Wideband Absorbance Pattern and its Diagnostic Value in Adults with Middle Ear Effusions and Tympanic Membrane Perforation

Abstract

BACKGROUND: Middle ear effusion (MEE) and tympanic membrane perforation (TMP) are difficult to distinguish using existing immittance techniques, necessitating the use of a separate test battery. Wideband absorbance (WBA) tympanometry is a new enhanced technique, and studies have shown a reliable WBA pattern to identify middle ear disorders. Thus, the study was performed to determine the WBA across the frequencies in ears with MEE, TMP, and compared with normal hearing individuals. METHODS: A total of 109 ears with TMP and 122 ears with MEE in the age range of 22-50 years were compared with 150 normal hearing ears. Otoscopic examination, middle ear fluid monitor, pure tone audiometry, and immittance measurements were performed to categorize the subject ears into groups. The absorbance levels at peak and ambient pressure across one-third octave frequencies in each group were statistically evaluated at α=0.05. RESULTS: Wideband absorbance for the normal ear group was lowest at low (3000 Hz) and highest at midfrequency regions (800-3000 Hz). The MEE group had significantly lower WBA at all frequencies, and TMP group showed reduced WBA at low and mid-frequencies (<2500 Hz). Wideband absorbance at peak pressure was slightly higher than ambient pressure in all the groups. Receiver operating characteristic analysis demonstrated a high diagnostic value in the mid-frequency region for both the TMP and MEE groups. CONCLUSION: Wideband absorbance provides high reliability in discriminating between MEE and TMP and has a unique WBA pattern. Thus, WBA can be a useful diagnostic tool for the identification of middle ear disorders.