Domain-specific cognitive impairment 6 months after stroke: the value of early cognitive screening

Abstract

ABSTRACTBackground/ObjectiveCognitive screening following stroke is widely recommended, yet few studies have investigated the prognostic value of acute domain-specific function for longer-term cognitive outcome. This study aimed to determine the prevalence of domain-specific impairment acutely and at 6 months, assess the proportion of change in cognitive performance, and examine the predictive value of acute domain-specific cognitive screening.MethodsA prospective cohort of consecutive stroke survivors completed the Oxford Cognitive Screen acutely (≤2 weeks) and 6 months post-stroke. Hierarchical multivariable regression analyses were used to predict general and domain-specific cognitive impairment at 6 months. Demographic/clinical covariates included age, sex, education, atrial fibrillation, hypertension, diabetes, smoking, stroke severity, lesion volume, recurrent stroke, and days to cognitive assessment.ResultsA total of 430 stroke survivors (mean age 73.9 years (12.5SD), 46.5% female, median NIHSS 5 [IQR 2-10]) completed 6-month follow-up. Impairments were prevalent within all domains at both timepoints, ranging from 26.7% (n=112) in praxis to 46.8% (n=183) in attention acutely, and 19.6% (n=79) in praxis to 32.6% (n=140) in language at 6 months. Proportion of recovery was highest in praxis (n=73, 71%) and lowest in language (n=89, 46%) and memory (n=82, 48%). Severity of 6-month cognitive impairment was best predicted by the addition of proportion of acute subtests impaired (adjustedR2=0.298,p<0.0001) over demographic/clinical factors alone (adjustedR2=0.105,p<0.0001). Acute cognitive function (β=0.403 SE 0.042,p<0.0001) was the strongest predictor of 6-month cognitive performance. Acute domain-specific impairments in memory (β=0.116 SE 0.027,p<0.0001), language (β=0.095 SE 0.027,p<0.0001) and praxis (β=0.086 SE 0.028,p<0.0001) were significant predictors of severity of cognitive impairment at follow-up.ConclusionCognitive impairment is highly prevalent initially after stroke across all domains, though impairments in language, memory and attention predominate at 6 months. Early domain-specific screening provides valuable prognostic information with respect to longer-term cognitive functioning.Key messagesWhat is already known on this topicSeveral demographic, stroke-related, vascular, and brain-related risk factors for post-stroke cognitive impairment have been identified, however, there is a lack of established early domain-specific cognitive markers of long-term cognitive outcome despite an emphasis on routine post-stroke cognitive screening.What this study addsThis study showed that severity of acute cognitive impairment identified through early domain-specific screening with the Oxford Cognitive Screen (OCS) was the strongest predictor of cognitive function at follow-up when compared to common post-stroke cognitive risk factors alone. Impairments in memory, language and praxis domains acutely after stroke were particularly important in predicting the severity of cognitive impairment at 6 months.How this study might affect research, practice, or policyThis study demonstrated for the first time that early domain-specific screening after stroke with the OCS provides valuable prognostic information with respect to long-term cognitive functioning. Each post-stroke cognitive profile is unique and therefore highlighting different strengths and weaknesses in performance early allows for more accurate information to be communicated to the patient, more tailored discharge care packages and appropriate allocation of rehabilitation resources.