Evidence for the effectiveness of botulinum toxin for writer's cramp.

We performed a comprehensive literature search of clinical studies published between 1989 and 2007 concerning the use of botulinum neurotoxin (BoNT) in the treatment of writer's cramp (WC). Publications were categorized as Classes I-IV using the scale developed by the Therapeutics and Technology Assessment (TTA) subcommittee of the American Academy of Neurology. Our search resulted in 17 clinical publications discussing the treatment of WC with BoNT. The literature search results were: one publication being Class I, two being Class II, 11 being Class III, and three being Class IV.