Pulse frequency is one of the key determinants of analgesic outcomes by transcutaneous electrical nerve stimulation (TENS). However, ideal setting are still not certain. The purpose of this study was to compare the effects of different frequencies of TENS, on pressure pain threshold and tolerance. Currents with pulse duration of 110 μs, and pulse frequencies of 60 pps or 150 pps were applied on the volar aspects of the dominant forearms of 20 healthy volunteers, on two consecutive days, in a randomized order. Threshold and tolerance were measured prior to, after the 15th and 30th minutes of the applications, and 30 post application. Pressure pain threshold and tolerance values were higher at the 150 pps frequency, at all measurement times (p< 0.05). However, no frequencyXtime interaction and time-dependent changes were found for the outcome measures (p> 0.05).
The findings of this study established that, at 150 pps conventional TENS, threshold and tolerance values were consistently higher. These results are presented to inform future research regarding optimal conventional TENS parameters and to provide assistance for clinical applications.