Ulnar nerve F-wave latencies recorded from the abductor digiti minimi

This study was performed to create a large database of normal values for the ulnar F-wave study and to investigate the effect of various demographic factors on F-wave results. The study was designed to incorporate a standard distance measure and temperature control, which are lacking in some previous studies. One hundred ninety-three asymptomatic volunteers without risk factors for neuropathy were recruited and had ten F-waves performed on each arm. Data were collected for the shortest F-wave (F-min), mean F-wave (F-mean), the number of F-waves present out of ten stimuli (F-persist) and the range of latencies (F-range). An analysis of variance statistical procedure was applied, and the F-min and F-mean were found to correlate with age, gender, and height, although the gender effect was relatively weak, For all subjects taken together, the mean F-min was 26.5 +/- 2.5 ms. The F-mean was 27.7 +/- 2.5 ms, and the mean F-range was 2.6 +/- 1.2 ms. Ninety-seven percent of subjects had an F-persist of five or more. Mean side-to-side difference for F-min was 0.2 +/- 1.1 ms.