Audiovisual Integration Delayed by Stimulus Onset Asynchrony Between Auditory and Visual Stimuli in Older Adults

Abstract

Although neuronal studies have shown that audiovisual integration is regulated by temporal factors, there is still little knowledge about the impact of temporal factors on audiovisual integration in older adults. To clarify how stimulus onset asynchrony (SOA) between auditory and visual stimuli modulates age-related audiovisual integration, 20 younger adults (21-24 years) and 20 older adults (61-80 years) were instructed to perform an auditory or visual stimuli discrimination experiment. The results showed that in younger adults, audiovisual integration was altered from an enhancement (AV, A ± 50 V) to a depression (A ± 150 V). In older adults, the alterative pattern was similar to that for younger adults with the expansion of SOA; however, older adults showed significantly delayed onset for the time-window-of-integration and peak latency in all conditions, which further demonstrated that audiovisual integration was delayed more severely with the expansion of SOA, especially in the peak latency for V-preceded-A conditions in older adults. Our study suggested that audiovisual facilitative integration occurs only within a certain SOA range (e.g., -50 to 50 ms) in both younger and older adults. Moreover, our results confirm that the response for older adults was slowed and provided empirical evidence that integration ability is much more sensitive to the temporal alignment of audiovisual stimuli in older adults.

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

“…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.…”

“…Aging may also affect the temporal characteristics of multisensory integration, which has important implications for other cognitive and motor functions . Converging evidence shows a widening of the temporal window of audiovisual integration, presumably due to the slower and more variable peripheral sensory processing . The widening of the window is a double‐edged sword: it can allow for unifying irrelevant events, thereby rendering it difficult to discriminate simultaneity, temporal order, and causal relationships among sensory stimuli, but it can also increase the possibility of integrating sensory events that might not have been integrated given the general age‐related slowing in sensory processing.…”

“…Converging evidence shows a widening of the temporal window of audiovisual integration, presumably due to the slower and more variable peripheral sensory processing . The widening of the window is a double‐edged sword: it can allow for unifying irrelevant events, thereby rendering it difficult to discriminate simultaneity, temporal order, and causal relationships among sensory stimuli, but it can also increase the possibility of integrating sensory events that might not have been integrated given the general age‐related slowing in sensory processing. The benefits and costs of the widened temporal window in old age, therefore, warrant further research so as to better understand its potential for ameliorating the common age‐related changes in sensory processing.…”

“…Several attempts have been made to elucidate the underlying cause of enhanced multisensory integration in healthy aging individuals . It has initially been hypothesized that the multisensory enhancement observed in old age might be a mechanism counteracting impaired unimodal processing or that it results from either the functional decline in the individual sensory systems, which could lead to increased multisensory benefit as predicted by the principle of inverse effectiveness or the widened temporal window of integration . More recent findings, however, suggest that the increased gains in older adults might reflect the age‐related differences in the amount of baseline sensory processing .…”

Increased Functional Brain Network Efficiency During Audiovisual Temporal Asynchrony Integration Task in Aging

“…Among multisensory integration modalities, the most typical is audiovisual integration in humans and animals, which has been represented in several previous studies ( Molholm et al, 2002 , 2006 ; Roach et al, 2006 ; Doehrmann and Naumer, 2008 ). Recently, our event-related potential (ERP) studies have indicated that audiovisual integration is regulated by temporal factors ( Yang et al, 2014 ; Ren et al, 2017b ). The temporal structure of auditory and visual stimuli can intervene in human audiovisual processing.…”