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

Abstract

Background: Transcranial near-infrared photobiomodulation (NIR-PBM) is a new noninvasive procedure which transcranially applies near-infrared wavelength with laser or light emitting diode source on the scalp. Improvement of the neurological or psychological symptoms has been reported following light irradiation. However, to our knowledge, there is no study to investigate transcranial NIR-PBM effects on motor performance. 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, 56 right handed healthy participants ranging from 18 to 30 years old were randomly assigned to:1) Real transcranial NIR-PBMC3 group (n=14), 2) Sham transcranial NIR-PBMC3 group (n=14), 3) Real transcranial NIR-PBMC4 group (n=14), and 4) Sham transcranial NIR-PBMC4 group (n=14). We applied 808nm laser with irradiation energy density 60J/cm2 and power density 200mw/cm2 on the C3 or C4 points of the scalp. Number of finger taps as an indicator of motor performance was assessed by the finger tapping test before and after irradiation of transcranial NIR-PBM on the corresponding points of the scalp for 5 min. Results: The results showed that the number of finger taps in both right and left hands following transcranial NIR-PBM in real transcranial NIR-PBMC3 group was significantly increased (p<0.05). Conclusion: We concluded that using transcranial NIR-PBM with laser source on C3 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.