By Sullivan, Michele G.
Clinical Psychiatry News , Vol. 40, No. 8
AT THE ALZHEIMER'S ASSOCIATION INTERNATIONAL CONFERENCE 2012
VANCOUVER, B.C.--Disordered sleep in mid-to late life is associated with an increased risk for future cognitive impairment and may alter the dynamics of the Alzheimer's disease--associated protein amyloid-beta, according to several studies.
It's important that physicians recognize disordered sleep as a modifiable risk factor, Dr. Kristine Yaffe said in an interview.
"Please attend to sleep hygiene in your elderly patients," said Dr. Yaffe, director of the memory disorders clinic at the San Francisco VA Medical Center. "Some people think that 50% of elderly people have some kind of sleep complaint. They are common and they are treatable."
Dr. Yaffe and her colleagues studied 1,309 elderly women who completed several days of sleep observation as part of a 15-year longitudinal study. They measured the motor activity of the women (mean age, 82 years) during sleep via wrist actigraphy. All of the participants had several neuropsychological evaluations and cognitive measurements during the study. A sub-set of 298 patients also underwent polysomnography.
After 5 years, women with sleep-disordered breathing were twice as likely to develop mild cognitive impairment or dementia as were those who slept normally. There was a similar risk level for women who had delayed sleep acrophase--difficulty falling asleep before the early morning hours and trouble waking up before late morning or early afternoon.
Women with greater nighttime wakefulness were more than twice as likely to show impaired global cognitive functioning, and twice as likely to have delayed verbal recall.
"We already know that sleep deprivation and abnormal sleep patterns are associated with falls and increased morbidity and mortality" said Dr. Yaffe, who also is a professor in the departments of psychiatry, neurology, epidemiology, and biostatistics at the University of California, San Francisco. "This is the first study showing that disordered sleep is a risk factor for later cognitive problems.
"It's important for clinicians to check for sleep problems and excessive daytime sleepiness as a possibly treatable cause of later cognitive problems," she said at the meeting. "Sleep habits are as important in prevention of dementia as diabetes and obesity. …