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Blog Feature

By: Rita Brooks on January 4th, 2018

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What Is Polysomnography?

Sleep Technologist Advice

Polysomnography is a test conducted to study sleep and to diagnose a variety of sleep disorders. Some people refer to polysomnography (PSG) as a sleep study. Sleep technologists perform the tests which are typically conducted in hospitals, free-standing facilities, or dedicated sleep clinics.

For patients concerned about pain or discomfort, it is important to reassure them that the procedure is non-invasive, and complications from the PSG itself are rare.

What is the Purpose of Polysomnography?

Polysomnography is used not only to help diagnose a variety of sleep disorders, but also to learn whether adjustments to treatment plans are needed or if the current treatment plan is effective. The sleep study itself provides specific information to sleep technologists (through equipment and observation), including:

  • Blood Oxygen Levels
  • Brain Waves (EEG)
  • Breathing Rates and Patterns
  • Body Positioning
  • Eye Movements
  • Heart Rates and Rhythms
  • Leg Movements
  • Sleep Stages
  • Snoring and Noises Made While Sleeping
  • Unusual Movements or Behaviors

Of course, all of this is done while patients are sleeping. Once the information is gathered, as a sleep technologist, you will often be the first to evaluate and chart the information gathered during the PSG test.

Some of the sleep disorders polysomnography may diagnose include:

  • Bruxism
  • Central Sleep Apnea
  • Circadian Rhythm Sleep-Wake Disorders
  • Complex (or Mixed) Sleep Apnea
  • Idiopathic Hypersomnia
  • Narcolepsy
  • Obstructive Sleep Apnea
  • Periodic Limb Movement Disorder (PLMD)
  • REM Behavior Disorder (RBD)
  • Parasomnias 

While this list is not exhaustive, it does represent many common sleep disorders the patient’s physician may be concerned about verifying (or ruling out).


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When Should Polysomnography be Performed?

Physicians order polysomnography for many different reasons, including concerns that the patients may be experiencing one of the following:

  • Sleep Apnea
  • Periodic Limb Movement Disorder
  • Narcolepsy
  • REM Sleep Behavior Disorder
  • Unusual Behaviors During Sleep
  • Unexplained Chronic Insomnia

Your job, as a sleep technologist is to make the patients as comfortable as possible during the sleep study. You’ll also record the results and your observations accurately so that you can work with the doctor to coordinate an accurate diagnosis and effective treatment plan.

How Should You Prepare Your Patient for a Polysomnography?

There are different things you can do prior to the night of the polysomnography to help prepare your patient for the test, as well as things you can do on the night of the test to put patients at ease for the test.

One important thing you need to do is inform patients to abstain from alcohol and caffeine during the afternoon and evening preceding the polysomnography. Prepare your patient for the fact that this is an overnight test, and encourage your patient to bring items essential to their bedtime routines as well as his or her pajamas – so your patient can sleep comfortably.

Patients may have a little difficulty falling asleep due to being in unfamiliar surroundings, a little bit of nervousness, and the electrodes and wires may make getting comfortable a little more challenging than normal. Encourage them to bring a book to read or something soothing to help them relax before sleep.

Let the patient know your role in the sleep study by explaining that you will monitor their brain waves, eye movements, heart rates, breathing patterns, sleeping positions, limb movements, blood oxygen levels, and snoring and other noises they may make while sleeping.

Explain to your patient that you will study those things by watching the recordings while he or she sleeps that are generated by tiny sensors on his or her scalp, chest, and legs, as well as a sensor that attaches to the tip of the patient’s finger to monitor blood oxygen levels.

These sensors and electrodes are attached to wires that send important data to the computer – details that you cannot simply observe in patients – so you can study them later.

What do the Results of a Polysomnogram Mean?

One of your roles as a sleep technologist is to score and chart the sleep stages and events recorded for the doctor to review. Your observations during the study are critical in helping the sleep physician identify certain conditions, which means you need to make note of observations such as disruptions during various sleep stages, identified by brain waves and eye movements, that may indicate REM Sleep Behavior Disorder or Narcolepsy. You may also notice heart and breathing rate changes along with changes in blood oxygen levels indicative of sleep apnea.

Other observations may include frequent leg movements that might signify periodic limb movement disorder or unusual movements and noises during sleep that signal the possibility of REM Sleep Behavior Disorder.

There are many possibilities that can only be discovered with the powerful combination of a skilled sleep technologist and the information gathered by the electrodes and sensors attached to patients.

Key Takeaways

These are a few key things to note about polysomnography and your role:

  • Polysomnography testing is typically conducted in hospitals, sleep clinics, or free-standing facilities.
  • Sleep studies are essential tools for helping to diagnose and determine treatment effectiveness for a variety of sleep disorders.
  • PSG is a non-invasive procedure that monitors sleep stages and cycles, as well as limb movement, breathing and cardiac parameters, and more.
  • Patients should refrain from drinking alcohol and caffeine in the hours leading up to the polysomnography and are encouraged to bring along things that promote their traditional bedtime routines – including pajamas so they can sleep comfortably during the study.
  • Sleep technologists perform the test and monitor brain wave activity, eye movements, heart rates, breathing patterns, body positioning, sounds, movements, and blood oxygen levels throughout the recording.
  • Sleep technologists deliver the tabulated results of the sleep study to physicians to help successfully diagnose sleep disorders.

Whether you are just getting started in your career as a sleep technologist or have many years of experience in the field, you will find Sleep Technology Terms and Definitions, a free gift from the American Association of Sleep Technologists (AAST), is an invaluable tool for helping you communicate clearly and effectively with other professionals in your field.

Sleep Technology Terms and Definitions