Seven children between 2 and 15 years of age with cerebral palsy and upper 
extremity dystonia were enrolled in an open-label, dose-escalation pilot 
clinical trial of botulinum toxin type B (Myobloc), injected into the biceps and 
brachioradialis muscles of I or both arms. The primary outcome measure was the 
change in maximum speed of hand movement during attempted forward reaching. 
Escalating doses of 12.5, 25, and 50 U/kg per muscle were injected at each of 3 
visits. Reaching speed improved in response to injection, and dystonia scores on 
the Burke-Fahn-Marsden dystonia scale, the Unified Dystonia Rating Scale, and 
the Unified Parkinson's Disease Rating Scale improved. There was not a 
dose-related effect on efficacy. There were no serious adverse events. Two 
children reported transient weakness. These results support the use of botulinum 
toxin type B as a safe and effective treatment for upper extremity dystonia in 
children with cerebral palsy. Larger controlled trials are needed to confirm 
these results.