Hyperkinetic mutism: bilateral ballism and basal ganglia calcification.

We studied a 70-year-old woman with a unique combination of hyperkinesia and mutism. These findings differed from akinetic mutism because there was continuous bilateral ballism and dystonia--hence the term "hyperkinetic mutism." CT demonstrated bilateral calcifications in the basal ganglia, and MRI indicated bilateral watershed infarcts. Different dopaminergic mechanisms may underlie the hyperkinesia and mutism.