Every day, individuals like Joan are retreating into their homes to experience rhythmic clicking and flashing lights, tuned to repeat 40 times a second. This immersive audiovisual experience aims to synchronize particular electrical patterns called gamma waves in the brain, with the goal of combating the effects of dementia. After a year of this routine, scans showed that Joan’s brain volume had remained stable and memory tests found that her cognitive decline had stopped as well.
The Science Behind Gamma Stimulation
Alzheimer’s disease is characterized by the accumulation of amyloid-β plaques and tau tangles in the brain, interfering with neuronal communication and resulting in cell death. However, researchers discovered a deficiency in gamma frequency band waves, which oscillate at around 40 hertz, in individuals with Alzheimer’s disease. These gamma waves are crucial for processes such as attention and memory.
Li-Huei Tsai and her colleagues at MIT induced gamma waves in mouse brains using genetic modification and optical fibers. They then developed less invasive methods, such as strip lights, mini sound systems, or vibrating subwoofers. The rhythmic cues engage the brain through sensory on-ramps, areas in the cortex responsible for processing sensory information. From there, the gamma signal spreads to deeper brain regions, such as the hypothalamus, that play key parts in memory and cognition.
With repeated exposure comes brain entrainment: the firing patterns of neurons start to align with the rhythm of the stimulus. Synapses strengthen, inflammation subsides, and 40-hertz stimulation also activates a neural-cleansing mechanism in mice, in which cerebrospinal fluid enters the brain, collects molecular debris, and exits through specialized waste-removal channels.
Clinical Trial Data and Potential Benefits
Academic studies by the teams at MIT and Emory, along with industry-sponsored trials by Cognito researchers, have collectively found that 1–6 months of 40-hertz stimulation with both light and sound, delivered at home for an hour a day, can boost cognition, preserve brain volume, improve sleep quality, enhance the ability to do everyday tasks, and induce favorable changes in brain immunity.
In one of the longest studies of its kind, participants' test scores have remained stable, brain volumes have shown no signs of shrinking, and levels of a disease-associated protein in the blood have even trended downwards. At an international conference, Cognito reported similar benefits in both brain structure and cognitive function during 18 months of treatment with the company’s wearable technology.
Concerns and the Path Forward
Despite the encouraging data, some researchers have not been able to replicate the findings in mice. Methodological differences between these studies and the original MIT report might explain the conflicting results. Some developers have already started marketing similar devices as holistic health aids, arguing that the technology is safe and that individuals can experience its potential cognitive benefits without the need for formal regulatory approval.
The lack of regulation and quality control worries some researchers, who have found that commercial devices often fail to consistently deliver 40-hertz flickers. They also warn that side effects such as headaches occur in an appreciable fraction of users, and for those prone to seizures, the flashing lights could pose serious risks.
Cognito is conducting an extension study, allowing participants the opportunity to continue therapy for a further 12 months. The company has been purposeful about developing a very robust evidence base for its device ahead of seeking marketing authorization, probably by early 2026.
