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Background and Purpose: The understanding of the contribution of genetic factors to cognitive impairment after stroke is incomplete. The aim of the study was to examine whether the apolipoprotein E ε4 allele (ApoE ε4) is a risk factor for cognitive impairment in the early phase after stroke. Methods: The sample comprised 152 Norwegian stroke rehabilitation inpatients (mean age 76.8 years, SD 10.5) examined at a mean of 18.3 days (SD 13.4) after hospital admission. Post-stroke cognitive impairment was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The following proposed risk factors were analysed: ApoE genotype, demographics (age, sex, education), pre-stroke cognitive reduction [Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)], pre-stroke vascular factors (including previous stroke), stroke characteristics (type, location), and neurological stroke-related impairment [National Institutes of Health Stroke Scale (NIHSS)]. Cognitive impairment was defined as an RBANS total index score ≤1.5 SD below the mean. Multiple logistic regression analyses were performed to find risk factors for post-stroke cognitive impairment. Results: Four variables were found to be independent risk factors for cognitive impairment after stroke: ApoE ε4 (OR = 3.7; 95% CI = 1.2–11.6), IQCODE score ≥3.44 (OR = 9.2; 95% = CI 2.3–37.2), total or partial anterior stroke syndromes (OR = 3.2; 95% CI = 1.3–8.0), and NIHSS total score >5 (OR = 7.3; 95% CI = 2.7–19.7). No association between ApoE ε4 and pre-stroke cognitive reduction (IQCODE) was found. Conclusions: The presence of one or two ApoE ε4 alleles may be a significant independent risk factor for cognitive impairment in the early phase after stroke.

Objective To examine the relationship between the ApoE e4 allele and cognitive impairment 13 months after stroke. Methods One hundred four stroke rehabilitation patients were cognitively tested on average 18 days after hospital admission and again 13 months later with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The following potential risk factors for post-stroke cognitive impairment (defined by a RBANS total index score below 77.5 points) at 13 months follow-up were analyzed in bivariate and logistic regression analyses: ApoE-genotype, socio-demographic variables, pre-stroke cognitive reduction (The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)), vascular factors, lesion characteristics, and neurological impairment (The National Institute of Health Stroke Scale (NIHSS)). Differences in general cognitive performance (pre-stroke, baseline, and follow-up) across patients with different ApoE-genotypes were analyzed, and lastly differences between e4-carriers and non-carriers for changes in performance in various cognitive domains over the 13 months period were examined. Results Significant risk factors for cognitive impairment at 13 months were ApoE e4, pre-stroke cognitive reduction (IQCODE 3.44+), previous stroke, and neurological impairment (NIHSS Total Score >5). A significant dose-dependent effect of the ApoE-genotype in relation to overall post-stroke cognitive functioning was found at baseline and follow-up, but not pre-stroke. The e4 carriers showed a significant decline in tests related to verbal learning and memory compared to the non-carriers. Conclusions The ApoE e4-allele constitutes an independent risk factor for cognitive impairment at 13 months post-stroke, and is associated with progression of cognitive decline in tasks related to verbal learning and memory. Copyright © 2009 John Wiley & Sons, Ltd.