OAEs are a physiological test for identifying hearing loss. They assess the function of the outer hair cells located in the inner ear (organ of hearing). For this test, a soft probe tip is placed in the ear canal. A series of clicks or tones are delivered through the probe tip and the probe measures and records a response from the inner ear. In a normally functioning ear, when the click is presented, a very soft echo-like sound is created by the inner ear and is measured by the probe. Because the sound being measured in the ear canal is so soft, it is necessary that the patient by as still and quiet as possible during testing. For infants it is recommended that they are asleep during testing. With patient cooperation, the entire test can be completed in 5-10 minutes. This test is commonly used for newborn hearing screenings.