Altered Cortical Activity in Prelingually Deafened

Authors: Marc J W Lammers Huib Versnel Gijsbert A van Zanten Wilko Grolman

Publish Date: 2014/10/15

Volume: 16, Issue: 1, Pages: 159-170

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Abstract

Auditory stimulation during childhood is critical for the development of the auditory cortex in humans and with that for hearing in adulthood Agerelated changes in morphology and peak latencies of the cortical auditory evoked potential CAEP have led to the use of this cortical response as a biomarker of auditory cortical maturation including studies of cortical development after deafness and subsequent cochlear implantation To date it is unknown whether prelingually deaf adults with early onset deafness before the age of 2 years and who received a cochlear implant CI only during adulthood would display absent or aberrant CAEP waveforms as predicted from CAEP studies in late implanted prelingually deaf children In the current study CAEP waveforms were recorded in response to electric stimuli in prelingually deaf adults who received their CI after the age of 21 years Waveform morphology and peak latencies were compared to the CAEP responses obtained in postlingually deaf adults who became deaf after the age of 16 Unexpectedly typical CAEP waveforms with adultlike P1N1P2 morphology could be recorded in the prelingually deaf adult CI users On visual inspection waveform morphology was comparable to the CAEP waveforms recorded in the postlingually deaf CI users Interestingly however latencies of the N1 peak were significantly shorter and amplitudes were significantly larger in the prelingual group than in the postlingual group The presence of the CAEP together with an early and large N1 peak might represent activation of the more innate and less complex components of the auditory cortex of the prelingually deaf CI user whereas the CAEP in postlingually deaf CI users might reflect activation of the mature neural network still present in these patients The CAEPs may therefore be helpful in the assessment of developmental state of the auditory cortex

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