Optometry and Vision Sciences - Theses
Permanent URI for this collection
Search Results
1 - 1 of 1
-
ItemAudiovisual synchrony perception in older adults( 2015)The purpose of this project was to examine differences in the behavioural and neural measures of audiovisual synchrony perception between younger and older adults. To accurately perceive events in the natural scene, the human perceptual system needs to combine related and segregate unrelated auditory and visual stimuli. The amount of temporal asynchrony is one of the key properties that define whether an auditory and a visual stimulus are related, and whether they should be perceived as originating from the same event. As older adults experience reduced visual contrast and hearing sensitivities, this project investigated audiovisual synchrony perception in older adults after scaling stimulus levels to individual detection thresholds. It was also investigated if older adults are able to realign their perception of audiovisual synchrony after adapting to asynchrony - an ability that is potentially important for correctly perceiving audiovisual pairs across distance. Additionally, this project investigated the impact of older age on the underlying neural time course for audiovisual synchrony perception. The results from this project demonstrated that older adults were less sensitive to audiovisual asynchrony even after scaling the stimuli to their own detection thresholds for visual contrast and sound intensity. Older adults also adapted less to sound-lag asynchrony adaptation as compared to the younger adults. In addition, older adults showed additional neural activity in the frontal and parietal regions in order to form perceptual decisions for audiovisual synchrony. The findings from this project could imply that older adults find it more difficult to correctly perceive related audiovisual events in a natural scene, particularly for distant events. The additional involvement of the frontal and parietal areas in older adults may indicate that they may compensate by recruiting extra neural resources to perform the same perceptual task as younger observers. This project also considered some future work that are required to understand the real-life implications of older age on audiovisual synchrony perception like the effect of spatial clutter (i.e. in crowds) and the effect of rapid adaptation. As a whole, the findings from this project added knowledge to the body of work of ageing on audiovisual synchrony perception.