Introduction
An at-home sleep test aims to diagnose obstructive sleep apnea (OSA) in the population under treatment. The condition is quite severe, even though around twenty-four million Americans live with it without realizing that they have it (Okoye, 2022). According to Sleep Foundation data, an estimated 10% to 30% of adults have OSA, but the condition often remains undiagnosed (Summer, 2022). During OSA, an individual’s airway collapses several times during each hour of sleep, causing a brief stop in breathing. As a result of the lapses in inspiration, a person experiences snoring, sleepiness in the daytime, issues focusing, as well as possible headaches in the morning. In addition, the condition comes with a higher risk of other health problems, such as stroke and heart attacks. At-home sleep testing represents a cost-effective alternative to diagnosing obstructive sleep apnea in patients and is an acceptable method that can be used in the comfort of patients’ homes.
Purpose of Testing
An at-home sleep apnea test is among the types of studies used for detecting the condition. It represents an overnight test implemented outside a hospital or a sleep laboratory. The test is referred to as a home sleep test (HST), an out-of-center sleep test (OCST), an out-of-center (OCC) recording, or a polygraph (PG). According to the findings of Saletu et al. (2018), at-home sleep testing for sleep apnea has good reliability and validity due to the high sensitivity of the devices being used. The median predictive value of such tests has been estimated at 72%, which indicates that the test could be used in the majority of instances when a sleep apnea diagnosis is necessary (Harris & Swinson, 2017). Notably, the sensitivity of HST through home portable devices was estimated at 90% or more (Harris & Swinson, 2017). Therefore, there are little sensitivity issues that apply to such tests. It is notable that while HST can only accurately diagnose OSA in some patients, which means that it does not apply to all, the test carried out at home is more affordable and is seen as a more convenient alternative to in-lab research.
Testing Process
When a patient undergoes sleep testing at home to diagnose sleep apnea, they are required to pick up special equipment from the doctor’s office or a sleep clinic. Then, they are required to carefully follow the instructions on how to use the devices and equipment to successfully measure the necessary indicators. A patient sleeps as they would usually do only with the devices connected to them for at least one night. After the data is collected, a sleep specialist will analyze the data to determine whether the patient meets the criteria for OSA.
Tools of Measurement and Parameters
Specific biological parameters measured during HSTs include nasal and oral airflow, respiratory effort, and oxygen levels. To measure the nasal and oral airflow, a thin wire (a breathing sensor) is tapped by the patient’s nose and mouth to monitor the airflow throughout the night. The breathing patterns are analyzed by tracking the pressure of air when a person is inhaling and exhaling. In some cases, instead of a traditional breathing sensor, an oronasal thermistor (a temperature sensor) is used, placed between the nose and the mouth. This device may be necessary for patients who do not breathe through their noses during sleep.
Respiratory effort is measured with the help of elastic belt bands placed across a patient’s chest and abdomen. The effort belts allow for attaining data that can help differentiate between obstructive sleep apnea, in which a person is making an effort to breathe, versus central sleep apnea, in which the brain fails to send the signal to inhale and exhale, and thus there is no movement. In addition, the effort belt is used for securing the box storing the data that is being collected from all sensors used in the testing.
Oxygen levels are measured using a clip-like device, a pulse oximeter, that is attached to the fingertip, emitting a red light that helps in evaluating the levels of oxygen in the patient’s blood when they are sleeping. In some cases, the pulse oximeter may be connected to an earlobe instead of a finger. While a nasal breathing sensor is used for estimating snoring, sometimes an actual microphone is used. Finally, a data collection device is used to start and stop the test, as well as indicate that all devices are connected and powered to collect information for testing.
Conclusion
The metrics collected by a home sleep apnea device depend on the type of test being used. Types 1 and 2 tests tend to collect more in-depth data, while home tests are typically types 3 and 4, which means that they would collect less data. For qualifying as a type 3 test, an HST must measure two breathing-related measures, which include airflow and breathing effort, blood oxygen level, and one heart-related measure, such as the heart rate. In type 4 tests, one or two measures are collected, which may include airflow, blood oxygen levels, and heart rate. Besides, depending on each patient’s case, other measurements may be collected, such as the snoring frequency, volume, and body movements during sleep.
References
Harris, L., & Swinson, K. (2017). Home sleep testing for diagnosing obstructive sleep apnea. American Family Physician, 96(1). Web.
Okoye, A. (2022). At-home sleep apnea tests. The Sleep Doctor. Web.
Saletu, M. T., Kotzian, S. T., Schwarzinger, A., Haider, S., Spatt, J., & Saletu, B. (2018). Home sleep apnea testing is a feasible and accurate method to diagnose obstructive sleep apnea in stroke patients during in-hospital rehabilitation. Journal of Clinical Sleep Medicine, 14(9), 1495–1501. Web.
Summer, J. (2022). At-home sleep study. Sleep Foundation. Web.