Highly educated people face steeper mental declines after stroke

Stroke survivors who have attended some level of higher education may face even steeper mental declines, according to a study led by Michigan Medicine.

In an analysis of cognitive outcomes for more than 2,000 patients seen for stroke between 1971 and 2019, college graduates performed better on initial post-stroke examinations of global cognition, a measure of overall cognitive ability that includes mental functions like memory, attention and processing speed.

However, stroke survivors who attended any level of higher education had faster declines in executive functioning -- skills used to manage everyday tasks, such as working memory and problem solving -- compared to patients with less than a high school degree.

"Brain atrophy occurs over time regardless of education level," said Mellanie V. Springer, M.D., M.S., first author and Thomas H and Susan C Brown Early Career Professor of Neurology at University of Michigan Medical School.

"Our findings suggest that attending higher education may enable people to retain greater cognitive ability until a critical threshold of brain injury is reached after a stroke. At this point, compensation may fail, and rapid cognitive decline occurs."

For years, researchers have considered education level as a predictor of cognitive reserve, the ability to preserve higher levels of functioning despite brain injury that occurs over the course of life.

This led Springer and her colleagues to hypothesize that highly educated people would have slower cognitive decline after a stroke.

The results, published in JAMA Network Open, reflect the opposite.

"Dementia is a greater threat after a first stroke than having another stroke," said senior author Deborah A. Levine, M.D., M.P.H., professor of internal medicine and neurology at U-M Medical School.

"We lack treatments that prevent or slow cognitive decline and dementia after stroke. This study increases our understanding and generates potential hypotheses about the causes of post-stroke cognitive decline and which patients face higher risks of it."

Having a higher number of the ApoE4 allele, a genetic risk factor for Alzheimer's disease, did not affect the association between education level and cognitive decline after stroke. The number of strokes a person suffered also did not affect the relationship.

This means, notes Springer, that the critical point of brain injury at which cognitive compensation fails in the highly educated does not depend on underlying genetic risk and can be reached after a single stroke.

"Identifying which stroke patients are at the highest risk for cognitive decline will help target future interventions to slow cognitive decline," Springer said.

Additional authors: Rachel T Whitney, Ph.D., Wen Ye, Ph.D., Emily M. Briceño, Ph.D., Rebecca A. Ferber, Bruno Giordani, Ph.D., Rodney A. Hayward, M.D., Adam S. Kollipara, M.P.H., and Jeremy B. Sussman, M.D., M.S., all of University of Michigan, see remaining authors online.

Funding/disclosures: This research was supported by National Institute on Aging (RF1AG068410) and the National Institute of Neurological Disorders and Stroke (K01NS11755), of the National Institutes of Health.

The National Institute on Aging was not involved in the design and conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. A representative of the National Institute of Neurological Disorders and Stroke is a co-author on the manuscript and reviewed the manuscript for intellectual content but was not directly involved in the design and conduct of the study; collection, management, analysis, or interpretation of the data; preparation or approval of the manuscript; or the decision to submit the manuscript for publication.