The scientists at the Gwangju Institute of Science and Technology (GIST) in Korea demonstrated that there might be a way to combat AD by using "ultrasound-based gamma entrainment," a technique that involved syncing up a person's brain waves above 30 Hz (called "gamma waves") with an external oscillation of a given frequency.

An increase in average life expectancy in many parts of the world has made certain age-related diseases more common. Alzheimer's disease (AD), is one of them, being extremely prevalent within ageing societies in Japan, Korea, and various European countries. Currently, there is no cure or an effective strategy to slow down the progression of AD.

Fortunately, a recent study, published in 'Translational Neurodegeneration' by a team of scientists has shown a ray of hope. The process happens naturally by exposing a subject to a repetitive stimulus, such as sound, light, or mechanical vibrations.

Previous studies showed that gamma entrainment could fight off the formation of b-amyloid plaques and tau protein accumulations a standard hallmark of the onset of AD. In this recent paper, the GIST team demonstrated that it is possible to realise gamma entrainment by applying ultrasound pulses at 40 Hz, i.e., in the gamma frequency band, into the brain.

One of the main benefits of this approach was in the way it was administered. Associate Professor Jae Gwan Kim, who led the study alongside Assistant Professor Tae Kim, explained: "Compared with other gamma entrainment methods that rely on sounds or flickering lights, ultrasound can reach the brain non-invasively without disturbing our sensory system. This makes ultrasound-based approaches more comfortable for the patients."

As their experiments showed, exposure to ultrasound pulses for two hours daily for two weeks had reduced b-amyloid plaque concentration and tau protein levels in their brain. Furthermore, electroencephalographic analyses of also revealed functional improvements, suggesting that brain connectivity also benefited from this treatment. Moreover, the procedure did not cause any type of micro bleeding (brain haemorrhages), indicating that it was not mechanically harmful to brain tissue.

Overall, the promising results of this study could pave the way to innovative, non-invasive therapeutic strategies for AD without side effects, as well as help treat other conditions besides AD. Dr. Tae Kim remarked: "While our approach can significantly improve the quality of life of patients by slowing the progression of AD, it could also offer a new solution to other neurodegenerative diseases, such as Parkinson's disease."