Neural timescales of attention switching during speech listening

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Sara Carta¹ (cartas@tcd.ie), Emina Aličković^2,3, Johannes Zaar^2,4, Alejandro López Valdés¹, Giovanni Di Liberto¹; ¹Trinity College Dublin, ²Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark, ³Department of Electrical Engineering, Linköping University, Linköping, Sweden, ⁴Hearing Systems Section, Department of Health Technology, Technical University of Denmark, 18 Kgs. Lyngby, Denmark

Speech perception in the real-world often involves noisy scenarios with simultaneous speech streams. Previous research has shown that neural signals encode attended and ignored speech streams in a different manner, enabling the robust identification of the attended speaker from non-invasive electroencephalography (EEG) and magnetoencephalography signals. In naturalistic multi-talker scenarios, listeners can both sustain their attention to a particular speaker and also rapidly re-orient their focus of attention. Previous studies have examined speech attentional switching across spatially separated speakers and in the context of real-time attention decoding. However, the neural underpinnings of attentional switching remain to be understood. Our study investigated how attention switching unfolds across different stages of the speech processing hierarchy (envelope and word surprisal), addressing two central questions: 1) How rapidly can attention switching be detected from EEG signals? 2) How much longer does this mechanism take for more abstract linguistic features? EEG signals were recorded from twenty-four native English speakers who were instructed to switch attention between two spatially separated speech streams upon a visual cue. Using the multivariate Temporal Response Function and Canonical Component Analysis, we examined the timescales of the cortical tracking of acoustic and semantic information, as participants disengaged from one speech stream and engaged with the other. Our analyses indicate that redirecting attention during speech listening is underpinned by rapid envelope tracking dynamics, followed by a slower emergence of semantic processing, offering a novel insight into naturalistic speech listening dynamics.

Topic Area: ATTENTION: Auditory