Abstract T MP46: Stroke-Related Neuroplasticity During Steering of Human Gait
Background: The risk of falling is higher in stroke survivors than among the general population. These falls are more frequent during walking and transfers or during turning. The neuronal substrates involved in steering of locomotion are poorly understood due to methodological limitations in quantifying brain activations during whole-body movements. Thus, no data is currently available to study the mechanisms of post-stroke brain plasticity for steering of gait. This study tested the hypothesis that stroke-induced neuroplastic changes for steering of gait can be quantified using 18F- fluorodesoxy-glucose (18F-FDG) Positron Emission Tomography (PET) in-vivo in humans Methods: PET imaging with 18F-FDG tracer was used to quantify cerebral glucose metabolism (CMRGlc) during two locomotor tasks (straight walking and turning) measured on separate days. Immediately prior to each walking task, a 5 mCi bolus of 18F-FDG was injected. Subjects walked for 40 minutes (duration of 18F-FDG uptake). Subjects were scanned on an ECAT HR+ scan (20min emission followed by 10min transmission) within 10 minutes of completing the walking task, well within reaching the 2h half-life of 18F. Images obtained during straight walking were subtracted from the ones acquired during steering Results: Subjects post-stroke showed an asymmetrical pattern of CMRGlc in sensorimotor areas and superior parietal lobule where the affected hemisphere shows no increase in CMRGlc. Differences between groups were also observed in the cerebellum where CMRGlc was increased in the vermis for controls, an area predominant for the control of trunk and gait. Stroke subjects, in contrast, showed increased CMRGlc in the hemishperes, associated with goal-directed leg movements. Conclusions: Neuroplasticity in complex locomotor tasks such as steering can be quantified using 18F-FDG PET in subjects post-stroke. This study showed that changes affect several brain regions remote to the infarct. Understanding stroke-related changes in brain activity during steering of locomotion is crucial for improving rehabilitative strategies to minimize falls and injuries in stroke survivors.