When a person has obstructive sleep apnea (OSA) their airway collapses multiple times during each hour of sleep, causing them to briefly stop breathing. As a result of these lapses in breathing, they are likely to experience snoring, daytime sleepiness, morning headaches, and trouble focusing. Obstructive sleep apnea also comes with an increased risk of other health problems, like stroke and heart attack. Experts estimate that in the U.S., up to 93% of women and 82% of men who have OSA remain undiagnosed.
Two types of studies can potentially detect obstructive sleep apnea. The first is an overnight sleep study in a lab or hospital, called polysomnography. The second is a home sleep apnea test. Although a home sleep apnea test does not measure brain waves during sleep, it does measure other factors that can help medical professionals determine if a person has OSA.
Home sleep apnea testing offers several advantages over in-lab polysomnography.
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What Is an At-Home Sleep Study?
A home sleep apnea test (HSAT) is an overnight test conducted outside of a hospital or sleep lab. HSAT can also be referred to as a home sleep test (HST), an out-of-center sleep test (OCST), out-of-center (OOC) recording, or polygraph (PG). This type of testing can accurately diagnose obstructive sleep apnea in some, but not all, people. Often, home sleep apnea testing costs less and is viewed as more convenient than an in-lab sleep study, because it takes place in the comfort of a person’s home.
When undergoing a home sleep apnea test, you generally have to pick up special equipment from your doctor’s office or a sleep clinic. Then, you carefully follow the instructions provided regarding how to use the various test devices given to you. You sleep as you usually would, except with specific devices connected to your body to collect data, for at least one night.
After the test is completed, the equipment must usually be returned, although some newer tests are disposable. A sleep specialist will analyze the data to see if you meet the criteria for obstructive sleep apnea.
Home Sleep Test Devices
Sleep tests are categorized according to how much and what type of data they collect. Type 1 and 2 tests collect more detailed data. For example, in-lab polysomnography performed with a technician is classed as a type 1 sleep test. Home sleep apnea tests are generally type 3 or 4 tests, which collect less data. The number of devices used in your home sleep apnea test depends on if your medical provider orders a type 3 or type 4 study.
Your home sleep apnea test devices may include:
- Breathing Sensor: Nasal cannula or nasal prongs are tubes that are placed in the nostrils and wrapped behind the ears. They analyze breathing patterns by tracking the air pressure when inhaling and exhaling. Sometimes, an oronasal thermistor, or a temperature sensor that sits between the nose and the mouth, is used to estimate airflow instead. A thermistor might be necessary for people who do not breathe through their noses as they sleep.
- Effort Belt: A belt may be wrapped around the chest or abdomen in order to measure movements associated with breathing. Data from this device can help differentiate between obstructive sleep apnea, where the person is making an effort to breathe, versus central sleep apnea, where the brain does not send the signal to inhale and exhale and therefore there is no movement. The effort belt often also secures the box storing the data collected from all sensors.
- Pulse Oximeter: A pulse oximeter is a device usually placed over a fingertip to measure how much oxygen is in the blood. Sometimes, a pulse oximeter is connected to an earlobe instead of a finger.
- Microphone: Generally, the nasal breathing sensor estimates snoring. However, sometimes an actual microphone is used to measure snoring. A sound sensor attached to the neck may also record sound and pressure.
- Data Collection Device: Usually, all of the sensors connect, either via wires or flexible tubes, to the data collection device. This device may feature buttons you are instructed to push when you want data collection to begin and end, as well as status lights indicating the device is powered on and recording.
Less commonly, certain specialty devices may be used to measure other parameters related to sleep apnea. These are often used in conjunction with the standard devices:
- Apnea Risk Evaluation System (ARES): The ARES system of home sleep apnea testing involves monitoring many of the same measures, but saving the data to a device worn on a headband that also measures head position and movement.
- WatchPAT: The WatchPAT is a device worn around the wrist, similar to a watch, with a monitor that goes on a finger. The finger monitor measures peripheral arterial tonometry (PAT), which provides information about blood flow to signal when a person experiences a lapse in breathing. Whereas WatchPAT equipment needed to be returned to the sleep clinic, the WatchPAT One released in 2019 is the first disposable home sleep test.
Home Sleep Test Metrics
The types of measurements collected by a home sleep apnea test depend on the test type. To qualify as a type 3 test, a HSAT must measure:
- Two breathing-related measures, such as airflow and breathing effort
- Blood oxygen level
- One heart-related measure, such as heart rate
Type 4 tests collect one or two measures, which may include:
- Blood oxygen level
- Heart rate
Other measurements may be collected, such as snoring frequency or volume, and body movements.
The current sleep test categorization system does not account for certain measurements obtained by alternative tests, like the ARES or WatchPAT. Therefore, a new system for evaluating sleep tests has been proposed. This system’s name is an acronym — SCOPER — for the measurements it includes, which are those related to sleep, cardiovascular, oximetry, position, effort, and respiratory activity.
People undergoing a home sleep apnea test should be aware that most of the time, these tests are not capable of identifying patterns of sleep versus wake. They only measure breathing and collect other data that can help diagnose sleep-disordered breathing when interpreted by a sleep specialist.
How Does a Home Sleep Study Work?
A home sleep apnea test can vary depending on who orders or administers it. The process generally involves meeting with a medical professional, receiving the equipment and carrying out the test at home, and then meeting again with your doctor to discuss the results.
- Meet With Your Doctor: If you are experiencing symptoms of OSA or another sleep disorder, make an appointment with your doctor. You might consider bringing in a sleep diary that contains a record of your sleeping habits. If your doctor thinks you could have sleep apnea, they will refer you to a sleep specialist or sleep clinic.
- Meet With Your Sleep Specialist: The sleep specialist asks more detailed questions before determining next steps. You may ask them questions about home sleep apnea testing and how it compares to polysomnography in terms of cost, insurance coverage, convenience, and accuracy. If they think home sleep apnea testing is right for you, they will order the test.
- Obtain Home Sleep Apnea Test Equipment: Either someone will call you, or your sleep specialist will instruct you to contact a sleep lab or clinic to obtain the necessary equipment for your test. When they give you the equipment, staff will walk you through how to use each device.
- Carry Out the Test: Once you have the equipment, you can carry out the test. Follow the instructions provided as you put on any sensors, such as a pulse oximeter on your finger, nasal cannula in your nostrils, and a band around your chest. Try to go to sleep and wake up at your normal times and avoid caffeine and alcohol, as they can affect your sleep. If you usually take sleep medications, ask your doctor if it is appropriate to take them the night of the test.
- Return the Equipment: Return your equipment at the time and to the location predetermined by your medical providers, unless you have a disposable test such as the WatchPAT One. Once the sleep lab or clinic receives the equipment, they will download and analyze the collected data. The American Academy of Sleep Medicine recommends this be done manually by a trained specialist instead of relying on algorithms.
- Learn the Results: Once the data has been analyzed, your doctor or sleep specialist will discuss the results with you. They might give you a sleep apnea diagnosis and prescribe treatment such as a continuous positive airway pressure (CPAP) machine. Alternatively, they might inform you that your results were negative or inconclusive. In the case of negative or inconclusive results, you might be asked to undergo an in-lab sleep study.
Home Sleep Studies vs. In-Lab Sleep Studies
Home sleep tests are only used to diagnose sleep-disordered breathing issues, like sleep apnea. By contrast, in-lab sleep studies can help diagnose other sleep disorders, like narcolepsy and periodic limb movement disorders. The difference lies in what the tests measure. Although both tests usually measure factors like airflow, blood oxygen levels, and heart rate, only in-lab sleep studies actually measure sleep by monitoring brain activity.
People often prefer a home sleep study to an in-lab study, since it is less expensive and does not require traveling to the sleep lab. A home sleep apnea test also involves fewer attached devices, so it may feel less invasive. However, since an in-lab sleep study gathers more data, it is more likely to pick up on symptoms of obstructive sleep apnea or other conditions.
If you have a straightforward case of moderate or severe sleep apnea and no other health conditions, then a home sleep apnea test might be right for you. If you have any reason to believe you need a more comprehensive test, then it might be worthwhile to skip the home test and go directly to the sleep lab.
Talking to Your Doctor About At-Home Sleep Tests
If you believe you might have obstructive sleep apnea, you could bring up the possibility of home sleep apnea testing at your next doctor’s appointment. Usually, a primary care physician refers people who might have sleep apnea to a sleep specialist, and the specialist then determines what type of sleep testing is most appropriate.
Frequently Asked Questions
Ultimately, a sleep specialist is the one who should decide whether you fit the profile for a home sleep apnea test. However, it is helpful to understand the benefits and drawbacks. We share answers to common questions about home sleep apnea testing.
How Much Do Home Sleep Studies Cost?
From our own price comparisons, we’ve seen the cost of most home sleep apnea testing in the U.S. to fall between $150 to $500. Often, health insurance covers some or all of the cost. You may need to pay the deductible if you haven’t already.
How Accurate Are Home Sleep Apnea Tests?
Type 3 home sleep apnea tests are highly accurate at detecting sleep apnea in people considered likely to have a moderate or severe form. The test becomes less accurate for people with certain other health or sleep disorders.
How Many Times Can I Take an At-Home Sleep Apnea Test?
Generally, people only take a home sleep apnea test once. If that test is not enough to diagnose obstructive sleep apnea, they may be advised to do an in-lab, overnight sleep study.
What Sleep Disorders Can Home Tests Detect?
Home sleep apnea testing is only used to detect sleep-disordered breathing problems, like obstructive sleep apnea. Since existing home tests do not actually measure the brain waves of sleep, they are not capable of diagnosing other sleep disorders.
Will Insurance Pay for Home Sleep Apnea Studies?
Many health insurance plans cover home sleep apnea tests. The amount of coverage depends on the insurance company and the medical provider. Medicare Part B, for example, requires people to pay for 20% of study costs as well as the deductible, if applicable. To be covered by insurance, a test generally needs to be prescribed by a sleep specialist. You may want to confirm that your specific test falls under your insurance coverage before taking it.
Who Should Not Take a Home Sleep Study?
Although a home sleep test is useful for many people who may have obstructive sleep apnea, certain factors make it less accurate for others. Experts recommend an in-lab sleep study rather than a home study for people who are suspected to have:
- Congestive heart failure
- Severe or chronic pulmonary disease
- Neurological or neuromuscular disorders
- Other sleep disorders, like narcolepsy, parasomnias, or periodic limb movement disorder
A home sleep study may also be less accurate at detecting mild sleep apnea. If your sleep specialist suspects you have mild sleep apnea, they may recommend an in-lab study instead.
Is There a Downside to Home Sleep Testing?
For most people, the biggest risk of a home sleep apnea test is the potential for being misdiagnosed as not having obstructive sleep apnea when they actually have it, or as having a milder version than they actually do. For this reason, doctors often order an in-lab sleep study when a home sleep study comes back negative.
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