Science Friday - Could Light And Sound Therapy Treat Alzheimer’s?

Episode Date: August 20, 2024

A new potential Alzheimer’s therapy uses 40-hertz frequencies of light and sound to stimulate the brain. Research applying this treatment to mice showed a substantial decrease in amyloid plaques, a key biomarker for the disease, and an improvement in cognitive function. Clinical trials testing the efficacy of this method in humans are underway.But how exactly does this treatment work? Could it be a game changer in Alzheimer’s patients? And what potential does it have for other degenerative diseases, like multiple sclerosis?Ira talks with Dr. Li-Huei Tsai, professor of neuroscience and director of Picower Institute for Learning and Memory at the Massachusetts Institute of Technology, about her work developing this therapy.Transcript for this segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

A promising new Alzheimer's treatment uses light and sound to stimulate crucial brain waves. And it turned out that in Alzheimer's disease, the gamma waves are compromised. It's Tuesday, August 20th, and you're listening to Science Friday. I'm Cy Frye producer Shoshana Bucksbaum. An intriguing potential new Alzheimer's therapy. No, it's not a new blockbuster drug. The therapy uses 40 hertz frequencies of light and sound to stimulate the brain. brain. And research in mice showed a substantial decrease in amyloid plaques, a key biomarker for the

disease, and an improvement in cognitive functioning. And the technology is currently being tested for efficacy in humans. But how exactly does this treatment work? Here's Ira with more. Joining us now to talk about her work on this therapy is Dr. Lee Huay Tsai, Professor of Neuroscience, Director of the Peekhauer Institute for Learning and Memory at the Massachusetts Institute of Technology based in Cambridge, Massachusetts. Dr. Tsai, welcome to Science Friday. Thank you very much, Ira, for having me here today. You're quite welcome. Let's begin with some basic brain science. Your work stimulated brain waves in lab animals. What exactly is a brain wave? Brain waves happened when the nerve cells in our brain,

fire synchronously together. So this can be detected by electro and subalogram recordings, and then it will appear as waves or rhythms. And there are many different frequencies of this brain waves. And we are particularly interested in the so-called gamma waves. And we use 40 hertz light and sound stimulation to induce gamma waves in the brain. How does that happen? What is so special about these 40 hertz waves? Right. So the gamma waves has been known to be very important for higher order cognitive functions such as attention, sensory processing, learning, and memory. And it turned out that in Alzheimer's disease, both in human subjects and in animal models, the gamma waves are compromised.

So initially, we just wanted to boost gamma waves in the brain of Alzheimer's animal models to see whether this can improve either function or reduce pathology. And what did you find? Yeah, so our initial work, we were really surprised by the outcome, and this was done now almost a decade ago. We found that when we boost gamma waves using different approaches, and finally settling on using the very non-invasive, just gamma light and sound stimulation,

we found that very rapidly, like after an hour, the amyroid burden can already be reduced. And together, we also found other brain cell types show major changes, such as how they look and what kind of genes they express. So it seems that boosting gamma waves in the brain of Alzheimer's models has profound effect in the brain. Are you saying that the brain waves are able to help clear out these amyloid plaques and other junk in the brain?

Yes. So, in fact, from a recent study we just published about, about a month ago, we showed that increasing this gamma waves can profoundly increase a brain waste clearance mechanism. And this involved the bulk flow of the cerebral spinal fluid into the brain. And through this process, the metabolic waste and toxic waste in the brain can be cleared. almost like a car wash, you kind of flush the junk out of the brain. I didn't know we had a junk clearing system in our brain.

Yeah, this is really fascinating. And this mechanism is particularly active during sleep. By using this gamma light and sound stimulation, apparently we can reactivate this process and help clear the brain waste including beta amyloid. Do you know that it actually helps cognitive functioning in these mice? So we have worked with multiple Alzheimer's mouse models featuring either the amyloid pathology or the Tau Tengal pathology or a lot of neuronal deaths.

And in all of these models, we found that the light and sound stimulation, even chronically, meaning one hour per day for several weeks, this can lead to improvement of cognitive function. And in fact, now there are already smaller scale trials using the same approach in human subjects with Alzheimer's disease. And at least two different studies providing evidence that quantitative treatment can significantly, significantly slow the decline of cognitive function in Alzheimer's subjects. In human patients, you're saying? Yeah, in a small number of human patients in the early phase clinical studies.

Now, why can't I go out and get an audio generator, put my headphones on, turn it to 40 hertz, and then get a flashing light bulb that I can also tune to 40 hertz, and try this out on myself? Yeah, I mean, there are a lot of commercial products available right now. The problem is a number of the products have been really tested, either in animal models or in humans, to really prove that they can successfully increase the gamma waves in the brain or will have any effects in the brain. So I think that, you know, we have been working on this for many years, and we obviously tested many different conditions and optimize our devices. So I think that's important to bear it in mind.

Tell me then what it is like to undergo this therapy. Is it a headset a patient wears and the flashing lights? And do the light and the sound have to be coordinated to be in sync? So in our animal studies, we obviously, you know, we didn't use a headset. We basically sort of immerse the animals in 40-hertz light flickers and 40-hertz sun cleats. So they just stay in their home cage when they receive this light and sound stimulation. And for humans here at MIT, we conduct small-scale human studies. We have engineered our own devices, which is composed of L.E.

light box, which is filled with hundreds of LED light, and we programmed on to flash at 40 hertz. And we also provide auditory simulation to produce the 40 hertz sound clicks. So for this kind of device, we sort of place the light panel in front of the human subjects about five to six feet away. And all they need to do is just to turn the device on to receive the light and sound stimulation for an hour. I'm thinking of the potential, do you think any other diseases and any other illnesses, maybe brain illnesses might be useful here? So we do think that our approach has a potential to benefit other diseases.

We recently just published several scientific articles showing that the light and sound stimulation can very effectively induce malignation of our nerve fibers. So this malignation, they really serve us like insulation to protect the nerve fibers and also facilitate more rapid signal processing within the brain. And reduction of malignation is a feature of many neurological conditions such as multiple sclerosis. So we do think that with such a fundamental mechanism, this approach has the potential to help other diseases. You know, this seems to be so much cheaper than the thousands of dollars that the drug companies are spending or forcing you to spend on early Alzheimer's treatments that everybody who's going to be listening to us

is going to want to know how they can get either involved in this study or how soon will this be ready? Do you have an answer to both those questions? Right. So currently there is a MIT spin-off company, Cognito Therapeutics. They are conducting a phase three clinical trial on Alzheimer's disease. So they plan to treat Alzheimer's patients for one. year with one hour of stimulation every day. So hopefully from this trial, we will have some idea about how the therapy works in a larger population of Alzheimer's disease patients. You know, hopefully we will know the results soon and hopefully this can be available to many other people. You know, it's fascinating that you said this was a discovery of about 10 years ago,

how it almost sounds like it was discovered by accident and a serendipitous kind of way. Would that be correct? I mean, how somebody just discovered this works? Yeah, I would say this is precisely why doing scientific research is so fascinating and so exciting because a lot of time you would not expect that what you would get. and the surprises are just really, you know, very rewarding. So my lab is really a basic research laboratory. We would like to understand how the brain works, you know,

how learning a memory can be produced, and how this process is disrupted. And we found that the gamma waves are compromised in the early stage of the disease. So we simply ask a very straightforward question. You know, all we ask is if we have a way to boost gamma waves in the brain of the animal models, what will happen. So it all started from there. Wow.

Wow. This is quite interesting. And please let us know how this is working out, would you? Of course. Thank you, Ira. You're welcome. Dr. Li Hui Tsai, Professor of Neuroscience, Director of the Pekauer Institute for Learning and Memory. That's at MIT in Cambridge.

That's all the time we have for today. Lots of folks help make the show happen, including Emma Gomez, Sandy Roberts, Robin Casmer. Tomorrow, is it possible to build an elevator to space? We'll separate fact from science fiction. I'm sci-fi producer Shoshana Bucksbaum. Catch you next time.