Are delayed evoked oto-acoustic emissions (DEOE) solely the outcome of an active intracochlear mechanism?
Post-mumps and post-measles hearing losses are a result of the destruction of Corti's organ. Both the basilar and the Reissner membranes are unimpaired. In 11 subjects with post-mumps (8 cases) and post-measles (3 cases) unilateral anacusis, DEOE with a mean amplitude lower than that of the contralateral normal ear with the same sensation level were observed with 0.5, 1 and 2 kHz tone-bursts and air conduction stimulation. These findings lend credit to the view that DEOE could in part be produced by a passive intracochlear mechanism, probably a consequence of the basilar membrane travelling wave induced by the displacement of the perilymph. In a normal ear, this passive mechanism could be superimposed by an active mechanism linked to the contractile activity of the outer hair cells (OHC) which modulates and increases the travelling wave depth.
Institute of Audiology, University of Turin, Italy.
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Rossi
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Solero
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Rolando
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Olina
D000293:Adolescent; D000328:Adult; D001489:Basilar Membrane / Q000503:physiopathology; D002648:Child; D003051:Cochlea / Q000503:physiopathology*; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008457:Measles / Q000150:complications; D008875:Middle Aged; D009107:Mumps / Q000150:complications; D013016:Sound