Long-Term Impedance Trends Over 10 Years Following Cochlear Implantation: A Retrospective Comparative Analysis
- 1Ear Research Center Dresden, Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
Abstract
Importance: Impedance monitoring is a critical component of cochlear implant (CI) surgery, yet the lack of comprehensive longitudinal data limits the development of evidence-based postoperative monitoring guidelines, potentially compromising patient outcomes.
Objective: To track impedance trends over 10 years post-implantation, evaluate the effects of electrode design on impedance dynamics, and examine the influence of patient age on impedance behavior.
Design: Retrospective cohort study.
Setting: Tertiary medical center.
Participants: A total of 554 ears underwent cochlear implantation between June 2006 and December 2014; each ear received 1 electrode array from 1 of 6 electrode types.
Exposure or Intervention: Longitudinal impedance data were analyzed across apical, medial, and basal electrode contacts at 7 time points.
Main Outcome Measures: Impedance trajectories varied by age group, electrode design, and cochlear region, with persistent changes observed up to 10 years.
Results: Impedance increased markedly from intraoperative to first activation in most arrays, although a significant decrease in apical contacts was observed in CI512 adults (P = .0008). Apical and medial contacts generally stabilized or declined thereafter. In contrast, basal electrodes exhibited more heterogeneous patterns, including increases during 12 to 60 months of follow-up and decreases during 60 to 120 months. Compared to PM arrays, LW electrodes showed higher apical impedances, medial impedances that were mostly comparable and time-dependent, and persistently lower basal impedances than CI512. Among LW arrays, CI422 consistently demonstrated the highest impedance, whereas the MED-EL electrode series, Flexsoft exhibited the highest impedance. Overall impedances were higher in early childhood recipients, while adults tended to show higher values in the basal region.
Conclusion: This study provides the first decade-long characterization of impedance changes, revealing dynamic variations in electrode impedance across different designs and age groups of cochlear implant recipients.
Relevance: This study highlights the need for long-term monitoring and offering practical guidance for individualized programming and electrode design.
Related
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BibTeX
@article{deng2026longterm,
title = {{Long-Term Impedance Trends Over 10 Years Following Cochlear Implantation: A Retrospective Comparative Analysis}},
author = {Jianhang Deng and Martin Koch and Matthias Bornitz and Sijia Zhai and Marcus Neudert and Till Moritz Essinger},
journal = {Journal of Otolaryngology - Head \& Neck Surgery},
year = {2026},
month = sep,
doi = {10.1177/19160216261442102},
url = {https://doi.org/10.1177/19160216261442102},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Long-Term Impedance Trends Over 10 Years Following Cochlear Implantation: A Retrospective Comparative Analysis
AU - Jianhang Deng
AU - Martin Koch
AU - Matthias Bornitz
AU - Sijia Zhai
AU - Marcus Neudert
AU - Till Moritz Essinger
PY - 2026
DA - 2026/09/28
JO - Journal of Otolaryngology - Head & Neck Surgery
DO - 10.1177/19160216261442102
UR - https://doi.org/10.1177/19160216261442102
AB - Importance: Impedance monitoring is a critical component of cochlear implant (CI) surgery, yet the lack of comprehensive longitudinal data limits the development of evidence-based postoperative monitoring guidelines, potentially compromising patient outcomes. Objective: To track impedance trends over 10 years post-implantation, evaluate the effects of electrode design on impedance dynamics, and examine the influence of patient age on impedance behavior. Design: Retrospective cohort study. Setting: Tertiary medical center. Participants: A total of 554 ears underwent cochlear implantation between June 2006 and December 2014; each ear received 1 electrode array from 1 of 6 electrode types. Exposure or Intervention: Longitudinal impedance data were analyzed across apical, medial, and basal electrode contacts at 7 time points. Main Outcome Measures: Impedance trajectories varied by age group, electrode design, and cochlear region, with persistent changes observed up to 10 years. Results: Impedance increased markedly from intraoperative to first activation in most arrays, although a significant decrease in apical contacts was observed in CI512 adults (P = .0008). Apical and medial contacts generally stabilized or declined thereafter. In contrast, basal electrodes exhibited more heterogeneous patterns, including increases during 12 to 60 months of follow-up and decreases during 60 to 120 months. Compared to PM arrays, LW electrodes showed higher apical impedances, medial impedances that were mostly comparable and time-dependent, and persistently lower basal impedances than CI512. Among LW arrays, CI422 consistently demonstrated the highest impedance, whereas the MED-EL electrode series, Flexsoft exhibited the highest impedance. Overall impedances were higher in early childhood recipients, while adults tended to show higher values in the basal region. Conclusion: This study provides the first decade-long characterization of impedance changes, revealing dynamic variations in electrode impedance across different designs and age groups of cochlear implant recipients. Relevance: This study highlights the need for long-term monitoring and offering practical guidance for individualized programming and electrode design.
SN - 1916-0208
SN - 1916-0216
ER -