Writer’s cramp: is focal dystonia the best explanation?

Abstract

Often considered no more than an historical curiosity, writer’s cramp remains an important disability in the workplace and the mechanism, which has puzzled the best medical minds for generations, remains contentious. A remarkable range of hypotheses has been put forward to try and explain a disability which periodically reached epidemic and economically worrying levels, but in the end medical opinion has accepted the explanation put forward by neurologists Sheehy and Marsden in 1983 that this was caused by a form of focal dystonia. However, the majority of the historical descriptions of writer’s cramp do not fit the classical parameters of focal dystonia and are more accurately described as a progressive forearm muscle fatigue. Today’s keyboard operators continue to complain of symptoms identical to their clerical forebears demonstrating that this is a problem which has evolved but not disappeared; this has the paradoxical advantage that modern research techniques enable this complaint to be revisited. The result shows that two varieties of writer’s cramp have always existed and while focal dystonia remains a valid explanation for a minority of cases, the much more common fatigue-based complaint is better explained by chronic compartment syndrome of the forearm.