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1
Keogh, Justin W. L., et n/a. « Constraints on the Control of Physiological Tremor ». Griffith University. School of Physiotherapy and Exercise Science, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070208.110453.
Texte intégralRésumé :
This thesis sought to: 1) examine the effect of a number of organism and task constraints on the control of two forms of physiological tremor, namely postural and finger-pinch force tremor; and 2) determine if the expected constraint-related changes in tremor output were associated with alterations in the control strategy utilised by the performer. The organism constraints were age and resistance-training (for both forms of tremor), while the task constraints were visual feedback, target size and limb preference (postural tremor) and mean force, target shape and limb preference (force tremor). The postural (index finger) tremor amplitude of young adults was significantly greater in the augmented vision (AV) than normal vision (NV) conditions and when using the non-preferred than preferred limb. Even greater differences/changes in postural tremor amplitude were observed as a function of aging and training. Older adults had significantly more index finger tremor amplitude than young adults. Regardless, the older adults who completed a six weeks program of unilateral strength- or coordination-training were able to significantly reduce their tremor amplitude. Although the training-related reductions in tremor amplitude were of a greater magnitude for the trained than untrained limb, a significant reduction in the tremor amplitude of the untrained limb was also observed for the coordination-training group. All of these significant differences/changes in tremor amplitude were associated with significant changes in a number of other dependent variables. For example, the task- and age-related increases in tremor amplitude were primarily a result of greater 8-12 Hz tremor power and were associated with increased EMG activity/co-activation of the extensor digitorum (ED) and flexor digitorum superficialis (FDS) muscles and a significant reduction in intra-limb (index finger-hand and forearm-upper arm) coupling. The significant reductions in tremor amplitude observed for the resistance-trained older adults was a result of a significant decline in 8-12 Hz power and were associated with a significant reduction in ED and FDS co-activation. However, no significant change in intra-limb coupling was observed. The overall trends observed in the results for the finger-pinch force tremor experiments were similar to those for postural tremor. Older adults had significantly more finger-pinch force tremor (i.e. force variability and targeting error) than young adults, although older adults who performed six weeks of unilateral strength-training were able to significantly reduce the force variability and targeting error of the trained limb. No significant training-related reduction in force tremor was however observed for the untrained limb. The significant age-related increase in force tremor was a result of greater low frequency (less than 2 Hz) power and was associated with a significant loss of inter-digit force sharing and coupling as well as tactile sensitivity. Interestingly, the training-related decreases in force tremor were not associated with significant changes in any of the frequency, sharing or coupling measures. Collectively, the results of the five experiments contained in this thesis add much to our understanding of postural and force tremor. Results indicated that numerous task and organism constraints can have a substantial effect on the resulting tremor output. Furthermore, the task- and age-related differences in the power spectral, muscle activity and coupling measures suggested that the changes in tremor output were the result of the use of an altered (sub-optimal) control strategy. The age-related increase in postural and force tremor amplitude may therefore reflect not only an overall decline in neuromuscular system function, but also the relative inability of older adults to effectively coordinate the output of numerous degrees of freedom (limb segments). The effect of the aging process on tremor output was somewhat reversible, with the older adults who performed resistance-training significantly improving their control of both postural and force tremor. There was some evidence that resistance-training could produce cross-education effects in older adults, although these were only statistically significant for postural tremor amplitude in the coordination-training group and for wrist flexion strength in the strength-training group. The relative brevity of the training program (6 weeks) and the observable cross-education effects suggest that the reduction in tremor amplitude and increases in strength were primarily a result of neural adaptations. Such findings further support the prescription of resistance-training for improving physical function in older individuals.
2
Keogh, Justin W. L. « Constraints on the Control of Physiological Tremor ». Thesis, Griffith University, 2006. http://hdl.handle.net/10072/366057.
Texte intégralRésumé :
This thesis sought to: 1) examine the effect of a number of organism and task constraints on the control of two forms of physiological tremor, namely postural and finger-pinch force tremor; and 2) determine if the expected constraint-related changes in tremor output were associated with alterations in the control strategy utilised by the performer. The organism constraints were age and resistance-training (for both forms of tremor), while the task constraints were visual feedback, target size and limb preference (postural tremor) and mean force, target shape and limb preference (force tremor). The postural (index finger) tremor amplitude of young adults was significantly greater in the augmented vision (AV) than normal vision (NV) conditions and when using the non-preferred than preferred limb. Even greater differences/changes in postural tremor amplitude were observed as a function of aging and training. Older adults had significantly more index finger tremor amplitude than young adults. Regardless, the older adults who completed a six weeks program of unilateral strength- or coordination-training were able to significantly reduce their tremor amplitude. Although the training-related reductions in tremor amplitude were of a greater magnitude for the trained than untrained limb, a significant reduction in the tremor amplitude of the untrained limb was also observed for the coordination-training group. All of these significant differences/changes in tremor amplitude were associated with significant changes in a number of other dependent variables. For example, the task- and age-related increases in tremor amplitude were primarily a result of greater 8-12 Hz tremor power and were associated with increased EMG activity/co-activation of the extensor digitorum (ED) and flexor digitorum superficialis (FDS) muscles and a significant reduction in intra-limb (index finger-hand and forearm-upper arm) coupling. The significant reductions in tremor amplitude observed for the resistance-trained older adults was a result of a significant decline in 8-12 Hz power and were associated with a significant reduction in ED and FDS co-activation. However, no significant change in intra-limb coupling was observed. The overall trends observed in the results for the finger-pinch force tremor experiments were similar to those for postural tremor. Older adults had significantly more finger-pinch force tremor (i.e. force variability and targeting error) than young adults, although older adults who performed six weeks of unilateral strength-training were able to significantly reduce the force variability and targeting error of the trained limb. No significant training-related reduction in force tremor was however observed for the untrained limb. The significant age-related increase in force tremor was a result of greater low frequency (less than 2 Hz) power and was associated with a significant loss of inter-digit force sharing and coupling as well as tactile sensitivity. Interestingly, the training-related decreases in force tremor were not associated with significant changes in any of the frequency, sharing or coupling measures. Collectively, the results of the five experiments contained in this thesis add much to our understanding of postural and force tremor. Results indicated that numerous task and organism constraints can have a substantial effect on the resulting tremor output. Furthermore, the task- and age-related differences in the power spectral, muscle activity and coupling measures suggested that the changes in tremor output were the result of the use of an altered (sub-optimal) control strategy. The age-related increase in postural and force tremor amplitude may therefore reflect not only an overall decline in neuromuscular system function, but also the relative inability of older adults to effectively coordinate the output of numerous degrees of freedom (limb segments). The effect of the aging process on tremor output was somewhat reversible, with the older adults who performed resistance-training significantly improving their control of both postural and force tremor. There was some evidence that resistance-training could produce cross-education effects in older adults, although these were only statistically significant for postural tremor amplitude in the coordination-training group and for wrist flexion strength in the strength-training group. The relative brevity of the training program (6 weeks) and the observable cross-education effects suggest that the reduction in tremor amplitude and increases in strength were primarily a result of neural adaptations. Such findings further support the prescription of resistance-training for improving physical function in older individuals.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Physiotherapy and Exercise Science
Full Text
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Miesner, Jochen. « Augenbewegungsstörungen bei essentiellem Tremor ». [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=974496103.
Texte intégral
4
Schuurman, Peter Richard. « Thalamic surgery for tremor ». [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/65876.
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5
Pinto, Manuel Duarte Carvalho Lages. « Tremor essencial : visão global da doença ». Master's thesis, Universidade da Beira Interior, 2013. http://hdl.handle.net/10400.6/1506.
Texte intégralRésumé :
O tremor essencial é uma das patologias mais comuns entre as patologias do sistema nervoso,
sendo que é vista frequentemente pelos médicos neurologistas. Estima-se que a prevalência a
nível mundial desta doença se situe entre os 0,41% e os 3,92%.
Apesar de não haver uma causa definida para a doença, o que faz com que a sua etiologia
ainda permaneça, em grande parte, desconhecida dados recentes indicam-nos que a patologia
ocorre com um padrão familiar, embora se tenha verificado que também pode ocorrer de
forma esporádica. Foram identificados até ao momento pelo menos 3 genes que podem
aumentar a suscetibilidade para o tremor essencial: ETM1, ETM2 e ETM3. Existem também
evidências que alguns fatores de risco podem contribuir para o surgimento da patologia, entre
eles o álcool, o chumbo e os alcaloides do grupo das β-carbolinas. A evidência atual indicanos
que o tremor essencial é uma doença neurodegenerativa, em que há envolvimento
seletivo, tanto anatomicamente como fisiologicamente, de um sistema organizado de
neurónios, mais especificamente as células de Purkinje; para além disso, a patologia pode
eventualmente afetar sistemas não- motores, como por exemplo, a cognição e o olfato.
O tremor essencial é definido classicamente por um tremor de ação (postural ou cinético),
bilateral, em grande parte simétrico, que afeta mais frequentemente os braços e a cabeça e
que é visível e persistente. O diagnóstico diferencial é feito principalmente com a doença de
Parkinson.
As possibilidades terapêuticas para o tratamento do tremor essencial usadas hoje em dia
foram descobertas por tentativa-erro, sendo estas originalmente concebidos para outras
patologias. Os dois únicos fármacos com eficácia estabelecida para a patologia são o
Propranolol e a Primidona, sendo que a cirurgia está recomendada para casos mais graves e
refratários. Em estudo continuam futuras possibilidades terapêuticas.Essential tremor is one of the most common diseases among the pathologies of the nervous system, which is seen frequently by neurologists. It is estimated that the worldwide prevalence of this disease is between 0.41% and 3.92%. Although there is no definite cause for the disease, which causes its etiology to remain still largely unknown, recent data indicates that the pathology occurs with a familiar pattern, although it has been found that it can also occur in a sporadic way. Until today three loci have been identified that may increase the susceptibility to essential tremor: ETM1, ETM2 and ETM3. There is also evidence that some risk factors may contribute to the arising of the disease, among them alcohol, lead and the alkaloids group of β-carbolines. Current evidence indicates that essential tremor is a neurodegenerative disorder in which there is selective involvement, both anatomically and physiologically, of an organized system of neurons, more specifically Purkinje cells; moreover the condition can eventually affect non-motor systems, for example, cognition and smell. Essential tremor is classically defined by an action tremor (postural or kinetic), bilaterally, mostly symmetrical, which affects more often arms and head and that is visible and persistent. The differential diagnosis is made primarily with Parkinson's disease. The therapeutic possibilities for the treatment of essential tremor used nowadays were discovered by trial-error, these being originally designed for other diseases. The only two drugs with established efficacy to the pathology are Propranolol and Primidone, with the surgery being recommended for more severe cases and refractories. Future therapeutic possibilities are now being studied.
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Markez, Sonja. « Development of a hand tremor quantification device for the measurement of pathological tremor ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/MQ53333.pdf.
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Corie, Thomas Henry. « Simulated Tremor Propagation in the Upper Limb : From Muscle Activity to Joint Displacement ». BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6777.
Texte intégralRésumé :
Although tremor is the most common movement disorder, there are few non-invasive treatment options. One of the obstacles to creating effective tremor suppression devices is our lack of understanding regarding where tremor originates (which muscles), how it propagates through the limb (to which degrees of freedom, DOF), and where it manifests most severely (which DOF). To investigate these questions, we created a simple, linear time-invariant model to simulate tremor, with tremorogenic muscle activity input (in the 15 major superficial muscles from the shoulder to the wrist) and joint displacement output (in the 7 major upper limb DOF). The model included excitation-contraction dynamics, musculoskeletal geometry (muscle moment arms) and the mechanical impedance (inertia, damping, and stiffness) of the limb. From our simulation results, we determined four principles of tremor propagation. First, the distribution of tremor depends strongly on musculoskeletal dynamics. Second, the spreading of tremor is due to inertial coupling (primarily) and musculoskeletal geometry (secondarily). Third, tremor spreads narrowly in the sense that most of the tremor caused by a muscle occurs in a small number of DOF. Lastly, assuming uniform distribution of tremorogenic activity among upper-limb muscles, tremor increases proximal-distally, and the contribution from muscles increases proximal-distally.
8
Veluvolu, Kalyana [Verfasser]. « Real-time Filtering of Physiological Tremor for Microsurgery. Physiological Tremor Robotic Compensation / Kalyana Veluvolu ». München : GRIN Verlag, 2020. http://d-nb.info/1220832847/34.
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Geiger, Daniel William. « Characterization of Postural Tremor in Essential Tremor Using a Seven-Degree-of-Freedom Model ». BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5684.
Texte intégralRésumé :
Essential Tremor (ET), a condition characterized by postural and kinetic tremor in the upper limbs, is one of the most prevalent movement disorders. While pharmaceutical and surgical treatment options exist, they are not ideal. Assistive devices have the potential to provide relief to patients but are largely unexplored for ET. Furthermore, prior characterizations of essential tremor have focused on endpoint tremor and provide insufficient detail for designing such a device. We propose and demonstrate a novel method for characterizing essential tremor in the 7 proximal degrees of freedom (DOF) of the upper limb in various postures. In addition, we provide a preliminary characterization in a small number of patients with mild ET. We collected data from 10 patients with ET. Subjects were instrumented with four electromagnetic sensors that recorded orientation of upper limb segments. After a calibration, each subject positioned his/her upper limb in 16 different postures for 15 seconds each. This procedure was repeated 4 times for each subject, with each repetition being considered a run. Sensor data were converted to angular kinematic data for each DOF using inverse kinematics, a practice unique to this study. These data were then analyzed in the frequency domain to calculate the power associated with the tremor in each DOF and posture. More specifically, we computed the area of the periodogram over the 4-12 Hz frequency band typically associated with ET [narrow-band area (NBA)] and over the wider frequency band from 2 Hz to the Nyquist frequency [wide-band area (WBA)]. If significant peaks were found in the 4-12 Hz band, their frequency and amplitude were reported. Mixed-model ANOVA tests were used to investigate effects of DOF, posture, run, gravity, and patient characteristics on reported measures. NBA and WBA varied significantly between DOF, being lowest in the wrist, intermediate in the shoulder, and greatest in the elbow and forearm (pronation-supination). NBA and WBA also varied significantly with posture. Only 5% of observations had significant peaks, with 49% of peaks occurring in wrist flexion-extension and 39% occurring in wrist radial-ulnar deviation. Peak frequency was quite stereotyped (5.7 Hz ± 1.3Hz). Run had no significant effects, indicating that tremor measures were consistent over the duration of the experiment. Effects of gravity and demographic factors on measures were mixed and did not present a discernible pattern. This preliminary characterization suggests that tremor may be focused in a subset of upper limb DOF, being greatest (in terms of power) in elbow flexion-extension and forearm pronation-supination, and most concentrated (with peaks at a stereotyped frequency) in wrist flexion-extension and radial-ulnar deviation. Our method of 7 DOF characterization through inverse kinematics, in conjunction with future research (isolation studies, EMG, and finger DOF) may allow for optimal tremor suppression by an orthosis.
10
Hemmerich, Abby Leigh. « The distribution and severity of tremor in speech structures of persons with vocal tremor ». Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/2891.
Texte intégralRésumé :
Background: Vocal tremor affects over half a million Americans. Tremor can affect structures within the respiratory, laryngeal, velopharyngeal, or oral regions (Critchley, 1949). No study has related the of tremor severity in structures in all four of these regions to the severity of vocal tremor. Purpose: The purpose of this study was (a) to describe the distribution and severity of tremor throughout the vocal tract and (b) to relate that to the severity of the voice tremor. We hypothesized that tremor would be widespread throughout the vocal tract, but most prevalent in the larynx, specifically in the true vocal folds. Additionally, we expected vocal tremor severity to be directly related to the distribution and severity of tremor in structures of the vocal tract. Method: Twenty adults with vocal tremor and two age-matched controls participated in the study. Two judges, experienced in assessment of laryngeal movement disorders, rated the tremor severity in each of 15 structures during sustained /i/, /s/, /h/, and rest breathing, and the severity of the voice tremor during sustained /i/, /s/, and /h/. Results: A novel finding of this study was the identification of distribution and severity of tremor in vocal tract structures associated with mild, moderate, and severe vocal tremor. Participants with mild voice tremor tended to show tremor limited to structures of the larynx, and in some cases, the velopharynx, and on average, had three structures affected (most commonly true vocal folds, supraglottic structures, and hypopharynx). Participants with moderate voice tremor tended to show tremor in the larynx and velopharynx, and on average, had five structures affected (most commonly true vocal folds, supraglottic structures, hypopharynx, vertical laryngeal movement, and some other velar, oral, or respiratory structure). Those with severe voice tremor showed tremor in the larynx, velopharynx, and beyond and on average, had eight structures affected (most commonly true vocal folds, supraglottic structures, hypopharynx, vertical laryngeal movement, anterior and lateral chest movement, velum, and jaw). A second novel finding, obtained through regression analyses, was that tremor severity of the supraglottic structures and vertical laryngeal movement contributed the most to the voice tremor severity during sustained phonation (r=0.77, F=16.17, p<0.0001). A strong positive correlation (r=0.72) was found between the Tremor Index, a composite value of the distribution and severity of structural tremor, and the severity of the voice tremor during sustained phonation. The correlation between the severity of tremor in the true vocal folds and the voice tremor was moderate (r=0.46). Mean voice tremor severity was greater in participants over age 75 (mean=2.25) than those between 66 and 75 years (mean=1.5) and under age 65 (mean=1.8). Mean Tremor Index, was greater in participants over age 65 (mean TI=68) than those under age 65 (mean=41). In this group of 20 participants, laryngeal/hypopharyngeal structures were most frequently (95%) and severely (rated 1.7 out of 3) affected, followed by velopharyngeal (40% occurrence, 1.3 severity), respiratory (40% occurrence, 1.1 severity), and oral (40% occurrence, 1.0 severity) regions during sustained phonation. Tremor was also identified more often and with greater severity in the larynx for sustained /s/ (70% occurrence, 1.7 severity), /h/ (40% occurrence, 1.7 severity), and rest breathing (45% occurrence, 1.6 severity) than other regions. During the voiceless and rest breathing tasks, the greatest tremor severity was noted in the true vocal folds. Conclusion: Evaluation of the distribution and severity of tremor may be useful in guiding behavioral and medical treatment of voice tremor and for providing prognostic information regarding response to laryngeal botulinum toxin injection.
11
Bejugam, Santosh. « Tremor quantification and parameter extraction ». Thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-16021.
Texte intégralRésumé :
Tremor is a neuro degenerative disease causing involuntary musclemovements in human limbs. There are many types of tremor that arecaused due to the damage of nerve cells that surrounds thalamus of thefront brain chamber. It is hard to distinguish or classify the tremors asthere are many reasons behind the formation of specific category, soevery tremor type is named behind its frequency type. Propermedication for the cure by physician is possible only when the disease isidentified.Because of the argument given in the above paragraph, there is a needof a device or a technique to analyze the tremor and for extracting theparameters associated with the signal. These extracted parameters canbe used to classify the tremor for onward identification of the disease.There are various diagnostic and treatment monitoring equipment areavailable for many neuromuscular diseases. This thesis is concernedwith the tremor analysis for the purpose of recognizing certain otherneurological disorders. A recording and analysis system for human’stremor is developed.The analysis was performed based on frequency and amplitudeparameters of the tremor. The Fast Fourier Transform (FFT) and higherorderspectra were used to extract frequency parameters (e.g., peakamplitude, fundamental frequency of tremor, etc). In order to diagnosesubjects’ condition, classification was implemented by statisticalsignificant tests (t‐test).
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Manohar, Jayashankar. « Detecting Parkinson Tremor Using Bluetooth ». Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208250.
Texte intégralRésumé :
Wearable technology is used today for many different applications such as heart rate monitoring and other clinical applications. This thesis aims at developing a Parkinson tremor monitoring application and contributes to optimizing the power consumptionof the system. The monitoring application is developed by implementing software on an embedded hardware prototype to collect accelerometer sensor data to store it in an SD card and to transfer the sensor data via Bluetooth to PC or mobile devices. Since the wearable device has to consume limited energy supplied by the battery, this project also includes reducing the energy consumption of the system by duty cycling the hardware peripherals of the system.
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Williams, Elizabeth R. « Network contributors to physiological tremor ». Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500953.
Texte intégralRésumé :
This thesis investigates circuits within the brain and spinal cord that contribute to -10 Hz physiological tremor and slow finger movement discontinuities. Electrophysiological recordings were made from the motor areas of two macaque monkeys trained to perform index finger flexion movements whilst tracking a moving target. We recorded local field potentials and single units from the primary motor cortex (Ml), deep cerebellar nuclei (DCN), pontomedullary reticular formation (PMRF) and the intermediate zone of the spinal cord (SC). Activity for all areas was coherent with finger acceleration at -10 Hz.
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Stichter, Cavener Beth. « Tremble, shiver ». The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1273838868.
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Stichter, Beth Cavener. « Tremble, shiver ». The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1285254868.
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Meixner, Linda. « Retrospektive Analyse der olfaktorischen Testung in Bezug auf die Differentialdiagnosen von Parkinsonsyndromen und Tremorerkrankungen ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-203747.
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Wills, A. J. « Positron emission tomography studies of tremor ». Thesis, Queen Mary, University of London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297290.
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Ahlf, Anjuli [Verfasser]. « Klinische Parameter des essenziellen Tremors / Anjuli Ahlf ». Kiel : Universitätsbibliothek Kiel, 2017. http://d-nb.info/1133074022/34.
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Standring, David Jordan. « Distribution of Tremorogenic Activity among the MajorSuperficial Muscles of the Upper Limb inSubjects with Essential Tremor ». BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7557.
Texte intégralRésumé :
Optimized peripheral tremor suppression could address many limitations of surgical or medicinal treatments of Essential Tremor, however it is not well understood how the tremorogenic activity is distributed among the muscles of the upper limb, and therefore how to optimize such suppression. We recorded electromyographic (EMG) activity in the 15 major superficial muscles from the shoulder to the wrist while subjects performed postural and kinetic tasks similar to activities of daily living. We calculated the power spectral density and computed the total power in the tremor band (4"12 Hz) for each muscle, from which we determined the distribution of tremorogenic activity among the 15 muscles for various conditions. Differences in distribution between conditions were quantified as Pearson correlation coefficients. All 15 muscles exhibited some tremorogenic activity. The anterior deltoid exhibited by far the most power, the wrist extensors had more power than other distal muscles, and the triceps longus showed the least power. Distributions among muscles was highly consistent across repetitions (r = 0.91 ± 0.07) and somewhat stereotyped across subjects (r = 0.58 ± 0.31). Differences in task (postural vs. kinetic), limb configuration, and subject characteristics (sex; tremor severity, onset, and duration) had little effect on distribution (r =0.84). Interestingly, the distribution of tremorogenic activity was highly correlated (r = 0.94 ± 0.08) with the distribution of voluntary activity (power between 0.5 and 4 Hz). In particular, muscles opposing gravity had the highest amount of tremorogenic activity. This may explain in part why the distribution of tremorogenic activity was stereotyped across subjects.
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Erickson-Davis, Cordelia R. « Neurofeedback training for Parkinsonian tremor and bradykinesia / ». Connect to online version, 2006. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2006/153.pdf.
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Chao, Kevin Tzu-Kai. « Global search of triggered non-volcanic tremor ». Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44779.
Texte intégralRésumé :
Deep non-volcanic tremor is a newly discovered seismic phenomenon with low amplitude, long duration, and no clear P- and S-waves as compared with regular earthquake. Tremor has been observed at many major plate-boundary faults, providing new information about fault slip behaviors below the seismogenic zone. While tremor mostly occurs spontaneously (ambient tremor) or during episodic slow- slip events (SSEs), sometimes tremor can also be triggered during teleseismic waves of distance earthquakes, which is known as "triggered tremor". The primary focus of my Ph.D. work is to understand the physical mechanisms and necessary conditions of triggered tremor by systematic investigations in different tectonic regions. These include Taiwan, California, southwest Japan, Alaska and the Aleutian Arc, Cascadia, and New Zealand.
In the first chapter of my dissertation, I conduct a systematic survey of triggered tremor beneath the Central Range (CR) in Taiwan for 45 teleseismic earthquakes from 1998 to 2009 with Mw ≥ 7.5. Triggered tremors are visually identified as bursts of high-frequency (2-8 Hz), non-impulsive, and long-duration seismic energy that are coherent among many seismic stations and modulated by the teleseismic surface waves. A total of 9 teleseismic earthquakes has triggered clear tremor in Taiwan. The peak ground velocity (PGV) of teleseismic surface waves is the most important factor in determining tremor triggering potential, with an apparent threshold of ~0.1 cm/s, or 7-8 kPa. However, such threshold is partially controlled by the background noise level, preventing triggered tremor with weaker amplitude from being observed. In
addition, I find a positive correlation between the PGV and the triggered tremor amplitude, which is consistent with the prediction of the 'clock-advance' model. This suggests that triggered tremor can be considered as a sped-up occurrence of ambient tremor under fast loading from the passing surface waves. Finally, the incident angles of surface waves also play an important rule in controlling the tremor triggering potential.
The next 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 summary, systematically surveys of triggered tremor in different tectonic regions reveal that triggered tremor shares similar physical mechanism (shear failure on the fault interface) as ambient tremor but with different loading conditions. The amplitude of the teleseismic surface wave is one of the most important factors in controlling the tremor triggering threshold. In addition, the frequency contents and incident angles of the triggering waves, and local fault geometry and ambient conditions also play certain roles in determining the triggering potential. On the other hand, the background noise level and seismic network coverage and station quality also could affect the apparent triggering threshold.
Because triggered tremor occurs almost instantaneously during the teleseismic surface waves, and the tremor amplitude is somewhat controlled by the amplitude of the triggering waves, the occurrence time and the size of the triggered tremor could be somewhat predictable, so long as we know the amplitude and period of surface waves and associated time-varying dynamic stresses. Hence, further analysis of triggered tremor may provide important new clues on the nucleation and predictability of seismic events.
22
Unglert, Katharina Claudia. « Towards a global classification of volcanic tremor ». Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58710.
Texte intégralRésumé :
Volcanic tremor, a seismic signal with longer durations and lower frequency content compared to local earthquakes, is often observed before or during eruptions and may consequently be useful for eruption forecasting. However, the processes generating volcanic tremor are still poorly understood. The main goal of this thesis is to assess systematic similarities and differences among tremor from a global sample of volcanoes, which is crucial to successfully constrain plausible source mechanisms. Using time series analysis of seismic signals accompanying three eruptive episodes at Kīlauea Volcano, Hawai‘i, I show that two characteristic phases of seismicity accompany dike intrusions, and that a different type of tremor occurs during a period of explosive activity. The signals differ in their spatial, temporal, and most strongly in their spectral properties. I thus construct a synthetic dataset of spectra that mimic the different spectral shapes observed in Hawai‘i. I use this dataset to evaluate the performance of two pattern recognition algorithms that may facilitate a global comparison of volcanic tremor spectra. A variety of tests with the synthetic spectra including different numbers and character of spectral patterns, as well as increasing levels of noise reveal that Principal Component Analysis and hierarchical clustering, in combination with a newly developed criterion to determine the ideal number of groupings in the data, can successfully identify the correct number and character of the known spectra. I thus develop a detection algorithm for volcanic tremor and apply the pattern recognition approach to detect patterns in tremor spectra from Kīlauea, Okmok, Pavlof, and Redoubt volcanoes. By analyzing the station network for each volcano individually, I show that tremor has distinct spatial and temporal characteristics for each of the volcanic settings. A subsequent comparative analysis suggests that several volcanic settings share common spectral tremor characteristics. I identify at least four types of volcanic tremor with systematic variations among the four settings, which indicates relationships to volcanic controls such as magma storage depth and viscosity. Further analysis of tremor from a larger sample of volcanoes will help to constrain plausible source processes and ultimately improve eruption forecasting.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
23
Alusi, Sundus Husni. « A study of tremor in multiple sclerosis ». Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248405.
Texte intégral
24
Harris, E. « A statistical analysis of hand tremor data ». Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378117.
Texte intégral
25
Copur, Engin H. « Repetitive control for FES-based tremor suppression ». Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/419405/.
Texte intégralRésumé :
Tremor is an involuntary, rhythmic movement of one or more body parts which prevents patients from performing activities of daily living (ADL), thereby greatly diminishing quality of life. Although there are various methods to suppress tremor, each is limited by either cost, ability to produce sufficient tremor suppression (TS) or interference with voluntary action. Functional electrical stimulation (FES) has attracted significant research attention as a novel approach for TS, and has substantial potential advantage in terms of cost, convenience and size. Results from previous studies have demonstrated that FES controlled by classical control methods is unable to produce satisfactory TS, while also producing intense interference with voluntary action. Thus their performance is inherently limited by the drawbacks of conventional feedback design. Since repetitive control (RC) is able to reject a periodic disturbance completely and tremor can be regarded as a periodic disturbance, RC may have more potential for TS than other classical feedback control techniques. This thesis thus provides the first thorough implementation and assessment of RC for TS by means of FES in order to establish its feasibility and performance advantages compared to the conventional filter techniques (FT) that have so far been employed. Due to the importance of the wrist joint in ADL, wrist movement in flexion/extension is targeted within this programme of research. First, simulations are performed using a previously validated linear model of tremulous wrist dynamics to evaluate the feasibility of applying linear RC for TS, and results show that RC is able to produce complete tremor suppression but incurs a severe interference with voluntary action. Since this linear model does not account for the critical properties of the dynamics and RC requires a reliable knowledge of the plant dynamics to guarantee the stability of RC and improve its performance, this thesis then proposes a nonlinear model structure with an identification procedure that maintains the balance between the accuracy and the needs of the clinical domain. Then a linearising control approach is undertaken to enable linear RC design and a mechanism is proposed to preserve the voluntary action which is restricted by applying RC. Analysis confirms that the proposed mechanism can significantly reduce the undesirable interference of RC with voluntary action. Finally, two separate experimental studies are conducted using a test platform. The former is performed to fix the order of the model components in advance to reduce the computational effort of the identification procedure. The response of the wrist joint to FES signals applied to the flexion/extension muscles of each participant is collected. Using these input/output data sets, different models are identified for a number of different orders. Then the fitting accuracies of all models with the same order are averaged and an order is selected with maintaining the balance between model accuracy and simplicity. The second experimental study is to confirm the higher potential of the proposed RC compared with FT for FES-based TS. A mechanical system is introduced to the existing test platform to induce tremor artificially since the participants are unimpaired. The participants are asked to complete three consecutive tests to examine the effect of induced tremor on the ability of patients to perform voluntary task, the capability of FES to suppress the induced tremor and the effect of FES on the voluntary motion. The results indicate that the proposed RC approach with the developed model identification procedure can suppress tremor more effectively than FT and leads to a minimal interference with voluntary motion. This research therefore has established the feasibility of RC for TS by validating the model accuracy, the identification procedure, and the control performance. It has therefore potential for future exploration to provide more effective solutions for patients.
26
Hall, Gary Ellis 1976. « Active tremor control of human motion disorder ». Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/34343.
Texte intégralRésumé :
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 141-142).
All humans are subject to a physiological phenomenon known as tremor, which introduces unintended, relatively high-frequency movements into various parts of the body. These unintended movements serve to limit human motor performance with respect to normal human performance (for cases in which tremor is severe), and with respect to tasks that require "superhuman" performance (for cases in which not even normal tremor is tolerable). For example, the elderly often experience reduced motor control to the point where they can not eat. Similarly, surgeons performing eye surgery must have very little tremor to enable them to operate on the small anatomy of the eyes. In both cases, a motion disorder known as essential tremor can be the cause of the insufficient level of human motor performance. Current treatments for tremor disorders such as essential tremor include a small set of extremes (brain surgery versus doing nothing), with very little "middle ground." A device that could easily be placed onto the body and removed when not needed could fill this niche nicely. Due to the potential for high performance and portability, a new type of tremor stabilizer is proposed that uses a proof mass actuation scheme. This prototype device intended to attenuate human essential tremor along two translational axes was designed, constructed, and tested. Mechanical design, dynamics, and control systems modeling were performed, and the end device built to specifications. A shaker and experimental mount were constructed to artificially simulate tremor, and all data were gathered using this setup. The prototype demonstrated a 4:1 reduction in simulated tremor acceleration power from open- to closed-loop operation, as well as a 2:1 reduction in simulated tremor amplitude from open- to closed-loop operation. Medical personnel at Massachusetts General Hospital have suggested that this level of tremor attenuation would be helpful for their patients. Results were limited to vibrations along one of the two translational axes. Limitations of the prototype are discussed, as well as design strategies to improve performance in future work.
by Gary Ellis Hall.
S.M.
27
Barreto, Ana Catarina da Silva. « Estudo retrospetivo sobre tremor epizoótico em Portugal ». Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2014. http://hdl.handle.net/10400.5/6528.
Texte intégralRésumé :
Dissertação de Mestrado Integrado em Medicina VeterináriaO tremor epizoótico (TE) é uma encefalopatia espongiforme transmissível (EET) que ocorre naturalmente em ovinos, caprinos e muflões. É uma doença conhecida há mais de 250 anos. Caracteriza-se pela acumulação da isoforma patológica- proteína priónica resistente (PrPres ou PrPsc) de uma proteína fisiológica do hospedeiro- proteína priónica celular (PrPc) no sistema nervoso central, conduzindo à progressiva neurodegeneração e morte. O tremor epizoótico ou scrapie, representa o protótipo das doenças priónicas. Existem dois tipos de scrapie classificados até à data, o scrapie clássico e o scrapie atípico/Nor98. A suscetibilidade a qualquer dos tipos de scrapie é determinada por polimorfismos do gene priónico. O scrapie clássico é uma doença infecciosa sendo que o scrapie atípico/Nor98 é visto como uma doença de ocorrência esporádica e dependente da mudança espontânea de conformação da proteína priónica. O tipo de scrapie mais prevalente em Portugal é o scrapie atípico/Nor98. Assim, elaborou-se o presente estudo retrospetivo com o intuito de determinar o potencial de ocorrência de scrapie no nosso país entre 1995 e 2002, examinando, pela técnica de imunohistoquímica (IHQ), amostras de tecido nervoso de pequenos ruminantes arquivadas no Laboratório de Patologia do Instituto Nacional de Investigação Agrária e Veterinária (INIAV), e contribuir para a caracterização epidemiológica desta doença no nosso país.
ABSTRACT - Retrospective study on scrapie in Portugal - Scrapie is naturally occurring transmissible spongiform encephalopathy (TSE) in sheep, goat and mufflons almost worldwide and it is known for about 250 years. It is characterized by the accumulation of an abnormal isoform- resistant prion protein (PrPres or PrPsc) of host encoded prion protein- cellular prion protein (PrPc) in the central nervous system leading to progressive neurodegeneration and death. Scrapie represents the prototype of the so-called prion diseases. It is observed to date as two types, classical and atypical/Nor98 scrapie. The susceptibility to both types is modulated by polymorphisms of the prion gene. Whereas classical scrapie is clearly a naturally occurring transmissible disease, atypical scrapie seems to be caused by spontaneous misfolding of prion protein. The most prevalent type of scrapie in Portugal is the atypical/Nor 98 strain. This retrospective study intends to find out the potential occurrence of scrapie in Portugal before 2002, examining through imunohistochemistry (IHC) samples of small ruminants archived from 1995 to 2002 in the Pathology laboratory from INIAV (Instituto Nacional de Investigação Agrária e Veterinária – The National Institute for Agricultural and Veterinary Research), contributing to the epidemiological characterization of the disease in this country.
28
Chen, Albert C. « Analysis of the rehabilitation of tremor patients ». Thesis, Massachusetts Institute of Technology, 1991. https://hdl.handle.net/1721.1/129502.
Texte intégralRésumé :
Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1991.Title as it appears in the June, 1991 M.I.T. Graduate List: Analysis of the rehabilitation industry for tremor patients.
Includes bibliographical references.
by Albert Chen.
Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1991.
29
Fois, Alessandro Francesco. « Tremor classification and measurement : insights from neurophysiology ». Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29841.
Texte intégralRésumé :
Tremor is a common problem, affecting perhaps 1% of the human population, and often manifests in the upper limbs where it can interfere with hand function and cause social embarrassment. The assessment and classification of human tremor into diagnostic categories remains predominantly clinical, leading to inter-observer inconsistencies that blur the diagnostic labels used in research and clinical practice and hamper both endeavours. In this thesis, I explore the use of neurophysiological techniques in a series of related studies to provide an objective method of measuring tremor and gaining insight into its biological underpinnings.
In order to explore the mechanism of Parkinsonian tremor, a cohort of participants with Parkinson's disease (PD) and tremor were studied using surface electromyography (sEMG), accelerometry, and dopamine transporter imaging (TRODAT-1 SPECT). Parkinsonian rest tremor was shown to correlate to contralateral reduction in striatal dopamine binding, a relationship that provides insight into the mechanism of rest tremor in Parkinson’s disease (PD) and was not found by previous studies that relied on clinical assessment of tremor.
In a separate cohort of participants with common tremor syndromes including Parkinson's disease, essential tremor (ET), dystonic tremor (DT), and essential tremor plus (ET plus), several neurophysiological markers were studied including sEMG and accelerometry, with the development of new metrics to quantify tremor symmetry and relative tremor power under different conditions (e.g. rest vs posture); and neurophysiological markers unrelated to tremor kinematics (but giving insight into the tremor mechanism or presence of dystonia), including the long-latency reflex (LLR), temporal discrimination threshold (TDT) and tonic vibration reflex (TVR). Several neurophysiological markers were shown to distinguish PD from other tremor types including lower tremor stability index (TSI), higher rest tremor asymmetry, higher ratio of rest to postural tremor power, and more regular EMG tremor bursts. In order to address current inter-observer inconsistencies in the classification of action upper limb tremor (DT, ET, ET plus), I performed an unsupervised cluster analysis using neurophysiological data from these participants. Using the ratio of tremor power at rest compared to posture (Rest-Posture Index; RPI) I was able to generate a DT-enriched cluster with muscle coherence characteristics typical of dystonia. Cluster analysis using all neurophysiological parameters generated an ET/ET-plus only cluster with different neurophysiological characteristics. These cluster analysis results provide objective neurophysiological evidence of a subdivision within action tremor syndromes as a whole, even though the current clinical classification system (into categories of DT, ET, and ET plus) may be inconsistent with this subdivision.
Finally, looking beyond conventional neurophysiology, data (sEMG, accelerometry, and video) from this same cohort were used to validate the measurement of tremor with automated video analysis, using the open-source pose estimation platform OpenPose. I demonstrated that OpenPose applied to videos of tremor provides an effective tool for the measurement of rest tremor and has the potential to expand access to objective tremor measurement beyond the neurophysiology laboratory.
30
Wolz, Martin, Antje Hähner, Linda Meixner, Matthias Löhle, Heinz Reichmann, Thomas Hummel et Alexander Storch. « Accurate Detection of Parkinson’s Disease in Tremor Syndromes Using Olfactory Testing ». Karger, 2014. https://tud.qucosa.de/id/qucosa%3A70557.
Texte intégralRésumé :
Background/Aims: The diagnostic value of olfactory testing for the discrimination of tremor-dominant Parkinson’s disease (PD) from other tremor disorders remains enigmatic. We evaluated whether olfactory testing can accurately detect PD in tremor patients. Methods: A
retrospective analysis of 299 consecutive subjects referred for the differential diagnosis of a tremor disorder was done. Olfactory testing was performed using ‘Sniffin’ Sticks’, resulting in a composite TDI score of odor threshold (T), discrimination (D), and identification (I). Receiver operating curve (ROC) plots were used to calculate sensitivity/specificity for the detection of PD. Results: Of all subjects, 167 (55.9%) had PD and 85 (28.4%) had essential tremor (ET). The mean TDI score in PD was significantly reduced compared to those in ET and other tremor disorders with no differences between ET and other tremor disorders. ROC analysis revealed strong correlations of TDI scores with PD [area under the curve: 0.85 (95% CI: 0.80–0.89); p < 0.001]. The highest Youden index was observed for a TDI score <25 (Youden index: 0.58). Using this cutoff score and that generated from normative data of healthy controls, the TDI score provided high sensitivity (negative predictive value) and specificity (positive predictive value) of approximately 80% for detecting PD. Conclusion: Olfactory testing is a useful, easily applied and inexpensive diagnostic test which is helpful to detect PD among tremor patients.
31
Maryanto, Sukir. « Mechanisms of harmonic tremors at Sakurajima volcano, Japan ». 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136775.
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32
Spyers-Ashby, Julia Mary. « The recording and analysis of tremor in neurological disorders ». Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286132.
Texte intégral
33
Muqdisi, Menhal. « Development of equipment for measuring Ocular Micro-Tremor ». Thesis, Mälardalen University, School of Innovation, Design and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-5718.
Texte intégral
34
Saifee, T. A. « The clinical spectrum and pathophysiology of neuropathic tremor ». Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1472932/.
Texte intégralRésumé :
This thesis describes a series of studies involving patients with neuropathies and healthy controls. In the studies of disease, two groups were recruited: patients with inflammatory neuropathies and those with hereditary neuropathies. Each group was separated into those with and those without tremor and compared with healthy controls. Clinical assessments and neurophysiological tests were employed to correlate cerebellar function with tremor. The final study of healthy participants investigated the effect of transcranial direct current stimulation (TDCS) on the cerebellum during finger tapping. 1) Tremor was most common in IgM paraproteinaemic neuropathies, also occurring in 58% of those with chronic inflammatory demyelinating polyradiculoneuropathy and 56% of those with multifocal motor neuropathy with conduction block (MMNCB). Tremor was generally refractory to treatment and contributed to disability in some patients. Although tremor severity correlated with F wave latency, it was insufficient to distinguish those with, from those without tremor. 2) Impaired eyeblink classical conditioning and paired associative stimulation in patients with inflammatory neuropathy and tremor differentiated them from neuropathy patients without tremor and healthy controls, strongly suggesting impairment of cerebellar function is linked to the production of tremor in these patients. 3) The prevalence study in CMT1A patients revealed tremor in 21% and in 42% of those it caused impairment. Eyeblink conditioning, visuomotor adaptation and electro-oculography were no different between tremulous and non-tremulous patients and healthy controls. This argues against a prominent role for an abnormal cerebellum in tremor generation in the patients studied. Rather, they suggest an enhancement of the central neurogenic component of physiological tremor as a possible mechanism. 4) TDCS of the lateral cerebellum and its effect on paced finger tapping was examined. There was no effect on accuracy or variability of the intertap interval, providing no support for a direct role of the cerebellum in event based timing.
35
Vernooij, Carlijn Andrea. « The role of mechanical resonance in physiological tremor ». Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5006/.
Texte intégralRésumé :
The origin of physiological tremor has been studied for many years. Several central and spinal mechanisms which provide an oscillatory input to the muscles have been proposed. Nevertheless, any neural control signal inevitably has to work upon a resonant peripheral system involving the series-coupled elastic muscle-tendon complex and the inertia of the limb. In this thesis I look into the potential role for mechanical resonance to explain tremor. First, I show that the resonant component of hand tremor depends on the velocity of hand movement. Movement reduces muscle stiffness (a process called muscle thixotropy) and the tremor frequency falls. Second, I demonstrate that rhythmic tremor is abolished when eliminating resonance by recording tremor in isometric conditions. Third, I replaced EMG by an artificial drive. This generated tremor which behaved similarly to physiological postural and dynamic tremor. Finally, I studied the relationship between EMG and tremor in the transition from posture to movement. Muscle converts EMG into acceleration differently for static and moving limbs. These findings suggest that there is a key role for mechanical resonance in the generation of physiological tremor. A frequency-specific neural input is not necessary to produce any of the characteristic peaks in postural or dynamic tremor.
36
E, N. Shaban, et V. Abousetta S. « Online EMG signal analysis for Parkinson’s tremor determination ». Thesis, Boston, USA, 2020. http://openarchive.nure.ua/handle/document/11838.
Texte intégralRésumé :
In this paper, we introduced a general development of software for quantifying the severity of the Parkinson's tremor. The extracted features from the surface EMG of the wrist and hand muscles were the input of the designed model of the application. Using the application that can record reliably the EMG signals and quantify the levels of tremor may contribute to the early diagnosis of the disorder online.
37
Shaban, N. E., et V. S. Abousetta. « Online EMG signal analysis for Parkinson’s tremor determination ». Thesis, Boston, USA, 2020. http://openarchive.nure.ua/handle/document/13654.
Texte intégralRésumé :
In this paper, we introduced a general development of software for quantifying the severity of the Parkinson's tremor. The extracted features from the surface EMG of the wrist and hand muscles were the input of the designed model of the application. Using the application that can record reliably the EMG signals and quantify the levels of tremor may contribute to the early diagnosis of the disorder online.
38
Hinojosa-Prieto, Hector R. « Subduction zone-related Nonvolcanic Tremor in Oaxaca, Mexico ». Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1242326095.
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39
Lester, Rosemary Anne. « Modulation of Voice Related to Tremor and Vibrato ». Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/325218.
Texte intégralRésumé :
Modulation of voice is a result of physiologic oscillation within one or more components of the vocal system including the breathing apparatus (i.e., pressure supply), the larynx (i.e. sound source), and the vocal tract (i.e., sound filter). These oscillations may be caused by pathological tremor associated with neurological disorders like essential tremor or by volitional production of vibrato in singers. Because the acoustical characteristics of voice modulation specific to each component of the vocal system and the effect of these characteristics on perception are not well-understood, it is difficult to assess individuals with vocal tremor and to determine the most effective interventions for reducing the perceptual severity of the disorder. The purpose of the present studies was to determine how the acoustical characteristics associated with laryngeal-based vocal tremor affect the perception of the magnitude of voice modulation, and to determine if adjustments could be made to the voice source and vocal tract filter to alter the acoustic output and reduce the perception of modulation. This research was carried out using both a computational model of speech production and trained singers producing vibrato to simulate laryngeal-based vocal tremor with different voice source characteristics (i.e., vocal fold length and degree of vocal fold adduction) and different vocal tract filter characteristics (i.e., vowel shapes). It was expected that, by making adjustments to the voice source and vocal tract filter that reduce the amplitude of the higher harmonics, the perception of magnitude of voice modulation would be reduced. The results of this study revealed that listeners' perception of the magnitude of modulation of voice was affected by the degree of vocal fold adduction and the vocal tract shape with the computational model, but only by the vocal quality (corresponding to the degree of vocal fold adduction) with the female singer. Based on regression analyses, listeners' judgments were predicted by modulation information in both low and high frequency bands. The findings from these studies indicate that production of a breathy vocal quality might be a useful compensatory strategy for reducing the perceptual severity of modulation of voice for individuals with tremor affecting the larynx.
40
Cook, Sarah Jane. « Contributions of the larynx to vocal tremor perception ». Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192315.
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41
Davidson, Andrew Doran. « Fundamental Principles of Tremor Propagation in the Upper Limb ». BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6509.
Texte intégralRésumé :
Although tremor is the most common movement disorder, there exist few effective tremor-suppressing devices, in part because the characteristics of tremor throughout the upper limb are unknown. To clarify, optimally suppressing tremor requires a knowledge of the mechanical origin, propagation, and distribution of tremor throughout the upper limb. Here we present the first systematic investigation of how tremor propagates between the shoulder, elbow, forearm, and wrist. We simulated tremor propagation using a linear, time-invariant, lumped-parameter musculoskeletal model relating joint torques and the resulting joint displacements. The model focused on the seven main degrees of freedom (DOF) from the shoulder to the wrist and included coupled joint inertia, damping, and stiffness. We deliberately implemented a simple model to focus first on the most basic effects. Simulating tremorogenic joint torque as a sinusoidal input, we used the model to establish fundamental principles describing how input parameters (torque location and frequency) and joint impedance (inertia, damping, and stiffness) affect tremor propagation. We expect that the methods and principles presented here will serve as the groundwork for future refining studies to understand the origin, propagation, and distribution of tremor throughout the upper limb in order to enable the future development of optimal tremor-suppressing devices.
42
De, Lange Stephanie Siobhan. « Tremors in white rhinoceros (Ceratotherium simum) during chemical immobilisation ». Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/53294.
Texte intégralRésumé :
White rhinoceros (Ceratotherium simum) are susceptible to developing muscle tremors during chemical immobilisation induced by potent opioid receptor agonists. Whether these tremors result directly from the actions of the opioids or from other physiological changes associated with immobilisation is unknown. A pilot study on 8 boma-managed chemically immobilised rhinoceros was conducted using different supportive interventions for the animal?s cardiorespiratory systems to test whether these interventions had an effect on tremors during chemical immobilisation. The pilot study revealed that butorphanol, a partial opioid agonist/antagonist, combined with nasotracheal oxygen insufflation, compared to the control, was the only intervention that decreased the observed tremor intensity and adequately stabilized the rhinoceros cardiorespiratory system in the immobilised rhinoceros. With this knowledge and using the same drug protocol (etorphine and azaperone and hyaluronidase) and supportive interventions (butorphanol and nasotracheal oxygen insufflation), a field study was conducted to quantify tremors, both objectively and subjectively, and record various physiological responses of 14 rhinoceros during a 25 minute chemical immobilisation period. Butorphanol was injected intravenously 6 minutes after the rhinoceros became laterally recumbent. Tracheal oxygen insufflation was also administered from this time. Occurrence (intensity) of tremors was assessed every minute throughout the 25 minute immobilisation period, both subjectively by human observation, and objectively by accelerometer data loggers placed on the front leg. Arterial blood pH, oxygen and carbon dioxide levels, electrolytes and plasma catecholamine concentrations were measured at 5 minute time points. The tremor intensity was highest (5 minutes 28 counts/min) just after the animals became recumbent, but decreased (3 counts/min) after butorphanol and nasotracheal oxygen insufflation was administered. Tremor intensity was correlated with the mean pH, arterial partial pressure of oxygen, serum potassium and median plasma adrenaline concentration. High tremor intensity occurred when plasma adrenaline concentrations were elevated and when hypoxaemia and acidaemia were at their worst. Hypoxaemia and acidaemia, both physiological stressors, were correlated with the increased plasma adrenaline concentrations. These correlations indicate that changes in blood oxygenation and pH could be the driving force behind the changes in the tremor intensity. Butorphanol and nasotracheal oxygen insufflation corrected the hypoxia and acidaemia and reduced tremor intensity. Therefore, tremor intensity could possibly indicate the severity of the pathophysiological effects of the capture drugs on a rhinoceros cardiorespiratory system.Dissertation (MSc)--University of Pretoria, 2015.
tm2016
Paraclinical Sciences
MSc
43
Pigg, Adam Charles. « Distribution of Essential Tremor in the Degrees of Freedom of the Upper Limb ». BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/7212.
Texte intégralRésumé :
This study seeks to understand upper limb tremor in subjects with essential tremor (ET). A thorough understanding of tremor distribution will allow for the more effective development of tremor suppression devices, which offer an alternative to current treatments. Previous studies primarily focused on tremor in the hand only. This study seeks to characterize the distribution of tremor throughout the upper limb.We measured tremor in 25 subjects diagnosed with ET using motion capture, which provided displacement information of the limb during multiple postural and kinetic tasks. Inverse kinematics allowed us to analyze the motion capture data in the 7 major degrees of freedom (DOF) of the upper limb. The power spectral density estimate was used to determine: relative tremor magnitude throughout the DOFs, tremor variation between tasks, variation between subjects, and frequency variations between DOFs. Data analysis revealed that tremor increase is roughly proximal to distal. We also show that tremor magnitude in kinetic tasks is significantly higher than in postural tasks. Although we found some variation in tremor distribution between subjects, the roughly proximal to distal increase in tremor severity holds for several subsets of the study population. Finally, we found that tremor frequency doesn<'>t vary significantly (< 1 Hz) between DOFs, in subjects with severe tremor. Our study shows that tremor distribution is quite stereotyped between subjects with ET. Furthermore, we have shown that tremor is greatest in the distal DOFs. This provides a compelling starting point for the development of future tremor suppression devices.
44
Grimaldi, Giuliana. « Tremor : from pathogenesis to a multimodal brain-computer interface controlling functional electrical stimulation ». Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/241294.
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45
Sandvik, Ulrika. « Stereotactic functional procedures in the treatment of essential tremor ». Doctoral thesis, Umeå universitet, Institutionen för farmakologi och klinisk neurovetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-49178.
Texte intégralRésumé :
Background: Essential tremor (ET) is the most common movement disorder. In cases resistant to pharmacological treatment, functional stereotactic neurosurgery can be an alternative. Lesional surgery has largely been replaced by deep brain stimulation (DBS). The current target of choice is the ventrolateral thalamus (Vim). Vim DBS has generally shown good results, but in some cases it is associated with a suboptimal effect as well as side effects. DBS in the posterior subthalamic area/caudal zona incerta (PSA/cZi) has recently shown promising effects. Recently the role of lesional therapy in selected cases has been discussed. Aim: The aim is to evaluate stereotactic functional procedures in the treatment of ET, with special emphasis on PSA DBS. Further the effects of DBS in the PSA are evaluated. The optimal target is also assessed by evaluating the effect of Vim and PSA DBS in relation to the position of the electrode. An attempt to identify patient-specific factors of prognostic importance for the outcome after DBS will be made. The quality of life (QoL) of patients treated with PSA DBS for ET will be assessed. Finally, the aim is also to analyze retrospectively the long-term outcome of lesional procedures (thalamotomies). Method: The thesis consists of five studies. The optimal electrode location is evaluated in a study analyzing the location of the electrode contact yielding the best effect in Vim DBS and PSA DBS groups. The efficacy of PSA DBS in 21 patients is evaluated in a prospective study. The correlation between outcome, age, tremor grade and gender is established in a prospective study consisting of 68 patients. Finally, the degree of improvement in QoL is determined in 16 patients operated on in the PSA. The very long-term effect of lesional surgery has been investigated in a retrospective study of nine patients who have undergone thalamotomy. Results: In the study of PSA DBS the total score on the Essential Tremor Rating Scale (ETRS) was reduced by 60% compared to the baseline value. Tremor of the arm was improved by 95%. The study evaluating the optimal contact location showed that the best effect was in the PSA in 54% and in the Vim in 12%. The efficacy of DBS was not related to age, gender, or the severity of tremor with regard to the percentage reduction of tremor on stimulation. In patients with a more severe tremor at baseline, a higher degree of residual tremor on stimulation was seen. With regard to QoL, the activities of daily living (ADL) according to the ETRS score were significantly improved, as well as according to the ADL and psychosocial subscores on the Questionnaire for Essential Tremor (QUEST) scale. No significant changes were found on the generic Short Form (SF-36) QoL scale. Thalamotomy had some positive effects, but also a significant amount of side effects that might be attributed to the surgery. Conclusions: The effect of PSA DBS was very satisfying and compares well with the results from Vim DBS. When both Vim and PSA DBS are considered, the optimal target seems to be located in the PSA. PSA DBS shows good results in improving ADL, but the results have been difficult to demonstrate on QoL scales. The efficacy of DBS could not be shown to be associated with gender or age. Nor was it associated with the severity of tremor regarding the percentage of tremor reduction on stimulation. The preoperative severity of tremor was the most important factor regarding outcome following DBS. With regard to thalamotomies, some possible remaining benefit of the surgery could be seen along with some severe side effects.
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Higenbottam, Colin. « Investigation of the genesis of physiological and shivering tremor ». Thesis, University of Surrey, 1992. http://epubs.surrey.ac.uk/843520/.
Texte intégralRésumé :
An investigation of the spectral characteristics of physiological tremor and cold-induced shivering tremor in the limbs of healthy subjects was conducted. Recordings of posture-maintaining index finger and hand tremor motion were made using miniature accelerometers, together with emg activity in associated superficial extensor and flexor muscles. The effects on physiological finger and hand tremor spectra of systematically applied external inertial and force loads were studied. Comparison was made of bilateral index finger tremor spectra in three characteristic frequency bands. Estimates were also made of the variation of hand tremor frequency with time. The results showed that the dominant responses to modified limb inertia were representative of those of a second order mass-spring mechanism. In contrast, tremor frequency changes consequent upon externally imposed changes in muscle stiffness were not identifiable with this simple mechanism, suggestive of the existence of muscle tone-mediated action of a reflex loop. Measurement of bilateral finger tremor showed no evidence for a common tremor site at the same segmental level. Significant, random changes with time of postural hand tremor frequency were observed. The variation of frequency with time was smaller at higher levels of externally imposed muscle tension. Using a variety of methods of cooling, shivering was induced in 6 subjects and a descriptive analysis was made of hand and upper arm tremor, both in one arm and bilaterally. An experiment was conducted to detect shivering responses to external localised cooling of the spine. The results showed that synchronous co-contraction of limb flexor/extensor muscles was not universally present during shivering, that shivering was invariably accompanied by an increase in the mean level of muscle activity and that steady preshivering muscle tone was often absent between episodes of shivering. Comparison of bilateral upper arm tremor signals showed that shivering was frequently evident at different frequencies without coherence. No shivering responses were detected when the spine was locally cooled to a temperature comparable with that when shivering was evoked by whole-body cooling. It is concluded that the rhythm of both types of limb muscle tremor is predominantly the result of the excitation and regenerative oscillation of a resonant structure under the influence of the highly adaptive spinal reflex arc. It is also recognised that the observation of wide variability between the subjects' responses may signal the action of additional factors on tremor characteristics.
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Mertens, Christophe. « Analysis of vocal tremor in normophonic and dysphonic speakers ». Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/218423.
Texte intégralRésumé :
The study concerns the analysis of vocal cycle length perturbations in normophonic and dysphonic speakers.A method for tracking cycle lengths in voiced speech is proposed. The speech cycles are detected via the saliences of the speech signal samples, defined as the length of the temporal interval over which a sample is a maximum. The tracking of the cycle lengths is based on a dynamic programming algorithm that does not request that the signal is locally periodic and the average period length known a priori.The method is validated on a corpus of synthetic stimuli. The results show a good agreement between the extracted and the synthetic reference length time series. The method is able to track accurately low-frequency modulations and ast cycle-to-cycle perturbations of up to 10% and 4% respectively over the whole range of vocal frequencies. Robustness with regard to the background noise has lso been tested. The results indicate that the tracking is reliable for signal-to-noise ratios higher than 15dB.A method for analyzing the size of the cycle length perturbations as well as their frequency is proposed. The cycle length time series is decomposed into a sum of oscillating components by empirical mode decomposition the instantaneous envelopes and frequencies of which are obtained via AM-FM decomposition. Based on their average instantaneous frequencies, the empirical modes are then assigned to four categories (declination, physiological tremor, neurological tremor as well as cycle length jitter) and added within each. The within-category size of the cycle length perturbations is estimated via the standard deviation of the empirical mode sum divided by the average cycle length. The neurological tremor modulation frequency and bandwidth are obtained via the instantaneous frequencies and amplitudes of empirical modes in the neurological tremor category and summarized via a weighted instantaneous frequency probability density, compensating for the effects of mode mixing.The method is applied to two corpora of vowels comprising 123 and 74 control and 456 and 205 Parkinson speaker recordings respectively. The results indicate that the neurological tremor modulation depth is statistically significantly higher for female Parkinson speakers than for female control speakers. Neurological tremor frequency differs statistically significantly between male and female speakers and increases statistically significantly for the pooled Parkinson speakers compared to the pooled control speakers. Finally, the average vocal frequency increases for male Parkinson speakers and decreases for female Parkinson speakers, compared to the control speakers.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Hilo, Jessica Tayseer. « Inspiratory Breathing Exercises for Vocal Tremor : A Preliminary Study ». Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4074.
Texte intégralRésumé :
Essential voice tremor (EVT) is a voice disorder that results from dyscoordination within the laryngeal musculature, which negatively impacts the symmetrical motion of the vocal folds. Several investigators have shown that individuals with EVT experience difficulty speaking and a reduced quality of life (QOL; Cohen, Dupont, & Courey, 2006; Verdonck-de Leeuw & Mahieu, 2004). While traditional voice therapy has been ineffective in lessening the severity of vocal tremor, a current approach (Barkmeier- Kraemer, Lato, & Wiley, 2011) designed to lessen the perception of vocal tremor has resulted in reported patient satisfaction with little actual change in voice quality. The present study focused on achieving positive voice changes by targeting the physiological aspects of voice production that may be altered through inspiratory breathing techniques, i.e., increased lung volume pressure and laryngeal lowering. The hypothesis was that such changes could result in reductions in vocal tremor and lead to perceived improvements in voice quality and concomitant increases in the participant's QOL.
An ABAB (treatment reversal) single subject design was used to assess the effectiveness of inspiratory breathing exercises on reducing the severity of tremor in three women diagnosed with EVT. Pre-treatment measures were administered, and participant progress was determined after one week of treatment (post-treatment #1), a week of no treatment, and another week of treatment (post-treatment #2). The following measures were gathered from each participant to document treatment progress and effectiveness:lung pressure volume levels, Voice Handicap Index (VHI) ratings, acoustic analyses of isolated vowels, and perceptual ratings on the Consensus Auditory Perceptual Evaluation of Voice (CAPE-V), as well as untrained listener ratings of vocal steadiness and pleasantness.
Physiological, QOL, acoustic, and perceptual data did not triangulate to demonstrate treatment effectiveness. However, individual treatment effects were found in increases in lung pressure volume for participant 1, decreases in CAPE-V scores for participant 3, and decreases in VHI scores for participants 1 and 3. Changes in voice acoustics and untrained listener perceptions were negligible. Thus, the results from this study indicate that inspiratory breathing exercises may show some promise in improving voice and QOL in certain tremor patients and that this technique warrants further research consideration.
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Sun, Wei-Fang. « Detecting deep tectonic tremor in Taiwan using dense arrays ». Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54251.
Texte intégralRésumé :
Deep tectonic tremor has been observed in major subduction zones, strike-slip faults, inland faulting systems, and arc-continent collision environments around the Pacific Rim. However, detailed space-time evolution of its source locations remains enigmatic because of difficulties in detecting and locating tremor accurately. In 2011, we installed two dense, small-aperture seismic arrays aiming to detect ambient tremor source beneath southern Central Range in Taiwan. We recorded continuous waveforms for a total of 134 days, including tremor triggered by the great 2011 Mw9.0 Tohoku earthquake. We use the broadband frequency-wavenumber beamforming and the moving-window grid-search methods to compute array parameters for detecting seismic signals. The obtained array parameters closely match both relocated local earthquakes and triggered tremor bursts located by an envelope cross-correlations method, indicating the robustness of our array technique. We identify tremor signals with coherent waveforms and deep incidence angles and detect tremor for 44 days among the 134-day study period. The total duration is 1,481-minute, which is 3-6 times more than that detected by the envelope cross-correlations method. In some cases, we observe rapid tremor migration with a speed at the order of 40-50 km/hour that is similar to the speed of fast tremor migration along-dip on narrow streaks in Japan and Cascadia. Our results suggest that dense array techniques are capable of capturing detailed spatiotemporal evolutions of tremor behaviors in southern Taiwan.
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Khanna, Tania. « Low power data acquisition for microImplant biometric monitoring of tremors ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78448.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 97-100).
In recent years, trends in the medical industry have created a growing demand for implantable medical devices. In particular, the need to provide doctors a means to continuously monitor biometrics over long time scales with increased precision is paramount to efficient healthcare. To make medical implants more attractive, there is a need to reduce their size and power consumption. Small medical implants would allow for less invasive procedures, greater comfort for patients, and increased patient compliance. Reductions in power consumption translate to longer battery life. The two primary limitations to the size of small medical implants are the batteries that provide energy to circuit and sensor components and the antennas that enable wireless communication to terminals outside of the body. The theory is applied in the context of the long term monitoring of Parkinson's tremors. This work investigates how to reduce the amount of data needing to acquire a signal by applying compressive sampling thereby alleviating the demand on the energy source. A low energy SAR ADC is designed using adiabatic charging to further reduce energy usage. This application is ideal for adiabatic techniques because of the low frequency of operation and the ease with which we can reclaim energy from discharging the capacitors. Keywords: SAR ADC, adiabatic, compressive sampling, biometric, implants
by Tania Khanna.
Ph.D.