Is Carhart notch an accurate predictor of otitis media with effusion?

Abstract

Background In the era of pediatric otolaryngology, a number of different methods have been used for the diagnosis of otitis media with effusion (OME). Although there are divers articles within the filed of assessment of the accuracy of diagnostic methods of OME, surprisingly there are very few data published and a small number of researches explaining the accuracy of Carhart notch (CN) for diagnosis of OME cases and comparing the CN with abnormal tympanic membrane findings in binocular microtympanoscopy. Methods Audiometric parameters studied in 89 children (178 ears) suffering from chronic otitis media with effusion. Significant CN was defined as a minimum depression of 10 dB in comparison of the rest of thresholds, at any frequency from 500 to 4000 Hz. Intra-operative microscopic otoscopic findings and the type of middle ear fluid were documented in a specially formatted questionnaire. Results The incidence of CN was 44.94% (80 ears) and that of significant CN was 25.28% (45 ears). The correlation between abnormal tympanic membrane findings and significant CN was significant and the association between CN and middle ear effusion (MEE) was not statistically significant. Conclusions Significant CN is a sensitive diagnostic tool for detection of MEE but not specific. The diagnosis of OME in children requires a combinational diagnostic methods including tympanometry and audiometric variables especially CN.