Types of Sleep Studies Compared
Several kinds of sleep tests exist, and each answers a different question. Some diagnose breathing problems, some set CPAP pressure, and others measure daytime sleepiness. Your clinician chooses the test based on your symptoms and other health conditions.
| Test | Where | What it measures | Mainly used for |
|---|---|---|---|
| In-lab polysomnography (PSG) | Overnight in a sleep lab, attended by a technologist | Brain waves (EEG), eye movements, muscle activity, heart rhythm, airflow, breathing effort, oxygen, body position, leg movements | Diagnosing sleep apnea, especially with other medical conditions, and other disorders such as narcolepsy, parasomnias and periodic limb movements |
| Home sleep apnea test (HSAT) | At home, unattended | Usually airflow, breathing effort, oxygen and heart rate, without full EEG | Diagnosing obstructive sleep apnea in uncomplicated adults with a high likelihood of moderate to severe OSA |
| Split-night study | Sleep lab, one night | Diagnostic PSG in the first part of the night, then CPAP titration in the second part | Diagnosing and starting CPAP in one night when sleep apnea is clear early on |
| CPAP titration study | Sleep lab, overnight | Full PSG while a technologist adjusts PAP pressure | Finding an effective pressure, or choosing bilevel or ASV therapy |
| Multiple Sleep Latency Test (MSLT) | Sleep lab, daytime, usually after an overnight PSG | How quickly you fall asleep in 4 or 5 scheduled naps, and whether REM appears | Diagnosing narcolepsy and idiopathic hypersomnia |
| Maintenance of Wakefulness Test (MWT) | Sleep lab, daytime | How long you can stay awake while sitting quietly in a dim room over several trials | Assessing ability to stay awake, for example for safety critical jobs or treatment response |
Notes
- AASM guidelines say HSAT is not appropriate for some people, for example those with significant heart or lung disease, possible central apnea or certain neuromuscular conditions; they should have in-lab PSG.
- A negative or inconclusive home test in someone with symptoms should be followed by in-lab polysomnography.
- Medications and the prior night's sleep can affect MSLT and MWT results, so preparation instructions matter.
Frequently asked questions
Is a home sleep test as good as a lab study?
For uncomplicated adults with likely moderate to severe obstructive sleep apnea, AASM guidelines accept HSAT. It can miss milder disease and does not measure sleep stages, so a negative result with symptoms needs a lab study.
Does a sleep study hurt?
No. Sensors are attached to the skin with paste, tape or belts. Most people sleep reasonably well despite the wires.
What is the difference between the MSLT and MWT?
The MSLT asks you to try to fall asleep and measures how fast you do; the MWT asks you to try to stay awake and measures how long you can.
Sources
More reference tables
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