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 stimulation 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 implant (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 months to 6 years 8 months (mean age, 4 years 5 months), were investigated.

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 OUTCOME MEASURE

It has been suggested from earlier studies that the characteristics of the amplitude input/output (I/O) function of the EABR are related to neuronal survival. If the ear with the "better" I/O function is chosen for implantation, it might be expected that these children will perform better on average than those in whom the ear has been selected at random.

RESULTS

Reliable recordings of the Prom-EABR were achieved in 40 ears (80%) of the 50 ears in the study. In 20 of the 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 dispute the benefit of ear selection using the Prom-EABR.