Baseline Function and Rehabilitation Are as Important as Stroke Severity as Long-term Predictors of Cognitive Performance Post-stroke

Abstract

Objective Although individuals with low stroke severity tend to recover well, cognitive impairment is common independent of stroke size or location. In this study, the patterns of recovery for individual cognitive domains and factors associated with outcome were examined. Design A prospectively enrolled cohort of patients with minor stroke was administered cognitive testing at 1, 6, and 12 mos postinfarct. Composite T scores were generated for global cognition and well as independent cognitive domains at each time point. Paired t tests compared changes in scores over time. Regression models identified factors associated with improvement. Results A total of 46 patients, with an average NIH Stroke Scale score of 2.7, were enrolled. Average age was 61.3 yrs. Patients improved overall between 1 and 6 mos; however, distinct patterns of recovery were seen for different cognitive domains. The most significant improvement was in spatial memory. Verbal memory scores remained low longitudinally. Motor speed and executive function increased, then plateaued. Despite a mean education of 13.6 yrs, only 36% of global cognition scores were higher than or equal to the normative mean at 12 mos, and only 57% of patients improved their global scores from 6 to 12 mos. Late recovery was associated with lower NIH Stroke Scale scores, higher 1-mo Montreal Cognitive Assessment scores, and rehabilitation. Baseline function predicted overall long-term recovery. Conclusion Patterns of recovery are distinct for individual cognitive domains for patients with minor stroke. Stroke severity and rehabilitation influence trajectory. Premorbid baseline predicts long-term outcome.