Introduction Chronic otitis media (COM) is an inflammation of part or all of the mucoperiosteal lining of middle ear cleft. The disease has two types; mucosal and squamous (cholesteatoma). Most perforations of pars tensa are central indicative of mucosal disease. All attic disease and marginal perforations are indicative of squamous disease. The typical feature of squamous disease is the presence of a cholesteatoma (Keratinizing squamous epithelium) in the middle ear cleft.1 The bony involvement by the disease may give rise to granulation or polyp. Round window membrane is the only soft tissue barrier separating the middle ear from the inner ear. This semipermeable membrane appears to be the main portal for the passage of noxious substances …show more content…
Table IV shows mean bone conduction hearing threshold at each frequency in the diseased ear in relation to the duration of pathology. It shows increased hearing loss with increasing duration of pathology and this relation was statistically significant (p > 0.05). There is 15dB or greater bone conduction hearing loss at one frequency or more in 42.8% of the patients involved in the study and there is 15dB or greater hearing loss at two frequencies or more in 21.4% of the patients. Table V shows mean bone conduction hearing thresholds at each frequency in relation to the type of pathology. There is increase in bone conduction hearing threshold with granulation tissue, polyp, and cholesteatoma. This relation was statistically significant (p < 0.01). The site and size of the perforation have no significant effect on bone conduction of diseased ear. Table III. Frequency specific bone conduction threshold in dB at each frequency in normal and diseased ear Frequency (Hz) Mean (dB) Median (dB) Range (dB) Normal ear 500 1000 2000 4000 5.85± 0.14 7.42± 0.12 9.50± 0.1 10.71± 0.09 …show more content…
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