BEIJING, Jan. 8, 2026 (Xinhua) – A team of Chinese scientists has discovered that a simple, non-surgical sound therapy can produce noticeable and long-term biological changes in elderly monkeys, opening new horizons for a possible physical treatment for Alzheimer’s disease.
The results of the study, led by researchers from the Kunming Institute of Zoology of the Chinese Academy of Sciences, were published in the latest issue of the journal Proceedings of the National Academy of Sciences.
The study focuses on using an auditory tone with a frequency of 40 Hz, which is a low tone that falls within the range of human hearing. While previous studies in mice have suggested that 40 Hz stimulation may help remove toxic proteins associated with Alzheimer’s disease from the brain, this new study provides the first conclusive evidence in a study conducted in non-human primates.
In Alzheimer’s disease, a protein known as beta-amyloid tends to accumulate in the form of plaques, which leads to damage to brain cells and impairs memory and cognitive abilities. The brain usually gets rid of these wastes through the cerebrospinal fluid.
The research team worked on nine elderly rhesus monkeys, whose brains naturally develop plaques similar to those associated with Alzheimer’s disease, making them highly relevant models for studying the condition in humans. The monkeys listened to a 40 Hz tone for one hour daily for a week.
The results were amazing, as levels of key proteins associated with Alzheimer’s disease in the monkeys’ cerebrospinal fluid more than doubled immediately after the end of the treatment period, which means the process of eliminating waste was enhanced.
“It is worth noting that this effect persists,” said Hu Xintian, a researcher at the Kunming Institute of Zoology. “When measured five weeks after the end of sound therapy, the benefit had not faded away.”
He explained that currently approved drug treatments for Alzheimer’s disease, although effective in some patients, may entail risks such as brain swelling, in addition to their high cost, while 40 Hz auditory stimulation represents a safe and low-cost physical intervention.
“The long-term effect we observed in primates supports the development of this gentle approach as a future treatment for Alzheimer’s disease,” he added.