Lack of deep sleep linked to build-up of Alzheimer's plaques in brain

A recently published study shines new light on the potential link between lack of deep sleep and the development of Alzheimer's disease. When it comes to the proper functioning of the brain's waste removal system, which works to clear out toxic proteins, not all sleep is the same. Deep sleep appears to be a key component in helping reduce one's chances of developing the disease, while lack of deep sleep may increase the risk.

Past research has implicated deep sleep — and lack thereof — as a factor when it comes to the development of Alzheimer's disease. At the heart of the matter are toxic proteins, including beta amyloid, which can accumulate in the brain. The accumulation of these proteins has been associated with Alzheimer's disease, and disrupted sleep may be a contributing factor.

The most recent study, which comes out of the University of Rochester, looked at the brains of mice that had been anesthetized with different anesthetic regimens. Of particular interest was the brain's glymphatic system, which involves cerebrospinal fluid used to essentially wash the brain of junk that would otherwise accumulate. Anesthetized mice with the strongest 'deep sleep' brain waves were more likely to have cerebrospinal fluid flow into the brain.

This system has previously been implicated as potentially having a role in the development of Alzheimer's disease — namely that it primarily works while we are asleep, and therefore a sleep disruption may negatively impact the glymphatic system's ability to eliminate these toxic proteins.

Talking about the research is co-director of the Center for Translational Neuromedicine and the study's lead author Maiken Nedergaard MD, DMSc, who said:

Sleep is critical to the function of the brain's waste removal system and this study shows that the deeper the sleep the better. These findings also add to the increasingly clear evidence that quality of sleep or sleep deprivation can predict the onset of Alzheimer's and dementia.