Cognitive resilience at 3 years after stroke depends on pre‐ and post‐stroke factors

Abstract

AbstractBackgroundThe incidence of dementia in stroke survivors is greater than in stroke‐free people. However, some stroke survivors show cognitive resilience, withstanding the detrimental effects of stroke. In this study, we explored the differences between cognitively‐impaired (CI) and cognitively‐normal (CN) survivors in comparison with healthy controls (HC).MethodParticipants were sampled from the Cognition And Neocortical Volume After Stroke (CANVAS) study. Sociodemographic, clinical, neuropsychological, cognitive, neuroimaging, sleep, and physical activity data were obtained for 93 stroke participants at 3‐months and 3‐years post‐stroke and for 35 HC at equivalent timepoints. Stroke participants were classified as CN (n = 71) or CI (n = 22) at 3‐years based on mood scores, clinical interviews, and z‐scores of performance in five cognitive domains: attention, memory, language, executive and visuospatial functions. Structural brain volumes were estimated from T1‐weighted MRI using longitudinal FreeSurfer segmentation. Linear random‐intercept mixed‐effects modelling was used to compare between groups and timepoints accounting for differences in age, sex, years‐of‐education, and total‐intracranial volume.ResultThe stroke group overall had higher incidence of atrial fibrillation, scored higher on anxiety and depression, and had lower sleep efficiency compared to HC. Stroke survivors had thinner cortex, less cerebellar grey‐matter (GM), and larger choroid plexuses, and greater enlargement of the ventricles, at both timepoints. The CI survivors had more comorbidities, were older, were less active at both timepoints, and had lower years‐of‐education compared to both CN survivors and HC. They had more vascular risk factors and APOE‐ε4 allele carriage status compared to controls.Only the CI group showed deficits in ipsilesional cortical GM, hippocampal and thalamic volumes, and reduced total brain volume at 3‐months compared to controls. The CI survivors had larger stroke lesions compared to CN survivors and showed a greater increase in white matter hyperintensities between timepoints.At 3 months in CN survivors, cognitive performance in assessed domains was significantly lower, except for language. While performance in the CN survivors improved over time especially in language and visuospatial function, cognitive scores remained lower in the CI survivors, with a decline in memory scores.ConclusionPost‐stroke cognitive resilience appears dependent on clinical, sociodemographic, and neuroimaging factors, which assist in post‐stroke prognostication.