We studied electronic averaging technique of F wave in the median nerves of normal volunteers to get most appropriate numbers of averaging and to determine the amount of cancellation effects of amplitudes and areas of averaged F waves and to get normal data about averaged median nerve F wave latency and amplitude.

To determine the most reasonable numbers of averaging, we studied 10, 20 and 50 numbers of averaging in bilateral median nerves of 20 volunteers. There was on statistically significant differences of latency, amplitude, and negative area among 10, 20 and 50 numbers of averaging. But there was decreasing tendency, amplitude and negative area and increasing tendency in reproducibillity and cancellation effect as increasing numbers of averaging. Considering about more information with less discomfort and study time, we determined 10 and 20 numbers of averaging to be adequate. And the latency and amplitude of averaged F waves could be considered as useful clinical parameters.

We concluded that 10 and 20 averaged F waves in human were convenient, reproducible, and deviated little due to cancellation effect.