Figure 1.

Clinical examples of primary dystonia. a | Writer’s cramp. Abnormal clenching of fingers occurs selectively during writing; patient is otherwise normal. b | Dystonia of arm, neck and face, exacerbated during writing. Patient first developed writer’s cramp, but subsequently developed dystonia of the neck (torticollis) and face. c | Fixed dystonic foot posture. d | Involuntary dystonic flexion of trunk and extension of neck (retrocollis) during gait.