Energy Efficiency in Cochlear Implants: The Impact of Electrode Design and Activation Timing

To evaluate the effect of electrode type and time of activation on battery performance in cochlear implant (CI) users.

A retrospective cross-sectional study was conducted on 39 CI recipients (57 ears) implanted between 2019 and 2023 at a tertiary center. Participants were grouped based on electrode type, Slim Modiolar/Perimodiolar (PM) vs. Slim Straight/Lateral Wall (LW) and activation timing, early (1-5 days) vs. late (3-6 weeks). Battery performance (standard, standard rechargeable, compact rechargeable) was assessed at five time points at: activation, 1,3,6, and 12 months post-activation. Data were analyzed using Mann-Whitney U tests.

Battery life declined progressively over the 12-month follow-up period. On average, standard batteries declined by approximately 16 hours (∼35%), standard rechargeable batteries by 7-9 hours (∼30-35%), and compact rechargeable batteries by 3-4 hours (∼30-35%). This trend was consistent across activation groups and electrode types, although absolute values varied slightly depending on configuration. Standard batteries consistently outperformed rechargeable options. Early activation was associated with significantly higher energy consumption at 1 month post-activation for standard batteries (median: 35 vs. 45 hours; p = 0.032), with no sustained differences thereafter. In the long term, PM electrodes demonstrated significantly longer battery life than LW electrodes at 12 months for standard (p = 0.016), standard rechargeable (p = 0.005*), and compact rechargeable (p = 0.001*) batteries.

Battery consumption was mainly influenced by electrode design, with PM electrode showing superior energy efficiency. Although early activation increases short-term battery use, it does not affect long-term consumption. These findings support PM electrode selection to enhance device efficiency and users experience.