Sound and Light at 40 Hertz
By Kathi Mestayer
Credit: @pawel_czerwinski/Unsplash
While reading a really fun book (“Reverberation” by Keith Blanchard), I ran across a fascinating story about recent research on the effect that sound and light waves might have on the progress of Alzheimer’s disease. The results of the early-stage study, conducted at MIT’s Picower Institute for Learning and Memory, were published in the academic journal, PLoS ONE, in 2022.
On the MIT News website, David Orenstein, the director of communications for the Picower Institute, summarizes the early, relatively small study, which involved a group of 15 volunteers with early-stage Alzheimer’s.
Of that group, eight people exposed themselves for an hour each day, for three months, to simultaneous light and sound stimulation at the frequency of 40 Hertz (Hz)—also known as “gamma” waves. The control group of seven people used the same procedure, but were exposed to “non-40 Hz ‘sham’ stimulation.”
Why 40 Hertz?
According to the MIT Media Lab website, research has shown that frequencies of around 40 Hz (for sound, about the lowest E key on a piano) play fundamental roles in our brains. Specifically, healthy brains hum with this frequency, which in turn activates many functions central to mental sharpness. Stimulating gamma activity levels in the brain may increase the activity of microglial cells, which are the primary immune cells in the brain, and can destroy pathogens and remove damaged cells.
Study Results
After three months, the study results showed slight differences between the test group and the control group. According to the Orenstein article on the MIT website, “Neither the treatment nor control groups showed any differences after just three months on most cognitive tests, but the treatment group did perform significantly better on a face-name association test, a memory task with a strong visual component. Treated patients also exhibited better connectivity across brain regions involved in the brain’s default mode and medial visual networks, which are related to cognition and visual processing respectively.”
More research is, in fact, in progress. the MIT Tsai Lab website notes that there are now 15 new clinical studies of gamma stimulation underway. Among these is a phase III clinical trial by the company Cognito Therapeutics, which has licensed MIT’s technology. That study is enrolling participants online.
Hearing Health magazine staff writer Kathi Mestayer is the vice president of the Greater RIchmond Virginia Chapter of the Hearing Loss Association of America.