Split-night studies that don’t necessarily allow patients the time to change postures and a lack of reliable reimbursement can lead to position-dependent sleep apnea being missed.

Clinicians face several obstacles in identifying positional obstructive sleep apnea (POSA), which can hinder their ability to treat the condition.

Positional sleep apnea can affect as many as 49.5% of patients with mild sleep apnea and 19.4% of those with moderate sleep apnea. In people of Asian decent, these numbers are higher with as many as 75% of all obstructive sleep apnea patients having a positional component.1 “Many physicians working in sleep medicine really underappreciate the prevalence overall of positional sleep apnea,” says Samuel Krachman, DO, a pulmonologist and professor of thoracic medicine and surgery at Temple University’s Lewis Katz School of Medicine.

Positional sleep apnea refers to sleep-breathing difficulties associated with the supine position, which promotes a downward gravitational pull and causes the muscles in the airways to fall straight back. While there is currently a plethora of devices on the market to help people keep off their backs when asleep, identifying positional sleep apnea is not always easy.

In recent years, third-party payors have become stricter in their criteria for who qualifies for an in-lab sleep test. And those who are approved for in-lab studies are often only approved for a split-night study (instead of a two-night study, when a patient is diagnosed one night and then titrated the second night). During split-night studies, patients might not have time to assume all positions, says Krachman.

According to research, published in the journal CHEST, positional sleep apnea cannot usually be properly assessed during a split-night study.2

“The biggest issue, in many cases, is how we diagnose patients in the United States leaves a gap in knowledge,” explains Daniel Levendowski, president and co-founder of Advanced Brain Monitoring, which produces the FDA-approved Night Shift positional sleep apnea therapy device.

“[Sleep technologists] only need two hours of sleep time to know whether to move that patient to CPAP and in that two-hour window it is very difficult to get a good assessment on whether a patent has positional OSA. The end result is that many patients who are diagnosed with sleep apnea don’t know if they have positional sleep apnea,” says Levendowski.

While many sleep techs instruct patients to sleep on their backs during part of in-lab studies, there still might not be enough time during a split-night to make a determination whether a patient has positional sleep apnea.

It doesn’t help that patients are not accurate reporters of their own sleep position, so asking them about how they sleep may not yield any useful information. Even if patients go to sleep on their side, most everybody will shift during the night and sleep some time on their back, says David White, MD, chief medical officer at Philips. “Virtually everybody spends some time on their back, even if they don’t think they do,” he says.

Another reason why POSA may not be recognized is that clinicians are not always looking for it in sleep study reports. Most home sleep testing devices do capture sleep positions, but study interpreters may not consider that information to be relevant.

One reason may be because insurance companies do not usually reimburse for positional therapy devices. “The patients don’t really want to pay for it [out of pocket]. The doctors don’t really know how to get it for them easily, and so they don’t pursue it and just go with CPAP,” says White. “I think it is not so much a problem of recognition; it’s been more a problem of implementation.”

This is despite the fact that some wearable devices have been shown through clinical research to be just as effective as CPAP for people with POSA. One study, published in the Journal of Clinical Sleep Medicine, found that positional therapy is equivalent to CPAP at normalizing the AHI in patients with positional obstructive sleep apnea, with similar effects on sleep quality and nocturnal oxygenation.3

Specifically, the researchers looked at the Zzoma Positional Device, a device worn around the upper torso that keeps patients asleep on their sides by preventing supine sleep. They found that the device was successful in decreasing the AHI by more than 50%. Another notable finding is that there was minimal night-to-night variability in the non-supine AHI in patients with positional OSA, according to the study.

“If you get the patient off their back, they will normalize their apnea-hypopnea index to less than five, which is always our primary goal,” says Krachman, a coauthor.

It’s especially important to look at alternative therapies since many patients can’t tolerate CPAP. “If everyone was willing to use CPAP all the time, then it wouldn’t be an issue. Nobody would care, you’d just pop on the CPAP and everyone would be happy. The problem, obviously, is with CPAP adherence,” says White.

In the past, physicians once suggested that patients should tuck a tennis ball into their shirts to stay off their backs while they slept, but this method proved uncomfortable and many patients didn’t enjoy having a tennis ball in their beds. Technology has come a long way and now there are a number of devices that have been manufactured with patient compliance and comfort in mind.

NightBalance Lunoa, which was acquired by Royal Philips in 2018, slips inside a soft belt that can be worn around the chest during the night. When the person wearing the device rolls on their back, it gives off a gentle vibration, a sensation that the manufacturer says is just enough agitation to inspire a change of position, without disrupting sleep.

The Night Shift, which is strapped to the neck, is another option that vibrates. The vibrations start at a low intensity and then slowly increase to instigate movement, explains Advanced Brain Monitoring’s Levendowski.

Another positional sleep aid, the CPAPology Sleep Noodle Positional Sleep Aid, targets snoring. A foam cylinder, much like a pool noodle, is strapped around the abdomen, encouraging people to sleep on their sides. “We tried to find a foam that would be comfortable while still offering the right support to keep that patient off their back,” says Kevin Gowanlock, president of KEGO Corporation, the company that manufactures the device.

Research has already demonstrated that positional therapy is effective at reducing apneas, but physicians also might find that patients are more compliant with positional sleep apnea therapies than with their CPAP machines. One study, published in the journal SLEEP, found that people who used this method had compliance rates of up to 71%.4

Depending on the physician’s approach, positional therapy can be used as a primary treatment, in combination with CPAP or an oral appliance, or it can be tried after other therapies fail. “I myself would put them on the positional device first, rather than going to CPAP first,” says White.

“If someone gives you a device to wear around your chest that gets you off your back from time to time—it is much more tolerable to the vast majority of people and so it will end up getting a fair number of more people treated,” says White.

Lisa Spear is associate editor of Sleep Review.


1. Mo J, Lee CH, Rhee C, et al. Positional dependency in Asian patients with obstructive sleep apnea and its implication for hypertension. Arch Otolaryngol Head Neck Surg. 2011;137(8):786790.

2. Mador MJ, Kufel TJ, Magalang UJ, et al. Prevalence of positional sleep apnea in patients undergoing polysomnography. Chest. 2005;128(4):2130-7.

3. Permut I, Diaz-Abad M, Chatila W, et al. Comparison of positional therapy to CPAP in patients with positional obstructive sleep apnea. J Clin Sleep Med. 2010 Jun 15;6(3):238-43.

4. van Maanen JP, de Vries N. Long-term effectiveness and compliance of positional therapy with the sleep position trainer in the treatment of positional obstructive sleep apnea syndrome. Sleep. 2014 Jul 1;37(7):1209-15.