Abstract

OBJECTIVE:

Cochlear implantation is a common treatment approach for children with auditory neuropathy/dyssynchrony (AN/AD) who do not benefit from hearing aids. The auditory brainstem response (ABR) is a measure of neural synchrony along the auditory pathway up through the brainstem. By definition, acoustically evoked ABR is absent in AN/AD, however, ABR can be elicited by electrical stimulation through the cochlear implant (electrically evoked ABR [EABR]). Reports of EABR with AN/AD to date have been primarily descriptive in nature. The objective of this study was to quantify EABR wave V measures in implanted children with and without AN/AD.

STUDY DESIGN:

Retrospective analysis of EABR waveforms from March 2000 through February 2005.

SETTING:

Comprehensive Cochlear Implant Program/Tertiary Referral Center.

PATIENTS:

Pediatric cochlear implant users of two etiologic groups: congenital AN/AD (n = 5) and other congenital profound sensorineural hearing loss (n = 27).

INTERVENTION:

Diagnostic.

MAIN OUTCOME MEASURES:

Intraoperative EABR wave V threshold, suprathreshold amplitude, and latency measures were compared between groups.

RESULTS:

The EABR threshold and suprathreshold amplitude measures across the population were variable regardless of etiology. With some exceptions, a trend was observed for the AN/AD group that included average or below-average thresholds and below-average suprathreshold response amplitudes.

CONCLUSION:

Cochlear implantation can provide synchronous neural responses to auditory stimulation in AN/AD, as previously known. The quantification of EABR measures in this study indicates that subjects with AN/AD have sufficient neural sensitivity to electrical stimulation, however, they may experience less robust neural responses at suprathreshold levels. Given the heterogeneity of potential causes of AN/AD, however, caution needs to be applied when grouping this population for analyses.