Primary writing tremor: report of a case successfully treated with botulinum toxin A injections and discussion of underlying mechanism.

Primary writing tremor (PWT) is a rare motor disorder of unknown etiology, where tremor is elicited primarily or exclusively with writing. We describe a patient with PWT, present a video before and after successful treatment with botulinum toxin type A injections, and discuss a possible underlying dystonic mechanism. Copyright (c) 2005 Movement Disorder Society.