Electrophysiological and speech perception measures of auditory processing in experienced adult cochlear implant users

Abstract

Objective This study determined the relationship between auditory evoked potential measures and speech perception in experienced adult cochlear implant (CI) users and compared the CI evoked potential results to those of a group of age- and sex-matched control subjects. Methods CI subjects all used the Nucleus CI-22 implant. Middle latency response (MLR), obligatory cortical potentials (CAEP), mismatch negativity (MMN) and P3a auditory evoked potentials were recorded. Speech perception was evaluated using word and sentence tests. Results Duration of deafness correlated with speech scores with poor scores reflecting greater years of deafness. Na amplitude correlated negatively with duration of deafness, with small amplitudes reflecting greater duration of deafness. Overall, N1 amplitude was smaller in CI than control subjects. Earlier P2 latencies were associated with shorter durations of deafness and higher speech scores. In general, MMN was absent or degraded in CI subjects with poor speech scores. Conclusions Auditory evoked potentials are related to speech perception ability and provide objective evidence of central auditory processing differences across experienced CI users. Significance Since auditory evoked potentials relate to CI performance, they may be a useful tool for objectively evaluating the efficacy of speech processing strategies and/or auditory training approaches in both adults and children with cochlear implants.