Determinants of Cochlear Dysfunction in Chronic Otitis Media: Mucosal Disease.

The nature of association between chronic otitis media (COM)-mucosal disease and sensorineural hearing loss is controversial. Identifying the risk factors which influence the bone conduction threshold in these patients can help the clinician in counselling the patients for surgery at the earliest to achieve optimum hearing outcomes. The present study was undertaken to determine the association between COM-mucosal disease and cochlear dysfunction. The study also aimed at identifying the determinants and their influence on the bone conduction thresholds of the diseased ear. In this study, 72 patients with unilateral chronic otitis media-mucosal disease were enrolled consecutively. All patients were enquired in detail about their presenting ear symptoms. All the patients underwent a pure tone audiogram in a sound treated room. Patients were categorised into two groups according to the presence of conductive hearing loss only or with a sensorineural component. The bone conduction thresholds were calculated and compared for frequencies at 0.5, 1, 2 and 4 kHz. The average hearing threshold for air conduction and bone conduction were calculated across 0.5, 1 and 2 kHz. Bone conduction threshold more than 20 decibels (dB) in any of the frequencies were considered significant and indicative of having sensorineural hearing loss component. The contralateral healthy ear served as control to cancel out the confounding factors such as presbyacusis, noise induced hearing loss, congenital hearing loss, etc. Multivariate linear regression models were used to evaluate the relationships between bone conduction thresholds and chronic otitis media-mucosal disease. In the present study, 18.05% of participants had a sensorineural component. The difference between the bone conduction threshold in the diseased ear and normal ear ranged from 5.41 dB at 0.5 kHz to 3.77 dB at 4 kHz (