*Nothing in this article constitutes medical advice. Seek the guidance of a physician if you have any questions.*
Sleep tests, also known as Polysomnography, are an extremely valuable diagnostic tool. They can help you and your physician make important treatment decisions will can affect your sleep quality and, thus, your overall quality of life. Today, let’s take a deeper dive into a lesser-known type of sleep test: the at-home exam.
Sleep Test Goals
A sleep test will typically be ordered by your primary care physician. They will generally refer you to a somnologist - a sleep doctor - who will actually carry out the test or give you instructions on how to administer the test at home. There are many reasons that a physician may suggest a sleep study. Usually, this is because your physician suspects you may have a sleep-related disorder. Here are a few things your physician may be screening for.
- Sleep apnea: This disorder (and many other breathing disorders associated with sleep) is characterized by many “starts and stops” while breathing. There are several different underlying conditions that can manifest sleep apnea, but they all can severely damage sleep quality.
- REM sleep behavior disorder: Individuals affected with this disorder experience the physical acting out of dreams that a person is experiencing. This can be detrimental to not only their sleep but the sleep of those sharing a bed or room with that person.
- Periodic limb movement disorder: PLMD is a condition in which an individual involuntarily flexes and tenses their legs (and sometimes arms) while sleeping. It is often associated with restless leg syndrome, and, like sleep apnea, can be very detrimental to sleep quality.
- Narcolepsy: Patients with narcolepsy experience sudden, intense drowsiness and are prone to fall asleep involuntarily.
Unexplained, unusual sleep behaviors: As a catch-all, your physician may prescribe a polysomnography if you’re experiencing any kind of unusual sleep behavior that doesn’t fall into one of the above categories. This could be anything from sleep-walking to adult bed-wetting.
- Chromic insomnia: Many of the above conditions can results in either acute or chronic insomnia. If a patient is experiencing unexplained chronic insomnia, it can also warrant a sleep test
Laboratory Sleep Test
In order to better understand what an at-home sleep test may look like, we first should cover the basics of what a laboratory sleep test entails. The process can be divided into three steps: before, during, and after.
Prior to a laboratory examination, your physician will likely give you an instruction packet that details all the steps you’ll need to take. For a full somnography, the “laboratory” will look somewhat similar to a hotel room. There are likely to be cameras, microphones, speakers, and medical equipment at different locations in the testing room. These all allow the doctors to monitor your sleep.
Your physician is likely to remind to to avoid any sleep-altering drugs before the exam such as alcohol, caffeine, or sleep aids. This will ensure that the test is representative of your normal, unaltered sleeping conditions.
During the Exam
One of the main aims of the exam is to better understand a patient’s movements and behaviors during sleep. Because of this, before the exam a technician will place a variety of sensors on your body, typically on your head, chest, and legs. While you sleep, many different readings and measurements are taken. These aim to understand a variety of factors, including:
- Heart rate
- Brain waves
- Eye movements
- Body position
- Breathing pattern
- Blood oxygen level
- Snoring or other noise
- Limb movement
- Chest and abdominal movements
The exam ends in the morning when you wake up. A technician will remove all sensors and you will schedule a follow up appointment with the somnologist to discuss the results. Some of the things your physician may discuss include:
- Eye movements and brain waves
- Heart and breathing rate
- Frequent leg and limb movements
- Any other unusual movements or behaviors
At-Home Sleep Tests
Now that we better understand in-lab somnology, let’s compare and contrast it with an at-home sleep test. Notably, one of the biggest differences between a lab test and an at-home test is cost. At-home tests usually cost from 25-40% of a lab test.
Before undergoing an at-home sleep exam, your primary care physician will need to prescribe one for you - just like a lab test. There are a variety of reasons that a physician may choose a lab test or an at-home test, but that is outside the scope of this article.
Unlike a laboratory exam, you will likely need to pick up the equipment that will be used during the study. This will almost always involve a continuous positive airway pressure machine (CPAP) as well as a variety of sensors. Prior to the study, a technician will walk you through the correct way to set up and use the equipment.
Similar to a lab exam, you should refrain from any substances which may alter your sleep patterns.
During the Exam
This is where the at-home and in-lab exams really differ. Most at-home tests involve only a CPAP machine and an oxygen sensor placed on your fingertip. The same level of sensors (on the scalp, chest, etc) are not usually utilized. First, you’ll place the mask over your face (following the technician’s instructions), then place the oxygen sensor on your finger. If the equipment becomes tangled or stops working, you will be responsible for untangling and fixing the problem.
After the exam, the equipment will need to be returned back to facility from which you picked it up. At this time, you’ll typically schedule a follow up appointment, similar to the in-lab exam (unless you had already done that). The somnologist will discuss many of the same things, but the data about brain waves and body movements will obviously be missing.
As we’ve seen, at-home and lab tests vary according to a few key metrics: cost, location, and results. While you, ultimately, have the final say in which exam you will undergo, the discussion should be between you and your healthcare provider.