenesis in older adults.

    Science.gov (United States)

    Morrison, Steven; Sosnoff, Jacob J; Heffernan, Kevin S; Jae, Sae Young; Fernhall, Bo

    2013-03-15

    For older adults, an increase in physiological tremor is a common motor feature. This increase is believed to primarily reflect a general decline in function of the neuromuscular system. However, given that tremor is derived from a number of intrinsic sources, age-related changes in other physiological functions like the cardiac system may also negatively alter tremor output. The aim of this study was to examine what impact age and increased cardiac input (hypertension) have on physiological tremor. Heart rate, blood pressure, and postural/resting tremor were recorded in three groups; 1) young, healthy adults, 2) old, normotensive adults, and 3) old, hypertensive adults. The results demonstrated that the old hypertensive adults had greater postural tremor compared to the young healthy individuals. Coherence analysis revealed significant coupling between blood pressure-tremor and between heart rate-tremor for all individuals. The strength of this coupling was greatest for the older, hypertensive individuals. Together these results show that, for older adults, the combined effects of age and cardiac disease have the greatest impact on physiological tremor rather than any single factor alone. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Deep Brain Stimulation for the Treatment of Tremor and Ataxia Associated with Abetalipoproteinemia

    Directory of Open Access Journals (Sweden)

    Antonios Mammis

    2012-07-01

    Full Text Available Background: Abetalipoproteinemia is a rare disorder of fat absorption, characterized by vitamin deficiency, acanthocytosis, and neurologic symptoms including ataxia and tremor.Case Report: A 41-year-old male with abetalipoproteinemia is presented. He underwent staged bilateral thalamic deep brain stimulation (DBS for the treatment of his tremors. After DBS, the patient achieved significant improvements in his tremors, ataxia, and quality of life.Discussion: Thalamic DBS proved to be both safe and efficacious in the management of ataxia and tremors in a patient with abetalipoproteinemia. This is the first report of DBS in abetalipoproteinemia in the literature. 

  20. White matter microstructure damage in tremor-dominant Parkinson's disease patients

    International Nuclear Information System (INIS)

    Luo, ChunYan; Song, Wei; Chen, Qin; Yang, Jing; Shang, Hui-Fang; Gong, QiYong

    2017-01-01

    Resting tremor is one of the cardinal motor features of Parkinson's disease (PD). Several lines of evidence suggest resting tremor may have different underlying pathophysiological processes from those of bradykinesia and rigidity. The current study aims to identify white matter microstructural abnormalities associated with resting tremor in PD. We recruited 60 patients with PD (30 with tremor-dominant PD and 30 with nontremor-dominant PD) and 26 normal controls. All participants underwent clinical assessment and diffusion tensor MRI. We used tract-based spatial statistics to investigate white matter integrity across the entire white matter tract skeleton. Compared with both healthy controls and the nontremor-dominant PD patients, the tremor-dominant PD patients were characterized by increased mean diffusivity (MD) and axial diffusivity (AD) along multiple white matter tracts, mainly involving the cerebello-thalamo-cortical (CTC) pathway. The mean AD value in clusters with significant difference was correlated with resting tremor score in the tremor-dominant PD patients. There was no significant difference between the nontremor-dominant PD patients and controls. Our results support the notion that resting tremor in PD is a distinct condition in which significant microstructural white matter changes exist and provide evidence for the involvement of the CTC in tremor genesis of PD. (orig.)

  1. White matter microstructure damage in tremor-dominant Parkinson's disease patients

    Energy Technology Data Exchange (ETDEWEB)

    Luo, ChunYan; Song, Wei; Chen, Qin; Yang, Jing; Shang, Hui-Fang [Sichuan University, Department of Neurology, West China Hospital, Chengdu, Sichuan (China); Gong, QiYong [Sichuan University, Huaxi MR Research Center, Department of Radiology, West China Hospital, Chengdu, Sichuan (China)

    2017-07-15

    Resting tremor is one of the cardinal motor features of Parkinson's disease (PD). Several lines of evidence suggest resting tremor may have different underlying pathophysiological processes from those of bradykinesia and rigidity. The current study aims to identify white matter microstructural abnormalities associated with resting tremor in PD. We recruited 60 patients with PD (30 with tremor-dominant PD and 30 with nontremor-dominant PD) and 26 normal controls. All participants underwent clinical assessment and diffusion tensor MRI. We used tract-based spatial statistics to investigate white matter integrity across the entire white matter tract skeleton. Compared with both healthy controls and the nontremor-dominant PD patients, the tremor-dominant PD patients were characterized by increased mean diffusivity (MD) and axial diffusivity (AD) along multiple white matter tracts, mainly involving the cerebello-thalamo-cortical (CTC) pathway. The mean AD value in clusters with significant difference was correlated with resting tremor score in the tremor-dominant PD patients. There was no significant difference between the nontremor-dominant PD patients and controls. Our results support the notion that resting tremor in PD is a distinct condition in which significant microstructural white matter changes exist and provide evidence for the involvement of the CTC in tremor genesis of PD. (orig.)

  2. Co-Prevalence of Tremor with Spasmodic Dysphonia: A Case-Control Study

    Science.gov (United States)

    White, Laura; Klein, Adam; Hapner, Edie; Delgaudio, John; Hanfelt, John; Jinnah, H. A.; Johns, Michael

    2011-01-01

    OBJECTIVES/HYPOTHESIS The aim of this study was to define the co-prevalence of tremor with spasmodic dysphonia (SD). STUDY DESIGN A single institution prospective, case-control study was performed from May 2010 to July 2010. METHODS Consecutive patients with SD (cases) and other voice disorders (controls) were enrolled prospectively. Each participant underwent a voice evaluation and an evaluation for tremor. RESULTS 146 voice disorder controls and 128 patients with SD were enrolled. 26% of patients with SD had vocal tremor, 21% had non-vocal tremor. Patients with SD were 2.8 times more likely to have co-prevalent tremor than the control group (OR = 2.81; 95% CI, 1.55 to 5.08) and only 35% of patients with SD had been seen by a neurologist for the evaluation of dystonia and tremor. CONCLUSIONS Tremor is highly prevalent in patients with SD. It is important for each patient diagnosed with SD to undergo an evaluation for tremor, this is especially important in patients diagnosed with vocal tremor. Level of evidence 3b. PMID:21792965

  3. Classification and Visualization of Physical and Chemical Properties of Falsified Medicines with Handheld Raman Spectroscopy and X-Ray Computed Tomography.

    Science.gov (United States)

    Kakio, Tomoko; Yoshida, Naoko; Macha, Susan; Moriguchi, Kazunobu; Hiroshima, Takashi; Ikeda, Yukihiro; Tsuboi, Hirohito; Kimura, Kazuko

    2017-09-01

    Analytical methods for the detection of substandard and falsified medical products (SFs) are important for public health and patient safety. Research to understand how the physical and chemical properties of SFs can be most effectively applied to distinguish the SFs from authentic products has not yet been investigated enough. Here, we investigated the usefulness of two analytical methods, handheld Raman spectroscopy (handheld Raman) and X-ray computed tomography (X-ray CT), for detecting SFs among oral solid antihypertensive pharmaceutical products containing candesartan cilexetil as an active pharmaceutical ingredient (API). X-ray CT visualized at least two different types of falsified tablets, one containing many cracks and voids and the other containing aggregates with high electron density, such as from the presence of the heavy elements. Generic products that purported to contain equivalent amounts of API to the authentic products were discriminated from the authentic products by the handheld Raman and the different physical structure on X-ray CT. Approach to investigate both the chemical and physical properties with handheld Raman and X-ray CT, respectively, promise the accurate discrimination of the SFs, even if their visual appearance is similar with authentic products. We present a decision tree for investigating the authenticity of samples purporting to be authentic commercial tablets. Our results indicate that the combination approach of visual observation, handheld Raman and X-ray CT is a powerful strategy for nondestructive discrimination of suspect samples.

  4. 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

  5. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Delayed dynamic triggering of deep tremor along the Parkfield-Cholame section of the San Andreas Fault following the 2014 M6.0 South Napa earthquake

    Science.gov (United States)

    Peng, Zhigang; Shelly, David R.; Ellsworth, William L.

    2015-01-01

    Large, distant earthquakes are known to trigger deep tectonic tremor along the San Andreas Fault and in subduction zones. However, there are relatively few observations of triggering from regional distance earthquakes. Here we show that a small tremor episode about 12–18 km NW of Parkfield was triggered during and immediately following the passage of surface waves from the 2014 Mw 6.0 South Napa main shock. More notably, a major tremor episode followed, beginning about 12 h later, and centered SE of Parkfield near Cholame. This major episode is one of the largest seen over the past several years, containing intense activity for ~3 days and taking more than 3 weeks to return to background levels. This episode showed systematic along-strike migration at ~5 km/d, suggesting that it was driven by a slow-slip event. Our results suggest that moderate-size earthquakes are capable of triggering major tremor and deep slow slip at regional distances.

  7. Nonvolcanic tremors and their correlation with slow slip events in Mexico

    Science.gov (United States)

    Kolstoglodov, V.; Shapiro, N. M.; Larson, K.; Payero, J.; Husker, A.; Santiago, L. A.; Clayton, R.; Peyrat, S.

    2009-04-01

    Significant activity of nonvolcanic tremor (NVT) has been observed in the central Mexico (Guerrero) subduction zone since 2001 when continuous seismic records became available. Albeit the quality of these records is poor, it is possible to estimate a temporal variation of energy in the range of 1-2Hz (best signal/noise ratio for the NVT), which clearly indicate the maximum of NVT energy release (En) during the 2001-2002 and 2006 large aseismic slow slip events (SSE) registered by a GPS network. In particular the En is higher for the 2001-2002 SSE which had larger surface displacements and extension than the 2006 SSE. A more detailed and accurate study of NVT activity was carried out using the data collected during the MASE experiment in Mexico. MASE consisted of 100 broad band seismometers in operation for ~2.5 years (2005-2007) along the profile oriented SSW-NNE from Acapulco, and crossing over the subduction zone for a distance of ~500 km. Epicenters and depths of individual tremor events determined using the envelope cross-correlation technique have rather large uncertainties partly originated from the essentially 2D geometry of the network. The "energy" approach is more efficient in this case because it provides an average NVT activity evolution in time and space. The data processing consists of a band pass (1-2Hz) filter of the raw 100 Hz sampled N-S component records, application a 10 min-width median filter to eliminate an effect of local seismic events and noise, and integration of the energy and normalization of daily En using an average coda amplitude from several regional earthquakes of M~5. A time-space distribution of En reveals a strong correlation between NVT energy release and 2006 SSE, which also replicates the two-phase character of this slow event and a migration of the slow slip maximum from North to South. There are also a few clear episodes of relatively high NVT energy release that do not correspond to any significant geodetic signal in GPS

  8. Quality parameters for a multimodal EEG/EMG/kinematic brain-computer interface (BCI aiming to suppress neurological tremor in upper limbs [v2; ref status: indexed, http://f1000r.es/3aq

    Directory of Open Access Journals (Sweden)

    Giuliana Grimaldi

    2014-04-01

    Full Text Available Tremor is the most common movement disorder encountered during daily neurological practice. Tremor in the upper limbs causes functional disability and social inconvenience, impairing daily life activities. The response of tremor to pharmacotherapy is variable. Therefore, a combination of drugs is often required. Surgery is considered when the response to medications is not sufficient. However, about one third of patients are refractory to current treatments. New bioengineering therapies are emerging as possible alternatives. Our study was carried out in the framework of the European project “Tremor” (ICT-2007-224051. The main purpose of this challenging project was to develop and validate a new treatment for upper limb tremor based on the combination of functional electrical stimulation (FES; which has been shown to reduce upper limb tremor with a brain-computer interface (BCI. A BCI-driven detection of voluntary movement is used to trigger FES in a closed-loop approach. Neurological tremor is detected using a matrix of EMG electrodes and inertial sensors embedded in a wearable textile. The identification of the intentionality of movement is a critical aspect to optimize this complex system. We propose a multimodal detection of the intentionality of movement by fusing signals from EEG, EMG and kinematic sensors (gyroscopes and accelerometry. Parameters of prediction of movement are extracted in order to provide global prediction plots and trigger FES properly. In particular, quality parameters (QPs for the EEG signals, corticomuscular coherence and event-related desynchronization/synchronization (ERD/ERS parameters are combined in an original algorithm which takes into account the refractoriness/responsiveness of tremor. A simulation study of the relationship between the threshold of ERD/ERS of artificial EEG traces and the QPs is also provided. Very interestingly, values of QPs were much greater than those obtained for the corticomuscular

  9. Hand-held electronic data collection and procedure environment

    International Nuclear Information System (INIS)

    Kennedy, E.; Doniz, K.

    1996-01-01

    As part of a CANDU Owners Group project, AECL has developed a hand-held electronic data collection and procedure environment. Integral to this environment is the C omputerized Procedure Engine . The development of the CPE allows operators, maintainers, and technical support staff to execute virtually any type of station procedure on a general-purpose PC-compatible hand-held computer. There are several advantages to using the computerized procedures: less paper use and handling, reduction in human error, reduction in rework in the field, an increase in procedural compliance, and immediate availability of data to download to databases and plant information systems. The paper describes: the advantages of using computerized procedures, why early forms of computerized procedures were inadequate, the features that the C omputerized Procedure Engine o ffers to the user, the streamlined life cycle of a computerized procedure, and field experience. The paper concludes that computerized procedures are ready for pilot applications at stations. (author)

  10. Handheld computers in nursing education: PDA pilot project.

    Science.gov (United States)

    Koeniger-Donohue, Rebecca

    2008-02-01

    Interest in the use and application of handheld technology at undergraduate and graduate nursing programs across the country is growing rapidly. Personal digital assistants (PDAs) are often referred to as a "peripheral brain" because they can save time, decrease errors, and simplify information retrieval at the point of care. In addition, research results support the notion that PDAs enhance nursing clinical education and are an effective student learning resource. However, most nursing programs lack the full range of technological resources to implement and provide ongoing support for handheld technology use by faculty and students. This article describes a 9-month pilot project for the initial use of PDAs by novice faculty and students at Simmons College.

  11. Handheld Multi-Gas Meters Market Survey Report

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Gustavious [Brigham Young Univ., Provo, UT (United States); Wald-Hopkins, Mark David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Obrey, Stephen J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Akhadov, Valida Dushdurova [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-23

    Handheld multi-gas meters (MGMs) are equipped with sensors to monitor oxygen (O2) levels and additional sensors to detect the presence of combustible or toxic gases in the environment. This report is limited to operational response-type MGMs that include at least four different sensors. These sensors can vary by type and by the chemical monitored. In real time, the sensors report the concentration of monitored gases in the atmosphere near the MGM. To provide emergency responders with information on handheld multi-gas meters, the System Assessment and Validation for Emergency Responders (SAVER) Program conducted a market survey. This market survey report is based on information gathered between November 2015 and February 2016 from vendors, Internet research, industry publications, an emergency responder focus group, and a government issued Request for Information (RFI) that was posted on the Federal Business Opportunities website.

  12. Volcanic tremor and local earthquakes at Copahue volcanic complex, Southern Andes, Argentina

    Science.gov (United States)

    Ibáñez, J. M.; Del Pezzo, E.; Bengoa, C.; Caselli, A.; Badi, G.; Almendros, J.

    2008-07-01

    In the present paper we describe the results of a seismic field survey carried out at Copahue Volcano, Southern Andes, Argentina, using a small-aperture, dense seismic antenna. Copahue Volcano is an active volcano that exhibited a few phreatic eruptions in the last 20 years. The aim of this experiment was to record and classify the background seismic activity of this volcanic area, and locate the sources of local earthquakes and volcanic tremor. Data consist of several volcano-tectonic (VT) earthquakes, and many samples of back-ground seismic noise. We use both ordinary spectral, and multi-spectral techniques to measure the spectral content, and an array technique [Zero Lag Cross Correlation technique] to measure the back-azimuth and apparent slowness of the signals propagating across the array. We locate VT earthquakes using a procedure based on the estimate of slowness vector components and S-P time. VT events are located mainly along the border of the Caviahue caldera lake, positioned at the South-East of Copahue volcano, in a depth interval of 1-3 km below the surface. The background noise shows the presence of many transients with high correlation among the array stations in the frequency band centered at 2.5 Hz. These transients are superimposed to an uncorrelated background seismic signal. Array solutions for these transients show a predominant slowness vector pointing to the exploited geothermal field of "Las Maquinitas" and "Copahue Village", located about 6 km north of the array site. We interpret this coherent signal as a tremor generated by the activity of the geothermal field.

  13. Genç erkek esansiyel tremor hastalarında anksiyete ve depresyon düzeyleri

    OpenAIRE

    Yaşar, Halit; Balıbey, Hakan; Tekeli, Hakan; Alay, Semih; Şenol, Mehmet Güney; Türker, Türker; Bayar, Nalan

    2014-01-01

    Objective: Essential tremor (ET), characterized by postural and kinetic tremor seen on hands and arms, is the most common movement disorder that causes significant disability. Besides the motor symptoms such as tremor, ET is also often accompanied by psychiatric symptoms such as anxiety and depression. We identified our objectives as to compare the level of anxiety and depression in young male patients with ET with the normal and to determine the relationship between this level and tremor sev...

  14. Interactive topology optimization on hand-held devices

    DEFF Research Database (Denmark)

    Aage, Niels; Nobel-Jørgensen, Morten; Andreasen, Casper Schousboe

    2013-01-01

    This paper presents an interactive topology optimization application designed for hand-held devices running iOS or Android. The TopOpt app solves the 2D minimum compliance problem with interactive control of load and support positions as well as volume fraction. Thus, it is possible to change......OS devices from the Apple App Store, at Google Play for the Android platform, and a web-version can be run from www.topopt.dtu.dk....

  15. Carbonaceous species emitted from handheld two-stroke engines

    Science.gov (United States)

    Volckens, John; Olson, David A.; Hays, Michael D.

    Small, handheld two-stroke engines used for lawn and garden work (e.g., string trimmers, leaf blowers, etc.) can emit a variety of potentially toxic carbonaceous air pollutants. Yet, the emissions effluents from these machines go largely uncharacterized, constraining the proper development of human exposure estimates, emissions inventories, and climate and air quality models. This study samples and evaluates chemical pollutant emissions from the dynamometer testing of six small, handheld spark-ignition engines—model years 1998-2002. Four oil-gas blends were tested in each engine in duplicate. Emissions of carbon dioxide, carbon monoxide, and gas-phase hydrocarbons were predominant, and the PM emitted was organic matter primarily. An ANOVA model determined that engine type and control tier contributed significantly to emissions variations across all identified compound classes; whereas fuel blend was an insignificant variable accounting for engines were generally intermediate in magnitude compared with other gasoline-powered engines, numerous compounds traditionally viewed as motor vehicle markers are also present in small engine emissions in similar relative proportions. Given that small, handheld two-stroke engines used for lawn and garden work account for 5-10% of total US emissions of CO, CO 2, NO x, HC, and PM 2.5, source apportionment models and human exposure studies need to consider the effect of these small engines on ambient concentrations in air polluted environments.

  16. A smartphone controlled handheld microfluidic liquid handling system.

    Science.gov (United States)

    Li, Baichen; Li, Lin; Guan, Allan; Dong, Quan; Ruan, Kangcheng; Hu, Ronggui; Li, Zhenyu

    2014-10-21

    Microfluidics and lab-on-a-chip technologies have made it possible to manipulate small volume liquids with unprecedented resolution, automation and integration. However, most current microfluidic systems still rely on bulky off-chip infrastructures such as compressed pressure sources, syringe pumps and computers to achieve complex liquid manipulation functions. Here, we present a handheld automated microfluidic liquid handling system controlled by a smartphone, which is enabled by combining elastomeric on-chip valves and a compact pneumatic system. As a demonstration, we show that the system can automatically perform all the liquid handling steps of a bead-based HIV1 p24 sandwich immunoassay on a multi-layer PDMS chip without any human intervention. The footprint of the system is 6 × 10.5 × 16.5 cm, and the total weight is 829 g including battery. Powered by a 12.8 V 1500 mAh Li battery, the system consumed 2.2 W on average during the immunoassay and lasted for 8.7 h. This handheld microfluidic liquid handling platform is generally applicable to many biochemical and cell-based assays requiring complex liquid manipulation and sample preparation steps such as FISH, PCR, flow cytometry and nucleic acid sequencing. In particular, the integration of this technology with read-out biosensors may help enable the realization of the long-sought Tricorder-like handheld in vitro diagnostic (IVD) systems.

  17. 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....

  18. Emotion modulation of the startle reflex in essential tremor: Blunted reactivity to unpleasant and pleasant pictures.

    Science.gov (United States)

    Lafo, Jacob A; Mikos, Ania; Mangal, Paul C; Scott, Bonnie M; Trifilio, Erin; Okun, Michael S; Bowers, Dawn

    2017-01-01

    Essential tremor is a highly prevalent movement disorder characterized by kinetic tremor and mild cognitive-executive changes. These features are commonly attributed to abnormal cerebellar changes, resulting in disruption of cerebellar-thalamo-cortical networks. Less attention has been paid to alterations in basic emotion processing in essential tremor, despite known cerebellar-limbic interconnectivity. In the current study, we tested the hypothesis that a psychophysiologic index of emotional reactivity, the emotion modulated startle reflex, would be muted in individuals with essential tremor relative to controls. Participants included 19 essential tremor patients and 18 controls, who viewed standard sets of unpleasant, pleasant, and neutral pictures for six seconds each. During picture viewing, white noise bursts were binaurally presented to elicit startle eyeblinks measured over the orbicularis oculi. Consistent with past literature, controls' startle eyeblink responses were modulated according to picture valence (unpleasant > neutral > pleasant). In essential tremor participants, startle eyeblinks were not modulated by emotion. This modulation failure was not due to medication effects, nor was it due to abnormal appraisal of emotional picture content. Neuroanatomically, it remains unclear whether diminished startle modulation in essential tremor is secondary to aberrant cerebellar input to the amygdala, which is involved in priming the startle response in emotional contexts, or due to more direct disruption between the cerebellum and brainstem startle circuitry. If the former is correct, these findings may be the first to reveal dysregulation of emotional networks in essential tremor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Multicentre European study of thalamic stimulation in parkinsonian and essential tremor

    NARCIS (Netherlands)

    Limousin, P.; Speelman, J. D.; Gielen, F.; Janssens, M.

    1999-01-01

    Thalamic stimulation has been proposed to treat disabling tremor. The aims of this multicentre study were to evaluate the efficacy and the morbidity of thalamic stimulation in a large number of patients with parkinsonian or essential tremor. One hundred and eleven patients were included in the study

  20. Wavelet coherence analysis: A new approach to distinguish organic and functional tremor types.

    Science.gov (United States)

    Kramer, G; Van der Stouwe, A M M; Maurits, N M; Tijssen, M A J; Elting, J W J

    2018-01-01

    To distinguish tremor subtypes using wavelet coherence analysis (WCA). WCA enables to detect variations in coherence and phase difference between two signals over time and might be especially useful in distinguishing functional from organic tremor. In this pilot study, polymyography recordings were studied retrospectively of 26 Parkinsonian (PT), 26 functional (FT), 26 essential (ET), and 20 enhanced physiological (EPT) tremor patients. Per patient one segment of 20 s in duration, in which tremor was present continuously in the same posture, was selected. We studied several coherence and phase related parameters, and analysed all possible muscle combinations of the flexor and extensor muscles of the upper and fore arm. The area under the receiver operating characteristic curve (AUC-ROC) was applied to compare WCA and standard coherence analysis to distinguish tremor subtypes. The percentage of time with significant coherence (PTSC) and the number of periods without significant coherence (NOV) proved the most discriminative parameters. FT could be discriminated from organic (PT, ET, EPT) tremor by high NOV (31.88 vs 21.58, 23.12 and 10.20 respectively) with an AUC-ROC of 0.809, while standard coherence analysis resulted in an AUC-ROC of 0.552. EMG-EMG WCA analysis might provide additional variables to distinguish functional from organic tremor. WCA might prove to be of additional value to discriminate between tremor types. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

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

    NARCIS (Netherlands)

    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

  2. Genetics Home Reference: fragile X-associated tremor/ataxia syndrome

    Science.gov (United States)

    ... Share: Email Facebook Twitter Home Health Conditions FXTAS Fragile X-associated tremor/ataxia syndrome Printable PDF Open All ... Javascript to view the expand/collapse boxes. Description Fragile X-associated tremor/ataxia syndrome ( FXTAS ) is characterized by ...

  3. Deep Brain Stimulation for Essential Tremor: Aligning Thalamic and Posterior Subthalamic Targets in 1 Surgical Trajectory

    NARCIS (Netherlands)

    Bot, Maarten; van Rootselaar, Fleur; Contarino, Maria Fiorella; Odekerken, Vincent; Dijk, Joke; de Bie, Rob; Schuurman, Richard; van den Munckhof, Pepijn

    2017-01-01

    Ventral intermediate nucleus (VIM) deep brain stimulation (DBS) and posterior subthalamic area (PSA) DBS suppress tremor in essential tremor (ET) patients, but it is not clear which target is optimal. Aligning both targets in 1 surgical trajectory would facilitate exploring stimulation of either

  4. Comprehensive, blinded assessment of balance in orthostatic tremor.

    Science.gov (United States)

    Bhatti, Danish; Thompson, Rebecca; Xia, Yiwen; Hellman, Amy; Schmaderer, Lorene; Suing, Katie; McKune, Jennifer; Penke, Cynthia; Iske, Regan; Roeder, Bobbi Jo; Siu, Ka-Chun; Bertoni, John M; Torres-Russotto, Diego

    2018-02-01

    Orthostatic Tremor (OT) is a movement disorder characterized by a sensation of unsteadiness and tremors in the 13-18 Hz range present upon standing. The pathophysiology of OT is not well understood but there is a relationship between the sensation of instability and leg tremors. Despite the sensation of unsteadiness, OT patients do not fall often and balance in OT has not been formally assessed. We present a prospective blinded study comparing balance assessment in patients with OT versus healthy controls. We prospectively enrolled 34 surface Electromyography (EMG)-confirmed primary OT subjects and 21 healthy controls. Participants underwent evaluations of balance by blinded physical therapists (PT) with standardized, validated, commonly used balance scales and tasks. OT subjects were mostly female (30/34, 88%) and controls were majority males (13/20, 65%). The average age of OT subjects was 68.5 years (range 54-87) and for controls was 69.4 (range 32-86). The average duration of OT symptoms was 18 years. OT subjects did significantly worse on all the balance scales and on most balance tasks including Berg Balance Scale, Functional Gait Assessment, Dynamic Gait Index, Unipedal Stance Test, Functional Reach Test and pull test. Gait speed and five times sit to stand were normal in OT. Common validated balance scales are significantly abnormal in primary OT. Despite the objective finding of impaired balance, OT patients do not commonly have falls. The reported sensation of unsteadiness in this patient population seems to be out of proportion to the number of actual falls. Further studies are needed to determine which components of commonly used balance scales are affected by a sensation of unsteadiness and fear of falling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Metabolic Hyperactivity of the Medial Posterior Parietal Lobes in Psychogenic Tremor

    Directory of Open Access Journals (Sweden)

    Peter Hedera

    2012-05-01

    Full Text Available Background: The pathophysiology of psychogenic movement disorders, including psychogenic tremor (PT, is only emerging. Case Report: This is a single case report of a patient who met diagnostic criteria for PT. He underwent positron emission tomography (PET of brain with 18F-deoxyglucose at resting state. His PET study showed symmetrically increased 18F-deoxyglucose uptake in both posterior medial parietal lobes. There was no corresponding abnormality on structural imaging. Discussion: Hypermetabolism of the medial aspects of posterior parietal lobes bilaterally may reflect abnormal activity of sensory integration that is important in the pathogenesis of PT. This further supports the idea that non-organic movement disorders may be associated with detectable functional brain abnormalities.

  6. Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor

    Science.gov (United States)

    Shelly, David R.

    2009-01-01

    Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high-quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid-2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short-term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ∼16 km beneath the eventual earthquake hypocenter.

  7. Bilateral cerebellar activation in unilaterally challenged essential tremor

    Directory of Open Access Journals (Sweden)

    Marja Broersma

    2016-01-01

    Conclusions: Our results expand on previous findings of bilateral cerebellar involvement in ET. We have identified specific areas in the bilateral somatomotor regions of the cerebellum: lobules V, VI and VIII.

  8. 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.

  9. Strength and Pain Threshold Handheld Dynamometry Test Reliability in Patellofemoral Pain.

    Science.gov (United States)

    van der Heijden, R A; Vollebregt, T; Bierma-Zeinstra, S M A; van Middelkoop, M

    2015-12-01

    Patellofemoral pain syndrome (PFPS), characterized by peri- and retropatellar pain, is a common disorder in young, active people. The etiology is unclear; however, quadriceps strength seems to be a contributing factor, and sensitization might play a role. The study purpose is determining the inter-rater reliability of handheld dynamometry to test both quadriceps strength and pressure pain threshold (PPT), a measure for sensitization, in patients with PFPS. This cross-sectional case-control study comprises 3 quadriceps strength and one PPT measurements performed by 2 independent investigators in 22 PFPS patients and 16 matched controls. Inter-rater reliability was analyzed using intraclass correlation coefficients (ICC) and Bland-Altman plots. Inter-rater reliability of quadriceps strength testing was fair to good in PFPS patients (ICC=0.72) and controls (ICC=0.63). Bland-Altman plots showed an increased difference between assessors when average quadriceps strength values exceeded 250 N. Inter-rater reliability of PPT was excellent in patients (ICC=0.79) and fair to good in controls (ICC=0.52). Handheld dynamometry seems to be a reliable method to test both quadriceps strength and PPT in PFPS patients. Inter-rater reliability was higher in PFPS patients compared to control subjects. With regard to quadriceps testing, a higher variance between assessors occurs when quadriceps strength increases. © Georg Thieme Verlag KG Stuttgart · New York.

  10. The use of handheld radiometry for the identification of stratigraphic characteristics of Paraiba Basin units

    International Nuclear Information System (INIS)

    Souza, Ebenezer Moreno de; Villar, Heldio Pereira; Lima, Ricardo de Andrade; Lima Filho, Mario

    2000-01-01

    A study on the use of radiometric techniques for the identification of stratigraphic characteristics of Paraiba Basin units was carried out with handheld instrumentation. The area chosen ran from north Pernambuco to south Paraiba. The presence of radioactive material had been previously determined. For this work a portable scintillometer was fixed to the door of a vehicle, on the outside, with the probe directed downwards. Background radiation was measured as 40 cps (counts per second). The scintillometer has an alarm which sounds whenever the measured count rate rises above a pre-established figure, 100 cps in the present case. Monitoring then proceeded manually. In sites where the count rate was much higher than 100 cps, the probe was lowered to the soil surface. Local coordinates were obtained by GPS. Therefore, an isoradioactivity map of the area could be drawn. The comparison between this map and local geological charts showed significant correlation between observed count rates and geologic formations. Low count rates were indicative of the Barreiras formation, whereas the highest rates were obtained for the Gramame formation (with urano-phosphatic lythotypes). It is concluded that handheld radiometry is a useful tool in geological charting, is special in areas where stratigraphic units have been masked by environmental changes and human activities. (author)

  11. 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.

  12. Different phase delays of peripheral input to primate motor cortex and spinal cord promote cancellation at physiological tremor frequencies.

    Science.gov (United States)

    Koželj, Saša; Baker, Stuart N

    2014-05-01

    Neurons in the spinal cord and motor cortex (M1) are partially phase-locked to cycles of physiological tremor, but with opposite phases. Convergence of spinal and cortical activity onto motoneurons may thus produce phase cancellation and a reduction in tremor amplitude. The mechanisms underlying this phase difference are unknown. We investigated coherence between spinal and M1 activity with sensory input. In two anesthetized monkeys, we electrically stimulated the medial, ulnar, deep radial, and superficial radial nerves; stimuli were timed as independent Poisson processes (rate 10 Hz). Single units were recorded from M1 (147 cells) or cervical spinal cord (61 cells). Ninety M1 cells were antidromically identified as pyramidal tract neurons (PTNs); M1 neurons were additionally classified according to M1 subdivision (rostral/caudal, M1r/c). Spike-stimulus coherence analysis revealed significant coupling over a broad range of frequencies, with the strongest coherence at <50 Hz. Delays implied by the slope of the coherence phase-frequency relationship were greater than the response onset latency, reflecting the importance of late response components for the transmission of oscillatory inputs. The spike-stimulus coherence phase over the 6-13 Hz physiological tremor band differed significantly between M1 and spinal cells (phase differences relative to the cord of 2.72 ± 0.29 and 1.72 ± 0.37 radians for PTNs from M1c and M1r, respectively). We conclude that different phases of the response to peripheral input could partially underlie antiphase M1 and spinal cord activity during motor behavior. The coordinated action of spinal and cortical feedback will act to reduce tremulous oscillations, possibly improving the overall stability and precision of motor control. Copyright © 2014 the American Physiological Society.

  13. Utilization of handheld computing to simplify compliance

    International Nuclear Information System (INIS)

    Galvin, G.; Rasmussen, J.; Haines, A.

    2008-01-01

    Monitoring job site performance and building a continually improving organization is an ongoing challenge for operators of process and power generation facilities. Stakeholders need to accurately capture records of quality and safety compliance, job progress, and operational experiences (OPEX). This paper explores the use of technology-enabled processes as a means for simplifying compliance to quality, safety, administrative, maintenance and operations activities. The discussion will explore a number of emerging technologies and their application to simplifying task execution and process compliance. This paper will further discuss methodologies to further refine processes through trending improvements in compliance and continually optimizing and simplifying through the use of technology. (author)

  14. Introducing handheld computing into a residency program: preliminary results from qualitative and quantitative inquiry.

    OpenAIRE

    Manning, B.; Gadd, C. S.

    2001-01-01

    Although published reports describe specific handheld computer applications in medical training, we know very little yet about how, and how well, handheld computing fits into the spectrum of information resources available for patient care and physician training. This paper reports preliminary quantitative and qualitative results from an evaluation study designed to track changes in computer usage patterns and computer-related attitudes before and after introduction of handheld computing. Pre...

  15. Neuroanatomical heterogeneity of essential tremor according to propranolol response.

    Directory of Open Access Journals (Sweden)

    Seok Jong Chung

    Full Text Available BACKGROUND: Recent studies have suggested that essential tremor (ET is a more complex and heterogeneous clinical entity than initially thought. In the present study, we assessed the pattern of cortical thickness and diffusion tensor white matter (WM changes in patients with ET according to the response to propranolol to explore the pathogenesis underlying the clinical heterogeneity of ET. METHODS: A total of 32 patients with drug naive ET were recruited prospectively from the Movement Disorders outpatient clinic. The patients were divided into a propranolol-responder group (n = 18 and a non-responder group (n = 14. We analyzed the pattern of cortical thickness and diffusion tensor WM changes between these two groups and performed correlation analysis between imaging and clinical parameters. RESULTS: There were no significant differences in demographic characteristics, general cognition, or results of detailed neuropsychological tests between the groups. The non-responder group showed more severe cortical atrophy in the left orbitofrontal cortex and right temporal cortex relative to responders. However, the responders exhibited significantly lower fractional anisotropy values in the bilateral frontal, corpus callosal, and right parietotemporal WM compared with the non-responder group. There were no significant clusters where the cortical thickness or WM alterations were significantly correlated with initial tremor severity or disease duration. CONCLUSIONS: The present data suggest that patients with ET have heterogeneous cortical thinning and WM alteration with respect to responsiveness to propranolol, suggesting that propranolol responsiveness may be a predictive factor to determine ET subtypes in terms of neuroanatomical heterogeneity.

  16. Linking Essential Tremor to the Cerebellum-Neuroimaging Evidence.

    Science.gov (United States)

    Cerasa, Antonio; Quattrone, Aldo

    2016-06-01

    Essential tremor (ET) is the most common pathological tremor disorder in the world, and post-mortem evidence has shown that the cerebellum is the most consistent area of pathology in ET. In the last few years, advanced neuroimaging has tried to confirm this evidence. The aim of the present review is to discuss to what extent the evidence provided by this field of study may be generalised. We performed a systematic literature search combining the terms ET with the following keywords: MRI, VBM, MRS, DTI, fMRI, PET and SPECT. We summarised and discussed each study and placed the results in the context of existing knowledge regarding the cerebellar involvement in ET. A total of 51 neuroimaging studies met our search criteria, roughly divided into 19 structural and 32 functional studies. Despite clinical and methodological differences, both functional and structural imaging studies showed similar findings but without defining a clear topography of neurodegeneration. Indeed, the vast majority of studies found functional and structural abnormalities in several parts of the anterior and posterior cerebellar lobules, but it remains to be established to what degree these neural changes contribute to clinical symptoms of ET. Currently, advanced neuroimaging has confirmed the involvement of the cerebellum in pathophysiological processes of ET, although a high variability in results persists. For this reason, the translation of this knowledge into daily clinical practice is again partially limited, although new advanced multivariate neuroimaging approaches (machine-learning) are proving interesting changes of perspective.

  17. 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 relationship to Parkinson disease.

  18. Adaptation of feedforward movement control is abnormal in patients with cervical dystonia and tremor.

    Science.gov (United States)

    Avanzino, Laura; Ravaschio, Andrea; Lagravinese, Giovanna; Bonassi, Gaia; Abbruzzese, Giovanni; Pelosin, Elisa

    2018-01-01

    It is under debate whether the cerebellum plays a role in dystonia pathophysiology and in the expression of clinical phenotypes. We investigated a typical cerebellar function (anticipatory movement control) in patients with cervical dystonia (CD) with and without tremor. Twenty patients with CD, with and without tremor, and 17 healthy controls were required to catch balls of different load: 15 trials with a light ball, 25 trials with a heavy ball (adaptation) and 15 trials with a light ball (post-adaptation). Arm movements were recorded using a motion capture system. We evaluated: (i) the anticipatory adjustment (just before the impact); (ii) the extent and rate of the adaptation (at the impact) and (iii) the aftereffect in the post-adaptation phase. The anticipatory adjustment was reduced during adaptation in CD patients with tremor respect to CD patients without tremor and controls. The extent and rate of adaptation and the aftereffect in the post-adaptation phase were smaller in CD with tremor than in controls and CD without tremor. Patients with cervical dystonia and tremor display an abnormal predictive movement control. Our findings point to a possible role of cerebellum in the expression of a clinical phenotype in dystonia. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  19. 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.)

  20. Wrist sensor-based tremor severity quantification in Parkinson's disease using convolutional neural network.

    Science.gov (United States)

    Kim, Han Byul; Lee, Woong Woo; Kim, Aryun; Lee, Hong Ji; Park, Hye Young; Jeon, Hyo Seon; Kim, Sang Kyong; Jeon, Beomseok; Park, Kwang S

    2018-04-01

    Tremor is a commonly observed symptom in patients of Parkinson's disease (PD), and accurate measurement of tremor severity is essential in prescribing appropriate treatment to relieve its symptoms. We propose a tremor assessment system based on the use of a convolutional neural network (CNN) to differentiate the severity of symptoms as measured in data collected from a wearable device. Tremor signals were recorded from 92 PD patients using a custom-developed device (SNUMAP) equipped with an accelerometer and gyroscope mounted on a wrist module. Neurologists assessed the tremor symptoms on the Unified Parkinson's Disease Rating Scale (UPDRS) from simultaneously recorded video footages. The measured data were transformed into the frequency domain and used to construct a two-dimensional image for training the network, and the CNN model was trained by convolving tremor signal images with kernels. The proposed CNN architecture was compared to previously studied machine learning algorithms and found to outperform them (accuracy = 0.85, linear weighted kappa = 0.85). More precise monitoring of PD tremor symptoms in daily life could be possible using our proposed method. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Irene Aicua

    2014-10-01

    Full Text Available 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.

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

    International Nuclear Information System (INIS)

    Lenka, Abhishek; Bhalsing, Ketaki Swapnil; Jhunjhunwala, Ketan; Panda, Rajanikant; Saini, Jitender; Bharath, Rose Dawn; Naduthota, Rajini M.; Yadav, Ravi; Pal, Pramod Kumar

    2017-01-01

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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

    2016-10-04

    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.

  5. A hand-held robotic device for peripheral intravenous catheterization.

    Science.gov (United States)

    Cheng, Zhuoqi; Davies, Brian L; Caldwell, Darwin G; Barresi, Giacinto; Xu, Qinqi; Mattos, Leonardo S

    2017-12-01

    Intravenous catheterization is frequently required for numerous medical treatments. However, this process is characterized by a high failure rate, especially when performed on difficult patients such as newborns and infants. Very young patients have small veins, and that increases the chances of accidentally puncturing the catheterization needle directly through them. In this article, we present the design, development and experimental evaluation of a novel hand-held robotic device for improving the process of peripheral intravenous catheterization by facilitating the needle insertion procedure. To our knowledge, this design is the first hand-held robotic device for assisting in the catheterization insertion task. Compared to the other available technologies, it has several unique advantages such as being compact, low-cost and able to reliably detect venipuncture. The system is equipped with an electrical impedance sensor at the tip of the catheterization needle, which provides real-time measurements used to supervise and control the catheter insertion process. This allows the robotic system to precisely position the needle within the lumen of the target vein, leading to enhanced catheterization success rate. Experiments conducted to evaluate the device demonstrated that it is also effective to deskill the task. Naïve subjects achieved an average catheterization success rate of 88% on a 1.5 mm phantom vessel with the robotic device versus 12% with the traditional unassisted system. The results of this work prove the feasibility of a hand-held assistive robotic device for intravenous catheterization and show that such device has the potential to greatly improve the success rate of these difficult operations.

  6. Biomechanical Loading as an Alternative Treatment for Tremor: A Review of Two Approaches

    Directory of Open Access Journals (Sweden)

    Eduardo Rocon

    2012-10-01

    Full Text Available Background: Tremor is the most common movement disorder and strongly increases in incidence and prevalence with aging. Although not life threatening, upper-limb tremors hamper the independence of 65% of people suffering from them affected persons, greatly impacting their quality of life. Current treatments include pharmacotherapy and surgery (thalamotomy and deep brain stimulation. However, these options are not sufficient for approximately 25% of patients. Therefore, further research and new therapeutic options are required to effectively manage pathological tremor.Methods: This paper presents findings of two research projects in which two different wearable robots for tremor management were developed based on force loading and validated. The first consisted of a robotic exoskeleton that applied forces to tremulous limbs and consistently attenuated mild and severe tremors. The second was a neuroprosthesis based on transcutaneous neurostimulation. A total of 22 patients suffering from parkinsonian or essential tremor (ET of different severities were recruited for experimental validation, and both systems were evaluated using standard tasks employed for neurological examination. The inclusion criterion was a postural and/or kinetic pathological upper-limb tremor resistant to medication.Results: The results demonstrate that both approaches effectively suppressed tremor in most patients, although further research is required. The work presented here is based on clinical evidence from a small number of patients (n = 10 for robotic exoskeleton and n = 12 for the neuroprosthesis, but most had a positive response to the approaches. In summary, biomechanical loading is non-invasive and painless. It may be effective in patients who are insufficiently responsive (or have adverse reactions to drugs or in whom surgery is contraindicated.Discussion: This paper identifies and evaluates biomechanical loading approaches to tremor management and

  7. Linear and nonlinear tremor acceleration characteristics in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Meigal, A Yu; Rissanen, S M; Airaksinen, O; Tarvainen, M P; Georgiadis, S D; Karjalainen, P A; Kankaanpää, M

    2012-01-01

    The purpose of the study was to evaluate linear and nonlinear tremor characteristics of the hand in patients with Parkinson's disease (PD) and to compare the results with those of healthy old and young control subjects. Furthermore, the aim was to study correlation between tremor characteristics and clinical signs. A variety of nonlinear (sample entropy, cross-sample entropy, recurrence rate, determinism and correlation dimension) and linear (amplitude, spectral peak frequency and total power, and coherence) hand tremor parameters were computed from acceleration measurements for PD patients (n = 30, 68.3 ± 7.8 years), and old (n = 20, 64.2 ± 7.0 years) and young (n = 20, 18.4 ± 1.1 years) control subjects. Nonlinear tremor parameters such as determinism, sample entropy and cross-sample entropy were significantly different between the PD patients and healthy controls. These parameters correlated with the Unified Parkinson's disease rating scale (UPDRS), tremor and finger tapping scores, but not with the rigidity scores. Linear tremor parameters such as the amplitude and the maximum power (power corresponding to peak frequency) also correlated with the clinical findings. No major difference was detected in the tremor characteristics between old and young control subjects. The study revealed that tremor in PD patients is more deterministic and regular when compared to old or young healthy controls. The nonlinear tremor parameters can differentiate patients with PD from healthy control subjects and these parameters may have potential in the assessment of the severity of PD (UPDRS). (paper)

  8. Illicit stimulant use in humans is associated with a long-term increase in tremor.

    Directory of Open Access Journals (Sweden)

    Stanley C Flavel

    Full Text Available Use of illicit stimulants such as methamphetamine, cocaine, and ecstasy is a significant health problem. The United Nations Office on Drugs and Crime estimates that 14-57 million people use stimulants each year. Chronic use of illicit stimulants can cause neurotoxicity in animals and humans but the long-term functional consequences are not well understood. Stimulant users self-report problems with tremor whilst abstinent. Thus, the aim of the current study was to investigate the long-term effect of stimulant use on human tremor during rest and movement. We hypothesized that individuals with a history of stimulant use would exhibit abnormally large tremor during rest and movement. Tremor was assessed in abstinent ecstasy users (n = 9; 22 ± 3 yrs and abstinent users of amphetamine-like drugs (n = 7; 33 ± 9 yrs and in two control groups: non-drug users (n = 23; 27 ± 8 yrs and cannabis users (n = 12; 24 ± 7 yrs. Tremor was measured with an accelerometer attached to the index finger at rest (30 s and during flexion and extension of the index finger (30 s. Acceleration traces were analyzed with fast-Fourier transform. During movement, tremor amplitude was significantly greater in ecstasy users than in non-drug users (frequency range 3.9-13.3 Hz; P<0.05, but was unaffected in cannabis users or users of amphetamine-like drugs. The peak frequency of tremor did not significantly differ between groups nor did resting tremor. In conclusion, abstinent ecstasy users exhibit an abnormally large tremor during movement. Further work is required to determine if the abnormality translates to increased risk of movement disorders in this population.

  9. Interarytenoid muscle botox injection for treatment of adductor spasmodic dysphonia with vocal tremor.

    Science.gov (United States)

    Kendall, Katherine A; Leonard, Rebecca J

    2011-01-01

    Up to one-third of patients presenting with adductor spasmodic dysphonia will have an associated vocal tremor. These patients may not respond fully to treatment using thyroarytenoid (TA) muscle botulinum toxin (Botox) injection. Treatment failures are attributed to the involvement of multiple muscle groups in the tremor. This study evaluates the results of combined interarytenoid (IA) and TA muscle Botox injection in a group of 27 patients with adductor spasmodic dysphonia and vocal tremor and in four patients with severe vocal tremor alone. Patient-satisfaction data were reviewed retrospectively. Pre- and postinjection acoustic data were collected prospectively. Acoustic measures of fundamental frequency and cycle-by-cycle variability in frequency (jitter) and intensity (shimmer) were obtained from 15 patients' sustained vowel productions. Measures were collected after TA muscle injection, alone, and after combined TA and IA (TA+IA) muscle injections. In addition, two experienced voice clinicians blindly assessed tremor severity from recordings made for each patient in the two conditions. Patients were also queried regarding their satisfaction with the results of the injections and whether they desired to continue receiving TA+IA treatment. Significant improvement in all acoustic measures except for % jitter was observed after the TA+IA muscle injections. Listeners identified voice samples after TA+IA muscle injections as demonstrating less tremor in 73% of the paired comparisons. Sixty-seven percent of the patients with spasmodic dysphonia and vocal tremor wished to continue to receive IA muscle injections. Only one patient with severe vocal tremor wished to continue with injections. The addition of an IA muscle Botox injection to the treatment of patients with a combination adductor spasmodic dysphonia and vocal tremor may improve voice outcomes. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  10. What many years of tremor reveals about the Mexican Sweet Spot

    Science.gov (United States)

    Husker, A. L.; Avila, L.; Gonzalez, G.; Frank, W.; Kostoglodov, V.

    2017-12-01

    Different temporary seismic deployments have detected and located tectonic tremor in Mexico. These different temporary studies have lasted for a maximum of a few years. However, the long-term SSE's occur every 4 years. The permanent network is too sparse to locate SSEs, however one station is located in the main tremor region and has very low noise. We use spectral detection to create a catalog from its installation in March 2009 to the present. The catalog corresponds with the catalog determined during the temporary GGAP seismic network deployment, which gives us confidence that the single station detection works. Two separate large long term SSEs (2009-2010 and 2014) occur in this time span. We find a good correlation between the tremor and slip at the beginning of the SSEs. However, we find differences in both in the later stages of the SSEs. The 2009-2010 SSE appeared to be ending towards the end of 2009, however it was reactivated by the Feb. 27, 2010 M8.8 Chilean earthquake. The tremor showed a small many day burst (similar to other bursts) associated with the earthquake, but did not resume the high continuous tremor rate associated with the beginning of the SSE or seen during other large SSEs. The tremor rate at the end of the 2014 SSE stayed high for many months after the SSE and did not return to the background inter-SSE rate until the middle of 2015, about 6 months after the SSE ended. The background tremor rate is roughly 1 hour/day and remains constant over the entire period. This rate is actually comprised of many bursts that can last for up to 2 weeks with up to 80 hours of tremor during that time. The very constant long-term tremor rate made up of bursts can be explained by a simple stick-slip model.

  11. Adaptive RF front-ends for hand-held applications

    CERN Document Server

    van Bezooijen, Andre; van Roermund, Arthur

    2010-01-01

    The RF front-end - antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable. ""Adaptive RF Front-Ends for Hand-Held Applications"" presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control,

  12. Absorption Related to Hand-Held Devices in Data Mode

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Nielsen, Jesper Ødum; Pedersen, Gert F.

    2016-01-01

    The human body has an influence on the radiation from handheld devices like smartphones, tablets and laptops, part of the energy is absorbed and the spatial distribution of the radiated part is modified. Previous studies of whole body absorp- tion have mainly been numerical or related to talk mode....... In the present paper an experimental study involving four volunteers and three different devices is performed from 0.5 to 3 GHz. The devices are a laptop, a tablet, and a smartphone all held in the lap. The 3D distribution of radiation is measured. Comparing the integrated power in the case of a person present...

  13. Development of dual sensor hand-held detector

    Science.gov (United States)

    Sezgin, Mehmet

    2010-04-01

    In this paper hand-held dual sensor detector development requirements are considered dedicated to buried object detection. Design characteristics of such a system are categorized and listed. Hardware and software structures, ergonomics, user interface, environmental and EMC/EMI tests to be applied and performance test issues are studied. Main properties of the developed system (SEZER) are presented, which contains Metal Detector (MD) and Ground Penetrating Radar (GPR). The realized system has ergonomic structure and can detect both metallic and non-metallic buried objects. Moreover classification of target is possible if it was defined to the signal processing software in learning phase.

  14. Fast, cheap and in control: spectral imaging with handheld devices

    Science.gov (United States)

    Gooding, Edward A.; Deutsch, Erik R.; Huehnerhoff, Joseph; Hajian, Arsen R.

    2017-05-01

    Remote sensing has moved out of the laboratory and into the real world. Instruments using reflection or Raman imaging modalities become faster, cheaper and more powerful annually. Enabling technologies include virtual slit spectrometer design, high power multimode diode lasers, fast open-loop scanning systems, low-noise IR-sensitive array detectors and low-cost computers with touchscreen interfaces. High-volume manufacturing assembles these components into inexpensive portable or handheld devices that make possible sophisticated decision-making based on robust data analytics. Examples include threat, hazmat and narcotics detection; remote gas sensing; biophotonic screening; environmental remediation and a host of other applications.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Functional magnetic resonance imaging in primary writing tremor and writer’s cramp: A pilot study

    Science.gov (United States)

    Sahni, Hirdesh; Jayakumar, Peruvumba N.; Pal, Pramod Kumar

    2010-01-01

    Objectives: The precise pathophysiology of primary writing tremor (PWT) and writer’s cramp (WC) is not known. The aim of this study is to compare the cerebral activation patterns in patients of PWT, WC and healthy controls, during a task of signing on paper, using functional magnetic resonance imaging (fMRI). Materials and Methods: Six subjects with PWT, three with WC and six healthy volunteers were examined using a 1.5-Tesla scanner. The paradigm consisted of three times repetition of a set of period of rest and activity. Each set consisted of 10 blood oxygen level dependent (BOLD) echo-planar imaging (EPI) acquisitions at rest followed by 10 BOLD EPI acquisitions while signing their names on paper using the dominant right hand. Entire brain was covered. SPM99 analysis was done. Results: In comparison to the healthy controls, the following differences in cerebral activation were noted in the patients: (a) primary and supplementary motor areas showed overactivation in patients of PWT and underactivation in patients of WC, (b) the cingulate motor area showed underactivation in patients of PWT and overactivation in patients of WC and (c) the cerebellar activity was reduced in both WC and PWT. Conclusion: Our preliminary findings suggest that the cerebral and cerebellar activation patterns in PWT and WC during signing on paper are distinct from each other and from healthy controls. There may be cerebellar dysfunction in addition to motor dysfunctions in the pathogenesis of these disorders. PMID:21085530

  17. Probabilistic mapping of deep brain stimulation effects in essential tremor

    Directory of Open Access Journals (Sweden)

    Till A Dembek

    2017-01-01

    Discussion: Our results support the assumption, that the ZI might be a very effective target for tremor suppression. However stimulation inside the ZI and in its close vicinity was also related to the occurrence of stimulation-induced side-effects, so it remains unclear whether the VIM or the ZI is the overall better target. The study demonstrates the use of PSMs for target selection and evaluation. While their accuracy has to be carefully discussed, they can improve the understanding of DBS effects and can be of use for other DBS targets in the therapy of neurological or psychiatric disorders as well. Furthermore they provide a priori information about expected DBS effects in a certain region and might be helpful to clinicians in programming DBS devices in the future.

  18. The Complimentary Role of Methoxy-Isobutyl-Isonitrile and Hand-Held Gamma Probe in Adamantinoma

    Science.gov (United States)

    Maharaj, Masha; Korowlay, Nisaar; Ellmann, Prof

    2016-01-01

    Adamantinoma is a rare locally aggressive osteolytic tumor that is found 90% of the time in the diaphysis of the tibia with the remaining lesions found in the fibula and long tubular bones. A case of adamantinoma of the tibia is presented. The added value of nuclear medicine investigations in the workup of this patient is described. A three-phase whole body 99mTc-methylene diphosphonate bone and a whole body 99mTc-methoxy-isobutyl-isonitrile scans were complimentary in the demarcation of viable bone tumor and the assessment of the remainder of the bone and soft tissue to exclude other sites. Intra-operative assistance with a hand-held gamma probe, guided the biopsy of the most metabolically active tumor tissue. Histology revealed a biphasic tumor composed of epithelial and fibrous components, in keeping with an adamantinoma. PMID:26912979

  19. Clinical assessment of hip strength using a hand-held dynamometer is reliable

    DEFF Research Database (Denmark)

    Thorborg, K; Petersen, J; Magnusson, S P

    2010-01-01

    rotation (ER), internal rotation (IR), flexion (FLEX) and extension (EXT) using a hand-held dynamometer. Nine subjects (five males, four females), physically active for at least 2.5 h a week, were included. Twelve standardized isometric strength tests were performed twice with a 1-week interval in between......Hip strength assessment plays an important role in the clinical examination of the hip and groin region. The primary aim of this study was to examine the absolute test-retest measurement variation concerning standardized strength assessments of hip abduction (ABD), adduction (ADD), external...... by the same examiner. The test order was randomized to avoid systematic bias. Measurement variation between sessions was 3-12%. When the maximum value of four measurements was used, test-retest measurement variation was below 10% in 11 of the 12 individual hip strength tests and below 5% in five of the 12...

  20. THE ADOPTION OF THE ARCGIS SYSTEM TO SUPPORT THE ANALYSES OF THE INFLUENCE OF THE MINING TREMORS ON THE BUILDING OBJECTS

    Directory of Open Access Journals (Sweden)

    Violetta SOKOŁA-SZEWIOŁA

    2016-10-01

    Full Text Available Nowadays the mining companies use the Spatial Information System in order to facilitate data management, gathered during the mining activity. For these purposes various kinds of applications and software information are used. They allow for faster and easier data processing. In the paper there are presented the possibilities of using the ArcGIS system to support the tasks performed in the mining industry in the scope of the analysis of the influence of the mining tremors, induced by the longwall exploitation on the facilities construction sited on the surface area. These possibilities are presented by the example of the database developed for the coal mine KWK “Rydułtowy-Anna.” The developed database was created using ArcGIS software for Desktop 10. 1. It contains the values of parameters, specified for its implementation relevant to the analyses of the influence of the mining tremors on the surface structures.

  1. A hand-held beta imaging probe for FDG.

    Science.gov (United States)

    Singh, Bipin; Stack, Brendan C; Thacker, Samta; Gaysinskiy, Valeriy; Bartel, Twyla; Lowe, Val; Cool, Steven; Entine, Gerald; Nagarkar, Vivek

    2013-04-01

    Advances in radiopharmaceuticals and clinical understanding have escalated the use of intraoperative gamma probes in surgery. However, most probes on the market are non-imaging gamma probes that suffer from the lack of ancillary information of the surveyed tissue area. We have developed a novel, hand-held digital Imaging Beta Probe™ (IBP™) to be used in surgery in conjunction with beta-emitting radiopharmaceuticals such as (18)FDG, (131)I and (32)P for real-time imaging of a surveyed area with higher spatial resolution and sensitivity and greater convenience than existing instruments. We describe the design and validation of a hand-held beta probe intended to be used as a visual mapping device to locate and confirm excision of (18)FDG-avid primary tumors and metastases in an animal model. We have demonstrated a device which can generate beta images from (18)FDG avid lesions in an animal model. It is feasible to image beta irradiation in animal models of cancer given (18)FDG. This technology may be applied to clinical mapping of tumors and/or their metastases in the operating room. Visual image depiction of malignancy may aid the surgeon in localization and excision of lesions of interest.

  2. An Investigation of Game-Embedded Handheld Devices to Enhance English Learning

    Science.gov (United States)

    Hung, Hui-Chun; Young, Shelley Shwu-Ching

    2015-01-01

    This study proposed and implemented a system combining the advantages of both educational games and wireless handheld technology to promote the interactive English learning in the classroom setting. An interactive English vocabulary acquisition board game was designed with the system being implemented on handheld devices. Thirty sixth-grade…

  3. My-Mini-Pet: A Handheld Pet-Nurturing Game to Engage Students in Arithmetic Practices

    Science.gov (United States)

    Liao, C. C. Y.; Chen, Z-H.; Cheng, H. N. H.; Chen, F-C.; Chan, T-W.

    2011-01-01

    In the last decade, more and more games have been developed for handheld devices. Furthermore, the popularity of handheld devices and increase of wireless computing can be taken advantage of to provide students with more learning opportunities. Games also could bring promising benefits--specifically, motivating students to learn/play, sustaining…

  4. 75 FR 27504 - Substantial Product Hazard List: Hand-Held Hair Dryers

    Science.gov (United States)

    2010-05-17

    ... immersion during their use. Section 15(a) of the CPSA defines ``substantial product hazard'' to include, a....'' Hand-held hair dryers routinely contain open-coil heating elements that are, in essence, uninsulated..., bathtub, or lavatory). The proposed rule would define ``hand-held hair dryer'' as ``an electrical...

  5. 40 CFR 90.129 - Fuel tank permeation from handheld engines and equipment.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel tank permeation from handheld... KILOWATTS Emission Standards and Certification Provisions § 90.129 Fuel tank permeation from handheld... equipment with respect to fuel tanks. For the purposes of this section, fuel tanks do not include fuel caps...

  6. The impact of legislation in Ireland on handheld mobile phone use by drivers.

    LENUS (Irish Health Repository)

    O'Meara, M

    2008-01-01

    Under the Road Traffic Act, 2006 handheld mobile phone use whilst driving is an offence liable to a fine and penalty points. The aim of this study was to determine whether there has been a change in driver behaviour following the introduction of this legislation. This study found that 2.3% of drivers were still using a handheld mobile phone.

  7. Evaluation of an enclosed ultraviolet-C radiation device for decontamination of mobile handheld devices.

    Science.gov (United States)

    Mathew, J Itty; Cadnum, Jennifer L; Sankar, Thriveen; Jencson, Annette L; Kundrapu, Sirisha; Donskey, Curtis J

    2016-06-01

    Mobile handheld devices used in health care settings may become contaminated with health care-associated pathogens. We demonstrated that an enclosed ultraviolet-C radiation device was effective in rapidly reducing methicillin-resistant Staphylococcus aureus, and with longer exposure times, Clostridium difficile spores, on glass slides and reducing contamination on in-use mobile handheld devices. Published by Elsevier Inc.

  8. Eyeblink conditioning is impaired in subjects with essential tremor.

    Science.gov (United States)

    Kronenbuerger, Martin; Gerwig, Marcus; Brol, Beate; Block, Frank; Timmann, Dagmar

    2007-06-01

    Several lines of evidence point to an involvement of the olivo-cerebellar system in the pathogenesis of essential tremor (ET), with clinical signs of cerebellar dysfunction being present in some subjects in the advanced stage. Besides motor coordination, the cerebellum is critically involved in motor learning. Evidence of motor learning deficits would strengthen the hypothesis of olivo-cerebellar involvement in ET. Conditioning of the eyeblink reflex is a well-established paradigm to assess motor learning. Twenty-three ET subjects (13 males, 10 females; mean age 44.3 +/- 22.3 years, mean disease duration 17.4 +/- 17.3 years) and 23 age-matched healthy controls were studied on two consecutive days using a standard delay eyeblink conditioning protocol. Six ET subjects exhibited accompanying clinical signs of cerebellar dysfunction. Care was taken to examine subjects without medication affecting central nervous functioning. Seven ET subjects and three controls on low-dose beta-blocker treatments, which had no effect on eyeblink conditioning in animal studies, were allowed into the study. The ability to acquire conditioned eyeblink responses was significantly reduced in ET subjects compared with controls. Impairment of eyeblink conditioning was not due to low-dose beta-blocker medication. Additionally, acquisition of conditioned eyeblink response was reduced in ET subjects regardless of the presence of cerebellar signs in clinical examination. There were no differences in timing or extinction of conditioned responses between groups and conditioning deficits did not correlate with the degree of tremor or ataxia as rated by clinical scores. The findings of disordered eyeblink conditioning support the hypothesis that ET is caused by a functional disturbance of olivo-cerebellar circuits which may cause cerebellar dysfunction. In particular, results point to an involvement of the olivo-cerebellar system in early stages of ET.

  9. The effect of N.A. Bernstein in the evaluation of tremor parameters for different acoustic effects

    Directory of Open Access Journals (Sweden)

    Valery M. Eskov

    2015-12-01

    Full Text Available The reaction of the regulatory systems of the neuromuscular system of the human to the various acoustic effects (white noise, rhythmic music, classical music, hard rock using special methods (e.g. chaos theory, self-organization and methods of conventional statistics was studied. The state of hearing with or without acoustic impact is studied. However, the approach used is based on the analysis of the quasi-attractors parameters of the neuromuscular system (postural tremor with simultaneous registration of left and right hand tremorogramm (in terms of sound effects. Acoustic effects played a role of a disturbing factor for tremor regulation (and muscle activity; it changes the psychophysiological state of the subject (N.A. Bernstein C and D regulation system. The designed matrix method of analysis enables the identification of systems with chaotic organization that was shown in this work by comparing left and right hand tremorogramm of subjects at different acoustic effects. The acoustic effects are regarded as disturbing influences affecting the mental state of homeostasis. In this case the main task is a quantitative assessment of mental status test calculations by tremorogramm parameters. Quasi-attractor parameters calculation method demonstrates the differences in tremorogramm of left and right hands and tremor responses to acoustic feedback. This employs a new approach in the evaluation of motor asymmetry and the method of recording the parameters of mental homeostasis by tremorogramm of chaotic dynamics. The problem of registering human mental status in cognitive psychology is resolved with a high degree of uncertainty (Bernstein. The acoustic effects are considered as disturbance affecting the mental state of homeostasis. In this case the main task is to hold a quantitative assessment of the mental state by means of calculating tremorogramm parameters. A method for calculating quasi-attractor parameters, which shows differences in left

  10. The effects of Thalamic Deep Brain Stimulation on speech dynamics in patients with Essential Tremor: An articulographic study.

    Directory of Open Access Journals (Sweden)

    Doris Mücke

    Full Text Available Acoustic studies have revealed that patients with Essential Tremor treated with thalamic Deep Brain Stimulation (DBS may suffer from speech deterioration in terms of imprecise oral articulation and reduced voicing control. Based on the acoustic signal one cannot infer, however, whether this deterioration is due to a general slowing down of the speech motor system (e.g., a target undershoot of a desired articulatory goal resulting from being too slow or disturbed coordination (e.g., a target undershoot caused by problems with the relative phasing of articulatory movements. To elucidate this issue further, we here investigated both acoustics and articulatory patterns of the labial and lingual system using Electromagnetic Articulography (EMA in twelve Essential Tremor patients treated with thalamic DBS and twelve age- and sex-matched controls. By comparing patients with activated (DBS-ON and inactivated stimulation (DBS-OFF with control speakers, we show that critical changes in speech dynamics occur on two levels: With inactivated stimulation (DBS-OFF, patients showed coordination problems of the labial and lingual system in terms of articulatory imprecision and slowness. These effects of articulatory discoordination worsened under activated stimulation, accompanied by an additional overall slowing down of the speech motor system. This leads to a poor performance of syllables on the acoustic surface, reflecting an aggravation either of pre-existing cerebellar deficits and/or the affection of the upper motor fibers of the internal capsule.

  11. Large Contrast Between the Moment Magnitude of Tremor and the Moment Magnitude of Slip in ETS Events

    Science.gov (United States)

    Kao, H.; Wang, K.; Dragert, H.; Rogers, G. C.; Kao, J. Y.

    2009-12-01

    We have developed an algorithm to estimate the moment magnitudes (Mw) of seismic tremors that are recorded during episodic tremor and slip (ETS) events beneath the northern Cascadia margin. The tremor “cloud” during an ETS episode consists of numerous individual tremor bursts. For each tremor burst, the hypocenter is first determined by the Source-Scanning Algorithm [Kao and Shan, 2004]. From the derived source location, we calculate a set of synthetic seismograms for each station based on a fixed seismic moment but different focal mechanisms. The maximum tremor amplitude observed at each station is then compared to that of the synthetics to give an estimate of the corresponding seismic moment of the tremor burst. The seismic moment averaged over all stations is used to calculate the final tremor burst Mw. We have applied this method to local earthquakes for calibration and the results are very consistent with the magnitudes listed in the catalogue. For each of the 8 northern Cascadia ETS episodes whose GPS coverage is sufficient for slip distribution inversion, the cumulative tremor Mw for the entire tremor cloud, determined from the combined moments of all individual tremor bursts in the ETS episode, is ~3 orders less than the corresponding slip Mw in the same episode (e.g., 3.7 vs. 6.7). This result suggests that aseismic slip is the predominant mode of deformation during ETS. The majority of individual tremor bursts in northern Cascadia have Mw ranging between 1.0 and 1.7 with the mean of 1.34. Only 5% of all tremors are larger than 2.0 with the largest being ~2.5.

  12. Effect of propranolol in head tremor: quantitative study following single-dose and sustained drug administration.

    Science.gov (United States)

    Calzetti, S; Sasso, E; Negrotti, A; Baratti, M; Fava, R

    1992-12-01

    The effect of the beta-adrenoceptor antagonist propranolol has been investigated in nine patients suffering from isolated (six patients) or prominent (three patients) essential tremor of the head. In a double-blind, placebo-controlled study the tremorolytic efficacy of propranolol has been assessed by a quantitative accelerometric method after a single oral dose (120 mg) and following 2 weeks of sustained treatment with two different dosage regimens of the drug (120 and 240 mg daily). As compared with placebo, a significant reduction in tremor magnitude was found following a single oral dose but not on sustained administration of the beta-blocker at either dosage. The results suggest that the efficacy of sustained propranolol on isolated or prominent essential head tremor is less predictable and satisfactory than expected on the basis of the single-dose response, as compared with hand tremor.

  13. Adrenergic beta 2-selective blocker in isoprenaline-enhanced essential tremor.

    Science.gov (United States)

    Teräväinen, H; Huttunen, J

    1987-01-01

    A beta 2-selective adrenergic-receptor-blocking drug, ICI 118.551, 150 mg/day, prevented almost as effectively as the nonselective antagonist propranolol, 240 mg/day, the isoprenaline enhancement of essential tremor amplitude.

  14. A Cerebellar Tremor in a Patient with Human Immunodeficiency Virus-1 Associated with Progressive Multifocal Leukoencephalopathy

    Directory of Open Access Journals (Sweden)

    Hee-Jin Kim

    2009-10-01

    Full Text Available Progressive multifocal leukoencephalopathy (PML is a demyelinating disease of the central nervous system (CNS caused by JC virus infection in oligodendrocytes, especially in patients with acquired immunodeficiency syndrome (AIDS. Movement disorders associated with PML are very rare. Here, we report a case of PML in an AIDS patient who presented with a cerebellar tremor, caused by lesions in the cerebellar outflow tract. A cerebellar tremor can be a rare clinical manifestation in patients with PML.

  15. A Cerebellar Tremor in a Patient with Human Immunodeficiency Virus-1 Associated with Progressive Multifocal Leukoencephalopathy

    Science.gov (United States)

    Kim, Hee-Jin; Lee, Jae-Jung; Lee, Phil Hyu

    2009-01-01

    Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by JC virus infection in oligodendrocytes, especially in patients with acquired immunodeficiency syndrome (AIDS). Movement disorders associated with PML are very rare. Here, we report a case of PML in an AIDS patient who presented with a cerebellar tremor, caused by lesions in the cerebellar outflow tract. A cerebellar tremor can be a rare clinical manifestation in patients with PML. PMID:24868366

  16. Validation of a new tool for automatic assessment of tremor frequency from video recordings

    Czech Academy of Sciences Publication Activity Database

    Uhríková, Z.; Šprdlík, Otakar; Hoskovcová, M.; Komárek, A.; Ulmanová, O.; Hlaváč, V.; Nugent, Ch. D.; Růžička, E.

    2011-01-01

    Roč. 198, č. 1 (2011), s. 110-113 ISSN 0165-0270 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : Tremor frequency * essential tremor * video analysis * Fourier transformation * accelerometry Subject RIV: BC - Control Systems Theory Impact factor: 1.980, year: 2011 http://library.utia.cas.cz/separaty/2011/TR/sprdlik-0359324.pdf

  17. 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.

  18. Tremor analysis by decomposition of acceleration into gravity and inertial acceleration using inertial measurement unit

    Czech Academy of Sciences Publication Activity Database

    Šprdlík, Otakar; Hurák, Z.; Hoskovcová, M.; Ulmanová, O.; Růžička, E.

    2011-01-01

    Roč. 6, č. 3 (2011), s. 269-289 ISSN 1746-8094 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : Tremor * Accelerometer * Inertial measurementunit * Gravitational artifact * Regression * Tremor ratingscale Subject RIV: BC - Control Systems Theory Impact factor: 1.000, year: 2011 http://library.utia.cas.cz/separaty/2011/TR/sprdlik-0350248.pdf

  19. Vertical components of surface vibrations induced by mining tremors in the Upper Silesian Coalfield, Poland

    International Nuclear Information System (INIS)

    Maciag, E.; Kowalski, W.

    1997-01-01

    Characteristics of vertical components of surface vibration is epicentral zones due to mining tremors in the Upper Silesian Coalfield (USC) are analysed. Both maximum acceleration amplitudes and dominant frequencies of vertical (Z) and horizontal (N-S and E-W) components of vibrations are compared. The role played by the vertical components of vibrations in estimates of hazard for surface structures excited by mining tremors is discussed. 8 refs., 7 figs

  20. Ambient seismic noise interferometry in Hawai'i reveals long-range observability of volcanic tremor

    Science.gov (United States)

    Ballmer, Silke; Wolfe, Cecily; Okubo, Paul G.; Haney, Matt; Thurber, Clifford H.

    2013-01-01

    The use of seismic noise interferometry to retrieve Green's functions and the analysis of volcanic tremor are both useful in studying volcano dynamics. Whereas seismic noise interferometry allows long-range extraction of interpretable signals from a relatively weak noise wavefield, the characterization of volcanic tremor often requires a dense seismic array close to the source. We here show that standard processing of seismic noise interferometry yields volcanic tremor signals observable over large distances exceeding 50 km. Our study comprises 2.5 yr of data from the U.S. Geological Survey Hawaiian Volcano Observatory short period seismic network. Examining more than 700 station pairs, we find anomalous and temporally coherent signals that obscure the Green's functions. The time windows and frequency bands of these anomalous signals correspond well with the characteristics of previously studied volcanic tremor sources at Pu'u 'Ō'ō and Halema'uma'u craters. We use the derived noise cross-correlation functions to perform a grid-search for source location, confirming that these signals are surface waves originating from the known tremor sources. A grid-search with only distant stations verifies that useful tremor signals can indeed be recovered far from the source. Our results suggest that the specific data processing in seismic noise interferometry—typically used for Green's function retrieval—can aid in the study of both the wavefield and source location of volcanic tremor over large distances. In view of using the derived Green's functions to image heterogeneity and study temporal velocity changes at volcanic regions, however, our results illustrate how care should be taken when contamination by tremor may be present.

  1. Development of a system for measurement and analysis of tremor using a three-axis accelerometer.

    Science.gov (United States)

    Mamorita, N; Iizuka, T; Takeuchi, A; Shirataka, M; Ikeda, N

    2009-01-01

    The aim of the study was to develop a low-cost and compact system for analysis of tremor using a three-axis accelerometer (the Wii Remote (Nintendo)). To analyze tremor, we hypothesized that the influence of gravitational acceleration should be separated from that of movement. This hypothesis was tested experimentally and we also attempted to record and analyze tremor using our system in a clinical ward. A system for tremor measurement and analysis was developed using the three-axis accelerometer built into the Wii Remote. The frequency and amplitude of mechanical oscillation were calculated using methods for frequency analysis of the axis of largest variance and an estimation of tremor amplitude. The system consists of a program for measurement and analysis of Wii Remote acceleration (Tremor Analyzer), a Wii Remote, a Bluetooth USB adapter and a Web camera. The Tremor Analyzer has a GUI (graphical user interface) that is divided into five seg- ments. The sampling period of the analyzer is 30 msec. To confirm the hypothesis, mechanical oscillations were fed to the Wii Remote. The peak frequency of the power spectrum and the frequency of the oscillation generator were in good agreement, except at 1 Hz (0.01 G) and 2 Hz (0.02 G). With a change in the sum of squares of the three axes from 1.0 to 1.8 (G), the estimated and generated amplitude (0.3 cm) were in close agreement. This system using a Wii Remote is capable of analyzing frequency and estimated amplitude of tremor between 3 Hz and 15 Hz.

  2. Deep Brain Stimulation Salvages a Flourishing Dental Practice: A Dentist with Essential Tremor Recounts his Experience

    OpenAIRE

    Giacopuzzi, Guy; Lising, Melanie; Halpern, Casey H

    2016-01-01

    In recounting his experience with deep brain stimulation (DBS), a practicing dentist challenged with long-standing bilateral essential tremor of the hands?shares insights into his diagnosis, treatments, and ultimately successful DBS surgery at Stanford University Medical Center, CA, USA. Now nearly one year after his surgery, his practice continues to flourish and he encourages others in his profession to consider the possibility of DBS as a definitive?treatment for tremors of the hand, which...

  3. Validation of a telephone screening tool for spasmodic dysphonia and vocal fold tremor.

    Science.gov (United States)

    Johnson, David M; Hapner, Edie R; Klein, Adam M; Pethan, Madeleine; Johns, Michael M

    2014-11-01

    The objective of this study was to ascertain whether clinicians can reliably distinguish between spasmodic dysphonia (SD)/vocal tremor and other voice disorders by telephone, despite this modality's limited frequency response. Randomized, single-blinded, and prospective study. Voice-disordered patients with (n = 22) and without (n = 17) SD and/or vocal tremor recorded standardized utterances via landline telephone. A laryngologist and two speech-language pathologists blinded to the diagnoses rated each recording as "yes" or "no" to "SD or tremor present?," and if "yes" categorized into adductor, abductor, tremor only, or adductor with tremor subtypes. Twenty-one recordings were presented twice at random so intrarater reliability could be assessed. All ratings were compared with gold standard diagnosis by a second laryngologist who performed a full examination, including videostroboscopy, on each patient. For the comparison "SD or tremor" yes versus no, sensitivity, specificity, positive predictive value, and negative predictive value are 90%, 95%, 96%, and 89%, respectively. Interrater reliability (Cohen kappa) compared with the gold standard ranged from 0.70 to 0.93 (substantial to almost perfect agreement). Cronbach alpha among three raters was 0.90 for this comparison. Intrarater reliability (number matched/number inspected) was very high, ranging from 0.97 to 1.0. Comparing gold standard and telephone rating of SD/tremor subtypes, kappa ranged from 0.48 to 0.60 (moderate agreement). Cronbach alpha among three raters was 0.88 for this comparison. Intrarater reliability ranged from 0.84 to 0.97. SD and tremor can be reliably distinguished from other voice disorders over the telephone. Copyright © 2014 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  4. Long-Term Efficacy of Constant Current Deep Brain Stimulation in Essential Tremor.

    Science.gov (United States)

    Rezaei Haddad, Ali; Samuel, Michael; Hulse, Natasha; Lin, Hsin-Ying; Ashkan, Keyoumars

    2017-07-01

    Ventralis intermedius deep brain stimulation is an established intervention for medication-refractory essential tremor. Newer constant current stimulation technology offers theoretical advantage over the traditional constant voltage systems in terms of delivering a more biologically stable therapy. There are no previous reports on the outcomes of constant current deep brain stimulation in the treatment of essential tremor. This study aimed to evaluate the long-term efficacy of ventralis intermedius constant current deep brain stimulation in patients diagnosed with essential tremor. Essential tremor patients implanted with constant current deep brain stimulation for a minimum of three years were evaluated. Clinical outcomes were assessed using the Fahn-Tolosa-Marin tremor rating scale at baseline and postoperatively at the time of evaluation. The quality of life in the patients was assessed using the Quality of Life in Essential Tremor questionnaire. Ten patients were evaluated with a median age at evaluation of 74 years (range 66-79) and a mean follow up time of 49.7 (range 36-78) months since starting stimulation. Constant current ventralis intermedius deep brain stimulation was well tolerated and effective in all patients with a mean score improvement from 50.7 ± 5.9 to 17.4 ± 5.7 (p = 0.0020) in the total Fahn-Tolosa-Marin rating scale score (65.6%). Furthermore, the total combined mean Quality of Life in Essential Tremor score was improved from 56.2 ± 4.9 to 16.8 ± 3.5 (p value = 0.0059) (70.1%). This report shows that long-term constant current ventralis intermedius deep brain stimulation is a safe and effective intervention for essential tremor patients. © 2017 International Neuromodulation Society.

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

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    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.

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

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    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.

  7. 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.

  8. Successful Treatment of Rubral Tremor by High-Dose Trihexyphenidyl: A Case Report

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    Li-Min Liou

    2006-03-01

    Full Text Available A 24-year-old male suffered from acute-onset right-sided hemiparesis, dysarthria, and ophthalmoplegia in February 2001. Brain magnetic resonance imaging revealed a cavernous angioma with hemorrhage over the left thalamus. Moreover, some rhythmic, coarse, low-frequency (2-3 Hz oscillation over the right wrist and elbow was noted 1 month later. Action tremor was more predominant than resting tremor. Rubral tremor was diagnosed on the basis of the clinical presentation and tremography analysis. Rubral tremor is not unusual, and pharmacotherapy is nearly always ineffective in clinical practice. Deep brain stimulation, thalamotomy, and pallidotomy are all considered effective according to recent research. However, they are either very expensive or invasive, and involve surgical risks. In our patient, we tried valproate, clonazepam, and verapamil one after another, but all in vain. Finally, titration of trihexyphenidyl provided significant benefit. The tremor was successfully controlled by a single high daily dose of trihexyphenidyl (38 mg without severe or uncomfortable side effects. Here, we report a case of successful monotherapy of rubral tremor with high-dose trihexyphenidyl.

  9. Simulations of tremor-related creep reveal a weak crustal root of the San Andreas Fault

    Science.gov (United States)

    Shelly, David R.; Bradley, Andrew M.; Johnson, Kaj M.

    2013-01-01

    Deep aseismic roots of faults play a critical role in transferring tectonic loads to shallower, brittle crustal faults that rupture in large earthquakes. Yet, until the recent discovery of deep tremor and creep, direct inference of the physical properties of lower-crustal fault roots has remained elusive. Observations of tremor near Parkfield, CA provide the first evidence for present-day localized slip on the deep extension of the San Andreas Fault and triggered transient creep events. We develop numerical simulations of fault slip to show that the spatiotemporal evolution of triggered tremor near Parkfield is consistent with triggered fault creep governed by laboratory-derived friction laws between depths of 20–35 km on the fault. Simulated creep and observed tremor northwest of Parkfield nearly ceased for 20–30 days in response to small coseismic stress changes of order 104 Pa from the 2003 M6.5 San Simeon Earthquake. Simulated afterslip and observed tremor following the 2004 M6.0 Parkfield earthquake show a coseismically induced pulse of rapid creep and tremor lasting for 1 day followed by a longer 30 day period of sustained accelerated rates due to propagation of shallow afterslip into the lower crust. These creep responses require very low effective normal stress of ~1 MPa on the deep San Andreas Fault and near-neutral-stability frictional properties expected for gabbroic lower-crustal rock.

  10. Episodic tremor and slip explained by fluid-enhanced microfracturing and sealing

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    Bernaudin, M.; Gueydan, F.

    2017-12-01

    A combination of non-volcanic tremor and transient slow slip events behaviors is commonly observed at plate interface, between locked/seismogenic zone at low depths and stable/ductile creep zone at larger depths. This association defines Episodic Tremor and Slip, systematically highlighted by over-pressurized fluids and near failure shear stress conditions. Here we propose a new mechanical approach that provides for the first time a mechanical and field-based explanation of the observed association between non-volcanic tremor and slow slip events. In contrast with more classical rate-and-state models, this physical model uses a ductile rheology with grain size sensitivity, fluid-driven microfracturing and sealing (e.g. grain size reduction and grain growth) and related pore fluid pressure fluctuations. We reproduce slow slip events by transient ductile strain localization as a result of fluid-enhanced microfracturing and sealing. Moreover, occurrence of macrofracturing during transient strain localization and local increase in pore fluid pressure well simulate non-volcanic tremor. Our model provides therefore a field-based explanation of episodic tremor and slip and moreover predicts the depth and temperature ranges of their occurrence in subduction zones. It implies furthermore that non-volcanic tremor and slow slip events are physically related.

  11. Gabapentin can improve postural stability and quality of life in primary orthostatic tremor.

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

    2005-07-01

    Primary orthostatic tremor (OT) is characterized by leg tremor and instability on standing. High frequency (13-18 Hz) tremor bursting is present in leg muscles during stance, and posturography has shown greater than normal sway. We report on an open-label add-on study of gabapentin in 6 patients with OT. Six patients were studied with surface electromyography, force platform posturography, and a modified Parkinson's disease questionnaire (PDQ-39) quality of life (QOL) scale before and during treatment with gabapentin 300 mg t.d.s. If on other medications for OT, these were continued unchanged. Of the 6 patients, 4 reported a subjective benefit of 50 to 75% with gabapentin, 3 of whom showed reduced tremor amplitude and postural sway of up to 70%. Dynamic balance improved in all 3 patients who completed the protocol. QOL data from 5 patients showed improvement in all cases. No adverse effects were noted. Gabapentin may improve tremor, stability, and QOL in patients with OT, and symptomatic response correlated with a reduction in tremor amplitude and postural sway. The findings confirm previous reports of symptomatic benefit with gabapentin and provide justification for larger controlled clinical trials. Further work is required to establish the optimal dosage and to validate the methods used to quantify the response to treatment. Copyright 2005 Movement Disorder Society.

  12. Forecast for Artificial Muscle Tremor Behavior Based on Dynamic Additional Grey Catastrophe Prediction

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    Yu Fu

    2018-02-01

    Full Text Available Recently, bio-inspired artificial muscles based on ionic polymers have shown a bright perspective in engineering and medical research, but the inherent tremor behavior can cause instability of output response. In this paper, dynamic additional grey catastrophe prediction (DAGCP is proposed to forecast the occurrence time of tremor behavior, providing adequate preparation time for the suppression of the chitosan-based artificial muscles. DAGCP constructs various dimensions of time subsequence models under different starting points based on the threshold of tremor occurrence times and peak-to-peak values in unit time. Next, the appropriate subsequence is selected according to grey correlation degree and prediction accuracy, then it is updated with the newly generated values to achieve a real-time forecast of forthcoming tremor time. Compared with conventional grey catastrophe prediction (GCP, the proposed method has the following advantages: (1 the degradation of prediction accuracy caused by the immobilization of original parameters is prevented; (2 the dynamic input, real-time update and gradual forecast of time sequence are incorporated into the model. The experiment results show that the novel DAGCP can predict forthcoming tremor time earlier and more accurately than the conventional GCP. The generation mechanism of tremor behavior is illustrated as well.

  13. Detecting Micro-seismicity and Long-duration Tremor-like Events from the Oklahoma Wavefield Experiment

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    Li, C.; Li, Z.; Peng, Z.; Zhang, C.; Nakata, N.

    2017-12-01

    Oklahoma has experienced abrupt increase of induced seismicity in the last decade. An important way to fully understand seismic activities in Oklahoma is to obtain more complete earthquake catalogs and detect different types of seismic events. The IRIS Community Wavefield Demonstration Experiment was deployed near Enid, Oklahoma in Summer of 2016. The dataset from this ultra-dense array provides an excellent opportunity for detecting microseismicity in that region with wavefield approaches. Here we examine continuous waveforms recorded by 3 seismic lines using local coherence for ultra-dense arrays (Li et al., 2017), which is a measure of cross-correlation of waveform at each station with its nearby stations. So far we have detected more than 5,000 events from 06/22/2016 to 07/20/2016, and majority of them are not listed on the regional catalog of Oklahoma or global catalogs, indicating that they are local events. We also identify 15-20 long-period long-duration events, some of them lasting for more than 500 s. Such events have been found at major plate-boundary faults (also known as deep tectonic tremor), as well as during hydraulic fracturing, slow-moving landslides and glaciers. Our next step is to locate these possible tremor-like events with their relative arrival times across the array and compare their occurrence times with solid-earth tides and injection histories to better understand their driving mechanisms.

  14. A zero phase adaptive fuzzy Kalman filter for physiological tremor suppression in robotically assisted minimally invasive surgery.

    Science.gov (United States)

    Sang, Hongqiang; Yang, Chenghao; Liu, Fen; Yun, Jintian; Jin, Guoguang; Chen, Fa

    2016-12-01

    Hand physiological tremor of surgeons can cause vibration at the surgical instrument tip, which may make it difficult for the surgeon to perform fine manipulations of tissue, needles, and sutures. A zero phase adaptive fuzzy Kalman filter (ZPAFKF) is proposed to suppress hand tremor and vibration of a robotic surgical system. The involuntary motion can be reduced by adding a compensating signal that has the same magnitude and frequency but opposite phase with the tremor signal. Simulations and experiments using different filters were performed. Results show that the proposed filter can avoid the loss of useful motion information and time delay, and better suppress minor and varying tremor. The ZPAFKF can provide less error, preferred accuracy, better tremor estimation, and more desirable compensation performance, to suppress hand tremor and decrease vibration at the surgical instrument tip. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT: A clinical follow up study

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    Manuel eMenéndez-González

    2014-04-01

    Full Text Available The [123I]ioflupane - a dopamine transporter radioligand - SPECT (DaT-SPECT has proven to be useful in the differential diagnosis of tremor. Here, we investigate the diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT. Therefore, 30 patients with tremor and normal DaT-SPECT were followed up for 2 years. In 18 cases we were able to make a diagnosis. The residual 12 patients underwent a second DaT-SPECT, were then followed for additional 12 months and thereafter the diagnosis was reconsidered again. The final diagnoses included cases of essential tremor, dystonic tremor, multisystem atrophy, vascular parkinsonism, progressive supranuclear palsy, corticobasal degeneration, fragile X–associated tremor ataxia syndrome, psychogenic parkinsonism, iatrogenic parkinsonism and Parkinson’s disease. However, for 6 patients the diagnosis remained uncertain. Larger series are needed to better establish the relative frequency of the different conditions behind these cases.

  16. Diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT: a clinical follow up study.

    Science.gov (United States)

    Menéndez-González, Manuel; Tavares, Francisco; Zeidan, Nahla; Salas-Pacheco, José M; Arias-Carrión, Oscar

    2014-01-01

    The [(123)I]ioflupane-a dopamine transporter radioligand-SPECT (DaT-SPECT) has proven to be useful in the differential diagnosis of tremor. Here, we investigate the diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT. Therefore, 30 patients with tremor and normal DaT-SPECT were followed up for 2 years. In 18 cases we were able to make a diagnosis. The residual 12 patients underwent a second DaT-SPECT, were then followed for additional 12 months and thereafter the diagnosis was reconsidered again. The final diagnoses included cases of essential tremor, dystonic tremor, multisystem atrophy, vascular parkinsonism, progressive supranuclear palsy, corticobasal degeneration, fragile X-associated tremor ataxia syndrome, psychogenic parkinsonism, iatrogenic parkinsonism and Parkinson's disease. However, for 6 patients the diagnosis remained uncertain. Larger series are needed to better establish the relative frequency of the different conditions behind these cases.

  17. A 15 year catalog of more than 1 million low-frequency earthquakes: Tracking tremor and slip along the deep San Andreas Fault

    Science.gov (United States)

    Shelly, David R.

    2017-05-01

    Low-frequency earthquakes (LFEs) are small, rapidly recurring slip events that occur on the deep extensions of some major faults. Their collective activation is often observed as a semicontinuous signal known as tectonic (or nonvolcanic) tremor. This manuscript presents a catalog of more than 1 million LFEs detected along the central San Andreas Fault from 2001 to 2016. These events have been detected via a multichannel matched-filter search, cross-correlating waveform templates representing 88 different LFE families with continuous seismic data. Together, these source locations span nearly 150 km along the central San Andreas Fault, ranging in depth from 16 to 30 km. This accumulating catalog has been the source for numerous studies examining the behavior of these LFE sources and the inferred slip behavior of the deep fault. The relatively high temporal and spatial resolutions of the catalog have provided new insights into properties such as tremor migration, recurrence, and triggering by static and dynamic stress perturbations. Collectively, these characteristics are inferred to reflect a very weak fault likely under near-lithostatic fluid pressure, yet the physical processes controlling the stuttering rupture observed as tremor and LFE signals remain poorly understood. This paper aims to document the LFE catalog assembly process and associated caveats, while also updating earlier observations and inferred physical constraints. The catalog itself accompanies this manuscript as part of the electronic supplement, with the goal of providing a useful resource for continued future investigations.

  18. A sensitive, handheld vapor sensor based on microcantilevers

    Science.gov (United States)

    Pinnaduwage, L. A.; Hedden, D. L.; Gehl, A.; Boiadjiev, V. I.; Hawk, J. E.; Farahi, R. H.; Thundat, T.; Houser, E. J.; Stepnowski, S.; McGill, R. A.; Deel, L.; Lareau, R. T.

    2004-11-01

    We report the development of a handheld sensor based on piezoresistive microcantilevers that does not depend on optical detection, yet has high detection sensitivity. The sensor is able to detect vapors from the plastic explosives pentaerythritol tetranitrate and hexahydro-1,3,5-triazine at levels below 10 parts per trillion within few seconds of exposure under ambient conditions. A differential measurement technique has yielded a rugged sensor that is unaffected by vibration and is able to function as a "sniffer." The microelectromechanical system sensor design allows for the incorporation of hundreds of microcantilevers with suitable coatings in order to achieve sufficient selectivity in the future, and thus could provide an inexpensive, unique platform for the detection of chemical, biological, and explosive materials.

  19. Hand-held spectrophotometer design for textile fabrics

    Science.gov (United States)

    Böcekçi, Veysel Gökhan; Yıldız, Kazım

    2017-09-01

    In this study, a hand-held spectrophotometer was designed by taking advantage of the developments in modern optoelectronic technology. Spectrophotometer devices are used to determine the color information from the optic properties of the materials. As an alternative to a desktop spectrophotometer device we have implemented, it is the first prototype, low cost and portable. The prototype model designed for the textile industry can detect the color tone of any fabric. The prototype model consists of optic sensor, processor, display floors. According to the color applied on the optic sensor, it produces special frequency information on its output at that color value. In Arduino type processor, the frequency information is evaluated by the program we have written and the color tone information between 0-255 ton is decided and displayed on the screen.

  20. Comparative Geometrical Investigations of Hand-Held Scanning Systems

    Science.gov (United States)

    Kersten, T. P.; Przybilla, H.-J.; Lindstaedt, M.; Tschirschwitz, F.; Misgaiski-Hass, M.

    2016-06-01

    An increasing number of hand-held scanning systems by different manufacturers are becoming available on the market. However, their geometrical performance is little-known to many users. Therefore the Laboratory for Photogrammetry & Laser Scanning of the HafenCity University Hamburg has carried out geometrical accuracy tests with the following systems in co-operation with the Bochum University of Applied Sciences (Laboratory for Photogrammetry) as well as the Humboldt University in Berlin (Institute for Computer Science): DOTProduct DPI-7, Artec Spider, Mantis Vision F5 SR, Kinect v1 + v2, Structure Sensor and Google's Project Tango. In the framework of these comparative investigations geometrically stable reference bodies were used. The appropriate reference data were acquired by measurement with two structured light projection systems (AICON smartSCAN and GOM ATOS I 2M). The comprehensive test results of the different test scenarios are presented and critically discussed in this contribution.