Flickering LED lights could help treat Alzheimer's

Boston: A unique visual stimulation with LED lights flickering at a specific frequency may substantially reduce the beta amyloid plaques seen in Alzheimer's disease, MIT scientists have found.

The treatment works by inducing brain waves known as gamma oscillations, which help the brain suppress beta amyloid production and invigorate cells responsible for destroying the plaques, according to the researchers who used the technique in mice. Further research will be needed to determine if a similar
approach could help Alzheimer's patients, said Li-Huei Tsai, professor at Massachusetts Institute of Technology in the US.

"It's a big 'if,' because so many things have been shown to work in mice, only to fail in humans," Tsai said. "But if humans behave similarly to mice in response to
this treatment, I would say the potential is just enormous, because it's so noninvasive, and it's so accessible," she said.

Alzheimer's disease is characterised by beta amyloid plaques that are suspected to be harmful to brain cells and to interfere with normal brain function. Previous studies have hinted that Alzheimer's patients also have impaired gamma oscillations. These brain waves, which range from 25 to 80 hertz (cycles per second), are believed to contribute to normal brain functions such as attention, perception and memory.

In a study of mice that were genetically programmed to develop Alzheimer's but did not yet show any plaque accumulation or behavioural symptoms, researchers found impaired gamma oscillations during patterns of activity that are essential for learning and memory while running a maze. They stimulated gamma oscillations at 40 hertz in a brain region called the hippocampus, which is critical in memory formation and retrieval.

Researchers came up with the idea of using light drive gamma oscillations in the brain. They built a simple device consisting of a strip of LEDs that can be programmed to flicker at different frequencies. Using this device, the researchers found that an hour of exposure to light flickering at 40 hertz enhanced gamma
oscillations and reduced beta amyloid levels by half in the visual cortex of mice in the very early stages of Alzheimer's.

However, the proteins returned to their original levels within 24 hours. The researchers then investigated whether a longer course of treatment could reduce amyloid plaques in mice with more advanced accumulation of amyloid plaques.
After treating the mice for an hour a day for seven days, both plaques and free-floating amyloid were markedly reduced. Researchers are now trying to determine how long these effects last. The study was published in the journal Nature.