Diagnosing obstructive sleep apnea at home

Obstructive sleep apnea affects millions of adults worldwide, including more than 24 million in the United States. However, most cases, 90%, remain undiagnosed.

The condition results from the upper airways becoming blocked while a person sleeps, which can reduce or stop airflow. As a result, people with obstructed airways can wake up multiple times throughout the night, feel tired throughout the day, and have headaches. They can also face increased risks for developing high blood pressure or having a heart attack or stroke.

“It’s a silent health crisis,” said Ha Uk Chung, Ph.D., vice president of research and development and a cofounder of Sibel Health, Inc. “Most people don’t know they have it.”

Creating a diagnostic tool for obstructive sleep apnea

In 2020, with support from an NHLBI grant, researchers at Sibel Health Inc. worked to augment their existing technology to help diagnose obstructive sleep apnea at home. The wearable system they designed is called ANNE^® Sleep.

The now FDA-cleared device was created to help doctors diagnose patients suspected to have moderate to severe cases of obstructive sleep apnea, but it can also be used in clinical research studies.

The concept for the system followed designs from prior FDA-cleared devices the company created for tracking a person’s cardiorespiratory metrics, including their heart rate, respiratory rate, body temperature, and oxygen saturation levels for premature babies.

Chung explains they had a specific vision in mind. Since at-home tests for sleep apnea can include multiple wires, chest bands, and breathing tubes, which can be cumbersome, they wanted to create a flexible, wearable sleep system. They wanted something that could easily attach to a person’s skin, collect a wide range of data, be easy to use, not interfere with their natural sleep, be used for multiple nights if necessary, and be cost-effective.

ANNE^® Sleep, the wearable device, uses two wireless sensors to track a person’s sleep patterns. One attaches to the skin of their chest. The other clips onto their index finger. A person wears both sensors before they go to sleep. As they sleep, the sensors measure their total sleep time through an artificial intelligence algorithm. It also measures their heart rate, snoring, body position, and blood oxygen saturation, among other factors.

After a person wakes up, they charge the sensors, which upload data about their sleep into a secure hub. A qualified physician could then assess their sleep patterns based on one or multiple nights of sleep.

If a person has at least five breathing interruptions during an hour of sleep due to fully- or partially-blocked airways, they have mild obstructive sleep apnea. Moderate forms occur when the airways are blocked at least 15 times. Severe forms start at 30.

Adults need at least seven hours of sleep each night to support their body’s many functions. If they constantly wake up throughout the night due to interrupted breathing, that sleep deficit can significantly impact their health, explained Shilpy Dixit, Ph.D., program director for prevention and sleep health, located within the National Center on Sleep Disorders Research, at NHLBI.

“The earlier an individual can be screened, diagnosed, and treated for obstructive sleep apnea, the better,” she said.

Treating obstructive sleep apnea varies, but may include mouthguards or devices, such as continuous positive airway pressure machines, to keep the airways open.

Testing the device against gold-standard methods

To see if the wearable sleep system could accurately diagnose obstructive sleep apnea, researchers started a clinical research trial with 225 adults suspected to have moderate to severe forms. They wanted to see how close the device came to polysomnography (PSG), the gold-standard for diagnosing obstructive sleep apnea.

PSG, an overnight sleep assessment, is only conducted at laboratories or accredited sleep centers. Its electric sensors attach to a person’s chest, eyelids, head, and chin to let researchers observe their breathing, heart rate, body movements, brain waves, blood oxygen levels, and sleep duration.

For the ANNE^® Sleep trial, participants completed an overnight sleep assessment at one of four sites in Illinois. During the visit, each participant’s sleep was assessed by PSG while they wore the ANNE^® Sleep sensors.

Both PSG and ANNE^® Sleep identified about one-third of adults with moderate to severe forms of obstructive sleep apnea. The results showed the wearable device could identify most moderate to severe sleep apnea cases with a low number of false positives compared to PSG.

After the trial, participants completed a post-study survey. Most users reported the system was easy to use, comfortable, and could see themselves using it again.

“User feedback is what motivates us,” said Chung. He explained that thinking about how patients are using the system to support their health drives the researchers to scale the technology.

Looking to the future

After ANNE^® Sleep received FDA clearance in July 2022, the researchers launched the product with select commercial partners. They are planning to expand their reach within the next year.

The system is suitable for all adults, but Chung envisions it may especially appeal to those with increased risks for obstructive sleep apnea who prefer to conduct overnight sleep assessments from the comfort of their home. This might include adults ages 65 and older or individuals who are pregnant.

“With obstructive sleep apnea being a significant issue among older adults and for so many people in our population, it’s encouraging to see new devices for diagnosing and treating sleep apnea,” said Stephanie M. Davis, Ph.D., a small business program coordinator within the Division of Extramural Research Activities at NHLBI. “It’s a great way to bring in new technologies that focus on an important unmet clinical need.”

To learn about obstructive sleep apnea, visit https://www.nhlbi.nih.gov/health/sleep-apnea.

To learn about the NIH Small business Education and Entrepreneurial Development (SEED) program, visit https://seed.nih.gov.