Increased risk of stroke in people with cognitive impairment

People with cognitive impairment are significantly more likely to have a stroke, with a 39% increased risk, than people with normal cognitive function, according to a new study published in CMAJ (Canadian Medical Association Journal).

"Given the projected substantial rise in the number of older people around the world, prevalence rates of cognitive impairment and stroke are expected to soar over the next several decades, especially in high-income countries," writes Dr. Bruce Ovbiagele, Chair of the Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, with coauthors.

Cognitive impairment and stroke are major contributors to disability, and stroke is the second leading cause of death world-wide. Although stroke is linked to the development and worsening of cognitive impairment, it is not known whether the reverse is true. Previous studies that have looked at the link between cognitive impairment and subsequent stroke have been inconsistent in their findings.

The study in CMAJ, by researchers in the United States, Taiwan and South Korea, analyzed data from 18 studies of 121 879 people with cognitive impairment, of whom 7799 later had strokes. Most of the included studies were conducted in North America or Europe.

The researchers observed a significantly higher rate of stroke in people with cognitive impairment than in people with normal cognitive function.

"We found that the risk of future stroke was 39% higher among patients with cognitive impairment at baseline than among those with normal cognitive function at baseline," write the authors. "This risk increased to 64% when a broadly adopted definition of cognitive impairment was used."

Stroke symptoms often include cognitive impairment. Cognitive deficits may manifest in different ways including confusion, memory problems, decreased mental ability, impulsiveness, distractibility, impaired judgement, executive dysfunction, and agnosognosia (patient's inability to recognize his/her impairment).

Confusion - The stroke victim may appear disoriented, have short term memory loss, or demonstrate bizarre or unusual behavior. Confused patients will have problems sustaining a meaningful conversation. Sometimes a patient may appear confused but actually have aphasia which is a speech disorder where the patient can have difficulty producing or comprehending speech. See the aphasia page for more information.

Memory Problems - Memory loss after a stroke is not uncommon. It can present as an inability to learn and recall new information or remember and retrieve long term memory. Sometimes the loss is subtle, and a caregiver may not notice memory problems until the patient attempts more complicated activities of daily living. Ideas to help the stroke patient with memory deficits, include establishing a standard daily routine, keeping frequently used items in a designated place, and making a memory notebook for important information.