Effect of middle-ear pathology on high-frequency ear-canal reflectance measurements in the frequency and time domains

Wideband immittance and reflectance have not been well described at frequencies above 6-8 kHz, and past analyses of these measurements have focused on the responses to stimulus frequencies below 3-4...kHz, while ignoring high-frequency or time-domain information. This work uses a novel approach to measure reflectance that utilizes high-frequency signals and analyzes reflectance in both the frequency and the time domains. Experiments were performed with fresh normal human temporal bones before and after simulating various middle-ear pathologies. In addition to experimental data, novel model analyses were used to obtain fitted parameter values of middle-ear elements that vary systematically due to simulations and thus may have diagnostic implications. Our results show that high-frequency measurements improve temporal resolution of reflectance measurements, and this data combined with novel modeling techniques provides separation of three major conductive pathologies.