The effects of transcranial direct current stimulation combined with aerobic exercise on pain thresholds and electroencephalography in healthy adults.

Abstract

OBJECTIVES\nWe examined whether transcranial direct current stimulation (tDCS) combined with aerobic exercise (AE) modulated the pressure pain threshold (PPT) and peak alpha frequency (PAF) measured via resting electroencephalography.\n\n\nDESIGN\nSingle-blind experimental study with a cross-over design.\n\n\nSETTING\nNeuro Rehabilitation Research Center, Kio University.\n\n\nSUBJECTS\nTen healthy controls participated in this study.\n\n\nMETHODS\nThree types of sessions, (i) tDCS, (ii) Sham tDCS/AE, and (iii) tDCS/AE, were tested in this investigation. Anodal stimulation (2 mA, 20 min) was applied over the left primary motor cortex. Each session was 20 min long. We used the PPT and short-form Profile of Mood States-Brief, as well as PAF measured via restingelectroencephalography, to investigate the effects of tDCS and AE. Heart rate and scores on the Borg scale were used to confirm exercise intensity. PAF was calculated in four regions of interest: frontal, central, parietal, and occipital areas.\n\n\nRESULTS\nThe change ratio of PPT increased during each session. The maximum change ratio of PPT were tDCS: 40.7%, Sham tDCS/AE: 51.5%, and tDCS/AE: 83.4%. change ratio of PPT was earlier and higher in the tDCS/AE trials compared with the other sessions. Negative mood was improved after session completion. Significant differences in PAF were found in the occipital area in the Sham tDCS/AE and tDCS/AE sessions.\n\n\nCONCLUSIONS\nThe combined tDCS and AE intervention induced significant changes in PPT in a single session, with a PAF that was earlier and higher than those produced during the Sham tDCS/AE and tDCS sessions.