The effect of GJB2 allele variants on performance after cochlear implantation

Objectives/Hypothesis: It has been hypothesized that etiology of hearing loss may serve as an independent variable in performance after cochlear implantation. To test this hypothesis, the authors identified pediatric cochlear implant recipients with gap junction protein beta 2 (GJB2)-related deafness. The study examines performance outcomes associated with GJB2 deafness-causing allele variants. Study Design: Pediatric cochlear implant patients were screened for GJB2 allele variants; statistical comparisons were made with prospectively obtained performance measures. Methods. From 181 children who participated in a nationwide cochlear implant research program, 122 children were identified with congenital non-syndromic sensorineural hearing loss and invited to participate. Screening for GJB2 allele variants was completed for 55 children. The children were homogeneous with respect to age (8 or 9 y) and age at implant (before age 5 y). All patients have previously undergone a prospective regimented battery of performance measures. Results: Performance measures were compared between 22 children with and 33 children without mutations to determine whether GJB2 status was a significant predictor of cochlear implant outcomes. Reading and cognitive outcomes were significantly dependent on connexin status. The group of children who tested positive for GJB2-related deafness scored significantly higher on a nonverbal cognitive measure, Block Design, and on a measure of reading comprehension. Conclusion: The isolated insult to the cochlea created by GJB2 allele variants allows for preservation of central cognitive function. Better reading performance is seen in children with GJB2-related deafness.