Medical Terminology

polysomnography (PSG)

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Polysomnography (PSG), also called a sleep study, uses multiple electrodes and devices (multi-channel) to gather information about a patient during sleep. A standard in-laboratory study records brain waves, eye movements, oxygen levels in the blood, jaw movement, heart rate, breathing rate, airflow, respiratory effort, sound, and limb movements. Taken as a total picture, the results of these recordings allow a calculation of sleep stages and provide data that can help diagnose disorders of sleep. In contrast, limited-channel sleep studies usually take place outside of the sleep laboratory.