Metachronous cochlear implantation in children

Overview

Objective: The aim of the study was to evaluate audiological outcomes in children with prelingual hearing loss after sequential cochlear implantation and to compare them with a group of children who underwent simultaneous implantation. In addition, we investigated how the length of the inter-implant interval influences audiological outcomes of the second implanted ear and whether delayed contralateral implantation may provide clinical benefit. Material and methods: This retrospective study included children with bilateral prelingual severe to profound sensorineural hearing loss who underwent bilateral cochlear implantation. Patients were divided into three groups: synchronous implantation, sequential implantation with a short inter-implant interval (≤ 5 years), and sequential implantation with a long inter-implant interval (> 5 years). The following parameters were evaluated: mean aided thresholds (gain curves), Speech reception threshold (SRT) for each ear separately and bilaterally, and daily device use (datalogging). Data was analysed using non-parametric statistical methods. Results: Simultaneous implantation and sequential implantation with a short inter-implant interval resulted in symmetrical audiological outcomes and balanced use of both implants. In the group with a long inter-implant interval, a statistically significant asymmetry was found in SRT values (mean difference 18.6 dB) and in daily device use (mean difference 4.23 hours/day; P < 0.01). Nevertheless, the second implanted ear remained functionally utilized. Conclusion: From the perspective of central auditory development, simultaneous or early sequential implantation appears to be optimal. However, the results confirm that even delayed second-side implantation provides clinical benefit and should not be routinely rejected.

Keywords:

cochlear implantation – metachronous implantation – sequential implantation – inter-implant interval – datalogging