A new study may have found the answer to a puzzling link between sleep and Alzheimer’s disease. Previous research has shown that people with Alzheimer’s often have sleep problems. Studies have also shown that people with sleep problems appear to be more vulnerable to Alzheimer’s. Until now, no one has been able to come up with a good explanation for this connection.
Laura Lewis, an assistant professor in the department of biomedical engineering at Boston University, and her team believe they may have found the explanation. It appears that the brain waves generated during deep sleep trigger a cleaning system that clears toxins from the brain. The results of their study has been published in the journal Science.
The team used MRI techniques and other technologies to observe the brains of 13 participants, aged between 23 and 33, in real time while they were sleeping. The team saw that during deep sleep – also known as non-rapid eye movement sleep – a flow of cerebrospinal fluid (CSF) rushed into the brain in pulsing waves every 20 seconds or so. Previous studies of animals found that an increased flow of CSF during sleep helps carry away waste products, including toxins, in the brain.
A toxin called beta-amyloid has been found to accumulate in the brains of people with Alzheimer’s. A previous study has shown that an increase in amyloid in the brain correlated with decreased sleep. It now appears that decreased sleep could result in more amyloid remaining in the brain, creating a vicious cycle.
The findings suggest people who get a lot of good quality sleep could protect themselves from cognitive decline. Scientists are already testing other lifestyle changes, like diet and exercise changes, in the fight to protect brain health. Sleep could be another weapon in the arsenal.