Brain scientists at a Canadian university are aiming to get a better handle on how sleep affects memory, problem solving and other cognitive functions in what they are billing as the largest such study ever to be done.

The researchers at Western University, based in London, Ont., are hoping to recruit upwards of 100,000 participants from around the world for the online study.

There's a lot about sleep and sleep deprivation and its effects on the brain that we just don't know. - Bobby Stojanoski , Western University

"There's a lot about sleep and sleep deprivation and its effects on the brain that we just don't know," Bobby Stojanoski, one of the research scientists, said in an interview. "For instance, how much sleep is necessary? Is that true for everybody? Are there certain sub-populations who require more or less sleep?"

A suite of 12 online tests will be used to assess how changes in sleep patterns affect performance. To take part, users register online at worldslargestsleepstudy.com then, over a three-day period, do the brain-function tests and fill in a questionnaire regarding sleep.

Volunteer participants will get a report on how they fared, and how they stacked up against others who've done the same testing.

'World's largest sleep study'

"We all have a bad night of sleep every once in a while, and we drive our cars and we go to work, but are we doing this in a cognitively deprived state?" Stojanoski said. "We hope to answer these questions."

The online tests, which can done on any computer, tablet or smartphone, are designed to assess different kinds of thinking. They involve challenges such as finding odd-one-out shapes, moving numbers into place and grammatical tests.

Some preliminary participants have already taken the tests and were given brain scans when fully rested and after a sleepless night, something that would not be practical on a wider scale. The online study — which about 15,000 people had signed up to take part in as of Tuesday morning — aims to extract equivalent information on a much larger scale.

While there's no end date to the study, the researchers hope to have gathered enough information to start their analysis and begin reporting findings by the end of the year.

Led by neuroscientist Adrian Owen at the university's Brain and Mind Institute, the handful of researchers hope that recruiting huge numbers of participants of various ages and all walks of life will lend a statistical reliability to the data collected.

"Our goal is to be the world's largest sleep study ever conducted," Stojanoski said. "With more people, we can more

accurately assess how fluctuations in your sleep affect cognition."

What we learn ultimately has the potential to change how millions of people go about their daily lives. - Adrian Owen, Brain and Mind Institute, Western University

While other sleep studies have claimed to be the "largest," the Western researchers say none has been subject to the scientific rigour of this study or examined links between cognition and sleep.

Owen, of Toronto-based Cambridge Brain Sciences, which designed the tests, has garnered attention for his brain research. His work includes showing that some apparently unresponsive brain-injured patients can actually be aware of their condition and can communicate.

"We have the opportunity in this study to learn far more about the brain's response to sleep than we have ever had before," Owen said in a statement. "What we learn ultimately has the potential to change how millions of people go about their daily lives."