Treating Alzheimer’s with Flickering Lights and Not So Banging Music

By Dr. Hira Shaheen

Alzheimer’s is one of the most common neurodegenerative problems among the elderly. It affects the learning, memory, and other higher brain functions of the affected individual.  The underlying mechanism of Alzheimer’s involves the accumulation of a particular proteins, β-amyloid and tau, in your brain.

Most people with Alzheimer’s need assistance with remembering daily tasks and maintaining coordination. However, despite being significantly debilitating in nature, Alzheimer’s remains incurable.

In 2016, a team of researchers at the Massachusetts Institute of Technology (MIT) performed an animal-based study using visual gamma light stimulation. It proved that visual stimulus of gamma oscillations (invasive and non-invasive both) effectively alleviates Alzheimer’s in the visual cortex of the brain. In recent years, the same team has expanded its research scope to multi-sensory gamma stimulation. It couples auditory and visual stimuli and findings are revolutionary. Perhaps, you won’t look at jingle bells or Christmas lights the same way after reading them!

How Do Gamma Stimuli Relate With Human Brain?

Your brain has complex neuronal networks that communicate through electrical signaling. The synchronized firing of neurons generates rhythmical patterns in the brain in the form of waves.  For instance, when you are in a relaxed mental state, your brain generates alpha waves.

Similarly, gamma waves occur during activities related to cognition, memory, and learning, such as navigating a new city. Their frequency is more than 30Hz, but individuals with Alzheimer’s have scarce gamma oscillations in their brains.

The MIT team increased these gamma oscillations through external stimuli to see the results.

How Do External Gamma Oscillations Using Sensory Stimuli Attenuate Alzheimer’s?

During the 2016 study, the researchers exposed rats, with aggregates of amyloid-β in their brains, to an LED light in a gamma entertainment using sensory stimulation (GENUS) unit. The frequency of flickering light was 40Hz, and they found a fifty percent reduction in amyloid-β accumulation.

The follow-up research combines visual and an auditory stimulus to observe potential amplification of the results with a different sensory modality. It also sets out to investigate the scope of gamma oscillations beyond the sensory areas of the brain.

In the multi-sensory study, light and sound are used simultaneously on the subjects. An auditory tone of 40Hz activates the cortical area of the brain.

Your brain has an auditory cortex in the temporal lobe responsible for processing input from the ear. The oscillations of a particular frequency influence signaling in this area, which becomes apparent due to an increase in its blood flow and brain wave generation.

The findings of a multi-sensory approach are encouraging. The researchers have observed that exposure to multi-sensory gamma oscillations for seven days leads to better recognition and spatial memory. The amyloid load also reduces significantly in the hippocampus and various other brain regions.

 The scientists explain the following mechanisms being responsible for these results:

#1 It Activates An Immune Response In Brain

Gamma oscillations activate microglia cells. These are like housekeepers of your brain, mainly involved in janitorial duties. Their activation leads to better waste management in the brain, including the elimination of amyloid proteins. The auditory or visual stimulation alone can adequately push them to perform a rapid cleaning action. Gamma oscillation entertainment using sensory stimuli (GENUS) increases the size of the soma of microglia cells and boosts their phagocytic activity. However, with a multi-sensory approach, this effect becomes exponential.

The combined stimulation GENUS results in higher quantity and better organization of microglia cells surrounding the amyloid plaques. They profusely cluster around amyloid-β proteins in comparison with single stimulus GENUS. This crowding increases the cleaning ability and enhances the protein load reduction.

Alzheimer’s affects numerous brain areas, which makes it particularly challenging to deal with. Since the multi-sensory approach extends cleaning process beyond the sensory areas, its influence is wide-ranged. It is particularly important in terms of cortical areas, where visual gamma oscillations stimulus alone does not seem to work. The auditory GENUS clears plaques from auditory cortex, hippocampus, and medial prefrontal cortex.

#2 It Reduces Tau Phosphorylation In Brain

Besides amyloid-β, the neurodegenerative brain faces a disruption in tau proteins. The abnormality lies in excessive tau phosphorylation at the specific amino acid sequences in Alzheimer’s.

Auditory gamma oscillation exposure promotes phosphorylation of tau at the level of serine and threonine amino acids. This mechanism proves significantly rehabilitative and reduces the hyper-phosphorylation process of tau- a hallmark of Alzheimer’s pathology.

It is interesting to note that visual gamma stimulation alone also has a similar effect. Therefore, combining these two maximizes the effort and translates into superior cognitive outcomes.

#3 It Increases Vascular Clearance of Abnormal Proteins

Multi-sensory gamma entertainment also triggers astrocyte activity in your brain. These are types of glial cells, but their function of clearance involves blood flow. Most astrocytes surround brain vessels and even act as bridges between neurons and the vascular networks in the brain.

The auditory stimulation increases the blood flow of the auditory cortex through vascular dilatation. It allows astrocytes to dump waste in these opened-up pipelines. Therefore, they use this connection for an additional clearance pathway, escalating the process of amyloid load reduction. 

The Caveats

The effects of multisensory gamma stimulation are evident on the pathology of Alzheimer’s. However, their extent of materialization in humans needs further investigation. The conversion of Alzheimer’s technologies from animal models to humans is always challenging, but the MIT team is hopeful, and human trials for safety are underway.

Another interesting finding is that the effective frequency range is remarkably narrow. Scientists have tried various lower and higher frequencies, but the frequency of 40Hz seems to be the only sweet spot. The reason for this is still a mystery, though.

The Way Forward

Scientists speculate that there is still a potential missing link in the understanding of the complete mechanism involved in cognition improvement. We do not know how a decrease in protein accumulation translates into better focus. Moreover, the permanence of these changes is also questionable. For now, repetitive stimulation is imperative for constant relief. Perhaps in the future, we may be able to find a way to sustain these gamma oscillations for a long time.

There is also an emerging interest in using such technologies to extensive memory processing because Alzheimer’s has severe progressive dementia. Hopefully, these researches will open doors for exploring further possibilities and finding therapies to alleviate symptoms of Alzheimer’s.