Task-specific Tremor Research Articles

Characteristics of Task-specific Tremor in String Instrument Players

Characteristics of Task-specific Tremor in String Instrument Players

Characteristics of Task-specific Tremor in String Instrument Players.

BackgroundIn recent studies primary bowing tremor has been described; however, tremor frequency has never been quantitatively assessed. In addition to describing phenomenological aspects of tremor we thus aimed at assessing tremor frequency. Our hypothesis was that primary bowing tremor is similar to the phenomenological aspects and frequency of primary writing tremor.MethodsWe quantified primary bowing tremor in four violinists under two conditions: open strings and a G major scale. Data were analyzed using empirical mode decomposition because it takes into account non-stationarity and non-linearity of signals. For each patient we further described tremor phenomenology and assessed symptom onset, risk factors, medication, and family history with a structured anamnesis. We compare the findings to previous findings for primary bowing tremor and primary writing tremor.ResultsWe mainly found a flexion–extension tremor of the wrist with a frequency range of 4.7–6.7 Hz. There was no significant difference between the conditions. Mean onset age was 43±2.4 years. Medication included trihexyphenidyl, propranolol, primidone, and botulinum toxin. We found a positive family history in two patients and an injury prior to symptom onset in another two patients. Comparison of onset age, frequency range, family history, and injuries prior to onset revealed that our findings are very similar to previous findings on primary bowing tremor and primary writing tremor.DiscussionOur findings confirmed our hypothesis that primary bowing tremor is similar to primary writing tremor, with regard to phenomenology and epidemiology as well as tremor frequency. There was no difference in tremor frequency between conditions, suggesting that tremor is not influenced by bimanual coordination or bowing speed. Our findings thus provide new phenomenological aspects and may contribute to a better understanding of primary bowing tremor.

Analysis of dystonic tremor in musicians using empirical mode decomposition

ObjectiveTest the hypotheses that tremor amplitude in musicians with task-specific dystonia is higher at the affected finger (dystonic tremor, DT) or the adjacent finger (tremor associated with dystonia, TAD) than (1) in matched fingers of healthy musicians and non-musicians and (2) within patients in the unaffected and non-adjacent fingers of the affected side within patients. MethodsWe measured 21 patients, 21 healthy musicians and 24 non-musicians. Participants exerted a flexion–extension movement. Instantaneous frequency and amplitude values were obtained with empirical mode decomposition and a Hilbert-transform, allowing to compare tremor amplitudes throughout the movement at various frequency ranges. ResultsWe did not find a significant difference in tremor amplitude between patients and controls for either DT or TAD. Neither differed tremor amplitude in the within-patient comparisons. ConclusionBoth hypotheses were rejected and apparently neither DT nor TAD occur in musician’s dystonia of the fingers. SignificanceThis is the first study assessing DT and TAD in musician’s dystonia. Our finding suggests that even though MD is an excellent model for malplasticity due to excessive practice, it does not seem to provide a good model for DT. Rather it seems that musician’s dystonia may manifest itself either as dystonic cramping without tremor or as task-specific tremor without overt dystonic cramping.

Pronounced Task Specific Writing Tremor in Parkinson's Disease (P3.079)

Pronounced Task Specific Writing Tremor in Parkinson's Disease (P3.079)

Coherence of coactivation and acceleration in task-specific primary bowing tremor

Coherences between coactivation of wrist antagonist muscles and movement fluctuation were assessed in four violinists with a task-specific tremor and four age-matched healthy violinists using electromyography and accelerometer. We found coherence between individual muscular activation and tremor only in patients at a frequency range of 3-8 Hz. The finding corroborates the notion that primary bowing tremor emerges mainly due to central neurogenic contributions via motor-unit synchronization. Furthermore, the coherence between the muscular coactivation and tremor suggests a relation of the tremor to dystonia.

Task‐specific tremor in violinists: Evidence of coactivation in the 3 to 8 Hz frequency range

Task-specific tremor in musicians severely impairs fine motor control. However, little is known about its pathophysiology. Here, we quantify electromyography (EMG) properties in primary bowing tremor-in particular, muscular coactivation-to determine whether primary bowing tremor affects a specific frequency range of coactivation. We quantitatively compared EMG properties of the wrist muscles between 4 professional violinists who had task-specific tremor and 4 age-matched healthy controls. We observed bowing tremor-specific muscular coactivation in the frequency range of 3 to 8 Hz only in the patients but not in the healthy controls. No muscular activity was observed at the resonance-frequency range. Our findings indicate an association between coactivation and bowing tremor at a specific frequency range (3-8 Hz). The absence of EMG activity and coactivation in the mechanical-reflex frequency of the wrist suggests that central mechanisms play a more dominant role than mechanical-reflex mechanisms in primary bowing tremor.

A Review of Primary Writing Tremor

ABSTRACTA task-specific tremor (TST) is a rare form of movement disorder that appears while performing or attempting to perform a particular task. Primary writing tremor (PWT) is the most common form of TST which only occurs during the act of writing and hinders it. (Bain PG, Findley LJ, Britton TC, Rothwell JC, Gresty MA, Thompson PD, Marsden CD. MRC Human Movement, and Balance Unit, Institute of Neurology, London, UK. Primary writing tremor. Brain. 1995;118(6):1461–72.) Primary writing tremor type B is present not only during the act of writing but also when the hand assumes a writing posture. (Bain PG, Findley LJ, Britton TC, Rothwell JC, Gresty MA, Thompson PD, Marsden CD. MRC Human Movement and Balance Unit, Institute of Neurology, London, UK. Primary writing tremor. Brain. 1995;118(6):1461–72.) We first of all describe a remarkable case study of a 50-year old, right-handed male who started experiencing a primary writing tremor in his right hand about a year ago. This case was found to be of particular interest because the patient had it relatively difficult when attempting to write numbers as opposed to writing letters. This review further discusses the clinical manifestations of PWT. In addition, three main hypotheses have been proposed for the causation of PWT, although the exact pathophysiology of PWT still remains unknown. It has been suggested that PWT is a separate entity, a variant of essential tremor and not a separate entity, or a type of dystonia. The various treatment options for PWT are discussed including botulinum toxin and oral pharmacotherapy.

Task-Specific Writing Tremor: Clinical Phenotypes, Progression, Treatment Outcomes, and Proposed Nomenclature

ABSTRACTTask-specific tremor diagnoses remain controversial. We evaluated 56 subjects seen with writing tremor. The diagnosis was made if there was a clear history of exclusive tremor while writing for at least 3 years before noticing tremor in any other scenario and the continued presence of writing tremor as the most prominent aspect of their tremor disorder on examination. The age of tremor onset was 47.2 ± 18.0 years (73.2% male). Ethnic backgrounds were Caucasian (68.4%), African (23.2%), Hispanic (5.2%), and Asian/Indian (3.3%), and 44% reported any tremor in a first degree relative. Writing tremor often progressed to other task-specific tremors or rest tremor but not to immediate postural tremor, as usually seen in essential tremor. The other tremor provoking scenarios were eating/drinking (14), brushing teeth/shaving/make-up (5), typing (2), suture removal (1), and drafting (1) and occurred a mean of 7.5 years after the onset of writing tremor. Fourteen developed a “rest” (true rest or crescendo) tremor but only 2 of these met clinical criteria for Parkinson's disease. Pharmacologic treatments of writing tremor, including with ethanol, were generally poor, whereas deep brain stimulation of the ventral intermediate (VIM) thalamus was successful. Compared with patients with “classic” essential tremor in our clinic, writing tremor patients were more likely African, more likely male, had an older age of onset, a lower likelihood of familial tremor, and were more refractory to tremor medications and ethanol. This supports segregation between task-specific tremor and essential tremor but does not support the specific diagnosis of “writing tremor” because many patients progress to tremor with other tasks.

Disappearance of writing tremor after striatal infarction

Primary writing tremor (PWT) is a task-specific tremor caused by writing or similar motor activities. It has been characterized as a type of focal dystonia related to writer's cramp as well as a form of essential tremor.1 Disappearance of an essential tremor after stroke has been rarely reported.2 However, cessation of a writing tremor following a stroke has not yet been documented. We describe a patient who had complete resolution of PWT after a discrete contralateral striatal infarction. Increased thalamic inhibition, to the over-activated motor cortex, could be the underlying mechanism for cessation of PWT in such cases. A 70-year-old hypertensive right-handed man was admitted to our hospital with mild right hemiparesis. Prior to admission, the patient reported recurrent right hemiparesis over the prior 2 days with a duration of 5 to 30 minutes. At admission the examination revealed an alert man with a mild right hemiparesis (Medical Research Council Score = 5– out of 5) and no other remarkable neurologic …

Isolated high‐frequency jaw tremor relieved by botulinum toxin injections

Jaw tremor can be seen as a component of various neurological disorders such as essential tremor, Parkinson's disease, dystonia, branchial myoclonus, hereditary geniospasm, task-specific tremor, and Whipple's disease, as well as in normal situations such as shivering, and subclinical physiological jaw tremor. In most of these conditions, the jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, and its frequency is lower than 12 Hz. Schrag and colleagues reported a patient with a high-frequency idiopathic jaw tremor, and they speculated it could be related to orthostatic tremor affecting the masseter muscles. We encountered a similar patient with intermittent rapid focal jaw tremor that was successfully treated with botulinum toxin injections to the masseters.

Primary writing tremor: motor cortex reorganisation and disinhibition

Primary writing tremor (PWT) is a task-specific tremor of uncertain origin. There has been debate as to whether PWT represents a variant of essential tremor or a tremulous form of focal dystonia related to writer's cramp. In writer's cramp there is evidence of changes in intracortical inhibition (ICI), as well as cortical motor reorganisation. To study corticomotor organisation and short-latency ICI in a patient with typical task-specific PWT. Transcranial magnetic stimulation mapping of the corticomotor representation of the hand and studies of ICI using paired-pulse stimulation were performed in a 47-year-old right-handed woman with a pure task-specific writing tremor. The motor maps for the hand were displaced posteriorly on both sides and reverted to a normal position after treatment with botulinum toxin. Short-latency ICI was reduced for the dominant hand. The findings indicate reorganisation and disinhibition of the corticomotor projection to the hand and point to the participation of cortical centres in the origin of PWT.

Bilateral primary writing tremor.

Primary writing tremor is a task-specific tremor that is considered to be unilateral. We report a 59-year-old man with a 5-year history of a typical primary writing tremor in the right hand who developed similar symptoms in the left hand. Copyright 1998 Lippincott Williams & Wilkins

Primary writing tremor.

Primary writing tremor (PWT) is considered to be a type of task-specific tremor in which tremor predominantly occurs and interferes with handwriting. We describe the clinical and neurophysiological features of 21 patients (20 male and one female) with PWT. Mean age at tremor onset was 50.1 years. A family history of PWT was obtained from seven patients. Ten patients obtained benefit from drug treatment (mainly propranalol or primidone) and seven responded to alcohol. The writing speeds of the patients (mean +/- SEM: 73.1 +/- 6.6 letters per minute) when using their preferred hand were significantly reduced (Student's t test: P < 0.001) compared with those of healthy control subjects (mean +/- SEM: 127.7 +/- 6.4). Surface polymyography performed during writing showed 4.1-7.3 Hz rhythmic activity predominantly in the intrinsic hand and forearm muscles. Alternating, extensor activation alone, skipping from alternating to extensor activation, and co-contracting EMG patterns were recorded from the flexor and extensor muscles of the forearm. There was no evidence for excessive 'overflow' of this rhythmic EMG activity, as similar activity was detected in comparable muscle groups of healthy control subjects. Accelerometry confirmed that the frequency of PWT ranged from 4.1-7.3 Hz (median 5.5 Hz) and that normal subjects wrote with a 4.0-7.7 Hz oscillation (median 4.6 Hz). Forearm reciprocal inhibition was normal in PWT (n = 13), and thus patients with PWT can be distinguished from those with writer's cramp in whom decreased presynaptic inhibition has been found. Patients were sub-classified as having either type A (n = 11) or B (n = 10) PWT depending on whether tremor appeared during writing (type A: task induced tremor) or whilst writing and adopting the hand position used in writing (type B: positionally sensitive tremor). However, the only differences between these two groups were that a co-contracting EMG pattern and tremor induced by tendon taps to the volar aspect of the wrist were present in type B but not type A cases.

Focal task-specific tremor and dystonia: categorization of occupational movement disorders.

We studied 28 patients with focal task-specific disorders. Three groups were identified, according to the occurrence of focal tremor alone (group I, n = 10), dystonia alone (group II, n = 8), and tremor-dystonia combination (group III, n = 10). Four of six patients in groups I and III showed improvement with beta blocking agents alone, and another patient improved with primidone and metoprolol. Four of seven patients in groups II and III improved at least moderately with only anticholinergic medication. The coexistence of focal tremor and focal dystonia in the same limb in 10 patients (group III) suggests a link between these focal disorders. We conclude that focal tremor and focal dystonia are related to generalized essential tremor and generalized dystonia. A scheme which conceptualizes these interrelationships is proposed.