Spinal myoclonus.

The focal involuntary muscular contractions of spinal myoclonus have been associated with neoplastic, infectious, traumatic, and degenerative lesions of the spinal cord. Four patients are described here. In two, the myoclonus is associated with severe cervical spondylitis. One patient had herpes zoster. In the fourth, a segment of thoracic spinal cord is narrow and probably atrophic. Both tetrabenazine and clonazepam were therapeutically effective.