Researchers are testing transcranial photobiomodulation — light applied to the head — for brain health. Near-infrared light is often applied to the forehead, where penetration is better (no hair, longer wavelength), and inexpensive LED arrays have made light-emitting helmets possible.[1] Reviews propose that light boosts mitochondrial energy production in neurons and triggers anti-inflammatory and protective effects.[2]
Healthy volunteers
In a placebo-controlled study, 40 healthy volunteers (20 treated, 20 placebo) received infrared laser stimulation to the forehead. The treated group showed significantly faster reaction times on a sustained-attention task, better performance on a memory task, and more sustained positive mood over the following two weeks.[3]
Dementia
A 2022 systematic review and meta-analysis pooled 13 studies with 608 participants with dementia. Phototherapy was associated with improvements in global cognition, particularly attention, executive function and working memory, and near-infrared LEDs and lasers outperformed ordinary visible light. Short-term improvement was supported, but evidence for long-term benefit was lacking.[4]
Where this leaves us
Brain PBM is one of the most exciting frontiers in the field, but it is still emerging: studies are small, protocols vary, and dedicated head-worn devices differ from general-purpose panels. Anyone considering light therapy for a neurological condition should do so with their medical team.
References
- Hamblin MR (2016). Shining light on the head: Photobiomodulation for brain disorders. BBA Clin. PubMed 27752476 · Free full text
- Salehpour F, Mahmoudi J, Kamari F et al. (2018). Brain Photobiomodulation Therapy: a Narrative Review. Mol Neurobiol. PubMed 29327206 · Free full text
- Barrett DW, Gonzalez-Lima F (2013). Transcranial infrared laser stimulation produces beneficial cognitive and emotional effects in humans. Neuroscience. PubMed 23200785
- Zhu G, Tong Q, Ye X et al. (2022). Phototherapy for Cognitive Function in Patients With Dementia: A Systematic Review and Meta-Analysis. Front Aging Neurosci. PubMed 35847661 · Free full text