Effect of different TENS stimulus parameters on ulnar motor nerve conduction velocity.

The purpose of this study was to determine the effect of different TENS stimulus characteristics on ulnar motor nerve conduction velocity (MNCV) in the forearm and on forearm and ring finger skin temperatures. Thirty-one healthy women consented to receive conventional, acupuncture-like and placebo TENS: one treatment being randomly administered on each of 3 separate days within 1 week. No significant difference in MNCV (m/s) was observed between the three treatments at any of the six times of measurement (P > 0.05). Post-treatment MNCVs were, however, significantly slower than pretreatment velocities (time main effect; P < 0.01), although the differences were only about 3% in magnitude. No significant differences in finger or in forearm skin temperature were observed between the three treatments at any of the six times of measurement (P > 0.05). However, forearm skin temperatures were significantly higher than were ring finger skin temperatures, and only finger temperature changed over time (site x time interaction; P < 0.01). The small changes in MNCV and finger skin temperature were attributed to subject inactivity during testing. Acupuncture-like and conventional TENS do not have different or unique effects on motor nerve conduction velocity when applied at clinical levels of stimulus intensity.