What is it about?

We examined measurements of brainwave activity recording during routine examination of 1464 patients of varying age. Patients looked at flickering light at 40 Hz. This induces a rhythm in their brainwave activity at the same, i.e. 40 Hz, frequency. We found that there were individual differences in the susceptibility to the response but that advancing age did not appear to fundamentally alter the response.

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Why is it important?

Flickering light may be a way to influence the brain's metabolism and immune activity. This has previously been explored in mice models of Alzheimer's disease as a potential treatment. Patients with Alzheimer's Disease are often old and it is not known to what extent age might affect the light stimulation effect. Basic physiology experiments are often carried out on young people, but since most patients with Alzheimer's Disease are old, it is important to know if the response to flickering changes substantially with age or not. We found that is does not. This is relevant baseline knowledge for assumptions underlying future research into the potential therapeutics effects of light stimulation in Alzheimer's Disease.


A study of masked light as a therapeutic intervention for Alzheimer's disease is planned. This study helps rule out differences caused by age when testing the basic physiological response in people of different age.

Ivan Zibrandtsen
Zealand University Hospital

Read the Original

This page is a summary of: Gamma Entrainment in a Large Retrospective Cohort: Implications for Photic Stimulation Therapy for Alzheimer’s Disease, Journal of Alzheimer s Disease, June 2020, IOS Press, DOI: 10.3233/jad-200083.
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