Carpay J A, Schimsheimer R J, de Weerd A W
Department of Clinical Neurophysiology, Westeinde Hospital, The Hague, The Netherlands.
Neurophysiol Clin. 1997 Sep;27(4):309-13. doi: 10.1016/s0987-7053(97)85829-7.
Coactivation of the ulnar nerve at the wrist can be a source of error in tests for carpal tunnel syndrome (CTS). We compared the effects of coactivation in two tests for CTS: the abductor pollicis brevis-distal motor latency (APB-DML) and lumbrical-interosseus-distal motor latency difference (2LI-DML). We studied 33 hands of 25 consecutive patients referred for suspected CTS. In severe CTS, when selective supramaximal stimulation of the median nerve was impossible, all APB-compound muscle action potentials (CMAP) showed abnormalities, indicating volume conduction of ulnar muscle activation. 2LI-DML in these hands led to falsely normal test results, as two identical CMAP were obtained after median and ulnar stimulation. In less severe CTS, warning signs indicating coactivation were observed in APB-DML virtually as often as in 2LI-DML. Undetected coactivation was more likely to be associated with false normal test results in 2LI-DML than in APB-DML.
腕部尺神经的共同激活可能是腕管综合征（CTS）检测中误差的一个来源。我们比较了共同激活在两种CTS检测中的影响：拇短展肌-远端运动潜伏期（APB-DML）和蚓状肌-骨间肌-远端运动潜伏期差异（2LI-DML）。我们研究了25例因疑似CTS而转诊的连续患者的33只手。在严重的CTS中，当无法对正中神经进行选择性超强刺激时，所有APB复合肌肉动作电位（CMAP）均显示异常，提示尺侧肌肉激活的容积传导。这些手中的2LI-DML导致测试结果错误地正常，因为在正中神经和尺神经刺激后获得了两个相同的CMAP。在不太严重的CTS中，APB-DML中观察到的提示共同激活的警示信号几乎与2LI-DML中一样频繁。与APB-DML相比，未检测到的共同激活更有可能与2LI-DML中的错误正常测试结果相关。
