Development of a finite element model for normal and pathological middle ears: Impedance, reflectance, and sweep frequency impedance

A 3D ‘virtual middle ear model' using finite-element modeling techniques was developed to simulate the dynamics of the human middle ear. COMSOLMultiphysics software was used to solve the resulting acoustics-structure interaction problem. The model is validated by comparing numerical results with experimental data measured in the ear canal (EC), on the tympanic membrane (TM), umbo, stapes footplate, and cochlear pressure. The model consists of anatomy from μCT imaging and material parameters from the literature (Cai et al., PLOS One, in review). The EC impedance Zec, reflectance Rec, and the pressure Pec due to a constant displacement Dec (Wada et al., 1998) were calculated for the normal middle ear, with the stapes blocked, and with the stapes disarticulated. The results in this virtual model are consistent with experiments performed in both cadaveric and living ears. The model is used to analyze the sensitivity and specificity of Zec, Rec, and Pec due to variations in the material properties of the middle ear including the TM, ossicles, malleus-incus, and incus-stapes joints, and the footplate. [Work supported in part by grant R01-DC05960 from the NIDCD of NIH and by a Fellowship from the Institute of National Colleges of Technology, Japan.]