More than half of all stroke survivors may develop cognitive impairment within a year after their stroke, and one in three are at risk for developing dementia within five years. That is according to a new American Heart Association (AHA) scientific statement published today in the journal Stroke, which advises post-stroke screenings and comprehensive interdisciplinary care to support stroke survivors with cognitive impairment.
“Cognitive impairment is an often underreported and underdiagnosed yet very common condition that stroke survivors frequently deal with,” said Nada El Husseini (Duke University Medical Center, Durham, USA), chair of the scientific statement writing committee. “Stroke survivors should be systematically evaluated for cognitive impairment so that treatment may begin as soon as possible after signs appear.”
An AHA scientific statement is an expert analysis of current research and may inform future guidelines. According to the recent statement, entitled “Cognitive Impairment After Ischemic and Hemorrhagic Stroke”:
- Cognitive impairment after stroke is common in the first year after a stroke, occurring in up to 60% of stroke survivors. It is most common within the first two weeks after a stroke.
- About 40% of people who survive a stroke have cognitive impairment during the first year after the stroke that does not meet diagnostic criteria for dementia, yet it still impacts their quality of life.
- Up to 20% of stroke survivors who experience mild cognitive impairment fully recover cognitive function, and cognitive recovery is most likely within the first six months after a stroke.
- Post-stroke cognitive impairment is often associated with other conditions, including physical disability, sleep disorders, behavioural and personality changes, depression and other neuropsychological changes—each of which may contribute to lower quality of life.
“Cognitive impairment after stroke ranges from mild impairment to dementia and may affect many aspects of life, such as remembering, thinking, planning, language and attention, as well as a person’s ability to work, drive or live independently,” El Husseini said.
There is no gold standard for cognitive screening after a stroke, according to the scientific statement. However, some brief screening tests (30 minutes or less) are widely used to identify cognitive impairment after a stroke: the Mini-Mental State Examination and the Montreal Cognitive Assessment.
While early detection during the initial hospitalisation for stroke is important for immediate care planning, it is also important to assess cognitive changes over time, the statement continues. Stroke survivors who experience unexplained difficulties with cognitive-related activities of daily living, following care instructions or providing a reliable health history may be candidates for additional cognitive screening.
When cognitive impairment is detected, healthcare professionals are encouraged to assess an individual’s daily functioning with neuropsychological screenings, which evaluate areas of brain function that affect behaviour, and may provide a more thorough picture of the individual’s cognitive strengths and weaknesses. Healthcare professionals are also encouraged to offer guidance to patients and their caregivers regarding home safety, returning to work and driving after a stroke, and connect caregivers and stroke survivors to community resources for social support.
Interdisciplinary collaboration among healthcare professionals, such as physicians, speech language therapists, occupational therapists, neuropsychologists and nurses, is often needed for optimal monitoring and care for people with cognitive impairment after a stroke. The AHA statement further suggests behavioural cognitive rehabilitation and physical activity may help improve cognition after a stroke.
Preventing another stroke is a key consideration to prevent the worsening of cognitive impairment after a stroke. This includes treatments for stroke risk factors, such as high blood pressure, high cholesterol, Type 2 diabetes and atrial fibrillation. Blood pressure control is associated with reduced risk for recurrent stroke and for mild cognitive impairment too.
There are unanswered questions regarding how cognitive impairment develops after stroke, and the impact of non-brain factors—including infection, frailty and social factors. Further research is needed to determine best practices for cognitive screening after a stroke, including the development and use of screening instruments that consider demographic, cultural and linguistic factors in determining “normal” function, the statement details.
“Perhaps the most pressing need, however, is the development of effective and culturally relevant treatments for post-stroke cognitive impairment,” El Husseini concluded. “We hope to see big enough clinical trials that assess various techniques, medications and lifestyle changes in diverse groups of patients that may help improve cognitive function.”