Difficultés d'inclure, les patients sont rares

Writer's cramp (WC) is a focal dystonia characterized by abnormal movements and postures during writing. Limited finger independence during writing manifests as difficulty suppressing unwanted activations of neighbouring non task-relevant fingers. WC patients also have difficulty in fine control of grip force. However, some previous studies indicate positive effects of individual finger movement training in WC although these studies lacked enhanced visual feedback of activations in 'stationary' fingers. The investigators have recently developed the Finger Force Manipulandum which quantifies the forces applied by the fingers in different tasks. This method is sensitive for detection and quantification of small unwanted contractions in non-active ('stationary') fingers. Forces in 'stationary' fingers can be displayed on-line providing enhanced feedback on independence of finger movements. The aim of this study is to test the effectiveness of finger individuation training using the FFM to improve symptoms in WC patients.

Inclusion Criteria:

• writer's cramp (diagnostic confirmed by a neurologist specialized in movement disorders
• handwriting speed < 140 letters per minute
• simple or complex writer's cramp
• scholarship in French language
• absence of treatment by botulinum neurotoxin, or last injection > 3 months
• age > 18 and < 71 years
• informed consent
• medical insurance coverage

Exclusion Criteria:

• writer's cramp with no impact on writing
• writing tremor
• other neurological disease with effect on writing
• pain or traumatism of the limb used for writing, requiring medical or surgical treatment in the last preceding months
• participation in another research with a potential impact on evaluation criteria
• pregnant or breast feeding patient
• patient under judiciary protection