Middle-aged adults who report symptoms of insomnia and are sleeping less than six hours a night may be at increased risk of cognitive impairment, according to a study by Penn State College of Medicine researchers. The results may help health care professionals understand which patients who report insomnia are at increased risk for developing dementia.

Insomnia is characterized by reports of difficulty falling asleep, difficulty staying asleep or waking up too early and not being able to get back to sleep. When these symptoms occur at least 3 nights a week and for at least 3 months, it is considered a chronic disorder. Researchers found that adults who reported insomnia and obtained less than six hours of measured sleep in the laboratory were two times more likely to have cognitive impairment than people with the same insomnia complaints who got six or more hours of sleep in the lab. The study results were published in the journal SLEEP on September 24.