Objectives: Impedance is a basic parameter registered at any cochlear implant fitting section. It is useful to monitor electrodes functioning and the status of the surrounding anatomical structures. The objective is to evaluate the 5-year impedance values trend in patients affected by congenital genetically determined profound hearing loss implanted with Cochlear® Nucleus™ devices.
Methods: Observational retrospective monocentric study.
Study sample: Twenty-seven consecutive patients (9 females, 12.0 ± 7.6 years old, range: 4.2 – 40.4) with genetic diagnosis of GJB2 mutation causing congenital profound hearing loss who underwent cochlear implantation from 2010 to 2020 with good auditory benefit. Impedance values of the cochlear implants were obtained from the cochlear implants’ programming software that registers those parameters for each follow up section of each patient.
Data Collection and Analysis: Impedance values were measured over time (activation, 6, 12, 24 and 60 months after cochlear implantation), for each of the 22 electrodes, in common ground (CG), Monopolar 1 (MP1), Monopolar 2 (MP2), and monopolar (MP1+2) stimulation modes. 
Repeated measures analysis of variance ruled out significant variations in impedance values from 6-month to 5-year follow-up.
Results: A significant variation was found between cochlear implant activation and 6-month follow-up. This difference was found for each of the 22 electrodes. Electrodes 1 to 4 showed higher impedance values compared to all other electrodes in each time interval.
Conclusions: Impedance values were extremely stable after activation, at least for the first 5 years. In these cases, even minimal impedance variations should be carefully evaluated for their possible implications on hearing performance.

Long-term impedance trend in cochlear implant users with genetically determined congenital profound hearing loss.

It is with great pleasure and enthusiasm, that on behalf of the Cochlear Implant centers of the Radboud UMC in Nijmegen and Erasmus MC Sophia Children’s Hospital in Rotterdam to invite you to attend the 16th European Symposium on Pediatric Cochlear Implantation to Rotterdam, the Netherlands in 2023.

Yours sincerely, on behalf of the CI Centers at Radboud UMC and Erasmus MC,