• The primary outcome measure is the time it takes to complete maximum arm extension during voluntary reaching, measured from the coraco-acromial joint to the midpoint of the dorsum of the wrist.
  

• The rater will compare improvement or worsening in global arm function through the Unified Dystonia Rating Scale (UDRS), the motor subscale of the Unified Parkinson’s Disease rating scale (UPDRS), and the Burke-Fahn-Marsden dystonia scale (BFM). Compar
  

Subjects: 10 subjects age 2-17 years with hypertonia affecting one or both upper extremities, but without injections of neuromuscular blocking agents for six months prior to enrollment, or surgery on the upper extremity. Intervention: Injection of Myobloc™ in 2 sites per muscle for up to two muscles of each upper extremity (biceps, brachioradialis), at a maximum dose of 25Units/kg/arm for the first injection, a maximum of 50Units/kg/arm for the second injection, and a maximum of 100Units/kg/arm for the third injection. If there is significant weakness or worsening of function following any injection, the dose will not be increased for subsequent injections.

Injections will be performed after placement of topical anesthetic (ELA-MAX™ cream), using EMG guidance to identify active muscles contributing to hypertonia. Primary outcome measures: The primary outcome measure is the time it takes to complete maximum arm extension during voluntary reaching, measured from the coraco-acromial joint to the midpoint of the dorsum of the wrist.

Change scores will be calculated between intake and 1 month (baseline effect), 1 month and 2 months (first injection effect), 4 months and 5 months (second injection effect), and 7 months and 8 months (third injection effect). A device called a Shape Tape (Measureand, Inc.) will be used to measure this outcome. Shape Tape is a flexible strip of portable spring steel with optic fiber that provides instantaneous readouts to a portable computer of bends and twists and other forms of movement capture that can be conducted in a clinical setting. The Shape Tape is fastened loosely to the body part under measurement (in this case, the subject’s wrist and shoulder) with either medical-grade adhesive tape or Velcro. The shapetape is connected to a portable computer, and custom software allows measurement of the average velocity of hand movement during reaching.

Secondary outcome measures: The rater will compare improvement or worsening in global arm function through the Unified Dystonia Rating Scale (UDRS), the motor subscale of the Unified Parkinson’s Disease rating scale (UPDRS), and the Burke-Fahn-Marsden dystonia scale (BFM). Comparisons will be performed between intake and 1 month (baseline effect), 1 month and 2 months (first injection effect), 4 months and 5 months (second injection effect), and 7 months and 8 months (third injection effect). Other secondary measures include neurological examination, Ashworth spasticity scale, and comparisons of numerical stiffness measures as measured by the Rigidity Analyzer Device. A parent rating scale, the Pediatric Quality of Life Inventory (PedsQL), will be used to determine overall functional improvement. Statistical analysis: The outcomes will be tested at the 0.05 level of significance using repeated-measures analysis of variance (ANOVA) and the Friedman nonparametric test applied to the 4 repeated change scores for each of the primary and secondary outcome measures. Tests of significance for the secondary measures will be corrected for multiple comparisons.