What really happens in a sleep lab?
So, your doctor decided that you need to have a sleep study. What does that actually mean?
Understanding what happens during a sleep study can help ease your concerns. I should know. I’ve worked as a sleep technologist for many years, and I’ve also undergone sleep studies both at home and in a lab setting. Below is my best advice and information about what you can expect to happen during the study, what it will measure, and how it can benefit your health afterwards.
There are two main types of sleep tests:
- Polysomnogram (PSG) Test This is what may come to mind when you think of a “classic” sleep study. Performed in a laboratory setting, this is the kind of test where you stay overnight. The PSG test evaluates both your sleep and your breathing.
- Home Sleep Test (HST) - The other type is a home sleep test, which is done at home and monitors how well you breathe during sleep.
Let’s focus on the experience you can expect in an in-lab PSG test.
Most lab rooms are arranged to mimic a hotel room. Some rooms lack windows, which may seem strange, but this is because some sleep studies are performed during the day, so the rooms need to be dark.
Once you are in the lab, the night sleep technologist will help you get adjusted to your surroundings. Some people bring their own pillow and other comfort items. If you are currently undergoing any special treatment for sleep involving an oral appliance or a CPAP, be sure to bring those as well. The technologist may choose to monitor you with or without them, or perhaps perform what is known as a split night study. This type of study monitors how your sleep differs with and without the use of your breathing aids.
Plan to wear what you normally wear at night for bed. You will have a private space to change and will also have access to a bathroom in case you need it. The technologist also might have you fill out some paperwork and questionnaires.
Once you are ready, the sleep technologist will guide you through the preparatory procedures.
- Your head is measured to aid in the placement of the electrodes to measure your brain activity. An electrode is a wire with a small “cup” or flat end. First the skin on your scalp is cleaned with an exfoliant. The cup end will be attached to your scalp with a special paste.
- More electrodes are placed on your chin and near your eyes. These will help monitor what kind of sleep you are having based on the movements of your facial features.
- The technologist places electrodes on your chest to monitor your heart, perhaps shaving certain areas of your chest beforehand if necessary.
- The technologist will place one band around your chest and one around the belly. These bands monitor how you breathe.
- You will most likely have a nasal cannula. This is special tubing that lays across the front of your nose on your upper lip area, and looks similar to what people use for supplemental oxygen. This cannula, however, measures the flow of air in and out of your nose. You will not feel anything blowing from it during your sleep test.
- Some laboratories measure snoring with a small microphone taped to your neck. This microphone will be placed on you right before bed.
- The technologist may place electrodes on the bottom front part of the leg to assess your leg movement during sleep.
- A pulse oximeter clip is placed on the tip of your index finger to measure how much oxygen is in your blood. This helps determine if you have breathing problems during sleep.
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All of the electrodes and wires will be plugged into a unit which takes the signals from your body and collects, reviews, and stores them onto a computer.
When you are ready for bed, the technologist shuts the lights off and closes the door. Then, they’ll communicate with you from another room over a speaker. One of the things they will ask you to do before you go to sleep is to do a series of calibrations so that the technology can “learn” what your natural movements are. You will be asked to look left and right, up and down, hold your breath, breath normally, and grit your teeth. The purpose of these calibrations is to aid in the interpretation of the information that will be collected.
Once the calibrations are complete, most patients are now ready to go to sleep. The rooms have infrared cameras which allow the technologist to view you while you sleep. These cameras also comes in handy if patients do activities like walking or talking in their sleep.
Sleep in the position you normally do. You won’t be woken up during your sleep lab by a technologist unless you are doing a split night study. Sometimes, the technologist might ask you to change sleep positions to compare the quality of your breathing, but most of the time people naturally move in their sleep and that kind of data can be collected on its own.
Expect to sleep for a minimum of six hours.
The next morning, the technologist will awaken you and remove all of the equipment. You may be able to shower before going home or heading to work.
Depending on laboratory practices, it may take up to a couple of weeks for you to get the results of your test. Technicians are not allowed to provide a diagnosis, give immediate results or feedback to the patients; this typically happens during a follow up appointment with your doctor. During this follow-up appointment, you will discuss the results of your lab as well as suggestions for therapeutic options.
Even though it’s just for one night, being a patient in a sleep lab can bring forth a wealth of useful information. When it’s complete, you and your doctor can continue to work together to make more informed choices about your sleep health.
Robyn Woidtke's entry into the sleep medicine world came through the neonatal field and conducting SIDS research at Stanford. In addition to her sleep background, she has extensive clinical affairs experience in medical device product development, clinical marketing, and the integration of sleep testing for clinical research professionals. Robyn is certified in Clinical Sleep Health and has been published in numerous respiratory, sleep, and clinical research journals. She has a Masters degree in Nursing and an undergraduate degree from The George Washington University.