Prevalence and clinical significance of spontaneous low-frequency air-bone gaps in Meniere's disease

Abstract

OBJECTIVES: The prevalence and clinical significance of spontaneous low-frequency air-bone gaps (LFABGs) in Ménière's disease were investigated. STUDY DESIGN: A retrospective study. SETTINGS: Tertiary referral center. PATIENTS: Three hundred thirty-seven patients with definite Ménière's disease. MAIN OUTCOME MEASURES: The prevalence of LFABG in this population was calculated, and the following parameters were analyzed: 1) changes in hearing thresholds after the resolution of LFABG; 2) correlation between LFABG and electrocochleography (ECoG) results; 3) changes in the number of vertigo spells after the resolution of LFABG; 4) correlation between LFABG and canal paresis (CP) values in caloric testing; and 5) the difference in the prognoses of patients with and without LFABG. RESULTS: The prevalence of LFABG was 13.9%. Patients' hearing thresholds were significantly decreased after the resolution of LFABG (from 49.4 ± 16.8 to 38.3 ± 19.3, p = 0.044), whereas the summating potential and action potential ratio in ECoG tended to increase as LFABG increased (R = 0.09, p = 0.03). The mean number of vertigo spells was significantly reduced after the resolution of LFABG (from 2.9 to 0.5, p < 0.0001), but CP did not correlate with LFABG. The prognosis was not different for patients with and without LFABG. CONCLUSION: The number of vertigo spells and hearing thresholds were significantly higher during the period of LFABG development. Although the prognostic importance of LFABG was not significant, it likely reflects the aggravation of the endolymphatic hydrops in the cochlear and vestibular compartments and may be useful for evaluating and treating patients with Ménière's disease.