Objective: Cochlear implants (CIs) can partially restore hearing, but the cortical changes underlying auditory rehabilitation are not well understood.
Methods: This prospective longitudinal study used electroencephalography (EEG) to examine the temporal dynamics of changes in the auditory cortex contralateral and ipsilateral to the CI. Postlingually deafened CI recipients (N=11; mean: 59years) performed an auditory frequency discrimination task after <1week, 8weeks, 15weeks, and 59weeks of CI use.
Results: The CI users revealed a remarkable improvement in auditory discrimination ability which was most pronounced over the first eight weeks of CI experience. At the same time, CI users developed N1 auditory event-related potentials (AEP) with significantly enhanced amplitude and decreased latency, both in the auditory cortex contralateral and ipsilateral to the CI. A relationship was found between the duration of deafness and the ipsilateral AEP latency.
Conclusions: Postlingually deafened adult CI users show rapid adaptation of the bilateral auditory cortex. Cortical plasticity is limited after long duration of auditory deprivation.
Significance: The finding of rapid and limited cortical changes in adult CI recipients may be of clinical relevance and can help estimate the role of plasticity for therapeutic gain.
Keywords: Aging; Auditory cortex; Cochlear implant; Event-related potentials; Plasticity; Rehabilitation.
Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.