Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological method already established in the modulation of acute and chronic pain. The purpose of this study was to assess the effect of conventional TENS and acupuncture-like TENS on cold-induced pain. Thirty healthy subjects aged 18 to 40 years old were randomized into in three groups: placebo, conventional TENS, and acupuncture-like TENS. A cold-induced pain protocol was used, in six cycles (two pre-treatment, two during, and two after treatment); TENS was applied for 20 minutes through 2 channels, the conventional modality at sensory level at 80 Hz, and the acupuncture modality at motor level at 4 Hz. Variables analysed were pain threshold, tolerance to pain, and pain intensity. No statistically significant differences were found in any variable between post and pre-treatment measures in all groups. Hence neither conventional or acupuncture-like TENS had any effect on cold-induced pain. Further studies are suggested, with different experimental pain models, and with longer time of TENS application.
Pain; Pain threshold; Transcutaneous electric nerve stimulation
