Wideband Absorbance Measurements: Norms and Middle Ear Disorders / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: To evaluate the usefulness of wideband tympanometry in predicting middle ear disorders by comparing the absorbance measurements of the disorder and the norm. SUBJECTS AND METHOD: Wideband tympanometry, pure tone audiometry, and endoscopic examination were performed on 284 ears of 190 subjects. Wideband absorbance (WBA) was measured from normal ears (adults 128 ears, children 32 ears), disorders of middle ear included effusion (adults 24 ears, children 21 ears), tympanic membrane (TM) retraction (adults 26 ears, children 6 ears) and perforation (47 adult ears). RESULTS: The normative data of WBA were similar to previous reports from other countries. WBA of the 17-29 age group showed higher values than other age groups at 1600-3150 Hz. Men had higher absorbance at low frequencies whereas women had higher absorbance at high frequencies. There was a significant gender difference at 4000 Hz. Adults showed higher absorbance at 1000, 1250, and 1600 Hz and lower absorbance at 2500, 3150, and 4000 Hz than children did at those respective frequencies. Compared to the normal group, WBA was decreased at all frequencies by more than 500 Hz in ears with middle ear effusion and at most frequencies by less than 2000 Hz in ear with TM retraction. TM perforation showed higher absorbance in low frequencies; the absorbance decreased as the size of perforation increased. CONCLUSION: The present study established normative WBA data and the results showed comparable statistics to former studies in age and gender difference. WBA provided a high reliability in discrimination of middle ear effusion and TM retraction. WBA is a simple, non-invasive and useful diagnostic tool for middle ear disease.