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Category: Project

Description: Ageing is thought to bring about increased multisensory integration. Evidence for this comes from the Sound-Induced Flash Illusion (SIFI; Shams et al 2000), in which presenting a single visual flash with two auditory beeps results in the perception of two visual flashes (even though only one occurred). Older adults appear more susceptible to this illusion, and continue to be susceptible even when the flash and beeps are separated in time. It has been suggested that this “over integration” in older adults may serve an adaptive purpose, compensating for unisensory decline (Laurienti et al 2006). As such, a recent review highlighted the need to consider the role of unisensory deterioration on multisensory processing in ageing (Brooks et al 2018). Data available from The Irish Longitudinal Study of Ageing (TILDA) now provides the opportunity to examine the extent to which vision and hearing ability in older adults relate to differences in multisensory processing. For a large proportion of subjects, unisensory data are also available from two time points, separated by 4 years. Thus we are able to examine multisensory processing in relation to current sensory performance as well as decline over 4 years. Using structural equation modelling (SEM), we will assess whether unisensory ability, and change in ability, is related to multisensory integration. Multisensory integration will be measured through SIFI susceptibility (i.e. illusions produced through incongruent audio-visual input) and multisensory gains (i.e. accuracy increases gained through congruent audio-visual input). The research questions this project will address are: 1) Is the effect of ageing on SIFI susceptibility and multisensory gain moderated by unisensory function, and the relative reliability of vision and audition, at the time of testing? 2) Is the effect of ageing on SIFI susceptibility and multisensory gain moderated by the extent of 4-year change in unisensory function, and relative reliability of vision and hearing? 3) Are those that experience higher multisensory gains also more likely to be susceptible to the SIFI?