Brain Photobiomodulation Therapy: a Narrative Review.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic and preliminary evidence without systematic search or meta-analysis
PubMed 29327206 · doi:10.1007/s12035-017-0852-4
What was done
This narrative review summarizes preclinical and clinical literature on brain photobiomodulation (PBM) therapy using red to near-infrared (NIR) light across neurological and psychological conditions, detailing putative molecular mechanisms and delivery modalities.
What was found
The abstract reports no quantitative clinical data, sample sizes, or effect estimates. It outlines proposed mechanisms including stimulation of mitochondrial cytochrome c oxidase (complex IV), increased ATP synthesis, calcium release via ion channels, and downstream activation of transcription factors leading to anti-inflammatory, antioxidant, anti-apoptotic, neurogenic, and synaptogenic effects. Disorders mentioned include dementia, Parkinson's disease, stroke, brain trauma, and depression. A key physical limitation noted is the exponential attenuation of light penetration through tissue during transcranial delivery.
Why it matters
It consolidates the mechanistic rationale for light-based brain stimulation while highlighting tissue penetration as the primary barrier to effective transcranial dosing.
Limits
The paper is a narrative review without systematic search criteria, quality assessment, or pooled quantitative results. No human trial data, effect sizes, or participant numbers are reported in the abstract. Clinical efficacy remains constrained by physical barriers to transcranial light delivery.
Cited by
- supports Photons of long-wavelength light impact electrons in mitochondria, leading to increased ATP and cellular energy production.