Vascular dementia

Vascular dementia occurs when blood vessels in the brain, specifically arteries, are damaged. These arteries deliver blood from the heart to the brain. Our blood contains oxygen and nutrients that help the brain cells to work properly. When blood vessels are damaged, this reduces blood flow to the brain cells. This affects how our brain cells work and causes them to become damaged too, which can lead to symptoms of dementia, like memory and thinking problems.

Sometimes this blood vessel and brain cell damage can cause memory and thinking problems that are mild and therefore are not diagnosed as dementia. This is sometimes called vascular mild cognitive impairment.

 

Types of vascular dementia

There are different causes of vascular dementia depending on how the blood vessels have been damaged. Not everyone is told a specific cause for their vascular dementia at the time of diagnosis, and sometimes someone can have more than one cause of vascular dementia.

 

Post-stroke dementia

Post-stroke dementia means the development of dementia after having a stroke. A stroke occurs when blood supply to a part of the brain is suddenly cut off. This usually happens when a large artery within the brain is blocked by a blood clot. Sometimes it can be because an artery bursts and bleeds into the brain. This is called a haemorrhagic (bleeding) stroke and is usually due to a weakness in the artery wall, called an aneurysm.

A stroke can cause problems with movement, sensation coordination, speech or sight depending on the part of the brain affected.

If someone has problems with memory and thinking after a stroke which do not improve over time, they may be diagnosed with post-stroke vascular dementia. Roughly one in three people who have a stroke go on to develop dementia.

Unfortunately, people who have a stroke are more likely to have more strokes, and so have a higher risk of developing dementia in the future. Post-stroke dementia can also be caused by multiple smaller strokes which cause progressive damage to the brain. Some of these smaller strokes are called ‘mini-strokes’ or ‘transient ischaemic attacks’. Sometimes these strokes can be so small, that someone may not experience any symptoms or know that they are having one. However, over time, the damage to the brain leads to dementia.

 

Small vessel disease (SVD) of the brain

Vascular dementia can also be caused by damage to small arteries that supply blood to the brain. This is called small vessel disease (SVD). Because these small arteries only supply a very tiny area of the brain, when the damage occurs it is not noticeable to the person.

However, over time the damage can spread and lead to dementia. Every part of the brain contains these small arteries, so the area of the brain affected by SVD can vary from person to person. However, common symptoms for people with SVD include problems with concentration and thinking, changes in personality or mood, loss of memory, difficulty walking or problems with balance.

The damage to blood vessels and brain cells caused by small vessel disease happens over many years. Someone with SVD may not notice these changes until it starts to affect their memory and thinking, which will get worse over time.

The main cause of small vessel disease is high blood pressure (also known as hypertension). SVD can also be caused by the build of the protein amyloid in arteries in the brain. This is the same protein involved in the development of Alzheimer’s disease, and so someone can have both conditions at the same time. This is often called mixed dementia.

 

You can find more information about the causes of vascular dementia in our blog here.