The Woolcock Institute of Medical Research

New research is set to reveal why some people with the common snoring condition obstructive sleep apnea struggle with daytime brain fog while others escape unscathed.

Researchers at the Woolcock Institute of Medical Research in Sydney have long been puzzled why the common night-time breathing condition OSA affects people very differently.

“OSA is very common but its impact on individuals differs considerably,” says Dr Rick Wassing, a co-investigator on a new research project underway at the Woolcock. “While some people with the condition struggle through the day with sleepiness and fatigue, others appear to be virtually resistant to the negative side effects. With the results of this study we will be able to predict who is resistant and who is vulnerable.”

One in ten middle-aged Australians have OSA, a snoring disorder that disrupts breathing, limits blood oxygen levels and interferes with sound sleep. The problem is growing as more people work irregular hours, particularly overnight, in an increasingly globalised economy. When OSA goes untreated, the brain can be subjected to repeated periods of hypoxia, or dips in oxygen levels, that occur with the pauses in breathing during sleep. As a result, the disorder is strongly linked to cognitive problems, as well as workplace and vehicle accidents.

Specialists use the severity of a patient’s condition as a guide for how likely they are to suffer from cognitive function issues, but this is not always an accurate indicator. The Woolcock team is seeking to find a more reliable marker of OSA fatigue vulnerability which could be used by clinicians to help identify and treat at-risk patients. 

They are enlisting 100 people with OSA, or suspected OSA, to undergo a one-week sleep assessment at home using a sleep diary and a wrist device that monitors movement. Volunteers also spend two nights in the Woolcock’s Glebe sleep laboratory to assess the effects of extended wakefulness on cognitive performance. 

“We’ll get volunteers on our driving simulator when they’re under-slept and see how the lack of sleep affects each person’s driving ability,” explains Dr Wassing. “By looking at brain activity, saliva and blood, we’ll collect clues to tell us what those most susceptible to fatigue and sleepiness have in common, and more importantly how they differ from those who are resilient.”

The team hope to find markers that can definitively tell whether a single OSA patient falls within the susceptible or resistant group. “With this vital information they can then go on to get the right clinical care to prevent difficult side effects, like car accidents, low productivity and  low mood,” Dr Wassing says. “Ultimately, we aim to help people with OSA live their lives without the frustrating performance side effects.”