Cochlear Implant Electrode Array Design and Speech Understanding

Objective Cochlear implant electrode arrays are categorized based on their design as lateral wall (LW) and perimodiolar (PM) electrode arrays. The objective of this study was to investigate the effect of LW versus PM designs on postoperative speech perception across multiple manufacturers and over long follow-up durations. Design Retrospective cohort study. Setting Single academic medical center. Participants A total of 478 adult cochlear implant recipients, implanted between the years 1992 and 2017. Interventions(s) PM versus LW cochlear implants Main Outcome(s) and Measure(s) Postoperative Consonant-Nucleus-Consonant Word (CNC-w) and Hearing in Noise Test (HINT) scores between 6 months and 5 years. Results Across 478 patients, approximately one-Third received LW (n = 176, 36.8%), whereas 302 patients received a PM array (63.2%). The PM group had higher CNC-w scores from 6 months to 2 years (52 [interquartile range, 38-68] versus 48 [31-62], p = 0.036) and from 2 to 5 years (58 [43-72] versus 48 [33-66], p < 0.001). Multivariable analysis of patient-Averaged scores indicated that the PM group had greater improvement from preoperative scores at all time points after the initial 6 months for both CNC-w (β = 4.4 [95% confidence interval, 0.6-8.3], p = 0.023) and HINT testing (β = 4.5 [95% confidence interval, 0.3-8.7], p = 0.038). Conclusions This study indicates that PM electrode arrays are associated with small increases in postoperative speech perception scores, relative to LW arrays, when assessed across manufacturers, over long time durations, and using multiple outcome instruments. These findings may help guide surgeon selection and patient counseling of cochlear implant arrays.