Movement disorders in multiple sclerosis.

Movement disorders (MD), other than tremor, associated with multiple sclerosis (MS) occur infrequently. We report 14 new cases of whom nine had dystonia, three parkinsonism, and two had myoclonus. We also reviewed 135 such cases from the literature. From an analysis of the individual MDs and the site of the lesions described, we conclude that paroxysmal dystonias (tonic spasms), ballism/chorea, and palatal myoclonus can be caused by demyelinating lesions. Parkinsonism, dystonia, and other types of myoclonus, however, often appear to be coincidental.