A Model for Evaluating Electrode Impedance Stabilization in Pediatric Cochlear Implant Recipients.

Abstract

Electrode impedance (EI) is a key biomarker in cochlear implantation, reflecting tissue reactions and influencing stimulation efficiency. This study investigates a patient-specific model for determining impedance stabilization onset. In this study, impedance stabilization was defined as a less than 10% difference in impedance values between two consecutive fitting sessions conducted at least 1 month apart. A time-to-event model was used to identify the stabilization onset along electrode regions and overall impedance. A comparison of stabilization times was also performed between classical activation (1-month post-surgery, CA) and early activation (1-day post-surgery, EA). A cohort of 395 cochleae (225 with CA and 170 with EA) was analyzed. The EA group demonstrated significantly shorter overall impedance stabilization onset (2.8 months) than the CA group (5.0 months). Stabilization onset was also faster for EA group across apical, middle, and basal electrodes (3.1, 3.0, and 3.2 months) compared to CA (5.4, 5.0, and 4.7 months). At stabilization onset, impedance values were lower, though not statistically significant, along the electrode regions in the EA group (7.98, 5.43, 5.84 kΩ) than in CA (8.25, 5.65, 6.07 kΩ). The difference in EI between the stabilization onset and the last recorded time after the 5-year follow-up was minimal in both groups, showing a long-term stabilization. The proposed model effectively evaluated impedance stabilization onset timing and values. Stabilization patterns varied across electrode regions and overall impedance. Early activation showed significantly faster stabilization onset than classical activation. Further research is needed to explore factors affecting long-term stabilization outcomes. Level 3.