Speech Perception Outcomes after Cochlear Implantation in Children with GJB2/DFNB1 associated Deafness

Background: Cochlear implants (CI) for the rehabilitation of patients with profound or total bilateral sensorineural hypoacusis represent the initial use of electrical fields to provide audibility in cases where the use of sound amplifiers does not provide satisfactory results. Aims: To compare speech perception performance after cochlear implantation in children with connexin 26-associated deafness with that of a control group of children with deafness of unknown etiology. Study Design: Retrospective comparative study. Methods: During the period from 2006 to, cochlear implantation was performed on 26 children. Eighteen of these children had undergone genetic tests for mutation of the Gap Junction Protein Beta 2 (GJB2) gene. Bi-allelic GJB2 mutations were confirmed in 7 out of 18 examined children. In order to confirm whether genetic factors have influence on speech perception after cochlear implantation, we compared the post-implantation speech performance of seven children with mutations of the GBJ2 (connexin 26) gene with seven other children who had the wild type version of this particular gene. The latter were carefully matched according to the age at cochlear implantation. Speech perception performance was measured before cochlear implantation, and one and two years after implantation. All the patients were arranged in line with the appropriate speech perception category (SPC). Non-parametric tests, Friedman ANOVA and Mann-Whitney's U test were used for statistical analysis. Results: Both groups showed similar improvements in speech perception scores after cochlear implantation. Statistical analysis did not confirm significant differences between the groups 12 and 24 months after cochlear implantation. Conclusion: The results obtained in this study showed an absence of apparent distinctions in the scores of speech perception between the two examined groups and therefore might have significant implications in selecting prognostic indicators of speech perception following cochlear implantation.