Alzheimer's disease Brain Sunnybrook Magazine – Fall 2016

Could sleep affect your Alzheimer’s disease risk?

Woman sleeping

A good night’s sleep does more than banish fatigue and get the mind and body ready for another day. It may also help lower the risk for dementia by utilizing the brain’s waste removal channels, called perivascular Virchow-Robin spaces.

Brain scientists at Sunnybrook looked at the brain scans and overnight sleep study results of 26 patients who had a stroke or transient ischemic attack (TIA), also commonly referred to as a mini-stroke. They found that these patients had enlarged perivascular spaces – which can be seen on 3-D MRI brains scans – suggesting blockage of these channels.

These findings are the first to show, in humans, a link between poor quality sleep and enlarged perivascular spaces – the fluid-filled channels that surround the brain’s blood vessels to drain toxins and waste products, especially during stages of deep sleep.

“We looked at the volume of perivascular spaces on their MRI scans and correlated them with markers of sleep fragmentation from their sleep studies,” says Courtney Berezuk, the study’s co-lead author and a neuroimaging analyst in the L.C. Campbell Cognitive Neurology Research Unit at Sunnybrook, directed by Dr. Sandra Black. “In those with poor-quality sleep, the enlarged perivascular space volumes were larger than those with healthy sleep patterns.”

Previous studies have shown a cause-and-effect relationship between fragmented sleep and a higher risk of cognitive diseases such as Alzheimer’s and dementia.

“Sunnybrook’s work with enlarged perivascular spaces are an extension of these studies,” says Dr. Mark Boulos, the study’s principal investigator and stroke and sleep neurologist in the Hurvitz Brain Sciences Program at Sunnybrook.

“These findings could be particularly important for patients suffering from stroke or dementias such as Alzheimer’s disease, which are thought to arise from the build-up of toxic amyloid protein in the brain, as sleep may be an important factor in their development,” says Dr. Boulos.

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Marjo Johne