The relationship between anxiety, gaze direction and increased falls risk in walking older adults

Older adults at a high-risk of falling tend to look away from a current stepping target in order to look at obstacles ahead. This early gaze transfer impairs the accuracy of stepping. It has previously been shown that this maladaptive gaze behaviour is associated with increased anxiety. This thesis aimed to elucidate the causal relationships between anxiety, sub-optimal gaze behaviour and increased falls risk in older adults. In separate experiments we manipulated experimental conditions to: 1) increase older participants anxiety via Social Evaluative Threat 2) reduce anxiety via relaxation exercises and 3) alter the extent to which participants previewed obstacles and walking goals via a gaze training intervention. Increasing older adults’ anxiety resulted in reduced stepping performance, and a measured reduction in anxiety was accompanied by increased stepping performance. There were few effects on eye movement timing characteristics suggesting that these changes in stepping behaviour were not mediated by altered gaze strategies. Route previewing intervention resulted in significant changes to older adults’ gaze behaviour, and improved self-confidence and stepping performance. These findings highlight the possibility of using interventions aimed at reducing anxiety and/or guiding gaze behaviour to address falls-risk in older adults

Reduced sensitivity for visual textures affects judgments of shape-from-shading and step climbing behaviour in older adults

Falls on stairs are a major hazard for older adults. Visual decline in normal aging can affect step climbing ability, altering gait and reducing toe clearance. Here we show that a loss of fine-grained visual information associated with age can affect the perception of surface undulations in patterned surfaces. We go on to show that such cues affect the limb trajectories of young adults, but due to their lack of sensitivity, not that of older adults. Interestingly neither the perceived height of a step nor conscious awareness are altered by our visual manipulation but stepping behaviour is: suggesting that the influence of shape perception on stepping behaviour is via the unconscious, action-centred, dorsal visual pathway