Could Sleep Problems Cause Brain Atrophy?
While previous studies have linked several factors to brain health, including physical activity, cholesterol levels, and blood pressure, new research suggests sleep quality could be another important factor to consider.
A new study in Neurology suggests that poor sleep quality may be associated with reduced volume and faster rates of atrophy in certain areas of the brain.
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“It is not yet clear if poor sleep quality is a cause or an effect of changes in brain structure, or if the relationship is bi-directional,” says lead study author Claire E. Sexton, DPhil, with the University of Oxford in the United Kingdom. “We found that the link between sleep problems and decline in brain volumes was particularly strong in adults over the age of 60 years.”
Sexton and colleagues examined the relationship between sleep difficulties—such as trouble falling asleep or staying asleep at night—and brain volume in 147 adults ages 20 to 84. They took two MRI scans of the participants’ brains, an average of 3.5 years apart, and asked them to complete a questionnaire about their sleep habits, including how long they slept, how long it took them to fall asleep, and whether they used sleep medications.
After analyzing these data, the researchers found that poor sleep quality was associated with reduced volume in the right superior frontal cortex and with an increased rate of atrophy in the frontal, temporal, and parietal regions of the brain. However, sleep quality wasn’t associated with declines in hippocampal volume or atrophy in that region of the brain.
The study authors say more research is needed to understand the nature of this relationship.
“On one hand, it has been proposed that sleep is ‘the brain’s housekeeper,’ serving to restore and repair the brain. It follows that if sleep is disrupted, then processes that help restore and repair the brain are interrupted and may be less effective, leading to greater rates of decline in brain volume,” Sexton says. “On the other hand, it may be that greater rates of decline in brain volumes make it more difficult for a person to get a good night’s sleep.”
Although their primary measure was overall sleep quality, the researchers also examined sleep latency (the amount of time taken to get to sleep at night), sleep efficiency (the proportion of time in bed spent asleep), and sleep duration.
“We found the closest links between decline in brain volumes and sleep efficiency, although a recent study from the National University of Singapore reported a relationship between rates of brain shrinkage and sleep duration,” Sexton says.
She and her colleagues say more research is needed to establish if it is the quantity or quality of sleep that is important.
“In the future, we’d also like to examine if improving sleep quality can help slow rates of decline in brain volume,” she says. “If so, improving people’s sleep habits could be an important way to promote brain health.”
—Colleen Mullarkey
Reference
Sexton CE, Storsve AB, Walhovd KB, Johansen-Berg H, Fjell AM. Poor sleep quality is associated with increased cortical atrophy in community-dwelling adults. Neurology. 3 September 2014. [Epub head of print].