Electrodiagnostic reference values for the lateral antebrachial cutaneous nerve: standardization of a 10-cm distance.

Abstract

To derive a normative database for nerve conduction values of the lateral antebrachial cutaneous nerve (LACN) using a large and varied subject population. Descriptive study. Private office or university-based clinic. Volunteers (n = 213), recruited through advertisements, who met inclusion criteria. Onset latency, peak latency, baseline-to-peak amplitude, peak-to-peak amplitude, area, rise time, duration, side-to-side differences, and the effects of age, race, sex, height, and body mass index (BMI) were investigated on 213 healthy volunteers between the ages of 19 and 79 years. The mean +/- SD onset latency was 1.7+/-0.2 ms. The 95th and 97th percentile values for onset latency were 2 and 2.1 ms, respectively. Mean peak latency was 2.2+/-0.2 ms. Both the 95th and 97th percentile values for peak latency were 2.5 ms. Mean onset to peak amplitude was 18+/-10 microV. The 5th and 3rd percentile values for onset to peak amplitude were 6 and 5 microV, respectively. Mean peak-to-peak amplitude was 22+/-15 microV. The 5th and 3rd percentile values for peak-to-peak amplitude were 7 and 6 microV, respectively. Mean area was 11+/-7nV-s, mean rise time was 0.5+/-0.1 ms, and mean duration was 1.1+/-0.2 ms. Mean side-to-side difference was 0.1+/-0.2 ms for onset latency, 0.1+/-0.2 ms for peak latency, 1+/-12 microV for onset to peak amplitude, and 0+/-17 microV for peak-to-peak amplitude. Increasing age and BMI were associated with lower mean amplitudes, but did not affect the lower limits of normal. These normative values will be useful in electrodiagnostic study of the LACN.