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Hearing screening programs identify children with hearing loss and help to ensure that speech, language, cognition, and learning are not delayed. Testing for otoacoustic emissions (OAEs) is an objective, non-invasive way to identify hearing defects in very young children who are unable to cooperate with conventional testing. OAEs are sounds generated by the movement of the outer hair cells in the inner ear, or cochlea, in response to an external sound like a tone or click. OAEs can be measured in the ear canals of normal hearing individuals, but are absent in those with a significant hearing loss (30 dB or greater). The screening tool tests for the presence or absence of these OAEs in response to a click. The test cannot determine the cause of hearing loss. Tympanometry is another test requiring specialized equipment that measures the mobility of the tympanic membrane (ear drum) and conduction bones by varying the air pressure in the ear canal. Although it does not assess hearing, it can help to identify fluid and negative pressure in the middle ear.
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