Syndrome of palatal myoclonus and progressive ataxia: two cases with magnetic resonance imaging.

Two patients are reported with palatal myoclonus, progressive ataxia, and dysarthria, unresponsive to treatment with trihexyphenidyl or L-5-hydroxytryptophan. MRI showed enlargement of the inferior olives in one patient, consistent with the pathology usually associated with palatal myoclonus. The syndrome of progressive ataxia and palatal myoclonus should be distinguished from other ataxias and degenerations that affect the brainstem and cerebellum. Pathology and specificity of site of the lesions are distinctive.