Otoacoustic emissions testing (OAE) measures the inner ear's response to sound. A small microphone placed in the ear canal measures the response of the cochlea. The patient will hear a series of very soft tones. A normal hearing ear will send the sound back out and record it while an ear that has hearing loss will not. OAE testing does not require the patient to respond. It can be used to assess the hearing of adults and children. It is often used to screen the hearing of newborns.