Scientists are reporting success in using ultrasound to treat cognitive dysfunction in mice with simulated vascular dementia and Alzheimer's disease, which are the two most common forms of dementia. Applied to the whole brain, the ultrasound improved both the formation of blood vessels and the regeneration of nerve cells.

Led by cardiologist Hiroaki Shimokawa, a team at Japan's Tohoku University started with two groups of mice. One group underwent a surgical procedure that reduced blood flow to the brain, simulating the effects of vascular dementia, while the other group was genetically engineered to have an Alzheimer's-like condition.

Next, the scientists applied low-intensity pulsed ultrasound (LIPUS) to the brains of animals from both groups, in three 20-minute sessions per day. The vascular dementia mice received these thrice-daily treatments every other day for five days (for a total of three treatment days), and the Alzheimer's mice were subjected to 11 treatment days spaced over a period of three months.

When compared to control mice from both groups that didn't receive the LIPUS treatment, behavioural tests indicated that the treated mice showed significant improvements in cognitive function. Upon closer examination, it was found that the treatment caused an increase in the expression of an enzyme involved in the formation of blood vessels, along with an increase of a protein that plays a key role in nerve cell survival and growth. Importantly, there also appeared to be no side effects.

"The LIPUS therapy is a non-invasive physiotherapy that could apply to high-risk elderly patients without the need for surgery or anaesthesia, and could be used repeatedly," says Shimokawa.

These results back up the findings of an earlier study, in which a led team led by Shimokawa used heart-focused LIPUS to boost blood vessel formation in pigs suffering from myocardial ischemia, a condition in which blood flow to the heart is reduced.

It should also be noted that scientists from Australia's University of Queensland have previously used ultrasound to restore memory in genetically-engineered Alzheimer's mice, although in that case the ultrasound was used to remove toxic plaques in the animals' brains.

A paper on Shimokawa's latest study was recently published in the journal Brain Stimulation.