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Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents

Unilateral auditory deprivation in early childhood can lead to cortical strengthening of inputs from the stimulated side, yet the impact of this on bilateral processing when inputs are later restored beyond an early sensitive period is unknown. To address this, we conducted a longitudinal study with...

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Autores principales: Anderson, Carly A., Cushing, Sharon L., Papsin, Blake C., Gordon, Karen A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley & Sons, Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9294307/
https://www.ncbi.nlm.nih.gov/pubmed/35429083
http://dx.doi.org/10.1002/hbm.25875
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author Anderson, Carly A.
Cushing, Sharon L.
Papsin, Blake C.
Gordon, Karen A.
author_facet Anderson, Carly A.
Cushing, Sharon L.
Papsin, Blake C.
Gordon, Karen A.
author_sort Anderson, Carly A.
collection PubMed
description Unilateral auditory deprivation in early childhood can lead to cortical strengthening of inputs from the stimulated side, yet the impact of this on bilateral processing when inputs are later restored beyond an early sensitive period is unknown. To address this, we conducted a longitudinal study with 13 bilaterally profoundly deaf adolescents who received unilateral access to sound via a cochlear implant (CI) in their right ear in early childhood before receiving bilateral access to sound a decade later via a second CI in their left ear. Auditory‐evoked cortical responses to unilateral and bilateral stimulation were measured repeatedly using electroencephalogram from 1 week to 14 months after activation of their second CI. Early cortical responses from the newly implanted ear and bilateral stimulation were atypically lateralized to the left ipsilateral auditory cortex. Duration of unilateral deafness predicted an unexpectedly stronger representation of inputs from the newly implanted, compared to the first implanted ear, in left auditory cortex. Significant initial reductions in responses were observed, yet a left‐hemisphere bias and unequal weighting of inputs favoring the long‐term deaf ear did not converge to a balanced state observed in the binaurally developed system. Bilateral response enhancement was significantly reduced in left auditory cortex suggesting deficits in ipsilateral response inhibition of new, dominant, inputs during bilateral processing. These findings paradoxically demonstrate the adaptive capacity of the adolescent auditory system beyond an early sensitive period for bilateral input, as well as restrictions on its potential to fully reverse cortical imbalances driven by long‐term unilateral deafness.
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spelling pubmed-92943072022-07-20 Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents Anderson, Carly A. Cushing, Sharon L. Papsin, Blake C. Gordon, Karen A. Hum Brain Mapp Research Articles Unilateral auditory deprivation in early childhood can lead to cortical strengthening of inputs from the stimulated side, yet the impact of this on bilateral processing when inputs are later restored beyond an early sensitive period is unknown. To address this, we conducted a longitudinal study with 13 bilaterally profoundly deaf adolescents who received unilateral access to sound via a cochlear implant (CI) in their right ear in early childhood before receiving bilateral access to sound a decade later via a second CI in their left ear. Auditory‐evoked cortical responses to unilateral and bilateral stimulation were measured repeatedly using electroencephalogram from 1 week to 14 months after activation of their second CI. Early cortical responses from the newly implanted ear and bilateral stimulation were atypically lateralized to the left ipsilateral auditory cortex. Duration of unilateral deafness predicted an unexpectedly stronger representation of inputs from the newly implanted, compared to the first implanted ear, in left auditory cortex. Significant initial reductions in responses were observed, yet a left‐hemisphere bias and unequal weighting of inputs favoring the long‐term deaf ear did not converge to a balanced state observed in the binaurally developed system. Bilateral response enhancement was significantly reduced in left auditory cortex suggesting deficits in ipsilateral response inhibition of new, dominant, inputs during bilateral processing. These findings paradoxically demonstrate the adaptive capacity of the adolescent auditory system beyond an early sensitive period for bilateral input, as well as restrictions on its potential to fully reverse cortical imbalances driven by long‐term unilateral deafness. John Wiley & Sons, Inc. 2022-04-15 /pmc/articles/PMC9294307/ /pubmed/35429083 http://dx.doi.org/10.1002/hbm.25875 Text en © 2022 The Authors. Human Brain Mapping published by Wiley Periodicals LLC. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Anderson, Carly A.
Cushing, Sharon L.
Papsin, Blake C.
Gordon, Karen A.
Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title_full Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title_fullStr Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title_full_unstemmed Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title_short Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
title_sort cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9294307/
https://www.ncbi.nlm.nih.gov/pubmed/35429083
http://dx.doi.org/10.1002/hbm.25875
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