Cochlear implant and hearing aid: a new approach to optimizing the fitting in this bimodal situation

More and more patients with residual hearing on the contralateral side are becoming candidates for cochlear implants (CI) surgery due to increasing CI. The major benefits of regular binaural hearing are spatial hearing, localization, and signal source discrimination in both quiet and noisy surroundings. In most of the reports, hearing aid fitting was carried out without balancing both the devices. Twelve children and eight adults with residual hearing on the non-operated side were binaurally fitted. Our fitting procedure for the hearing aid was based on the desired sensation level [i/o] method. A loudness scaling was used to adjust the loudness perception monaurally and to balance the volume of both devices. Speech audiometry in quiet and noisy surroundings was conducted both monaurally and in the bimodal mode. The fitting was modified according to the respective test results. In all children and six adults, a measurable gain and/or a subjective improvement of speech perception was achieved. Two adult patients did not accept the new fitting. In seven younger children, loudness scaling was impossible to perform because of age. This was also the case with speech audiometry for two children. A structured bimodal fitting using loudness scaling for both the cochlear implant and the hearing aid results in a subjective and objective amelioration of the patient's hearing and speech perception.