Investigating the spatial and temporal modulation of visuotactile interactions in older adults

Abstract

Previous research has shown that spatially and temporally disparate multisensory events are more likely to interact for older adults. For visuotactile interactions, this suggests that the representation of peripersonal space is expanded and temporal perception within this space is less precise. Previously, visuotactile space has been found to expand horizontally into the opposite hemispace, and here we sought to replicate and extend this by exploring both horizontal and vertical space from the hand. Moreover, we investigated whether both spatial and temporal domains are affected for an individual, which have previously been measured using distinct tasks and different participants. We presented a modified cross-modal congruency task (Poole et al. in Multisens Res. doi: 10.1163/22134808-00002475 , 2015a) to thirty older participants (age range 65-85 years), with unisensory tactile performance equated for each individual. For the temporal manipulation, the timings of visual distractors and tactile targets were offset. For the spatial manipulation, visual distractors were presented from multiple positions in ipsilateral and contralateral hemispaces. Whilst the temporal modulation of visuotactile interactions for older adults was equivalent to that observed in young adults, spatial modulation was reduced; significant visuotactile interactions were observed for visual distractors presented in the same and opposite hemispace to the stimulated hand, in the lower visual field. This suggests an expanded representation of visuotactile space surrounding the hand in older adults, which occurs horizontally into the contralateral hemispace only, rather than expanding both vertically and horizontally. This is likely to have consequences for perception of space and goal-directed action in ageing.

“Walking” through the sensory, cognitive, and temporal degradations of healthy aging

“…Given the age‐related alterations in sensory and cognitive processing, one would also expect aging to be associated with major declines in multisensory perception. Yet, studies have shown that although older adults exhibit in general worse performance as compared to their young counterparts (e.g., slower reaction times), they show greater multisensory gains for different sensory combinations, including audiovisual, visual‐somatosensory, and audio‐somatosensory stimulus pairs . The greater multisensory gains observed in older adults have been replicated in paradigms differing in terms of their attentional demands and the tasks employed, such as simple reaction, discrimination, saccadic reaction time, and temporal perception tasks, thus pointing to a robust age‐dependent facilitative effect of multisensory processing on behavioral performance.…”

“…The multisensory enhancements observed in healthy aging also entail older adults’ inclination to integrate all information available due to the wider temporal windows of integration and the inefficient weighting of sensory inputs. This tendency has been found to affect performance when part of the sensory information needs to be ignored (e.g., irrelevant information) and has been systematically linked to age‐related deviations from normal balance and gait, increased susceptibility to audiovisual illusions (i.e., decreased accuracy), poorer spatial working memory and poorer functional mobility, and altered decision making when inferring event causality . For example, fall‐prone older adults exhibit a wider window of integration and increased susceptibility (i.e., decreased accuracy) to audiovisual illusions as compared to those with no history of falling .…”

“…Multisensory processing can ameliorate the issues associated with the age‐related decline in individual sensory systems and counteract the negative effects of cognitive aging, including the general slowing of cognitive processing and the deficits in executive control, working memory, and allocation of attentional resources, and also facilitate older adults’ movement timing and improve their postural control . The larger multisensory gains reported in the elderly can be exploited by exposing older adults to multisensory rather than unimodal stimulation of a given event, which has an inherently high potential in improving older adults’ sensory, cognitive, temporal, and motor processing . Multisensory processing strategies can assist the elderly to use information from several modalities (e.g., vestibular or auditory information) rather than the visual modality alone .…”

Using Race Model Violation to Explore Multisensory Responses in Older Adults: Enhanced Multisensory Integration or Slower Unisensory Processing?

“…Stevenson and colleagues (2012) have also shown individual differences in MSI in non-RT based measures, even in a relatively more homogenous young adult group. Recent experiments within our lab have attempted to reduce this within and between group variability by initially constraining individual unisensory performance, thus enabling the influence of multisensory stimulation to be more easily observed (Poole et al, 2015a(Poole et al, , 2015bCouth, Gowen and Poliakoff, 2016). Similarly, there are other studies which have used different experimental approaches and models of multisensory processing which have demonstrated age-related differences, such as differences in sensory (re)weighting using (e.g.…”

“…vision) when the task requires participants to attend to-and make a judgement about-a single modality (e.g. touch), and so information from different sensory modalities may be more readily combined (Poliakoff, Ashworth, et al, 2006;Poliakoff, Shore, et al, 2006;Couth, Gowen and Poliakoff, 2016). Whichever the explanation, it has been demonstrated that older adults show enhanced integration even in a simple reaction time task (Peiffer et al, 2007), thus it seems likely that this effect emerges early at the level of signal detection, prior to any higher-level processes which may be affected by general cognitive slowing in ageing (cf.…”