Flat-based fitting: the evaluation and usefulness of a new strategy-based fitting approach for cochlear implants

Cochlear Implantation: Long-Term Effect of Early Activation on Electrode Impedance

Objectives: The growing adoption of cochlear implants (CIs) necessitates understanding the factors influencing long-term performance and improved outcomes. This work investigated the long-term effect of early activation of CIs on electrode impedance in a large sample of CI users at different time points. Methods: A retrospective study on 915 ears from CI patients who were implanted between 2015 and 2020. According to their CI audio processor activation time, the patients were categorized into early activation (activated 1 day after surgery, n = 481) and classical activation (activated 4 weeks after surgery, n = 434) groups. Then, the impact of the activation times on the electrode impedance values, along the electrode array contacts, at different time points up to two years was studied and analyzed. Results: The early activation group demonstrated lower impedance values across all the electrode array sections compared to the classical activation at 1 month, 1 year, and 2 years post-implantation. At 1 month, early activation was associated with a reduction of 0.34 kΩ, 0.46 kΩ, and 0.37 kΩ in the apical, middle, and basal sections, respectively. These differences persisted at subsequent intervals. Conclusions: Early activation leads to sustained reductions in the electrode impedance compared to classical activation (CA), suggesting that earlier activation might positively affect long-term CI outcomes.

Effect of early activation of cochlear implant on electrode impedance in pediatric population

OBJECTIVES

To assess the evolution of electrode impedance after the early fitting of audio processors (activation after one-day) and classical fitting (activation after one-month) over an up-to-one year after cochlear implant (CI) surgery.

METHODS

A retrospective cohort study on Fifty-two CI recipients divided into two groups. The study group included 24 recipients (40 ears) who underwent early fitting, whereas the control group contained 28 recipients (40 ears) who underwent classical fitting. The electrode impedance was recorded during the surgery, switch-on session and at one, three, six, and twelve-months after the surgery.

RESULTS

In the study group, electrode impedance values obtained intraoperatively and at switch-on and one, three, six, and twelve-months were 4.89, 3.69, 6.52, 6.24, 6.05, and 5.81 KΩ, respectively, and only the switch-on and one-month values were significantly different (p < 0.0001). In the control group, electrode impedance values obtained intraoperatively and at switch-on and one, three, six, and twelve-months were 4.71, 7.19, 6.40, 6.05, and 5.73 KΩ, respectively. Thus, the electrode impedance value at switch-on was 52.65% (p < 0.001) greater than it intraoperatively. For both groups, the electrode impedance value at twelve-months was significantly higher than the respective intraoperative values (study group: 18.6% higher, P = 0.04; control group: 21.65% higher, P = 0.0001).

CONCLUSION

Electrode impedance was significantly lower in the study group compared to the control group until one month after the surgery. However, the electrode impedance at twelve-months after the CI was similar in both groups.