Multi-night home sleep testing: Why is it important in the diagnosis of sleep apnea?

Traditionally the pathway to apnea diagnosis has looked like this: a doctor will refer the patient to a sleep center where an in-clinic polysomnography will be performed. An overnight stay for the patient, a night’s worth of data collected for the sleep specialist.
Polysomnography (PSG) has, for good reason, been considered the gold standard in not only the detection of sleep apnea but other major sleep disorders. In terms of accuracy and variety of data collected, it has been top of the class for decades.
But that isn’t to say that it's without its shortcomings- can one night in unfamiliar settings with compromised comfort provide a true idea of how a patient’s sleep?

So then we come to the explosion of at-home sleep tests that have appeared on the market in recent years, no doubt accelerated in part by the COVID-19 pandemic. They undoubtedly cut down wait-lists for in-clinic sleep studies, offer better patient comfort, and the possibility of multi-night sleep data. But they also create a panoply of new issues: misdiagnosis and misdetection, remote patient monitoring, data protection and so on…

It goes without saying that the issue is far from clean-cut. In this article, we’ll take a look at the pros and cons of multi-night home sleep testing, where it’s outperforming traditional in-clinic sleep studies and where it’s still missing the mark.

Multi-night home sleep testing: The advantages

Due to factors such as cost, availability of equipment, and other logistical constraints, a single night sleep study is the standard when it comes to the detection of sleep apnea. But studies have shown that the ‘one night only’ approach can lead to misdiagnosis. A 2017 study saw that single-night sleep studies could miss moderate obstructive sleep apnea (OSA) in 60% of cases and mild OSA in 84% of cases. Why? Because depending on the severity of a patient’s apnea, variability from night to night can be significant, with important factors such as oxygen desaturation and severity shifting between nights.

Furthermore, a study carried out 10,340 subjects showed how patients suffering from mild to moderate forms of OSA slip under the radar of single night sleep studies, meaning that milder cases are often missed, and severity is often misdiagnosed. Accurate diagnosis relies on the patient really sleeping, that is to say, a sleep comprised of multiple sleep stages (both REM and non-REM sleep). Perhaps a tall order for a patient undergoing a single-night sleep study, spending the night in inhabitual circumstances (wearing the equipment, perhaps in-clinic…).

Multi-night home sleep testing seems a viable, accessible alternative. Offering the patient more convenience and comfort, and the healthcare professional a better representation of the patient’s sleep, and a way to counterattack the problems posed by night-to-night variability that arise in single-night sleep studies. Problems like, the ‘first-night’ effect which studies have shown leads to decreased sleep time, lower sleep efficiency and lesser REM sleep linked to the changes in environment (and the adaptation to equipment). But also the night-to-night variability of sleep apnea itself, particularly, obstructive sleep apnea, which can be due to various causes that include the consumption of alcohol and certain medications, sleep position and even some studies suggest changes in evening leg fluid volume and overnight rostral fluid shift.

The case for multi-night home sleep testing is strong. So what then, if any, are the disadvantages of multi-night at-home sleep testing?

Multi-night at-home sleep testing: The disadvantages

As we have already seen, multi-night at home sleep tests (HSTs) hit the mark when it comes to several blocking points presented by single night sleep tests and PSG based studies. But that isn’t to say that they are the perfect solution. Let’s take a closer look at some of the complications and pitfalls of the HST from both the patient and provider perspective.

First, it is important to qualify the term HST or at-home sleep test. Typically, these devices are portable monitors that key metrics such as respiratory activity, breathing patterns and chest movement through the night (or across several nights). Other metrics can include blood oxygen levels, heart rate, movement and position changes and snoring events and intensity.
These metrics can help to diagnose sleep apnea but they are not immune to false negatives or other complications that can arise from things like common drugs, mouth-breathing, respiratorial co-morbidities and even the wearing of nail polish.

It is also important to note that most HST do not measure sleep quality or stages. In this sense, the HST remains a convenient and accessible first port of call for patients suspected of suffering from sleep apnea but is rather rudimentary in terms of diagnostic scope.

Another blocking point for the HST is the human factor, at-home sleep tests often mean that the patient is responsible for correctly installing the device themselves and keeping it correctly installed throughout the night. As the sleep technician is off-site, this can lead to lower signal quality and data that is unreliable.

Not to mention, comfort, while we are light years away from the discomfort of the in-clinic PSG, it is still important to take in consideration, when certain at-home sleep tests, require the patient to wear masks, wires and so on.

The HST can make the sleep technician’s job trickier and the role of remote patient monitoring ever more important. Beyond managing the correct use of the device, ensuring un-disrupted signal quality (often via Bluetooth), this means managing and analyzing multi-night data, storing and protecting said data in a responsible manner and so on.

Multi-night at-home sleep testing: What if there was a better way?

As we can see, it is undeniable that multi-night at-home sleep testing has simplified and democratized access to sleep apnea diagnosis for thousands of people. It provides a comfortable, cost-effective, convenient alternative for patients and access to multi-night data for providers. However, the bio-signals currently monitored have been around for decades and far from inclusive and several technical complications mean that false negatives or unusable night data is common.
Not to mention that the remote patient monitoring infrastructure required by the provider is a complex affair.
It would be fair to say that all in all, there is still a long way to go.

Sunrise is an FDA-cleared at-home sleep apnea detection tool that uses mandibular movement as its key bio signal alongside more traditional signals such as airflow and oximetry. The device uses AI to aid in the detection of OSA as well as several other sleep related breathing disorders.

A relatively novel way to measure sleep, the movement of the mandibular jaw is clinically-proven as an accurate way to detect OSA. And can even detect sleep stages. As a bio signal, it is more inclusive and reliable than those used by traditional at-home sleep tests.

So how does it work in practical terms? The coin-sized device sits on the patient’s chin and measures mandibular movement across several nights. Before the night begins, the patient completes a short questionnaire about their sleep in-app, before being guided through the correct installation of the device. One single point of contact, means a lightweight, comfortable wearing experience.

Data is collected through the app, analyzed algorithmically and then made available on an online portal for healthcare providers, making remote patient monitoring, data collection and protection simpler.