| Cochlear implants help provide a sense of hearing for those who suffer a severe to profound hearing loss and receive only minimal benefit from hearing aids. The cochlea, however, poses a challenging obstacle, because it is the size of a pea and is embedded in the petrous temporal bone—the hardest bone in the body. Models of the implanted cochlea enable designers and clinicians to figuratively peer directly into the working cochlea. This work describes a dynamic model of the guinea pig cochlea, which was used to simulate intracochlear electric field distributions and the neural responses they create. To create a composite cochlea with anatomically true generalized dimensions, orthogonal-plane fluorescence optical sectioning (OPFOS) images from eight guinea pig cochleae were analyzed and measured. A lumped-element approach enabled more pragmatic design adaptability and faster result calculation than other piecewise element methods. The usual pitfalls of reduced precision associated with the lumped-element method have been addressed by more extensive and resolute element definition. Electric fields and neural responses were calculated for different electrode insertion depths, transverse scalar electrode positions, carrier diameters, stimulation configurations, pulse widths, and pulse rates. A paradigm of stimulation via the scala vestibuli for cases of tympani ossification was also analyzed. |
