351 Integration of Auditory and Visual Information is Associated with Ageing, Sex and Cognitive Performance

Background In ageing, multisensory integration, i.e. the ability to combine efficiently information from different sensory modalities, is emerging as a stand-alone contributor to explaining cognitive and functional deficits. Experimental evidence shows that inefficient multisensory integration is associated with cognitive impairment, falls and balance maintenance; however these findings need to be supported by large population representative studies. We utilised the Sound-induced flash illusion (SIFI) as test of multisensory efficiency; the test was conducted on a population representative sample from the Irish Longitudinal Study on Ageing (TILDA). We hypothesized that Susceptibility to the SIFI would increase with ageing and would be associated with poorer Montreal Cognitive Assessment (MoCA) scores. Methods Participants: 3,955 adults aged 50 years and over. Participants provided informed consent. Data were drawn from the third wave of the TILDA study, in which participants took part in a Computer Assisted Interview and a Health Assessment. The SIFI test was part of the Health Assessment; SIFI is a computer-based test in which participants see a series of white dots appearing quickly on the screen, which participants are required to count; the dots (flashes) can be paired with 0, 1 or 2 beeps; when one dot is paired with two beeps, there is the illusory perception that two dots are presented. A hierarchical Bayesian, ordinal-regression model was used to determine which variables predicted audio-visual integration (SIFI proportion of correct responses, i.e. no illusions). We controlled for a range of covariates. Results As predicted, higher susceptibility to the SIFI, indicating higher integration of audio-visual information, was associated with older age, and poorer scores at MoCA. Female sex was also associated with higher susceptibility, which represents a novel result in the literature. Conclusion The present study presents the first findings on multisensory integration in a large population representative study. They confirm that inefficient integration is associated with ageing, poorer cognition and, unexpectedly, being female.