Grant: Travel Awards - Institute Community Support

Turning while walking is a difficult task for individuals with Parkinson's disease increasing the risk for falls and injury. One reason for this mobility impairment is thought to be an inability to recruit normal brain networks in challenging walking conditions. As a first step to provide adequate treatment of these mobility impairments, this project described brain activity in individuals with Parkinson's disease during turning compared to healthy older adults. Healthy older adults and older adults with Parkinson's Disease without cognitive impairment performed turning and straight walking. Cerebral glucose metabolism, a marker of brain activity, was measured using positron emission tomography (PET). In the turning task, participants navigated a continuous trajectory turning around colored markers, whereas in the straight walking task, participants walked straight in the center of 28 m walking lanes. Step length and step symmetry were measured using an inertial-based sensor system. During turning, older adults had increased activity in a frontoparietal network involved in cognitive control (the superior parietal lobule, superior frontal gyrus, caudate, and middle occipital gyrus) and the cerebellum. Individuals with Parkinson's Disease subjects had reduced activity in the frontoparietal network, and increased activity of occipital regions. Both groups had increased activity of the supplementary motor area for straight walking as compared to turning, which was increased in healthy older adults. Step length variability and step asymmetry during steering was greater in Parkinson's Disease In Parkinson's Disease there is reduced activity within the executive cortical basal ganglia circuity involved in normal control of complex walking. These results suggest that there is an inability to recruit normal brain circuits for complex walking and may represent an alternate neural mechanism used to compensate for turning impairments in Parkinson's Disease.