Polysomnography

Polysomnography, abbreviated PSG, is a multi-parameter type of sleep study and a diagnostic tool in sleep medicine, with the test result called a polysomnogram. Type I polysomnography is a sleep study performed overnight with the patient continuously monitored by a credentialed technologist, recording the physiological changes that occur during sleep, including brain activity, eye movements, skeletal muscle activation and heart rhythm. After the sleep disorder sleep apnea was identified in the 1970s, monitoring of breathing functions, respiratory airflow and respiratory effort, along with peripheral pulse oximetry, was added to the standard test.