 Testing of limb function will be performed according to standard clinical rating scales, including the modified Ashworth spasticity scale and the Barry-Albright Dystonia rating scale. Electrophysiological testing of hand function will involve moving finger muscles against resistance while surface electromyographic signals EMG are monitored for the ability to activate one finger at a time while minimizing muscle co-contraction and overflow. Testing of arm function will involve measurement of the ability to relax the biceps and triceps and the resistance of the elbow to passive movement by the examiner. 