scholarly journals Degradation levels of continuous speech affect neural speech tracking and alpha power differently

2020 ◽  
Author(s):  
Anne Hauswald ◽  
Anne Keitel ◽  
Ya‐Ping Chen ◽  
Sebastian Rösch ◽  
Nathan Weisz
Keyword(s):  
Alpha Power ◽  
Continuous Speech ◽  
Speech Tracking

scholarly journals Degradation levels of continuous speech affect neural speech tracking and alpha power differently

2019 ◽  
Author(s):  
Anne Hauswald ◽  
Anne Keitel ◽  
Ya-Ping Chen ◽  
Sebastian Rösch ◽  
Nathan Weisz
Keyword(s):  
Speech Intelligibility ◽  
Low Frequency ◽  
Alpha Power ◽  
Continuous Speech ◽  
Floor Effect ◽  
Degraded Speech ◽  
Two Measures ◽  
Hearing Damage ◽  
Study Participants ◽  
Speech Tracking

AbstractUnderstanding degraded speech, e.g. following a hearing damage, can pose a challenge. Previous attempts to quantify speech intelligibility in neural terms have usually focused on one of two measures, namely low-frequency speech-brain synchronization or alpha power modulations. However, reports have been mixed concerning the modulation of these measures, an issue aggravated by the fact that they have normally been studied separately. Using a parametric speech degradation approach, we present MEG studies that overcome this shortcoming. In a first study, participants listened to unimodal auditory speech with three different levels of degradation (original, 7-channel and 3-channel vocoding). Intelligibility declined with declining clarity, implemented by fewer vocoding channels but was still intelligible to some extent even for the lowest clarity level used (3-channel vocoding). Low- frequency (1-7 Hz) speech tracking suggested a u-shaped relationship with strongest effects for the medium degraded speech (7-channel) in bilateral auditory and left frontal regions. To follow up on this finding, we implemented three additional vocoding levels (5-channel, 2- channel, 1-channel) in a second MEG study. Using this wider range of degradation, the speech-brain synchronization showed a similar pattern for the degradation levels used in the first study but further shows that when speech becomes unintelligible, synchronization declines again. The relationship differed for alpha power, which continued to decrease across vocoding levels reaching a floor effect for 5-channel vocoding. Predicting subjective intelligibility based on models either combining both measures or each measure alone, showed superiority of the combined model. Our findings underline that speech tracking and alpha power are modified differently by the degree of degradation of continuous speech but together contribute to the subjective understanding of speech.

scholarly journals Neural attentional-filter mechanisms of listening success in middle-aged and older individuals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sarah Tune ◽  
Mohsen Alavash ◽  
Lorenz Fiedler ◽  
Jonas Obleser
Keyword(s):  
Ageing Population ◽  
Alpha Power ◽  
Older Individuals ◽  
Single Trial ◽  
Neural Filter ◽  
Information Research ◽  
Behavioural Performance ◽  
Neural Marker ◽  
Attentional Filter ◽  
Speech Tracking

AbstractSuccessful listening crucially depends on intact attentional filters that separate relevant from irrelevant information. Research into their neurobiological implementation has focused on two potential auditory filter strategies: the lateralization of alpha power and selective neural speech tracking. However, the functional interplay of the two neural filter strategies and their potency to index listening success in an ageing population remains unclear. Using electroencephalography and a dual-talker task in a representative sample of listeners (N = 155; age=39–80 years), we here demonstrate an often-missed link from single-trial behavioural outcomes back to trial-by-trial changes in neural attentional filtering. First, we observe preserved attentional–cue-driven modulation of both neural filters across chronological age and hearing levels. Second, neural filter states vary independently of one another, demonstrating complementary neurobiological solutions of spatial selective attention. Stronger neural speech tracking but not alpha lateralization boosts trial-to-trial behavioural performance. Our results highlight the translational potential of neural speech tracking as an individualized neural marker of adaptive listening behaviour.

scholarly journals Individual listening success explained by synergistic interaction of two distinct neural filters

2019 ◽  
Author(s):  
Sarah Tune ◽  
Lorenz Fiedler ◽  
Mohsen Alavash ◽  
Jonas Obleser
Keyword(s):  
Occipital Cortex ◽  
Synergistic Interaction ◽  
Speech Comprehension ◽  
Alpha Power ◽  
Dichotic Listening Task ◽  
Neurophysiological Studies ◽  
Cortical Responses ◽  
Neural Filter ◽  
Listening Task ◽  
Speech Tracking

AbstractSuccessful speech comprehension requires the listener to differentiate relevant from irrelevant sounds. Recent neurophysiological studies have typically addressed one of two candidate neural filter solutions for this problem: the selective neural tracking of speech in auditory cortex via the modulation of phase-locked cortical responses, or the suppression of irrelevant inputs via alpha power modulations in parieto-occipital cortex. However, empirical evidence on their relationship and direct relevance to behavior is scarce. Here, a large, age-varying sample (N=76, 39–70 years) underwent a challenging dichotic listening task. Irrespective of listeners’ age, measures of behavioral performance, neural speech tracking, and alpha power lateralization all increased in response to spatial-attention cues. Under most challenging conditions, individual listening success was predicted best by the synergistic interaction of these two distinct neural filter strategies. Trial-by-trial fluctuations of lateralized alpha power and ignored-speech tracking did not co-vary, which demonstrates two neurobiologically distinct filter mechanisms.

scholarly journals The impact of neural attentional filters on listening behavior in a large cohort of aging individuals

2020 ◽  
Author(s):  
Sarah Tune ◽  
Mohsen Alavash ◽  
Lorenz Fiedler ◽  
Jonas Obleser
Keyword(s):  
Behavioral Outcomes ◽  
Alpha Power ◽  
Neural Filter ◽  
Information Research ◽  
Listening Behavior ◽  
Neural Marker ◽  
Functional Relevance ◽  
Attentional Filter ◽  
The Impact ◽  
Speech Tracking

AbstractSuccessful listening crucially depends on intact attentional filters that separate relevant from irrelevant information. Research into their neurobiological implementation has focused on one of two auditory filter strategies: the lateralization of alpha power and selective neural speech tracking. However, the functional interplay of the two neural filter strategies and their potency to index listening success in an aging population remains unclear. Using electroencephalography and a dual-talker task in a representative sample of aging listeners (N=155; age=39–80 years), we here demonstrate an often-missed link from single-trial behavioral outcomes back to trial-by-trial changes in neural attentional filtering. First, we observed preserved attentional– cue-driven modulation of both neural filters across chronological age and hearing levels. Second, neural filter states varied independently of one another, demonstrating a functional trade-off between distinct neurobiological attentional filter mechanisms. Stronger neural speech tracking but not alpha lateralization boosted trial-to-trial behavioral performance. Our results highlight the translational potential of neural speech tracking as an individualized neural marker of adaptive listening behavior.Significance statementSuccessful listening requires a form of attentional filtering into behaviorally relevant and irrelevant acoustic information. Most previous studies have focused on one of two candidate neural filter strategies: the lateralization of alpha power and selective neural speech tracking. Closing the gap between hitherto separate lines of research, we used electroencephalography and a dual-talker task in a large sample of aging listeners to directly probe the functional relevance of state- and trait-level changes in these neural filter strategies to listening success. We demonstrate the co-existence of largely independent neural filters that establish alternating regimes of strong alpha lateralization versus neural speech tracking. Additionally, our results emphasize the utility of neural speech tracking over alpha lateralization as a potential neural marker of an individual’s adaptive listening behavior.

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