In a study of nearly 24,000 participants, those who experienced a stroke had an acute decline in cognitive function and also accelerated and persistent cognitive decline for six years.
Each year, approximately 795,000 U.S. residents experience a stroke, according to a 2015 report from the American Heart Association. In 2010, almost 7 million adults were stroke survivors, according to the report. Cognitive decline is a major cause of disability in stroke survivors, past research has shown. The magnitude of survivors’ cognitive changes after stroke has been uncertain, according to background information in the article.
In the study, Deborah A. Levine, MD, MPH, of the University of Michigan Medical School and Ann Arbor VA Health System, and colleagues examined the changes in cognitive function among survivors of incident stroke, controlling for their prestroke cognitive trajectories. Findings were published in the July 7 issue of JAMA.
The study included 23,572 U.S. participants age 45 years and older without cognitive impairment at study entry (2003-07), and followed up through March 2013. During a median follow-up of 6.1 years, 515 participants (306 white, 209 black) survived incident stroke and 23,057 remained stroke free. Participants are in the Reasons for Geographic and Racial Differences in Stroke, or the REGARDS, study.
The primary outcome measured was change in global cognition, and secondary outcomes were changes in verbal memory, cognitive impairment, new learning and executive function, which regulates a person’s ability to organize thoughts and activities, prioritize tasks, manage time and make decisions.
The researchers found stroke survivors had a significantly faster rate of incident cognitive impairment after stroke compared with the prestroke rate, controlling for the odds of developing cognitive impairment before or acutely after the event. Findings showed incident stroke was associated with accelerated and persistent declines in global cognition and executive function, after accounting for individuals’ cognitive changes before and acutely after the event. Researchers also found significant, acute declines in new learning and verbal memory after stroke but no acceleration of prestroke rates of change in these functions.
“Our study has potential implications for clinical practice, research, and healthcare policy,” the authors wrote. “Although clinical practice guidelines and quality improvement programs recommend cognitive assessments be performed for patients with stroke before hospital discharge and also in the postacute settings, our results suggest that stroke survivors also warrant monitoring for mounting cognitive impairment over the years after the event.
“Moreover, our results suggest that long-term cognitive dysfunction is a potential domain for evaluating acute stroke therapies,” they wrote. “As adults increasingly survive stroke, cases of poststroke cognitive impairment will multiply. Given that poststroke cognitive impairment increases mortality, morbidity, and healthcare costs, health systems and payers will need to develop cost-effective systems of care that will best manage the long-term needs and cognitive problems of this increasing and vulnerable stroke survivor population.”
This work was supported by a cooperative agreement from the National Institute of Neurological Disorders and Stroke, National Institutes of Health and the Department of Health and Human Services. Additional funding was provided by a grant from the National Institute on Aging.
Showing change before, after stroke
In an accompanying editorial, Philip B. Gorelick, MD, MPH, and David Nyenhuis, PhD, of the Michigan State University College of Human Medicine, Grand Rapids, wrote the study was unique because it allowed for prestroke cognition to be tracked and provided rates of cognitive change before incident stroke.
They added the visuals included in the article illustrate the findings and show what might happen to a person’s cognition before and after stroke. According to Gorelick and Nyenhuis, the figures might be a helpful educational tool for non-healthcare workers and patients.
“Clinicians should remain alert for the presence of clinically manifest stroke or silent stroke identified incidentally on neuroimaging study, because these findings may be harbingers of future major complications such as recurrent stroke, cognitive impairment and disability,” Gorelick and Nyenhuis wrote in the editorial.
“Information gained from cognitive screening can be used to plan for daily management of patient care based on cognitive performance and need for possible formal neuropsychological testing,” they wrote. “In addition, intensification of vascular risk management may be indicated for patients at risk of cognitive impairment in an attempt to prevent subsequent stroke, myocardial infarction, loss of cognitive vitality and overall disability.”