Otoacoustic Emissions measure the inner ear’s hair cell function. An emission is a sound produced within the cochlea when it is stimulated, which causes the outer hair cells to vibrate. The vibration creates a very soft sound that causes the cochlea to echo in response to the sound. Small probes are inserted into the ear, which measures the sound.
People with a hearing loss greater than 25-30 db cannot produce these soft sounds. This test is often used to detect deafness for newborn babies and hearing loss for adults.