[Determination of the variation in conduction speed of motor fibers and the effects of diphenylhydantoin (Phenytoin) and diazepam (Faustan)].

The variation in the speed of conduction of motor fibers of the ulnar nerve was determined by Hopf's double-stimulus method and compared with values obtained from the duration of muscular response potentials for differently spaced points of stimulation. However, the values obtained from the difference of the duration of response potentials are inadequate since the duration of potentials cannot always be determined accurately. After a ten-day administration of faustan (15 mg per day) or phenytoin (300 mg per day) there was observed a decrease especially in the minimum rate of conduction of motor fibers of the ulnar nerve.