Analysis of Tympanometric Attributes in Middle Ear Diseases and in Postoperative Middle Ear Surgeries - A Prospective Study at a Tertiary Hospital in Hyderabad, Telangana

Abstract

BACKGROUND Tympanometry as a definitive test protocol in the diagnosis of middle-ear disease and function remains still a tentative one. Primarily this is the result of cost effectiveness and concerns over referral to an audiology unit. It was also found to be due to the concerns over variability in test protocols and its influence on demographic and environmental factors. The present study was done to simplify the understanding of the different test variables of tympanometry. METHODS The clinical study was conducted in the Department of ENT, Deccan College of Medical Sciences and Princess Esra Hospital, Hyderabad. Out of 134 patients registered with loss of hearing, 68 patients were grouped as preoperative group (136 ears) and 66 patients as postoperative group (132 ears). The patients in both groups were registered at different times and they were not the same. Audiology equipment used was impedance audiometers (Siemens SD 30, interacoustics AT 235 H); portable tympanometer (Welch-Allyn). Preliminary pure tone audiometry was also done to supplement the diagnosis. The test results were reported as: conductive, sensorineural, and mixed hearing loss. The results were reported based on the variables/criteria: admittance, tympanometric peak pressure (TPP), peak amplitude (Ya peak) and the volume of the ear canal. RESULTS There were 39 males (57.35 %) and 29 females (42.64 %) in the preoperative group. There were 41 males (62.12 %) and 25 females (37.87 %) in the postoperative group. Middle ear diseases showing conductive deafness were grouped as four types: a) middle ear effusion (35 patients); b) Eustachian tube dysfunction (31 patients); c) Ossicular chain adhesions (38 patients) d) tympanic membrane perforations and tympanosclerosis (28 patients) and e) otosclerosis (02 patients). CONCLUSIONS Using tympanometric attributes such as admittance, tympanometric peak pressure, peak amplitude (Ya peak) and the volume of the ear canal, it was possible to make accurate diagnosis of middle ear diseases and their exact pathology or make a differential diagnosis. The attributes used gave much accurate measure of the mechano-acoustics than the preset values used regularly by many centres. KEY WORDS Impedance Audiometry (Tympanometry), Middle Ear Diseases, Compliance, Peak Pressure and Tympanometric Peak Pressure (TPP)