Researchers investigate the benefits of sleep on memory, mental health and overall quality of life

What role does sleep play in middle-aged and older adults’ memory function? That’s just one of the topics that researchers Thanh Dang-Vu and Melodee Mograss are investigating at Concordia's Sleep Lab.

“We know that when we age our cognition and memory change, and some people are more susceptible to develop problems of memory with age,” says Dang-Vu, a neurologist and associate professor in the Department of Health, Kinesiology and Applied Physiology.

“We think that sleep plays an important role in memory function, but what’s going to be investigated is to what extent sleep contributes to memory decline with aging.”

Dang-Vu, who is also the Concordia Research Chair in Sleep, Neuroimaging and Cognitive Health and a member of the Center for Studies in Behavioral Neurobiology and the PERFORM Centre, says he and his team are hoping to learn if there are specific sleep activity signatures that could help illuminate the connection between sleep and memory.

Mograss, a cognitive neuropsychologist who coordinates research activities at the Sleep Lab, is also investigating the benefits of sleep on cognitive functions. She is particularly interested in the combined effects of sleep and exercise on memory.

She is currently completing a study evaluating whether an acute physical exercise and a nap have synergistic benefits on memory functions in a group of young healthy participants.

And that is far from their only research projects. Dang-Vu is also investigating insomnia in middle-aged and older adults, in collaboration with Jean-Philippe Gouin, associate professor and Canada Research Chair in the Department of Psychology, as well as people who experience narcolepsy and hypersomnia — conditions where patients have difficulty staying awake during the day and are left feeling unrefreshed by the plentiful sleep they get.

“We’re trying to understand how sleep affects brain health and identify the brain mechanisms that take place when people have sleep problems,” Dang-Vu says.

The role of sleep in preventive health

It’s hard to understate the importance of the Sleep Lab research projects.

“We know that sleep is affecting not only people’s daily lives but also their ability to work, concentrate, socialize,” Dang-Vu says.

“Sleep has many implications not only in mental health but also physical health, and has links with diabetes, obesity, infections and immunity. This research is really speaking to the prevention of health problems.”

Over the past few years, Dang-Vu and Gouin have recruited participants with chronic insomnia to undergo sleep tests and cognitive behavioural therapy for insomnia (CBTI), in order to assess their responsiveness to the treatment.

In the recently published results, they’ve learned that a specific type of brain wave, which blocks external stimuli during sleep to protect the brain and is related to memory processing, is directly connected to how well patients respond to CBTI. People who have more of these brain waves, called sleep spindles, have been more receptive to the therapy.

“These studies will allow us to more precisely understand the types of insomnia and how they affect treatment,” Dang-Vu says.

The researchers just completed the second phase of the study, focusing on the connection between insomnia and memory; the third phase, underway now, will use brain imaging to understand the brain structures at play in insomniac patients.

‘The brain seems partially asleep while the person is awake’

In his study of narcoleptic and hypersomniac patients, Dang-Vu is hoping to understand the brain mechanisms that underpin those conditions and see what distinguishes them from each other using brain imaging.

The researchers recently published the first brain imaging study on idiopathic hypersomnia, reporting that when hypersomniac patients are awake, their brain activity shows patterns that resemble what normal sleepers experience when they are sleeping.

“The brain seems partially asleep while the person is awake,” Dang-Vu says. “This suggests that individuals with idiopathic hypersomnia might not be able to properly transition from deep sleep to being awake.”

The Sleep Lab’s insomnia and narcolepsy research projects are funded by Canadian Institutes of Health Research grants, and they have received funding for their study on sleep’s role in memory from the Natural Sciences and Engineering Research Council of Canada. The Fonds de recherche du Québec – Santé has also supported their work.

Find out more about Concordia’s PERFORM Centre.