Tissue Growth Characterization for Cochlear Implant Users

It is known from post-mortem histological studies that a significant portion of individuals who undergo cochlear implantation (CI) have scar tissue form around the implanted electrode array over time. This scar tissue affects the electrical performance of the cochlear implant, affecting how the implant stimulates the auditory nerve. It is possible that if this scar tissue was detected, the implant programming could be adjusted to account for the changing tissue properties. As part of another study, a computational modeling approach for patient-customized simulation of cochlear implant stimulation is being developed. The simulation approach uses as input CT images and electrophysiological measurements from the cochlear implant device to simulate stimulation by the cochlear implant. These computational simulation models also provide a way to estimate tissue growth around the array. Tissue growth estimates are optimized in the computational model so that electrophysiological metrics simulated by the model match measurements acquired from the patient's implant. In this study, the aim is to collect data necessary to validate these model predictions. While the existence of tissue growth around the implanted array is not typically known for most patients, a subset of cochlear implant recipients need to undergo revision surgery when a device failure or poor placement is suspected. For these individuals, the existence of tissue growth around the array in the base of the cochlea can be visualized in the operating room by the surgeon. Individuals will be recruited who are undergoing CI revision surgery at Vanderbilt University Medical Center to participate in this study. In surgery, the presence of scar tissue growth will be evaluated by visual confirmation by the surgeon.