Poor sleep in old age may be linked to the brain-clogging plaques thought to contribute to Alzheimer’s disease, new research suggests.
“Sleep appears to be a missing piece in the Alzheimer’s puzzle, and enhancing sleep may lessen the cognitive burden that Alzheimer’s disease imparts,” said study author Bryce Mander, a postdoctoral fellow at the University of California, Berkeley.
It’s not clear how sleep and memory affect – or are affected by – the accumulation of beta amyloid plaques, believed to interfere with mental functioning. Still, the study findings hint at a major message regarding Alzheimer’s, said Mander, who works at the university’s Sleep and Neuroimaging Laboratory.
For the new study, Mander and colleagues recruited 26 mentally healthy adults ages 70 to 79. They underwent brain imaging to assess plaque buildup, and were asked to remember pairs of words before and after a night’s sleep. Overnight, researchers measured their brain waves, and the next day they conducted MRI scans during the memory testing.
Those patients with the highest levels of amyloid plaques in one part of the brain – the medial prefrontal cortex – had lighter sleep and higher levels of memory problems, the researchers found.
“It is not so much that memory after sleep is important, but that sleep after initial learning is important to help us retain memory for a longer period of time,” Mander said.
The study suggests – but does not prove – that insufficient deep sleep contributes to “a reduced ability to cement memories in the brain over the long-term, resulting in greater memory loss,” he noted.
However, he added, it’s not known for sure “whether this link between sleep and Alzheimer’s disease can explain memory loss in older adults” with higher levels of the plaques.
Sleep disorders are frequently reported in Alzheimer’s patients, noted one expert. And poor sleep throughout life appears to boost the risk of Alzheimer’s disease.
The study was published in the June 1 issue of Nature Neuroscience.
Sleep quality is an excellent measure of general health. The physical body requires only 3 hours of sleep per night to rejuvenate. However, the brain requires more than double that amount. As I have noted in previous blogs, “How well do you sleep” is a question I ask of every new patient.
Medications to help you sleep do not improve the quality, just the duration. I would like to see a study that looked at the correlation between chronic use of sleep medications and Alzheimer’s disease. I have read studies that show a dramatic increase in the use of sleep medications as we age.
The Bottom Line:
Good quality sleep is essential to good health and may be a factor (or predictor) in Alzheimer’s disease. If you are not getting a good night’s sleep please seek nutritional advice. Sleep disorders are just one symptom of a larger health issue.
Source: June 1, 2015 National Institutes of Health