Effect of repetitive transcranial magnetic stimulation on action myoclonus: A pilot study in patients with EPM1.

OBJECTIVE: The objective of this study was to explore the short-term effects of repetitive transcranial magnetic stimulation (rTMS) on action myoclonus. METHODS: Nine patients with Unverricht-Lundborg (EPM1) progressive myoclonus epilepsy type underwent two series of 500 stimuli at 0.3Hz through round coil twice a day for five consecutive days. Clinical and neurophysiological examinations were performed two hours before starting the first rTMS session and two hours after the end of the last rTMS session. RESULTS: Eight patients completed the protocol; one discontinued because of a transient increase in spontaneous jerks. The unified myoclonus rating scale indicated a 25% reduction in posttreatment myoclonus with action score associated with an increase in the cortical motor threshold and lengthening of the cortical silent period (CSP). The decrease in the myoclonus with action scores correlated with the prolongation of CSP. CONCLUSIONS: Repetitive transcranial magnetic stimulation can be safely used in patients with EPM1, improves action myoclonus, and partially restores deficient cortical inhibition.