肌阵挛患儿神经电生理的临床研究

Polyneuroelectrophysiological studies of myoclonus in children

目的借助多项神经电生理技术观测不同起源和不同性质肌阵挛的临床一电生理特征。方法应用视频脑电-肌电多导记录（VEEG-EMG）、抽搐逆向锁定的脑电平均技术（jerk-locked back averaging，JLA）以及短潜伏期躯体感觉诱发电位（SSEP），对32例肌阵挛发作患儿进行临床和多项电生理的实时联合分析及分类。结果32例患儿的年龄为1个月～16岁，平均2．8岁，其中皮层性和皮层下性起源各14例，其他肌阵挛4例。（1）皮层性起源组：14例中1l例主要表现局灶性或多灶性肌阵挛，3例还同时有全身性肌阵挛发作。11例呈非节律性，3例伴节律性肌阵挛。10例肌阵挛对声响、闪光或叩击肌腱等刺激异常敏感。肌阵挛同步EMG时程为10～52ms。发作间期脑电图（EEG）有局灶、多灶、或全部性棘一慢波，或高度失律等多种异常。发作期EEG8例可见全部性l一4Hz（多）棘一慢波暴发，1例为多灶性1～2．5Hz棘-慢波，1例无明显改变，其余4例部分肌阵挛发作伴有全部性2～3Hz棘一慢波。JLA分析13例存在与肌阵挛相关的棘波，1例正常。10例SSEP检测中3例存在巨大皮层反应电位。（2）皮层下起源组：14例中8例为全身性，另6例伴多灶性肌阵挛发作，均为非节律性。对各种感觉刺激皆不敏感。同步EMG时程60～400ms。间期EEG无恒定异常，包括背景活动正常6例，伴痫性放电者8例。9例发作期EEG无明显改变，5例部分肌阵挛发作期伴痫性放电。JLA分析12例无异常，2例虽有叠加后棘波，但与肌阵挛发作无锁时关系。14例SSEP皆正常。（3）未能确认起源组：同步EMG时程60—400ms，EEG及SSEP均正常。根据多项电生理检测结果，确认本组32例患儿中，14例为癫瘌性肌阵挛。结论（1）对肌阵挛发作及其性质的判定不能仅靠发作问期和发作期EEG；（2）借助多项神经电生理技术，尤其JLA分析，能较好区分不同起源肌阵挛并确认肌阵挛的癫疴性质。

Objective To explore the clinical and neuroelectrophysiological characteristics of myoclonus of different origins in children. Method Thirty-two children with myoelonic seizure were analyzed by video electroencephalogram-electromyogram （VEEG-EMG） polygraphic recordings, jerk-locked back averaging （JLA） and short latency somatosensory evoked potential （SSEP）. They were classified into cortical myoclonus （CM）, subcortical myoclonus （SCM）, and unidentified group according to their generating locations, and also were classified into epileptic and non-epileptic myoclonus based on their different properties. Result The 32 patients included 14 with CM, 14 with SCM and 4 with unidentified origin. （ 1 ） CM group： the myoclonic patients presented as focal and/or multifocal seizures in 11 cases and as generalized in another 3 patients besides focal myoclonus. At＇rhythmic jerks were shown completely in 11 cases and rhythmic seizures were concomitant in another 3 patients. Myoclonus sensitivity to sensory stimulus was observed in 10 patients. The durations of EMG burst were 10-52 ms. Background EEGs were presented normal in 4 patients and slowing in 10 patients. The epileptiform discharges in interictal EEG were variable. The ictal EEG showed epileptic discharges with each clinical jerk in 9 cases but only with some jerks in 4 patients. Another one had no any EEG abnormality in each jerk. The myoclonus-related spikes were disclosed in 13 cases by JLA. Of the 10 cases who underwent SSEP, giant SSEPs were seen in 3 cases including the one with normal EEG and JLA analyses. （2） SCM group： myoclonus was presented as generalized in 8 cases and as focal in 6 cases. All the patients showed arrhythmic jerks and 14 cases were not sensitive to stimulus. The durations of EMG burst were from 60 ms to 400 ms. Normal background EEGs were presented in 6 patients and slowing in 8 patients. The interictal EEG showed no consistent abnormality. Epileptic discharges associated with myoclonus seizures were not found in any of 9 patients but were observed with some seizure changes in 5 cases. There was no myoclonus-related spike by JLA in this group. SSEPs were normal in all patients. （3） The group with unidentified origin ： the durations of EMG were from 60 ms to 400 ms, and their EEG and SSEP recordings were normal. In addition, 32 patients could be classified as epileptic myoclonus in 14 cases and nonepileptic myoclonus in 18 cases by the polyneurophysiological tests. Conclusion （ 1 ） It is not reliable to identify myoclonus seizures and their clinical properties depending on their interictal and ictal EEGs only. （2） Polyneuroelectrophysiological tests, including EEG-EMG, JLA, and SSEP, seem to be valuable and useful to identify the generating locations and properties for different myoclonus in children.