Movement disorders in multiple sclerosis: Causal or coincidental association?

Despite the relatively frequent involvement of the basal ganglia and subthalamic nucleus by multiple sclerosis (MS) plaques, movement disorders (MD), other than tremor secondary to cerebellar or brainstem lesions, are uncommon clinical manifestations of MS. MD were present in 12 of 733 patients with MS (1.6%): three patients had parkinsonism, two blepharospasm, five hemifacial spasm, one hemidystonia, and one tourettism. MD in patients with MS are often secondary to demyelinating disease. Also in cases without response to steroid treatment and demyelinating lesions in critical regions, it is not possible to exclude that MD and MS are causally related.