Functional localization of audiovisual speech using near infrared spectroscopy.

Content Provider	Europe PMC
Author	Butera, Iliza M. Larson, Eric D. DeFreese, Andrea J. Lee, Adrian KC Gifford, René H. Wallace, Mark T.
Abstract	Visual cues are especially vital for hearing impaired individuals such as cochlear implant (CI) users to understand speech in noise. Functional Near Infrared Spectroscopy (fNIRS) is a light-based imaging technology that is ideally suited for measuring the brain activity of CI users due to its compatibility with both the ferromagnetic and electrical components of these implants. In a preliminary step toward better elucidating the behavioral and neural correlates of audiovisual (AV) speech integration in CI users, we designed a speech-in-noise task and measured the extent to which 24 normal hearing individuals could integrate the audio of spoken monosyllabic words with the corresponding visual signals of a female speaker. In our behavioral task, we found that audiovisual pairings provided average improvements of 103% and 197% over auditory-alone listening conditions in −6 and −9 dB signal-to-noise ratios consisting of multi-talker background noise. In an fNIRS task using similar stimuli, we measured activity during auditory-only listening, visual-only lipreading, and AV listening conditions. We identified cortical activity in all three conditions over regions of middle and superior temporal cortex typically associated with speech processing and audiovisual integration. In addition, three channels active during the lipreading condition showed uncorrected correlations associated with behavioral measures of audiovisual gain as well as with the McGurk effect. Further work focusing primarily on the regions of interest identified in this study could test how AV speech integration may differ for CI users who rely on this mechanism for daily communication.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10548-022-00904-1.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC9334437&blobtype=pdf
ISSN	08960267
Journal	Brain Topography [Brain Topogr]
Volume Number	35
DOI	10.1007/s10548-022-00904-1
PubMed Central reference number	PMC9334437
Issue Number	4
PubMed reference number	35821542
e-ISSN	15736792
Language	English
Publisher	Springer US
Publisher Date	2022-07-12
Publisher Place	New York
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2022
Subject Keyword	Multisensory integration fNIRS Infrared spectroscopy Speech in noise McGurk effect
Content Type	Text
Resource Type	Article
Subject	Anatomy Neurology Radiology, Nuclear Medicine and Imaging Neurology (clinical) Radiological and Ultrasound Technology