The Neurocognitive Basis of Age-Related Changes in Audiovisual Integration: Implications for Speech Perception and Fall Risk

Pepper, Jessica and Nuttall, Helen and Bampouras, Theodoros and Braithwaite, Jason J (2025) The Neurocognitive Basis of Age-Related Changes in Audiovisual Integration: Implications for Speech Perception and Fall Risk. PhD thesis, Lancaster University.

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Abstract

Multisensory integration is essential for the accurate perception of, and safe navigation through, our noisy, dynamic everyday environment. Evidence suggests that older adults exhibit increased, less accurate multisensory integration compared to younger adults, which can have a negative impact on activities of daily living such as speech perception and balance maintenance; the relationships between each of these concepts are explored in detail in Chapter 2. A greater understanding of the age-related changes in the bottom-up and topdown mechanisms of multisensory integration is key given our increasingly ageing population. As a result, Chapters 3-4 investigated the interplay between temporal precision and attentional control during audiovisual integration; the findings of these chapters suggested that the increased integration experienced by older adults could be attributed to weaker topdown attentional control and less modulated multisensory processing. The most comprehensive account of how multisensory processing changes with healthy ageing may therefore come from investigating the neural correlates of attentional control; Chapters 4-6 explore the functional role of alpha activity (8-12Hz) in the inhibition of task-irrelevant information, and whether reduced alpha activity in older adults could reflect their weaker attentional control during audiovisual and auditory processing. These chapters produced novel insights as to how patterns of alpha activity may change as a function of healthy ageing. Potential reasons for this are posited throughout; a recurring theme was the impact of heterogenous ageing trajectories on an older adult's ability to employ compensatory strategies, to preserve speech perception and balance performance. Taken together, this thesis has uncovered how age-related changes in the attentional modulation of sensory information may be reflected in alpha activity, and the impact of such changes on older adults' everyday speech perception and balance ability. The potential implications of this and directions for future research are discussed.