EEG correlates of spatial shifts of attention in a dynamic multi-talker speech perception scenario in younger and older adults
•We explored EEG correlates of lateral shifts in auditory spatial attention.•N2ac and alpha power were increased immediately after switches in target speaker.•Increase in N2ac was related to a lesser post-switch decline in speech perception.•Increase in alpha lateralization was delayed relative to N...
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Veröffentlicht in: | Hearing research 2020-12, Vol.398, p.108077-108077, Article 108077 |
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Zusammenfassung: | •We explored EEG correlates of lateral shifts in auditory spatial attention.•N2ac and alpha power were increased immediately after switches in target speaker.•Increase in N2ac was related to a lesser post-switch decline in speech perception.•Increase in alpha lateralization was delayed relative to N2ac and alpha power.•N2ac and alpha lateralization to task-relevant stimulus was greater in young adults.
Speech perception under “cocktail-party” conditions critically depends on the focusing of attention toward the talker of interest. In dynamic auditory scenes, changes in talker settings require rapid shifts of attention, which is especially relevant when the position of a target talker switches from one location to another. Here, we explored electrophysiological correlates of shifts in spatial auditory attention, using a free-field speech perception task, in which sequences of short words (a company name, followed by a numeric value, e.g., “Bosch–6”) were presented in the participants’ left and right horizontal plane. Younger and older participants responded to the value of a pre-defined target company, while ignoring three simultaneously presented pairs of concurrent company names and values from different locations. All four stimulus pairs were spoken by different talkers, alternating from trial-to-trial. The location of the target company was within either the left or right hemisphere for a variable number of consecutive trials (between 3 and 42 trials) and then changed, switching from the left to the right hemispace or vice versa. Thus, when a switch occurred, the participants had to search for the new position of the target company among the concurrent streams of auditory information and re-focus their attention on the relevant location. As correlates of lateralized spatial auditory attention, the anterior contralateral N2 subcomponent (N2ac) and the posterior alpha power lateralization were analyzed in trials immediately before and after switches of the target location. Both measures were increased after switches, while only the increase in N2ac was related to better speech perception performance (i.e., a reduced post-switch decline in accuracy). While both age groups showed a similar pattern of switch-related attentional modulations, N2ac and alpha lateralization to the task-relevant stimulus (the target company's value) was overall greater in the younger, than older, group. The results suggest that N2ac and alpha lateralization reflect different atte |
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ISSN: | 0378-5955 1878-5891 |
DOI: | 10.1016/j.heares.2020.108077 |