McComas A J, Campbell M J, Sica R E
J Neurol Neurosurg Psychiatry. 1971 Apr;34(2):132-9.
A comprehensive electrophysiological study has been made of the extensor digitorum brevis muscle and its motor innervation in 17 patients with dystrophia myotonica. The mean contraction and half-relaxation times were prolonged in the isometric twitches of dystrophic muscles. Decremental responses to repetitive motor nerve stimulation were found in two patients. All the terminal latency measurements were normal and only one patient had a reduced nerve conduction velocity. As the patients aged their muscles became weaker, due to a progressive loss of motor units. This finding, and the normal sizes of many surviving motor units, suggested that the muscle changes resulted from a primary defect of motor innervation.
对17例强直性肌营养不良患者的趾短伸肌及其运动神经支配进行了全面的电生理研究。营养不良肌肉的等长收缩时，平均收缩时间和半松弛时间延长。在2例患者中发现对重复运动神经刺激的递减反应。所有终末潜伏期测量均正常，只有1例患者神经传导速度降低。随着患者年龄增长，由于运动单位逐渐丧失，其肌肉变得更弱。这一发现以及许多存活运动单位的正常大小表明，肌肉变化是由运动神经支配的原发性缺陷引起的。
