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Physiology of hearing and hearing loss

Question
1 out of 39
 

Otoacoustic emissions arise from: [AIIMS May 09; AI10]



A Inner hair cells

B Outer hair cell

C Both inner and outer hair cells

D Organ of Corti

Ans. B Outer hair cells

Otoacoustic Emissions (OAEs)

Otoacoustic emissions are acoustic signals emitted from the cochlea to middle ear and into the external ear canal where they are recordeD.

They are low intensity sounds probably generated by acute mechanical contraction of the outer hair cells

They are produced either spontaneously or in response to the acoustic stimuli

Sound produced by outer hair cells moves in reverse direction viz:

Outer hair cell ~ Basilar membrane PerilymphOval window Ossicles Tympanic membrne Ear canal.

OAEs are present when outer hair cells are healthy.

Abscence of OAE indicate structurally damaged or non-functional outer hair cells.?

They do not dissappear in eighth nerve pathology as cochlear hair cells are normal."

Uses

a. OAEs are used as a screening test of hearing in neonates and to test hearing in uncooperative or mentally challenged individuals after sedation. Sedation does not interfere with OAEs.

b. They help to distinguish cochlear from retrocochlear hearing loss as they are absent in cochlear but not in retrocochlear leisons.

c. OAEs are also useful in diagnosing retrocochlear pathology, especially auditory neuropathy.

Extra Edge

Type of OAE - Broadly OAEs are of 2 types

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Physiology of hearing and hearing loss Flashcard List

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