Ulnar Nerve F-Wave Latencies Recorded From the Abductor Digiti Minimi1

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 (Fmin), mean F-wave (Fmean), the number of F-waves present out of ten stimuli (Fpersist), and the range of latencies (Frange). An analysis of variance statistical procedure was applied, and the Fmin and Fmean were found to correlate with age, gender, and height, although the gender effect was relatively weak. For all subjects taken together, the mean Fmin was 26.5 +/- 2.5 ms. The Fmean was 27.7 +/- 2.5 ms, and the mean Frange was 2.6 +/- 1.2 ms. Ninety-seven percent of subjects had an Fpersist of five or more. Mean side-to-side difference for Fmin was 0.2 +/- 1.1 ms.