Spontaneous temporal changes and variability of peripheral nerve conduction analyzed using a random effects model.

Abstract

The reproducibility of variables commonly included in studies of peripheral nerve conduction in healthy individuals has not previously been analyzed using a random effects regression model. We examined the temporal changes and variability of standard nerve conduction measures in the leg. Peroneal nerve distal motor latency, motor conduction velocity, and compound motor action potential amplitude; sural nerve sensory action potential amplitude and sensory conduction velocity; and tibial nerve minimal F-wave latency were examined in 51 healthy subjects, aged 40 to 67 years. They were reexamined after 2 and 26 weeks. There was no change in the variables except for a minor decrease in sural nerve sensory action potential amplitude and a minor increase in tibial nerve minimal F-wave latency. Reproducibility was best for peroneal nerve distal motor latency and motor conduction velocity, sural nerve sensory conduction velocity, and tibial nerve minimal F-wave latency. Between-subject variability was greater than within-subject variability. Sample sizes ranging from 21 to 128 would be required to show changes twice the magnitude of the spontaneous changes observed in this study. Nerve conduction studies have a high reproducibility, and variables are mainly unaltered during 6 months. This study provides a solid basis for the planning of future clinical trials assessing changes in nerve conduction.