Prevalence of abnormal involuntary movements ("spontaneous dyskinesias") in the normal elderly.

Advancing age has been associated with increased prevalence of abnormal involuntary movements in neuroleptic-treated patients. In order to investigate the possibility that the aging process itself might produce involuntary movements clinically indistinguishable from tardive dyskinesia, a group of healthy elderly volunteers were systematically examined. A 4% prevalence rate of mild involuntary movements was found, suggesting that the aging process itself is not likely to produce dyskinesias without other contributing factors coming into play.