Skimping on sleep may put people at higher risk for accumulating the protein plaques in the brain involved in Alzheimer’s disease. NPR Shots reported from Thursday’s edition of Science that brain waves generated during deep sleep appear to trigger a brain cleaning system that protects it against Alzheimer’s and other neurodegenerative diseases.
Alzheimer’s affects the brain by destroying neurons (special cells responsible for information processing and transfer) initially in areas of the brain related to memory and later in areas used for language, reasoning, and social behavior. There is currently no cure; a few medications are approved which regulate chemical messengers in the brain, but ultimately Alzheimer’s is a progressive and fatal disease.
A group of biomedical engineering researchers at Boston University were studying the brains of sleeping people using MRI and noticed large, slow waves of cerebrospinal fluid (CSF) washing over the sleepers’ brains about every 20 seconds. CSF comes from blood plasma and is distributed throughout the central nervous system, and the scientists noticed that each wave was immediately preceded by a spike of electrical activity in the neurons.
These slow waves appear when a person enters the state known as deep sleep, or non-rapid eye movement sleep, and they play a role in both memory and brain disease, according to the team.
“It’s already known that people with Alzheimer’s disease have less of these electrophysiological slow waves, so they have smaller and fewer slow waves,” says Laura Lewis, a professor involved in the study. Fewer waves means fewer wash cycles in the brain, which would limit the brain’s ability to clear out the toxins associated with Alzheimer’s.
The finding also suggests that people might be able to reduce their risk of Alzheimer’s by ensuring that they get high-quality sleep, says William Jagust, a professor of public health and neuroscience at the University of California, Berkeley, who was not involved in the study.
The team cautions that there are a number of factors likely involved in Alzheimer’s disease and this study included only 11 people, but so far sleep should be high on our list of healthy lifestyle choices, especially as we age.