Evidence is building that poor
sleep patterns may do more than make you
cranky: The amount and quality of shuteye you
get could be linked to mental deterioration and
Alzheimer's disease, four new studies suggest. Too little or too much sleep was equated with two
years' brain aging in one study. A separate study
concluded that people with sleep apnea --
disrupted breathing during sleep -- were more
than twice as likely to develop mild thinking
problems or dementia compared to problem-free sleepers. Yet another suggests excessive daytime
sleepiness may predict diminished memory and
thinking skills, known as cognitive decline, in older
people. "Whether sleep changes, such as sleep apnea or
disturbances, are signs of a decline to come or the
cause of decline is something we don't know, but
these four studies . . . shed further light that this is
an area we need to look into more," said Heather
Snyder, senior associate director of medical and scientific relations for the Alzheimer's Association in
Chicago, who was not involved in the studies. The studies are scheduled for presentation Monday
at the Alzheimer's Association annual meeting in
Vancouver. The largest of the studies, which examined data on
more than 15,000 women in the U.S. Nurses' Health
Study, suggested that those who slept five hours a
day or less, or nine hours a day or more, had lower
average mental functioning than participants who
slept seven hours per day. Too much or too little sleep was cognitively equivalent to aging by two
years, according to the research, which followed
the women over 14 years beginning in middle age. The study also observed that women whose sleep
duration changed by two hours or more a day from
mid- to later life had worse brain function than
participants with no change in sleep duration -- a
finding that held true regardless of how long they
usually slept at the beginning of the study. "We went in with the hypothesis that extreme
changes in sleep duration might be worse for
cognitive function because they disrupt the
circadian rhythm, so these results line up nicely,"
said study author Elizabeth Devore, an associate
epidemiologist at Brigham and Women's Hospital in Boston. "I think this gives us data to think about
sleep- and circadian-based interventions being a
route to address cognitive function." Circadian
rhythm is the term for the physical, mental and
behavioral changes that follow a 24-hour cycle. The other new research that associates sleep
and brain function follows: - Scientists from University of California, San
Francisco measured the sleep quality of more than
1,300 women over age 75 using sensor units and
recordings of physical changes during sleep. They
found that participants with sleep-disordered
breathing or sleep apnea had more than twice the odds of
developing mild cognitive impairment or dementia
over five years than those without those
conditions. Those with greater nighttime
wakefulness were more likely to score worse on
tests of verbal fluency and global cognition. - In France, nearly 5,000 mentally healthy French
people over age 65 were evaluated four times over
eight years. Researchers looked at different aspects
of insomnia and found that excessive daytime
sleepiness -- which was reported by 18 percent of
participants -- increased the risk of mental decline. Difficulty in staying asleep did not. - Scientists from Washington University School of
Medicine in St. Louis obtained samples of blood and
cerebrospinal fluid from three groups of volunteers
-- those with dementia, a healthy age-matched set
and a younger set -- over 36 hours and found that
daily sleep patterns were linked to levels of amyloid proteins. These proteins are recognized as an
indicator of Alzheimer's disease. While Snyder and Devore agreed that much more
research is needed, the studies potentially pave the
way for sleep interventions that could stave off
mental deterioration. "We may be able to help those individuals," Snyder
said. "If you're having problems with sleep, you
may want to follow up with your health care
provider." Because research presented at scientific
conferences has not been peer-reviewed and
published in a medical journal, results are
considered preliminary. Also, if you suffer from insomnia, don't worry that
you're doomed to develop dementia. Although the
studies report an association between sleep
disturbances and mental decline, they do not show
a cause-and-effect relationship. Source 1 Like |
