Could Light And Sound Therapy Treat Alzheimer’s?

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, forest walking– we’ll share some ways to connect with nature. Plus, is it possible to finally build a space elevator? But, first, an intriguing, potentially new Alzheimer’s therapy and, no, it’s not a new blockbuster drug.

The therapy uses 40-hertz frequencies of light and sound to stimulate the brain. And it seems to work– at least in mice. Research in mice showed a substantial decrease in amyloid plaques. That’s a key biomarker for the disease and an improvement in cognitive function. And the technology is currently being tested in humans.

But how exactly does this treatment work? And could it be a game changer in Alzheimer’s patients? Joining us now to talk about her work on this therapy is Dr. Li-Huei Tsai, professor of neuroscience, director of the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology based in Cambridge, Massachusetts. Dr. Tsai, welcome to Science Friday.

LI-HUEI TSAI: Thank you very much, Ira, for having me here today.

IRA FLATOW: You’re quite welcome. Let’s begin with some basic brain science. Your work stimulated brainwaves in the lab animals. What exactly is a brainwave?

LI-HUEI TSAI: Brainwaves happened when the nerve cells in our brain fire synchronously together. So this can be detected by electrode electroencephalogram recordings. And then it will appear as waves or rhythms. And there are many different frequencies of this brainwaves. 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.

IRA FLATOW: How does that happen? What is so special about these 40-hertz waves?

LI-HUEI TSAI: 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 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.

IRA FLATOW: And what did you find?

LI-HUEI TSAI: 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 noninvasive, just gamma light and sound stimulation, we found that very rapidly– like after an hour– the amyloid 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.

IRA FLATOW: Are you saying that the brain waves are able to help clear out these amyloid plaques and others other junk in the brain?

LI-HUEI TSAI: Yes. So, in fact, from a recent study we just published about a month ago, we showed that increasing this gamma waves can profoundly increase a brainwave’s clearance mechanism. And this involved the bulk flow of the cerebrospinal fluid into the brain. And through this process, the metabolic wastes and toxic wastes in the brain can be cleared almost like a car wash. You flush the junk out of the brain.

IRA FLATOW: I didn’t know we had a junk-clearing system in our brain.

LI-HUEI TSAI: 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.

IRA FLATOW: Do you know that it actually helps cognitive functioning in these mice?

LI-HUEI TSAI: So we have worked with multiple Alzheimer’s mouse models, featuring either the amyloid pathology, or the tau tangle pathology, or a lot of neuronal death. And in all of these models, we found that the light and sound stimulation given 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. At least two different studies provide the evidence that chronic treatment can significantly slow the decline of cognitive function in Alzheimer’s subjects.

IRA FLATOW: In human patients, you’re saying?

LI-HUEI TSAI: Yeah, in a small number of human patients in the early phase clinical studies.

IRA FLATOW: 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?

LI-HUEI TSAI: Yeah, I mean, there are a lot of commercial products available right now. The problem is none 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 we have been working on this for many years, and we obviously tested many different conditions and optimized our devices. So I think that’s important to bear in mind.

IRA FLATOW: 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?

LI-HUEI TSAI: So in our animal studies, we– obviously, we didn’t use a headset. We basically immerse the animals in 40-hertz light flickers and 40-hertz sound clips. 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 LED light box, which is filled with hundreds of LED light and we programmed them to flash at 40 hertz. And we also provide auditory stimulation to produce the 40-hertz sound clicks. So for this kind of device, we place the light panel in front of the human subjects about five to six feet away. And all they need to do is just turn the device on to receive the light and sound stimulation for an hour.

IRA FLATOW: I’m thinking of the potential. Do you think any other diseases and any other illnesses, maybe brain illnesses, might be useful here?

LI-HUEI TSAI: So we do think that our approach has the potential to benefit other diseases. We recently just published several scientific articles showing that the light and sound stimulation can very effectively induce myelination of our nerve fibers. So this myelination– they really serve as an insulation to protect the nerve fibers and also facilitate more rapid signal processing within the brain. And reduction of myelination 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.

IRA FLATOW: 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?

LI-HUEI TSAI: Right. So, currently, there is an MIT spin-off company– Cognito Therapeutics. They are conducting a phase III 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 the larger population of Alzheimer disease patients. Hopefully we will know the results soon and hopefully this can be available to many other people.

IRA FLATOW: It’s fascinating that– you said this was a discovery about 10 years ago– how it almost sounds like it was discovered by accident in a serendipitous kind of way. Is would that be correct? I mean, how somebody just discovered this works?

LI-HUEI TSAI: Yeah, I will say this is precisely why doing scientific research is so fascinating and so exciting because a lot of time would not expect that what you would get and the surprises are just really very rewarding. So my lab is really a basic research laboratory. We’d like to understand how the brain works, how learning and 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 asked a very straightforward question. 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.

IRA FLATOW: Wow. Wow. This is quite interesting. And please let us know how this is working out, would you?

LI-HUEI TSAI: Of course. Thank you, Ira.

IRA FLATOW: You’re welcome. Dr. Li-Huei Tsai, professor of neuroscience, director of the Picower Institute for Learning and Memory. That’s at MIT in Cambridge.

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