Uncini A, Lange D J, Lovelace R E, Solomon M, Hays A P
Department of Clinical Neurophysiology, Columbia University College of Physicians and Surgeons, New York, NY.
Muscle Nerve. 1990 Mar;13(3):263-7. doi: 10.1002/mus.880130315.
In most myopathies, the duration of motor unit action potentials (MUAPs) is shorter than normal. However, polyphasic MUAPs of duration longer than 20% of the control mean, (long-duration polyphasic potentials, or LDPPs) may be seen. We therefore analyzed the incidence and meaning of LDPPs using quantitative MUAP analysis in 41 patients with different myopathies. The mean duration of all potentials was reduced in only 64% of patients because LDPPs increased the mean. When only simple potentials were considered, however, the mean duration was decreased in 95% of patients. This observation confirms the need to exclude LDPPs when calculating the mean duration of MUAPs for diagnosis. We found LDPPs most often in chronic polymyositis and in one patient with Becker Muscular Dystrophy. LDPPs are attributed to desynchronization of single-fiber potentials within the MUAP and may be due to slow conduction in regenerating muscle fibers.
在大多数肌病中，运动单位动作电位（MUAPs）的时限短于正常。然而，可能会出现时限比对照平均值长20%以上的多相MUAPs（长时间多相电位，或LDPPs）。因此，我们使用定量MUAP分析对41例不同肌病患者的LDPPs发生率及意义进行了分析。由于LDPPs使平均值升高，仅64%的患者所有电位的平均时限降低。然而，若仅考虑单纯电位，95%的患者平均时限降低。该观察结果证实，在计算MUAPs平均时限以进行诊断时，有必要排除LDPPs。我们发现LDPPs最常出现于慢性多发性肌炎以及1例贝克型肌营养不良患者中。LDPPs归因于MUAP内单纤维电位的不同步，可能是由于再生肌纤维中传导缓慢所致。
