New Study Finds Majority of Stroke Survivors Experience This Alarming Symptom
A new scientific statement details the lingering cognitive impacts of stroke.
People who experience stroke have a higher risk of developing cognitive impairment and even dementia.
Doctors say more research is needed to find the proper screening and treatment for these patients.
More than 795,000 people have a stroke in the U.S. each year, and it can cause lingering effects. Stroke is the leading cause of long-term disability and a new scientific statement shows it can have a major impact on cognitive decline.
The statement, which was published in the journal Stroke and written by the American Heart Association (AHA) and American Stroke Association (ASA), involved a review of randomized controlled clinical trials, along with other studies and clinical guidelines. Based on the findings, the researchers discovered that up to 60% of all stroke survivors develop cognitive impairment within a year and a third develop dementia within five years. (Cognitive impairment, in case you aren’t familiar with the term, is difficulty with memory, concentration, and learning new things, per the Centers for Disease Control and Prevention (CDC).)
The researchers also found that, for about 40% of stroke survivors, the cognitive impairment isn’t severe enough that they meet the criteria for dementia—but it still impacts their quality of life. The findings also suggest that up to 20% of stroke survivors who have mild cognitive impairment fully recover within about six months of a stroke.
The statement’s authors said that the findings show that there is a need for more studies on post-stroke cognitive impairment (PSCI) and how it relates to the risk of developing Alzheimer disease and related dementias.
But why does this link exist and what can be done to help people who have had a stroke? Neurologists break it down.
Why might stroke raise the risk of cognitive impairment and dementia?
The statement’s authors are clear that this link is still being explored. Still, they said that the risk of cognitive impairment and dementia is likely due to a series of events in the body that may be related to preexisting changes in the vascular system and brain.
“Cognitive impairment after stroke is common within the first year and not well studied,” says Adi Iyer, M.D., a neurosurgeon and interventional neuroradiology, of Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, Calif.
However, there are some theories on what may be at play. “One of the leading thoughts is that it has to do with this underlying burden of vascular risk factors and disease—things like diabetes and hypertension,” says Andrea L. Schneider, M.D., Ph.D., an assistant professor of neurology at the University of Pennsylvania Perelman School of Medicine. “Both are risk factors for stroke and dementia.”
The stroke itself may also be responsible for cognitive decline, she says. “Many people initially have very significant cognitive dysfunction after having a stroke,” Dr. Schneider says. “Some of it is from the stroke injury itself, whether it’s cutting off a blood vessel or bleeding in the brain. But after the acute injury, people can improve—and some may have lingering deficits.”
Dr. Schneider says this is an “active, ongoing area of research,” with doctors still trying to figure out what can be behind this link and who is the most at risk.
Signs of cognitive impairment
Stroke can leave patients with a range of complications. But stroke patients who experience cognitive impairment may have the following signs, according to the CDC:
Memory loss
Asking the same question or repeating the same story
Not recognizing familiar people and places
Having trouble exercising judgment
Changes in mood or behavior
Vision problems
Trouble planning and carrying out tasks, like following a recipe or keeping track of monthly bills
How stroke survivors are currently screened
The ASA notes that stroke survivors are currently given “brief tests” of 30 minutes or less to screen for cognitive issues after a stroke. But, the organization says, there is no gold standard for this and it’s crucial to screen survivors for cognitive issues when they’re hospitalized after a stroke, along with assessing them for changes in their cognitive skills over time.
Dr. Iyer stresses the importance of monitoring these patients. “Before patients who have suffered from strokes return to work or start driving, for example, it is critical for clinicians to understand their functional limitations,” he says. It’s also important for them to have “more guided cognitive therapy to give patients the best chance of meaningful recovery,” he says.
The ASA also says that stroke risk factors like high blood pressure, high cholesterol, type 2 diabetes, and atrial fibrillation, should be addressed to lower the risk of another stroke and the risk that they could have cognitive impairments that get worse.
“Given its prevalence, cognitive therapy should be a necessary adjunct to physical therapy during recovery,” Dr. Iyer says. “Like physical exercise, mental exercise is essential for patients to make a more complete recovery.”
But Dr. Schneider stresses that there’s still a lot left to be discovered when it comes to the link between stroke, cognitive impairment, and dementia. “The ideal post-stroke cognitive test…we don’t know what that is yet, unfortunately,” she says. “What we do know is that having a multidisciplinary approach to post-stroke care is key.” That involves having care from a neurologist, along with physical rehabilitation, occupational therapy, and speech therapy, she says.
Dr. Schneider says the scientific statement is a “huge contribution to the literature” and “brings to the forefront that it’s not just motor deficits after a stroke that contribute to a disability.”
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