Contribution of Modified Visual Gain to Human Balance Control During Quiet, Upright Stance

Visual feedback provides critical information to support postural stability. Previous work has shown that magnifying visual feedback indirectly can improve postural control, such as by providing individuals with biofeedback during balance tasks. When studies have manipulated vision directly, the conditions have been restricted to include an absence of visual feedback and sway referenced paradigms. Therefore, this thesis aimed to understand how the gain of optic flow contributes to balance control during quiet, upright stance among healthy adults. Optic flow was amplified or reduced relative to head motion while participants stood quietly on either a firm or foam surface. Overall, when there was an increased reliance placed on the visual system by standing on foam, a tighter regulation of upright stance was observed as optic flow gain increased. Further, this thesis provided evidence that visual contributions to balance control may extend to higher frequencies of postural sway than previously theorized.