多点刺激法进行运动单位数目估计及其正常值探讨

Reference range for motor unit number estimation by multiple point stimulation

目的采用多点刺激法进行运动单位数目估计（MUNE）检测，并探寻其国人正常值。方法对知情同意的80名健康志愿者进行多点刺激法MUNE：刺激电极分别于腕、腕上6cm、肘、肘上6cm共4点刺激正中神经或尺神经，以超强刺激诱发最大波幅M波，然后从0mA刺激开始逐渐增加刺激强度，直到出现可辨认的低波幅的单个运动单位电位，稳定后保存，每次记录3个递增的M波，再逐渐增大刺激强度，共获取12个递增的M波。重复做2次。结果健康志愿者拇短展肌MUNE结果为230．0±35．7，小指展肌242．5±30．2。多点刺激法2次测验所得的MUNE的相关系数为0．88～0．91，变异系数13．20％～15．24％，差异无统计学意义。结论多点刺激法能测定运动单位数目，可重复性良好。

Objective To examine the technique of multiple point stimulation for motor unit number estimation （MUNE） and to establish the normative value range in Chinese. Methods Surface-recorded motor unit action potentials were measured in 80 healthy subjects. The compound muscle action potential （CMAP） amplitude measured by maximum baseline to negative peak was recorded. The stimuli sites included the wrist, 6 cm above the wrist, elbow and 6 cm above the elbow along median nerve and ulnar nerve. Individual motor unit responses were obtained by adjusting location of the stimulate electrode and isolating threshold responses with distinct morphologies. Then, stimulus intensity was increased gradually to detect single motor unit action potentials （SMUPs）. SMUPs were recorded three times. Stimulating was increase again to record another SMUPs set. Total of 12 SMUPs were recorded. Repeat the whole procedure for two times. Results MUNE was 230. 0 ± 35.7 in abductor pollicis brevis muscle, and 242. 5 ± 30. 2 in aductor digiti minimi muscle for multiple point stimulation. Test-retest correlation coefficients and coefficients of variation for mean of two MUNE were 0. 88--0. 91 and 13.20%--15.24%. Conclusions The multiple point stimulation is a useful and replicable method to asses the MUNE.