The Connection Between Stroke and Dementia

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Research has shown that strokes and dementia might be connected. However, it's important to know that there are some key similarities, and differences, between the two.

This article will go how strokes and dementia are related. You will learn about the ways that these conditions are similar as well as how they can affect one another.

Medical professional bending down talking to older woman in a wheelchair
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What Is Dementia?

Dementia is a group of conditions that affect brain functions, including memory, language, and personality. These changes take place over time and can make it harder for a person to go about their daily life.

There are different kinds of dementia. While they share some features, they do not all have the same causes.

A few examples of types of dementia include:

  • Alzheimer's disease (AD) is the most well-known dementia. It usually begins between the ages of 65 and 85. The symptoms include memory loss, anxiety, sleep problems, delusions, and depression. Although rare, hallucinations may also occur. Alzheimer's usually progresses slowly.
  • Frontotemporal dementia is a group of disorders that affect the frontal and temporal lobes of the brain. These dementias usually start between the ages of 50 and 60 and progress slowly but are generally faster-moving than other dementias (like Alzheimer's).
  • Lewy body dementia is a brain disease that happens when proteins (Lewy bodies) build up in the brain. The cause of the condition is unknown. The symptoms include changing levels of consciousness, visual hallucinations, movement problems, and rapid eye movement (REM) sleep behavior disorder.
  • Parkinson's dementia is a group of disorders that can develop in people with Parkinson's disease. This type of dementia is always preceded by the progressive movement symptoms of Parkinson's.
  • Vascular dementia is a type of dementia that is caused by strokes, silent strokes, and other forms of cerebrovascular disease. A person may have symptoms without even realizing they had a stroke. The symptoms can range from mild to severe.

What Is a Stroke?

A stroke happens when the blood supply to the brain is interrupted. This usually happens for one of two reasons:

When the brain isn't getting enough blood, it causes a range of signs and symptoms depending on which part of the brain is affected.

FAST

Knowing the acronym FAST can help you spot a stroke and help someone get medical care right away:

  • Facial drooping
  • Arm weakness
  • Speech difficulties
  • Time to call emergency services

Here are some of the most common signs and symptoms of a stroke:

  • Facial drooping that is usually on one side (e.g., may only affect one eye)
  • Weakness in a limb (e.g., arm or leg on one side of the body)
  • Trouble talking (e.g., slurred speech, trouble coming up with the word they want to say, mixing up words)
  • Vision loss
  • Severe headache
  • Confusion
  • Dizziness

Can Strokes Cause Dementia?

Research has found connections between strokes and dementia, but not all of them have a cause-and-effect relationship. The exception is vascular dementia, which is caused by a stroke.

Vascular dementia is also called stroke-related dementia.

Having a stroke changes a person's brain. They may not think or behave how they did before. If these changes get worse with time, it can be a sign of vascular dementia.

People with vascular dementia after a stroke may show signs of forgetfulness, inappropriate behavior, personality changes, emotional instability, or even lose their sense of humor.

These symptoms can start suddenly or happen gradually and get worse as time goes on.

When someone has vascular dementia, they might not be able to take care of themselves. This can put them at risk for falls, injuries, and even another stroke.

Can Vascular Dementia Be Prevented?

Because vascular dementia is caused by reduced blood flow to the brain, understanding your stroke risk factors can be an important preventative step.

You can talk to your provider about your stroke risk at a routine medical check-up. They can help you find ways to lower your risk.

Prevention is also important if you already have dementia because having a stroke can make the symptoms worse.

Is Dementia Always Related to Strokes?

People with other types of dementia may also have a stroke—especially if they have other stroke risk factors. However, just because they have dementia does not mean they'll have a stroke.

On the other hand, having a stroke might make a person more likely to develop dementia, but researchers are still trying to understand the link.

Here's what research has shown about strokes and other types of dementia:

  • Alzheimer's disease: Having a stroke might increase the risk of Alzheimer's. People with Alzheimer's who have had strokes often have more severe symptoms than people with the condition who have not had strokes.
  • Frontotemporal dementias: This group of dementias, which includes Pick’s disease, primary progressive aphasia, motor neuron disease, and frontotemporal degeneration, are related to genetics. They are not believed to be related to stroke.
  • Lewy body dementia: Some research has shown that Lewy body dementia might be linked to an increased risk of stroke. However, other studies have shown that people with the condition are less, not more, likely to have strokes.
  • Parkinson's disease: Studies have found that people with Parkinson's might be at higher risk of having a stroke. Having a stroke can also make Parkinson's symptoms worse.
  • There is also a condition called vascular Parkinsonism which is caused by a stroke. It is not the same as Parkinson's disease, but it has similar symptoms. This condition happens when small strokes affect the areas of the brain that control movement.

More research is needed to understand how strokes and dementia are connected. It's important to know that not everyone who has a stroke will develop dementia. Likewise, people with dementia can have strokes that are not related to their condition.

Summary

Strokes and dementia are both conditions that affect the brain. While they have some similarities, they are also different. Researchers are still learning about how the conditions are related and might influence each other.

Vascular dementia is caused by a stroke. In turn, having another stroke can make the symptoms of the condition worse. That's why prevention is important.

People with other forms of dementia, like Alzheimer's, can also have strokes. Many risk factors for dementia are also risk factors for a stroke.

However, more research is needed to determine whether other forms of dementia cause strokes, or whether strokes can cause other forms of dementia.

A Word From Verywell

If you've had a stroke, you might worry that you will now be more likely to get dementia. On the other hand, if you're living with dementia, you might worry that you're at a higher risk of having a stroke.

There's still a lot that we don't know about strokes and dementia are related. Based on what we do know, prevention is key.

Finding out your risk factors for dementia and strokes is a step that you can take right now to help support your brain health.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institutes of Health. National Institute on Aging. What is dementia? Symptoms, types and diagnosis. Reviewed December 31, 2017.

  2. MedlinePlus. Alzheimer's disease.

  3. National Institutes of Health. National Institute on Aging. Alzheimer's and hallucinations, delusions, and paranoia.

  4. Centers for Disease Control and Prevention. Stroke signs and symptoms.

  5. NHS. Vascular dementia.

  6. National Institutes of Health. National Institute on Aging. What is Alzheimer's disease? Reviewed May 16, 2017.

  7. National Institutes of Health. National Institute on Aging. Vascular contributions to cognitive impairment and dementia. Reviewed December 31, 2017.

Additional Reading

jose vega, md, phd

By Jose Vega MD, PhD
Jose Vega MD, PhD, is a board-certified neurologist and published researcher specializing in stroke.