Khaberni - A team of scientists discovered a new method that could help fight Alzheimer's disease using low-frequency sound.
Recent research suggests that playing a low and steady humming sound at 40 Hz frequency - similar to the sound of a refrigerator - may stimulate the brain to remove harmful proteins associated with Alzheimer’s disease, which is the most common type of dementia.
In an experiment with aging monkeys, scientists at the Kunming Institute of Zoology in China played this sound for one hour daily over the course of a week. Tests showed that levels of "beta-amyloid" protein, responsible for forming harmful plaques in the brain, increased in the cerebrospinal fluid (fluid surrounding the brain and spinal cord), indicating that the protein was moved from the brain to the fluid for disposal. This effect continued for five weeks after the experiment ended.
This study builds on years of research conducted by scientists from the Massachusetts Institute of Technology (MIT), which showed that stimulating the brain at 40 Hz frequency organizes electrical activity and activates the brain's lymphatic system - the body's system for cleaning waste from the brain.
Professor Li-Huei Tsai, director of the Picower Institute for Learning and Memory at MIT, said, "Imagine the brain's lymphatic system as a car wash for the brain, where cerebrospinal fluid flows through the brain tissues carrying away waste, including proteins associated with Alzheimer's disease."
Professor Tsai and her team found that the brain's gamma waves, which pulse at the same 40 Hz frequency as the sound, play a key role in cleaning out harmful proteins. In Alzheimer's disease, these waves weaken, leading to the accumulation of proteins and damage to cells.
Previous research by Professor Tsai showed that stimulating the brain at this frequency reduces Alzheimer's proteins in mice and improves memory, while the new study showed a similar effect in primates, whose brains are quite similar to ours.
Meanwhile, Cognito Therapeutics has developed a home-use headset that emits sound and light at a 40 Hz frequency, and a previous trial found that using it for one hour daily over six months led to a slower decline in brain size and memory compared to users of a placebo device. A larger trial involving more than 600 patients is currently underway in the United States.
However, experts caution against using these devices at home before conclusive results are published. Professor Tsai says, "Final results on the effectiveness of 40 Hz stimulation for Alzheimer's patients have not yet been published."
The study also points to why elderly people benefit from hearing aids: hearing loss is a risk factor for dementia, and constant exposure to sound may help maintain normal brain rhythms. Some scientists are currently investigating integrating 40 Hz frequencies into earphones to provide continuous and non-intrusive stimulation.
