The modulatory effect of transcutaneous electrical nerve stimulation (TENS) on tonic heat pain in the human brain: topographic mapping of absolute EEG power spectra

Abstract

Objective To investigate the effect of transcutaneous electrical nerve stimulation (TENS) on baseline eyes-closed brain activation and on pain-related EEG activity when TENS is applied contralatarally to the hand of pain. Method 128-channel electroencephalography (EEG) was recorded in four conditions including baseline,heat pain test,TENS stimulation and contralateral TENS modulation in 15 right-handed healthy young males. The Short Form McGill Pain Questionnaire was employed to assess pain sensation. Fast Fourier Transformation analysis (FFT) was performed to calculate absolute EEG power spectra based on 7 bands spectrum. Results ① The fronto-central beta-1 activity was significantly enhanced by TENS compared to eyes-closed [eyes-closed:(290±201)μV2,TENS:(385±224)μV2,t=3.323,P<0.01].②TENS markedly relived pain sensation assessed by SF-MPQ and significantly increased the posterior-anterior alpha-1 power [pain:(332±221)μV2,TENS modulation:(378±243)μV2,t=3.683,P<0.01] and fronto-central and posterior beta-1 activities [pain:(348±213)μV2,TENS modulation:(397±240)μV2,t=2.362,P<0.05]. Conclusion TENS,used as a peripheral nerve stimulation,mainly activates sensorimotor cortex.The increased Alpha-1 activity implies that TENS is likely able to relieve pain affective. Key words: TENS; Tonic heat Pain; Absolute EEG power spectra