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REVIEW ARTICLE
Transcranial low level laser (light) therapy
for traumatic brain injury
Ying-Ying Huang1;2;3, Asheesh Gupta1;2;4, Daniela Vecchio 1;2, Vida J. Bil de Arce1,
Shih-Fong Huang1;2;5, Weijun Xuan1;2;6, and Michael R. Hamblin*;1;2;7
1Wellman Center for Photomedicine, Massachusetts General Hospital, BAR414, 40 Blossom Street, Boston, MA 02114, USA
2Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA
3Aesthetic and Plastic Center of Guangxi Medical University, Nanning, China
4Defence Institute of Physiology and Allied Sciences, Timarpur, Delhi-110 054, India
5Taipei Veterans General Hospital, Beitou District, Taipei City, Taiwan 112
6Department of Otolaryngology, Traditional Chinese Medical University of Guangxi, Nanning, China
7Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
Received 26 April 2012, revised 12 June 2012, accepted 13 June 2012
Published online 17 July 2012
Key words: Low level laser therapy, photobiomodulation, NIR laser, traumatic brain injury, stroke, mouse models,
neurogenesis, clinical trials
1. Introduction
Traumatic brain injury (TBI) includes skull fractures,
intracranial hemorrhages, elevated intracranial pres-
sure, and cerebral contusion. Unlike stroke, which is
often associated with senior citizens, TBI affects a
predominantly young population. Severe and mod-
erate TBI, whether accidental or inflicted, is a major
health and socio-economic problem throughout the
world. In the United States alone, approximately
2 million injuries occur each year resulting in
56,000 deaths and 18,000 survivors suffering from
#2012 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Journal of
BIOPHOTONICS
Early View publication on
www.wileyonlinelibrary.com
(issue and page numbers not yet assigned;
citable using Digital Object Identifier – DOI)
We review the use of transcranial low-level laser (light)
therapy (LLLT) as a possible treatment for traumatic-
brain injury (TBI). The basic mechanisms of LLLT at the
cellular and molecular level and its effects on the brain
are outlined. Many interacting processes may contribute
to the beneficial effects in TBI including neuroprotec-
tion, reduction of inflammation and stimulation of neuro-
genesis. Animal studies and clinical trials of transcranial-
LLLT for ischemic stroke are summarized. Several la-
boratories have shown that LLLT is effective in increas-
ing neurological performance and memory and learning
in mouse models of TBI. There have been case report
papers that show beneficial effects of transcranial-LLLT
in a total of three patients with chronic TBI. Our labora-
tory has conducted three studies on LLLT and TBI in
mice. One looked at pulsed-vs-continuous wave laser-ir-
radiation and found 10 Hz to be superior. The second
looked at four different laser-wavelengths (660, 730, 810,
and 980 nm); only 660 and 810 nm were effective. The
last looked at different treatment repetition regimens (1,
3 and 14-daily laser-treatments).
Schematic of transcranial LLLT employed for stroke.
*Corresponding author: e-mail: hamblin@helix.mgh.harvard.edu, Phone: 617-726-6182, Fax: 617-726-8566
J. Biophotonics 1–11 (2012) / DOI 10.1002/jbio.201200077
