Audio-visual entrainment: a review of the evidence (Rahmani 2025)

Findings are heterogeneous and include null or limited effects. The review concludes that it is premature to say the technique is effective and that rigorous, standardized, adequately controlled studies are needed.

A plain-language summary from binaural's reading notes, edited by Jude Mc. Last updated 10 November 2026. Not medical advice.

The question: What does research show about audio-visual entrainment (synchronized light and sound flicker) for conditions such as depression, insomnia and pain?

What it found

• Findings are heterogeneous and include null or limited effects.
• The review concludes that statements of efficacy are premature and that the field needs rigorous, standardized, adequately controlled studies.
• Much of the supportive literature cited in device marketing traces to studies co-authored by a device manufacturer's founder, not to independent labs.
• An older appraisal (Huang & Charyton 2008), re-appraised by the NHS CRD/DARE database, was judged "not reliable" given methodological weakness.
• The review itself reports no funding and no declared conflicts.

Limits

• No adequately powered, independently replicated randomized trial of audio-visual entrainment exists.
• This is a narrative review, not a systematic one.

Where this sits

More in the library on light, flicker and 40 hz. For the wider picture, read 40 Hz, gamma and the brain.

This is our plain-language reading of the paper. It is not medical advice, and one study rarely settles a question.