Age-related changes in sustained visual attentional modulation of audiovisual integration

Audiovisual integration (AVI) depends on dynamic interactions between multisensory neural systems and attentional processes. However, it remains unclear how sustained attentional demands modulate this interaction, particularly in aging, where declines in sensory processing and attentional capacity may alter the efficiency of these neural mechanisms. Here, 23 younger adults and 22 older adults completed a dual-task paradigm combining an audiovisual discrimination task (to assess AVI) with a multiple object tracking task (to manipulate sustained attentional load). Results revealed that younger adults exhibited an inverted U-shaped pattern of early AVI across load levels, with integration peaking under medium attentional load and diminishing under both low-load and high-load conditions. In contrast, older adults showed greater AVI under low-load and medium-load conditions relative to high load. Notably, older adults demonstrated enhanced AVI during the late integration window (420-460 ms) compared with younger adults. ERP analyses further indicated delayed onsets of both early and intermediate AVI components in older adults, suggesting age-related alterations in the temporal dynamics of multisensory processing. These findings suggest that neural plasticity and compensatory mechanisms may support AVI under sustained attentional demands in aging, highlighting the role of cognitive resources in shaping multisensory processing. OPEN PRACTICES STATEMENT: The experiments reported in this article were not preregistered. The stimulus materials and de-identified data supporting the findings of this study are available from the corresponding author upon reasonable request.