Vascular brain pathology is more important than neurodegeneration in pathogenesis of pre-stroke cognitive impairment

Introduction To better understand the development of post-stroke cognitive impairment,we explored the association between pre-stroke neuroimaging features and pre-stroke cognitive impairment and investigated possible gender differences. Few previous studies on this topic have been performed. Methods In this large prospective longitudinal multicenter brain-MRI cohort study, patients admitted to five stroke units at five different Norwegian hospitals were recruited as part of the Norwegian cognitive impairment after stroke study. Visual radiological assessment of small vessel disease and neurodegenerative changes were performed on brain MRI from 410 patients. Pre-stroke cognition was assessed using the Global Deterioration Scale. Results At least one pathological marker was found in 68% of the patients. The mean age (SD) of the patients with no pathological changes other than the acute stroke, was 70 (± 12.9) and 75 (± 10.2) years for those with pathological scans (p ≤ 0.001). Men were more likely to have at least one pathological brain MRI finding, lacunes, or pathological medial temporal lobe atrophy. The highest percentage of patients with a pathological pre-stroke GDS were found in the “cerebrovascular pathology” group (37.5%) and in the “mixed pathology”-group (44%). In these groups, both men and women had an increased risk of impaired pre-stroke cognition. Conclusion The majority of patients showed preexisting structural brain pathology. Cerebrovascular pathology was the dominating imaging finding associated with cognitive impairment, thus indicating that the pathogenesis of pre-stroke cognitive impairment might be driven more by small vessel disease (SVD) than neurodegenerative changes. Gender differences exists, with less pathology in women.