Influence of the model parameters for the finite element simulation of bone conduction in the human head

Abstract

Bone conduction (BC) describes the transmission of vibrations via osseous, cartilage, and soft tissue pathways that contribute to the hearing sensation. It is important, e.g., in the context of BC hearing aids as well as for the occlusion effect and one’s own voice perception when using hearing protection or hearing devices. Finite element (FE) simulations of BC allow to overcome practical and ethical limitations of measurements with real heads and help to gain insights into underlying mechanisms. However, FE models inevitably require substantial simplifications due to the assignment and definition of volumetric domains and corresponding materials. Additionally, the material parameters are often only known within certain ranges. In this presentation, an overview on FE models of human heads used for BC research is given, and similarities and differences are discussed. The influence of the FE-inherent simplifications and the challenges in determining the model parameters are illustrated by varying the geometry and the material properties of a simple ellipsoidal model. The variability of the model predictions is compared to simulation results obtained with more realistic geometries and to the inter-subject variability observed in measurements with real human heads reported in the literature.