Twenty-five cases from the literature and four personal cases with dystonia musculorum deformans are described. The polysomnographic EEG findings of severely involved patients were characterized by over abundance of stage 2 sleep, with a characteristic pattern of spindle activity, increased latency to sleep, and reduced sleep efficiency. The similarities between these patients may underscore the importance of sleep spindles as a feature of the dystonia process and may be useful in the investigation of other basal ganglia disorders.