Pudendal nerve motor latency correlation by age and sex.

This study was a prospective study, it was undertaken on 172 subjects who had no prior central or peripheral nerve supply pathology and who had not an antecedent of anal surgery. The subjects had a normal value of the sacral reflex latency to be included in this study. In this population the value of the pudendal motor nerve latency was compared by age and sex in order to determine precise norms. There was 92 men whose age adveraged 36 +/- 14.57 years and 80 women with an average age of 55.03 +/- 15.7. The motor latency was obtained by stimulating the nerve by rectal or vaginal tuch-near the sciatic spine with a St Mark's electrod and taking a reading in the intemediate part of the external anal sphincter muscle. The intensity of the stimulation was 70 to 80 mA. The stimulation and the recording was repeteded five both on each side and the shorter latency whose choised. The value of the motor latency taken at the positive peak was analysed statiscally. The average value was 5.52 +/- 1.9 ms on right pudendal nerve and 5.74 +/- 1.6 ms on the left in male subjects and 6.16 +/- 1.8 in the right pudendal nerve and 6.42 +/- 1.96 on the left in female subjects. The values on right pudendal nerve latency varied from 4.9 +/- 1.28 ms in men and 4.76 +/- 1.6 ms. in women at under 28 years and to 5.06 +/- 2.06 ms in men and 7.7 +/- 1.8 ms in women at over 70 years. The values on the left side varied from 5.53 +/- 1.5 ms in men and 4.78 +/- 1.35 ms in women at under 28 years and to 5.06 +/- 2.06 ms in men and 8.47 +/- 1.95 ms in women at over 70 years. In men population, the value of the motor latency of the pudendal nerve is not correlated with age. In women population, the value is correlated with age.