Maryam Ebrahimian - Department of Physiotherapy, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
Mohsen Razeghi - Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Alireza Motealleh - Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran

Transcutaneous electrical nerve stimulation (TENS) is an inexpensive, non-invasive and safe technique to reduce acute and chronic pain. Despite all of these benefits, limited studies have been conducted on its therapeutic effects on brain electrical activity. According to our knowledge, no study has been done on the therapeutic effects of TENS on beta band activity. Investigation of the effect of high-frequency TENS on the electroencephalographic (EEG) beta band activity following induced pain in healthy subjects. The modified version of the submaximal effort tourniquet technique was used to induce tonic pain in 15 right-handed volunteers. After that, high frequency TENS (150ms in duration, frequency of 100 Hz) was applied for 20 minutes. Using Visual Analog Scale (VAS) pain intensity was assessed in two conditions (after-pain, after-TENS). Beta band activity was recorded by the 19-channel EEG in three conditions (baseline, after-pain and after- TENS). The repeated measure ANOVA and paired-sample T- tests were used for data analysis. The findings of this study showed that after pain induction the mean power of beta band was increased (compared to baseline) and without change after TENS (mean±SD: .088±.045 to .197±.064 to .147±.066 mV2). The analysis of VAS values demonstrated that the intensity of induced pain (mean±SD: 51.53±9.86) decreased after the application of TENS (mean±SD: 18.66±10.28). All these differences were statistically significant (p<.001). The results of this study revealed that the high frequency TENS can’t reduce the enhanced beta band activity after the induction of tonic pain in healthy volunteers. This finding might help as a functional brain biomarker which could be useful for pain treatment, specifically for EEG-based neurofeedback approaches.

Transcutaneous electric nerve stimulation (TENS), Beta rhythm, Pain measurement, Tourniquet pain test, Electroencephalography (EEG)