Dengler R, Konstanzer A, Küther G, Hesse S, Wolf W, Struppler A
Department of Neurology, Technical University of Munich, FRG.
Muscle Nerve. 1990 Jun;13(6):545-50. doi: 10.1002/mus.880130612.
Macro-EMG potentials (MEP)s and twitch contractions (spike-triggered-averaging) of single motor units (MUs) have been recorded in the first dorsal interosseus muscle (FDI) of 10 control subjects and 20 patients with amyotrophic lateral sclerosis (ALS). MUs over the full range of voluntary recruitment thresholds were studied. Patients with slightly affected FDIs (5) mainly showed MUs with enlarged MEPs and increased twitch forces. In contrast, the patients with more severely affected FDIs (15) revealed decreased twitch forces, especially in the MUs with higher thresholds. The corresponding MEPs could be enlarged as well as normal. It appears that MU sprouting and the resulting increase of twitch force can compensate for the loss of motoneuron in early stages of ALS. In more advanced stages, however, a decline of the force of the surviving MUs, especially of those with higher thresholds, seems to contribute to the progressive muscle weakness, in addition to the corticospinal degeneration and the reduction in the number of motoneurons.
在10名对照受试者和20例肌萎缩侧索硬化症（ALS）患者的第一背侧骨间肌（FDI）中记录了单个运动单位（MU）的宏肌电图电位（MEP）和抽搐收缩（触发尖峰平均）。研究了自愿募集阈值全范围内的运动单位。轻度受影响的FDI患者（5例）主要表现为MEP增大和抽搐力增加的运动单位。相比之下，受影响更严重的FDI患者（15例）显示抽搐力下降，尤其是阈值较高的运动单位。相应的MEP可能增大也可能正常。似乎在ALS早期，运动单位芽生以及由此导致的抽搐力增加可以补偿运动神经元的损失。然而，在更晚期阶段，除了皮质脊髓变性和运动神经元数量减少外，存活运动单位的力量下降，尤其是阈值较高的运动单位，似乎导致了进行性肌肉无力。
