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Overview from TED

What if we could use brain waves to treat Alzheimer's? Professor and neuroscientist Li-Huei Tsai details a promising new approach to artificially stimulate gamma brain waves using light and sound therapy, to increase connectivity and synchrony and delay the onset of this deadly disease. This non-invasive therapy has already been shown to work in mice - now it's on to human clinical trials, with the potential to usher in a brighter future for everyone.

"I sometimes dream of a gamma society where we integrate gamma wave stimulation into our daily environment through our lighting or even our video entertainment."

White Brick Wall
Li-Huei Tsai

Professor, Neuroscientist

Li-Huei Tsai is the Picower Professor of Neuroscience at MIT and the director of the Picower Institute for Learning and Memory as well as the recipient of the Society for Neuroscience Mika Salpeter Lifetime Achievement Award and the 2018 Hans Wigzell Research Foundation Science Prize for her research on Alzheimer's disease.



Most of us know and love someone with Alzheimer's. It can be one of the hardest illnesses to watch affect a loved one. MIT neuroscience Professor Li-Huei Tsai is no exception. Except, unlike most of us, she has the scientific skill, dedication and innovation to think of a way to combat it.

How? With light and sound.

I have already written about how light technology is being used for new medical technologies and less invasive medical tools. The use of light is becoming commonplace in dermatology, dentistry and ophthalmology, due to its precision and high power density.

It seems deceptively simple, but the effects could dramatically alter the way we age. Around 50 million people experience dementia worldwide. In the UK 1 in 14 people over 65 have dementia and it is projected that 1.5 million people will be affected in 2040. Many people provide unpaid care for their loved ones currently, but it will be an enormous future social and economic cost.

“In the last 20 years, the Alzheimer's Association estimates deaths from heart disease declined by about seven percent. But the number of deaths from Alzheimer's disease increased 145 percent. One in three seniors in the US dies [from] Alzheimer’s disease or another dementia, they say. And more than 11 million people provide unpaid care for their loved ones with Alzheimer's.”

I was keen to see what Tsai would suggest. Given how prevalent Alzheimer's is, any treatment would need to be viable for a large population.


I had never imagined mice at a disco. I have now. Perhaps your mind too has conjured rollerblading mice, or some mice inventing new dance moves whilst others stick to ‘dad dancing’ classics.

No matter your imaginative skills, you are likely wondering why these mice were at a disco in the first place. It wasn’t for fun; the disco effects of flashing light and sound have been shown to benefit mice engineered to have Alzheimer's.

Tsai’s lab has shown how gamma brainwaves, those that synchronise brain activity to process new information for learning and memory, were affected by Alzheimer's:

“Indeed, my laboratory and others have shown that in people with Alzheimer's and in laboratory mice that model the disease, gamma waves at the frequency of 40 hertz have reduced power and synchrony….”

How to fix it? By giving them a little boost:

“By working with my colleagues, Emery Brown and Ed Boyden at MIT, we figured out that we could entrain or stimulate increased gamma waves by simply showing mice lights blinking at that frequency. This really works. Showing mice 40-hertz flickering light - and we demonstrated later, placing of 40-hertz buzzing sound - creates a 40-hertz disco that increases the power and synchrony of these waves across the brain. The effect reaches key parts of the brain, such as the prefrontal cortex, where we do planning and reasoning, and the hippocampus where we create memories.”

This disco had widespread benefits, including better performance on learning and memory tests than untreated mice:

“Mice exposed to gamma light and sound stimulation had major reductions in protein build-ups, amyloid plaques and tau tangles that are hallmarks of Alzheimer's progression. The stimulation preserved more of the connections or synapses that bind nerve cells into circuits. More cells survived, so the brain decayed less.”

Key hallmarks of Alzheimer's - amyloid plaques and tau tangle build ups - have recently been found to disrupt connections important for memory years before cognitive decline and diagnosis. So reducing build up is important, and if a short disco is useful then it could potentially be used as a preventative measure, before diagnosis.


Following these promising initial trials, pilot testing is underway on humans:

“We've developed a delivery device that our volunteers can use in their homes. It’s a poster-sized light box with a speaker underneath to produce synchronised 40-hertz sensory stimulation. A little tablet in the middle allows them to play videos when they are getting stimulated.”

I am amazed at how relatively easy this all seems. After all, most people have speakers, and tablets or devices that could play videos. Yes, these are specialised for the trial but it seems like a simple solution which would potentially not require hospital visits or in-patient treatment. Encouragingly, it appears to work:

“Annabelle Singer, a former member of our MIT team and now a professor at Georgia Tech, recently published encouraging results showing that gamma light and sound stimulation entrains stronger gamma waves in people. And their brains show increased connectivity and synchrony. My group has made some similar findings, including signs of preservation of brain volume and cognitive improvement. A private company we co-founded, Cognito Therapeutics, has also seen benefits in human testing, including reduced brain atrophy and improvement in mental functioning.”

It seems safe, is non-invasive, and has minimal side effects. It also wouldn’t add to the concoction of medication many elderly people take, which means it could probably be used in conjunction with this medication without needing to worry about how medications interact. 

Tsai is also testing to see if it could be used in a preventative manner to delay the incidence of Alzheimer's, as the reduced power of the gamma rays appears early. This could be massively beneficial considering the high proportion of adults facing the risk of Alzheimer's.

“I sometimes dream of a gamma society where we integrate gamma wave stimulation into our daily environment through our lighting or even our video entertainment. Maybe we will have a better world and a brighter future if we can keep our brainwaves, and therefore our mind and memory, well stimulated.”

I, for one, would be happy to integrate a little extra light and sound into my regular video viewing. Imagine if it was shown in TV adverts, or on YouTube adverts. It could become an app on our phones, with daily reminder notifications. The practical possibilities are virtually endless, and if it is as simple as it seems then it could affect the rate, and potentially age, at which Alzheimer's becomes debilitating. It would be revolutionary, and save a lot of heartache. 

Tsai agrees, and already uses her method every morning.

I look forward to the day we all incorporate a little of Tsai’s recommended disco into our lives - for fun, exercise and perhaps most importantly, our future minds.

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