Cortical Speech Processing in Postlingually Deaf Adult Cochlear Implant Users, as Revealed by Functional Near-Infrared Spectroscopy
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Date
2018-07
Journal Title
Journal ISSN
Volume Title
Publisher
SAGE
Abstract
An experiment was conducted to investigate the feasibility of using functional near-infrared spectroscopy (fNIRS) to image
cortical activity in the language areas of cochlear implant (CI) users and to explore the association between the activity and
their speech understanding ability. Using fNIRS, 15 experienced CI users and 14 normal-hearing participants were imaged
while presented with either visual speech or auditory speech. Brain activation was measured from the prefrontal, temporal,
and parietal lobe in both hemispheres, including the language-associated regions. In response to visual speech, the activation
levels of CI users in an a priori region of interest (ROI)—the left superior temporal gyrus or sulcus—were negatively
correlated with auditory speech understanding. This result suggests that increased cross-modal activity in the auditory
cortex is predictive of poor auditory speech understanding. In another two ROIs, in which CI users showed significantly
different mean activation levels in response to auditory speech compared with normal-hearing listeners, activation levels
were significantly negatively correlated with CI users’ auditory speech understanding. These ROIs were located in the right
anterior temporal lobe (including a portion of prefrontal lobe) and the left middle superior temporal lobe. In conclusion,
fNIRS successfully revealed activation patterns in CI users associated with their auditory speech understanding.
Description
Keywords
Cochlear implant, Speech understanding, Functional near-infrared spectroscopy, Cortical activity
Citation
Zhou, X., A. K. Seghouane, A. Shah, H. Innes-Brown, W. Cross, R. Litovsky, and C. M. McKay. 2018. Cortical Speech Processing in Postlingually Deaf Adult Cochlear Implant Users, as Revealed by Functional Near-Infrared Spectroscopy. Trends in Hearing. 22: 2331216518786850.