The influence of otitis media with effusion on middle-ear impedance estimated from wideband acoustic immittance measurements

The goal of this work was to estimate the middle-ear input impedance (Z me) from wideband acoustic immittance (WAI) measures and determine whether Z me improves the clinical utility of WAI. The data used in this study were from a previously reported set of WAI measurements in ears with otitis media with effusion [OME; Merchant, Al-Salim, Tempero, Fitzpatrick, and Neely (2021). Ear Hear., published online]. Ears with OME were grouped based on effusion volume, which was confirmed during tube surgery. Z me was estimated from the measured ear-canal impedance. An electrical-analog model of ear-canal acoustics and middle-ear mechanics was used to model the ear canal and Z me. The model results fit the measured responses well for all conditions. A regression approach was used to classify the responses of different variable types to effusion volume groups and determine the specificity and sensitivity of the binary classifications. The Z me magnitude increased with increasing effusion volume. The area under the receiver operating characteristic curve (AUC) was compared for binary decisions of the OME categories. The Z me estimate resulted in a clinically meaningful improvement in the AUC for distinguishing healthy ears from ears with OME. Overall, these results suggest that Z me estimation may provide useful information of potential clinical value to improve the diagnostic utility of WAI measurements for OME.