Progression of cognitive impairment in stroke patients

Abstract

To examine the progression of neuropsychological deficits in stroke patients with and without cognitive impairment. 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. 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. 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.