Progression of cognitive impairment in stroke patients

Objective: To examine the progression of neuropsychological deficits in stroke patients with and without cognitive impairment. Methods: The authors assessed the Sydney Stroke Study cohort 1 year after index assessment with detailed neuropsychological and medical-psychiatric assessments. The neuropsychological tests were classified into cognitive domains, and composite z-scores adjusted for age and education. Changes in cognitive test scores were compared between groups and predictors of cognitive change examined. Results: Patients (n = 128) had a mean decline of 0.83 (SD 2.2) points on the Mini-Mental State Examination (MMSE) compared to an increase of 0.76 (1.3) in controls (n = 78) (p < 0.0001), and a small but significant decline in informant ratings of function and cognition. The decline on a composite index of cognitive function was not significantly different in the groups after correction for age, education, and index assessment cognitive function. Stroke/transient ischemic attack patients, however, had greater decline in verbal memory and visuoconstructive function. The occurrence of an interval stroke (n = 14) significantly increased the cognitive decline to a mean 2.0 points on the MMSE. The rate of change had a significant correlation (r = 0.24) with white matter hyperintensity volume at index assessment. On regression analysis the only predictor of cognitive change was years of education, which had a protective function. Conclusions: Subjects with cerebrovascular disease have a slow decline in cognitive functioning in the absence of further cerebrovascular events, although the occurrence of such an event accentuates the dysfunction. Education plays a protective role.