Auditory Outcome After Cochlear Implantation in Patients With Congenital Nonsyndromic Hearing Loss: Influence of the GJB2 Status

Objective: To compare the audiologic outcome after cochlear implantation between 2 groups of patients with congenital nonsyndromic sensorineural hearing loss. Study Design: Retrospective cohort study. Setting: Department of Otorhinolaryngology, University hospital (tertiary referral center). Patients: From a bigger pool of implanted patients, 2 groups, each numbering 30 were enrolled. The patients from the first group were diagnosed with a Connexin 26 mutation (GJB2), whereas all of the patients from the second cohort were with a wild type genotype. Both groups were age matched, 1 to 7 years old at the age of implantation, with diagnosed congenital nonsyndromic sensorineural hearing loss. Main Outcome Measures: Both groups were evaluated with the help evaluation of auditory responses to speech/EARS/test battery - LiP test (Listening Progress Profile), MTP tests 3,6,12 (Monosyllabic-Trochee-Polysyllabic Test), GASP test (Glendonald Auditory Screening Procedure), and others. Follow-up period was at least 36 months. Results: Mean test scores were compared at the 1st, 6th, 12th, 24th, and 36th month. LiP outcome was significantly better (p G 0.05) for the GJB2-related cohort for the whole follow-up period except at the first month. MTP3, 6, and 12 tests displayed the same statistically significant outcome in favor of the first group. In the open-set test GASP, the difference was apparent: 1.22, 2.40, 5.59, and 7.40 mean scores at the 6th, 12th, 24th, and 36th months for the first cohort versus 0.00, 0.07, 0.81, and 1.74 for the GJB2-unrelated patients. Conclusion: The results from our study suggest that children with GJB2-related deafness show better auditory performance after cochlear implantation than age-matched children with GJB2-nonrelated sensorineural hearing loss.