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Breakthrough in Alzheimer's Treatment?
Can regular treatment with sounds and light signals help alleviate the symptoms of Alzheimer's? A US research team has now found in a study that daily stimulation of the senses by light pulses and sounds improves memory and contributes to a significant breakdown of so-called amyloid plaques.
The researchers at the Massachusetts Institute of Technology (MIT) found in their current study that daily sensory stimulation with light and sound can alleviate the symptoms of Alzheimer's and thus reduce memory loss. The doctors published the results of their study in the English-language journal "Cell".
What is Alzheimer's?
Alzheimer's is one of the most common neurodegenerative diseases in the world. Around 1.3 million people in Germany suffer from the disease. Our brain cells are destroyed by Alzheimer's, which is connected with an ever increasing memory loss. Unfortunately, there is currently no cure for the disease and medical professionals can only slow it down. Various studies and clinical tests are currently underway, which are investigating around three dozen new active substances against Alzheimer's.
Studies have found positive effects from 40 Hertz flashes of light
A few years ago, the experts from the Massachusetts Institute of Technology (MIT) found that stimulating the senses with special light stimuli in mice with Alzheimer's causes some symptoms of the disease to be reduced. If the mice were exposed to 40 Hertz flashes of light, this was accompanied by a reduction in the amyloid plaques present in the visual center. Alzheimer's can not only affect the visual center, other regions of the brain are also affected, such as brain centers, which are very important for learning, memory and other higher thinking functions (e.g. the hippocampus and medial prefrontal cortex; mPFC). That is why it is important that stimulation also affects these parts of the brain, the experts say.
Effects of acoustic stimulation
The scientists first tested the effects of acoustic stimulation on the mice. Animals that were already suffering from Alzheimer's in the early stages were exposed to short sounds every 40 hours for a period of one hour. This led to noticeable changes after just one week: there was a significant improvement in memory functions, and the stimulation also seemed to have a positive effect on the brain. This was demonstrated, for example, by the fact that mice treated with sensory stimulation were better able to remember the position of a submerged platform in a pool of water compared to mice that were not treated. In addition, the treated mice recognized objects previously seen better.
A very clear change was also evident in the brain of the mice. Sound stimulation for a period of one week reduced the amount of plaques and beta-amyloid in the hearing center and in the hippocampus by 40 to 50 percent. This suggests that acoustic stimulation can also reduce the amyloid load outside of the primary sensory cortex. Other positive effects were that certain immune cells (microglia) increased by 60 percent through sound stimulation. Microglia are able to break down amyloid plaques. An expansion of the veins by 50 to 100 percent also enabled better blood circulation in the hippocampus and hearing center of the test animals in the study.
Combined treatment led to impressive success
The results were even more impressive when the sound stimulation was combined with the flashes of light previously examined. "When we combine visual and auditory stimulation for a week, we see an expansion of the positive effects on the prefrontal cortex and a very dramatic reduction in the amyloid," study author Li-Huei Tsai of the Massachusetts Institute of Technology said in a press release. Such a combined stimulation of the senses could be a promising approach for the prevention and treatment of Alzheimer's in the future. This form of sensory stimulation affects different brain cell types and different brain regions. “We have shown here that we can use a completely different sensory modality to induce gamma oscillations in the brain. This gamma induced by hearing stimulation can reduce the amyloid and tau pathology not only in the sensory cortex, but also in the hippocampus, ”continues study author Tsai.
What does the stimulation do in the brain?
The stimulation probably promotes the production of certain brain waves, which are referred to as gamma oscillations. These waves seem to have the positive effects. Unfortunately, the effects of stimulation do not last very long. When the daily treatment is stopped, the amount of plaques begins to increase again. It is therefore important that regular and permanent stimulation therapy is carried out.
Further investigations are necessary
Further research must now find out whether a combined light and sound stimulation is also effective in humans. Experiments with stimulation therapy have already been carried out on healthy human subjects in order to check the general tolerability of the treatment. The next step would now be tests on subjects with Alzheimer's. We are already looking for volunteers to participate. (as)