Pharmacological approaches to treatment of hemiballism and hemichorea.

Hemiballism is an involuntary uncontrollable movement disorder with grave prognosis. Post stroke anatomical lesions of the subthalamic nucleus are the most frequent but not sole site. Increased cerebrospinal fluid homovanillic acid levels and successful management of hemiballistic symptoms with neuroleptics have suggested a dopaminergic overactivity as the neurochemical pathology. Diazepam, a gamma amino butyric acid (GABA) mimetic drug, has recently been reported to possess therapeutic efficacy. Hemiballism is a treatable condition which responds to neuroleptics and possibly GABA mimetic drugs.