Guiloff R J, Modarres-Sadeghi H
Department of Neurology, Charing Cross and Westminster Medical School, Westminster Hospital, London, UK.
Ann Neurol. 1992 Apr;31(4):416-24. doi: 10.1002/ana.410310411.
Two hundred voluntarily activated motor units and 211 fasciculations were recorded in the biceps of 10 patients with motor neuron disease with the Macro EMG technique. Twenty-two fasciculations, in nine of 10 muscles, had a potential of closely similar shape, amplitude, and area to that of a voluntary unit. Fasciculating units that could not be activated voluntarily had a higher mean number of spikes in their triggering single fiber potentials than units that could only be activated voluntarily, but statistically similar Macro EMG parameters. The mean number of single fiber spikes, and Macro EMG parameters, of fasciculations activated voluntarily, were similar to those of units that were only activated voluntarily. A positive correlation between fiber density and Macro EMG median amplitude and area in individual patients, and between number of single fiber spikes and Macro EMG amplitudes and areas in the pooled data, was found for fasciculations but not for voluntary units. At least 10% of fasciculations in patients with motor neuron disease may originate near or above the point of axonal branching and a proportion of those without evidence of voluntary activation may have a higher number of smaller muscle fibers, or more closely packed muscle fibers, of similar or greater size, than voluntarily activated motor units. Differences in the peripheral microanatomy of a number of fasciculation units not activated voluntarily may underlie ectopic impulse generation in the terminal axonal arborization, endplate zone, or muscle fibers of these units.
采用巨肌电图技术，在10例运动神经元病患者的肱二头肌中记录到200个自发激活的运动单位和211次肌束震颤。在10块肌肉中的9块里，有22次肌束震颤的电位在形状、幅度和面积上与一个自发运动单位的电位极为相似。与只能自发激活的单位相比，无法自发激活的肌束震颤单位在触发单纤维电位时的平均棘波数量更多，但肌电图参数在统计学上相似。自发激活的肌束震颤的单纤维棘波平均数量和肌电图参数，与仅能自发激活的单位相似。在个体患者中，发现肌束震颤的纤维密度与肌电图中位幅度和面积之间存在正相关，在汇总数据中，单纤维棘波数量与肌电图幅度和面积之间也存在正相关，但自发运动单位不存在这种情况。运动神经元病患者中至少10%的肌束震颤可能起源于轴突分支点附近或上方，并且一部分没有自发激活证据的肌束震颤可能比自发激活的运动单位拥有更多数量的较小肌纤维，或者有更多紧密排列的、大小相似或更大的肌纤维。一些未自发激活的肌束震颤单位的外周微观解剖结构差异，可能是这些单位的终末轴突分支、终板区或肌纤维中异位冲动产生的基础。
