Multifrequency immittancemetry in experimentally induced stapes, round window and cochlear lesions.
Audiol Neurotol. 2007-01-01; 12(2): 85-100
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1. Audiol Neurootol. 2007;12(2):85-100. Epub 2006 Dec 6.
Multifrequency immittancemetry in experimentally induced stapes, round window and
Darrouzet V(1), Dulon D, Franco-Vidal V.
(1)Otolaryngology and Skull Base Surgery Department, University of Bordeaux 2
Victor Ségalen, Bordeaux, France.
OBJECTIVES: To establish that admittance (Y) and susceptance (B) conductance (G)
tympanograms at 2 kHz can reflect the status of the annular ligament and the
METHODS: Seven experiments were set up in 22 guinea pigs: ventilation of the
bulla, blockage of the stapes and round window membrane (RWM), fistula, fluid
removal from the cochlea, injection of saline in the scala tympani and acoustic
trauma. Resonance frequency, Y, B and G at 2 kHz and curve shapes were analyzed
before and after lesions.
RESULTS: A supplementary peak was observed in Y/G tympanograms in all RWM
fistulas and in some cases of acoustic trauma; injection of saline into the scala
tympani induced constant, immediate and reproducible changes; RWM and stapes
blockages induced foreseeable peaking at 2 kHz; fluid removal from the cochlea
induced multiple peak curves.
CONCLUSION: Experimentally induced modifications at the AL result in noticeable,
constant and reproducible changes in tympanogram curves at 2 kHz and seem to
reflect inner ear pressure.
Copyright 2007 S. Karger AG, Basel.
PMID: 17264472 [Indexed for MEDLINE]