A randomized pilot trial of non-flickering 40 Hz light stimulation: EEG activity and cognitive outcomes in cognitively normal older adults

The non-flickering 40 Hz approach was well tolerated, but it did not change the study's main EEG measures more than the active comparison. Selected memory findings were encouraging but exploratory and need confirmation in a larger trial.

Cheng CH, Lu H.
Journal of Alzheimer’s Disease · Publication date: 2026-10-08
Added to site: 2026-10-10
DOI: 10.1177/13872877261494219

First published online October 8, 2026. Added to Neurofeedback.com October 10, 2026.

Modalities

Light stimulation, EEG

Clinical focus

Gamma-frequency sensory stimulation, Cognitive aging

Population

Cognitively normal older adults

Sample

33 randomized participants; 29 completed the intervention and were included in per-protocol analyses

Intervention / method

Twenty-eight sessions over four weeks of non-flickering 40 Hz light stimulation

Comparator

Non-flickering 70 Hz active-control light stimulation

Clinician summary

No significant between-group differences were found for prespecified gamma-band power or functional-connectivity outcomes after one or 28 sessions. Unadjusted secondary analyses suggested improvement on selected episodic-memory measures, and an exploratory association linked visuospatial-memory change with occipital-temporal connectivity change.

How to interpret the findings

This was a small pilot with four noncompleters and per-protocol analysis. The prespecified EEG outcomes were null, cognitive signals came from unadjusted secondary analyses, the connectivity association was exploratory, and the healthy sample does not establish benefit for cognitive impairment or Alzheimer disease. The checked abstract does not provide detailed adverse-event counts or durability after treatment.

Equipment and disclosures

Non-flickering light-stimulation equipment was used, but the checked abstract does not identify a device model; no product attribution is made.

Crossref records support from Aleddra, Inc., Taiwan's National Science and Technology Council and the Healthy Aging Research Center. Full conflict-of-interest declarations were not available in the checked abstract, so commercial relationships beyond the recorded funding could not be evaluated.

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