COMPARISON OF 2 TECHNIQUES TO MEASURE THE MOTOR-NERVE REFRACTORY PERIOD DISTRIBUTION

The techniques introduced by Ingram ct al. and by Kimura to assess the motor nerve refractory period distribution were compared in the peron eal nerve of 28 healthy subjects. Twenty of these subjects were examin ed twice with an interval of 6-20 days. Results obtained with Ingram's technique yielded a narrower refractory period distribution, displaye d less inter-individual variability, and were more reproducible than t hose obtained with Kimura's technique. The mean refractory period for the 5% slowest recovering fibres (MRP(95)) was 1.51 msec (S.D. 0.14) f or Ingram's technique and 2.15 msec (S.D. 0.72) for Kimura's technique . The coefficient of variation of the MRP(95) was 8% for Ingram's tech nique, and 22% for Kimura's technique. The present data do not allow a definite conclusion concerning the association of refractory period w ith age, gender and height. Ingram's technique would be favoured for p ractical application over Kimura's technique on the basis of this stud y.