Parameter study on a finite element model of the middle ear.

Models of the middle ear basing on the finite element method (FEM) have contributed to a better understanding of the function of its different components. The geometry, the choice of boundary conditions and material properties have a crucial influence on the model. The influence of individual parameters was investigated. Based on a magnetic resonance imaging data set, a finite element model (FEm) of the middle ear was established. The transfer function (TF) at a sound pressure level of 90 dB and a frequency range from 100 Hz to 10 kHz was determined. Altogether, 24 parameters were varied individually and the influence on the TF was investigated. The parameter study was based on varying the stiffness and damping of each material as well as on anatomic variations, such as thickness and anisotropy of the tympanic membrane and sliding within the joints. It could be shown that each parameter had influence over the entire or sections of the frequency range in different magnitudes. A chart was derived to show the influence of each parameter depending on the frequency. The results allow improved distinguishing between parameters being relevant for a FEM simulation of the middle ear and those that can be neglected. This could contribute to further improvement of FEms of the middle ear.