Cognitive performance and poor long-term functional outcome after young stroke

Objective: To investigate the influence of cognitive performance on long-term functional outcome after ischemic stroke (IS) in young adults aged 18 through 50 years (young IS). Methods: This study is part of a prospective cohort study among 277 stroke survivors with a young IS admitted to our department between January 1, 1980, and November 1, 2010. Functional outcome was assessed during follow-up between 2009 and 2012 with the modified Rankin Scale (mRS) and Instrumental Activities of Daily Living scale (IADL). Extensive neuropsychological investigation was performed. Logistic regression was used to calculate odds ratios (ORs) for a poor functional outcome (mRS.2 or IADL,8) for the 7 cognitive domains adjudicated for confounders. Cognitive function (continuous) as well as cognitive impairment (dichotomous) were studied. Results: Only decline in working memory (OR 0.3, 95% confidence interval [CI] 0.1-0.6) was associated with poor functional outcome on the mRS. Except for decline in processing speed (OR 0.5, 95% CI 0.3-0.8) and working memory (OR 0.4, 95% CI 0.2-0.7), no relation was found with poor functional outcome on IADL. Impairment in none of the individual cognitive domains was related to long-term functional outcome, although impairment in global cognitive function was related to a poor functional outcome on the IADL (OR 4.8, 95% CI 1.7-14.0). Conclusions: On average, 11 years after young IS there was no clear relationship between longterm cognitive deficits and long-term functional outcome or IADL, stressing the need for further prospective studies with further development of sensitive measures of functional prognosis.