An in-lab sleep study or polysomnography (PSG) is a non-invasive, overnight exam that allows monitoring while you sleep to see what’s happening in your brain and body. For this test, you will go to a sleep lab that is set up for overnight stays—usually in a hospital or sleep center.
While you sleep, an EEG monitors your sleep stages and the cycles of REM and non-REM sleep you go through during the night, to identify possible disruptions in the pattern of your sleep. A sleep study will also measure things such as eye movements, oxygen levels in your blood (through a sensor—there are no needles involved), heart and breathing rates, snoring, and body movements.
