The long-term objective of this project is to identify the fundamental mechanisms that limit the benefit a patient derives from cochlear implantation. Better treatment of profound hearing loss with a cochlear implant (improved candidacy criteria, patient prognostication, and implant designs) will depend crucially on an understanding of both the factors mediating performance, and how they can be addressed. Our first step toward this objective is to use quantitative modeling to examine the impact of different pathologies seen in the histologically-processed temporal bones harvested from users of multichannel cochlear implants. Specifically, we will use the serially-sectioned temporal bones of two subjects to build a patient-specific computer model for each that represents their unique anatomy. These models will make it possible to (1) test the model's predictions of behavioral threshold against results collected during the patient's life and (2) investigate the relative impact of specific anatomical properties on those predictions. To the extent that these patient-specific models explain features of the subjects' measured performance, they are a first step in eventually understanding the features that determine the patient benefit. [unreadable] [unreadable]