Transcranial photobiomodulation for neurodevelopmental disorders: a narrative review

Area of Science:

• Neuroscience
• Biomedical Engineering

Background:

• Neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Down syndrome (DS), present significant challenges in social, communicative, and behavioral functioning.
• Transcranial photobiomodulation (t-PBM), a non-invasive neurostimulation technique using near-infrared light, is emerging as a potential therapeutic strategy for neuropsychiatric conditions, particularly NDDs.

Purpose of the Study:

• To conduct a narrative review examining the existing preclinical and clinical evidence for the efficacy of photobiomodulation (PBM) in the treatment of neurodevelopmental disorders (NDDs).

Main Methods:

• A systematic literature search was performed across six databases using relevant keywords and MeSH terms for "photobiomodulation" (PBM) and "neurodevelopmental disorders" (NDDs).
• Included studies involved PBM application in diagnosed NDD cases or relevant animal models, focusing on clinical or cognitive outcomes.
• Excluded were protocols, reviews, non-English studies, and those lacking outcome evaluation.

Main Results:

• Nine studies (1 preclinical, 8 clinical) were analyzed, focusing on ASD (5 studies), ADHD (2 studies), and DS (1 study).
• t-PBM, utilizing wavelengths from 635-905 nm and targeting the frontal cortex, demonstrated improvements in disruptive behavior, social communication, cognitive rigidity, sleep, and attention in ASD.
• Positive effects were also observed in attention for ADHD and motor skills/verbal fluency for DS, with minimal reported adverse effects. Proposed mechanisms include enhanced mitochondrial function, reduced oxidative stress, and decreased neuroinflammation.

Conclusions:

• t-PBM presents a promising non-invasive intervention for NDDs, showing potential therapeutic benefits across ASD, ADHD, and DS.
• Further research, including large-scale randomized sham-controlled trials with detailed biomarker analysis, is crucial to optimize t-PBM parameters and elucidate its underlying therapeutic mechanisms.