Scientists Found the Length of Sleep in the Elderly Affects Cognitive Function

Studies have shown that when the elderly sleep for less than 5.5 hours or more than 7.5 hours, their cognitive ability will decrease; proper sleep duration can help maintain the brain’s cognitive function.

Seattle, WA (Periodical News) – One of the most obvious symptoms of Alzheimer’s disease is memory and cognitive decline. The Washington University Sleep Medicine Center recently found that even if the effects of early Alzheimer’s disease are taken into account, sleep time older adults who are too short and too long will have reduced cognitive ability. This research has been published in the journal Brain.

A total of 100 participants in the study, with an average age of 75, strapped electroencephalograms (EEG) to their heads while sleeping to provide the research team with 4 1/2 years of monitoring. Participants also provided samples of cerebrospinal fluid to measure protein levels in Alzheimer’s disease. Studies have shown that participants who sleep less than 5.5 hours or more than 7.5 hours a night have lower cognitive scores, while those in the middle range have stable scores.

“It’s been challenging to determine how sleep and different stages of Alzheimer’s disease are related, but that’s what you need to know to start designing interventions,” said first author Brendan Lucey, MD, an associate professor of neurology and director of the Washington University Sleep Medicine Center. “Our study suggests that there is a middle range, or ‘sweet spot,’ for total sleep time where cognitive performance was stable over time. Short and long sleep times were associated with worse cognitive performance, perhaps due to insufficient sleep or poor sleep quality.”

“It was particularly interesting to see that not only those with short amounts of sleep but also those with long amounts of sleep had more cognitive decline,” “It suggests that sleep quality may be key, as opposed to simply total sleep.” said coauthor Dr. David Holtzman, scientific director of the Hope Center for Neurological Disorders at Washington University School of Medicine.

Although the study cannot prove whether sleep duration and sleep quality are related to the cause of Alzheimer’s disease, it shows the benefits of “appropriate sleep” in maintaining cognitive function. In particular, Alzheimer’s disease is the main cause of the cognitive decline in the elderly, and lack of sleep is a common symptom of Alzheimer’s disease and the driving force that accelerates the progression of the disease, so proper sleep duration is very important.

There is still no way to cure Alzheimer’s disease completely. Medical personnel can only provide supplementary treatment for the mental and cognitive symptoms produced at different stages of the disease. In the process of continuous development of the disease, people can only delay the course of the disease or slow down the symptoms as much as possible.

The most common early symptoms of Alzheimer’s disease are loss of short-term memory and cognitive function. Other symptoms may gradually appear as the disease progresses, including language disorders, disorientation, emotional instability, inability to take care of themselves, and various behavioral problems. Even though the course of the disease is different for each person, when the condition worsens, the patient will lose physical function and eventually die.

“Often, patients report that they’re not sleeping well. Often once their sleep issues are treated, they may have improvements in cognition. Physicians who are seeing patients with cognitive complaints should ask them about their quality of sleep. This is potentially a mod factor .” said co-senior author Beau M. Ances, MD, PhD, the Daniel J. Brennan, MD, Professor of Neurology.