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 "People discount the importance of sleep. So many
things seem so much more important than a few extra hours of sleep a
night," lead author Linda L. Chao told Reuters Health.
"The study suggests we shouldn't discount sleep importance," she
said.
Chao, from the University of California, San Francisco, collaborated
with researchers at the Department of Veterans Affairs Medical
Center in San Francisco on the study published in the journal Sleep.
Previous research has linked sleep disturbances to structural brain
changes, the authors note. In their study, sleep was associated with
the amount of gray matter in the brain's frontal lobe in particular.
"There's other corroborating data showing that insomnia and a
variety of psychiatric illnesses are reflected in reduced volumes in
the brain, which makes sense because sleep and mood are functions of
the brain," Dr. John Winkelman told Reuters Health.
A psychiatrist, Winkelman is chief of the sleep disorders clinical
research program at Massachusetts General Hospital in Boston. He was
not involved in the current study.
He described the frontal lobes as "an essential part of human
functioning," necessary for planning, strategizing, mood and affect.
Veterans with post-traumatic stress disorder (PTSD) frequently
complain about sleep difficulties, according to Chao and her
colleagues. Studies have found high rates of sleep disorders among
veterans of America's wars in Iraq and Afghanistan who had head
injuries or PTSD (see Reuters Health story of Oct. 28, 2011, here:
http://reut.rs/1g0AXW7).
For the current study, the researchers scanned the brains of 144
mostly male veterans using magnetic resonance imaging (MRI).
They measured sleep quality with the Pittsburgh Sleep Quality Index,
a crude, self-rated index that asks broad questions about sleep
patterns over the past month.
For example, the index asks participants a single question about the
time they usually went to bed over the past month and another about
how long it usually took them to fall asleep.
The researchers found participants who reported poor quality sleep
overall had less frontal lobe gray matter than vets who reported
sleeping relatively well.
In addition to sleep troubles, a host of psychological problems
plagued the study veterans. Half had abused alcohol, 40 percent had
had major depressive disorder at some point and 18 percent had PTSD.
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Still, the link between sleep troubles and brain volume held even
after the researchers took those problems and psychotropic medicine
use into account.
Winkelman cautioned against inferring a cause-and-effect
relationship between sleep and brain volume or generalizing the
results of a study on veterans with a range of psychiatric problems
to the general population.
But Chao believes the findings could apply to anyone, not just war
veterans.
Although she stressed that the study underscores the importance of a
good night's sleep, she agreed that it's not possible to say that
troubled sleep causes a decrease in frontal lobe gray matter, or
vice versa.
"We only know there's a relationship," Michael Breus, an Arizona
clinical psychologist who is board-certified in sleep disorders,
told Reuters Health. "We don't know which came first."
Breus was not involved in the current study. He applauded the
researchers for examining sleep patterns in war veterans, a group
particularly plagued with disturbed sleep.
"If they've been in an active theater of war, they haven't slept
well since they've been in an active war," he said.
He said polysomnography, which monitors people's sleep and collects
objective data, would have made the results of the current study
more meaningful.
Chao also said she would have preferred to use objective sleep data.
But the current report was based on a second look at data from a
prior study.
"The data says to us this could be a very interesting population to
learn more about," Breus said. "If we can learn more about veteran
sleep, we can help them sleep more." ___
Source: http://bit.ly/1hHYFq8
Sleep,
March 2014.
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