Stroke And Dementia: Understanding The Post-Stroke Cognitive Risk

Dementia is a condition that affects the brain and can impact memory, thinking, communication, mood, and behaviour. It is often progressive and tends to worsen over time. Strokes occur when the blood supply to the brain is interrupted, leading to cell damage or death. This damage can, in turn, cause vascular dementia, which is characterised by problems with reasoning, planning, judgment, memory, and other cognitive functions. The risk of developing dementia after a stroke is significant, with research indicating that about a quarter of people who have experienced a stroke will go on to develop dementia. The onset and severity of vascular dementia depend on the location and extent of the brain damage caused by the stroke. While there is currently no cure for vascular dementia, understanding the link between stroke and dementia can help inform preventative measures and strategies to reduce their impact.

Vascular dementia

The symptoms of vascular dementia vary depending on the area of the brain affected. Common symptoms include problems with planning and organizing, slowed speed of thought, problems with concentration, and memory issues. These symptoms can develop quickly or gradually and tend to be more prominent than memory loss, which is more commonly associated with Alzheimer's disease.

While there is no cure for vascular dementia, treating the underlying vascular disease early on may help prevent it. Maintaining a healthy lifestyle, such as keeping blood pressure and diabetes under control, quitting smoking, and exercising regularly, can also help reduce the risk of developing vascular dementia.

Risk factors

Vascular dementia is a general term for cognitive decline caused by impaired blood flow to the brain. It is often associated with a stroke, which is a disease of the blood vessels in and around the brain. A stroke occurs when the blood supply to an area of the brain is interrupted or cut off, resulting in brain cell damage or death due to a lack of oxygen and nutrients. This damage can lead to vascular dementia.

Age

The risk of vascular dementia increases with age. While it is rare before the age of 65, the risk rises substantially by the 90s. Older people are more likely to have vascular diseases, which can increase the risk of both stroke and dementia.

History of Stroke or Mini-strokes

A history of stroke, mini-strokes, or transient ischemic attacks (TIAs) is a significant risk factor for developing vascular dementia. About 1 in 4 people who have had a stroke will go on to develop signs of dementia within three to six months. The risk of dementia after a stroke is higher than average, and having multiple strokes further increases this risk.

Vascular Conditions

Conditions that damage blood vessels and reduce circulation, such as high blood pressure, abnormal aging of blood vessels (atherosclerosis), and diabetes, can increase the risk of vascular dementia. These conditions can narrow or damage blood vessels, reducing blood flow to the brain and increasing the likelihood of stroke and subsequent dementia.

High Cholesterol

Elevated levels of low-density lipoprotein (LDL), or "bad" cholesterol, are associated with an increased risk of vascular dementia. High cholesterol can contribute to atherosclerosis, which narrows blood vessels and reduces blood flow to the brain.

Smoking

Smoking directly damages blood vessels and increases the risk of atherosclerosis and other circulatory diseases, including vascular dementia.

Obesity

While not directly mentioned in the context of post-stroke dementia, obesity is a well-known risk factor for vascular diseases and is likely also a risk factor for vascular dementia.

Atrial Fibrillation

Atrial fibrillation is an irregular heart rhythm where the upper chambers of the heart beat rapidly and out of sync with the lower chambers. This condition increases the risk of stroke and subsequent dementia as it causes blood clots to form in the heart that can travel to the brain and block blood vessels.

It is important to note that the presence of these risk factors does not guarantee the development of dementia after a stroke, and more research is being conducted to understand the link between stroke and dementia better.

Symptoms

Vascular dementia is a general term for a set of symptoms that affect reasoning, planning, judgment, memory, and other thought processes. It is caused by brain damage from impaired blood flow to the brain. The onset and severity of vascular dementia depend on the location and size of the damaged brain area.

Vascular dementia can occur after a stroke when the blood supply to the brain is interrupted, and brain cells are damaged or die as a result. This can lead to a decline in cognitive functions, including memory, speech, language, thinking, organization, reasoning, and judgment. Changes in behavior and personality may also occur.

The symptoms of vascular dementia vary depending on the individual and the areas of the brain that have been damaged. Some common symptoms include:

• Not being able to understand or respond quickly
• Memory problems
• Difficulty concentrating
• Trouble finding the right words when speaking
• Difficulty planning everyday tasks
• Problems learning new tasks
• Depression or mood changes
• Aggressive or inappropriate behavior
• Loss of bladder control
• Balance issues
• Impaired motor skills

Vascular dementia can develop suddenly after a single stroke or gradually over time, especially after multiple small strokes or "silent" strokes. These silent strokes are so small that the person may not even be aware they are happening, but they can still cause damage and increase the risk of dementia.

In addition to the cognitive and behavioral symptoms, physical symptoms such as paralysis, loss of sensation, or vision problems may also be present after a stroke.

Diagnosis

If you are concerned about vascular dementia, it is important to seek medical advice as soon as possible. The first step is usually to consult your general practitioner (GP), who will discuss your symptoms and conduct initial tests to determine the underlying cause. Here is what you can expect during the diagnosis process:

Initial Consultation with a GP:

• Symptom Discussion: Your GP will talk to you about the symptoms you are experiencing and their severity. They may ask you to describe any changes in your memory, thinking abilities, communication, mood, and behaviour.
• Medical History Review: Your doctor will go through your medical history to identify any pre-existing conditions or risk factors associated with vascular dementia, such as heart problems, high blood pressure, or diabetes.
• Memory and Cognitive Tests: They may perform brief tests to assess your memory, attention, and cognitive functions. These tests help evaluate your ability to organise thoughts, analyse situations, and communicate effectively.
• Mood Assessment: Your GP may ask you questions about your mood to screen for depression or apathy, which are common symptoms of vascular dementia.
• Involving Family or Friends: It is recommended to bring a friend or family member to the appointment. They can provide valuable insights into your symptoms, including any changes they have noticed and the duration of these symptoms.
• Physical Examination: Your GP may request blood tests or urine samples to rule out other potential causes of your symptoms, such as infections, thyroid problems, or hormonal imbalances.
• Medication Review: They will also review your current medications to ensure they are not causing any adverse side effects or interactions that could contribute to your symptoms.

Referral to a Dementia Specialist:

If your GP suspects vascular dementia, they may refer you to a dementia specialist for further evaluation. These specialists include old-age psychiatrists, geriatricians, neurologists, psychologists, or specialist dementia nurses. The assessment may take place at a memory clinic or a hospital outpatient department.

Specialist Evaluation:

• Detailed Cognitive Testing: The specialist will conduct comprehensive tests to assess your memory and thinking abilities. These tests may include pencil-and-paper exercises designed to challenge your cognitive functions.
• Brain Imaging: They may arrange for you to undergo a brain scan, such as an MRI or CT scan, to visualise the extent of damage to your brain and identify areas affected by the stroke(s).
• Neuropsychological Evaluation: This involves a detailed assessment of your cognitive functions, behaviour, and emotional state. The specialist will ask you questions and may use standardised tests to evaluate your condition.

Final Diagnosis:

Based on the results of these evaluations, the specialist will make a diagnosis. It is important to remember that there is no single test for vascular dementia, and the diagnosis is often based on a combination of factors, including your symptoms, medical history, cognitive test results, and brain imaging findings.

Next Steps:

Once vascular dementia is diagnosed, the focus shifts to managing the condition and providing support. While there is currently no cure for vascular dementia, treatments are available to help manage symptoms and slow down the progression of the disease. This may include medications to control blood pressure, reduce cholesterol, prevent blood clots, and manage diabetes or Alzheimer's disease. Additionally, various therapies, such as speech therapy and physical or occupational therapy, can help improve cognitive functions and maintain independence.

Treatment

While there is no cure for vascular dementia, there are treatments that can help slow down the progression of the disease and improve the patient's quality of life. Here are some recommended treatments for managing vascular dementia:

Preventing Additional Strokes

Preventing future strokes is crucial for slowing down or stopping the progression of vascular dementia. This can be achieved by managing existing conditions such as high blood pressure, high cholesterol, heart disease, and infections. Maintaining a healthy lifestyle through a balanced diet, regular exercise, and quitting smoking can also help reduce the risk of future strokes.

Medications

Although there are no medications specifically designed for vascular dementia, doctors may prescribe drugs used to treat other types of dementia, such as Alzheimer's disease. Cholinesterase inhibitors and memantine (Namenda) are commonly recommended as they can help boost the levels of chemical messengers in the brain involved with memory, judgment, and information processing.

Lifestyle Changes

Making lifestyle changes can be an important part of the treatment plan for vascular dementia. This may include increasing cognitive stimulation through brain exercises, breaking down routines into smaller, more manageable steps, and adhering to rehabilitation guidelines. Psychotherapy can also be beneficial for managing symptoms of depression or anxiety, which are commonly associated with vascular dementia.

Specialist Referrals

In some cases, patients may be referred to specialists such as old-age psychiatrists, geriatricians, neurologists, psychologists, or specialist dementia nurses. These specialists can provide further assessments, brain scans, and additional support to help manage the condition effectively.

Early Intervention

Prompt intervention after a stroke is crucial for reducing the risk of long-term complications, including dementia. If a person experiences stroke symptoms, it is important to seek emergency medical care to prevent damage and potentially prevent the development of vascular dementia.

Frequently asked questions