Perceptual outcomes in children with auditory brainstem implants

Abstract

In previous studies, only patients with neurofibromatosis type 2 older than 12 years have been considered as candidates for an auditory brainstem implant (ABI). Our study now extends the potential criteria to include children with other cochlear or cochlear nerve malfunctions who either would not benefit at all from a cochlear implant (e.g. cochlear nerve aplasia or avulsion) or would receive only severely compromised benefit (e.g. cochlear ossification). In our department, over the period from April 1997 to April 2004, 10 children were fitted with ABIs. Their ages ranged from 14 months to 16 years. Two children had neurofibromatosis type 2, and five bilateral cochlear nerve aplasia, 2 of whom with associated unilateral facial nerve agenesia. One of these children had previously been fitted twice with a cochlear implant in the same ear during the same session. One child was suffering from auditory neuropathy and had previously been fitted with a cochlear implant that yielded no benefit. One child showed complete cochlear ossification, one had cochlear malformations and one had profound hearing loss following a head injury. A retrosigmoid-transmeatal approach was used in the tumor patients and a retrosigmoid approach in the non-tumor patients. Correct implantation was achieved in all patients. No complications due to implantation surgery or related to ABI activation or long-term use were observed. Auditory sensations were induced in all 10 patients with various numbers of electrodes (from 5 to 15). The indications for ABI can be extended to include children with severe cochlear and/or cochlear nerve abnormalities, such as cochlear nerve aplasia, cochlear malformation or complete ossification of the cochlea, or cochlear nerve disruption due to head injury.