Effect of transcranial direct current stimulation on cortico-muscular coherence and standing postural steadiness

Abstract

Non-invasive brain stimulation is a promising tool for inducing cortico-spinal excitability and facilitating motor function. The objective of this study was to investigate the effect of transcranial DC stimulation (tDCS) on cortico-spinal excitability of leg area, cortico-muscular coherence of tibialis anterior muscle, and standing postural steadiness there from. In single-blind, sham-controlled, crossover study, five healthy subjects were evaluated under two conditions - with 10min anodal tDCS and with 10min sham tDCS. Anodal tDCS induced statistically significant (P=0.001, N=20) cortico-spinal excitability, 45min and 60min after the end of tDCS as revealed by single pulse transcranial magnetic stimulation (TMS) of resting tibialis anterior muscle. Furthermore, anodal tDCS induced statistically significant (P=0.001, N=20) cortico-muscular coherence in tibialis anterior muscle during quiet standing with eyes closed, 45min and 60min after the end of tDCS. The % change in the stabilogram metrics after anodal tDCS during quiet standing with eyes closed showed that anodal tDCS strongly (P=0.0000) affected the change in centroid of CoP data-points in medio-lateral direction (%CoP(ML)) at 45min and 60min after tDCS session. Anodal tDCS had moderate effect (P=0.0113) on the change (decrease) in the path length of CoP trajectory (%CoP(PL)) at 60min after tDCS. Also, anodal tDCS had a strong (P=0.0000) effect on the change (decrease) in sway area (%CoP(EA)) at 45min and 60min after tDCS session. Language: en