350 INTEGRATION OF VISION AND HEARING IS ASSOCIATED WITH GAIT VELOCITY IN A LARGE SAMPLE OF MIDDLE-AGED AND OLDER ADULTS

Abstract

Abstract Background Multisensory integration is the ability to appropriately merge information from several senses for the purpose of perceiving and acting in the environment. Its importance for higher level cognition and function has emerged in recent years. Walking requires to combine information from multiple senses to coordinate effective movements. In this study, we tested the association between a well characterised multisensory task, the Sound-Induced Flash Illusion (SIFI), and gait velocity in 3,255 participants from The Irish Longitudinal Study on Ageing. The SIFI is the illusory perception of two flashes when one flash is presented with two beeps. We hypothesised that high SIFI susceptibility would be associated with slower gait velocity Methods Gait was measured under three conditions; usual pace, cognitive dual tasking, and maximal walking speed. A separate logistic mixed effects regression was run for: (1) gait at usual pace, (2) change in gait speed for the cognitive dual-task relative to usual pace, and (3) change in maximal walking speed relative to usual pace. The model controlled for covariates including age, sex, education, vision and hearing abilities, Body Mass Index, and cognitive function. Results Slower gait was associated with more illusions, indicating that those who integrated incongruent sensory inputs over longer intervals, also walked slower. Relative change for cognitive dual tasking and maximal walking speed were also significantly associated with SIFI at longer SOAs. Conclusion These findings extend growing evidence showing that mobility is associated with multisensory processing in ageing; in particular, the mechanisms appear related to the temporal dynamics of sensory integration.