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Pre- and post-target cortical processes predict speech-in-noise performance
Journal article   Open access   Peer reviewed

Pre- and post-target cortical processes predict speech-in-noise performance

Subong Kim, Adam T Schwalje, Andrew S Liu, Phillip E Gander, Bob McMurray, Timothy D Griffiths and Inyong Choi
NeuroImage (Orlando, Fla.), Vol.228, pp.117699-117699
03/2021
DOI: 10.1016/j.neuroimage.2020.117699
PMID: 33387631
url
https://doi.org/10.1016/j.neuroimage.2020.117699View
Published (Version of record) Open Access

Abstract

Understanding speech in noise (SiN) is a complex task that recruits multiple cortical subsystems. There is a variance in individuals’ ability to understand SiN that cannot be explained by simple hearing profiles, which suggests that central factors may underlie the variance in SiN ability. Here, we elucidated a few cortical functions involved during a SiN task and their contributions to individual variance using both within- and across-subject approaches. Through our within-subject analysis of source-localized electroencephalography, we investigated how acoustic signal-to-noise ratio (SNR) alters cortical evoked responses to a target word across the speech recognition areas, finding stronger responses in left supramarginal gyrus (SMG, BA40 the dorsal lexicon area) with quieter noise. Through an individual differences approach, we found that listeners show different neural sensitivity to the background noise and target speech, reflected in the amplitude ratio of earlier auditory-cortical responses to speech and noise, named as an internal SNR. Listeners with better internal SNR showed better SiN performance. Further, we found that the post-speech time SMG activity explains a further amount of variance in SiN performance that is not accounted for by internal SNR. This result demonstrates that at least two cortical processes contribute to SiN performance independently: pre-target time processing to attenuate neural representation of background noise and post-target time processing to extract information from speech sounds.
Speech-in-noise Electroencephalography Supramarginal gyrus Speech unmasking Speech recognition Individual differences

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