查看文章

We studied 137 ulnar nerves and abductor digiti minimi (ADM) muscles in 70 patients with amyotrophic lateral sclerosis (ALS), and correlated the results with ADM strength graded on the Medical Research Council (MRC) scale, to address the potential value of a standardized neurophysiological assessment of this nerve–muscle system. The ulnar nerves of 35 normal subjects matched for age, gender, and height served as controls. Reduced compound muscle action potential (CMAP) amplitude and area in the ADM muscle recordings correlated strongly with weakness. Distal motor latency, proximal conduction time, and F‐wave frequency were abnormal with minimally detectable weakness. In weaker ADM muscles, conduction velocities and F‐wave latencies were also abnormal. Conduction block was never observed and sensory potentials were normal. An “ALS neurophysiological index” was derived from these …