Involuntary movements in the elderly. Parkinson's disease and other causes.

Dyskinesia is usually lifelong and progressive; therefore, physicians generally see the disorder in elderly patients. Medical treatment must be carefully selected on the basis of the cause of the dyskinesia. Parkinsonian dyskinesia is well controlled by drug therapy. However, patients can become less responsive to a drug after years of use and may experience unwelcome side effects. Cerebellar tremor is extremely disabling because it worsens with activity, but no satisfactory therapy is available. Senile, essential, and familial tremors are also intensified by action, but they can often be suppressed with a mild tranquilizer or a beta blocker. Drug treatment of blepharospasm and spastic dysphonia has been disappointing: Facial or laryngeal surgery is sometimes required. Tardive dyskinesia is caused by neuroleptic drugs, so the only therapy for the disorder is withdrawal of the offending drug.