Every morning Li-Hui Tsai meditates in front of a flickering screen. Synchronously with the flashes of light, sharp sounds are heard, somewhat reminiscent of the clicks of the castanets of a flamenco dancer, only much louder. However, the rhythm here is not for fun.
The combination of flickering light and clicking sounds helps synchronize electrical processes in the brain known as gamma waves.
For the uninitiated, this sound and light treatment may seem like a new fad for wellness fans. But Tsai is a neurophysiologist from the Massachusetts Institute of Technology (Cambridge, USA). And she has evidence that this procedure can prevent the development of Alzheimer's disease.
Li-Hui Tsai's research is a radical new approach to preventing and treating the most common form of senile dementia.
Today, about 50 million people worldwide suffer from dementia - and this figure is expected to triple by 2050.
From a neuroscience perspective (according to the prevailing hypothesis - Ed.), The main change associated with Alzheimer's is the accumulation of toxic proteins in the brain (amyloid plaques) and the formation of tau protein clusters within neurons.
As a result, both processes seem to wreak havoc in our neurons and their synapses (the contact points between two neurons that allow them to "talk").
So it's no surprise that over the past three decades, much of Alzheimer's research has focused on finding cures to remove these plaques - and yet we're still waiting for a breakthrough.
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And now a series of new studies suggests that the answer may not be chemical, but electrical.
And it all depends on those gamma rhythms that seem to trigger some kind of cleansing operations in the brain, removing toxins before they begin to cause harm.
Healing Brain Waves
In everyday life, we often use the word "dawned" when it comes to a sudden surge of inspiration. In neurophysiology, what dawns on us is special waves in the brain, a rhythmic pattern of electrical activity created by groups of neurons throughout the brain at a specific frequency.
In the same way that radio or television stations transmit their signal on a particular wavelength, different frequencies of brain waves seem to be related to very specific neurological functions.
Gamma waves oscillate about 30 to 100 times per second and can usually be seen when we are concentrating on something or trying to remember something.
In some very interesting studies of the early 2000s, it was demonstrated that patients with Alzheimer's are especially weak, in particular, gamma waves, the fastest brain rhythms (compared with healthy people without signs of decline in mental abilities), which suggests that a violation of these rhythms can be implicated in the disease.
However, it was not clear: whether this is just another consequence of the already onset general neurodegeneration, or - potentially - its cause. And a team of scientists led by Tsai decided to figure it out.
To prove their hypothesis in principle, they first resorted to a technique known as optogenetics, in which the neurons of a laboratory mouse are genetically altered to respond to light of a specific color.
By placing a tiny light source in an animal's skull, scientists can stimulate gamma waves with very high precision and observe the effects.
Guarding the Brain
And what they saw was amazing. Not only was there a significant reduction in amyloid plaques. Researchers discovered the mechanism of their creation.
Especially interesting was the effect on the microglia of the brain (macrophage cells, a kind of emergency rescue team, bodyguards of our brain, taking care of its health).
“They are like immune surveillance,” Tsai explains. "They monitor the environment and can clean out pathogens, toxic waste and foreign substances."
Previous studies have found that in patients with Alzheimer's, microglia are often unable to perform their duties properly. But it seems that gamma waves can wake up macrophage cells, which leads to a decrease in the number of amyloid plaques and tau protein clumps.
Moreover, the effect of using gamma waves comes very quickly. Just one hour of stimulation was enough to activate the microglia and achieve a noticeable reduction in the number of amyloid plaques.
This effect of gamma waves on macrophage cells represents a huge leap forward in our understanding of Alzheimer's disease (and the function of gamma waves), Tsai said.
Optogenetic stimulation, however, is a procedure that is not easy to apply in humans. So in the next step, Tsai tried to test whether less invasive forms of brainwave synchronization would work.
In one experiment, scientists illuminated mice every day for an hour with flickering light at a frequency of 40 Hz, while in other experiments, animals heard rapid clicking sounds at this frequency.
And in each of the cases it worked, there was synchronization. Macrophage cells worked more actively, the level of toxic proteins decreased.
It is also important that all this affected the behavior of the mice. Those who received stimulation found a way out of the maze faster and remembered it better - in contrast to those who grew old without stimulation.
Beneficial vibrations
But will scientists be able to replicate these results in real-life Alzheimer's patients?
Tsai is now embarking on clinical trials to investigate the long-term benefits of gamma-wave stimulation for humans.
But another study has already found some encouraging evidence that such stimulation does lead to improved cognitive performance.
The study, led by Amy Clements-Cortes of the University of Toronto, Canada, used tactile stimulation as well as auditory stimulation. Participants with diagnoses of different stages of Alzheimer's disease sat in a chair with six speakers that emitted low sounds at the frequency of gamma waves.
It was reminiscent of the action of a subwoofer (low frequency speaker), Clements-Cortez says, causing the participants to feel light vibrations throughout their bodies.
After six 30-minute sessions, the patients showed improvements in standard tests for various cognitive abilities, including mental counting and short-term memory.
This was especially surprising when you consider how short the stimulation interval was, notes Clements-Cortez.
She also has testimony from another patient with mild signs of dementia who has been using a similar device at home for three years. “Three years later, we came to visit her,” says Clements-Cortes. "Her mental abilities have not deteriorated, they have remained about the same."
It is clear that much more data needs to be collected, with larger samples, but the initial results, according to Clements-Cortes, are "incredibly inspiring."
It is possible that patients will be able to receive this type of therapy simply by watching TV or listening to the radio, she says.
After so many years of fruitless attempts to find a cure for Alzheimer's, a light has finally dawned at the end of the tunnel?
It appears that the new method may be particularly valuable for early intervention during the course of the disease.
Martin O'Halloran of the National University of Ireland points out that although patients may have cognitive difficulties, it takes a long time to confirm the diagnosis of Alzheimer's, and this delays the initiation of treatment, since doctors are unwilling to risk side effects until they are sure of the diagnosis. …
“Any early intervention for these patients should be as non-invasive and safe as possible,” he says. “Including using flickering light or repeating sound.” (For patients with epilepsy, this is not suitable, as stimulation can trigger a seizure.)
Barry McDermott, a researcher at the National University of Ireland, is also optimistic about the findings.
“No doctor will prescribe Alzheimer's medications for prevention, but this method is something that you can start using in advance,” he notes. - It is so simple and light. In theory, you could even have such an app on your smartphone.”
Despite rapid advances in research, both O'Halloran and McDermott, who recently reviewed the potential of the technology for the Journal of Alzheimer's Disease Research, emphasize that many questions remain to be answered.
In addition to the need to obtain more serious confirmation of the long-term usefulness of the method in clinical trials, it is also necessary to understand what frequency of gamma waves is ideal for use and what is the optimal duration of use.
While it seems unlikely that you will get an overdose of gamma waves, it will be helpful to see if excessive enthusiasm for the method will cause side effects, the Irish scientists emphasize.
In addition, it remains to be seen whether stimulation of gamma waves improves the mental capacity of healthy people.
Tsai is careful here: she believes that there is a certain limit to what gamma waves can do for a healthy brain.
But she hopes the method can be useful as a preventative measure after a person has passed middle age - to keep the brain functioning normally before the first signs of mental decline appear. “I think it's possible,” she says.
Despite many questions that remain to be answered, Tsai is already testing the device on himself. “And I feel great,” she says with a sly smile.
Like any scientist, Li-Hui Tsai understands that her personal experience cannot be taken as conclusive evidence. However, if the results of her research are confirmed, many of us may well start our day with similar sound and light treatments - to keep our brains healthy.
David Robson