Polysomnography is a comprehensive sleep study used to diagnose sleep disorders. It records various body functions during sleep, including brain activity, eye movements, heart rate, and breathing patterns. This information helps healthcare professionals understand sleep stages and identify issues like sleep apnea or insomnia. During a polysomnography test, sensors are placed on the patient's body to monitor these functions overnight. The data collected is analyzed to provide insights into the patient's sleep quality and any disturbances that may occur. This test is typically conducted in a sleep clinic or hospital setting for accurate results.