[Negative myoclonus]

Abstract

Negative myoclonus is an involuntary movement produced by a short interruption of muscle contraction. In this paper, recent concepts, pathomechanisms and treatment in negative myoclonus are reviewed. Two patients with negative myoclonus are also presented. One is an 18-year-old girl with Gaucher disease, and the other is a 14-year-old boy with simple partial motor epilepsy. Electrical silent period was demonstrated when negative myoclonus was clinically observed. In both patients, somatosensory evoked potentials showed giant responses, which may indicate that mechanisms of negative myoclonus have a relationship with cortical abnormal excitability.