Extreme task specificity in writer's cramp.

BACKGROUND: Focal hand dystonia may be task specific, as is the case with writer's cramp. In early stages, task specificity can be so specific that it may be mistaken for a psychogenic movement disorder. METHODS: We describe 4 patients who showed extreme task specificity in writer's cramp. They initially only had problems writing either a single letter or number. Although they were largely thought to be psychogenic, they progressed to typical writer's cramp. CONCLUSIONS: Early recognition of this condition may provide an opportunity for early initiation of treatment.