This study examined the effects of bilateral and unilateral deafness by measuring cortical auditory evoked potential (CAEP) responses in children at initial stages of bilateral cochlear implant (CI) use. We recorded cortical responses evoked by right and left CI stimulation in 127 children with early onset (< 12 months) deafness, with 72 children receiving the two devices in the same surgery (simultaneously implanted) and 55 children receiving the devices in separate procedures (sequentially implanted). Three different types of responses were identified in children with bilateral CIs. No significant effects of duration of deafness, age at implantation, or duration of unilateral CI use were found on response latencies and amplitudes within each type of cortical response, but there were clear differences in responses types between groups and ears. In the context of these findings, the effects of bilateral and unilateral deafness to the auditory pathways were discussed.

This study examined the effects of bilateral and unilateral deafness by measuring cortical auditory evoked potential (CAEP) responses in children at initial stages of bilateral cochlear implant (CI) use. We recorded cortical responses evoked by right and left CI stimulation in 127 children with early onset (< 12 months) deafness, with 72 children receiving the two devices in the same surgery (simultaneously implanted) and 55 children receiving the devices in separate procedures (sequentially implanted). Three different types of responses were identified in children with bilateral CIs. No significant effects of duration of deafness, age at implantation, or duration of unilateral CI use were found on response latencies and amplitudes within each type of cortical response, but there were clear differences in responses types between groups and ears. In the context of these findings, the effects of bilateral and unilateral deafness to the auditory pathways were discussed.