If you or someone you know has gone through chemotherapy, you might be familiar with the side effect commonly called 'chemo brain.' Scientists have now demonstrated a simple way to protect brain cells from damage using flashing lights and sounds at a certain frequency.
Chemotherapy is one of our best treatments for many cancers, but unfortunately its effects are felt throughout the body, including the brain. Patients often report 'brain fog,' where they have trouble with memory, concentration and decision making, affecting their thinking and behavior. While it normally goes away after the chemotherapy finishes, it can be a frustrating interruption to everyday life for a few months.
But a new study by Massachusetts Institute of Technology (MIT) researchers might have uncovered a fairly simple treatment to counter those ill effects – and, best of all, it’s less invasive than the chemo itself. All you have to do is look at some flashing lights and listen to some sounds daily.
Previous studies by the team have found that lights flickering at a frequency of 40 Hz, and sounds at the same pitch, can stimulate the brain to produce more gamma oscillations. These brain waves range from 25 to 80 Hz, and occur when you’re highly alert, aiding things like focus and concentration. Since people with Alzheimer’s disease seem to have problems with these gamma waves, the MIT team wondered whether this could form a simple treatment to improve their symptoms. And sure enough, experiments in mice showed reduced inflammation, lower levels of toxic proteins thought to contribute to neural degeneration, and improvements on cognitive tests after the light and sound therapy. For the new study, the MIT researchers turned their attention to a different ailment – chemo brain.
The team tested the treatment on mice with chemo brain, by giving them the common chemotherapy drug cisplatin for five days, then five days off, and five on again, mimicking the human dosage regime. Some received the 'gamma therapy,' involving an hour per day of exposure to 40-Hz light and sound, while the control group just had the chemo alone.
Three weeks later, the control mice showed many of the known brain effects of chemotherapy, including smaller brain volume, DNA damage, inflammation, and damage to myelin, the protective coating around neurons. Their populations of brain cells that produce myelin, called oligodendrocytes, were also reduced.
However, the mice that received daily gamma therapy for the duration of their chemotherapy showed significant reductions in all of these symptoms. They also performed much better on tests that measure the animals’ memory and executive function. When the researchers analyzed gene expression, they found that genes linked to inflammation and cell death were suppressed in mice treated with gamma therapy.
“The treatment can reduce DNA damage, reduce inflammation, and increase the number of oligodendrocytes, which are the cells that produce myelin surrounding the axons,” said Li-Huei Tsai, senior author of the study. “We also found that this treatment improved learning and memory, and enhanced executive function in the animals.”
The benefits were found to persist, at least partially, for up to four months after treatment. Gamma therapy was found to work much better if administered at the same time as the chemotherapy, rather than starting it afterwards. Follow-up studies found similar positive effects in mice receiving a different chemo drug, methotrexate. While the mouse tests involved brain implants to directly deliver light and sound to neurons, previous human trials for Alzheimer's have shown similar benefits can be achieved using just a synchronized screen and speaker setup. If it works, this could become a standard part of administering chemotherapy to human patients, to make the life-saving treatment less uncomfortable.
The team also plans to test gamma therapy against other neurological diseases, like Parkinson’s and multiple sclerosis. Clinical trials in human Alzheimer’s patients are already underway.
The research was published in the journal Science Translational Medicine.
Source: MIT