Skip Navigation
Skip to contents

JMD : Journal of Movement Disorders

OPEN ACCESS
SEARCH
Search

Most cited

Page Path
HOME > Browse Articles > Most cited
71 Most cited
Filter
Filter
Article category
Keywords
Publication year
Authors
Funded articles

From articles published in Journal of Movement Disorders during the past two years (2020 ~ ).

Review Articles
COVID-19: An Early Review of Its Global Impact and Considerations for Parkinson’s Disease Patient Care
Roongroj Bhidayasiri, Sasivimol Virameteekul, Jong-Min Kim, Pramod Kr. Pal, Sun-Ju Chung
J Mov Disord. 2020;13(2):105-114.   Published online April 30, 2020
DOI: https://doi.org/10.14802/jmd.20042
  • 11,883 View
  • 728 Download
  • 41 Citations
AbstractAbstract PDF
While many infectious disorders are unknown to most neurologists, COVID-19 is very different. It has impacted neurologists and other health care workers, not only in our professional lives but also through the fear and panic within our own families, colleagues, patients and their families, and even in the wider public. COVID-19 affects all sorts of individuals, but the elderly with underlying chronic conditions are particularly at risk of severe disease, or even death. Parkinson’s disease (PD) shares a common profile as an age-dependent degenerative disorder, frequently associated with comorbidities, particularly cardiovascular diseases, so PD patients will almost certainly fall into the high-risk group. Therefore, the aim of this review is to explore the risk of COVID-19 in PD based on the susceptibility to severe disease, its impact on PD disease severity, potential long-term sequelae, and difficulties of PD management during this outbreak, where neurologists face various challenges on how we can maintain effective care for PD patients without exposing them, or ourselves, to the risk of infection. It is less than six months since the identification of the original COVID-19 case on New Year’s Eve 2019, so it is still too early to fully understand the natural history of COVID-19 and the evidence on COVID-19-related PD is scant. Though the possibilities presented are speculative, they are theory-based, and supported by prior evidence from other neurotrophic viruses closely related to SARS-CoV-2. Neurologists should be on high alert and vigilant for potential acute and chronic complications when encountering PD patients who are suspected of having COVID-19.
Update on Current Technologies for Deep Brain Stimulation in Parkinson’s Disease
Michelle Paff, Aaron Loh, Can Sarica, Andres M. Lozano, Alfonso Fasano
J Mov Disord. 2020;13(3):185-198.   Published online August 31, 2020
DOI: https://doi.org/10.14802/jmd.20052
  • 11,989 View
  • 546 Download
  • 30 Citations
AbstractAbstract PDF
Deep brain stimulation (DBS) is becoming increasingly central in the treatment of patients with Parkinson’s disease and other movement disorders. Recent developments in DBS lead and implantable pulse generator design provide increased flexibility for programming, potentially improving the therapeutic benefit of stimulation. Directional DBS leads may increase the therapeutic window of stimulation by providing a means of avoiding current spread to structures that might give rise to stimulation-related side effects. Similarly, control of current to individual contacts on a DBS lead allows for shaping of the electric field produced between multiple active contacts. The following review aims to describe the recent developments in DBS system technology and the features of each commercially available DBS system. The advantages of each system are reviewed, and general considerations for choosing the most appropriate system are discussed.
Principles of Electrophysiological Assessments for Movement Disorders
Kai-Hsiang Stanley Chen, Robert Chen
J Mov Disord. 2020;13(1):27-38.   Published online January 31, 2020
DOI: https://doi.org/10.14802/jmd.19064
  • 9,273 View
  • 823 Download
  • 21 Citations
AbstractAbstract PDFSupplementary Material
Electrophysiological studies can provide objective and quantifiable assessments of movement disorders. They are useful in the diagnosis of hyperkinetic movement disorders, particularly tremors and myoclonus. The most commonly used measures are surface electromyography (sEMG), electroencephalography (EEG) and accelerometry. Frequency and coherence analyses of sEMG signals may reveal the nature of tremors and the source of the tremors. The effects of voluntary tapping, ballistic movements and weighting of the limbs can help to distinguish between organic and functional tremors. The presence of Bereitschafts-potentials and beta-band desynchronization recorded by EEG before movement onset provide strong evidence for functional movement disorders. EMG burst durations, distributions and muscle recruitment orders may identify and classify myoclonus to cortical, subcortical or spinal origins and help in the diagnosis of functional myoclonus. Organic and functional cervical dystonia can potentially be distinguished by EMG power spectral analysis. Several reflex circuits, such as the long latency reflex, blink reflex and startle reflex, can be elicited with different types of external stimuli and are useful in the assessment of myoclonus, excessive startle and stiff person syndrome. However, limitations of the tests should be recognized, and the results should be interpreted together with clinical observations.
Immune-Mediated Cerebellar Ataxias: Clinical Diagnosis and Treatment Based on Immunological and Physiological Mechanisms
Hiroshi Mitoma, Mario Manto, Marios Hadjivassiliou
J Mov Disord. 2021;14(1):10-28.   Published online January 12, 2021
DOI: https://doi.org/10.14802/jmd.20040
  • 6,375 View
  • 493 Download
  • 15 Citations
AbstractAbstract PDF
Since the first description of immune-mediated cerebellar ataxias (IMCAs) by Charcot in 1868, several milestones have been reached in our understanding of this group of neurological disorders. IMCAs have diverse etiologies, such as gluten ataxia, postinfectious cerebellitis, paraneoplastic cerebellar degeneration, opsoclonus myoclonus syndrome, anti-GAD ataxia, and primary autoimmune cerebellar ataxia. The cerebellum, a vulnerable autoimmune target of the nervous system, has remarkable capacities (collectively known as the cerebellar reserve, closely linked to plasticity) to compensate and restore function following various pathological insults. Therefore, good prognosis is expected when immune-mediated therapeutic interventions are delivered during early stages when the cerebellar reserve can be preserved. However, some types of IMCAs show poor responses to immunotherapies, even if such therapies are introduced at an early stage. Thus, further research is needed to enhance our understanding of the autoimmune mechanisms underlying IMCAs, as such research could potentially lead to the development of more effective immunotherapies. We underscore the need to pursue the identification of robust biomarkers.
Diagnostic Criteria for Dementia with Lewy Bodies: Updates and Future Directions
Masahito Yamada, Junji Komatsu, Keiko Nakamura, Kenji Sakai, Miharu Samuraki-Yokohama, Kenichi Nakajima, Mitsuhiro Yoshita
J Mov Disord. 2020;13(1):1-10.   Published online November 8, 2019
DOI: https://doi.org/10.14802/jmd.19052
  • 19,800 View
  • 1,432 Download
  • 15 Citations
AbstractAbstract PDF
The aim of this article is to describe the 2017 revised consensus criteria for the clinical diagnosis of dementia with Lewy bodies (DLB) with future directions for the diagnostic criteria. The criteria for the clinical diagnosis of probable and possible DLB were first published as the first consensus report in 1996 and were revised in the third consensus report in 2005. After discussion at the International DLB Conference in Fort Lauderdale, Florida, USA, in 2015, the International DLB Consortium published the fourth consensus report including the revised consensus criteria in 2017. The 2017 revised criteria clearly distinguish between clinical features and diagnostic biomarkers. Significant new information about previously reported aspects of DLB has been incorporated, with increased diagnostic weighting given to rapid eye movement (REM) sleep behavior disorder (RBD) and iodine-123-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. Future directions include the development of the criteria for early diagnosis (prodromal DLB) and the establishment of new biomarkers that directly indicate Lewy-related pathology, including α-synuclein imaging, biopsies of peripheral tissues (skin, etc.) for the demonstration of α-synuclein deposition, and biochemical markers (cerebrospinal fluid/blood), as well as the pathological evaluation of the sensitivity and specificity of the 2017 revised diagnostic criteria. In conclusion, the revised consensus criteria for the clinical diagnosis of DLB were reported with the incorporation of new information about DLB in 2017. Future directions include the development of the criteria for early diagnosis and the establishment of biomarkers directly indicative of Lewy-related pathology.
Original Article
Health-Related Quality of Life for Parkinson’s Disease Patients and Their Caregivers
Michal Lubomski, Ryan L. Davis, Carolyn M. Sue
J Mov Disord. 2021;14(1):42-52.   Published online January 12, 2021
DOI: https://doi.org/10.14802/jmd.20079
  • 5,237 View
  • 181 Download
  • 12 Citations
AbstractAbstract PDF
Objective
Motor and non-motor symptoms (NMS) negatively impact the health-related quality of life (HRQoL) for individuals with Parkinson’s disease (PD), as well as their caregivers. NMS can emerge decades prior to the manifestation of motor symptoms but often go unrecognized and therefore untreated. To guide clinical management, we surveyed differences and identified factors that influence HRQoL in a cohort of PD patients and family caregivers.
Methods
A total of 103 PD patients were compared with 81 caregivers. Outcome measures collected from validated questionnaires included generic and disease-specific HRQoL assessments, depression frequency and severity, constipation severity, upper and lower gastrointestinal symptoms, physical activity and motor symptom severity.
Results
PD patients reported significantly decreased physical and mental HRQoL compared to their caregivers (both p < 0.001). Unemployment, the need for social support services, rehabilitation use, REM sleep behavior disorder, impulse control disorders and features suggestive of increasing disease severity hallmarked by increasing PD duration, higher MDS UPDRS-III (Movement Disorder Society–Unified Parkinson’s Disease Rating Scale–Part III) scores, higher daily levodopa equivalence dose and motor fluctuations were consistent with a lower HRQoL in our PD cohort. Furthermore, decreased physical activity, chronic pain, depression, constipation and upper gastrointestinal dysfunction (particularly indigestion, excess fullness and bloating) suggested vulnerability to reduced HRQoL. Overall, PD patients perceived their health to decline by 12% more than their caregivers did over a 1-year period.
Conclusion
PD patients reported decreased HRQoL, with both motor symptoms and NMS negatively impacting HRQoL. Our findings support the routine clinical screening of HRQoL in PD patients to identify and address modifiable factors.
Review Article
Immunotherapy Targeting Neurodegenerative Proteinopathies: α-Synucleinopathies and Tauopathies
Junghwan Shin, Han-Joon Kim, Beomseok Jeon
J Mov Disord. 2020;13(1):11-19.   Published online December 19, 2019
DOI: https://doi.org/10.14802/jmd.19057
  • 6,120 View
  • 381 Download
  • 12 Citations
AbstractAbstract PDF
α-Synuclein and tau deposition in the central nervous system is responsible for various parkinsonian syndromes, including Parkinson’s disease, multiple system atrophy, dementia with Lewy bodies, progressive supranuclear palsy and corticobasal degeneration. Emerging evidence has suggested that pathologic α-synuclein and tau are transmitted from cell to cell and further accelerate the aggregation of pathologic proteins in neighboring cells. Furthermore, extracellular pathologic proteins have also been reported to provoke inflammatory responses that lead to neurodegeneration. Therefore, immunotherapies targeting extracellular α-synuclein and tau have been proposed as potential disease-modifying strategies. In this review, we summarize completed phase I trials and ongoing phase II trials of immunotherapies against α-synuclein and tau and further discuss concerns and hurdles to overcome in the future.
Original Article
Association between Olfactory Deficit and Motor and Cognitive Function in Parkinson’s Disease
Han Soo Yoo, Seok Jong Chung, Yang Hyun Lee, Byoung Seok Ye, Young H. Sohn, Phil Hyu Lee
J Mov Disord. 2020;13(2):133-141.   Published online April 6, 2020
DOI: https://doi.org/10.14802/jmd.19082
  • 5,997 View
  • 235 Download
  • 11 Citations
AbstractAbstract PDFSupplementary Material
Objective
To investigate whether baseline olfactory dysfunction in Parkinson’s disease (PD) patients is associated with baseline and longitudinal motor and cognitive function.
Methods
We recruited 228 drug-naïve PD patients who were followed for a mean of 6 years. Patients underwent the Cross-Cultural Smell Identification Test (CCSIT), a neuropsychological test, and N-(3-[18F]fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane positron emission tomography within 6 months of the baseline evaluation. Olfactory dysfunction was categorized as normosmia (CCSIT score ≥ 9), hyposmia (CCSIT score 5–8), and anosmia (CCSIT score ≤ 4). During the follow-up period, we investigated changes in the levodopa-equivalent dose (LED) and the occurrence of wearing-off, levodopa-induced dyskinesia, and dementia.
Results
Among the PD patients, 80.7% were hyposmic at the time of diagnosis, and 26.1% were anosmic. Baseline olfactory dysfunction was not associated with either initial parkinsonian motor symptoms or with the longitudinal LED increment and motor complications. Meanwhile, the anosmic group had lower baseline scores on the Korea version of the Boston Naming Test and Stroop color reading test than the normosmic and hyposmic groups. The anosmic group exhibited a higher rate of conversion to dementia than the normosmic [adjusted hazard ratio (HR) 3.99, 95% confidence interval (CI) 1.08–14.72] and hyposmic (adjusted HR 2.48, 95% CI 1.15–5.32) PD groups, regardless of baseline motor deficits and cognitive status.
Conclusion
Baseline olfactory dysfunction was not associated with motor deficits and complications, but it was associated with cognitive dysfunction and prognosis, suggesting that severe olfactory impairment may reflect early cortical involvement, probably in the frontotemporal region, and rapid spreading of Lewy body pathology.
Review Articles
Progressive Supranuclear Palsy with Predominant Cerebellar Ataxia
Shoichiro Ando, Masato Kanazawa, Osamu Onodera
J Mov Disord. 2020;13(1):20-26.   Published online December 19, 2019
DOI: https://doi.org/10.14802/jmd.19061
  • 6,283 View
  • 337 Download
  • 11 Citations
AbstractAbstract PDF
Progressive supranuclear palsy (PSP) is characterized by supranuclear gaze palsy, dystonic rigidity of the neck and upper trunk, frequent falls and mild cognitive impairment. Cerebellar ataxia is one of the exclusion criteria given by the National Institute of Neurological Disorders and Stroke and the Society for Progressive Supranuclear Palsy. As a result, pathologically proven PSP patients exhibiting cerebellar ataxia have often been misdiagnosed with spinocerebellar degeneration, specifically multiple system atrophy with predominant cerebellar ataxia (MSA-C). However, more recently, it has been recognized that patients with PSP can present with truncal and limb ataxia as their initial symptom and/or main manifestation. These patients can be classified as having PSP with predominant cerebellar ataxia (PSP-C), a new subtype of PSP. Since the development of this classification, patients with PSP-C have been identified primarily in Asian countries, and it has been noted that this condition is very rare in Western communities. Furthermore, the clinical features of PSP-C have been identified, enabling it to be distinguished from other subtypes of PSP and MSA-C. In this review, we describe the clinical and neuropathological features of PSP-C. The hypothesized pathophysiology of cerebellar ataxia in PSP-C is also discussed.
Emerging Concepts of Motor Reserve in Parkinson’s Disease
Seok Jong Chung, Jae Jung Lee, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2020;13(3):171-184.   Published online August 31, 2020
DOI: https://doi.org/10.14802/jmd.20029
  • 6,491 View
  • 257 Download
  • 10 Citations
AbstractAbstract PDF
The concept of cognitive reserve (CR) in Alzheimer’s disease (AD) explains the differences between individuals in their susceptibility to AD-related pathologies. An enhanced CR may lead to less cognitive deficits despite severe pathological lesions. Parkinson’s disease (PD) is also a common neurodegenerative disease and is mainly characterized by motor dysfunction related to striatal dopaminergic depletion. The degree of motor deficits in PD is closely correlated to the degree of dopamine depletion; however, significant individual variations still exist. Therefore, we hypothesized that the presence of motor reserve (MR) in PD explains the individual differences in motor deficits despite similar levels of striatal dopamine depletion. Since 2015, we have performed a series of studies investigating MR in de novo patients with PD using the data of initial clinical presentation and dopamine transporter PET scan. In this review, we summarized the results of these published studies. In particular, some premorbid experiences (i.e., physical activity and education) and modifiable factors (i.e., body mass index and white matter hyperintensity on brain image studies) could modulate an individual’s capacity to tolerate PD pathology, which can be maintained throughout disease progression.
Original Article
Automated Brainstem Segmentation Detects Differential Involvement in Atypical Parkinsonian Syndromes
Martina Bocchetta, Juan Eugenio Iglesias, Viorica Chelban, Edwin Jabbari, Ruth Lamb, Lucy L. Russell, Caroline V. Greaves, Mollie Neason, David M. Cash, David L. Thomas, Jason D. Warren, John Woodside, Henry Houlden, Huw R. Morris, Jonathan D. Rohrer
J Mov Disord. 2020;13(1):39-46.   Published online September 26, 2019
DOI: https://doi.org/10.14802/jmd.19030
  • 4,509 View
  • 204 Download
  • 9 Citations
AbstractAbstract PDFSupplementary Material
Objective
Brainstem segmentation has been useful in identifying potential imaging biomarkers for diagnosis and progression in atypical parkinsonian syndromes (APS). However, the majority of work has been performed using manual segmentation, which is time consuming for large cohorts.
Methods
We investigated brainstem involvement in APS using an automated method. We measured the volume of the medulla, pons, superior cerebellar peduncle (SCP) and midbrain from T1-weighted MRIs in 67 patients and 42 controls. Diagnoses were corticobasal syndrome (CBS, n = 14), multiple system atrophy (MSA, n = 16: 8 with parkinsonian syndrome, MSA-P; 8 with cerebellar syndrome, MSA-C), progressive supranuclear palsy with a Richardson’s syndrome (PSP-RS, n = 12), variant PSP (n = 18), and APS not otherwise specified (APS-NOS, n = 7).
Results
All brainstem regions were smaller in MSA-C (19–42% volume difference, p < 0.0005) and in both PSP groups (18–33%, p < 0.0005) than in controls. MSA-P showed lower volumes in all regions except the SCP (15–26%, p < 0.0005). The most affected region in MSA-C and MSA-P was the pons (42% and 26%, respectively), while the most affected regions in both the PSP-RS and variant PSP groups were the SCP (33% and 23%, respectively) and midbrain (26% and 24%, respectively). The brainstem was less affected in CBS, but nonetheless, the pons (14%, p < 0.0005), midbrain (14%, p < 0.0005) and medulla (10%, p = 0.001) were significantly smaller in CBS than in controls. The brainstem was unaffected in APS-NOS.
Conclusion
Automated methods can accurately quantify the involvement of brainstem structures in APS. This will be important in future trials with large patient numbers where manual segmentation is unfeasible.
Review Article
Manganese and Movement Disorders: A Review
Dinkar Kulshreshtha, Jacky Ganguly, Mandar Jog
J Mov Disord. 2021;14(2):93-102.   Published online April 6, 2021
DOI: https://doi.org/10.14802/jmd.20123
  • 4,876 View
  • 320 Download
  • 8 Citations
AbstractAbstract PDF
Scientific and technological advances achieved with industrial expansion have led to an ever-increasing demand for heavy metals. This demand has, in turn, led to increased contamination of soil, water and air with these metals. Chronic exposure to metals may be detrimental not only to occupational workers but also to the nonoccupational population exposed to these metals. Manganese (Mn), a commonly used heavy metal, is an essential cofactor for many enzymatic processes that drive biological functions. However, it is also a potential source of neurotoxicity, particularly in the field of movement disorders. The typical manifestation of Mn overexposure is parkinsonism, which may be difficult to differentiate from the more common idiopathic Parkinson’s disease. In addition to environmental exposure to Mn, other potential etiologies causing hypermanganesemia include systemic health conditions, total parenteral nutrition and genetic mutations causing Mn dyshomeostasis. In this review, we critically analyze Mn and discuss its sources of exposure, pathophysiology and clinical manifestations. We have highlighted the global public health impact of Mn and emphasize that movement disorder specialists should record a detailed social and occupational history to ensure that a toxic etiology is not misdiagnosed as a neurodegenerative disease. In the absence of a definite therapeutic option, early diagnosis and timely institution of preventive measures are the keys to managing its toxic effects.
Case Report
Successful Pallidal Stimulation in a Patient with KMT2B-Related Dystonia
Jun Kyu Mun, Ah Reum Kim, Jong Hyeon Ahn, Minkyeong Kim, Jin Whan Cho, Jung-Il Lee, Kyung Rae Cho, Jinyoung Youn
J Mov Disord. 2020;13(2):154-158.   Published online April 6, 2020
DOI: https://doi.org/10.14802/jmd.19087
  • 4,595 View
  • 146 Download
  • 8 Citations
AbstractAbstract PDFSupplementary Material
Although the KMT2B gene was identified as a causative gene for early-onset generalized dystonia, the efficacy of deep brain stimulation (DBS) in KMT2B-related dystonia has not been clearly elucidated. Here, we describe a 28-year-old woman who developed generalized dystonia with developmental delay, microcephaly, short stature, and cognitive decline. She was diagnosed with KMT2B- related dystonia using whole-exome sequencing with a heterozygous frameshift insertion of c.515dupC (p.T172fs) in the KMT2B gene. Oral medications and botulinum toxin injection were not effective. The dystonia markedly improved with bilateral pallidal DBS (the Burke-Fahn-Marsden Dystonia Rating Scale score was reduced from 30 to 5 on the dystonia movement scale and from 11 to 1 on the disability scale), and she could walk independently. From this case, we suggest that bilateral globus pallidus internus DBS can be an effective treatment option for patients with KMT2B-related generalized dystonia.
Original Articles
The Non-Motor Symptom Profile of Progressive Supranuclear Palsy
Sudhakar Pushpa Chaithra, Shweta Prasad, Vikram Venkappayya Holla, Albert Stezin, Nitish Kamble, Ravi Yadav, Pramod Kumar Pal
J Mov Disord. 2020;13(2):118-126.   Published online April 6, 2020
DOI: https://doi.org/10.14802/jmd.19066
  • 5,006 View
  • 219 Download
  • 7 Citations
AbstractAbstract PDF
Objective
Non-motor symptoms (NMSs) significantly contribute to increased morbidity and poor quality of life in patients with parkinsonian disorders. This study aims to explore the profile of NMSs in patients with progressive supranuclear palsy (PSP) using the validated Non-Motor Symptom Scale (NMSS).
Methods
Seventy-six patients with PSP were evaluated in this study. Motor symptoms and NMSs were evaluated using the PSP Rating Scale (PSPRS), Unified Parkinson’s Disease Rating Scale-III, Montreal Cognitive Assessment, Hamilton Depression (HAMD) and Anxiety Rating Scales, Parkinson’s Disease Sleep Scale (PDSS) and NMSS. NMS severity and prevalence were also compared between patients with PSP-Richardson syndrome (PSP-RS) and those with PSP-parkinsonism.
Results
All subjects in this cohort reported at least 2 NMSs. The most prevalent NMSs in patients with PSP were in the domains of sleep/fatigue, mood/cognition, and sexual function. The least prevalent NMSs were in the domains of cardiovascular including falls, and perceptual problems/hallucinations. Significant correlations were observed between the NMSS scores and HAM-D, PDSS, PSPRS scores and PSPRS sub-scores. The severity of NMSs was unrelated to the duration of illness. Patients with PSP-RS reported a higher severity of drooling, altered smell/taste, depression and altered interest in sex and a higher prevalence of sexual dysfunction.
Conclusion
NMSs are commonly observed in patients with PSP, and the domains of sleep, mood and sexual function are most commonly affected. These symptoms contribute significantly to disease morbidity, and clinicians should pay adequate attention to identifying and addressing these symptoms.
Comparison of Spontaneous Motor Tempo during Finger Tapping, Toe Tapping and Stepping on the Spot in People with and without Parkinson’s Disease
Dawn Rose, Daniel J. Cameron, Peter J. Lovatt, Jessica A. Grahn, Lucy E. Annett
J Mov Disord. 2020;13(1):47-56.   Published online January 31, 2020
DOI: https://doi.org/10.14802/jmd.19043
  • 10,874 View
  • 137 Download
  • 7 Citations
AbstractAbstract PDFSupplementary Material
Objective
Spontaneous motor tempo (SMT), observed in walking, tapping and clapping, tends to occur around 2 Hz. Initiating and controlling movement can be difficult for people with Parkinson’s (PWP), but studies have not identified whether PWP differ from controls in SMT. For community-based interventions, e.g. dancing, it would be helpful to know a baseline SMT to optimize the tempi of cued activities. Therefore, this study compared finger tapping (FT), toe tapping (TT) and stepping ‘on the spot’ (SS) in PWP and two groups of healthy controls [age-matched controls (AMC) and young healthy controls (YHC)], as SMT is known to change with age.
Methods
Participants (PWP; n = 30, AMC; n = 23, YHC; n = 35) were asked to tap or step on the spot at a natural pace for two trials lasting 40 seconds. The central 30 seconds were averaged for analyses using mean inter-onset intervals (IOI) and coefficient of variation (CoV) to measure rate and variability respectively.
Results
PWP had faster SMT than both control groups, depending on the movement modality: FT, F(2, 87) = 7.92, p < 0.01 (PWP faster than YHC); TT, F(2, 87) = 4.89, p = 0.01 (PWP faster than AMC); and SS, F(2, 77) = 3.26, p = 0.04 (PWP faster than AMC). PWP had higher CoV (more variable tapping) than AMC in FT only, F(2, 87) = 4.10, p = 0.02.
Conclusion
This study provides the first direct comparison of SMT between PWP and two control groups for different types of movements. Results suggest SMT is generally faster in PWP than control groups, and more variable when measured with finger tapping compared to stepping on the spot.

JMD : Journal of Movement Disorders