Preserving Wideband Tympanometry Information With Artifact Mitigation

Abstract

Objective: Absorbance measured using wideband tympanometry (WBT) has been shown to be sensitive to changes in middle and inner ear mechanics, with potential to diagnose various mechanical ear pathologies. However, artifacts in absorbance due to measurement noise can obscure information related to pathologies and increase intermeasurement variability. Published reports frequently present absorbance that has undergone smoothing to minimize artifact; however, smoothing changes the true absorbance and can destroy important narrow-band characteristics such as peaks and notches at different frequencies. Because these characteristics can be unique to specific pathologies, preserving them is important for diagnostic purposes. Here, we identify the cause of artifacts in absorbance and develop a technique to mitigate artifacts while preserving the underlying WBT information. Design: A newly developed Research Platform for the Interacoustics Titan device allowed us to study raw microphone recordings and corresponding absorbances obtained by WBT measurements. We investigated WBT measurements from normal hearing ears and ears with middle and inner ear pathologies for the presence of artifact and noise. Furthermore, it was used to develop an artifact mitigation procedure and to evaluate its effectiveness in mitigating artifacts without distorting the true WBT information. Results: We observed various types of noise that can plague WBT measurements and that contribute to artifacts in computed absorbances, particularly intermittent low-frequency noise. We developed an artifact mitigation procedure that incorporates a high-pass filter and a Tukey window. This artifact mitigation resolved the artifacts from low-frequency noise while preserving characteristics in absorbance in both normal hearing ears and ears with pathology. Furthermore, the artifact mitigation reduced intermeasurement variability. Conclusions: Unlike smoothing algorithms used in the past, our artifact mitigation specifically removes artifacts caused by noise. It does not change frequency response characteristics, such as narrow-band peaks and notches in absorbance at different frequencies that can be important for diagnosis. Also, by reducing intermeasurement variability, the artifact mitigation can improve the test–retest reliability of these measurements.

The Rise and Fall of Aural Acoustic Immittance Assessment Tools

“…Researchers are developing methods to refine WBA measurements, mitigate sources of variability, and gather larger data sets to better describe measurements from different middle ear pathologies. [47][48][49] These efforts are instrumental for the determination and characterization of etiology-specific features in WBA measurements to be used diagnostically. In the future, trained clinicians will be able to examine WAI outcomes and qualitatively determine whether WBA has features that indicate specific pathologies (e.g., otitis media vs. otosclerosis vs. cholesteatoma).…”

Characteristics of large vestibular aqueduct syndrome in wideband acoustic immittance

“…The absorbance in the frequency range < 2,500 Hz was higher in the LVAS group than in the control group, which was consistent with the frequency superposition range of the maximum absorbance. The absorbance in the frequency range < 1,100 Hz was significantly different between the two groups, which was the major frequency range where the maximum absorbance increased ( Aithal et al, 2017 ; Demir et al, 2020 ; Eberhard et al, 2022b ; Meng et al, 2022 ; Tanno et al, 2022 ). At the same time, the absorbance in the frequency range > 3,000 Hz in the frequency-absorbance curve at peak pressure was lower in the LVAS group than in the control group.…”