Transcranial photobiomodulation increases cognition and serum BDNF levels in adults over 50 years: A randomized, double-blind, placebo-controlled trial

Background

There is a significant lack of therapeutic options for mild cognitive impairment (MCI), which is rapidly becoming a global epidemic due to aging. Transcranial photobiomodulation (t-PBM) involves delivering near-infrared light (NIR) to the scalp, targeting cortical areas of the brain. NIR t-PBM has recently emerged as a potential therapy for various neurodegenerative conditions, including memory issues.

Aims

This study aimed to evaluate cognition scores (primary outcome), depression, anxiety, resilience scores, neuroplasticity, and neurodegeneration biomarkers (secondary outcomes) in individuals with MCI undergoing t-PBM therapy or receiving a placebo.

Materials and Methods

A total of 93 older adult individuals with MCI were randomly assigned to either a t-PBM (n = 47) or Placebo (n = 46) group. Clinical assessments were conducted at baseline, 60 days post-treatment, and a 150-day follow-up. We also measured serum levels of brain-derived neurotrophic factor (BDNF), a neuroplasticity biomarker, as well as neuron-specific enolase (NSE) and calcium-binding protein B (S100B), which are neurodegeneration biomarkers. Intervention effects were analyzed using repeated measures (RM) two-way ANOVA followed by Tukey post hoc test. Fischer's exact test and Generalized Estimating Equations (GEE) were also applied.

Results

Of the 93 older adults individuals invited to participate, 76 (t-PBM: 40, placebo: 36) completed the study. The t-PBM significantly improved cognition as measured by the Montreal Cognitive Assessment (MoCA) compared to placebo (p = 0.0301). The delta values for MoCA scores were 3.20 in the t-PBM group and 1.97 in the placebo group. This effect persisted until the three-month follow-up, accompanied by increased BDNF levels in the t-PBM group but not in the placebo group (p = 0.0046). The delta values for BDNF were 821.94 in the t-PBM group and 359.41 in the placebo group. t-PBM did not alter depression, anxiety, resilience scores, nor the levels of NSE and S100B in individuals with MCI.

Conclusion

The t-PBM increases cognitive function and BDNF levels in adults with MCI. Its application as an adjunctive treatment may play a crucial role in preventing neurodegenerative diseases.