Treatment of hyperkinetic movement disorders.

Parkinson's disease, the most common hypokinetic movement disorder, has received much attention from the clinical and scientific community, but there has been a relative paucity of comprehensive reviews of hyperkinetic disorders, even though they are equally or even more disabling. Hyperkinetic movement disorders include tremors, dystonia, chorea, tics, myoclonus, stereotypies, restless legs syndrome, and various other disorders with abnormal involuntary movements. Substantial progress has been made in the understanding of the role of the basal ganglia in the pathophysiology of these hyperkinesia disorders and in motor control, muscle tone, posture, and cognitive processes. Although therapies that target pathogenesis are still lacking, effective management of hyperkinetic movement disorders demands that physicians are knowledgeable about current and novel pharmacological and surgical approaches. In addition to tetrabenazine, a monoamine-depleting drug, new formulations of botulinum toxin are being increasingly used in the treatment of these movement disorders. Finally, success with surgical approaches, particularly deep brain stimulation in patients with Parkinson's disease who have levodopa-induced dyskinesias, has been extended to the treatment of many hyperkinetic movement disorders.