How does vascular dementia happen?
- A network of blood vessels, called the vascular system, supplies the brain with oxygen. This network allows the brain to function properly.
- If these vessels are blocked, diseased or bleeding, blood is prevented from reaching the brain.
- With no oxygen and nutrients provided by the blood, the affected cells in the brain die, leading to dementia.
This can lead to stroke symptoms that may cause vascular dementia. Stroke symptoms may include paralysis and loss of speech. Read more about stroke below.
Different kinds of conditions affecting the brain’s blood supply can lead to different types of vascular dementia. Two common types are subcortical dementia and cerebral amyloid angiopathy.
Subcortical dementia is caused by small vessel disease, where the small vessels in the brain become stiff and twisted. This results in reduced blood flow to the brain.
Cerebral amyloid angiopathy
Cerebral amyloid angiopathy happens when a protein called amyloid builds up in the brain blood vessels. Amyloid can form plaques, disrupting brain function. This often occurs with Alzheimer’s disease.
The symptoms of vascular dementia are:
- Changes in the ability to make decisions, plan or organize, and
- Difficulties with movement, such as slow gait and poor balance.
Symptoms tend to appear slowly. Specific impairments may occur in steps, where abilities deteriorate, stabilize for a time and then decline again.
There is no one specific test that can diagnose vascular dementia. If vascular dementia is suspected, your doctor will likely perform a number of physical and cognitive tests.
A combination of the physical and cognitive test results, along with a detailed medical history, will provide your doctor with the evidence she or he needs to make a diagnosis.
For more details about how dementia diagnosis processes often work, visit our webpage about what to expect while getting your diagnosis.
Note: Some content in this section has been adapted with permission from the Heart and Stroke Foundation’s 2016 Stroke month report Mind the Connection.
Stroke is a common cause of vascular dementia.
How does stroke occur?
A stroke occurs when blood flow in an artery stops, either because the artery is blocked (an ischemic stroke) or bursts (a hemorrhagic stroke).
This blockage or damage means brain cells aren’t receiving oxygen and nutrients, leading to brain cell death. This may lead to vascular dementia.
Having a stroke more than doubles the risk of developing dementia
Strokes can be large or small, and can have a cumulative effect (each stroke adding further to the problem).
Can you recognize the symptoms of a stroke?
Recognizing the signs of stroke and acting quickly can make a difference in recovery and in lowering the risk of dementia. A stroke can:
- Affect your ability to walk,
- Cause weakness in your arms or legs,
- Cause you to slur your speech,
- Cause changes in your behaviour, such as having emotional outbursts and
- Impact your cognitive abilities such as memory and abstract thinking, holding conversation and processing visual information.
There are different types of stroke
Covert strokes occur when a small blood vessel in the brain becomes permanently blocked.
While overt strokes have recognizable symptoms such as weakness and speech difficulties, covert strokes are subtler and can occur silently without any visible symptoms.
Since covert strokes don’t cause immediate physical changes that are obvious, most people who have had this type of stroke don’t know it.
Transient ischemic attack
Transient ischemic attacks, sometimes called “warning strokes,” are caused by a small clot that briefly blocks an artery.
Transient ischemic attacks and strokes have similar symptoms, but transient ischemic attacks only last a few minutes or hours and cause no lasting damage.
Transient ischemic attacks are an important warning that a more serious stroke may occur. Anyone who experiences a transient ischemic attack should seek medical help immediately.
Other risk factors
Other than stroke, risk factors for vascular dementia include:
- Atrial fibrillation (Afib)
- Heavy alcohol intake
- Heavy drug abuse
- High blood pressure
- High cholesterol
- Physical inactivity
- Sleep apnea
- Unhealthy diet
- Unhealthy weight
For more information about risk factors for dementia, visit our risk factors webpage.
There are currently no medications that can reverse brain damage brought on by vascular dementia.
However, treating the risk factors for stroke significantly reduces the risk of vascular dementia:
- High blood pressure (or hypertension) is the single most important risk factor for stroke and vascular dementia that can be controlled.
- High blood pressure can be managed through physical activity, eating well and by taking the right medication. Talk to your doctor about the appropriate medication to treat high blood pressure.
- Medications may also help control other risk factors for vascular dementia, like diabetes, cholesterol and heart disease.
In general, living a brain-healthy lifestyle will reduce the risk of vascular dementia, delay its onset or slow its progression.
More links, downloads and resources
Vascular dementia. Alzheimer Society of Canada, last updated March 2018. Our information on vascular dementia is also available in a downloadable, print-friendly PDF.
Risk factors. Alzheimer Society of Canada, last updated March 2021. Read about risk factors for dementia in our downloadable, print-friendly PDF infosheet. This sheet also contains strategies and lifestyle changes that can help you reduce your risk of developing dementia.
Stroke risk and prevention. Heart and Stroke Foundation of Canada. On this page, learn more about health conditions that can contribute to stroke as well as the risk factors for stroke that you can and cannot change.
Understanding the Vascular Contributions to Dementia. brainXchange in partnership with the Alzheimer Society of Canada and the Canadian Consortium of Neurodegeneration in Aging (CCNA). This webinar discusses the vascular system in the brain and presents new research findings that maintaining good cardiovascular health may be an important strategy to delay the onset of dementia or slow its progression. Presented by Dr. Cheryl Wellington, Professor in the Department of Pathology and Laboratory Medicine at the University of British Columbia.
Rare Dementia Support Canada. Provides a free specialist Information and support service for people living with, or affected by, a diagnosis of rare or young onset dementia.
This webpage was last updated on June 9, 2023. If you have comments, concerns or questions about this webpage, please email [email protected].