Low-Level Laser Therapy in Stroke and Central Nervous System

Field: Medicine (Health Sciences)

Ying-Ying Huang
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston MA;
Department of Dermatology, Harvard Medical School, Boston MA Aesthetic Plastic Laser Center,
Guangxi Medical University, Nanning, Guangxi, P. R. ChinaMichael R Hamblin
Wellman Center for Photomedicine, Massachusetts General Hospital, Boston MA Department of
Dermatology, Harvard Medical School, Boston MA Harvard-MIT Division of Health Sciences and
Technology, Cambridge MALuis De Taboada
PhotoThera Inc, Carlsbad, CA27.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
27.2 Photobiology of Low-Level Laser Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
27.3 LLLT Effects on Nerves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719
27.4 Human Skull Transmission Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720
27.5 The Problem of Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 721
27.6 TLT for Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 724
27.7 LLLT for CNS Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727
27.8 LLLT for Neurodegenerative Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 730
27.9 LLLT for Psychiatric Disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 731
27.10Conclusions and Future Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 731References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 733Low-level laser/light therapy (LLLT) for neurological disorders in the central nervous system (CNS)
is currently an experimental concept. The broad goals for clinical utilization are the prevention
and/or repair of damage, relief of symptoms, slowing of disease progression, and correction of genetic abnormalities. Experimental studies have tested and continue to test these goals by investigating LLLT in animal models of diseases and injuries that affect the brain and spinal cord. Successful
clinical trials have been carried out of transcranial laser therapy for stroke. Discoveries concerning
the molecular basis of various neurological diseases, combined with advances that have been made
in understanding the molecular and cellular mechanisms in LLLT, both in vitro and in vivo, have
allowed rational light-based therapeutic approaches for a wide variety of CNS disorders to be investigated. Limitations in knowledge are still apparent, such as the optimal wavelength, light source,
doses, pulsed or CW, polarization state, treatment timing, and repetition frequency. Collaborative
efforts between clinicians and basic researchers will likely increase the usage and understanding of
effective laser-based therapies in the CNS.