Objective: To investigate the roles of genetic diagnosis and imaging studies, as well as other prognostic factors, in predicting outcomes in children with cochlear implant.
Design: Prospective cohort study.
Setting: Tertiary referral center.
Participants: Sixty-seven consecutive children with sensorineural hearing impairment who had at least 3 years of experience with cochlear implant.
Interventions: Imaging of the inner ear was done with high-resolution computed tomography, and mutations were screened in 3 genes commonly associated with pediatric hearing impairment: GJB2, SLC26A4, and the mitochondrial 12S ribosomal RNA gene. Speech perception performance was compared according to genetic diagnosis and imaging data. A general linear model was constructed to demonstrate the predictive values of specific genetic and imaging results after adjusting for other factors. Main Outcome Measure Recognition scores on speech perception tests.
Results: Twenty-two children (33%) showed genetic mutations: 18 with SLC26A4 and 4 with GJB2 mutations. According to imaging findings, 33 children (49%) showed inner ear malformations: 9 with a narrow internal auditory canal and 24 with other malformations. All children with SLC26A4 or GJB2 mutations exhibited excellent speech recognition scores, whereas a narrow internal auditory canal was associated with poorer outcomes (P < .001 in all recognition scores). The general linear model confirmed that both a narrow internal auditory canal (P < .001) and SLC26A4 mutations (P = .04) correlated with speech perception outcome.
Conclusions: Genetic diagnosis and imaging results are the 2 predominant factors determining the outcome in children with cochlear implants. In pediatric candidates for cochlear implantation, both genetic examination and imaging studies should be included in the battery of preoperative evaluations.