Anyone suspected of having obstructive sleep apnea (OSA) generally will be asked to undergo a sleep evaluation. Some evaluations can be done at home using portable equipment, but the most thorough evaluations are conducted by professionals in a sleep lab, where you will go to spend the night.
A sleep study also goes by the name polysomnogram test, or PSG for short. The PSG records specific physical activities while you’re sleeping. Here are four different sleep tests and what they’re used for:
- A diagnostic overnight PSG collects data involving your breathing patterns, limb movements, heart functioning and the oxygen levels in your blood. This means you will spend the night in the lab sleeping and being monitored.
- A two-night diagnostic PSG and CPAP (continuous positive airway pressure) titration is basically the same as the overnight diagnosis, but if sleep apnea is detected, you may be asked back for another night to see which level of CPAP airflow works best for you.
- A split-night PSG with CPAP titration shortens everything into one night when sleep apnea is detected during the first half of your sleep. You will be awakened and then fitted with a CPAP mask and tested for proper airflow.
- A diagnostic daytime multiple sleep latency test (MSLT) is used to diagnose narcolepsy and daytime sleepiness. The MSLT is generally conducted the morning after a PSG and measures how quickly you fall asleep in quiet situations. It also measures how quickly you fall into REM (rapid eye movement) sleep.
In the sleep lab, which may or may not be part of a hospital, you will be fitted with various devices to do the measuring. Though the monitoring attachments may appear uncomfortable, most people have no trouble falling asleep. Typically, the monitoring will be done remotely in an adjacent room. If you are advised to get one of the tests above, your doctor and his or her staff will explain the details to you in advance.