A cure for Alzheimer’s disease is like the crock of gold at the end of the rainbow – there’s a hazy outline in the distance but research never seems to get there.

Hundreds of drugs and chemical trials have hit dead ends over the last 20 years and now neuroscientist Li-Huei Tsai is trying a different approach, one not involving drugs at all. For the past three years, at the Massachusetts Institute of Technology, she has been experimenting with visual and auditory stimuli to the brain, using a combination of flashing lights and clicking sounds operating at certain frequencies to mimic the brain’s natural rhythm. The combination of the flashing light and clicking lights synchronise an electrical activity in the brain known as gamma waves. The aim is to stimulate electrical activity in the brain, potentially cleaning out toxins before they can build up. In 2019, at the end of a two-year gamma light therapy study this approach appeared to reduce neurodegeneration in Alzheimer’s-positive mice by reducing inflammation and cell death in the brain.

These gamma waves stimulate microglia cells, which act as cleaners in the brain. “They are like an immune surveillance,” Tsai said, “They survey the environment and they can clear away pathogens, toxic waste and foreign substances, and get rid of them.”

Previous findings have shown that microglia often do not function effectively in patients with Alzheimer’s, but the gamma waves seemed to reawaken them, leading to reduced levels of the protein deposits on the brain. Click here to read the current study on these proteins.

Other research supports Tsai’s findings. In a study at the University of Toronto, researcher Amy Clements-Cortes seated participants with Alzheimer’s in chairs with built-in speakers that released low-pitched sounds within the gamma frequency band. After six 30-minute sessions, significant improvements were noted in cognitive abilities. 

Looking to the future, Tsai said that studies with humans must be conducted very carefully with enough subjects and the correct controls and need to be conclusive. It could result in treatment being given with some sort of portable device that can consistently deliver the correct frequencies. Important factors need to be confirmed before a human trial takes place. “The first is to discover if 40 hertz light stimulation in human brains can train the neurons to fire gamma frequencies. We show it in mice.”

After reading about it, many people have written to Tsai saying that they were making a home device. She said, “I’m very worried about that because the wrong frequencies may be detrimental.’ Read more about it here, but definitely don’t try it at home!

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