Poor Sleep Linked to Cognitive Decline

poor sleep linked to cognitive decline

A study of older men released last week, found a link between poor sleep quality and the development of cognitive decline over three to four years.

A team of researchers found that high levels of fragmented sleep and lower sleep efficiency – but not sleep duration – in older men is associated with a 40-50 percent increase in cognitive decline in executive function. Executive function, according to study authors, includes the ability to plan and make decisions, the ability to troubleshoot and correct errors, as well as abstract thinking.

The study, published in the journal, Sleep, included 2,822 “cognitively intact” men with an average age of 76, who were followed for an average of 3.4 years. Sleep data was collected from each study participant via a wrist actigraph for an average of five nights, and the men also underwent cognitive functioning assessments.

This cognitive decline is equivalent to the effects of a 5-year increase in age, the researchers said.

“It was the quality of sleep that predicted future cognitive decline in this study, not the quantity,” according to Terri Blackwell, a statistician at the California Pacific Medical Center Research Institute. Other team researchers came from Harvard Medical School, University of California in San Francisco and San Diego, the University of Minnesota and several VA centers.

It should be noted that researchers did not find that poor sleep quality caused cognitive decline; it only showed an association. Other studies have also shown similar associations. Researchers from INSERM and Stanford University, for instance, showed that daytime sleepiness is linked with cognitive impairment among senior men and women. In another study from the University of California, San Francisco, researchers showed a link between sleep-disordered breathing and dementia risk.

“With the rate of cognitive impairment increasing and the high prevalence of sleep problems in the elderly, it is important to determine prospective associations with sleep and cognitive decline,” said Blackwell.