Cochlear implantation in children with cochlear nerve deficiency.

OBJECTIVE: The aim of this study was to report on auditory performance after cochlear implantation in children with cochlear nerve deficiency.

METHODS: A retrospective case review was performed. Five patients with pre-lingual profound sensorineural hearing loss implanted in an ear with cochlear nerve deficiency participated in the study. Postoperative auditory and speech performance was assessed using warble tone average threshold with cochlear implant, speech perception categories, and speech intelligibility ratings. All patients underwent high resolution computed tomography and magnetic resonance imaging.

RESULTS: According to Govaerts classification, three children had a type IIb and two a type IIa cochlear nerve deficiency. Preoperatively, four patients were placed into speech perception category 1 and one into category 2. All patients had an improvement in hearing threshold with the cochlear implant. Despite this, at the last follow-up (range 18-81 months, average 45 months), only one girl benefited from cochlear implantation; she moved from speech perception category 2 to 6 and developed spoken language. Another child developed closed set speech perception and had connected speech that was unintelligible. The other 3 children showed little benefit from the cochlear implant and obtained only an improved access to environmental sounds and improved lipreading skills. None of these 4 children developed a spoken language, but they were all full-time users of their implants.

CONCLUSIONS: The outcomes of cochlear implantation in these five children with cochlear nerve deficiency are extremely variable, ranging from sporadic cases in which open set speech perception and acquisition of a spoken language are achieved, to most cases in which only an improved access to environmental sound develops. Regardless of these limited outcomes, all patients in our series use their device on a daily basis and derive benefits in everyday life. In our opinion, cochlear implantation can be a viable option in children with cochlear nerve deficiency, but careful counseling to the family on possible restricted benefit is needed.