Differences of Basilar Membrane Responses Due to Spiral Geometry Identified from Passive Cochlea Numerical Models

In this study, the dynamics responses of basilar membrane in an inner ear were investigated in order to identify the differences between spiral and uncoiled cochleae using passive finite element models. To compare the dynamics responses of the basilar membrane, an uncoiled cochlea model was developed considering the fluid-structure interactions and the transverse orthotropic material properties of basilar membrane. A spiral cochlea model was also constructed by transforming only the nodal coordinates of the uncoiled model into spiral geometry. Then, the dynamic characteristics of two cochlear models were compared in frequency domain. Compared vibrational components of basilar membrane in longitudinal and radial directions in the spiral cochlea model showed large differences compared to those of the uncoiled one. It was discussed whether these differences have influences on the hearing capability in very low and high frequency ranges.