The science of snoring

Sleep apnea affects one-in-five adults in Canada, often disrupting sleep and contributing to risk factor for conditions like heart disease and accident rates worldwide. Yet, the experience of sleep apnea remains mysterious for many -- an unexplained feeling of fatigue or being told by a family member that they snore.

Dr. Walid Ashraf, a recent UM PhD graduate, is working to pinpoint the elusive causes of sleep apnea in the lab of Dr. Zahra Moussavi at the Price Faculty of Engineering. Ashraf recently published his design for a new test using sound to map a patient’s airways, an important step toward faster and more effective diagnostic tools testing for everyone.

“It is very difficult to determine the exact cause of apnea, of which there are many, but in our study we’ve determined that the sound of your voice holds clues to the shape of your airway and can help us pinpoint the exact location of the problem,” says Ashraf.

Their patented design uses a contact microphone on the neck, over the throat, and a small speaker in the mouth, producing consistent results in pilot studies and laying the groundwork for the next phase of standardized tests.
 

A new answer for apnea

For some, apnea may be related to diet or a heavy tongue that blocks the airway while they sleep, but for many the cause is a hidden abnormality in the shape of the airway. Current sleep apnea testing in Manitoba depends on just one sleep clinic at Misericordia Hospital in downtown Winnipeg, which often has a waitlist stretching more than a year. 

Once a patient waits their turn, they spend the night at the clinic with their sleep monitored using electrodes on their head. Patients who frequently snore are often told to use a CPAP machine, an assisted breathing machine worn during sleep, while others opt for the more permanent solution of surgery.

“The results of the sleep clinic, determining whether you have obstructive, neurological, or both forms of the disorder, but we’re not able to identify the cause of the disorder with this method, and due to the difficulty of precise diagnosis, current surgical options have only a 50% rate of success,” says Dr. Moussavi. “So far, using only sound analysis during 5-minute breathing tests while the patient is awake, we have screened for apnea with 86% accuracy, comparable with current home monitoring devices.”

The project is currently in the research stage and for full validation of the results they need CT scans of the upper airway for a number of participants. Once they collect enough data, Moussavi and Ashraf will bring a new device to market that will cut wait times from a year to a four-minute test and can be administered by any nurse or family physician, like getting an x-ray at the dentist.

Mousavi and Ashraf have already started to apply their test on people thought to have sleep apnea and an age-matched healthy control group. They are now seeking research participants to complete the study and move to the next steps for a market ready product. 

To join the study one may send an email to Zahra.Moussavi@umanitoba.ca.
 

The symptoms of sleeplessness

“Even when you are awake, aspects of an obstructive sleep apnea could be affecting your upper airway, so it is possible to detect it even when awake,” says Ashraf.  “With the number of people today here in Manitoba and around the world being tested and diagnosed, I think it’s more important than ever to have a consistent and cost-effective test. That’s what motivates my research.”

A healthy sleep cycle regulates all the systems of our bodies. From heart health to digestion, if sleep is regularly interrupted by apnea it can negatively impact every aspect of life and is also associated with anxiety, depression, memory loss and even dementia.

“The beauty of Walid’s approach is that it provides more precise information about the cause of the apnea in a fraction of the time and resources of current tests, and that will lead to more precise courses of treatment in the future,” says Moussavi. “For those living with obstructive sleep apnea, a precise diagnosis will be life changing.”