Home Sleep Study
A home sleep test is a diagnostic test that can determine whether or not you have Obstructive Sleep Apnea (OSA). It involves the use of a portable-monitoring system that is small enough for you to use at home. The system consists of a small recording device, sensors, belts, and related cables & accessories.
The sleep recorder gathers important data as you sleep in your own bed. It receives information from sensors that are applied to strategic locations on your body. For example, sensors near your nose and mouth may measure your airflow. Other sensors around your chest and stomach may measure your breathing effort.
Each sensor sends a signal that is recorded on its own "channel." Some home sleep tests collect more information than others. A system with a higher number of channels collects more data. A home sleep test can have as few as one or two channels, or as many as seven or more.
A home sleep study calculates the number of hypopneas and apneas that you experience. Partial reductions in breathing are called "hypopneas." Total pauses in breathing are called "apneas." In adults each of these events lasts for at least 10 seconds. A home sleep test that measures airflow will calculate the number of hypopneas and apneas that you experience. Having a combined total of 30 or more hypopneas and apneas within two hours indicates that you have OSA.
The best way for a home sleep test to measure airflow is with a combination of these two methods:
●Thermal sensors that you place near your nose and mouth. These sensors detect changes in temperature as you breathe in and out. Air that you exhale is warmer than the air that you inhale.
●A cannula with a nasal pressure transducer. The cannula is a flexible tube that is inserted into your nose. The nasal pressure transducer is sensitive to minor changes in airflow. But it only measures nasal airflow; it does not measure the flow of air into and out of your mouth.
Home sleep tests often measure breathing effort because OSA involves pauses in breathing that occur even though your body continues making an effort to breathe. In contrast, a pause in breathing with no effort to breathe is a sign of central sleep apnea. The most effective way to measure breathing effort is by a technique called "respiratory inductance plethysmography" (RIP). This involves belts that you wear around your chest and stomach. These belts contain sensors and wires that carry a small electrical current. Chest or stomach movements produce changes in the current.
Blood oxygen level is another common measurement because episodes of OSA may cause a decrease in the level of oxygen in your blood. This level is also known as "blood oxygen saturation." It is measured using a pulse oximeter on your fingertip.
Who gets it?
A home sleep test is for people who are at risk for OSA. Home sleep tests are not used to detect other sleep disorders.
Key risk factors for OSA include loud and frequent snoring, excessive daytime sleepiness, obesity, hypertension, and witnessed pauses in breathing during sleep. Complete this questionnaire to learn more about the risk factors for OSA.
Even if you are at risk for OSA, your doctor may decide that at overnight sleep study at a sleep disorders center is a better option for you. If you have another major medical problem or sleep disorder, then an overnight sleep study may provide more accurate results. Home sleep tests are not recommended for children.
Your doctor also may use a home sleep test to evaluate your response to some OSA treatments. These include weight loss, oral appliances and surgery.
What happens when I have it?
You will receive the equipment and instructions that you need. At home you should carefully read any instructions that you received with the recording system. Shortly before your normal bedtime, complete the set up of the equipment. Follow the instructions to ensure that the system functions properly. Then get in bed and go to sleep.
At your normal wake time, remove the sensors according to the instructions. Then return the recording system to your doctor's office.
Who reads it?
The home sleep test records your body's activity during sleep. It then converts these recordings into visible tracings that can be measured and analyzed. Computer software can help perform some of the basic analysis, or "scoring," of this data. Our board-certified sleep specialist will review the data and prepare a summary report for your doctor.
How do I get the results?
Your doctor will discuss the results of the home sleep test with you. A "positive result" is a strong indication that you have OSA. In this case the doctor will develop a treatment plan for you.
A "negative result" may indicate that you do not have OSA. But home sleep tests can produce a negative result even when you have OSA. This is called a "false negative result." About 10 percent of people with OSA are likely to receive a false-negative result. This can occur for a variety of reasons. One common cause is data loss. Critical data may be lost if the equipment malfunctions or is set up improperly.
If you get a negative result, then your doctor may schedule you for a Split Night Sleep Study at the RCH Sleep Center. This study will record more information than the home sleep test. It also will be attended by our trained technician who will monitor your equipment during the night.