Image-Guided Cochlear Implant Programming (IGCIP)

Over 500,000 individuals worldwide have received cochlear implants (CIs). While postoperative speech understanding is significantly better than preoperative levels, even the best performers complain that the fidelity of natural hearing is not reproduced, and a significant minority achieve poor outcomes despite normally functioning equipment. Poor neural survival is suspected in many patients achieving below-average outcomes; however, this cannot be confirmed as post-mortem histopathology is required to accurately document spiral ganglion cell count. In recent years attention has focused on the intracochlear location of CI electrodes as a potentially controllable factor affecting CI function. Technological improvements in imaging with CT scanning have made it possible to determine the scalar location of an electrode array and whether it has crossed from one scala to another. While working on techniques to assess postoperative electrode location, our research group postulated that benefit may arise by altering programming strategies based upon the final, post-operative location of the electrode array. Towards this end, we have developed and validated techniques allowing us to predict, with a high level of accuracy, the distance from the frequency-mapped modiolus to each individual electrode. Using these electrode distance versus frequency curves, we have implemented a relatively straight forward programming strategy where we deactivate electrodes to minimize electrode interaction. Using post-operative CT scanning to determine the geometric relationship between the electrode array and the modiolus, we deactivated, on average, 1/3 of active electrodes per patient. Within this initial cohort, we have demonstrated statistically significant improvement for audiological metrics of speech understanding, spectral and temporal resolution, and quality of life. We will describe auditory outcomes following implementation of IGCIP in over 200 adult and 36 pediatric CI recipients including effects of postoperative electrode location, electrode-to-modiolus distances, and signal coding strategies on postoperative outcomes. Clinical (surgical and audiological) and research applications of IGCIP technology will be discussed.