Myoclonus and tremor response to thalamic deep brain stimulation parameters in a patient with inherited myoclonus-dystonia syndrome.

We present a 74-year-old woman with inherited myoclonus-dystonia, with predominant myoclonus and a novel mutation in the epsilon-sarcoglycan gene. The patient reports a life-long history of rapid, jerking movements, most severe in the upper extremities as well as a postural and action tremor. Bilateral deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus was performed, and the patient demonstrated moderate clinical improvement in myoclonus. We studied the effects on myoclonus and tremor of varying DBS frequency and amplitude. The frequency tuning curve for myoclonus was similar to that of tremor, suggesting similar mechanisms by which DBS alleviates both disorders.