Stimulus Specific to Age-Related Audio-Visual Integration in Discrimination Tasks

Abstract

Age-related audio-visual integration (AVI) has been investigated extensively; however, AVI ability is either enhanced or reduced with ageing, and this matter is still controversial because of the lack of systematic investigations. To remove possible variates, 26 older adults and 26 younger adults were recruited to conduct meaningless and semantic audio-visual discrimination tasks to assess the ageing effect of AVI systematically. The results for the mean response times showed a significantly faster response to the audio-visual (AV) target than that to the auditory (A) or visual (V) target and a significantly faster response to all targets by the younger adults than that by the older adults (A, V, and AV) in all conditions. In addition, a further comparison of the differences between the probability of audio-visual cumulative distributive functions (CDFs) and race model CDFs showed delayed AVI effects and a longer time window for AVI in older adults than that in younger adults in all conditions. The AVI effect was lower in older adults than that in younger adults during simple meaningless image discrimination (63.0 ms vs. 108.8 ms), but the findings were inverse during semantic image discrimination (310.3 ms vs. 127.2 ms). In addition, there was no significant difference between older and younger adults during semantic character discrimination (98.1 ms vs. 117.2 ms). These results suggested that AVI ability was impaired in older adults, but a compensatory mechanism was established for processing sematic audio-visual stimuli.

Sustained Auditory Attentional Load Decreases Audiovisual Integration in Older and Younger Adults

“…Therefore, another possible reason for the reduced AVI in older adults might also be attributed to the decline in attention. AVI was delayed in the older adults relative to the younger adults in all attentional load conditions, and this result was consistent with previous studies [12,33,39]. Responses of older adults were shown to be slower than those of younger adults in many cognitive tasks [61,62], and there was a general functional decline with aging [63,64].…”

“…In addition to attentional load, aging is also an important factor that alters an individual's perception of auditory information and visual information and includes decreased visual sensitivity [31] and increased auditory thresholds [32]. Studies examining age-related AVI showed that the AVI was lower or higher in older adults than in younger adults and was task and stimulus dependent [33,34]. Ren et al first studied the influence of visual attentional load on AVI and found lower AVI in older adults than in younger adults under all visual attentional load conditions at the behavioral level [12].…”

Visual Perceptual Load Attenuates Age-Related Audiovisual Integration in an Audiovisual Discrimination Task

“…However, the current studies could not identify whether the higher AVI is an adaptive mechanism or an indicator for unisensory decline, and future neuroimaging studies are necessary to clarify this matter. In addition, the AVI was significantly delayed in older adults compared with younger adults under all visual perceptual-load conditions, which was consistent with previous studies ( Ren et al, 2018 , 2020b ). According to the “time-window-of-integration model” proposed by Diederich et al (2008) before the integration of auditory and visual information (second stage), it is necessary to complete early auditory and visual information processing, which was assumed to be independent (first stage).…”

“…Additionally, aging is an important factor that influences AVI, and some researchers reported that the AVI was higher for older adults than for younger adults ( Laurienti et al, 2006 ; Peiffer et al, 2007 ; Stephen et al, 2010 ; Ren et al, 2020b ), but how AVI changed with the alteration of visual perceptual load for older adults is also still unclear. Recently, some of them proposed that higher AVI in older adults is an adaptive mechanism to compensate for unimodal sensory decline ( Laurienti et al, 2006 ; Peiffer et al, 2007 ; Freiherr et al, 2013 ; Ren et al, 2020c ), and the audiovisual perceptual training could improve cognitive function of healthy older adults ( Anguera et al, 2013 ; Yang et al, 2018 ; O’Brien et al, 2020 ) and patients with mild cognitive impairment ( Lee et al, 2020 ).…”

Sustained visual attentional load modulates audiovisual integration in older and younger adults

“…In contrast, some studies have reported that as a compensatory mechanism, AVI is higher in older adults than in younger adults (Diederich, Colonius, & Schomburg, 2008;Laurienti, Burdette, Maldjian, & Wallace, 2006;Peiffer, Mozolic, Hugenschmidt, & Laurienti, 2007). A contrary conclusion was obtained by other studies (Mahoney, Li, Oh-Park, Verghese, & Holtzer, 2011;Stephen, Knoefel, Adair, Hart, & Aine, 2010;Tye-Murray, Sommers, Spehar, Myerson, & Hale, 2010); this discrepancy mainly resulted from differences in experimental materials, study paradigms, and analysis methods (Ren, Xu, Lu, Wang, & Yang, 2020;Yang, Li, Li, Guo, & Ren, 2020). Using the same experimental materials, study paradigms, and analysis methods, investigated the difference in AVI between older and younger adults Ren, Li, et al, 2020) and the difference in AVI under visual (Ren, Li, et al, 2020) and auditory (Ren, Li, et al, 2020) transient attentional load conditions.…”