gms | German Medical Science

Selection of cochlear implant candidates becomes difficult in cases affected by cochlear malformations. Evoked auditory brainstem responses (EABR) are useful to evaluate the auditory response to electrical stimulation, and therefore the viability of cochlear implantation. We record preoperative EABRs with electrical stimulation at promontory for evaluation of borderline candidates and intraopeartive EABRs with intracochlear stimulation in order to confirm the effectiveness of the implant.

A special electrode has been designed for stimulation at promontory. EABR responses are recorded at both ears for different stimulation levels. The responses are processed in order to reduce the stimulation artifact and are analyzed to obtain information for evaluation of the candidate and to select the ear to be implanted. 4 children affected by cochlear malformations are included in this study.

EABR responses were identified in all the cases, at least, at one ear. The ear with the best response was selected for cochlear implantation. The implanted device was a MED-EL Combi40+ in all these cases and the effectiveness of the implant was intraopeatively confirmed with EABR with stimulation from the implant. Preoperative and postoperative evaluations of auditory skills were performed. Results show a clear benefit from cochlear implantation for all these patients.

EABR is shown to be a valuable tool for selection of borderline candidates to cochlear implantation. This objective measurement provides evidence of cochlear nerve responses to electrical stimulation and is also useful for the selection of the ear to be implanted.