Which statement about otoacoustic emissions (OAE) testing is true?

• A. OAE testing screens for brainstem lesions
• B. OAE testing measures tympanic membrane mobility
• C. OAE testing is only used for adults
• D. Normal hearing produces OAE

Answer: (D)

Otoacoustic emissions come from the cochlea, specifically the outer hair cells. When the cochlea is functioning and the middle ear is transmissive, presenting a sound stimulus makes the outer hair cells respond and generate a tiny echo back into the ear canal. A sensitive microphone in the ear canal can detect this emission. The presence of these emissions indicates healthy outer hair cell function and, typically, normal hearing within the tested range. If hearing is impaired due to cochlear damage, OAEs are often absent or reduced. OAEs do not screen for brainstem lesions (that requires other tests like auditory brainstem response) and are not a measure of tympanic membrane mobility (that’s the job of tympanometry). They’re applicable to both infants and adults, not restricted to one age group. So the true statement is that normal hearing produces OAE.