Bad Sleep Pattern Linked to Brain Damage, Increased Risk of Stroke for the Elderly: Study

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A new study has discovered that poor sleep quality, or what is called fragmented sleep, among the elderly is associated with damages in the brain that leads to an increased risk for stroke.

The study, published in the American Heart Association's journal Stroke, found that seniors who have frequently disturbed sleep, or sleep that is marked by constant awakenings or arousals, is associated with severe arteriosclerosis and more tissue in the brain that lacks oxygen. Both of these conditions lead to a heightened risk for stroke as well as cognitive impairment.

“The forms of brain injury that we observed are important because they may not only contribute to the risk of stroke but also to chronic progressive cognitive and motor impairment,” said lead investigator Andrew Lim, M.D., an assistant professor of neurology at the University of Toronto, Canada, in a press release.

While the association between sleep patterns and cardiovascular disease has been studied in the past, the researchers noted that this is the first study to look into the relationship between sleep disruption and both brain tissue and blood vessels on a microscopic level.

For the study, the researchers examined the autopsies of 315 people whose ages averaged at 90. These elderly had their sleep monitored around-the-clock for at least one whole week, checking for rest and activity. Both their sleep quality and circadian rhythm were quantified.

Overall, 61 percent of the elderly showed signs of moderate to severe brain blood vessel damage, and 29 percent of them suffered from a stroke.

The researchers found that, among those who have fragmented sleep patterns, those who had greater fragmentation were 27 more likely to have severe arteriosclerosis. They also found that for every two additional arousals per hour of sleep, there is a reported 30 percent increase in the odds of having visible signs of oxygen deprivation.

The researchers noted that these findings are independent of other cardiovascular risk factors, which include body mass, smoking history, diabetes and hypertension, as well as other medical conditions such as Alzheimer’s disease, pain, depression or heart failure.

“However, there are several ways to view these findings,” explained Lim, “sleep fragmentation may impair the circulation of blood to the brain, poor circulation of blood to the brain may cause sleep fragmentation, or both may be caused by another underlying risk factor.”

While the study findings suggested that monitoring sleep patterns might be used to identify seniors who are at risk for stroke, more research is needed to clarify several points whether brain blood vessel damage is a consequence or a cause of sleep fragmentation; the role of specific contributors to sleep fragmentation such as sleep apnea and the underlying biological mechanisms.