Analgesic effects of different frequencies of transcutaneous electrical nerve stimulation on cold-induced pain in normal subjects.

The efficacy of transcutaneous electrical nerve stimulation (TENS) in producing analgesia in cold-induced pain was assessed using a range of 5 stimulating frequencies (10 Hz, 20 Hz, 40 Hz, 80 Hz and 160 Hz) in 83 normal healthy subjects. TENS significantly elevated ice pain threshold when compared with sham and control groups. TENS frequencies between 20 and 80 Hz produced greatest analgesia, while frequencies below and above this level (10 Hz and 160 Hz), although significantly elevating ice pain threshold, produced effects of a lesser magnitude. The frequency of pulse delivery was the governing factor as no significant differences in stimulus intensity were observed across the treatment groups. Measurement of ice pain tolerance was found to be unreliable under the present conditions. No significant relationships were observed between personality variables as measured by Eysenck Personality Questionnaires and the degree of TENS response.