Noachtar S, Holthausen H, Lüders H O
Department of Neurology, University of Munich, Germany.
Neurology. 1997 Dec;49(6):1534-7. doi: 10.1212/wnl.49.6.1534.
We report a patient with epileptic negative myoclonus (ENM) presenting as status epilepticus of the right arm. The etiology was a cortical malformation in the contralateral postcentral gyrus. Electrical stimulation of the right median nerve revealed giant surface somatosensory evoked potentials. Subdural recordings, performed to plan epilepsy surgery, demonstrated that the epileptogenic zone was in the left postcentral gyrus. Repetitive left postcentral spikes were consistently followed by an EMG silent period in the right arm with a latency of about 20 to 30 msec. The silent period in the EMG reflected the negative myoclonus and lasted 30 to 340 msec, mostly between 100 and 200 msec. Spikes in other regions of the cortex did not elicit ENM. The amplitude and duration of the spikes correlated with the EMG silent period: the more cortex involved in the spike generation, the longer the duration of the silent period. This suggests that epileptic activation of postcentral cortex leads to an inhibition of tonic activity of motor neurons. Focal ENM may be related to a hyperexcitability of the postcentral cortex.
我们报告了一名患有癫痫性负性肌阵挛（ENM）的患者，其表现为右臂癫痫持续状态。病因是对侧中央后回的皮质发育畸形。对右侧正中神经进行电刺激显示出巨大的表面体感诱发电位。为计划癫痫手术而进行的硬膜下记录表明，致痫区位于左侧中央后回。重复性的左侧中央后回尖波始终会在右臂引发肌电图静息期，潜伏期约为20至30毫秒。肌电图中的静息期反映了负性肌阵挛，持续30至340毫秒，大多在100至200毫秒之间。皮质其他区域的尖波未引发ENM。尖波的幅度和持续时间与肌电图静息期相关：参与尖波产生的皮质区域越多，静息期持续时间越长。这表明中央后皮质的癫痫激活会导致运动神经元紧张性活动受到抑制。局灶性ENM可能与中央后皮质的过度兴奋性有关。
