Rubboli G, Tassinari C A
Neurology Unit, Department of Neurosciences, Bellaria Hospital, University of Bologna, Via Altura, 3-40139 Bologna, Italy.
Neurophysiol Clin. 2006 Sep-Dec;36(5-6):337-43. doi: 10.1016/j.neucli.2006.12.001. Epub 2007 Jan 23.
Negative myoclonus (NM) is an unspecific motor disorder that can characterize a variety of neurological conditions. From the clinical point of view, NM appears as a shock-like involuntary jerky movement caused by a sudden, brief interruption of muscle activity. Asterixis is a type of NM that occurs typically in toxic-metabolic encephalopathies. NM of epileptic nature, or epileptic negative myoclonus (ENM), is defined as an interruption of tonic muscle activity, which is time-locked to an epileptic EEG abnormality, without evidence of an antecedent positive myoclonia in the agonist-antagonist muscles. ENM can be observed in idiopathic, cryptogenic, and symptomatic epileptic disorders. Pathophysiological hypotheses on the origin of NM involve subcortical as well as cortical mechanisms. Recent neuroimaging and neurophysiologic investigations, including intracerebral recordings and electrical stimulation procedures in epileptic patients, suggest the participation of premotor, primary motor, primary sensory, and supplementary motor areas in the genesis of NM. Polygraphic monitoring is essential for the diagnosis of NM, allowing the demonstration of brief interruptions of a tonic EMG activity, not preceded by a positive myoclonus in the agonist and antagonist muscles of the affected limb. Simultaneous EEG-EMG monitoring demonstrating the association of NM with an epileptic potential is consistent with the diagnosis of ENM. Evolution and prognosis of NM is mainly related to aetiology. In childhood idiopathic partial epilepsy, ENM can respond to some drugs (in particular, ethosuximide), whereas other medications (such as carbamazepine or phenytoin) have been reported to induce or worsen it.
负性肌阵挛（NM）是一种非特异性运动障碍，可表现为多种神经疾病的特征。从临床角度来看，NM表现为肌肉活动突然短暂中断引起的类似电击的不自主抽搐运动。扑翼样震颤是一种通常发生在中毒代谢性脑病中的NM类型。癫痫性负性肌阵挛（ENM），即癫痫性质的NM，被定义为紧张性肌肉活动的中断，与癫痫性脑电图异常时间锁定，且在主动肌-拮抗肌中无前驱性正性肌阵挛的证据。ENM可见于特发性、隐源性和症状性癫痫疾病。关于NM起源的病理生理假说是皮质下和皮质机制均有涉及。最近的神经影像学和神经生理学研究，包括癫痫患者的脑内记录和电刺激程序，提示运动前区、初级运动区、初级感觉区和辅助运动区参与了NM的发生。多导监测对于NM的诊断至关重要，可显示紧张性肌电图活动的短暂中断，且在受影响肢体的主动肌和拮抗肌中无正性肌阵挛前驱。同步脑电图-肌电图监测显示NM与癫痫电位相关，这与ENM的诊断一致。NM的演变和预后主要与病因有关。在儿童特发性部分性癫痫中，ENM可能对某些药物（特别是乙琥胺）有反应，而据报道其他药物（如卡马西平或苯妥英）可诱发或加重ENM。
