Influence of Tympanic Membrane Perforation on Hearing Loss

Ear is the most pressure sensitive organ of the body and is susceptible for rupture with altered pressure. Tympanic membrane (TM) perforation reduces the total ratio of surface area, allowing the sound waves to directly pass through the middle ear. However, implications of the tympanic membrane perforation on sound transmission in the middle ear is not well characterised. The study was undertaken to correlate size and site of TM perforation with the hearing loss. Participants of the study involved both the sexes with dry ear. Individuals below 15years of age, active ear discharge, tympanosclerosis, ossicular chain fixation, presence of mixed and sensori-neural component were excluded from the study. A total of 50 patients within 15 to 50years with tympanic membrane perforation were recruited for the study. The participants were classified in 5 groups based on the size and site of tympanic membrane perforation. Pure tone Audiometry was performed on the participants who complained of ear discharge 5-6days before testing. Three frequency (500Hz, 1000Hz and 2000Hz) air conduction thresholds were used to determine the hearing level. One-Way ANOVA test and Duncan post hoc test was applied to obtain a statistically significant difference with p>0.05 to obtain a significant difference between the groups and hearing loss across 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz frequencies using SPSS software version 16. Results revealed that the degree of hearing loss increases as the size of TM perforation increases. Clinically, prediction of the hearing loss would be easy based on the site and size of TM perforation.