Paul Wong, Shefin George, Phillip Tran, Andrian Sue, Paul Carter, and Qing Li, The University of Sydney, The Bionics Institute, Cochlear Limited, Australia
Electroanatomical models are a promising means for furthering our understanding of the electrophysiological response to electrical stimulation. In cochlear implant research, existing models of the inner ear have yielded new insights for further improving implant designs. However, the level of anatomical detail is typically lower than ideal due to imaging limitations, leading to the omission of fine structures such as Reissner’s membrane and the cochlear vasculature, which may play an important role in determining current flow.
This paper introduces a new finite element model that was developed from high resolution scanning thin-sheet laser imaging microscopy (sTSLIM) images of the guinea pig cochlea. The model was validated against independently obtained in vivo voltage tomography data from the Bionics Institute in Melbourne, Australia. Spatial visualisations of the current pathways and neural response were used to illustrate the underlying physics, providing an intuitive way to evaluate the appropriateness of existing assumptions on material properties and boundary conditions. The model demonstrated a strong correlation with the in vivo data, building confidence for using the model in future investigations.
Keywords: Boundary conditions, cochlear implants, electrical stimulation, finite element analysis, image segmentation.