PERIOPERATIVE ELECTRICAL AUDITORY BRAIN-STEM RESPONSE IN CANDIDATES FOR PEDIATRIC COCHLEAR IMPLANTATION

Objective: The aim was to investigate the feasibility of recording the electrical auditory brain stem response (EABR) evoked by electrical s timulation at the promontory (Prom-EABR) as a tool to assist selection of the ear for cochlear implantation in young children. Study Design: The study group consisted of young children for whom the decision to proceed with implantation with the Nucleus mini 22-channel cochlear im plant (Cochlear (UK) Ltd., London, UK) had already been made. Setting: The Prom-EABR was recorded after the children had been anesthetised, but before the start of surgery. Patients: A group of 25 children (11 boys and 14 girls), whose age at implantation ranged from 2 years 11 m onths to 6 years 8 months (mean age, 4 years 5 months), were investiga ted. Intervention: Recordings of the Prom-EABR were used to determine which ear would receive the cochlear implant, providing there were no preexisting contraindications regarding selection of the ear. Main Out come Measure: It has been suggested from earlier studies that the char acteristics of the amplitude input/output (I/O) function of the EABR a re related to neuronal survival. If the ear with the ''better'' I/O fu nction is chosen for implantation, it might be expected that these chi ldren will perform better on average than those in whom the ear has be en selected at random. Results: Reliable recordings of the Prom-EABR w ere achieved in 40 ears (80%) of the 50 ears in the study. In 20 of th e 25 children the technique was actively employed for selection of the ear for implantation. Conclusions: Recording of the Prom-EABR in the operating theater is a viable technique. Future analysis of long-term outcome measures of performance with the implant will confirm or dispu te the benefit of ear selection using the Prom-EABR.