Scientists at the Kunming Institute of Zoology (KIZ) of the Chinese Academy of Sciences have shown for the first time in non-human primates that sound stimulation at 40-Hz can significantly increase β-amyloid levels in the cerebrospinal fluid (CSF) of aged rhesus monkeys. Notably, this effect lasted for more than five weeks after treatment ended.

The findings, published in PNAS, provide the first experimental evidence in non-human primates that 40-Hz stimulation could serve as a non-invasive physical approach for Alzheimer’s disease (AD). The study also highlights important differences between primate and rodent models, which are often used in preclinical research.

Led by Dr. Xintian Hu at KIZ, the research team worked with nine elderly rhesus macaques (Macaca mulatta) between 26 and 31 years old. These monkeys naturally developed widespread amyloid plaques in their brains, closely resembling the Aβ pathology seen in human AD. Because of this similarity, they offer a valuable model for testing potential therapies before moving to human trials.