Imaging evaluation of electrode placement and effect on electrode discrimination on different cochlear implant electrode arrays

Abstract

Objective

The aim of the present study is to evaluate the effect of electrode discrimination based on electrode to modiolus distance in different cochlear implant models, using image information to estimate the outcomes after an implantation on electrode discrimination

Methods

A descriptive prospective randomized study performed during 16 months. A psychoacoustic platform was used to evaluate patients' electrode discrimination capabilities of patients. For the acquisition of the images, a cone beam computed tomography was used to assess postcochlear implantation of electrodes' position. We considered two other new measurements: the intracochlear position index, which indicates how far is the electrode from the modiolar wall, and the homogeneity factor (HF), which provides us with information about the distance between the electrodes and the modiolus

Results

21 postlingually deaf adults showing different CI models [CI522 (n = 7), CI512 (n = 7), and CI532 (n = 7)] that corresponded to the lateral and perimodiolar array electrodes. The average success rate of the CI522 group was 47%, of the CI512 group was 48%, and of the CI532 group was 77%. There is statistically significant difference between groups CI532–CI522 (p = 0.0033) and CI532–CI512 (p = 0.0027)

Conclusion

The Nucleus CI532 offers a better perimodiolar placement. HF and IPI measurements provide information about the electrodes location inside the cochlea, being related to electrode discrimination.

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