Equivalent Circuit Modelling of Bone Conduction Hearing
Master Thesis of Salehi, Masoumeh
The pathways of the sound transmitting from an excitation position (often at the mastoid or forehead of the skull) to the inner ear are not clarified, yet. Five different pathways often suggested as important for bone conducted sound: sound pressure generation in the ear canal, inertial forces on the middle ear ossicles causing a relative motion between the stapes footplate and the cochlear promontory bone, inertial forces acting on the cochlear fluid, alteration of the cochlear space, and sound pressure transmission from the skull interior. In 2015, Stenfelt presented a bone conduction model, which consists of an impedance model representing the inner ear as well as measured transfer functions to consider the different pathways.
The aim of this thesis is to develop a model of bone conduction hearing by means of equivalent circuits only. Therefore, the measured transfer functions as well as underlying assumptions of the wave propagation in Stenfelt’s model are successively replaced by smaller sub-circuits, which are combined with the impedance model of the inner ear. Finally, the model will be used to predict the relation and importance of the bone conduction pathways for different excitation positions.