Dutch translation, adaptation and validation of the OT-10 scale for orthostatic tremor

Introduction

There are currently no effective treatments for primary orthostatic tremor (POT). An adequate disease-specific POT severity scale is a prerequisite to conduct clinical trials and monitor disease severity in clinical practice. Recently, the English OT-10 scale has been developed for this purpose. Here we aimed to obtain a scale to measure the severity of POT in Dutch speaking individuals.

Methods

An established translation, adaptation and validation approach was employed to obtain a Dutch version of the OT-10 scale. Validation was performed in a Dutch POT cohort (n = 46).

Results

A Dutch OT-10 scale was obtained which showed good internal consistency (Cronbach's alpha > 0.80), total score test-retest reliability (intraclass correlation coefficient > 0.80), and concurrent validity (Pearson correlation > 0.80). Item-to-total correlation was good (weighted kappa > 0.40) for all items, and item test-retest reliability was good (weighted kappa > 0.40) for eight out of ten items. Overall, the Dutch OT-10 scale demonstrated acceptable validity.

Conclusions

We obtained and validated a Dutch version of the OT-10 scale, capturing POT severity. Next to its use in clinical practice, translation and validation of the OT-10 scale in more languages will help to find evidence-based treatments for POT.

Plantar Grasp sign as a screening tool for Orthostatic Tremor (OT)

Introduction

Orthostatic tremor (OT) is a rare neurological disorder characterized by a sensation of instability while standing. Very few clinical signs have been described for OT to date. Finding other symptoms and signs could prove valuable for this hard-to-recognized disease.

Methods

This protocol is part of the University of Nebraska Medical Center Orthostatic Tremor longitudinal study. It was noted that OT patients flex their toes and sometimes the foot arch while standing (Plantar Grasp). They reported doing this to "grab" the floor and improve stability. This paper analyses the diagnostic test characteristics of the patient-self-reported Plantar Grasp, a new sign in OT.

Results

There were 34 OT patients (88% females), and 20 controls (65% females). Eighty-eight percent of patients with OT reported the plantar grasp sign and none of the controls. The Plantar Grasp Sign was found to be very sensitive (88%), and extremely specific (100%) in our cohort. Non-weighted Negative Likelihood Ratio (NLR) was 0.12. And the 3% prevalence-weighted NLR was so low that the negative post-test probability was close to zero.

Conclusion

Due to its high sensitivity, specificity, and ideal likelihood ratio, we propose that the Plantar Grasp sign could be considered to screen patients with possible OT. Further studies are needed to determine the specificity of this sign in OT versus other balance disorders.

Consensus Paper: Ataxic Gait

The aim of this consensus paper is to discuss the roles of the cerebellum in human gait, as well as its assessment and therapy. Cerebellar vermis is critical for postural control. The cerebellum ensures the mapping of sensory information into temporally relevant motor commands. Mental imagery of gait involves intrinsically connected fronto-parietal networks comprising the cerebellum. Muscular activities in cerebellar patients show impaired timing of discharges, affecting the patterning of the synergies subserving locomotion. Ataxia of stance/gait is amongst the first cerebellar deficits in cerebellar disorders such as degenerative ataxias and is a disabling symptom with a high risk of falls. Prolonged discharges and increased muscle coactivation may be related to compensatory mechanisms and enhanced body sway, respectively. Essential tremor is frequently associated with mild gait ataxia. There is growing evidence for an important role of the cerebellar cortex in the pathogenesis of essential tremor. In multiple sclerosis, balance and gait are affected due to cerebellar and spinal cord involvement, as a result of disseminated demyelination and neurodegeneration impairing proprioception. In orthostatic tremor, patients often show mild-to-moderate limb and gait ataxia. The tremor generator is likely located in the posterior fossa. Tandem gait is impaired in the early stages of cerebellar disorders and may be particularly useful in the evaluation of pre-ataxic stages of progressive ataxias. Impaired inter-joint coordination and enhanced variability of gait temporal and kinetic parameters can be grasped by wearable devices such as accelerometers. Kinect is a promising low cost technology to obtain reliable measurements and remote assessments of gait. Deep learning methods are being developed in order to help clinicians in the diagnosis and decision-making process. Locomotor adaptation is impaired in cerebellar patients. Coordinative training aims to improve the coordinative strategy and foot placements across strides, cerebellar patients benefiting from intense rehabilitation therapies. Robotic training is a promising approach to complement conventional rehabilitation and neuromodulation of the cerebellum. Wearable dynamic orthoses represent a potential aid to assist gait. The panel of experts agree that the understanding of the cerebellar contribution to gait control will lead to a better management of cerebellar ataxias in general and will likely contribute to use gait parameters as robust biomarkers of future clinical trials.

Ataxia Prevalence in Primary Orthostatic Tremor

Background

The exact pathophysiology of primary Orthostatic Tremor (OT) is unknown. A central oscillator is assumed, and previous imaging studies show involvement of cerebellar pathways. However, the presence of ataxia on clinical exam is disputed. We set out to study ataxia in OT prospectively.

Methods

EMG-confirmed primary OT subjects and spousal controls received a neurological exam with additional semiquantitative evaluations of ataxia as part of a multinational, prospective study. These included detailed limb coordination (DLC), detailed stance and gait evaluation (DS), and the Brief Ataxia Rating Scale (BARS). Intra- and inter-rater reliability were assessed and satisfactory.

Results

34 OT subjects (mean age = 67 years, 88% female) and 21 controls (mean age = 66 years, 65% male) were enrolled. Average disease duration was 18 years (range 4-44). BARS items were abnormal in 88% of OT patients. The OT subjects were more likely to have appendicular and truncal ataxia with significant differences in DLC, DS and BARS. Ocular ataxia and dysarthria were not statistically different between the groups.

Discussion

Mild-to-moderate ataxia could be more common in OT than previously thought. This is supportive of cerebellar involvement in the pathophysiology of OT. We discuss possible implications for clinical care and future research.

Highlights

Previous studies of Primary Orthostatic Tremor (OT) have proposed pathophysiologic involvement of the cerebellar pathways.However, presence of ataxia has not been systematically studied in OT.This is a prospective comprehensive ataxia assessment in OT compared to controls. Mild-to-moderate appendiculo-truncal ataxia was found to be common in OT.

Alarming levels of stigma toward generalized dystonia: A cross-cultural comparison

Introduction

Although stigma has been linked to poor quality of life, studies examining its prevalence in dystonia are lacking. Our objective was to determine prevalence and predictors of stigma against generalized dystonia in diverse cultural settings.

Method

Participants were 273 (65.9% female) patients and visitors approached at primary care clinics from three populations: León, Nicaragua (92 participants); a mostly-Hispanic Clinic in Omaha, NE USA (85 participants); and a mostly-non-Hispanic population in Omaha, Nebraska (96 participants). Participants learned about generalized dystonia, epilepsy and schizophrenia through reading a small vignette and viewing videos, followed by a questionnaire designed to identify stigma. We compared levels of stigma between dystonia and other conditions at different sites and measured variables that could affect them.

Results

Prevalence of stigma was high toward dystonia (33.00%), similar to epilepsy and lower than schizophrenia. The results showed a complex relationship between the studied variables and level of stigma, especially with age. Female gender predicted more stigmatizing answers. Country of origin, level of education and self-identification of Hispanic ethnicity did not affect stigma. Learning more personal information about the dystonia patient decreased dystonia, a proof that unjustified preliminary negative judgment was present.

Conclusions

Stigma against generalized dystonia was very prevalent across all the communities studied. Demographic and socio-cultural variables had different correlations to level of stigma, underlying the complexity of this problem. The alarming levels of stigma against dystonia justify further studies on how to minimize its impact on our patients.

•

Prevalence of stigma is high toward generalized dystonia.

•

Female gender predicted more stigmatizing answers.

•

Country of origin and ethnicity did not affect stigma against dystonia.

•

Stigma was similar at all levels of education.

The use of smartphone in measuring stance and gait patterns in patients with orthostatic tremor

Orthostatic tremor (OT) is a rare movement disorder characterized by a fast tremor (13–18 Hz) in the lower extremities during stance. Patients with OT typically complain of instability while standing/walking. However, due to the geographical limitation, the standing instability or gait problems in patients with OT cannot be assessed and monitored frequently. The increasing popularity of using smartphone-based accelerometers could be a solution to eliminate this limitation. This study examined the feasibility of using smartphone-based accelerometers to identify the changes in body movement in different standing and locomotor tasks. Twenty patients with OT and seven healthy controls were consented to participate in this study. Subjects stood with eyes open or eyes closed for 20 seconds. They also performed four different locomotor tasks (normal walking, tandem walk, walking on an elevated surface, and obstacle negotiation). When performed different locomotor tasks, patients with OT had a larger acceleration of body movement than controls in the medial-lateral direction (tandem walk: p = 0.026, walking on an elevated surface: p = 0.002, and stepping over the obstacle: p = 0.028). Patients with OT had smaller acceleration of body movement than controls while standing with eyes open in the vertical direction (p = 0.012), in the anterior-posterior direction (p = 0.013) and in the medial-lateral direction (p = 0.011). This study provides objective evidence of balance instability in patients with OT not only while standing but also during different challenging locomotor tasks by using smartphone-based accelerometers.

Clinical approach to tremor in children

Pediatric Movement Disorders encompass a very large and complex group of diseases, among which Tremor is one of the least studied. Evaluation of tremors in kids carries significant challenges, in particular the fact that many tremor etiologies have other associated movement disorders that make tremor identification more difficult. Also, it is sometimes difficult to differentiate tremors from other shaking disorders. Yet, the correct identification of tremor leads to appropriate treatments and sometimes practical cures. Thus, in this paper we have strived to provide a succinct, clinically useful and practical review of pediatric tremors. The most useful classification of tremors in based on their predominance during rest or activity. By far, the most common tremor in children is during action. We provide a clinical algorithm on how to assess pediatric tremors at the bedside, as well as multiple useful tables. We also review common tremor etiologies.

A dozen years of evolution of neurology clerkships in the United States

Objective

To report a 2017 survey of all US medical school neurology clerkship directors (CDs) and to compare the results to similar surveys conducted in 2005 and 2012.

Methods

An American Academy of Neurology (AAN) Consortium of Neurology Clerkship Directors (CNCD) workgroup developed the survey that was sent to all neurology CDs listed in the AAN CNCD database. Comparisons were made to similar 2005 and 2012 surveys.

Results

The response rate was 92 of 146 programs (63%). Among the responding institutions, neurology is required in 94% of schools and is 4 weeks in length in 75%. From 2005 to 2017, clerkships shifted out of a fourth-year-only rotation (p = 0.035) to earlier curricular time points. CD protected time averages 0.24 full-time equivalent (FTE), with 31% of CDs reporting 0.26 to 0.50 FTE support, a >4-fold increase from prior surveys (p < 0.001). CD service of >12 years increased from 9% in 2005 to 23% in 2017. Twenty-seven percent also serve as division chief/director, and 22% direct a preclinical neuroscience course. Forty-nine percent of CDs are very satisfied in their role, increased from 34% in 2012 (p = 0.046). The majority of CDs identify as white and male, with none identifying as black/African American.

Conclusion

Changes since 2005 and 2012 include shifting of the neurology clerkship to earlier in the medical school curriculum and an increase in CD salary support. CDs are more satisfied than reflected in previous surveys and stay in the role longer. There is a lack of racial diversity among neurology CDs.

Bilateral chorea/ballismus: detection and management of a rare complication of non-ketotic hyperglycaemia

Non-ketotic hyperglycaemia (NKH) is the most common metabolic cause of hemichorea-hemiballismus (HC-HB) and an often-reversible condition. A 68-year-old man presented to the emergency department with a severe hyperglycaemic episode and altered mental status. He was treated appropriately and discharged home after his blood glucose levels were normal with an improvement of mental status. Four weeks after the discharge, he returned with flailing movements of bilateral upper and lower limbs. MRI of the brain revealed hyperintensities of the bilateral putamen on T1-weighted imaging. The patient's symptoms improved with a combination of amantadine, clonazepam and tetrabenazine. Several hypotheses involving gemistocytes, calcification and petechial haemorrhage were proposed in support of imaging abnormalities in the striatum. Dopamine-depleting agents and neuroleptics are used in the treatment of chorea. It is recommended to try a dose of tetrabenazine in patients with NKH-induced HC-HB if no improvement is appreciated with initial treatment of glycaemic control.

Hyperbaric oxygen for late sequelae of carbon monoxide poisoning enhances neurological recovery: case report

Neuropsychiatric sequelae have been reported in 15%-45% of survivors of carbon monoxide (CO) poisoning. Hyperbaric oxygen (HBO₂) therapy reduces the incidence of cognitive and neurological a dysfunction. The efficacy of providing HBO₂ beyond the first one to two days after initial insult is unknown. However, some evidence exists for the benefit of this treatment. We report on treating a patient 14 months after CO injury, who responded with markedly improved neurologic status. A 27-year-old scholar was found comatose due to CO poisoning (carboxyhemoglobin = 31.7%). He received five acute HBO₂ treatments. After discharge, he developed chorea, Parkinsonism, dystonia, memory loss, slowed processing speed and verbal fluency, leaving him disabled. After the patient reached a clinical plateau, HBO₂ was tried again at 90 minutes at 2.4 ATA plus air breaks. Neuropsychological testing was performed at baseline and after each 20 HBO₂ cycles, five of which were performed during the period from 14-22 months after CO exposure. After the first 20 treatments, Parkinsonism and dystonia improved. After 40 sessions, further improvements were seen on mental speed, verbal fluency, and fine motor movements. The outcome following 100 treatments was that the patient regained independence, including the ability to drive and to become gainfully employed. Our case calls into question the concept that HBO₂ therapy has no role during the chronic phase of CO brain injury. Randomized clinical trials should be considered to evaluate the therapeutic efficacy of HBO₂ in patients with neurological sequelae following CO injury.

Smartphone Apps Provide a Simple, Accurate Bedside Screening Tool for Orthostatic Tremor

Background

Orthostatic Tremor (OT) is characterized by the presence of a sensation of instability while standing, associated with high frequency (13-18 Hz) lower extremity tremor. Diagnosis is confirmed with surface electromyography (EMG). An accurate screening tool that could be used in the routine clinical setting, without any specialized equipment, would be useful in earlier detection of OT and judicial use of additional testing.

Objective

The objective of this study was to evaluate OT diagnostic test characteristics at bedside using iPhone's built-in accelerometer and available applications for tremor recordings.

Methods

We obtained recordings using iPhones (Model 5, 5s, and 6) and free Applications ("LiftPulse" by LiftLabs [App1] and "iSeismometer" by ObjectGraph LLC [App2]) at default settings.

Results

24 EMG-confirmed OT subjects (mostly females, 22/24) and 15 age-matched controls (mostly males, 11/15) were evaluated. App1 detected OT range tremor in 22/24 patients and none of the controls. (Sensitivity = 92%, Specificity = 100%, NPV = 88%). App2 detected OT range tremor in 21/24 patients and in 1/13 controls (Sensitivity = 88%, Specificity = 92%, NPV = 80%). When combined, 24/24 patients and 1/13 controls had OT range tremor (Sensitivity = 100%, Specificity = 92%, NPV = 100%).

Conclusions

Smartphone apps that use the built-in accelerometer provide a simple, accurate and inexpensive bedside screening diagnostic tool for patients with OT.

The clinical features and functional impact of valproate-induced tremor

BACKGROUND

Tremor is a known side-effect of anticonvulsants, particularly of valproate. However, there is a dearth of information regarding detailed clinical features and functional impact of valproate-induced tremor.

METHODS

We studied a cohort of patients treated with anticonvulsants for neurological disorders, through blinded evaluations using the Clinical Rating Scale for Tremor (CRST); we compared the frequency, severity and functional impact of drug-induced tremor between patients treated with valproate and those treated with other anticonvulsants.

RESULTS

From a cohort of 218 consecutive patients, 171 were fully evaluated; 118 patients were taking valproate alone or combined with other anticonvulsants and 53 patients were taking other anticonvulsants. Mean age (±SD) at evaluation of the cohort was 32 ± 13 years, females represented 55.6% of cases. Tremor was more frequently observed in patients taking valproate particularly postural upper limb tremor: 49% vs. 15% (right-side) (P < 0.001) and 48.3% vs. 13.2% (left-side), (P < 0.001); had a higher total CRST score: 12.14 vs. 3.06 (P < 0.001), and required more frequently treatment for drug-induced tremor: 23.7% vs. 5.6% (P=0.005) compared with patients taking other anticonvulsants. Among 118 patients taking valproate, women had a higher total CRST score compared with men: 14.54 ± 14.9 vs. 9.56 ± 9.55 (P=0.034). A weak correlation between the total CRST score, dose per Kg of valproate and serum levels of valproate were observed.

CONCLUSIONS

Tremor is frequently observed in patients taking valproate and is severe enough to require treatment in about 24% of cases.

RimabotulinumtoxinB in sialorrhea: systematic review of clinical trials

OBJECTIVE

The aim of this study was to examine the efficacy, safety and dosing practices of rimabotulinumtoxinB (BoNT-B) for the treatment of patients with sialorrhea based on a systematic review of clinical trials.

METHODS

A systematic literature review was performed to identify randomized controlled trials and other comparative clinical studies of BoNT-B for the treatment of sialorrhea published in English between January 1999 and December 2015. Medical literature databases (PubMed, Cochrane Library, and EMBASE) were searched and a total of 41 records were identified. Of these, six primary publications that evaluated BoNT-B for the treatment of sialorrhea met criteria and were included in the final data report.

SYNTHESIS

Total BoNT-B doses ranged from 1500 to 4000 units for sialorrhea. Most of the studies in sialorrhea showed statistically significant benefits of BoNT-B versus placebo (range 4-19.2 weeks). BoNT-B was generally well tolerated across the individual studies; most adverse events reported were considered unrelated to treatment. Adverse events considered potentially associated with BoNT-B included: dry mouth, change in saliva thickness, mild transient dysphagia, mild weakness of chewing and diarrhea.

CONCLUSIONS

BoNT-B significantly reduces sialorrhea at doses between 1500 and 4000 units. The relatively mild dose-dependent adverse events suggest both direct and remote toxin effects.

Botulinum toxin in the management of blepharospasm: current evidence and recent developments

Blepharospasm is a focal (although usually bilateral) dystonia of the orbicularis oculi muscles, producing excessive eye closure. This produces significant disability through functional blindness. Botulinum neurotoxins (BoNT) have become the treatment of choice for blepharospasm; the impressive response rate and the tolerable safety profile have been proven through multiple clinical studies. There are currently four BoNT approved in the United States for different indications - we review the data on blepharospasm for each of these drugs. Currently, incobotulinumtoxinA and onabotulinumtoxinA have the most evidence of benefit for patients with blepharospasm. Current evidence, recent development and future directions are discussed.

Speech-induced atrial tachycardia: an unusual presentation of supraventricular tachycardia

A 63-year-old male radio announcer was admitted with a narrow complex, long RP tachycardia. While in the awake state, the patient spoke in his radio voice, initiating and maintaining the tachycardia. Three-dimensional electroanatomic mapping during electrophysiology study localized the tachycardia to the ostium of the right superior pulmonary vein. After single radiofrequency energy application, no further arrhythmias were inducible with speech. At more than 1 year of follow-up, the patient had no recurrences and continues to work as a radio announcer.

Neuromagnetic evidence of abnormal movement-related beta desynchronization in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder associated with debilitating motor, posture, and gait abnormalities. Human studies recording local field potentials within the subthalamic nucleus and scalp-based electroencephalography have shown pathological beta synchronization throughout the cortical–basal ganglia motor network in PD. Suppression of such pathological beta synchronization has been associated with improved motor function, which may explain the effectiveness of deep-brain stimulation. We used magnetoencephalography (MEG) to investigate neural population-level beta responses, and other oscillatory activity, during a motor task in unmedicated patients with PD and a matched group of healthy adults. MEG is a noninvasive neurophysiological technique that permits the recording of oscillatory activity during movement planning, execution, and termination phases. Each of these phases was independently examined using beamforming to distinguish the brain areas and movement phases, where pathological oscillations exist during motor control. Patients with PD exhibited significantly diminished beta desynchronization compared with controls prior to and during movement, which paralleled reduced alpha desynchronization. This study is the first to systematically investigate neural oscillatory responses in PD during distinct stages of motor control (e.g. planning, execution, and termination) and indicates that these patients have significant difficulty suppressing cortical beta synchronization during movement planning, which may contribute to their diminished movement capacities.

Deep brain stimulation of globus pallidus interna, subthalamic nucleus, and pedunculopontine nucleus for Parkinson's disease: which target?

Deep brain stimulation (DBS) is an accepted therapy for people with Parkinson's disease (PD) motor symptoms that are refractory to pharmacologic therapy. Standard DBS targets are globus pallidus interna (GPi) and subthalamic nucleus (STN). The pedunculopontine nucleus (PPN) is being investigated as a novel target. Which target provides the best outcomes is unknown. The utility of GPi and STN as targets has been confirmed in numerous studies, including randomized comparisons of GPi DBS and STN DBS that demonstrated no difference in motor outcomes. DBS at either site improves appendicular motor symptoms, but beneficial effects on axial manifestations of PD such as postural instability or gait dysfunction (PIGD) are less apparent. PPN has been introduced as a DBS target due to failure of GPi and STN DBS to improve PIGD. Small observational studies indicate improved PIGD with PPN DBS, but small blinded trials show only subjective reduction in falls with no other impact on PIGD or other PD manifestations. No single DBS target is superior to the others. Each target offers relative advantages. Further studies are needed to better define the roles of each target, particularly PPN. Choice of target should be individualized according to providers' preferences and patients' needs.

Calibrated finger rub auditory screening test (CALFRAST)

BACKGROUND

Determination of auditory function is a fundamental part of a complete neurologic examination. Disability from permanent hearing loss is common in the general population. Current bedside auditory tests are unreliable and cumbersome. We evaluated the calibrated finger rub auditory screening test (CALFRAST) as a routine diagnostic tool.

METHODS

The sound spectrum and mean peak intensities of standard finger rub were measured, as well as background noise. CALFRAST overlapped the frequency spectrum of normal speech. Patients and companions were recruited from a neurology clinic. With arms extended, two stimulus intensities were presented: strong finger rub (CALFRAST-Strong 70) and the faintest rub that the examiner could hear (CALFRAST-Faint 70). With subjects' eyes closed, each ear's CALFRAST threshold was ascertained and then compared with its audiometric measure. The normal threshold was considered to be 25 dB. Validity, reliability, and discrimination abilities were obtained using standard methods.

RESULTS

Two hundred twenty-one subjects (442 ears; 58% women) were examined. Ages ranged from 18 to 88 years, with a mean of 46 years. Eighty-five subjects (39%) had some degree of hearing loss. Both specificity and positive predictive value of CALFRAST-Strong 70 were 100%. Both sensitivity and negative predictive value of CALFRAST-Faint 70 were 99%, with a negative likelihood ratio <0.1. Area under the receiver operating characteristic curve was 0.94, consistent with excellent discrimination ability. Both intrarater and interrater reliability were excellent, both kappa >0.8. Subjects' self-assessment of hearing was unreliable.

CONCLUSION

The calibrated finger rub auditory screening test (CALFRAST) is simple, accurate, inexpensive, and reliable. As a routine screening tool, CALFRAST may contribute to more efficient identification of auditory impairment.

Focal dystonias of the hand and upper extremity

Hand dystonia can cause substantial functional disability and is frequently misdiagnosed. In general, dystonia is a disabling disorder of motor control characterized by excessive muscle contractions that can produce involuntary movements and abnormal postures. Prevalence of dystonia can be as high as 1 in 2500 people. Dystonias can be classified based on etiology, age of onset, anatomical part affected, and their tempo. Etiologically, they are classified as primary when the dystonia is the main sign and the cause is genetic or unknown and secondary when there are other disease manifestations and the cause may be identifiable. Dystonias that start before 27 years of age are called childhood-onset dystonia; they usually start in the lower limbs, trunk, or upper extremities and frequently spread to the rest of the body. Adult-onset dystonias usually begin in the upper half of the body, and the risk of progression to other body parts depends on the anatomic site of onset. Anatomically, dystonias can be focal (1 body part), segmental (2 or more contiguous body parts), multifocal (2 noncontiguous areas), hemidystonia, or generalized. Based on their tempo, dystonias can be constant, intermittent, or situational, the latter including task-specific dystonias. The rest of the review focuses on the clinical manifestations, differential diagnosis, pathophysiology, and treatment of hand dystonia.

Task-specific dystonias: a review

Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer's cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions.