Visually guided auditory attention in a dynamic 'cocktail-party' speech perception task: ERP evidence for age-related differences

Speech understanding in the presence of concurring sound is a major challenge especially for older persons. In particular, conversational turn-takings usually result in switch costs, as indicated by declined speech perception after changes in the relevant target talker. Here, we investigated whether visual cues indicating the future position of a target talker may reduce the costs of switching in younger and older adults. We employed a speech perception task, in which sequences of short words were simultaneously presented by three talkers, and analysed behavioural measures and event-related potentials (ERPs). Informative cues resulted in increased performance after a spatial change in target talker compared to uninformative cues, not indicating the future target position. Especially the older participants benefited from knowing the future target position in advance, indicated by reduced response times after informative cues. The ERP analysis revealed an overall reduced N2, and a reduced P3b to changes in the target talker location in older participants, suggesting reduced inhibitory control and context updating. On the other hand, a pronounced frontal late positive complex (f-LPC) to the informative cues indicated increased allocation of attentional resources to changes in target talker in the older group, in line with the decline-compensation hypothesis. Thus, knowing where to listen has the potential to compensate for age-related decline in attentional switching in a highly variable cocktail-party environment.