Cortical plasticity with bimodal hearing in children with asymmetric hearing loss

Melissa J. Polonenko, Blake C. Papsin, Karen A. Gordon

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


This longitudinal study aimed to identify auditory plasticity promoted by a cochlear implant in children with asymmetric hearing loss. Participants included 10 children who experienced (mean ± SD) 3.1 ± 3.6 years of asymmetric hearing (difference of 47.2 ± 47.6 dB) before receiving an implant at age 8.7 ± 5.1 years. Multi-channel electroencephalography was measured at initial implant use (5.8 ± 3.2 days) and after 10.2 ± 4.1 months in each child. Monaurally presented stimuli consisted of 36 ms trains of 9 acoustic clicks/biphasic electric pulses at a rate of 250 Hz, repeated at 1 Hz. The time-restricted artifact and coherent source suppression (TRACS) beamformer was used to locate sources underlying peak amplitudes of cortical responses. Results indicated consistent activity from the non-implanted ear but significant implant-driven changes to the auditory cortices. Initially, the newly implanted ear evoked activity which strongly lateralized to the ipsilateral auditory cortex and contributed to a significant aural preference for implant stimulation in children with limited acoustic experience pre-implantation. Cochlear implant use reversed these abnormalities, but the resolution was limited in children with longer periods of asymmetric hearing. These findings suggest that early implantation of children with asymmetric hearing rapidly restores hemispheric representations of bilateral auditory input in the auditory cortex. Most recorded changes were isolated to pathways stimulated by the cochlear implant, potentially reflecting an abnormal independence of the bilateral pathways with possible consequences for binaural integration in these bimodal listeners.

Original languageEnglish (US)
Pages (from-to)88-98
Number of pages11
JournalHearing Research
StatePublished - Feb 2019
Externally publishedYes

Bibliographical note

Funding Information:
We gratefully recognize the time and support of the children and families who participated in this study. We also thank Alexander Andrews for support in creating the stimuli, Salima Jiwani for initial beamforming analysis support, and Stephanie Jewell for data collection support. Funding for this project was provided by the Canadian Institutes of Health Research ( MOP-97924 to KAG and BCP, MFE-1748241 to MJP), The Hospital for Sick Children Research Institute (Clinician-Scientist Training Program Studentship and Research Training Competition Award to MJP), and the Ontario Ministry of Ministry of Advanced Education and Skills Development with The University of Toronto ( Ontario Graduate Doctoral Scholarship for MJP), and the University of Toronto (Studentship Funding for MJP).

Publisher Copyright:
© 2018 Elsevier B.V.


  • Asymmetric hearing loss
  • Auditory cortex
  • Auditory evoked potentials
  • Bimodal hearing
  • Cochlear implant
  • Development
  • EEG
  • Unilateral deafness


Dive into the research topics of 'Cortical plasticity with bimodal hearing in children with asymmetric hearing loss'. Together they form a unique fingerprint.

Cite this