Short-term Effects of Transcranial Near-Infrared Photobiomodulation on Motor Performance in Healthy Human Subjects: An Experimental Single-Blind Randomized Clinical Trial

Abstract Introduction: Transcranial near-infrared photobiomodulation (NIR-PBM) is a new noninvasive procedure which transcranially applies a near-infrared wavelength to the scalp with a laser or a light-emitting diode (LED) source. Improvement in the neurological or psychological symptoms has been reported following light irradiation. However, to our knowledge, there is no study to investigate the effects of transcranial NIR-PBM on motor performance directly. Therefore, the objective of this study was to investigate the short-term effects of transcranial NIR-PBM on motor performance in healthy human subjects.Methods: In this experimental single-blind randomized clinical trial study, ۵۶ right-handed healthy participants, whose ages ranged from ۱۸ to ۳۰, were randomly assigned to (۱) Real transcranial NIR-PBMC۳ group (n=۱۴), (۲) Sham transcranial NIR-PBMC۳ group (n=۱۴), (۳) Real transcranial NIR-PBMC۴ group (n=۱۴), and (۴) Sham transcranial NIR-PBMC۴ group (n=۱۴). We applied the ۸۰۸ nm laser with irradiation energy density of ۶۰ J/cm۲ and power density of ۲۰۰ mw/cm۲ to the C۳ or C۴ points of the scalp. The number of finger taps as an indicator of motor performance was assessed by the finger-tapping test (FTT) before and after irradiation of transcranial NIR-PBM on the corresponding points of the scalp for ۵ minutes.Results: The results showed that the number of finger taps in both right and left hands following the use of transcranial NIR-PBM in the real transcranial NIR-PBMC۳ group significantly increased (P < ۰.۰۵).Conclusion: We concluded that using transcranial NIR-PBM with a laser source on C۳ point of the motor cortex in right-handed healthy people can increase the number of finger taps in both hands as an indicator of motor performance improvement. Keywords: Transcranial Cytochrome-c oxidase Laser Motor cortex.