MAP optimization as a predictor of cochlear implant outcomes in children with narrow internal auditory canal

The purposes of this study were to investigate the auditory performance and MAP characteristics of implanted children with narrow internal auditory canal (IAC), and to examine the clinical usefulness of MAP optimization as a predictor of their cochlear implant (CI) outcomes by analyzing their auditory performance and habilitation methods in relation to MAP optimization.

Eight children with narrow IAC who had used a CI over 3 years were included. We retrospectively examined their auditory performance and MAPs. Auditory performance was measured by the Categories of Auditory Performance (CAP) and monosyllabic word tests before and after implantation. The relationship between auditory performance and MAP parameters was explored, and their habilitation methods were analyzed.

Mean CAP scores improved from .25 preoperatively to 3.5 3 years postoperatively. Mean scores for monosyllabic word tests improved from 0% preoperatively to 27.8% 3 years postoperatively. The children used MAPs with a wider pulse width than the default setting. Four children using optimal MAPs achieved open-set speech perception, so were trained in the oral approach. The other four using suboptimal MAPs because of non-auditory stimulation achieved no open-set speech perception, so were trained in the total communication approach.

MAP optimization had a predictable value in determining the postoperative performance of children with narrow IAC who received a CI. The most suitable habilitation method can be determined early after implantation by identifying the presence of MAP optimization.