Individuals with normal hearing exhibit considerable variability in their capacity to understand speech in noisy environments. Previous research suggests the cause of this variance may be due to individual differences in cognition and auditory perception. To investigate the impact of cognitive and perceptual differences on speech comprehension, 25 adult human participants with normal hearing completed numerous cognitive and psychoacoustic tasks including the Flanker, Stroop, Trail Making, reading span, and temporal fine structure tests. They also completed a continuous multitalker spatial attention task while neural activity was recorded using electroencephalography. The auditory cortical N1 response was extracted as a measure of neural speech encoding during continuous speech listening using an engineered "chirped-speech" (Cheech) stimulus. We compared N1 component morphologies of target and masker speech stimuli to assess neural correlates of attentional gains while listening to concurrently played short story narratives. Performance on cognitive and psychoacoustic tasks was used to predict N1 component amplitude differences between attended and unattended speech using multiple regression. Results show inhibitory control and working memory abilities can predict N1 amplitude differences between the target and masker stories. Interestingly, none of the cognitive and psychoacoustic predictors correlated with behavioral speech-in-noise listening performance in the attention task, suggesting that neural measures may capture different aspects of cognitive and auditory processing compared with behavioral measures alone.
Keywords: N1 component; auditory attention; auditory processing; cognition; event-related potential; speech-in-noise.
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