Publication:

Changes in response characteristics of cortical auditory evoked potentials in bilateral cochlear implantees

Background Cochlear implants (CIs) represents the most successful intervention to restore hearing in profoundly hearing impaired children and adults. An objective measures such as cortical auditory evoked potentials (CAEPs) would provide more insights to the auditory process involved in post implantation. Aim of the study was to profile the change in response characteristics of CAEPs in simultaneous binaural cochlear implantees. Objective was to measure change in latency and amplitude in monoaural and binaural condition for speech stimulus with change in intensities.

Methods Ours study is an observational retrospective study done at a tertiary ENT referral centre in south India, between Jan 2014 to Dec 2015. Out of total 15 patients with bilateral cochlear implantation, 7 consecutive bilateral simultaneous cochlear implantees with chronological age between 2-6 years were included in the study. Only pre-lingual congenital hearing loss children with no syndromic associations and normal cochlear anatomy were included while, peri-lingual, post-lingual children and children with sequential bilateral implantation were excluded from the study.

Results Amplitude of P1 was higher for binaural stimulation compared to monoaural stimulation. Latency of P1 was smaller for binaural compared to monoaural stimulus. In monaural stimulation the latency of P1 was smaller in right ear compared to left ear. However the difference between the right ear, left ear and binaural conditions were not statistically significant. Ours is a preliminary study and more bilateral implantees will be included in future studies to give more power to the study.

Conclusions We suggest that CAEPs can be used as a useful objective tool for assessment of post CI outcome.