All are true about otoacoustic emissions except:
Ans. A. OAEs are auditory evoked potentialsExplanationOAEs are low-intensity sounds that are generated by the cochlea either spontaneously or evoked by an auditory stimulus and propagate through the middle ear into the ear canal.OAEs are by-product of active processing by the outer-hair cell system. OAEs are present when outer-hair cells are healthy and absent when outer-hair cells are damaged. Thus, OAEs reveal, an incoming the integrity of outer-hair cell function.OAEs are biological phenomenon generated in normal cochlea when cochlea processes incoming auditory impulse. This is a mechanical activity taking place in outer hair cells before the inner hair cells transducer the mechanical activity into action potentials.are sounds, they are measured in decibels (dBSPL).It is a preneural activity and there are no action potentials generated. OAEs are not auditory evoked potentials.There are two broad categories of OAEs: spontaneous and evoked.Transient evoked OAEs (TEOAEs). Evoked by clicks. A series of click stimuli are presented at 80-85 dBSPL and response recorded.Distortion product OAEs (DPOAEs). Two tones are simultaneously presented to the cochlea to produce distortion products. They have been used to test hearing in the range of 1000-8000 Hz.UsesOAEs 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.They help to distinguish cochlear from retrocochlear hearing loss. OAEs are absent in cochlear lesions, e.g. ototoxic sensorineural hearing loss. They detect ototoxic effects earlier than pure- tone audiometry.OAEs are also useful to diagnose retrocochlear pathology, especially auditory neuropathy. Auditory neuropathy is a neurologic disorder of CN VIII. Audiometric tests, e.g. SNHL for pure tones, impaired speech discrimination score, absent or abnormal auditory brainstem response, show a retrocochlear type of lesion but OAEs are normal.
OAEs are auditory evoked potentials
Measured in decibels (dBSPL)
Can be seen during sleep
Low intensity sounds
Ear