Conscious movement processing, fall-related anxiety, and the visuomotor control of locomotion in older adults

Abstract

Objectives. Older adults anxious about falling will often consciously process walking movements in an attempt to avoid falling. They also fixate their gaze on the present step rather than looking ahead to plan future actions. The present work examined whether conscious movement strategies result in such restricted visual planning. Methods. Eighteen community-dwelling older adults (agemean=71.22; SD=5.75) walked along a path and stepped into two raised targets. Repeated-measures ANOVAs were used to compare gaze behaviour and movement kinematics when participants walked: (a) at baseline (ground level); (b) under conditions designed to induce fall-related anxiety (walkway elevated 0.6m); and (c) in the absence of anxiety (ground level), but with explicit instructions to consciously process movements. Results. Participants reported increased conscious movement processing when walking both on the elevated walkway (fall-related anxiety condition) and at ground level when instructed to consciously process gait. During both conditions, participants altered their gaze behaviour, visually prioritising the immediate walkway 1-2 steps ahead (areas needed for the on-line visual control of individual steps) at the expense of previewing distal areas of the walking path required to plan future steps. These alterations were accompanied by significantly slower gait and increased stance durations prior to target steps. Conclusions. Consciously processing movement (in the relative absence of anxiety) resulted in gaze behaviour comparable to that observed during conditions of fall-related anxiety. As anxious participants also self-reported directing greater attention towards movement, this suggests that fall-related anxiety may disrupt the visual control of gait through increased conscious movement processing.