Implantation of the Malformed Cochlea

OBJECTIVE: This study assesses the results of cochlear implantation in children with cochlear malformations. STUDY DESIGN: Retrospective, matched-pairs analysis of prospectively collected data. SETTING: University-based regional cochlear implant center. PATIENTS: Seventeen children with osseous cochlear malformations who had undergone implantation were matched and compared with a group of children with normal cochleae who had undergone implantation. INTERVENTIONS: All subjects received a multichannel cochlear implant and habilitation. MAIN OUTCOME MEASURES: All subjects were tested with the Early Speech Perception test, and the Glendonald Auditory Speech Perception tests for words and sentences. Patients were classified in a standardized speech perception category based on performance on the Early Speech Perception test. RESULTS: All subjects demonstrated improving performance on all measures of speech perception over time. Overall, the two groups showed no statistically significant differences in performance at 6 and 24 months. However, subjects with malformed cochleae evidenced slower rates of improvement than did their matched control subjects. Subjects with more severe malformations demonstrated poorer performance, but this may have been attributable to preoperative factors rather than to implant performance. CONCLUSIONS: Children with radiographic cochlear malformations benefit from cochlear implantation with multichannel devices. They ultimately perform as well as their matched counterparts with normal cochleae, although they may improve more slowly over time.