Age-Related Changes to Multisensory Integration and Audiovisual Speech Perception

Abstract

Multisensory integration is essential for the quick and accurate perception of our environment, particularly in everyday tasks like speech perception. Research has highlighted the importance of investigating bottom-up and top-down contributions to multisensory integration and how these change as a function of ageing. Specifically, perceptual factors like the temporal binding window and cognitive factors like attention and inhibition appear to be fundamental in the integration of visual and auditory information—integration that may become less efficient as we age. These factors have been linked to brain areas like the superior temporal sulcus, with neural oscillations in the alpha-band frequency also being implicated in multisensory processing. Age-related changes in multisensory integration may have significant consequences for the well-being of our increasingly ageing population, affecting their ability to communicate with others and safely move through their environment; it is crucial that the evidence surrounding this subject continues to be carefully investigated. This review will discuss research into age-related changes in the perceptual and cognitive mechanisms of multisensory integration and the impact that these changes have on speech perception and fall risk. The role of oscillatory alpha activity is of particular interest, as it may be key in the modulation of multisensory integration.

A drift diffusion model analysis of age-related impact on multisensory decision-making processes

“…8 left ). Interestingly, our measure of tPoIE correlated positively with age suggesting a decrease (rather than increase, as is commonly hypothesised 69 , 70 ) in the effect of tPoIE on evidence accumulation with age. Given that multisensory benefits remained preserved when information became increasingly difficult to reconcile through AV preservations in drift rate and increases in decision boundary, we suggest that tPoIE decreases in likelihood to benefit multisensory integration across the adult lifespan in decisional speed, and is compounded by a compensatory mechanism in response caution that necessitates the need for additional complementary unisensory information to be accumulated to preserve choice accuracy.…”

“…Furthermore, they exhibit increased decision policy caution when faced with a decreased salience in stimulus properties, and therefore increased task difficulty, to preserve such benefits when decisional speed is compromised. Given older adults have been found to exhibit, for example, increased predispositions to fall 71 , as well as increased difficulty in audiovisual speech perception due to demands in processing dynamic cues 70 , 72 , our results demonstrate the importance of modelling age-related impact on multisensory decision-making behaviour. As such, we recommend further exploration to parse apart ageing effects on the precision of (multi)sensory stimulus representations and how they are modulated by difficulty in evidence consolidation, perhaps by (mis)matching difficulty levels across sensory modalities 2 .…”

Advances in Understanding the Phenomena and Processing in Audiovisual Speech Perception

“…With regard to how multisensory perception changes with age, Pepper and Nuttall [ 1 ] present a narrative review of findings from various experimental paradigms. They propose that changes that occur with aging in multisensory processing (including audiovisual speech) may be linked with balance control via similar mechanisms.…”