Transcutaneous electrical nerve stimulation(TENS) is a well established clinical technique to alleviate acute & chronic pain. However, its mechanism of action remains unknown and the stimulation parameters used are based on subjective reports from patient.

In the present study, The analgesic effect of TENS in cold-induced pain was assesed using a range of 3 stimulating frequencies(40 Hz, 80 Hz, 100Hz) in 60 normal healthy subjects. The subjects are randomly allocated 1 of 5TENS treatment regimes; 40 Hz, 80 Hz, 100Hz, sham and control TENS. Pain threshold and tolerance measurement were taken during 6 experimental cycles each lasting 15 min. Two pre-treatment cycles were followed by 4 treatment cycles.

TENS significantly elevated cold-induced pail threshold & tolerance when compared with sham and control groups. There is no significant difference in pain tolerance between different frequencies, but significant relationship in pain threshold between 40Hz & 100Hz.

We can conclude that TENS is effective in alleviating pain with elevation of pain threshold as well as pain tolerance.