Evolution of crossmodal reorganization of the voice area in cochlear-implanted deaf patients

Authors

  • Julien Rouger,

    1. Centre de recherche Cerveau et Cognition, Université Toulouse, Centre national de la recherche scientifique UMR 5549, Hôpital Purpan, Toulouse, France
    Current affiliation:
    1. Julien Rouger is currently at Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, University of Maastricht, The Netherlands
    Search for more papers by this author
  • Sébastien Lagleyre,

    1. Service d'oto-rhino-laryngologie et d'oto-neurologie, Hôpital Purpan, Toulouse, France
    Search for more papers by this author
  • Jean-François Démonet,

    1. Imagerie cérébrale et handicaps neurologiques, Université Toulouse, Institut national de la santé et de la recherche médicale U825, Hôpital Purpan, Toulouse, France
    Search for more papers by this author
  • Bernard Fraysse,

    1. Service d'oto-rhino-laryngologie et d'oto-neurologie, Hôpital Purpan, Toulouse, France
    Search for more papers by this author
  • Olivier Deguine,

    1. Centre de recherche Cerveau et Cognition, Université Toulouse, Centre national de la recherche scientifique UMR 5549, Hôpital Purpan, Toulouse, France
    2. Service d'oto-rhino-laryngologie et d'oto-neurologie, Hôpital Purpan, Toulouse, France
    Search for more papers by this author
  • Pascal Barone

    Corresponding author
    1. Centre de recherche Cerveau et Cognition, Université Toulouse, Centre national de la recherche scientifique UMR 5549, Hôpital Purpan, Toulouse, France
    • Centre de recherche Cerveau et Cognition, CNRS UMR 5549, Pavillon Baudot, Hôpital Purpan, BP 25202, 31052 Toulouse CEDEX, France
    Search for more papers by this author

  • Authors contribution: Julien Rouger and Sébastien Lagleyre contributed equally to this work.

Abstract

Psychophysical and neuroimaging studies in both animal and human subjects have clearly demonstrated that cortical plasticity following sensory deprivation leads to a brain functional reorganization that favors the spared modalities. In postlingually deaf patients, the use of a cochlear implant (CI) allows a recovery of the auditory function, which will probably counteract the cortical crossmodal reorganization induced by hearing loss. To study the dynamics of such reversed crossmodal plasticity, we designed a longitudinal neuroimaging study involving the follow-up of 10 postlingually deaf adult CI users engaged in a visual speechreading task. While speechreading activates Broca's area in normally hearing subjects (NHS), the activity level elicited in this region in CI patients is abnormally low and increases progressively with post-implantation time. Furthermore, speechreading in CI patients induces abnormal crossmodal activations in right anterior regions of the superior temporal cortex normally devoted to processing human voice stimuli (temporal voice-sensitive areas-TVA). These abnormal activity levels diminish with post-implantation time and tend towards the levels observed in NHS. First, our study revealed that the neuroplasticity after cochlear implantation involves not only auditory but also visual and audiovisual speech processing networks. Second, our results suggest that during deafness, the functional links between cortical regions specialized in face and voice processing are reallocated to support speech-related visual processing through cross-modal reorganization. Such reorganization allows a more efficient audiovisual integration of speech after cochlear implantation. These compensatory sensory strategies are later completed by the progressive restoration of the visuo-audio-motor speech processing loop, including Broca's area. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc

Ancillary