Pilot Study on Dose-Dependent Effects of Transcranial Photobiomodulation on Brain Electrical Oscillations: A Potential Therapeutic Target in Alzheimer’s Disease

Article type: Research Article

Authors: Spera, Vincenza^{a; b; 1} | Sitnikova, Tatiana^{a; c; d; 1} | Ward, Meredith J.ⁱ | Farzam, Parya^{c; e} | Hughes, Jeremy^{c; e} | Gazecki, Samuel^a | Bui, Eric^{a; d} | Maiello, Marco^{a; b} | De Taboada, Luis^f | Hamblin, Michael R.^{g; h} | Franceschini, Maria Angela^{c; e} | Cassano, Paolo^{a; d; *}

Affiliations: [a] Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA | [b] Department of Clinical Experimental Medicine, Psychiatric Unit, University of Pisa, Pisa, Italy | [c] HMS/MGH Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA | [d] Department of Psychiatry, Harvard Medical School, Boston, MA, USA | [e] Department of Radiology, Massachusetts General Hospital, Boston, MA, USA | [f] LiteCure LLC, New Castle, DE, USA | [g] Laser Research Centre, Faculty of Health Science, University of Johannesburg, Doornfontein, South Africa | [h] Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran | [i] School for Social Work, Smith College, Northampton, MA, USA

Correspondence: [*] Correspondence to: Paolo Cassano, MD, PhD, Department of Psychiatry, Harvard Medical School, 149 13th Street (2612), Boston, MA 02129, USA. Tel.: +1 617 643 9622; Fax: +1 617 726 5780; E-mail: [email protected].

Note: [1] These authors contributed equally to this work.

Abstract: Background:Transcranial photobiomodulation (tPBM) has recently emerged as a potential cognitive enhancement technique and clinical treatment for various neuropsychiatric and neurodegenerative disorders by delivering invisible near-infrared light to the scalp and increasing energy metabolism in the brain. Objective:We assessed whether transcranial photobiomodulation with near-infrared light modulates cerebral electrical activity through electroencephalogram (EEG) and cerebral blood flow (CBF). Methods:We conducted a single-blind, sham-controlled pilot study to test the effect of continuous (c-tPBM), pulse (p-tPBM), and sham (s-tPBM) transcranial photobiomodulation on EEG oscillations and CBF using diffuse correlation spectroscopy (DCS) in a sample of ten healthy subjects [6F/4 M; mean age 28.6±12.9 years]. c-tPBM near-infrared radiation (NIR) (830 nm; 54.8 mW/cm2; 65.8 J/cm2; 2.3 kJ) and p-tPBM (830 nm; 10 Hz; 54.8 mW/cm2; 33%; 21.7 J/cm2; 0.8 kJ) were delivered concurrently to the frontal areas by four LED clusters. EEG and DCS recordings were performed weekly before, during, and after each tPBM session. Results:c-tPBM significantly boosted gamma (t = 3.02, df = 7, p < 0.02) and beta (t = 2.91, df = 7, p < 0.03) EEG spectral powers in eyes-open recordings and gamma power (t = 3.61, df = 6, p < 0.015) in eyes-closed recordings, with a widespread increase over frontal-central scalp regions. There was no significant effect of tPBM on CBF compared to sham. Conclusion:Our data suggest a dose-dependent effect of tPBM with NIR on cerebral gamma and beta neuronal activity. Altogether, our findings support the neuromodulatory effect of transcranial NIR.

Keywords: Cerebral blood flow, EEG oscillations, light-emitting diode, photobiomodulation, transcranial light therapy, transcranial near-infrared light

DOI: 10.3233/JAD-210058

Journal: Journal of Alzheimer's Disease, vol. 83, no. 4, pp. 1481-1498, 2021