Ask the doctors: Fitful sleep not necessarily a sign of Alzheimer’s disease

Dear Doctor: My husband has fallen into a strange sleep pattern. Some nights he’s awake until 3 a.m., tosses and turns all night, then wakes up tired. I’ve read that strange sleep cycles may be linked to Alzheimer’s disease, which his mother had. I’m worried, but what can I do?

Dear Reader: First, a bit of reassurance. More than half of older adults report having problems with sleep, including difficulty falling asleep, too much time spent in light sleep, waking up too often during the night and having trouble staying asleep. These can be the result of illness, anxiety, depression, life changes, a side effect of certain medications, too much electronic screen time or poor sleep habits.

It’s true that disrupted sleep is common among people who have been diagnosed with Alzheimer’s disease. They sleep less during the night, and the quality of that sleep is often poor. As a result, they spend their days feeling drowsy and will often take naps or sleep for hours at a time. Recent research suggests that the onset of fitful or fragmented sleep can also be an early indicator of Alzheimer’s disease, one that precedes the more well-known symptoms of memory problems and cognitive changes.

A study published last year in the journal JAMA Neurology found that people with no obvious cognitive issues, but whose sleep cycles had become altered, were more likely to have clumps of certain types of proteins in their brains. Known as amyloid plaques, these clumps collect between neurons and disrupt the cellular function in the brain.

Another study, published earlier this year in the journal Science Translational Medicine, also assessed sleep patterns in people with no memory or behavioral problems. The researchers found that a drop in the quantity of slow-wave sleep that someone got each night – that’s the deep sleep that leaves you feeling rested and refreshed – was associated with a buildup of a brain protein known as tau. Elevated levels of tau brain proteins, which form tangles in the brain and lead to atrophy, are commonly seen in people with Alzheimer’s disease.

Since your husband’s family has a history of Alzheimer’s disease, we suggest that you consider broaching the subject with your family doctor. There is no single test for Alzheimer’s disease at this time, but your doctor has access to a variety of diagnostic tools that can be helpful. This includes taking a detailed medical history, and using specially crafted verbal tests designed to assess cognitive function. If it appears to be necessary, your doctor may suggest a neurological exam that includes brain imaging. Taken together, these will establish a baseline for future comparison.

Cognitive issues aside, getting an adequate amount of high-quality sleep each night is important to many areas of health and well-being. We encourage your husband to discuss his changing sleep patterns with his doctor. It’s possible that they can uncover and address an underlying cause of the change.