Patients suspected of having obstructive sleep apnea (OSA) will have to have a sleep study performed to properly diagnose the disorder. There are two possible tests for determining a diagnosis: an attended polysomnogram (PSG) and an unattended home sleep test (HST).
Attended PSG tests are conducted in a sleep lab under the supervision of a registered polysomnographic sleep technologist (RPSGT). In addition to sleep apnea, PSGs can diagnose up to 80 sleep disorders by using a variety of equipment that monitors brain activity, eye movements, respiratory effort, blood oxygen saturation, heart rate, body movements, and more.
HSTs on the other hand are used only in the diagnosis of sleep apnea, and are performed by the patients themselves. Patients taking a HST will bring home their equipment to use overnight after being given a tutorial on how to use the equipment. HSTs are very simple and easy to use. HSTs are also limited in the data they capture to respiratory effort, blood oxygen saturation, and airflow. Some HSTs can also capture breathing movement and body positions.
HSTs are increasingly being used in the determination of obstructive sleep apnea. However, there are some important considerations to make when choosing between having an in-lab sleep study and an at home sleep test. Here we explain those considerations.
Benefits of Home Sleep Tests
Before we dive into some of the challenges of home sleep testing, it's important to talk about the benefits that HSTs have provided for sleep medicine.
Cost convenience. HSTs are much more affordable than PSGs. At about 1/4 of the cost, HSTs are an attractive alternative to PSGs to both insurance companies and patients paying out of pocket. Many insurance companies are requesting an HST as the first-line for diagnosing sleep apnea.
Comfort and accessibility. Being able to have a sleep test in the comfort of one's own home makes it more convenient for patients who either don't like the idea of staying overnight in a lab, live in a remote location, or have other medical problems that could prevent them from sleeping in a lab.
Scheduling. It's a lot easier to have patients show up to a facility and receive a HST device, than it is to fill beds. Sleep labs can only see as many patients each night as they have beds. Sleep clinics also have to have sleep technologists on staff to monitor the study. Most sleep technologists work with two patients per night, although three patients in a night can be done.
Good tool for high risk OSA patients. Patients found to be at high-risk for sleep apnea based on medical history, family history, and a physical evaluation are good candidates for HSTs. Signs to look for in high risk patients include the patient's BMI, neck size, age, craniofacial anatomy, and upper airway evaluation. For properly screened patients, the HST is designed to determine the severity of sleep apnea, not just the existence of it.
What are the challenges of Home Sleep Apnea Testing?
While there are many benefits to using HSTs to diagnose sleep apnea rather than going through the traditional polysomnogram test, there are some challenges that patients and medical professionals should be aware of.
HSTs are not as accurate and therefore tend to under. Much less equipment is used during an HST, most notably of which are EEG electrodes to monitor brainwave activity. Sleep apnea often becomes worse as one enters deeper stages of sleep. In a PSG, a patient's apnea/hypopnea index (pauses in breathing/decreases in breathing) is only recorded during REM stages of sleep (when they are at their worst and most frequent). HSTs record the entire night, and cannot adequately determine when the patient is awake, or if asleep, what stage of sleep the patient is in. This makes it nearly impossible to get an exact pressure needed for a CPAP machine, which is why most patients who have a HST will end up on APAP machines. APAP machines have a range of pressures (a minimum and maximum pressure which it fluctuates between) rather than a fixed pressure.
HSTs are not ideal for patients with other sleep disorders. Because PSGs include much more monitoring equipment, they can detect the existence of other sleep disorders that may be affecting a patient's sleep. Many patients have more than one sleep disorder. An HST will not pick up on the presence of restless leg syndrome, periodic leg movement disorder, bruxism, narcolepsy, or any number of other disorders.
HSTs are not ideal for patients with other medical problems. Patients with chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), neuromuscular diseases, and others are not good candidates for HSTs.
HSTs are not monitored. While not having a sleep tech watching as one sleeps may seem appealing, many patients can accidentally turn off or knock loose a sensor during the test. In an in-lab study, a sleep tech would be alerted to the disconnection and quickly reattach the sensor. In a home sleep test, the missing recorded information may not be caught until well after the test has been completed and an interpretation is being done. Patients that turn off the machine or disconnect equipment before enough data has been recorded for a complete study may have to retake the test at later date.
While it's true that there are some issues with choosing a HST over a PSG to diagnose sleep apnea, there's no denying the many benefits that HSTs are bringing to the field of sleep medicine.
Because of the low cost, accessibility, and convenience of use for patients, more people than ever are finally getting their sleep apnea diagnosed and treated. And as long as medical professionals are properly screening their patients for comorbidities, evidence of other sleep disorders, and giving proper patient education on use of HST devices, HSTs will continue to grow as an important diagnostic tool in determining sleep apnea.
If you suspect you have sleep apnea, and want to see if a home sleep test is right for you, contact The Alaska Sleep Clinic for a free 10-minute phone consultation by clicking the link below.
If you would like to know more about the various sleep tests used in diagnosing sleep disorders, download the free ebook below.