Multidomain cognitive dysfunction after minor stroke suggests generalized disruption of cognitive networks

Abstract

Objective: Although small strokes typically result in "good" functional outcomes, significant cognitive impairment can occur. This longitudinal study examined a cohort of patients with minor stroke to determine the pattern of deficits, evolution over time, and factors associated with outcome.

Methods: Patients admitted to the hospital with their first clinical minor stroke (NIH Stroke Scale [NIHSS] ≤ 10, absence of severe hemiparesis, aphasia, or neglect) were assessed at 1 month post-infarct, and a subset were followed over time (with 6- and 12-month evaluations). Composite scores at each time point were generated for global cognition, verbal memory, spatial memory, motor speed, processing speed, and executive function. Paired t-tests evaluated change in scores over time. Regression models identified factors associated with initial performance and better recovery.

Results: Eighty patients were enrolled, evaluated at 1 month, and prospectively followed. The average age of the participants was 62.3 years, and mean education was 13.5 years. The average stroke volume was 6.6 cc; mean NIHSS score was 2.8. At 1 month, cognitive scores were below the normative range and > 1 standard deviation below the patient's peak ("recovery") score for every cognitive domain, strongly suggesting that they were well below patients' prestroke baselines. Forty-eight patients followed up at 6 months, and 39 at 12 months. Nearly all (98%) patients significantly improved in global cognition (averaged across domains) between 1 and 6 months. Between 6 and 12 months, recovery was variable. Higher education, occupational class, and Caucasian race were associated with higher recovery scores for most domains.

Conclusions: Cognitive impairment across multiple domains is common following minor stroke regardless of infarct location, suggesting a global process such as network dysfunction that improves over 6 months. Degree of recovery can be predicted using baseline factors.

Keywords: cognition; dementia; minor stroke; outcomes; recovery.