Diagnose sleep apnoea from your own bed

T

housands of people have a dangerous health condition they don’t even know about. Sleep apnoea causes a person’s breathing to stop and start while they’re sleeping. It leaves patients feeling exhausted, moody and struggling to concentrate. And individuals with sleep apnoea often wake up with a nagging headache.

The symptoms may sound relatively minor, but sleep apnoea is linked with serious health problems such as high blood pressure, heart failure, strokes and type 2 diabetes. It also increases the chances of having a serious road accident caused by tiredness.

The illness can have a devastating effect on someone’s quality of life if it goes undiagnosed. But up to 80% of sleep apnoea patients are unaware of their condition.

Patients with suspected sleep apnoea are often referred to a sleep specialist who can diagnose the condition in hospital using polysomnography, a technique to monitor brain waves, eye movement and blood oxygen levels during slumber.

Technicians place small electrodes on the patient’s scalp, temples, chest and legs to record the data. Although accurate, it can feel uncomfortable and unfamiliar for the patient and they may struggle to drift off in the clinical setting.

Plus, during the Covid-19 pandemic, many sleep laboratories have stopped accepting patients, leaving many individuals with sleep apnoea without support.

Many experts agree that a less-invasive test to diagnose sleep apnoea would be valuable. That’s the thinking behind Belgium start-up Sunrise. Its flagship product is an £89 at-home sleep test that is completely wireless and doesn’t require the patient to spend a night in hospital to get the answers they need.

Sunrise is the brainchild of sleep specialist Jean-Benoit Martinot, It has received £4.80m investment funding, plus support from the National Heart and Lung Institute and Imperial College London.

Sunrise’s AI-powered sensor sits on the user’s chin during the night. Credit: Sunrise

“Traditionally, sleep tests consist of hospital beds and being tied to endless cables and electrodes,” says Sunrise CEO Laurent Martinot, who happens to be Jean-Benoit’s son.

“Other conventional tests used at home are often bulky and provide less information than a hospital. Ensuring the user has a comfortable experience increases the chance of a more restful sleep, therefore providing more reliable results.”

Sunrise works through an AI-powered sensor that weighs just 3g. It sits on the user’s chin during the night and remains there thanks to a simple adhesive layer. The user downloads the accompanying mobile app and places the Bluetooth-integrated device on their chin before they go to sleep. When they wake up, their results are ready for them to explore.

The only thing to bear in mind, says Martinot, is the device may not be accurate for users who have a thick beard. He recommends men shave their faces before undergoing the sleep test.

“The device gives clear, actionable results overnight and, if a sleep disorder is suspected, users can choose to be put directly in touch with a sleep physician to pose the diagnosis and discuss next steps, cutting down the journey to treatment from what could be months to just days,” he reveals.

Sunrise works by detecting micro-awakenings – short (3-15 seconds) unconscious events. Too many micro-awakenings during the night makes for poor sleep. It’s why you may still wake up feeling less than rested after a good eight hours of rest. Sleep apnoea makes these micro-awakenings occur far more frequently than normal as the body strives to correct the person’s breathing.

“Micro-awakening, when caused by an obstructive event, is a natural defence mechanism from the body,” says Martinot. “The micro-arousal causes a stiffening of the back of the throat, allowing the air to circulate again.”

The gold standard technique for measuring this respiratory effort involves looking for changes in pressure in the oesophagus called the intrathoracic pressure. Martinot says that the Sunrise device can detect micro-arousals based on the movement of the user’s chin overnight – a measure called mandibular movement.

It can also detect sleep bruxism (teeth grinding) and more minor sleep disorders, such as hypersomnia (sleeping too much) or insufficient sleep syndrome.

If the device suspects a condition like sleep apnoea, the user can connect remotely with a sleep physician to determine the best course of treatment. The healthcare professional may recommend a CPAP machine that gently pumps air into a mask worn during sleep.

There were several challenges that had to be overcome during the development phase of the device, reveals Martinot. The first step was to understand how to get useful information out of involuntary chin movements.

The team used traditional polysomnography to determine the connection between mandibular movement and poor sleep. The next step was to work out the best technology to measure these tiny movements in a device that would be both non-invasive and inexpensive.

“Another challenge was to develop the artificial intelligence algorithm allowing an automatic analysis with reliable, reproducible and immediate results,” he reveals. “It was made possible by training the algorithm to recognise characteristic patterns, just like the sleep specialist is doing when scoring manually.

The device has been validated in a clinical trial, described in the scientific journal JAMA. In the trial, 376 patients with suspected sleep apnoea were tested with either the Sunrise product or underwent traditional polysomnography tests in a sleep laboratory.

The investigation was led by French sleep specialist Jean-Louis Pépin from Grenoble Alps University. The researchers found that the Sunrise system provided an accurate estimation of respiratory disturbance during the night in patients with and without sleep apnoea compared to traditional polysomnography techniques.

“This approach may provide a suitable and convenient home-based alternative to the sleep centre setting and serve as a stand-alone tool for automated assessment of obstructive sleep apnoea,” concluded the authors.

Now the device has been validated, the company’s long-term ambition is to expand globally, beyond the French, Belgium and UK markets where Sunrise is currently active. The ultimate goal, says Martinot, is for Sunrise to become fully integrated into national healthcare systems so the device can help as many patients as possible.

Sunrise has recently received approval from the French National Authority of Health to reimburse and test out the effectiveness of the device on thousands of patients.

“Our priority for 2021 is to continue to build awareness of Sunrise in the UK - both amongst consumers and in the medical community – with the ambition of becoming fully integrated within the NHS pathway,” Martinot reveals. “Breaking into the US market in 2022 is also a top priority.”