Gao F. et al. - Photobiomodulation and ABC Symptoms of Alzheimer's Disease: A Bayesian Network Meta-Analysis

This Bayesian network meta-analysis compares five pharmacological and nonpharmacological interventions for Alzheimer’s disease based on 91 randomized trials and 12,242 participants. Photobiomodulation and repetitive transcranial magnetic stimulation show the greatest impact on cognitive function, while independence and quality of life respond more to other approaches.

What this study measured

Direct comparisons between drug and non-drug treatments for Alzheimer’s disease are rare. The authors therefore conducted a Bayesian network meta-analysis, a method that allows for the indirect comparison of interventions that have never been tested against one another in the same trial.

Five interventions were compared: pharmacological treatment, photobiomodulation, cognitive therapy, physical exercise, and repetitive transcranial magnetic stimulation. The evaluation focused on what the authors refer to as the ABC symptoms: activities of daily living, behavioral and psychological symptoms, and cognitive function, in addition to quality of life. Of the 6,450 references reviewed, 91 randomized trials involving a total of 12,242 participants met the inclusion criteria.

Key Findings

Each contribution focuses on a different area, which is the central message of this work.

• 91 randomized clinical trials were included, involving 12,242 participants, selected from 6,450 references reviewed.
• Cognitive function: photobiomodulation and repetitive transcranial magnetic stimulation show significant benefits.
• Activities of daily living: Pharmacological treatment and cognitive therapy appear to be the most effective.
• Quality of life: Cognitive therapy and physical exercise stand out as the most beneficial options.
• A total of five interventions were compared, with distinct efficacy profiles depending on the area under consideration.

The authors conclude that combining pharmacological and non-pharmacological approaches could optimize care, with each intervention addressing a specific need.

How photobiomodulation works for this indication

Transcranial photobiomodulation involves applying red or near-infrared light to the skull. The mechanisms discussed in the literature are based on the absorption of these wavelengths by mitochondrial cytochrome c oxidase, which is associated with changes in neuronal energy metabolism, cerebral blood flow, and inflammatory processes.

This meta-analysis does not test any of these mechanisms. It compares only aggregated clinical outcomes. The positive effect of photobiomodulation on cognitive function is therefore a statistical finding, not a mechanistic demonstration.

Limits You Should Know

A network meta-analysis relies heavily on indirect comparisons. Its validity depends on the transitivity assumption—that is, the comparability of populations, disease stages, and protocols across the trials in the network. Pooling 91 trials involving five very different interventions exposes the analysis to significant heterogeneity.

The summary does not provide quantified effect sizes, credibility intervals, or an assessment of the certainty of the evidence for each comparison. Nor does it specify the photobiomodulation parameters used in the relevant trials or the number of trials specifically dedicated to this intervention. These factors limit the immediate practical applicability of the findings. Finally, it should be noted that photobiomodulation showed no benefit in terms of independence or quality of life.

What This Means in Practice

This study supports the hypothesis that photobiomodulation may be beneficial for the cognitive aspects of Alzheimer’s disease, in line with other recent reviews. Above all, it offers a useful caveat: this benefit does not extend to all areas, and other interventions remain preferable for promoting independence or quality of life.

Photobiomodulation is not a substitute for neurological monitoring, prescribed treatments, or validated non-pharmacological interventions. Any decision to incorporate it into a care plan must be discussed with the medical team treating the patient.

Frequently Asked Questions

Does photobiomodulation improve memory in Alzheimer's disease?

In this network meta-analysis, it is listed among the interventions associated with a significant benefit on cognitive function. The abstract does not specify the magnitude of this effect or its duration.

Can it replace medication?

No. On the contrary, the authors suggest combining pharmacological and non-pharmacological approaches. No prescribed treatment should be discontinued without medical advice.

What is a Bayesian network meta-analysis?

It is a statistical method that compares several interventions with one another—even when they have never been directly tested against each other—by drawing on the available network of comparisons.

Reference

Gao F, Luo G, Liu B, Qiu X, Bai J, Wang R. Comparative effectiveness of multiple interventions for Alzheimer’s disease on ABC syndromes and quality of life: A Bayesian network meta-analysis. iScience, 2026;29(9):117250. PMID 42668611. Read on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.