Effects of Transcranial Photobiomodulation on Motor Functions in Healthy Individuals: A Randomized Controlled Trial.

ObjectiveThis study investigated the effects of transcranial photobiomodulation (tPBM) targeting the supplementary motor area (SMA) on motor performance and neural activity in healthy individuals.MethodsIn a randomized, double-blind, sham-controlled trial, 60 right-handed participants received active tPBM (850 nm, 60 mW/cm2, 36 J/cm2) or sham stimulation over the SMA for four consecutive days. Motor performance was assessed using a sequential finger-tapping task for both hands. Neural activity was evaluated using quantitative electroencephalography (qEEG) at rest.ResultsActive tPBM significantly improved non-dominant hand motor performance compared to sham, with reductions in reaction time and total movement time, and increased accuracy (all p < 0.001 after Bonferroni correction). qEEG showed significant increases in alpha and beta power at C3 and C4 electrodes in the active group (all p < 0.001 after correction). No significant changes were observed in the sham group.ConclusionThese findings suggest that short-term tPBM targeting the SMA can enhance motor performance, particularly of the non-dominant hand, and increase sensorimotor alpha and beta power in healthy young adults. Further research is needed to clarify the underlying mechanisms and potential clinical applications.