Whether the immediate pain-relief effect of transcutaneous electrical nerve stimulation (TENS) performed at the motor-level varies with the combination of frequency and pulse width

Abstract

[Purpose] The purpose of this study was to verify whether the immediate pain relief effect of motor-level Transcutaneous Electrical Nerve Stimulation (TENS) changes with the combination of frequency and pulse width. [Participants and Methods] Sixteen healthy volunteers participated in seven experimental sessions (six motor-level TENS sessions with different combinations of frequency and pulse width and a control session) across seven days. TENS was performed on electrically-induced artificial pain. The pain relief effects immediately after TENS and control were compared using a Numerical Rating Scale (NRS) and oxyhemoglobin concentration in the prefrontal cortex (Fp-HbO2). [Results] NRS and Fp-HbO2 findings showed that the pain relief effects of all the TENS sessions were significantly better than that of the control session, even though there were no significant differences in NRS and Fp-HbO2 among the TENS sessions. [Conclusion] The results suggest that the immediate pain relief effect of motor-level TENS is not impacted by the combination of frequency and pulse width.