An Investigation Into the Effect of Electrode Placement of Transcutaneous Electrical Nerve Stimulation (TENS) on Experimentally Induced Ischemic Pain in Healthy Human Participants

Abstract

It is claimed that transcutaneous electrical nerve stimulation (TENS) operates via a segmental mechanism by reducing ongoing transmission and sensitization of nociceptive dorsal horn neurons. Hence, TENS electrodes are usually placed at the site of pain. This study compared TENS administered at the site of experimentally induced ischemic pain (ipsilateral forearm) with TENS administered at a location not related to pain (contralateral lower leg). Ten healthy, pain free volunteers took part in a cross-over study during which ischemic pain was induced in the nondominant arm using a modified version of submaximal effort tourniquet technique. Pain intensity was taken at 1-minute interval/s for 5 minutes while receiving TENS either at the ipsilateral arm or contralateral leg. There were no statistically significant differences in pain intensity or McGill Pain Questionnaire ratings between TENS given at the arm compared with the leg. Taken at face value, the findings suggest that TENS effects were nonspecific and that electrode location does not affect outcome. However, this study should be seen as a call for further research rather than a definitive conclusion.