Finite-element Modelling of the Gerbilmiddle Ear

Abstract

Hearing loss is the third leading chronic disability after arthritis and hypertension, and the most frequent birth defect. Non-invasive diagnoses and middle-ear prostheses are often unsatisfactory, partly because of a lack of understanding of middle-ear mechanics. The focus of this thesis is to develop a 3-D finite-element model to quantify the mechanics of the gerbil middle ear. An MRM dataset with a voxel size of 45 J.Ill1, and an x-ray micro-CT dataset with a voxel size of 5 um, supplemented by histological images, are the basis for 3-D reconstruction and finite-element mesh generation. The eardrum model is based on moiré shape measurements. The material properties of aIl the structures in the model are based on a priori estimates from the literature. The behaviour of the finite-element model in response to a static pressure of 1 Pa is analyzed. Overall, the model demonstrates good agreement with low-frequency experimental data. For example, (1) the ossicular ratio is found to be about 3.5; (2) maximum footplate displacements are about 34.2 nm ± 0.04 nm; (3) the motion of the stapes is predominantly piston-like; (4) the displacement pattern of the eardrum shows two points of maximum displacements, one in the posterior region and one in the anterior region. The results also include a series of sensitivity tests to evaluate the significance of the different parameters in the fmite-element model. Finally, in an attempt to understand how the overall middle-ear mechanics is influenced by the anterior mallear ligament and the posterior incudalligament, results are shown for cutting or stiffening the ligaments.

Cite this paper

@inproceedings{ElkhouriFiniteelementMO, title={Finite-element Modelling of the Gerbilmiddle Ear}, author={Nidal Elkhouri} }