Musicians' Hand Dystonia
Abstract & Commentary
By Claire Henchcliffe, MD, DPhil Assistant Professor, Department of Neurology and Neuroscience, Weill Medical College, Cornell University. Dr. Henchcliffe reports she is on the speaker's bureau for GlaxoSmithKline, Teva, Boehringer Ingelheim, Schwarz Pharma, and Allergan.
Synopsis: This case review of 960 patients details the clinical features of musicians' hand dystonia, a potentially disabling focal task-specific dystonia often beginning at peak-career. Cases were predominantly male, with onset typically in the fourth decade and most commonly affecting the third digit or contiguous fingers on the ulnar side.
Source: Conti AM, Pullman S, Frucht SJ, et al. The hand that has forgotten its cunning lessons from musicians' hand dystonia. Mov Disord 2008;23:1398-1406.
The authors identified 899 published cases from 43 journal articles on focal task-specific dystonia of the musicians' hand (FTSDmh). They included an additional 61 cases identified at a large academic movement disorders center. Of the authors' 61 cases, the majority were pianists (n=17) or guitarists (n=16), followed by violinists (n=5), drummers (n=5), and flautists (n=4), but also included musicians playing bagpipes, accordion, and others. Mean age of symptom onset was 35.7 ± 10.6 years for the 239 subjects with available data, and the overwhelming majority described were male (80%). Of the 409 cases with available data, the right hand was involved in 64%, the left hand in 32%, and both hands in 4%. Only one individual had a first-degree relative with focal dystonia (spasmodic dysphonia), but family history was not reported in most publications included. The authors then attempted to define a pattern of dystonia. If a single digit was affected (81 cases with available data), the third digit was the most commonly involved (37%), but if multiple digits were affected (189 cases with available data), the most frequent patterns were fourth + fifth (32%), third + fourth (17%), or third + fourth + fifth (10%). Finger flexion was the most common involuntary movement recorded, but more complex movements also occurred.
Commentary
FTSD of the hand is thought to represent a maladaptive response involving central nervous system plasticity to repeated, stereotyped movements demanding a high degree of skill and attention. It is estimated to affect 1/200 musicians. Although it presents a diagnostic difficulty, recognition of the disorder is increasing with exploration of expanded treatment options (such as botulinum toxin injections and limb immobilization), emergence of multidisciplinary programs dedicated to treating performing artists, and efforts made to raise awareness by sufferers of musician's dystonia. Risk factors are hard to define, although a genetic component has been suggested and one of the authors has reported three families in which one member had FTSD and relatives had other focal dystonias (mainly writer's cramp). Isolated cases associated with peripheral nerve trauma also have been reported. The authors comment that they are struck by similarities between FTSDmh and writer's cramp, and certainly body location and age of onset is comparable. There are distinctions though, as the authors point out that only 4% of individuals in this series had bilateral hand FTSD, whereas symptoms spread to the opposite hand in writer's cramp in approximately one third. Predisposing activities also are different: those with FTSDmh typically focus on their practice for many hours each day, compared with those with writer's cramp who often have a quite typical time frame for writing; this raises the question of whether environmental influence weighs differently upon the two conditions. More objective findings supporting this difference between the two types of dystonia have emerged. For example, one study found that a vibratory input, used as a sensory stimulus to a specific hand muscle, strongly affected short-latency cortical inhibition (as recorded by transcranial magnetic stimulation) in those with FTSDmh, whereas it had very little effect in those with writer's cramp. This emphasizes that our knowledge of other focal dystonias must be applied with caution to FTSDmh, and understanding more about specific neurophysiological alterations might allow us to more rationally design and monitor novel therapies. The present study represents the largest study to date of FTSDmh. Despite its limitations (for example reporting and referral bias, limited data published on individual cases), the authors succeed in defining a typical age of onset and a significant gender bias. Moreover, they uncover some intriguing patterns particularly in dystonia involving multiple digits, presumably reflecting somatotopic spread of abnormal responses, depending upon the precise demands made by their practice and performance. The authors, therefore, provide an extremely valuable resource for clinicians wishing to learn more about this disorder.
This case review of 960 patients details the clinical features of musicians' hand dystonia, a potentially disabling focal task-specific dystonia often beginning at peak-career. Cases were predominantly male, with onset typically in the fourth decade and most commonly affecting the third digit or contiguous fingers on the ulnar side.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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