Intra-examiner reliability of sensory nerve conduction measurements.

The objective of this study was to investigate the intra-examiner reliability of consecutive sensory nerve action potential amplitude measurements with short time intervals. Amplitudes were compared in repeated sensory nerve action potential recordings of the lateral antebrachial cutaneous nerve on 63 healthy subjects. There were two sets of each two consecutive measurements, each set separated by a controlled interval of 90 minutes. Intraclass correlation coefficients were 0.996 and 0.998 for consecutive measurements, and 0.919 and 0.926 for measurements before and after a controlled interval of 90 minutes. The presented research clarifies the difference between measurement variability versus intra-subject variability and the influence on test-retest results in sensory nerve conduction measurements. This is of importance for correct interpretation of results when performing serial testing. It is demonstrated that a single tester can obtain reliable amplitude measurements of sensory nerve action potentials of the lateral antebrachial cutaneous nerve in asymptomatic subjects with surface recording electrodes. It is also proven that it is sufficient to control ambient temperature instead of limb temperature for this type of study on asymptomatic subjects.