A prognostic factor in focal hand dystonia: typist's cramp cases and literature review.

The prognosis of focal hand dystonia (FHD) remains unclear. We retrospectively studied six patients with typist's cramp in our hospitals, and five cases in the PubMed database. All of them were right-handed. We compared clinical features between simple (dystonia in only one specific task), and dystonic/progressive groups (dystonia in several and/or new tasks). The initially affected right hand ratio was significantly higher in dystonic/progressive groups than in simple group (p=0.015). Initially affected hand may be a predictor for the progression, implying that the progression may be associated with the amount of daily routine hand movements.