Visual Control of Adaptive Locomotion and Changes Due to Ageing

This chapter will review current theories of how adults use vision to guide adaptations to the basic locomotor rhythm in order to cope with environmental demands e.g. to step over an obstacle in our path, or to guide the foot to specific safe areas in the terrain, or to cope with the challenges to balance posed by descending stairs. A finding common to different gait adaptations is that they are usually, by necessity, programmed in advance to ensure stability and maximize efficiency. Thus visual cues are predominantly sampled and used in a feedforward or anticipatory manner to make gait adjustments. Recent evidence suggests that older adults, particularly those characterised as being at higher risk of tripping and falling, show changes in visuomotor control during adaptive locomotion and that the resulting changes to visual behaviour may be causally related to lower limb movement inaccuracies, compromised balance control and associated increased falls risk. The putative neural and biomechanical mechanisms underlying these changes will be discussed alongside the potential applications of current knowledge to falls prevention and rehabilitation in older adult populations.