Sound and Light as Potential Alzheimer’s Treatment

A new study describes the first human trials of an experimental cure for Alzheimer’s that uses sound and light. The preliminary findings are intriguing, with the novel treatment resulting in some neurological and cognitive improvements. However, the small trial size implies further research is needed before anyone can claim that this therapy works.

According to the results of two recent small trials published in the journal PLoS One, an Alzheimer’s treatment is under development at MIT that alters patients’ brain waves using light and sound may be a safe approach to boost memory while preventing brain abnormalities associated with the disease.

These investigations are far too small to demonstrate the efficacy of the therapy. However, a much larger study is already underway to test this treatment option and might be completed by May 2025.

Brain Waves 101

About 86 billion neurons make up our brains, and these cells interact with one another using brief electrical pulses. When several neurons are activated, the pulses can synchronize and repeat in a systematic pattern, resulting in a rhythm known as a brain wave.

The brain generates five types of brain waves, classified based on their frequencies or how many times the cycle repeats every second. The frequency of delta waves is the lowest (0.5-4 Hertz), while the frequency of gamma waves is the highest (32–100 Hz).

Although our brains can produce more than one form of brain wave at a time, the dominant type is typically associated with alertness. For example, delta waves may predominate when you sleep, while gamma waves may predominate when you concentrate very hard.

What’s the idea behind the research?

Researchers have previously noted that those who have Alzheimer’s may have weaker and less synchronized gamma waves than those who do not. In a series of earlier investigations, scientists from MIT showed that exposing animals to 40 Hz clicking sounds or flickering lights could boost the strength and synchronization of these waves in Alzheimer’s mice models.

Together with their boosted gamma waves, the mice also appeared to have a range of benefits, such as memory enhancements, delayed neuronal degeneration, and decreased levels of proteins linked to Alzheimer’s in the brain compared to controls.

The researchers think this is because more powerful and in-sync gamma waves strengthen the neural connection, enlarge waste-clearing arteries, and improve immune cell responsiveness in the brain.

Evaluating the Safety and Effectiveness

The MIT researchers have completed two short clinical trials to see how the 40-Hz light and sound treatment, known as “Gamma ENtrainment Using Sensory stimuli” (GENUS), impacts people.

Two early-stage clinical studies evaluating the safety and effectiveness of 40-hertz sensory stimulation for Alzheimer’s treatment have found that the potential therapy was well-tolerated, had no notable adverse effects, and was associated with some considerable neurological and behavioral advantages in a small cohort of patients.

In a phase 1 trial, 43 participants, including 16 people with early-stage Alzheimer’s and two persons with epilepsy who were about to have brain surgery, received the 40-Hz GENUS treatment for a few minutes.

The team used scalp electrodes to track the activity of the participants’ frontal and occipital lobes before, during, and after the sensory stimulation. Activity in deeper brain areas that were reachable during surgery was evaluated in epilepsy patients.

According to the results, the strength of gamma waves in all brain areas seemed to rise throughout therapy, and gamma wave synchronization in the frontal and occipital lobes also increased. Sleepiness was the most often reported adverse event, and no other serious adverse events.

Home Therapy

In a phase 2a trial, the team provided GENUS devices to 15 individuals with early-stage Alzheimer’s to be used at home for an hour each day for at least three months. Each comprised a light panel linked to a speaker and video cameras to watch device usage.

They then randomly divided the participants into two groups and exposed eight of them to sound and light of 40 Hz frequency via the GENUS apparatus. White noise and steady light served as a sham treatment for the other seven.
At the start and end of the study, the subjects underwent cognitive testing, EEG recordings, and MRIs to quantify brain volume. Both groups’ users utilized the gadget around 90% of the time as instructed and reported no severe adverse effects.

The treatment group had a much greater connection between the areas of the brain associated with cognition and visual processing than the control group. They also fared much better on a memory assessment that challenged them to match faces with names.

Two metrics linked to Alzheimer’s progression — reduced hippocampal volume and raised ventricle volume — worsened in control participants but did not alter significantly in the treatment group. Yet, with only a few individuals in each group, it is hard to be confident in these results.

What’s Next?

While these trials imply that 40-Hz GENUS is safe and beneficial for Alzheimer’s patients, the sample sizes are far too limited to prove that sensory stimulation works.

Cognito Therapeutics, an MIT spinoff formed by senior author Li-Huei Tsai and co-author Ed Boyden, has already initiated a phase 3 trial in which they will randomly assign 500 persons with Alzheimer’s to receive daily 40-Hz auditory and visual stimulation or placebo treatment for 9 to 12 months.

If this more extensive experiment, dubbed HOPE, can demonstrate the treatment’s success, it could one day provide individuals with Alzheimer’s with a safer strategy to tackle the illness that does not put them in danger of grave side effects that some medications can cause.


  1. Chan, D., Suk, H.J., Jackson, B.L., Milman, N.P., Stark, D., Klerman, E.B., Kitchener, E., Fernandez Avalos, V.S., de Weck, G., Banerjee, A. and Beach, S.D., 2022. Gamma frequency sensory stimulation in mild probable Alzheimer’s dementia patients: Results of feasibility and pilot studies. PloS one, 17(12), p.e0278412.
  2. A Pivotal Study of Sensory Stimulation in Alzheimer’s Disease (Hope Study, CA-0011) (Hope). U.S. National Library of Medicine. Accessed: 5th April, 2023.
  3. 40HZz Rhythms Fight Alzheimer’s at the Cellular and Molecular Level. The Picower Institute for Learning and Memory. Accessed: 5th April, 2023.
  4. MIT is testing light and sound to combat Alzheimer’s. Freethink. Published online: 23rd Dec, 2023. Accessed: 5th April, 2023.
  5. First human trials test light & sound therapy for Alzheimer’s disease. New Atlas. Published online: 14th Dec, 2023. Accessed: 5th April, 2023.
Share with your friends!

Leave a Reply

Your email address will not be published. Required fields are marked *

home-icon-silhouette remove-button handshake left-quote check-circle user-icon