1
|
Ni CL, Lin YT, Lu LY, Wang JH, Liu WC, Kuo SH, Pan MK. Tracking motion kinematics and tremor with intrinsic oscillatory property of instrumental mechanics. Bioeng Transl Med 2023; 8:e10432. [PMID: 36925695 PMCID: PMC10013767 DOI: 10.1002/btm2.10432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/10/2022] [Indexed: 11/11/2022] Open
Abstract
Tracking kinematic details of motor behaviors is a foundation to study the neuronal mechanism and biology of motor control. However, most of the physiological motor behaviors and movement disorders, such as gait, balance, tremor, dystonia, and myoclonus, are highly dependent on the overall momentum of the whole-body movements. Therefore, tracking the targeted movement and overall momentum simultaneously is critical for motor control research, but it remains an unmet need. Here, we introduce the intrinsic oscillatory property (IOP), a fundamental mechanical principle of physics, as a method for motion tracking in a force plate. The overall kinetic energy of animal motions can be transformed into the oscillatory amplitudes at the designed IOP frequency of the force plate, while the target movement has its own frequency features and can be tracked simultaneously. Using action tremor as an example, we reported that force plate-based IOP approach has superior performance and reliability in detecting both tremor severity and tremor frequency, showing a lower level of coefficient of variation (CV) compared with video- and accelerometer-based motion tracking methods and their combination. Under the locomotor suppression effect of medications, therapeutic effects on tremor severity can still be quantified by dynamically adjusting the overall locomotor activity detected by IOP. We further validated IOP method in optogenetic-induced movements and natural movements, confirming that IOP can represent the intensity of general rhythmic and nonrhythmic movements, thus it can be generalized as a common approach to study kinematics.
Collapse
Affiliation(s)
- Chun-Lun Ni
- Department of Neurology Columbia University New York New York USA.,The Initiative for Columbia Ataxia and Tremor New York New York USA.,Department of Biochemistry and Molecular Biology Indiana University School of Medicine Indianapolis Indiana USA
| | - Yi-Ting Lin
- Molecular Imaging Center, National Taiwan University Taipei City Taiwan.,Department of Psychology National Taiwan University Taipei City Taiwan
| | - Liang-Yin Lu
- Molecular Imaging Center, National Taiwan University Taipei City Taiwan.,Institute of Biomedical Sciences, Academia Sinica Taipei City Taiwan
| | - Jia-Huei Wang
- Molecular Imaging Center, National Taiwan University Taipei City Taiwan.,Institute of Biomedical Sciences, Academia Sinica Taipei City Taiwan.,Department and Graduate Institute of Pharmacology National Taiwan University College of Medicine Taipei City Taiwan
| | - Wen-Chuan Liu
- Molecular Imaging Center, National Taiwan University Taipei City Taiwan.,Institute of Biomedical Sciences, Academia Sinica Taipei City Taiwan.,Department and Graduate Institute of Pharmacology National Taiwan University College of Medicine Taipei City Taiwan
| | - Sheng-Han Kuo
- Department of Neurology Columbia University New York New York USA.,The Initiative for Columbia Ataxia and Tremor New York New York USA
| | - Ming-Kai Pan
- Molecular Imaging Center, National Taiwan University Taipei City Taiwan.,Institute of Biomedical Sciences, Academia Sinica Taipei City Taiwan.,Department and Graduate Institute of Pharmacology National Taiwan University College of Medicine Taipei City Taiwan.,Department of Medical Research National Taiwan University Hospital Taipei City Taiwan.,Cerebellar Research Center National Taiwan University Hospital, Yun-Lin Branch Yun-Lin Taiwan
| |
Collapse
|
2
|
Louis ED. Essential tremor. HANDBOOK OF CLINICAL NEUROLOGY 2023; 196:389-401. [PMID: 37620080 DOI: 10.1016/b978-0-323-98817-9.00012-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Essential tremor (ET) is a chronic and progressive neurologic disease. Its central and defining clinical feature is a 4-12Hz kinetic tremor, that is, tremor that occurs during voluntary movements such as drinking from a cup or writing. Patients may also exhibit a range of other tremors-postural, rest, intention, additional motor features (e.g., mild gait ataxia, mild dystonia), as well as nonmotor features. The disease itself seems to be a risk factor for other degenerative diseases such as Alzheimer's disease and Parkinson's disease. Both genetic and toxic environmental factors have been explored as etiologic factors. In addition to a growing appreciation of the presence of clinical, etiologic, and pathologic heterogeneity, there is some support for the notion that ET itself may not be a single disease, but may be a family of diseases whose central defining feature is kinetic tremor of the arms, and which might more accurately be referred to as "the essential tremors." Recent research has increasingly placed the seat of the disease in the cerebellum and cerebellar system and identified a host of neurodegenerative changes within the cerebellum, indicating that this progressive disorder is likely degenerative.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| |
Collapse
|
3
|
Elble RJ, Ondo W. Tremor rating scales and laboratory tools for assessing tremor. J Neurol Sci 2022; 435:120202. [DOI: 10.1016/j.jns.2022.120202] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/08/2021] [Accepted: 02/17/2022] [Indexed: 12/29/2022]
|
4
|
Cho HJ. Is essential tremor a degenerative or an electrical disorder? Electrical disorder. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:103-128. [PMID: 35750360 DOI: 10.1016/bs.irn.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Essential tremor (ET) is one of the most common movement disorders, yet we do not have a complete understanding of its pathophysiology. From a phenomenology standpoint, ET is an isolated tremor syndrome of bilateral upper limb action tremor with or without tremor in other body locations. ET is a pathological tremor that arises from excessive oscillation in the central motor network. The tremor network comprises of multiple brain regions including the inferior olive, cerebellum, thalamus, and motor cortex, and there is evidence that a dynamic oscillatory disturbance within this network leads to tremor. ET is a chronic disorder, and the natural history shows a slow progression of tremor intensity with age. There are reported data suggesting that ET follows the disease model of a neurodegenerative disorder, however whether ET is a degenerative or electrical disorder has been a subject of debate. In this chapter, we will review cumulative evidence that ET as a syndrome is a fundamentally electric disorder. The etiology is likely heterogenous and may not be primarily neurodegenerative.
Collapse
Affiliation(s)
- Hyun Joo Cho
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
| |
Collapse
|
5
|
Pan MK, Kuo SH. Essential tremor: Clinical perspectives and pathophysiology. J Neurol Sci 2022; 435:120198. [PMID: 35299120 PMCID: PMC10363990 DOI: 10.1016/j.jns.2022.120198] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/01/2021] [Accepted: 02/17/2022] [Indexed: 12/12/2022]
Abstract
Essential tremor (ET) is one of the most common neurological disorders and can be highly disabling. In recent years, studies on the clinical perspectives and pathophysiology have advanced our understanding of ET. Specifically, clinical heterogeneity of ET, with co-existence of tremor and other neurological features such as dystonia, ataxia, and cognitive dysfunction, has been identified. The cerebellum has been found to be the key brain region for tremor generation, and structural alterations of the cerebellum have been extensively studied in ET. Finally, four main ET pathophysiologies have been proposed: 1) environmental exposures to β-carboline alkaloids and the consequent olivocerebellar hyper-excitation, 2) cerebellar GABA deficiency, 3) climbing fiber synaptic pathology with related cerebellar oscillatory activity, 4) extra-cerebellar oscillatory activity. While these four theories are not mutually exclusive, they can represent distinctive ET subtypes, indicating multiple types of abnormal brain circuitry can lead to action tremor. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.
Collapse
|
6
|
McGurrin P, Vial F, Osterholt T, Norato G, Khan I, Haubenberger D, Ehrlich D, Hallett M. Physiology of Tremor Reduction by Putting the Hands Together in Essential Tremor. Mov Disord Clin Pract 2021; 9:191-197. [PMID: 35146059 PMCID: PMC8810432 DOI: 10.1002/mdc3.13395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/24/2021] [Accepted: 12/03/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Essential tremor is a common movement disorder, characterized by 4-12 Hz tremor of the hands and arms that can affect many activities of daily living. It has been reported by patients that when performing tasks bimanually their tremor is reduced, but why this happens is unknown. OBJECTIVES We measured patients' tremors in different conditions when performed with 1 hand and 2 hands to observe if bimanual task performance changes the characteristics of the tremor. METHODS A total of 10 patients with essential tremor participated in the study. Electromyographic electrodes were attached bilaterally to the wrist flexor and extensor muscles, and accelerometers were attached to the dorsum of the hands. For each condition, holding a cup, wingbeat, and extending both arms up, data were collected with a single hand and bimanually with the hands touching. RESULTS When the hands were touching, there was a significant decrease in both accelerometric and electromyographic power at the tremor frequency. In addition, there was a decrease in coherence between accelerometer and electromyography on the same side. There was no change in the tremor frequency. CONCLUSIONS Tremor amplitude does decrease when the hands are together. Together, the characteristics underlying the decrease in tremor amplitude may indicate a decrease in power of the central oscillator driving the tremor, which we speculate is attributed to the differences in unimanual and bimanual motor control. However, given the small sample size, we note that future hypothesis-driven studies with an a priori power analysis will be required to further explore this phenomenon.
Collapse
Affiliation(s)
- Patrick McGurrin
- Human Motor Control SectionNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Felipe Vial
- Human Motor Control SectionNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA,Facultad de Medicina Clínica Alemana Universidad del DesarrolloSantiagoChile
| | - Thomas Osterholt
- Human Motor Control SectionNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Gina Norato
- Office of the Clinical DirectorNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Imran Khan
- Wilmington Veterans Administration Medical CenterWilmingtonDelawareUSA
| | - Dietrich Haubenberger
- Human Motor Control SectionNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Debra Ehrlich
- Parkinson's Disease Clinic, Office of the Clinical DirectorNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| | - Mark Hallett
- Human Motor Control SectionNational Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaMarylandUSA
| |
Collapse
|
7
|
Kim J, Wichmann T, Inan OT, DeWeerth SP. Fitts Law-Based Performance Metrics to Quantify Tremor in Individuals with Essential Tremor. IEEE J Biomed Health Inform 2021; 26:2169-2179. [PMID: 34851839 DOI: 10.1109/jbhi.2021.3129989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Current methods of evaluating essential tremor (ET) either rely on subjective ratings or use limited tremor metrics (i.e., severity/amplitude and frequency). In this study, we explored performance metrics from Fitts law tasks that replicate and expand existing tremor metrics, to enable low-cost, home-based tremor quantification and analyze the cursor movements of individuals using a 3D mouse while performing a collection of drawing tasks. We analyzed the 3D mouse cursor movements of 11 patients with ET and three controls, on three computer-based tasksa spiral navigation (SPN) task, a rectangular track navigation (RTN) task, and multi-directional tapping/clicking (MDT)with several performance metrics (i.e., outside area (OA), throughput (TP in Fitts law), path efficiency (PE), and completion time (CT)). Using an accelerometer and scores from the Essential Tremor Rating Assessment Scale (TETRAS), we correlated the proposed performance metrics with the baseline tremor metrics and found that the OA of the SPN and RTN tasks were strongly correlated with baseline tremor severity (R2=0.57 and R2=0.83). We also found that the TP in the MDT tasks were strongly correlated with tremor frequency (R2=0.70). In addition, as the OA of the SPN and RTN tasks was correlated with tremor severity and frequency, it may represent an independent metric that increases the dimensionality of the characterization of an individuals tremor. Thus, this pilot study of the analysis of those with ET-associated tremor performing Fitts law tasks demonstrates the feasibility of introducing a new tremor metric that can be expanded for repeatable multi-dimensional data analyses.
Collapse
|
8
|
Casamento-Moran A, Yacoubi B, Wilkes BJ, Hess CW, Foote KD, Okun MS, Wagle Shukla A, Vaillancourt DE, Christou EA. Quantitative Separation of Tremor and Ataxia in Essential Tremor. Ann Neurol 2020; 88:375-387. [PMID: 32418250 DOI: 10.1002/ana.25781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/19/2020] [Accepted: 05/10/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE This study addresses an important problem in neurology, distinguishing tremor and ataxia using quantitative methods. Specifically, we aimed to quantitatively separate dysmetria, a cardinal sign of ataxia, from tremor in essential tremor (ET). METHODS In Experiment 1, we compared 19 participants diagnosed with ET undergoing thalamic deep brain stimulation (DBS; ETDBS ) to 19 healthy controls (HC). We quantified tremor during postural tasks using accelerometry and dysmetria with fast, reverse-at-target goal-directed movements. To ensure that endpoint accuracy was unaffected by tremor, we quantified dysmetria in selected trials manifesting a smooth trajectory to the endpoint. Finally, we manipulated tremor amplitude by switching DBS ON and OFF to examine its effect on dysmetria. In Experiment 2, we compared 10 ET participants with 10 HC to determine whether we could identify and distinguish dysmetria from tremor in non-DBS ET. RESULTS Three findings suggest that we can quantify dysmetria independently of tremor in ET. First, ETDBS and ET exhibited greater dysmetria than HC and dysmetria did not correlate with tremor (R2 < 0.01). Second, even for trials with tremor-free trajectories to the target, ET exhibited greater dysmetria than HC (p < 0.01). Third, activating DBS reduced tremor (p < 0.01) but had no effect on dysmetria (p > 0.2). INTERPRETATION We demonstrate that dysmetria can be quantified independently of tremor using fast, reverse-at-target goal-directed movements. These results have important implications for the understanding of ET and other cerebellar and tremor disorders. Future research should examine the neurophysiological mechanisms underlying each symptom and characterize their independent contribution to disability. ANN NEUROL 2020;88:375-387.
Collapse
Affiliation(s)
- Agostina Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Basma Yacoubi
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Bradley J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Christopher W Hess
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Kelly D Foote
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Michael S Okun
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Aparna Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA.,Department of Neurology, Fixel Institute for Neurological Diseases, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Evangelos A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| |
Collapse
|
9
|
DeSimone JC, Archer DB, Vaillancourt DE, Wagle Shukla A. Network-level connectivity is a critical feature distinguishing dystonic tremor and essential tremor. Brain 2020; 142:1644-1659. [PMID: 30957839 DOI: 10.1093/brain/awz085] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 11/12/2022] Open
Abstract
Dystonia is a movement disorder characterized by involuntary muscle co-contractions that give rise to disabling movements and postures. A recent expert consensus labelled the incidence of tremor as a core feature of dystonia that can affect body regions both symptomatic and asymptomatic to dystonic features. We are only beginning to understand the neural network-level signatures that relate to clinical features of dystonic tremor. At the same time, clinical features of dystonic tremor can resemble that of essential tremor and present a diagnostic confound for clinicians. Here, we examined network-level functional activation and connectivity in patients with dystonic tremor and essential tremor. The dystonic tremor group included primarily cervical dystonia patients with dystonic head tremor and the majority had additional upper-limb tremor. The experimental paradigm included a precision grip-force task wherein online visual feedback related to force was manipulated across high and low spatial feedback levels. Prior work using this paradigm in essential tremor patients produced exacerbation of grip-force tremor and associated changes in functional activation. As such, we directly compared the effect of visual feedback on grip-force tremor and associated functional network-level activation and connectivity between dystonic tremor and essential tremor patient cohorts to better understand disease-specific mechanisms. Increased visual feedback similarly exacerbated force tremor during the grip-force task in dystonic tremor and essential tremor cohorts. Patients with dystonic tremor and essential tremor were characterized by distinct functional activation abnormalities in cortical regions but not in the cerebellum. We examined seed-based functional connectivity from the sensorimotor cortex, globus pallidus internus, ventral intermediate thalamic nucleus, and dentate nucleus, and observed abnormal functional connectivity networks in dystonic tremor and essential tremor groups relative to controls. However, the effects were far more widespread in the dystonic tremor group as changes in functional connectivity were revealed across cortical, subcortical, and cerebellar regions independent of the seed location. A unique pattern for dystonic tremor included widespread reductions in functional connectivity compared to essential tremor within higher-level cortical, basal ganglia, and cerebellar regions. Importantly, a receiver operating characteristic determined that functional connectivity z-scores were able to classify dystonic tremor and essential tremor with 89% area under the curve, whereas combining functional connectivity with force tremor yielded 94%. These findings point to network-level connectivity as an important feature that differs substantially between dystonic tremor and essential tremor and should be further explored in implementing appropriate diagnostic and therapeutic strategies.
Collapse
Affiliation(s)
- Jesse C DeSimone
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Derek B Archer
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - David E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.,Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.,Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Aparna Wagle Shukla
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.,Fixel Center for Neurological Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| |
Collapse
|
10
|
Sun QY, Xu Q, Tian Y, Hu ZM, Qin LX, Yang JX, Huang W, Xue J, Li JC, Zeng S, Wang Y, Min HX, Chen XY, Wang JP, Xie B, Liang F, Zhang HN, Wang CY, Lei LF, Yan XX, Xu HW, Duan RH, Xia K, Liu JY, Jiang H, Shen L, Guo JF, Tang BS. Expansion of GGC repeat in the human-specific NOTCH2NLC gene is associated with essential tremor. Brain 2019; 143:222-233. [PMID: 31819945 DOI: 10.1093/brain/awz372] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 09/06/2019] [Accepted: 10/04/2019] [Indexed: 12/22/2022] Open
Abstract
Abstract
Essential tremor is one of the most common movement disorders. Despite its high prevalence and heritability, the genetic aetiology of essential tremor remains elusive. Up to now, only a few genes/loci have been identified, but these genes have not been replicated in other essential tremor families or cohorts. Here we report a genetic study in a cohort of 197 Chinese pedigrees clinically diagnosed with essential tremor. Using a comprehensive strategy combining linkage analysis, whole-exome sequencing, long-read whole-genome sequencing, repeat-primed polymerase chain reaction and GC-rich polymerase chain reaction, we identified an abnormal GGC repeat expansion in the 5′ region of the NOTCH2NLC gene that co-segregated with disease in 11 essential tremor families (5.58%) from our cohort. Clinically, probands that had an abnormal GGC repeat expansion were found to have more severe tremor phenotypes, lower activities of daily living ability. Obvious genetic anticipation was also detected in these 11 essential tremor-positive families. These results indicate that abnormal GGC repeat expansion in the 5′ region of NOTCH2NLC gene is associated with essential tremor, and provide strong evidence that essential tremor is a family of diseases with high clinical and genetic heterogeneities.
Collapse
Affiliation(s)
- Qi-Ying Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Qian Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yun Tian
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zheng-Mao Hu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Li-Xia Qin
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jin-Xia Yang
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wen Huang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Jin Xue
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Jin-Chen Li
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Sheng Zeng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ying Wang
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | | | - Xiao-Yu Chen
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jun-Pu Wang
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bin Xie
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fan Liang
- GrandOmics Biosciences, Beijing, China
| | - Hai-Nan Zhang
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chun-Yu Wang
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li-Fang Lei
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xin-Xiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hong-Wei Xu
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ran-Hui Duan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Kun Xia
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China
| | - Jing-Yu Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Center for Human Genome Research, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ji-Feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bei-Sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| |
Collapse
|
11
|
Wilkes BJ, Wagle Shukla A, Casamento-Moran A, Hess CW, Christou EA, Okun MS, Vaillancourt DE. Effects of ventral intermediate nucleus deep brain stimulation across multiple effectors in essential tremor. Clin Neurophysiol 2019; 131:167-176. [PMID: 31794958 DOI: 10.1016/j.clinph.2019.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 09/04/2019] [Accepted: 10/14/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Essential tremor (ET) prominently affects the upper-limbs during voluntary movements, but can also affect the lower-limbs, head, and chin. Although deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of thalamus improves both clinical ratings and quantitative measures of tremor, no study has quantified effects of DBS on tremor across multiple body parts. Our objective was to quantify therapeutic effects of DBS across multiple body parts in ET. METHODS We performed quantitative assessment of tremor in ET patients who had DBS for at least one year. We assessed tremor on and off VIM-stimulation using triaxial accelerometers on the upper-limbs, lower-limbs, head and chin during seated and standing tasks. RESULTS VIM-DBS significantly reduced tremor, but there was no statistical difference in degree of tremor reduction across the measured effectors. Compared to healthy controls, ET patients treated with DBS showed significantly greater tremor power (4-8 Hz) across all effectors during seated and standing tasks. CONCLUSIONS VIM-DBS reduced tremor in ET patients. There was no significant difference in the degree of tremor reduction across the measured effectors. SIGNIFICANCE This study provides new quantitative evidence that VIM-DBS is effective at reducing tremor across multiple parts of the body.
Collapse
Affiliation(s)
- B J Wilkes
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - A Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - A Casamento-Moran
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - C W Hess
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - E A Christou
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - M S Okun
- Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA
| | - D E Vaillancourt
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, Fixel Institute for Neurological Diseases, Movement Disorders and Neurorestoration Program, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
12
|
Archer DB, Coombes SA, Chu WT, Chung JW, Burciu RG, Okun MS, Wagle Shukla A, Vaillancourt DE. A widespread visually-sensitive functional network relates to symptoms in essential tremor. Brain 2019; 141:472-485. [PMID: 29293948 DOI: 10.1093/brain/awx338] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 10/21/2017] [Indexed: 12/17/2022] Open
Abstract
Essential tremor is a neurological syndrome of heterogeneous pathology and aetiology that is characterized by tremor primarily in the upper extremities. This tremor is commonly hypothesized to be driven by a single or multiple neural oscillator(s) within the cerebello-thalamo-cortical pathway. Several studies have found an association of blood-oxygen level-dependent (BOLD) signal in the cerebello-thalamo-cortical pathway with essential tremor, but there is behavioural evidence that also points to the possibility that the severity of tremor could be influenced by visual feedback. Here, we directly manipulated visual feedback during a functional MRI grip force task in patients with essential tremor and control participants, and hypothesized that an increase in visual feedback would exacerbate tremor in the 4-12 Hz range in essential tremor patients. Further, we hypothesized that this exacerbation of tremor would be associated with dysfunctional changes in BOLD signal and entropy within, and beyond, the cerebello-thalamo-cortical pathway. We found that increases in visual feedback increased tremor in the 4-12 Hz range in essential tremor patients, and this increase in tremor was associated with abnormal changes in BOLD amplitude and entropy in regions within the cerebello-thalamo-motor cortical pathway, and extended to visual and parietal areas. To determine if the tremor severity was associated with single or multiple brain region(s), we conducted a birectional stepwise multiple regression analysis, and found that a widespread functional network extending beyond the cerebello-thalamo-motor cortical pathway was associated with changes in tremor severity measured during the imaging protocol. Further, this same network was associated with clinical tremor severity measured with the Fahn, Tolosa, Marin Tremor Rating Scale, suggesting this network is clinically relevant. Since increased visual feedback also reduced force error, this network was evaluated in relation to force error but the model was not significant, indicating it is associated with force tremor but not force error. This study therefore provides new evidence that a widespread functional network is associated with the severity of tremor in patients with essential tremor measured simultaneously at the hand during functional imaging, and is also associated with the clinical severity of tremor. These findings support the idea that the severity of tremor is exacerbated by increased visual feedback, suggesting that designers of new computing technologies should consider using lower visual feedback levels to reduce tremor in essential tremor.
Collapse
Affiliation(s)
- Derek B Archer
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Stephen A Coombes
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Winston T Chu
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.,Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Jae Woo Chung
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Roxana G Burciu
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Michael S Okun
- Department of Neurology and Center for Movement Disorders and Neurorestoration, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Aparna Wagle Shukla
- Department of Neurology and Center for Movement Disorders and Neurorestoration, College of Medicine, University of Florida, Gainesville, FL, USA
| | - David E Vaillancourt
- Laboratory for Rehabilitation Neuroscience, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.,Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.,Department of Neurology and Center for Movement Disorders and Neurorestoration, College of Medicine, University of Florida, Gainesville, FL, USA
| |
Collapse
|
13
|
Nestrasil I, Svatkova A, Rudser KD, Chityala R, Wakumoto A, Mueller BA, Bednařík P, Tuite P, Wu X, Bushara K. White matter measures correlate with essential tremor severity-A pilot diffusion tensor imaging study. Brain Behav 2018; 8:e01039. [PMID: 29964316 PMCID: PMC6085909 DOI: 10.1002/brb3.1039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/15/2018] [Accepted: 06/04/2018] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND An evolving pathophysiological concept of essential tremor (ET) points to diffuse brain network involvement, which emphasizes the need to investigate white matter (WM) changes associated with motor symptoms of ET. OBJECTIVES To investigate ET-related WM changes and WM correlates of tremor severity using tremor clinical rating scales and accelerometry. METHODS Tract-based spatial statistics (TBSS) approach was utilized to compare 3 Tesla diffusion tensor imaging (DTI) data from 12 ET patients and 10 age- and gender-matched healthy individuals. Clinical scales, tremor frequency and amplitude as measured by accelerometry were correlated with DTI data. RESULTS ET patients demonstrated mean (MD) and radial diffusivity (RD) abnormalities in tracts involved in primary and associative motor functions such as bilateral corticospinal tracts, the superior longitudinal fascicles, and the corpus callosum but also in nonmotor regions including the inferior fronto-occipital and longitudinal fascicles, cingulum bundles, anterior thalamic radiations, and uncinate fascicles. A combined tremor frequency and amplitude score correlated with RD and MD in extensive WM areas, which partially overlapped the regions that were associated with tremor frequency. No significant relationship was found between DTI measures and clinical rating scales scores. CONCLUSIONS The results show that ET-related diffusion WM changes and their correlates with tremor severity are preferentially located in the primary and associative motor areas. In contrast, a relationship between WM was not detected with clinical rating scales. Accelerometry parameters may, therefore, serve as a potentially useful clinical measures that relate to WM deficits in ET.
Collapse
Affiliation(s)
- Igor Nestrasil
- Division of Clinical Behavioral NeuroscienceDepartment of PediatricsUniversity of MinnesotaMinneapolisMinnesota
| | - Alena Svatkova
- Division of Clinical Behavioral NeuroscienceDepartment of PediatricsUniversity of MinnesotaMinneapolisMinnesota
- Department of Medicine III, Clinical Division of Endocrinology and MetabolismMedical University of ViennaViennaAustria
- Multimodal and Functional Neuroimaging Research GroupCentral European Institute of TechnologyMasaryk UniversityBrnoCzech Republic
| | - Kyle D. Rudser
- Division of BiostatisticsUniversity of MinnesotaMinneapolisMinnesota
| | | | - Amy Wakumoto
- Division of Clinical Behavioral NeuroscienceDepartment of PediatricsUniversity of MinnesotaMinneapolisMinnesota
| | - Bryon A. Mueller
- Department of PsychiatryUniversity of MinnesotaMinneapolisMinnesota
| | - Petr Bednařík
- Multimodal and Functional Neuroimaging Research GroupCentral European Institute of TechnologyMasaryk UniversityBrnoCzech Republic
- Department of RadiologyCenter for Magnetic Resonance ResearchUniversity of MinnesotaMinneapolisMinnesota
- High Field MR CentreDepartment of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
| | - Paul Tuite
- Department of NeurologyUniversity of MinnesotaMinneapolisMinnesota
| | - Xiang Wu
- Psychology DepartmentSun Yet‐Sen UniversityGuangzhouGuangdongChina
| | - Khalaf Bushara
- Department of NeurologyUniversity of MinnesotaMinneapolisMinnesota
- Neurology ServiceVeterans Affairs Medical CenterMinneapolisMinnesota
| |
Collapse
|
14
|
Benito-León J, Serrano JI, Louis ED, Holobar A, Romero JP, Povalej-Bržan P, Bermejo-Pareja F, Del Castillo MD, Posada IJ, Rocon E. Tremor severity in Parkinson's disease and cortical changes of areas controlling movement sequencing: A preliminary study. J Neurosci Res 2018; 96:1341-1352. [PMID: 29660812 DOI: 10.1002/jnr.24248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/24/2018] [Accepted: 03/26/2018] [Indexed: 11/07/2022]
Abstract
There remains much to learn about the changes in cortical anatomy that are associated with tremor severity in Parkinson's disease (PD). For this reason, we used a combination of structural neuroimaging to measure cortical thickness and neurophysiological studies to analyze whether PD tremor was associated with cortex integrity. Magnetic resonance imaging and neurophysiological assessment were performed in 13 nondemented PD patients (9 women, 69.2%) with a clearly tremor-dominant phenotype. Cortical reconstruction and volumetric segmentation were performed with the Freesurfer image analysis software. Assessment of tremor was performed by means of high-density surface electromyography (hdEMG) and inertial measurement units (IMUs). Individual motor unit discharge patterns were identified from surface hdEMG and tremor metrics quantifying motor unit synchronization from IMUs. Increased motor unit synchronization (i.e., more severe tremor) was associated with cortical changes (i.e., atrophy) in wide-spread cortical areas, including caudal middle frontal regions bilaterally (dorsal premotor cortices), left inferior parietal lobe (posterior parietal cortex), left lateral orbitofrontal cortex, cingulate cortex bilaterally, left posterior and transverse temporal cortex, and left occipital lobe, as well as reduced left middle temporal volume. Given that the majority of these areas are involved in controlling movement sequencing, our results support Albert's classic hypothesis that PD tremor may be the result of an involuntary activation of a program of motor behavior used in the genesis of rapid voluntary alternating movements.
Collapse
Affiliation(s)
- Julián Benito-León
- Department of Neurology, University Hospital 12 de Octubre, Madrid, Spain
- Center of Biomedical Network Research on Neurodegenerative Diseases (CIBERNED), Spain
- Department of Medicine, Faculty of Medicine, Complutense University, Madrid, Spain
| | - J Ignacio Serrano
- Neural and Cognitive Engineering group, Centre for Automation and Robotics (CAR) CSIC-UPM, Arganda del Rey, Spain
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, Connecticut, USA
- Yale School of Medicine and Yale School of Public Health, Center for Neuroepidemiology and Clinical Neurological Research, New Haven, Connecticut, USA
| | - Ales Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Juan P Romero
- Faculty of Biosanitary Sciences, Francisco de Vitoria University, Pozuelo de Alarcón, Madrid, Spain
- Brain Damage Service, Hospital Beata Maria Ana, Madrid, Spain
| | - P Povalej-Bržan
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
- Faculty of Health Sciences, Faculty of Health Sciences, University of Maribor, Maribor, Slovenia
| | - Félix Bermejo-Pareja
- Center of Biomedical Network Research on Neurodegenerative Diseases (CIBERNED), Spain
- Department of Medicine, Faculty of Medicine, Complutense University, Madrid, Spain
- Clinical Research Unit, University Hospital 12 de Octubre, Madrid, Spain
| | - M Dolores Del Castillo
- Neural and Cognitive Engineering group, Centre for Automation and Robotics (CAR) CSIC-UPM, Arganda del Rey, Spain
| | - Ignacio J Posada
- Department of Neurology, University Hospital 12 de Octubre, Madrid, Spain
- Department of Medicine, Faculty of Medicine, Complutense University, Madrid, Spain
| | - Eduardo Rocon
- Neural and Cognitive Engineering group, Centre for Automation and Robotics (CAR) CSIC-UPM, Arganda del Rey, Spain
| |
Collapse
|
15
|
Geiger DW, Eggett DL, Charles SK. A method for characterizing essential tremor from the shoulder to the wrist. Clin Biomech (Bristol, Avon) 2018; 52:117-123. [PMID: 29428341 DOI: 10.1016/j.clinbiomech.2017.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 10/14/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Despite the pervasive and devastating effect of Essential Tremor (ET), the distribution of ET throughout the upper limb is unknown. We developed a method for characterizing the distribution of ET and performed a preliminary characterization in a small number of subjects with ET. METHODS Using orientation sensors and inverse kinematics, we measured tremor in each of the seven major degrees of freedom (DOF) from the shoulder to the wrist while ten patients with mild ET assumed 16 different postures. We described the tremor in each DOF in terms of power spectral density measures and investigated how tremor varied between DOF, postures, gravitational torques, and repetitions. FINDINGS Our method successfully resulted in tremor measures in each DOF, allowing one to compare tremor between DOF and determine the distribution of tremor throughout the upper limb, including how the distribution changes with posture. In our small number of subjects, we found that the amount of power in the frequency band associated with ET (4-12Hz) was lowest in the shoulder and greatest in the wrist. Similarly, the existence and amplitude of peaks in this band increased from proximal to distal. Although the amount of tremor differed significantly between postures, we did not find any clear patterns with changes in posture or gravitational torque. INTERPRETATION This method can be used to characterize the distribution of tremor throughout the upper limb. Our preliminary characterization suggests that the amount of tremor increases in a proximal-distal manner.
Collapse
Affiliation(s)
- Daniel W Geiger
- Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, UT 84602, United States
| | - Dennis L Eggett
- Department of Statistics, Brigham Young University, 223 TMCB, Provo, UT 84602, United States
| | - Steven K Charles
- Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, UT 84602, United States; Neuroscience Center, Brigham Young University, S-192 ESC, Provo, UT 84602, United States.
| |
Collapse
|
16
|
Abstract
Essential tremor (ET) is a progressive and highly prevalent neurologic disease. Along with the tremors, mild to moderate gait ataxia and other signs of cerebellar dysfunction may occur (i.e., subtle saccadic eye movement abnormalities and abnormalities of motor timing) as well as cognitive features, some of which may be due to cerebellar dysfunction. Numerous neuroimaging studies indicate the presence of functional, metabolic, and structural abnormalities in the cerebellum of a patient with ET. In tandem with these clinical and imaging studies, which were gathering increasing support for the notion that the cerebellum and/or cerebellar systems seemed to be at the root of ET, a growing postmortem literature is for the first time beginning to identify microscopic abnormalities in the ET brain, most of which are centered on the Purkinje cells and connected neuronal populations, and are likely to be degenerative. In terms of treatment, most of these pharmacotherapeutic agents serve to enhance GABAergic neurotransmission, further bolstering the notion that ET may very well be a disorder with a primary Purkinje cell dysfunction resulting in reduced cerebellar cortical inhibition. Similarly, the interruption of presumably abnormal cerebellar outflow pathways to the thalamus is the mechanism of deep-brain stimulation surgery, which is highly effective in treating ET.
Collapse
Affiliation(s)
- Elan D Louis
- Department of Neurology and Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, United States; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, United States.
| |
Collapse
|
17
|
Qu HE, Niu CM, Li S, Hao MZ, Hu ZX, Xie Q, Lan N. Neural computational modeling reveals a major role of corticospinal gating of central oscillations in the generation of essential tremor. Neural Regen Res 2017; 12:2035-2044. [PMID: 29323043 PMCID: PMC5784352 DOI: 10.4103/1673-5374.221161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2017] [Indexed: 01/12/2023] Open
Abstract
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.
Collapse
Affiliation(s)
- Hong-en Qu
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chuanxin M. Niu
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Department of Rehabilitation Medicine, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Si Li
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Man-zhao Hao
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zi-xiang Hu
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qing Xie
- Department of Rehabilitation Medicine, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ning Lan
- Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Division of Biokinesiology and Physical Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
18
|
Goubault E, Nguyen HP, Ayachi FS, Bogard S, Duval C. Do Bradykinesia and Tremor Interfere in Voluntary Movement of Essential Tremor Patients? Preliminary Findings. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2017; 7:459. [PMID: 28690920 PMCID: PMC5499257 DOI: 10.7916/d822319x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/23/2017] [Indexed: 12/02/2022]
Abstract
Background The aim of this study was to determine whether tremor and bradykinesia impacted a dexterous activity performed by patients with essential tremor (ET). Methods Core bradykinesia was assessed in 27 controls and 15 patients with ET using a rapid alternating movement (RAM) task. Then, participants performed a “counting money” counting tasks while equipped with inertial measurement units to detect and quantify tremor during movement. The time required to perform subsections of the tasks and the rate of failure (errors) were compared between groups using Mann–Whitney U tests and a chi-square test, respectively. Results Patients with ET presented with significant bradykinesia during the RAM task and had more tremor during the counting money task. However, the time required to perform the task and rate of failure were similar between groups. Discussion Results show that even though bradykinesia was detected during fast movements, and that tremor was present during a task requiring dexterity, both symptoms did not interfere with the performance of patients with ET. This pilot study suggests that there may be a threshold at which tremor will become problematic. Determining this threshold for a wide range of daily activities may help determine when it is appropriate to initiate treatment for patients with ET.
Collapse
Affiliation(s)
- Etienne Goubault
- Département des Sciences de l'activité physique Université du Québec à Montréal, Montréal, Québec, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada
| | - Hung P Nguyen
- Département des Sciences de l'activité physique Université du Québec à Montréal, Montréal, Québec, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada
| | - Fouaz S Ayachi
- Département des Sciences de l'activité physique Université du Québec à Montréal, Montréal, Québec, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada
| | - Sarah Bogard
- Département des Sciences de l'activité physique Université du Québec à Montréal, Montréal, Québec, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada
| | - Christian Duval
- Département des Sciences de l'activité physique Université du Québec à Montréal, Montréal, Québec, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada
| |
Collapse
|
19
|
Zheng X, Vieira Campos A, Ordieres-Meré J, Balseiro J, Labrador Marcos S, Aladro Y. Continuous Monitoring of Essential Tremor Using a Portable System Based on Smartwatch. Front Neurol 2017; 8:96. [PMID: 28360883 PMCID: PMC5350115 DOI: 10.3389/fneur.2017.00096] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/27/2017] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Essential tremor (ET) shows amplitude fluctuations throughout the day, presenting challenges in both clinical and treatment monitoring. Tremor severity is currently evaluated by validated rating scales, which only provide a timely and subjective assessment during a clinical visit. Motor sensors have shown favorable performances in quantifying tremor objectively. METHODS A new highly portable system was used to monitor tremor continuously during daily lives. It consists of a smartwatch with a triaxial accelerometer, a smartphone, and a remote server. An experiment was conducted involving eight ET patients. The average effective data collection time per patient was 26 (±6.05) hours. Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) was adopted as the gold standard to classify tremor and to validate the performance of the system. Quantitative analysis of tremor severity on different time scales is validated. RESULTS Significant correlations were observed between neurologist's FTMTRS and patient's FTMTRS auto-assessment scores (r = 0.84; p = 0.009), between the device quantitative measures and the scores from the standardized assessments of neurologists (r = 0.80; p = 0.005) and patient's auto-evaluation (r = 0.97; p = 0.032), and between patient's FTMTRS auto-assessment scores day-to-day (r = 0.87; p < 0.001). A graphical representation of four patients with different degrees of tremor was presented, and a representative system is proposed to summarize the tremor scoring at different time scales. CONCLUSION This study demonstrates the feasibility of prolonged and continuous monitoring of tremor severity during daily activities by a highly portable non-restrictive system, a useful tool to analyze efficacy and effectiveness of treatment.
Collapse
Affiliation(s)
- Xiaochen Zheng
- Department of Industrial Engineering, Technical University of Madrid , Madrid , Spain
| | | | - Joaquín Ordieres-Meré
- Department of Industrial Engineering, Technical University of Madrid , Madrid , Spain
| | - Jose Balseiro
- University Hospital of Getafe, Getafe , Madrid , Spain
| | | | | |
Collapse
|
20
|
Haubenberger D, Abbruzzese G, Bain PG, Bajaj N, Benito-León J, Bhatia KP, Deuschl G, Forjaz MJ, Hallett M, Louis ED, Lyons KE, Mestre TA, Raethjen J, Stamelou M, Tan EK, Testa CM, Elble RJ. Transducer-based evaluation of tremor. Mov Disord 2016; 31:1327-36. [PMID: 27273470 DOI: 10.1002/mds.26671] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 04/04/2016] [Accepted: 04/07/2016] [Indexed: 11/11/2022] Open
Abstract
The International Parkinson and Movement Disorder Society established a task force on tremor that reviewed the use of transducer-based measures in the quantification and characterization of tremor. Studies of accelerometry, electromyography, activity monitoring, gyroscopy, digitizing tablet-based measures, vocal acoustic analysis, and several other transducer-based methods were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and responsiveness were reviewed for each measure using the following criteria: (1) used in the assessment of tremor; (2) used in published studies by people other than the developers; and (3) adequate clinimetric testing. Accelerometry, gyroscopy, electromyography, and digitizing tablet-based measures fulfilled all three criteria. Compared to rating scales, transducers are far more sensitive to changes in tremor amplitude and frequency, but they do not appear to be more capable of detecting a change that exceeds random variability in tremor amplitude (minimum detectable change). The use of transducer-based measures requires careful attention to their limitations and validity in a particular clinical or research setting. © 2016 International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- Dietrich Haubenberger
- Clinical Trials Unit, Office of the Clinical Director, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
| | | | - Peter G Bain
- Department of Neurology, Imperial College London, Charing Cross Hospital, London, United Kingdom
| | - Nin Bajaj
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Julián Benito-León
- Department of Neurology, University Hospital "12 de Octubre", Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Medicine, Complutense University, Madrid, Spain
| | - Kailash P Bhatia
- Sobell Department for Movement Neuroscience, UCL, Institute of Neurology, Queen Square, London, United Kingdom
| | - Günther Deuschl
- Department of Neurology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Maria João Forjaz
- National School of Public Health and Red de Investigación en Servicios Sanitarios y Enfermedades Crónicas (REDISSEC), Carlos III Institute of Health, Madrid, Spain
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Elan D Louis
- Departments of Neurology and Chronic Disease Epidemiology, Yale School of Medicine and Yale School of Public Health, Yale University, New Haven, Connecticut, USA
| | - Kelly E Lyons
- University of Kansas Medical Center, Kansas City, Kansas
| | - Tiago A Mestre
- Parkinson's disease and Movement Disorders Center, Division of Neurology, Department of Medicine, University of Ottawa, The Ottawa Hospital Research Institute, Ottawa Brain and Mind Research Institute, Ottawa, Ontario, Canada
| | - Jan Raethjen
- Department of Neurology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Maria Stamelou
- Neurology Department, University of Athens, Greece and Neurology Department, Philipps University, Marburg, Germany
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute (SGH campus), Duke NUS Medical School, Singapore General Hospital, Singapore
| | - Claudia M Testa
- Department of Neurology and Parkinson's and Movement Disorders Center, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| |
Collapse
|
21
|
Elble RJ, McNames J. Using Portable Transducers to Measure Tremor Severity. Tremor Other Hyperkinet Mov (N Y) 2016; 6:375. [PMID: 27257514 PMCID: PMC4872171 DOI: 10.7916/d8dr2vcc] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/23/2016] [Indexed: 01/23/2023] Open
Abstract
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.
Collapse
Affiliation(s)
- Rodger J. Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - James McNames
- Department of Electrical and Computer Engineering, Maseeh College of Engineering and Computer Science, Portland State University, Portland, OR, USA
| |
Collapse
|
22
|
Guihard M, Hutin E, Albertsen I, Mardale V, Gracies J. Proposal of tremor quantification method. Ann Phys Rehabil Med 2015. [DOI: 10.1016/j.rehab.2015.07.285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
23
|
The phase difference between neural drives to antagonist muscles in essential tremor is associated with the relative strength of supraspinal and afferent input. J Neurosci 2015; 35:8925-37. [PMID: 26063924 DOI: 10.1523/jneurosci.0106-15.2015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The pathophysiology of essential tremor (ET), the most common movement disorder, is not fully understood. We investigated which factors determine the variability in the phase difference between neural drives to antagonist muscles, a long-standing observation yet unexplained. We used a computational model to simulate the effects of different levels of voluntary and tremulous synaptic input to antagonistic motoneuron pools on the tremor. We compared these simulations to data from 11 human ET patients. In both analyses, the neural drive to muscle was represented as the pooled spike trains of several motor units, which provides an accurate representation of the common synaptic input to motoneurons. The simulations showed that, for each voluntary input level, the phase difference between neural drives to antagonist muscles is determined by the relative strength of the supraspinal tremor input to the motoneuron pools. In addition, when the supraspinal tremor input to one muscle was weak or absent, Ia afferents provided significant common tremor input due to passive stretch. The simulations predicted that without a voluntary drive (rest tremor) the neural drives would be more likely in phase, while a concurrent voluntary input (postural tremor) would lead more frequently to an out-of-phase pattern. The experimental results matched these predictions, showing a significant change in phase difference between postural and rest tremor. They also indicated that the common tremor input is always shared by the antagonistic motoneuron pools, in agreement with the simulations. Our results highlight that the interplay between supraspinal input and spinal afferents is relevant for tremor generation.
Collapse
|
24
|
Gallea C, Popa T, García-Lorenzo D, Valabregue R, Legrand AP, Marais L, Degos B, Hubsch C, Fernández-Vidal S, Bardinet E, Roze E, Lehéricy S, Vidailhet M, Meunier S. Intrinsic signature of essential tremor in the cerebello-frontal network. Brain 2015; 138:2920-33. [PMID: 26115677 DOI: 10.1093/brain/awv171] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/24/2015] [Indexed: 11/12/2022] Open
Abstract
Essential tremor is a movement disorder characterized by tremor during voluntary movements, mainly affecting the upper limbs. The cerebellum and its connections to the cortex are known to be involved in essential tremor, but no task-free intrinsic signatures of tremor related to structural cerebellar defects have so far been found in the cortical motor network. Here we used voxel-based morphometry, tractography and resting-state functional MRI at 3 T to compare structural and functional features in 19 patients with essential tremor and homogeneous symptoms in the upper limbs, and 19 age- and gender-matched healthy volunteers. Both structural and functional abnormalities were found in the patients' cerebellum and supplementary motor area. Relative to the healthy controls, the essential tremor patients' cerebellum exhibited less grey matter in lobule VIII and less effective connectivity between each cerebellar cortex and the ipsilateral dentate nucleus. The patient's supplementary motor area exhibited (i) more grey matter; (ii) a lower amplitude of low-frequency fluctuation of the blood oxygenation level-dependent signal; (iii) less effective connectivity between each supplementary motor area and the ipsilateral primary motor hand area, and (iv) a higher probability of connection between supplementary motor area fibres and the spinal cord. Structural and functional changes in the supplementary motor area, but not in the cerebellum, correlated with clinical severity. In addition, changes in the cerebellum and supplementary motor area were interrelated, as shown by a correlation between the lower amplitude of low-frequency fluctuation in the supplementary motor area and grey matter loss in the cerebellum. The structural and functional changes observed in the supplementary motor area might thus be a direct consequence of cerebellar defects: the supplementary motor area would attempt to reduce tremor in the motor output by reducing its communication with M1 hand areas and by directly modulating motor output via its corticospinal projections.See Raethjen and Muthuraman (doi:10.1093/brain/awv238) for a scientific commentary on this article.
Collapse
Affiliation(s)
- Cécile Gallea
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Traian Popa
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Daniel García-Lorenzo
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Romain Valabregue
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | | | - Lea Marais
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Bertrand Degos
- 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France
| | - Cecile Hubsch
- 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France
| | - Sara Fernández-Vidal
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Eric Bardinet
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| | - Emmanuel Roze
- 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France
| | - Stéphane Lehéricy
- 1 Centre de NeuroImagerie de Recherche - Institut du Cerveau et de la Moelle épinière, ICM, Paris, France 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 7 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neuroradiologie, Paris, France
| | - Marie Vidailhet
- 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France 6 AP-HP, Hôpital de la Pitié Salpêtrière, Département de Neurologie, Paris, France
| | - Sabine Meunier
- 2 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, Paris, France 3 CNRS, UMR 7225, Paris, France 4 Inserm, U 1127, Paris, France
| |
Collapse
|
25
|
Martin JA, Ramsay J, Hughes C, Peters DM, Edwards MG. Age and grip strength predict hand dexterity in adults. PLoS One 2015; 10:e0117598. [PMID: 25689161 PMCID: PMC4331509 DOI: 10.1371/journal.pone.0117598] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/29/2014] [Indexed: 11/18/2022] Open
Abstract
In the scientific literature, there is much evidence of a relationship between age and dexterity, where increased age is related to slower, less nimble and less smooth, less coordinated and less controlled performances. While some suggest that the relationship is a direct consequence of reduced muscle strength associated to increased age, there is a lack of research that has systematically investigated the relationships between age, strength and hand dexterity. Therefore, the aim of this study was to examine the associations between age, grip strength and dexterity. 107 adults (range 18-93 years) completed a series of hand dexterity tasks (i.e. steadiness, line tracking, aiming, and tapping) and a test of maximal grip strength. We performed three phases of analyses. Firstly, we evaluated the simple relationships between pairs of variables; replicating the existing literature; and found significant relationships of increased age and reduced strength; increased age and reduced dexterity, and; reduced strength and reduced dexterity. Secondly, we used standard Multiple Regression (MR) models to determine which of the age and strength factors accounted for the greater variance in dexterity. The results showed that both age and strength made significant contributions to the data variance, but that age explained more of the variance in steadiness and line tracking dexterity, whereas strength explained more of the variance in aiming and tapping dexterity. In a third phase of analysis, we used MR analyses to show an interaction between age and strength on steadiness hand dexterity. Simple Slopes post-hoc analyses showed that the interaction was explained by the middle to older aged adults showing a relationship between reduced strength and reduced hand steadiness, whereas younger aged adults showed no relationship between strength and steadiness hand dexterity. The results are discussed in terms of how age and grip strength predict different types of hand dexterity in adults.
Collapse
Affiliation(s)
- Jason A. Martin
- Functional Neuroimaging Group, Department of Radiology, University Hospital Bonn, Sigmund-Freud Str. 25, 53127, Bonn, Germany
- Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, Centre for Integrative Neuroscience, Eberhard Karls University, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - Jill Ramsay
- School of Health and Population Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Christopher Hughes
- Institute of Sport & Exercise Science, University of Worcester, Worcester, United Kingdom
| | - Derek M. Peters
- Institute of Sport & Exercise Science, University of Worcester, Worcester, United Kingdom
- Faculty of Health & Sport Sciences, University of Agder, Kristiansand, Norway
| | - Martin G. Edwards
- Psychological Sciences Research Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- Institute of Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| |
Collapse
|
26
|
Albertsen I, Hutin E, Mardale V, Gracies JM. A review on tremor quantification methods–Toward rhythmicity measurements? Ann Phys Rehabil Med 2014. [DOI: 10.1016/j.rehab.2014.03.1220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
27
|
Apartis E, Jedynak CP. Tremori. Neurologia 2014. [DOI: 10.1016/s1634-7072(14)66663-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
28
|
Lester RA, Barkmeier-Kraemer J, Story BH. Physiologic and Acoustic Patterns of Essential Vocal Tremor. J Voice 2013; 27:422-32. [DOI: 10.1016/j.jvoice.2013.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 01/07/2013] [Indexed: 10/27/2022]
|
29
|
|
30
|
Gurey LE, Sinclair CF, Blitzer A. A new paradigm for the management of essential vocal tremor with botulinum toxin. Laryngoscope 2013; 123:2497-501. [DOI: 10.1002/lary.24073] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 12/19/2012] [Accepted: 02/02/2013] [Indexed: 11/05/2022]
Affiliation(s)
- Lowell E. Gurey
- New York Center for Voice and Swallowing Disorders; St. Luke's Roosevelt Medical Center; New York; New York; U.S.A
| | - Catherine F. Sinclair
- New York Center for Voice and Swallowing Disorders; St. Luke's Roosevelt Medical Center; New York; New York; U.S.A
| | - Andrew Blitzer
- New York Center for Voice and Swallowing Disorders; St. Luke's Roosevelt Medical Center; New York; New York; U.S.A
| |
Collapse
|
31
|
Abstract
Vocal tremor is a neurogenic voice disorder characterized by a nearly periodic modulation in pitch and loudness during sustained phonation. This voicing pattern is the result of tremor affecting structures within the speech mechanism, resulting in modulation of lung pressure, phonation, articulation, and resonance during speaking. Speaking patterns in these individuals may be perceived as similar to spasmodic dysphonia or muscle tension dysphonia. The key to determining the presence of vocal tremor and distinguishing it from other voice disorders requires familiarity with the perceptual, acoustic, and physiologic patterns associated with vocal tremor during different voicing and speech contexts. Management of those with vocal tremor can be challenging because of its co-occurrence with other neurological disorders. The two most common methods for managing vocal tremor include pharmaceutical treatment, most commonly applied via injections of Botulinum Toxin Type A (Botox®), and behavioral modification of speaking patterns. The latter approach is in early clinical phases of research and has not yet been subjected to clinical trials. In this paper, I will summarize the clinical characteristics of vocal tremor in comparison to what is known about tremor in general and describe Botox® and behavioral approaches for managing individuals with this voice disorder.
Collapse
|
32
|
Mostile G, Fekete R, Giuffrida JP, Yaltho T, Davidson A, Nicoletti A, Zappia M, Jankovic J. Amplitude fluctuations in essential tremor. Parkinsonism Relat Disord 2012; 18:859-63. [DOI: 10.1016/j.parkreldis.2012.04.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/12/2012] [Accepted: 04/15/2012] [Indexed: 11/15/2022]
|
33
|
The usefulness of accelerometric registration with assessment of tremor parameters and their symmetry in differential diagnosis of parkinsonian, essential and cerebellar tremor. Neurol Neurochir Pol 2012; 46:145-56. [DOI: 10.5114/ninp.2012.28257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
34
|
The effect of inertial loading on wrist kinetic tremor and rhythmic muscle activity in individuals with essential tremor. Clin Neurophysiol 2011; 122:1794-801. [DOI: 10.1016/j.clinph.2010.10.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 10/03/2010] [Accepted: 10/28/2010] [Indexed: 02/08/2023]
|
35
|
Machowska-Majchrzak A, Pierzchała K, Pietraszek S, Labuz-Roszak B. Essential tremor - assessment of tremor accelerometric parameters' symmetry and the relationship between hand dominance and severity of tremor. Neurol Neurochir Pol 2011; 45:121-7. [PMID: 21574115 DOI: 10.1016/s0028-3843(14)60022-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND PURPOSE Essential tremor (ET) is likely the most common movement disorder. The aim of the study was to carry out spectral analysis of the essential tremor recorded by an accelerometer and assess the symmetry of tremor parameters between the two hands. MATERIAL AND METHODS We examined 39 patients with ET diagnosed clinically using the criteria of the Movement Disorder Society. The control group consisted of 52 healthy persons. A biaxial accelerometer mounted at the dorsal side of the hand was used. Spectral analysis was performed. Tremor intensity, frequency of spectral peaks, centre frequency, standard deviation of the centre frequency, and harmonic index were measured. The side-to-side symmetry of these parameters was analysed. The relationship of hand dominance and severity of tremor was also analysed. RESULTS There was significant side-to-side asymmetry of intensity in ET. The intensity in the more affected hand was over two times higher than that in the less affected one. The tremor was more severe in the nondominant hand in 62% of patients. In spite of significant difference in tremor intensity between the two sides, tremor frequency was similar in both hands. The standard deviation of centre frequency was significantly lower and the harmonic index was significantly higher in the more trembling hand. CONCLUSIONS Accelerometric registration revealed that asymmetry of intensity and symmetry of frequency are characteristic features of ET. The remaining two coefficients reflecting the rhythmicity and regularity of tremor also differed considerably between the hands.
Collapse
Affiliation(s)
- Agnieszka Machowska-Majchrzak
- Katedra i Klinika Neurologii Śląskiego Uniwersytetu Medycznego w Katowicach, Wydział Lekarski z Oddziałem Lekarsko-Dentystycznym w Zabrzu, ul. 3 Maja 13/15, 41-800 Zabrze.
| | | | | | | |
Collapse
|
36
|
Essential tremor quantification during activities of daily living. Parkinsonism Relat Disord 2011; 17:537-42. [PMID: 21570891 DOI: 10.1016/j.parkreldis.2011.04.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/07/2011] [Accepted: 04/24/2011] [Indexed: 11/22/2022]
Abstract
BACKGROUND Essential tremor (ET), characterized primarily by postural and kinetic tremor, is typically measured in the clinic with subjective tremor rating scales. These ratings are often used to adjust medications and assess efficacy in clinical trials. However, tremor ratings require the presence of a clinician and do not necessarily capture tremor fluctuations throughout the day during activities of daily living (ADL). OBJECTIVE To evaluate the ability of motion sensors to discriminate tremor from voluntary posture and motion, classify tremor as postural or kinetic, and rate tremor severity during standardized tasks and non-standardized activities of daily living. METHODS Ten subjects with ET wore motion sensors on the index finger and performed standardized motor tasks from the Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET) tremor rating scale (wTRS) and non-standardized ADL tasks. Four movement disorder specialists independently rated video segments of the standardized tasks but not the ADL tasks. Quantitative features were extracted from the motion sensors and used to develop mathematical models for predicting rating scores from kinematic data. RESULTS The quantitative motion features were highly correlated with wTRS ratings for postural (r = 0.90) and kinetic (r = 0.80) tremors. Mathematical models produced tremor ratings that correlated strongly with clinician ratings of the wTRS tasks (mean r = 0.80) and also produced ADL task ratings that correlated well with the most recent clinician wTRS ratings (mean r = 0.72). CONCLUSIONS Recordings from motion sensors can be used to classify tremor as postural or kinetic and quantify tremor severity during both standardized and non-standardized activities.
Collapse
|
37
|
Uhríková Z, Šprdlík O, Hoskovcová M, Komárek A, Ulmanová O, Hlaváč V, Nugent CD, Růžička E. Validation of a new tool for automatic assessment of tremor frequency from video recordings. J Neurosci Methods 2011; 198:110-3. [DOI: 10.1016/j.jneumeth.2011.02.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 02/25/2011] [Accepted: 02/28/2011] [Indexed: 11/29/2022]
|
38
|
Abstract
Essential tremor (ET) is among the most common neurological disorders. This chapter reviews the epidemiology, clinical features, and pathophysiology of ET. The defining feature is a kinetic tremor of the arms. Patients often have a postural tremor as well. Other body regions may also be involved (especially the head). The severity of tremor may range from mild cases in population settings to more severe cases in treatment settings. Motor features aside from tremor have been described in ET, including tandem gait difficulty. Mild cognitive changes (especially executive dysfunction) have been documented in many studies as well. Despite being regarded as one of the most common hyperkinetic movement disorders, establishing a precise prevalence has been difficult, yet the prevalence among persons aged 40 and older seems to be 4% or higher. There are numerous examples of families in which the disease appears to be inherited yet genetic studies have not progressed to the point where ET genes have been identified. There is also a growing understanding that environmental factors are likely to contribute to the etiology of ET. More recent postmortem studies have helped localize the possible source of ET to structural alterations in the cerebellum and its connecting pathways.
Collapse
|
39
|
|
40
|
Héroux ME, Pari G, Norman KE. The effect of contraction intensity on force fluctuations and motor unit entrainment in individuals with essential tremor. Clin Neurophysiol 2009; 121:233-9. [PMID: 20045376 DOI: 10.1016/j.clinph.2009.10.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Revised: 10/28/2009] [Accepted: 10/28/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Quantify the effect of increasing contraction intensity on the amplitude of force fluctuations and neuromuscular and force tremor spectral power. METHODS Twenty-one subjects with essential tremor (ET) and 22 healthy controls applied isometric wrist extension contractions. Various sub-maximal contraction intensities were evaluated (5%-, 10%-, 20%- and 30%-MVC). Force fluctuations and wrist extensor neuromuscular activity were recorded using a load cell and electromyography (EMG). RESULTS Higher contraction intensities were associated with larger amplitude force fluctuations and greater neuromuscular activation. However, spectral power associated with tremor peaks remained relatively constant (EMG) or decreased (force) with increasing contraction intensity. CONCLUSIONS Motor unit entrainment associated with centrally generated oscillatory inputs does not increase with greater levels of muscle activation. SIGNIFICANCE Rather than influencing a constant proportion of active motor units, abnormal oscillatory drive influences a relative constant number of total motor units. When combined with the findings from our previous study on postural tremor, the present results provide preliminary evidence that abnormal stretch reflex activity may contribute to this motor unit entrainment.
Collapse
Affiliation(s)
- M E Héroux
- School of Human Kinetic, University of British Columbia, 210 - 6081 University Boulevard, BC, Canada.
| | | | | |
Collapse
|
41
|
Héroux M, Pari G, Norman K. The effect of inertial loading on wrist postural tremor in essential tremor. Clin Neurophysiol 2009; 120:1020-9. [DOI: 10.1016/j.clinph.2009.03.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Revised: 03/18/2009] [Accepted: 03/21/2009] [Indexed: 11/30/2022]
|
42
|
Papapetropoulos S, Gallo BV, Guevara A, Singer C, Mitsi G, Lyssikatos C, Jagid JR. Objective tremor registration during DBS surgery for essential tremor. Clin Neurol Neurosurg 2009; 111:376-9. [PMID: 19121890 DOI: 10.1016/j.clineuro.2008.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 10/19/2008] [Accepted: 10/31/2008] [Indexed: 10/21/2022]
Abstract
Essential Tremor (ET) is characterized by a 4-12-Hz postural and kinetic tremor, most commonly affecting the upper limbs. Deep brain stimulation (DBS) of the thalamus (Vim) has been found to be highly effective in severe/refractory forms of ET. Intra-operative assessment of tremor is performed using clinical methods based on patient and physician perception of tremor intensity. We present for the first time the case of a patient whose tremor was objectively monitored/quantified pre- and intra-operatively using device-based tremor registration to supplement clinical measures. We present the case of a 76-year-old right-handed woman that received unilateral (left-sided) DBS of the ventrointermediate (Vim) nucleus of thalamus (Vim) for medically refractory ET. Tremor was monitored with an accelerometer-based Tremor Pen, which is part of a simple portable device (CATSYS 2000 System, Danish Product Development Ltd., DK, www.catsys.dk). The patient was asked to perform tasks for tremor evaluation before and during thalamic DBS. Tremor quantification revealed a significant improvement (34.7-fold) in the contralateral (right) limb following macro-stimulation. No significant improvement was registered in the ipsilateral (non-operated) side. Simple electronic tremor registration methods during DBS of the Vim nucleus of the thalamus may supplement the existing methodology that is solely based on subjective measures derived from clinical observations.
Collapse
Affiliation(s)
- Spiridon Papapetropoulos
- Division of Movement Disorders, Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, United States.
| | | | | | | | | | | | | |
Collapse
|
43
|
Hellwig B, Mund P, Schelter B, Guschlbauer B, Timmer J, Lücking CH. A longitudinal study of tremor frequencies in Parkinson's disease and essential tremor. Clin Neurophysiol 2008; 120:431-5. [PMID: 19101200 DOI: 10.1016/j.clinph.2008.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Revised: 09/14/2008] [Accepted: 11/04/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVE There is evidence that the tremor frequency in essential tremor (ET) decreases with time. Longitudinal studies on the evolution of tremor frequencies in Parkinson's disease (PD) have so far not been published. Here, we present a longitudinal analysis of tremor frequencies in PD and ET. METHODS We analyzed the standardized accelerometric and electromyographic tremor recordings of 53 patients with PD and 38 patients with ET who underwent repeated routine tremor recordings between 1991 and 2002. RESULTS In an average follow-up period of 44.9 months in PD and 50.6 months in ET, the average number of tremor recordings was 3.3 in PD and 3.7 in ET. In both disorders, tremor frequencies tended to decrease with time. The average annual decrease of the tremor frequency was 0.09 Hz/year in Parkinsonian rest tremor, 0.08 Hz/year in Parkinsonian postural tremor and 0.12 Hz/year in ET. CONCLUSIONS The tremor frequency decreases with time in both PD and ET. The similarity of this decrease in PD and ET may point to a common underlying pathophysiological mechanism. SIGNIFICANCE Decreasing tremor frequencies with time may be functionally important by inducing larger tremor amplitudes due to the low-pass filtering properties of muscles and limbs.
Collapse
Affiliation(s)
- B Hellwig
- Neurologische Universitätsklinik, Neurozentrum, Breisacher Strasse 64, 79106 Freiburg, Germany.
| | | | | | | | | | | |
Collapse
|
44
|
|
45
|
Farkas Z, Csillik A, Szirmai I, Kamondi A. Asymmetry of tremor intensity and frequency in Parkinson's disease and essential tremor. Parkinsonism Relat Disord 2005; 12:49-55. [PMID: 16271493 DOI: 10.1016/j.parkreldis.2005.07.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 06/28/2005] [Accepted: 07/25/2005] [Indexed: 11/17/2022]
Abstract
We investigated the asymmetry of tremor intensity, frequency and frequency dispersion of Parkinsonian (PT) and essential (ET) tremor using accelerometry. Data of the more and less trembling hands were statistically elaborated. We found that tremor intensity was significantly asymmetric not only in PT but also in ET, while frequency and frequency dispersion were symmetric in ET but asymmetric in PT. We conclude that bilateral assessment of frequency related tremor parameters may be used for differentiation between ET and PT, and provides further details on the central organization of tremor generators.
Collapse
Affiliation(s)
- Zsuzsanna Farkas
- Department of Neurology, Semmelweis University, Balassa u. 6., 1083 Budapest, Hungary
| | | | | | | |
Collapse
|
46
|
Elble RJ, Higgins C, Elble S. Electrophysiologic transition from physiologic tremor to essential tremor. Mov Disord 2005; 20:1038-42. [PMID: 15852370 DOI: 10.1002/mds.20487] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We electrophysiologically examined the transition from physiologic tremor to essential tremor in people at risk for familial essential tremor. Two healthy people from different families with hereditary essential tremor were studied on multiple occasions. A 23-year-old man was studied in 1995, 1997, and 2004, and a 44-year-old woman was studied in 1993, 1995, 1997, and 2003. Hand acceleration and forearm electromyographic readings were measured with and without 300-g loading to determine the characteristic frequency-invariant motor unit entrainment of essential tremor. Clinically and electrophysiologically, the man and woman had normal tremor until the last examination, when both exhibited a fine tremulousness in the outstretched hands and frequency-invariant motor unit entrainment at 7.5 and 6.5 Hz, respectively. At no time did either patient exhibit a prominent 8-12 Hz component of physiologic tremor. Essential tremor in young adults may begin at frequencies less than 8-12 Hz, and this electrophysiologic abnormality is detectable when clinical examinations reveal only questionably abnormal tremor. More young adults at risk for essential tremor must be studied to determine whether initial frequencies less than 8 Hz are the rule or the exception. Nevertheless, the data from our 2 patients demonstrate that a prominent 8-12 Hz component of physiologic tremor does not always precede the development of essential tremor; therefore, the origins of essential tremor and the 8-12 Hz component of physiologic tremor may be different.
Collapse
Affiliation(s)
- Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 92794-9643, USA.
| | | | | |
Collapse
|
47
|
Legros A, Diakonova N, Cif L, Hemm S, Vayssière N, Coubes P, Beuter A. Accelerometric measurement of involuntary movements during pallidal deep brain stimulation of patients with generalized dystonia. Brain Res Bull 2004; 64:363-9. [PMID: 15561472 DOI: 10.1016/j.brainresbull.2004.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2003] [Accepted: 09/13/2004] [Indexed: 10/26/2022]
Abstract
Accelerometric activity during rest and posture was quantified in the upper dominant limb of 14 patients with primary or secondary dystonia and five healthy control subjects. Data were recorded before and after bilateral implantation of the stimulating electrodes in the Globus Pallidus internus. Clinical evaluation was based on the Burke-Marsden-Fahn's Dystonia Rating Scale (BMFDRS). For the patient group, I(t), the integral (i.e. area) of the acceleration power spectrum over the total frequency range (0.6-16 Hz) decreased as the clinical state of the patients improved following deep brain stimulation (p < 0.01) during rest and posture. Ten days after surgery, there were no I(t) differences between control subjects and patients (p > 0.05). A significant correlation was found between the global BMFDRS scores and I(t) for rest (p < 0.01) but not for posture. No significant correlation was found between I(t) and a partial BMFDRS score for the right arm for rest or posture. The integral I(t) provides a valid indicator of the motor activity generated by the arm of the patient but further analyses are needed to monitor patients' progress not only during their hospitalization but also after they are released from the hospital, and to understand why this measure does not correlate with partial BMFDRS scores.
Collapse
Affiliation(s)
- A Legros
- Efficience et Déficience Motrice (EA 2991) and Department of Pediatric Neurosurgery (Research Unit on Movement Disorders in Children), University Hospital Gui de Chauliac, Montpellier, France
| | | | | | | | | | | | | |
Collapse
|
48
|
Gao JB. Analysis of amplitude and frequency variations of essential and Parkinsonian tremors. Med Biol Eng Comput 2004; 42:345-9. [PMID: 15191080 DOI: 10.1007/bf02344710] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Variations in the amplitude and period of essential and Parkinsonian tremors were studied. It was found that the variations in frequency (or period) were mostly similar to the white noise, with the standard deviation typically less than 10% of the mean, whereas the variations in amplitude were much larger, with standard deviations greater than 30% of the mean, and so could not be effectively smoothed by running means. It is conjectured that variations in frequency reflect the stable nature of the neural network that generates the rhythmicity responsible for the tremor. The variations in amplitude, however, reflect more the fluctuations in the firing of individual neurons in the network. It is further discussed that the oscillator behind pathological tremor has a stochastic nature and can be characterised as a diffusional process. The latter suggests that it is sometimes possible for tremors to be described as chaotic processes on certain scales in phase space. It is further discussed how the stochastic nature of tremors determines the lack of correlation between different tremulous parts of the body.
Collapse
Affiliation(s)
- J B Gao
- Department of Electrical & Computer Engineering, University of Florida, USA.
| |
Collapse
|
49
|
|
50
|
Zeuner KE, Molloy FM, Shoge RO, Goldstein SR, Wesley R, Hallett M. Effect of ethanol on the central oscillator in essential tremor. Mov Disord 2003; 18:1280-5. [PMID: 14639668 DOI: 10.1002/mds.10553] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We investigated the effects of ethanol and diazepam on the central, mechanical, and mechanical reflex components of tremor in patients with essential tremor (ET). A double-blind crossover study (ethanol or diazepam) was conducted on 2 separate days. Dose of ethanol or diazepam was calculated in each individual according to height, weight, and age in 10 patients with ET. The postural tremor amplitude at the wrist was recorded using a three-dimensional accelerometer placed on the dorsum of the hand. Electromyogram (EMG) was recorded with surface electrodes placed on the forearm extensors and flexors. To separate central and mechanical (reflex) components, a 500-g weight was placed on the dorsum of the hand during a second tremor measurement. Tremor recordings were done at baseline and 30, 60, 90, and 120 minutes after drug ingestion. Ethanol and diazepam blood levels were measured at baseline and after 20, 40, 80, and 120 minutes. Blood ethanol and diazepam levels were highest after 40 and 80 minutes. The amplitude of the central component 60 minutes after ingestion of ethanol was decreased significantly (P = 0.029) compared with diazepam. Our findings suggest that the improvement in tremor after ethanol ingestion was due, at least in part, to an effect on a central oscillator.
Collapse
Affiliation(s)
- Kirsten E Zeuner
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-1428, USA
| | | | | | | | | | | |
Collapse
|