Perimodiolar Electrode Arrays Are Associated with Superior Hearing Preservation Without Compromising Speech Recognition

Introduction: To compare differences in audiologic outcomes between lateral wall electrodes and perimodiolar electrodes from a single cochlear implant (CI) manufacturer while controlling for preoperative hearing and age in a large cohort.

Methods: A retrospective chart review as used to include adult patients who underwent CI surgery between 2018 and 2025 with Cochlear (Sydney, Australia) 522/622 (lateral wall) or 532/632 (perimodiolar) electrode arrays. Pre- and postimplantation audiometric testing and speech performance at 1-, 3-, 6-, and 12-months were recorded.

Results: One hundred seventy-two patients (190 ears) were included, of which 66 (34.7%) and 124 (65.3%) ears were implanted with lateral wall and perimodiolar electrode arrays, respectively. 47 (24.7%) ears had low-frequency hearing preoperatively. Hearing preservation was significantly better after implantation with a perimodiolar electrode than with a lateral wall electrode after controlling for age, race, sex, and preoperative low-frequency pure tone thresholds (p = 0.036). CNC and AzBio scores were not significantly different between electrode arrays (p = 0.61 and p = 0.72, respectively).

Conclusions: In our study cohort, perimodiolar electrodes were associated with improved preservation of low-frequency hearing compared to lateral wall electrodes, after controlling for age and preoperative hearing. However, patients had similar CNC and AzBio outcomes regardless of the type of electrode array.