Bad Sleep Linked With Cognitive Decline

For older men, poor quality sleep could be taking a toll on the brain, according to a new study.

A team of researchers found an association between poor sleep quality -- in the form of fragmented sleep and poor sleep efficiency -- and cognitive decline in executive functioning among senior men. Executive functioning includes correcting for errors, troubleshooting and decision-making.

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.

Researchers found that certain aspects of poor sleep were associated with cognitive decline in the men in the study. Waking up after the onset of sleep, the number of long periods of time spent being awake at night, and lower sleep efficiency were associated with a 40 to 50 percent increased odds of clinically significant cognitive decline.

However, researchers did not find an association between duration of sleep and cognitive decline.

The team of researchers came from the California Pacific Medical Center Research Institute, 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 University of California, San Francisco, researchers showed a link between sleep-disordered breathing and dementia risk.