Multisensory integration precision is associated with better cognitive performance over time in older adults: A large-scale exploratory study.

Age-related sensory decline impacts cognitive performance and exposes individuals to a greater risk of cognitive decline. Integration across the senses also changes with age, yet the link between multisensory perception and cognitive ageing is poorly understood. We explored the relationship between multisensory integration and cognitive function in 2875 adults aged 50 + from The Irish Longitudinal Study on Ageing. Multisensory integration was assessed at several audio-visual temporal asynchronies using the Sound Induced Flash Illusion (SIFI). More precise integration (i.e. less illusion susceptibility with larger temporal asynchronies) was cross-sectionally associated with faster Choice Response Times and Colour Trail Task performance, and fewer errors on the Sustained Attention to Response Task. We then used k-means clustering to identify groups with different 10-year cognitive trajectories on measures available longitudinally; delayed recall, immediate recall and verbal fluency. Across measures, groups with consistently higher performance trajectories had more precise multisensory integration. These findings support broad links between multisensory integration and several cognitive measures, including processing speed, attention and memory, rather than association with any specific subdomain.