Novel Method of Fitting of Children with Auditory Brainstem Implants

To develop a reliable and objective fitting method for use with young children with an ABI.

17 young children were implanted with an ABI with the mean age 2 years and 4 months. eABR measurements were performed intraoperatively and at activation in order to record the auditory response and non-auditory side effects. Each child was tested to observe any subjective responses to the electric stimuli and non-auditory side effects. All children were fitted based on the postoperative eABR.

Intraoperatively an eABR could be obtained in all children. The responses were recordable from 75-100 % of all electrodes. At initial stimulation eABR were recordable in all children. The eABR was obtained in 79.7 % of all electrodes with a mean eABR threshold of 22.3 nC. eABR without any non-auditory stimulation was recorded on all electrodes in 11 children. Mixed eABR and non-auditory responses were recorded on 2-6 electrodes in 6 children. The subjective auditory responses for at least 1 electrode were noted in 15 children. In all children the subjective responses were within the estimated dynamic range for each electrode. The non-auditory response was observed only on children and electrodes with mixed eABR and non-auditory responses. The mean CAP score at 6 months after the activation was 2.4.

eABR seems to be a reliable tool to judge ABI electrode placement and a reliable method for fitting of young children with an ABI. The data suggest that eABR-based fitting helps children to more quickly achieve auditory perception and development.