A Unique Perspective: Intrapatient Comparison of Perimodiolar and Lateral Wall Cochlear Implant Electrodes

OBJECTIVE: The debate regarding the optimal cochlear implant (CI) electrode array-perimodiolar (PM) versus lateral wall (LW)-has intensified with evolving technology. Comparing electrode designs is challenging due to variability in patient characteristics. This study compares PM versus LW electrodes placed in opposite ears of the same patients. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Individuals undergoing bilateral cochlear implantation with a LW electrode in one ear and a PM in the other from 2003 to 2023. INTERVENTION: Bilateral cochlear implantation with each electrode type. MAIN OUTCOME MEASURES: Demographics and audiologic data (4-frequency pure tone average (PTA), consonant-nucleus-consonant (CNC) scores, and AzBio scores in quiet and noise). Outcomes were compared using Wilcoxon Signed Ranks Test with SPSS version 27. RESULTS: Thirty-two patients met inclusion criteria. Median age at PM and LW implantation was 64.5 (Q1-Q3: 46.8 to 71.9) and 69.6 (50.6 to 76.3) years, respectively. CNC scores were significantly higher in PM arrays: 66% (51 to 71) vs. 42% (26 to 70), P =0.008. AzBio scores in quiet (75% vs. 67%, P =0.082) and noise (59% vs. 63%, P =1.000) showed no significant differences. Battery life was longer in the PM group (33.5 vs. 30 hours), though not statistically significant ( P =0.819). CONCLUSION: PM arrays offer improved CNC word understanding when compared with LW arrays, but do not offer a significant improvement in battery life or AzBio scores. To our knowledge, this is the first study to compare these outcomes using each patient as their own control, thereby controlling for the majority of patient factors that could influence performance.