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Tympanometric Findings in Patients With Enlarged Vestibular Aqueducts
Author(s) -
Sato Eisuke,
Nakashima Tsutomu,
Lilly David J.,
Fausti Stephen A.,
Ueda Hiromi,
Misawa Hayato,
Uchida Yasue,
Furuhashi Atsushi,
Asahi Kiyomitsu,
Naganawa Shinji
Publication year - 2002
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200209000-00021
Subject(s) - tympanometry , medicine , audiology , pure tone audiometry , magnetic resonance imaging , vestibular system , cochlea , sensorineural hearing loss , hearing level , audiometry , hearing loss , radiology
Objectives The purpose of this study was to study systematically some relationships between the resonance frequency of the middle‐ear transmission system and the volume of the endolymphatic duct and sac in patients with an enlarged vestibular aqueduct (EVA). Study Design Prospective study. Methods Thirteen patients (24 ears) with EVA, 17 subjects (29 ears) with normal hearing, and 17 patients (21 ears) with sensorineural hearing loss without EVA served as experimental subjects. Standard pure‐tone audiometry, standard clinical tympanometry (using a 226‐Hz probe tone), and multifrequency tympanometry were performed on each ear. Magnetic resonance imaging was used to determine the area of the cochlear modiolus and the volume of the endolymphatic duct and sac. Results The audiometric configurations for most patients sloped downward from the low to the high frequencies. A significant air‐bone gap was computed at each of these test frequencies. Multifrequency tympanometry yielded resonance frequencies for the patients with EVA that was significantly lower than those measured for the control subjects. In general, for patients with EVA, the resonance frequency of the middle ear system decreased as the volume of the endolymphatic duct and sac increased. This inverse relation was significant (correlation coefficient = −0.483, P = .0157). However, there was no correlation between resonance frequency and the degree of cochlea modiolar deficiency. Conclusions Clinically, our findings suggest that EVA probably should be included in the differential diagnosis for a patient who presents with a moderate to severe mixed hearing loss, a normal tympanogram at 226 Hz, and a resonance frequency that is abnormally low.