Treating Dementia with Only 'Ultrasound Stimulation'?‥How Far Has It Come?[Reading Science]

[Interview] Professor Kim Tae of GIST Suggests Possibilities Through Animal Testing

Schematic diagram of an experiment that removes dementia-causing substances and improves brain activity in animal models through ultrasound stimulation. Image courtesy of Gwangju Institute of Science and Technology (GIST)

[Asia Economy Reporter Kim Bong-su] In December last year, a research team led by Professors Kim Tae and Kim Jae-kwan from the Department of Biomedical Engineering at Gwangju Institute of Science and Technology (GIST) attracted attention by suggesting the possibility of removing the causative substances of Alzheimer's dementia and improving symptoms through ultrasound stimulation. When ultrasound stimulation was applied for 2 hours a day to mice induced with Alzheimer's dementia, the causative substances decreased and connectivity between various brain regions improved, according to the research results. Professor Kim Tae (photo) stated in a written interview with Asia Economy, "So far, it is harmless to the human body, and we are currently working to verify safety and efficacy so that it can be used in actual clinical practice." Below is a Q&A with Professor Kim.

Professor Kim Tae, GIST.

- Please explain in detail the significance of this experiment.

△Research to reduce amyloid-beta, one of the causative substances of Alzheimer's disease, through auditory and visual stimulation at a 40Hz gamma wave frequency has been ongoing for over five years. This study is differentiated from previous research in that it directly stimulated the brain with ultrasound at a 40Hz rhythm instead of sound or light. Stimulating sensory organs with sound or light can cause discomfort itself, but ultrasound is at a frequency inaudible to humans, so it causes relatively less discomfort.

- What is the mechanism by which ultrasound stimulation causes such effects?

△Previous studies have reported that stimulating the brain at gamma frequency activates microglia, the immune cells in the brain, increasing their phagocytic activity. In other words, amyloid-beta is converted into a form that microglia can remove. Our experiment also confirmed the activation of microglia.

- Is it not dangerous to stimulate the human brain with 40Hz ultrasound?

△Ultrasound is widely used in medical diagnostics. However, in Alzheimer's disease, vascular pathology caused by amyloid-beta is common, raising concerns about bleeding. In this study, tissue examinations were conducted to check for microbleeding, and no increase in microbleeding was found, so no risk was detected. However, detailed research is needed to determine if this applies to humans as well.

- What are the challenges for future clinical use?

△For medical devices to be used clinically, safety and efficacy must be verified. Scientifically, research must precede to understand how ultrasound stimulation affects cells in the brain. Since ultrasound cannot pass through air, a medium such as water or gel is needed to transmit ultrasound between the device and the human body. These challenges must be resolved for actual clinical use.

- How long will it take until actual clinical use?

△At present, it is difficult to predict how much time will be needed.