ELECTRIC AUDITORY BRAIN-STEM RESPONSES IN NUCLEUS MULTICHANNEL COCHLEAR IMPLANT USERS

Objective: The electrically elicited auditory brainstem response (EABR ) has been proposed as a tool for use in cochlear implant device setti ng. To systematically examine the relationships of psychophysical perc eptions and EABRs, implant users underwent a series of comparative mea surements. The characteristics of the EABR were assessed for their pre dictive value in determining the subjective measures needed to set the implant device. Design: Characteristics of the EABR and various perce ptual measures in a group of cochlear implant users served as compared variables in a correlational study. S Setting: The study was carried out in the audiology clinic of a university hospital. The audiology cl inic maintained a fully equipped evoked potential laboratory, and was part of an otolaryngology department that supported a cochlear implant program. Subjects: The subjects consisted of 10 consecutively selecte d postlinguistically deafened adult multichannel cochlear implant user s. Main Outcome Measures: Morphology, latency, and amplitude measures of the EABR recordings were compared with behavioral perceptions of th reshold, most comfortable and uncomfortable loudness levels. Results: Perceptual measures of threshold were found to be significantly relate d to the threshold of the EABR across subjects and electrode position. Simple linear regression analysis was used to measure the degree of t he relationship. An r value of 0.89 attests to a significant relations hip; The EABR wave latencies and amplitudes were found to have no sign ificant relationship to any of the perceptual measures examined. Concl usions: Although EABR cannot replace behavioral measurements for devic e setting, in difficult cases EABR thresholds may be used as a startin g point from which to estimate settings for the device.