Changes in sympathetic tone associated with different forms of transcutaneous electrical nerve stimulation in healthy subjects.

The purpose of this study was to determine the effect of four different forms of transcutaneous electrical nerve stimulation (TENS) on sympathetic tone in healthy subjects. Twelve subjects received high frequency, low frequency, burst frequency, and placebo stimulation to one upper extremity. Treatments were given on different days. Ipsilateral and contralateral fingertip skin temperatures were measured at three intervals for each treatment: 1) after a 25-minute rest period before stimulation, 2) after a 25-minute treatment, and 3) 25-minutes posttreatment. High, low, and burst frequency TENS significantly increased sympathetic activity in the ipsilateral extremity immediately after treatment. Similar trends in temperature change were seen on the contralateral side. The effects of the three nonplacebo treatments did not differ from each other. Further research is needed to assess sympathetic effects of TENS on patient groups. The results suggest that monitoring skin temperature as part of a TENS assessment may be warranted, especially in patients with distal vascular impairments.