The hand that has forgotten its cunning--lessons from musicians' hand dystonia.

Focal task-specific dystonia of the musicians' hand (FTSDmh) is an occupational movement disorder that affects instrumental musicians and often derails careers. There has been speculation on the role of intense practice or the specific technical demands of various instruments as triggers for the development of FTSDmh. In this study, we review the clinical features of all published cases (899 patients) and 61 previously unpublished cases of FTSDmh. Our primary goals were to search for patterns in the clinical phenotype, and to discern if specific instrumental technical demands might be related to the development of dystonia. Symptoms of FTSDmh began at a mean age 35.7 years (SD = 10.6), with an overwhelming male predominance (M:F = 4.1:1). The right hand was preferentially affected in keyboard and plucked string players (77%), and the left hand in bowed string players (68%). Flexion movements were the most common dystonic movement in each instrument class, and fingers 3, 4, and 5, either in isolation or combination, were most frequently involved. The clinical implications of these findings and their possible relationship to the pathophysiology of focal task-specific dystonia are explored.