Grant: Travel Awards - Institute Community Support

Steering of gait or turning while walking is a challenging task that can be hindered by sensorimotor and gait abnormalities that arise in healthy aging. These age-related impairments tend to accelerate after middle-age (>65) and can lead to turning difficulties and falls. At present, the control of walking at the level of the brain and changes that occur in middle-age are poorly understood. Therefore, the aim of this study was to use a brain imaging technique to compare brain activations during steering of gait to straight walking in healthy young adults and determine if these activations modulate in middle-age. Therefore, Seven young (age range: 20-28) and five middle-aged (55-63) healthy adults completed steering of gait (SG) and straight walking (SW) tasks. In the SW task, participants walked in the centre of a walking lane (1.5 m by 32 m), whereas in the SG task, participants followed a curved path around coloured cones. Prior to each task, a radiolabelled glucose analogue was injected to track glucose metabolism in the brain. After injection, each task was performed continuously for 40 minutes followed by positron emission tomography (PET) brain image acquisition. Movement outcomes (i.e., walking speed and number of errors) were obtained via video-based analysis. Results showed the same activations in parietal areas during SG for both groups, but a laterality index revealed that middle-aged subjects had a more asymmetric activation pattern than their young counterparts. Movement analysis showed that both groups walked slower during SG as compared to SW, and no significant differences in errors across groups were observed. These findings provide the first quantification of brain activity during real steering of gait in healthy subjects and show that parietal areas play an important role in steering of gait. Further, results suggest that a modulation of activation pattern arises in middle-age that may be related to subclinical sensorimotor and gait impairments.