Assessment of Degree of Hearing Loss Depending on Site and Size of Tympanic Membrane Perforation in Inactive Mucosal Variety of Chronic Otitis Media

Abstract

BACKGROUND Tympanic membrane perforation is one of the most common causes of hearing impairment. We have compared the audiological results depending on the site and size of tympanic membrane perforation. METHODS This is a prospective study of 120 patients who attended ENT OPD of our department during the period of April 2012 to March 2013 with inactive mucosal variety of chronic otitis media. All 120 patients had undergone video otoendoscopic evaluation and pure tone audiometry to evaluate the size and site of perforation and correlate it with AB gap and AC threshold. RESULTS In our study, pinpoint perforation has an average of 28 dB (SD-3.79) AC threshold and 13.94 Db (SD-3.43) AB gap while subtotal perforation has 47.36 dB AC thresholds and 34.64 dB AB gap. Small, medium and large size perforations have an average of 35.25 dB, 39.93 dB, 44.77 dB AC threshold and 20.79 dB, 26.13 dB and 30.31 dB AB gap respectively. The results are statistically significant (p<0.001). Overall, central type of tympanic membrane perforation has highest (Mean AC threshold 43.26 dB and AB gap 29.28 dB) hearing loss compared to single quadrant perforation. Posterior perforation has mean AC threshold of 36 dB, AB gap 21.35 dB while anterior and inferior perforations have mean AC threshold 27.50 dB and 28.86 dB and mean AB gap 14 dB and 15.5 dB respectively. CONCLUSIONS As the size of perforation increases, the hearing loss increases, and it is also clear that posterior perforation has more hearing loss compared to anterior perforation. The results are statistically significant.