High homogeneity in auditory outcome of pediatric CI-patients with mutations in Gap-Junction-Protein Beta2

Abstract

Objectives A controversy exists in the literature regarding better auditory performance of cochlear implanted children with mutations in the Gap-Junction-Protein Beta2 (GJB2) gene. This is partially due to insufficient numbers, lack of proper statistics, etc. As this represents a very important issue for the counselling clinician, the aim of the study was to analyze auditive outcome in GJB2-related hearing loss in relation to other causes and review the literature. Methods Retrospective study. 44 children with unilateral cochlea implants were assigned into 3 groups according to their cause of deafness: group A contained 13 patients with GJB2-related deafness, group B 15 with hereditary hearing loss and negative GJB2-screening, and group C 16 with a nonhereditary cause. The auditory outcome performance was evaluated by pure-tone audiograms (PTA), the Monosyllabic-Trochee-Polysyllabic-Word Test (MTP) and the Listening Progress Profile (LiP) according to the EARS-protocol (Evaluation of Auditory Response to Speech) pre- and postoperatively up to 6.5 years. Additionally the educational setting was considered. Statistical analysis included direct comparison by using mixed models and computing the variance to test for homogeneity. Results A trend towards better performance for the GJB2 group (vs. the other groups combined) was observed regarding PTA, even more pronounced for LiP/MTP. However, a significant p-value was not reached. A high homogeneity, expressed by a significant difference in the variance of MTP and LiP was observed in the GJB2 group. Differences in educational setting were not significant. Conclusions The results of the study seem to support a better auditory performance of GJB2-patients with cochlea implants due to a cochlear origin of the defect. The significant homogeneity for this group is of paramount issue for the counselling clinician and a very important observation.