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UBC Theses and Dissertations

Characterizing visually evoked postural responses with a virtual reality head-mounted display in young and older adults Nielsen, Emma Iva

Abstract

Balance control requires the continuous integration of sensory information to maintain postural stability. Widely accessible virtual reality (VR) head-mounted display (HMD) technology can be used to directly manipulate stimuli presented to the visual system, and subsequent postural responses can then be characterized. This manipulation is of particular importance for older adults, who tend to have greater reliance on vision for balance control. However, at present visual cues in VR are substantially different to those in the real world. As such, previous real-world research investigating vision and postural stability cannot be assumed as directly transferrable to applications in VR using HMDs. Therefore, the purpose of this thesis was to characterize visually evoked postural responses (VEPRs) in VR using an HMD and examine how they varied across environmental conditions and populations of interest. In the first study of this thesis, a pseudorandom visual stimulus was presented to young adults in VR, with and without the postural threat of a virtually elevated surface height. Findings of evoked sway across experimental conditions demonstrated that young adults were visually sensitive to the stimulus. Despite pronounced psychological effects of the elevated surface height, postural threat did not influence VEPRs. The second study compared the presentation of real and virtual visual perturbations on VEPRs in young and older adults. Results indicated that within a given age group, comparable levels of sway were evoked in the two environments. In both real and virtual paradigms, older adults were more sensitive to visual stimuli than young adults. Evidence of sensory reweighting was observed as both groups were able to proportionally integrate balance-relevant visual cues based on the amplitude of the stimulus. Overall, this thesis provides an evidentiary basis for the utility of VR HMDs in future investigations of vision and balance, in young and older adults.

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Attribution-NonCommercial-NoDerivatives 4.0 International

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