Light and sound therapy for Alzheimer’s may also prevent ‘chemo brain’

An experimental treatment for Alzheimer’s disease that involves flickering lights and low-pitched sound may also help prevent cognitive problems after cancer treatment, sometimes called chemo brain, a study in mice suggests.

For Alzheimer’s disease, the light and sound stimulation has been shown to ease memory and concentration problems in small trials in people, but it is still being investigated in larger studies.

The lights flicker 40 times a second, or 40 hertz, with the sound also having a frequency of 40 Hz. This frequency was originally selected because people with Alzheimer’s have a lower intensity of 40 Hz brainwaves, which are linked with memory processing. The idea was that the treatment would stimulate these brainwaves.

Subsequent research suggests such brainwaves may result in broader benefits for the brain, including increasing the activity of immune cells and, most recently, boosting its drainage system, which could help clear a toxic protein called beta-amyloid.

Li-Huei Tsai at the Massachusetts Institute of Technology, who developed the approach, wondered if it could help people with cancer who experience memory and concentration problems after chemotherapy and other cancer treatments. It is thought these might be caused by damage to brain cells, but the exact mechanism is unclear and there are no treatments.

In the latest research, Tsai’s team found that cancer-free mice exposed to the lights and sounds for 1 hour a day while being dosed with a common chemotherapy drug called cisplatin showed less of a decline in mental sharpness than those who just got the chemotherapy.

Sharpness was assessed via a memory test that exposed the mice to objects that were either novel or familiar, with the animals usually showing more interest in items they haven’t seen before. Chemotherapy reduced the mice’s abilities to discriminate between the objects, but this was prevented by the light and sound treatment.

The therapy had several effects, including lowering brain inflammation, reducing DNA damage and lessening the loss of myelin, the insulation around nerve cell fibres.

Nazanin Derakhshan at the University of Reading in the UK says the idea needs to be tested in people to see if it provides an overall benefit. If the treatment were given at the same time as chemotherapy and it reduces cell death in the brain, that could promote the survival of cancer cells there, she says.