Pain-relief Effect of Transcutaneous Electrical Nerve Stimulation (TENS): Changes in Physiological Responses and TENS Stimulus Intensity

Abstract

[Purpose] The aim of this study was to investigate the pain-relief effect of transcutaneous electrical nerve stimulation (TENS) focusing on changes in physiological responses and TENS stimulus intensity. [Subjects and Methods] Sixteen healthy volunteers participated in this study, and received three interventions for artificially induced pain: no treatment control, and TENS at 100 Hz of high intensity (above the motor threshold), and low intensity (sensory level). The pain-relief effect of the three interventions was compared using a subjective pain rating scale (NRS) and two physiological responses: cerebral blood flow of the prefrontal cortex (PF-CBF) and sympathetic nerve activity (SNA). [Results] NRS and PF-CBF findings showed that the pain-relief effect of high intensity TENS was significantly better than that of low intensity TENS and the control. There was no significant differences in SNA among the three interventions. [Conclusion] High intensity TENS should provide an excellent pain-relief effect in terms of both subjective and physiological aspects.