RESULTS: Three children withdrew due to non-serious adverse events (chorea, drug rash, hyperactivity). 3 children reduced dosage due to non-serious adverse events. The 23 children who completed the study showed a significant improvement in arm function at 15 weeks (p=0.045) but not at 9 weeks. Post-hoc analysis showed that a subgroup (N=10) with hyperkinetic dystonia worsened at 9 weeks (p=0.04) but subsequently returned to baseline following taper of the medicine.