Reproducibility of neurophysiological and myometric measurement in the ulnar nerve-abductor digiti minimi system

Reliability in strength and neurophysiological measurements is important in evaluating progression of neuromuscular diseases. No data are available on the variability of neurophysiological parameters as compared with maximal voluntary isometric contraction (MVIC) in the same muscles, in healthy subj ects. A control population of 26 healthy subjects was studied twice on diff erent days. We evaluated the reliability of neurophysiological parameters o btained from bilateral ulnar nerve stimulation, recording the response over the abductor digiti minimi (ADM) muscle, including distal motor latency, c ompound muscle potential amplitude and area, F-wave frequency and mean F-wa ve latency, and the derived neurophysiological index that we have described previously. MVIC force was measured in each session in both ADM muscles. T he variances between the grouped data obtained in the two recording session s were identical, indicating a low intrinsic variability with this experime ntal methodology. Comparison of the mean values obtained in the two session s revealed no statistically significant differences. The reliability of the se neurophysiological and strength measurements in the same nerve/muscle sy stem suggests they may be useful in comparing the dynamics of weakness and neurophysiological change in neuromuscular disease. (C) 2001 John Wiley & S ons, Inc.