A stroke is a sudden occurrence that happens in an instant. Many of the people who survive strokes report declines in brain functioning post stroke and new research now shows that these problems with memory and thinking ability continue to decline for years afterward at a faster rate than expected of normal brain aging.
“After a stroke, memory and thinking ability continue to decline – faster than for non-stroke survivors. Stroke survivors also had a faster rate of developing cognitive impairment over the years after stroke compared to their pre-stroke rate. The study results are published in the Journal of the American Medical Association this week.”
Lead author Deborah A. Levine and her colleagues from the University of Michigan Medical School used data gathered from 23,572 Americans aged 45 years or older in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study to show how stroke is associated with accelerated and persistent declines in thinking ability over the long term experiment.
“We found that stroke is associated with cognitive decline over the long-term,” says Levine. “That is, survivors had accelerated and persistent declines in memory and thinking ability during the years after stroke — even after accounting for their cognitive changes before and early after the event.”
The participants that took part had no history of cognitive impairment when they entered the large population-based study. Their memory and thinking ability were assessed at the start of the study and at regular intervals during follow-up. They were monitored twice yearly for acute stroke events and suspected strokes were confirmed by physicians using medical records. Over the next six to 10 years, 515 of the participants had a stroke and test results were compared with results of the 23,057 participants who remained stroke-free.
“Because they had information on how stroke survivors’ memory and thinking ability changed over time before the stroke, Levine and her colleagues could separate the declines in brain function associated with aging from declines in brain function associated with stroke.”
The study found stroke to be associated with declines in global cognition, new learning, and verbal memory soon after the event of a stroke as well as accelerated and persistent declines in global cognition and thinking ability post stoke of for number of years.
“Stroke is common, costly, and disabling, and cognitive decline is a major cause of disability in stroke survivors,” says Levine, who holds faculty appointments in internal medicine and neurology at U-M. “Yet cognitive decline after stroke has not received enough attention. We hope these findings will shine a spotlight on stroke survivors’ long-term cognitive needs” said Deborah Levine”
These findings suggest a need for better long-term follow-up care for stroke survivors, including therapy to improve and help retain cognitive ability. Levine and her colleagues also suggested that the study’s results mean long-term cognitive ability could be a new marker for measuring the effects of therapies to treat the initial effects of stroke.
“Our results suggest that stroke survivors warrant monitoring for mounting cognitive impairment over the years after the event,” says Levine. “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 growing and vulnerable stroke survivor population.”
Levine and her colleagues stated that research is needed to determine whether the acute and accelerated long-term cognitive decline post stroke are as a result of incomplete rehabilitation from the initial stroke, subsequent brain injury due to uncontrolled risk factors, behavioural changes, or other underlying mechanisms.