Polysomnography, also called a sleep study, is a comprehensive test used to diagnose sleep disorders. Polysomnography records your brain waves, the oxygen level in your blood, your heart rate and breathing, as well as your eye and leg movements, during the study.
Polysomnography may be done at a sleep disorders unit within a hospital or at a sleep center. While it’s typically performed at night, polysomnography is occasionally done during the day to accommodate shift workers who habitually sleep during the day.