Myoclonus and parkinsonism

We have observed three patients in whom the onset of parkinsonian signs was clinically associated with myoclonic movements. In each case, the parkinsonian signs were relatively mild and myoclonus was the major abnormality. The presentation of these three unusual cases within 1 year may be coincidental or may reflect a common pathogenetic mechanism. Adrenocorticotropic hormone was given to all three patients. It ameliorated the myoclonus in two patients but had no effect on the third.