Introduction: Chronic stroke may lead to persistent cognitive deficits in multiple domains. Despite this issue, there are no clear guidelines about post-stroke fitness to drive, due to a limited understanding of how stroke impairs brain networks essential for driving. We hypothesize reduced activity in driving-related brain regions, for more cognitively demanding tasks (e.g. left turns with traffic, distraction) and individuals with poorer neurocognitive test scores.
Methods: we tested 7 adults with prior ischemic stroke (44-71 yrs.) and imaged brain function using functional Magnetic Resonance Imaging (fMRI) while they performed simulated driving scenarios, using our novel MRI-compatible simulator system. Performance was compared to 10 healthy age-matched controls (56-75 yrs.).
Results: chronic stroke patients showed similar posterior brain activations as controls (e.g. visual and prefrontal lobes, precuneus). However, individuals with lower neurocognitive test scores (e.g. Montreal Cognitive Assessment, Trail-Making Test) had greater posterior activation during turning tasks, potentially due to increased cognitive effort. They also showed greater reductions in activity during distraction tasks, indicating brain function is more sensitive to distracting stimuli. Functional abnormalities were not proximal to infarcts, indicating non-focal alterations of brain networks following stroke.
Conclusions: This is the first demonstration of systematic changes in brain function for stroke patients, and relation to clinical measures. This may have implications in our understanding of how stroke affects brain function during integrative, real-world tasks.