Effect of gender on orthodromic sensory nerve action potential amplitude

OBJECTIVE: Studies in the literature have demonstrated a gender effect on sensory nerve action potential (SNAP) amplitude for the median and ulnar nerves by use of the antidromic method of recording. The objective of this study was to determine if performing orthodromic sensory nerve stimulation eliminates the gender bias by removing the finger circumference as a variable. METHODS: Fifty-five healthy subjects participated in the study. The mean age of the subjects was 37.8 +/- 5.9 yr and 35.3 +/- 5.9 yr for men and women, respectively. Orthodromic sensory nerve conduction studies were performed for the median and ulnar nerves measuring the SNAP amplitude by use of standard electrophysiologic technique. RESULTS: The mean finger circumference of the third digit was 6.5 +/- 0.58 cm for men and 5.9 +/- 0.47 cm for women, and for the fifth digit, it was 5.6 +/- 0.41 cm for men and 5.3 +/- 0.37 cm for women. The median SNAP amplitude and their percentiles of 2.5 and 97.5 for the median nerve were 30.0 microV for men and 28.0 microV for women. For the ulnar nerve, they were 16.5 microV for men and 16.0 microV for women. CONCLUSION: The study confirmed that orthodromic sensory nerve stimulation did not have any significant effect on SNAP amplitude between men and women.