Chan R C, Yang T F, Penn I W, Chuang T Y
Department of Physical Medicine and Rehabilitation, National Yang-Ming University School of Medicine, Taiwan ROC.
Electromyogr Clin Neurophysiol. 1998 Jul-Aug;38(5):317-20.
Lesions of mixed peripheral nerves are often diagnosed by means of electrodiagnostic tests, especially by motor and sensory conduction studies. In order to clarify the varying degrees of motor nerve involvement in patients with carpal tunnel syndrome (CTS), we designed this study for comparing the results of compound muscle action potential (CMAP) amplitude and area under the negative phase between normal persons (n = 662) and patients having CTS (n = 250). The CTS cases were categorized into two distinct groups, i.e., CTS-D (n = 120) having prolonged median sensory latency and normal needle examination, CTS-AD having prolonged median sensory latency and abnormal needle findings (n = 130). Subjects in the CTS-AD group showed significant reduction, both in CMAP amplitude and area from 3rd to 7th decades; however, in the CTS-D group there were significantly smaller CMAP amplitude from 5th to 7th decades but CMAP area demonstrated wide variations. These data indicate that CMAP amplitude and area are helpful in documenting motor nerve axonal loss, but care must be exercised when attempt is made to define axonal loss based either on area or amplitude because of the temporal dispersive effects.
混合性周围神经损伤常通过电诊断测试来诊断，尤其是通过运动和感觉传导研究。为了阐明腕管综合征（CTS）患者运动神经受累的不同程度，我们设计了本研究，以比较正常人（n = 662）和CTS患者（n = 250）的复合肌肉动作电位（CMAP）幅度和负相下面积的结果。CTS病例分为两个不同的组，即CTS-D组（n = 120），其正中感觉潜伏期延长且针极检查正常；CTS-AD组，其正中感觉潜伏期延长且针极检查异常（n = 130）。CTS-AD组的受试者在30岁至70岁之间，CMAP幅度和面积均显著降低；然而，CTS-D组在50岁至70岁之间CMAP幅度显著较小，但CMAP面积显示出广泛差异。这些数据表明，CMAP幅度和面积有助于记录运动神经轴突损失，但由于时间离散效应，在试图根据面积或幅度定义轴突损失时必须谨慎。
