Cognitive Impairment After Stroke Equivalent to 8 Years of Aging

Ischemic stroke
Ischemic stroke
Stroke impaired cognitive function equally in both blacks and whites.

Having a stroke can produce a drop in brain function equivalent to nearly eight years of aging, according to data published in Stroke.

The study, headed by a team from the University of Michigan, sought to determine causes of racial differences in cognitive decline, but found that both black and white adults were impacted the same after incident stroke.

“As we search for the key drivers of the known disparities in cognitive decline between blacks and whites, we focus here on the role of ‘health shocks’ such as stroke,” said study author and University of Michigan Medical School assistant professor Deborah Levine, MD, MPH. “Although we found that stroke does not explain the difference, these results show the amount of cognitive aging that stroke brings on, and therefore the importance of stroke prevention to reduce the risk of cognitive decline.”

The researchers collected data from 4,908 black and white participants aged ≥65 years that had no prior history of stroke or cognitive impairment but who suffered a stroke within 12 years of their first survey and cognitive test in 1998. Data from a 27-item memory and thinking speed test was analyzed alongside Medicare data for the cohort. Participants’ cognitive test scores were measured from 1998 to 2012.

Although the effect of incident stroke on cognition did not statistically differ between races, black participants did show a greater degree of cognitive decline than whites (adjusted difference in modified version of the Telephone Interview for Cognitive Status score, 1.47 points; 95% confidence interval, 1.21 to 1.73 points). This confirms the differences in cognitive aging seen between black and non-Hispanic whites, but also confirms that stroke does not appear to play a role in these differences.

The authors noted that factors such as how long a person has had vascular risk factors, quality of education, as well as genetic factors may play a role in racial differences in cognitive performance over time.

One thing that is especially clear from the study results is the effects of stroke on brain function. The researchers emphasized the important of stroke prevention methods, including blood pressure and cholesterol control, not smoking, and control of diabetes that need to be put into action in order to help preserve cognitive health. 


  1. Levine DA et al. Stroke. 2015; doi:10.1161/STROKEAHA.114.008156.