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

Abstract

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 was 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 exist, with less pathology in women.

Clinically accessible neuroimaging predictors of post-stroke neurocognitive disorder: a prospective observational study

“…The study protocol consisted of 3D-T1 weighted, axial T2, 3D-Fluid attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), and susceptibility-weighted imaging (SWI). Details about the MRI protocol have previously been described [ 20 ].…”

“…Findings were considered pathological where the mean MTA of both sides was ≥1.5 under the age of 75, a value ≥2 below the age of 85, and a value of ≥2.5 below 95 years, as recommended by Ferreira et al [ 31 ]. For a thorough description of the methods of visual assessment please see Schellhorn et al [ 20 ]. Please see Supplement A 4 for a description of the Fazekas scale, and MTA scale.…”