Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.

Hearing impairment alters the sound input received by the human auditory system, reducing speech comprehension in noisy multi-talker auditory scenes. Despite such difficulties, neural signals were shown to encode the attended speech envelope more reliably than the envelope of ignored sounds, reflect...

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Main Authors: Sara Carta, Emina Aličković, Johannes Zaar, Alejandro López Valdés, Giovanni M Di Liberto
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0308554
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author Sara Carta
Emina Aličković
Johannes Zaar
Alejandro López Valdés
Giovanni M Di Liberto
author_facet Sara Carta
Emina Aličković
Johannes Zaar
Alejandro López Valdés
Giovanni M Di Liberto
author_sort Sara Carta
collection DOAJ
description Hearing impairment alters the sound input received by the human auditory system, reducing speech comprehension in noisy multi-talker auditory scenes. Despite such difficulties, neural signals were shown to encode the attended speech envelope more reliably than the envelope of ignored sounds, reflecting the intention of listeners with hearing impairment (HI). This result raises an important question: What speech-processing stage could reflect the difficulty in attentional selection, if not envelope tracking? Here, we use scalp electroencephalography (EEG) to test the hypothesis that the neural encoding of phonological information (i.e., phonetic boundaries and phonological categories) is affected by HI. In a cocktail-party scenario, such phonological difficulty might be reflected in an overrepresentation of phonological information for both attended and ignored speech sounds, with detrimental effects on the ability to effectively focus on the speaker of interest. To investigate this question, we carried out a re-analysis of an existing dataset where EEG signals were recorded as participants with HI, fitted with hearing aids, attended to one speaker (target) while ignoring a competing speaker (masker) and spatialised multi-talker background noise. Multivariate temporal response function (TRF) analyses indicated a stronger phonological information encoding for target than masker speech streams. Follow-up analyses aimed at disentangling the encoding of phonological categories and phonetic boundaries (phoneme onsets) revealed that neural signals encoded the phoneme onsets for both target and masker streams, in contrast with previously published findings with normal hearing (NH) participants and in line with our hypothesis that speech comprehension difficulties emerge due to a robust phonological encoding of both target and masker. Finally, the neural encoding of phoneme-onsets was stronger for the masker speech, pointing to a possible neural basis for the higher distractibility experienced by individuals with HI.
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spelling doaj-art-7d3b56c3c4da486bb9677b16b34791062025-08-20T01:53:22ZengPublic Library of Science (PLoS)PLoS ONE1932-62032024-01-011911e030855410.1371/journal.pone.0308554Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.Sara CartaEmina AličkovićJohannes ZaarAlejandro López ValdésGiovanni M Di LibertoHearing impairment alters the sound input received by the human auditory system, reducing speech comprehension in noisy multi-talker auditory scenes. Despite such difficulties, neural signals were shown to encode the attended speech envelope more reliably than the envelope of ignored sounds, reflecting the intention of listeners with hearing impairment (HI). This result raises an important question: What speech-processing stage could reflect the difficulty in attentional selection, if not envelope tracking? Here, we use scalp electroencephalography (EEG) to test the hypothesis that the neural encoding of phonological information (i.e., phonetic boundaries and phonological categories) is affected by HI. In a cocktail-party scenario, such phonological difficulty might be reflected in an overrepresentation of phonological information for both attended and ignored speech sounds, with detrimental effects on the ability to effectively focus on the speaker of interest. To investigate this question, we carried out a re-analysis of an existing dataset where EEG signals were recorded as participants with HI, fitted with hearing aids, attended to one speaker (target) while ignoring a competing speaker (masker) and spatialised multi-talker background noise. Multivariate temporal response function (TRF) analyses indicated a stronger phonological information encoding for target than masker speech streams. Follow-up analyses aimed at disentangling the encoding of phonological categories and phonetic boundaries (phoneme onsets) revealed that neural signals encoded the phoneme onsets for both target and masker streams, in contrast with previously published findings with normal hearing (NH) participants and in line with our hypothesis that speech comprehension difficulties emerge due to a robust phonological encoding of both target and masker. Finally, the neural encoding of phoneme-onsets was stronger for the masker speech, pointing to a possible neural basis for the higher distractibility experienced by individuals with HI.https://doi.org/10.1371/journal.pone.0308554
spellingShingle Sara Carta
Emina Aličković
Johannes Zaar
Alejandro López Valdés
Giovanni M Di Liberto
Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
PLoS ONE
title Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
title_full Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
title_fullStr Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
title_full_unstemmed Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
title_short Cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals.
title_sort cortical encoding of phonetic onsets of both attended and ignored speech in hearing impaired individuals
url https://doi.org/10.1371/journal.pone.0308554
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AT alejandrolopezvaldes corticalencodingofphoneticonsetsofbothattendedandignoredspeechinhearingimpairedindividuals
AT giovannimdiliberto corticalencodingofphoneticonsetsofbothattendedandignoredspeechinhearingimpairedindividuals