Objective: This study was performed to reevaluate the diagnostic significance of clinically well-accepted audiological tests in indicating endolymphatic hydrops (EH) in Menière's disease (MD).
Study design: Retrospective case review.
Settings: Hospital.
Patients: Fifty patients (52 affected ears) diagnosed with MD were enrolled.
Intervention: Diagnostic.
Main outcome measure: To analyze the correlations between endolymphatic hydrops and results of audiological test including the pure-tone audiometry threshold, suprathreshold function tests, electrocochleogram, and glycerol test.
Results: Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging demonstrated EH in either the vestibule or cochlea to various degrees in all of the MD patients, 24 hours after intratympanic gadolinium chelate injection. Both vestibular and cochlear EH were significantly correlated with PTA threshold. However, EH was not associated with alternate binaural loudness balance or the tone decay test, although a correlation was observed with the short-increment sensitivity index. There was also a correlation between vestibular EH, but not cochlear EH, and the negative summating potential/action potential (-SP/AP) ratio. Neither vestibular EH nor cochlear EH was correlated with the glycerol test results. In addition, the frequency of vertigo attacks, the existence of tinnitus, and aural fullness did not correlate with EH.
Conclusions: Disrupted ionic homeostasis in the inner ear, but not the EH, may contribute to changes in the -SP/AP ratio. The relevance of glycerol test in identifying EH through detection of hearing changes needs further investigation in the future.