Trontelj J V, Stålberg E
University Institute of Clinical Neurophysiology, University Medical Center, Ljubljana, Yugoslavia.
Muscle Nerve. 1991 Mar;14(3):226-32. doi: 10.1002/mus.880140305.
The jitter and frequency of blocking was studied at single motor end-plates in 10 patients with myasthenia gravis (MG) and in a patient with Lambert-Eaton myasthenic syndrome (LEMS), using single fiber EMG (SFEMG) with axonal microstimulation at rates varying from 0.5 Hz to 20 Hz. While some myasthenic motor end-plates showed lowest degrees of transmission disturbance at the lowest rates and most pronounced abnormality at the highest rates of stimulation, over one-half were most abnormal at intermediate rates and improved at higher rates. In 1 patient, all end-plates behaved in this way. On the other hand, all end-plates in the LEMS patient showed the expected improvement of the abnormal jitter and blocking on increasing the stimulation rate. It is argued that improvement of jitter and blocking at higher rates, unless dramatic, does not necessarily suggest a presynaptic abnormality.
采用单纤维肌电图（SFEMG）并以0.5Hz至20Hz的不同频率进行轴突微刺激，研究了10例重症肌无力（MG）患者和1例兰伯特-伊顿肌无力综合征（LEMS）患者单个运动终板的颤抖和阻滞频率。虽然一些重症肌无力运动终板在最低刺激频率时传递干扰程度最低，而在最高刺激频率时异常最明显，但超过一半的终板在中等刺激频率时异常最严重，而在更高刺激频率时有所改善。在1例患者中，所有终板均表现如此。另一方面，LEMS患者的所有终板在增加刺激频率时，异常颤抖和阻滞均呈现预期的改善。有人认为，除非改善明显，否则较高刺激频率下颤抖和阻滞的改善不一定提示突触前异常。
