Objectives: To examine the relationships between psychophysical perceptions and the electrically evoked auditory brainstem responses (EABRs) in multichannel cochlear implant (CI) users and to determine the effectiveness of EABRs in electrode failure.
Design: A descriptive study reported the EABR characteristics while the different electrodes were activated. Characteristics of the EABR and of the perceptual measures served as compared variables in a correlational study.
Setting: The study was carried out in the audiology clinic of an otolaryngology department at a university hospital.
Patients: The subjects consisted of nine consecutively selected habitual Digisonic DX1OR multichannel CI users. Seven patients were postlinguistically deafened adult patients; two were congenitally deaf children.
Main outcome measures: Ipsilateral recordings were performed using a previously published method. Morphology, latency, and amplitude measures of the EABR recordings were described, computed, and compared with the literature data for EABRs obtained while activating other types of CI and for acoustically evoked ABRs. Correlations between EABRs and behavioral perception thresholds were analyzed using the parametric Pearson's correlation test.
Results: EABRs allowed the authors to detect failure of no. 10 electrode integrity in one child. Perceptual threshold measures were found to be highly significantly related to the EABR threshold across subjects and electrode position (n = 31, r = 0.98; P < 0.001; linear regression equation: perceptual threshold = 1.06 EABR threshold + 0.76). The latencies and amplitudes were found to be similar to those described in the literature.
Conclusions: EABRs may be used to estimate settings for the Digisonic DX10 CI even in a pediatric population, although they cannot entirely replace behavioral measurements, especially in children. The EABR can be employed for electrode dysfunction diagnosis. Further studies are needed to determine whether recordings of EABR quality could contribute to the evaluation of functional prognosis during the rehabilitation.