Vascular dementia: A look at dementia caused by strokes

Dementia is a condition that affects memory, thinking, and reasoning, leading to impaired day-to-day function. Vascular dementia (dementia due to strokes), alone or in combination with a degenerative disease such as Alzheimer's, is one of the most common forms of dementia. While vascular dementia can't be cured, certain treatments may help slow its progression.

What is vascular dementia?

The brain needs a constant supply of oxygen-rich blood to function properly. Vascular dementia occurs when blood flow to the brain is reduced or blocked, either suddenly or gradually, resulting in damage to brain cells. This damage can lead to issues with thinking, memory, and other cognitive functions, which are key signs of dementia.

Causes of vascular dementia

The cause of vascular dementia is strokes. Large clotting strokes occur when a blood clot blocks a blood vessel in the brain, cutting off its blood supply. Risk factors for large strokes include heart disease including an irregular heartbeat (atrial fibrillation), and cholesterol plaques in the large arteries of the neck (such as the carotids). These large strokes are typically noticed immediately by the individual or their family.

Strokes can also be caused by the obstruction of tiny blood vessels, and thus are often called small vessel disease. Over time, the small blood vessels in the brain can be damaged by high blood pressure, diabetes, and high cholesterol — the same conditions that can lead to heart disease. When small vessels in the brain are occluded, blood flow to those parts of the brain is cut off.

Strokes can also occur due to a brain bleed or hemorrhage.

Who is at risk for vascular dementia?

Things that increase your risk for stroke also raise the likelihood of developing vascular dementia. Some common risk factors for stroke and vascular dementia are:

• Age: The risk of vascular dementia increases with age, especially after age 65.

• High blood pressure: Long-term high blood pressure can damage blood vessels in the brain, due to the high-pressure pounding of the blood, leading small vessels to become occluded.
• Diabetes: High blood sugar damages blood vessel walls, leading small vessels to become occluded.
• Smoking: Smoking harms blood vessels and can increase your risk of both large and small strokes.
• High cholesterol: High cholesterol levels can cause the buildup of plaque in arteries, leading to an increase in risk of both large and small strokes.
• Heart disease: Conditions that affect the heart and blood vessels, such as coronary artery disease or atrial fibrillation, can increase the risk of large strokes.
• Other lifestyle factors: Heavy alcohol intake, lower physical activity levels, and obesity are also known risk factors for strokes and vascular dementia.

Although your age can't be changed, most other risk factors can be managed or improved.

Symptoms of vascular dementia

Different parts of the brain control different functions, so the symptoms of vascular dementia can vary depending on the part of the brain that is affected. In some cases, symptoms can appear suddenly, such as after a large stroke, while in other cases they may develop more slowly over time due to the accumulation of small strokes.

People who suffer from vascular dementia often struggle with executive functioning, which includes tasks like planning, organizing, and decision-making. These are the processes that help you manage everyday tasks. When executive function is impaired, it becomes harder to think things through, make choices, and remember important details. Othercommon symptoms of vascular dementia, that are also present in other dementias such as Alzheimer's disease, include:

• memory problems such as difficulty remembering recent events or names
• difficulty concentrating
• slowed thinking
• confusion or feeling disoriented, especially in unfamiliar situations
• mood changes such as depression, anxiety, and mood swings.

Early symptoms may be mild in some cases, but often worsen over time. More advanced symptoms of vascular dementia (and other causes of dementias) may include:

• aphasia: difficulty speaking, understanding words, reading, or writing
• apraxia: trouble performing movements or tasks
• difficulty with balance leading to frequent falls
• loss of bladder control.

How do symptoms of Alzheimer's disease differ from vascular dementia?

Vascular dementia and Alzheimer's disease share some similar symptoms, such as memory loss and confusion. However, there are key differences in how these symptoms appear.

Vascular dementia often has a quicker, more noticeable onset, with physical symptoms like coordination and walking difficulties appearing earlier. This is particularly true when the cause of vascular dementia is large strokes. In contrast, Alzheimer's disease usually begins with memory and cognitive issues, with physical symptoms like balance problems emerging in the later stages.

The progression of these conditions also varies. People with vascular dementia due to large strokes tend to have a stepwise progression, with periods of quick declines followed by stability. Alzheimer's disease progresses more gradually and relentlessly, with cognitive impairment worsening slowly over the years, making changes harder to detect from day to day. However, vascular dementia due to small vessel disease can, like Alzheimer's, progress slowly over years.

How is vascular dementia diagnosed?

Diagnosing vascular dementia requires a thorough assessment from a healthcare provider. This often starts with a detailed medical history. Your doctor will ask about any previous strokes or heart-related conditions, as well as symptoms you've noticed. It can be helpful to bring a loved one to the appointment to share their observations. The doctor will also perform a physical examination and evaluate your neurological function.

Other techniques used in diagnosis include:

• Blood tests: These can help identify underlying health conditions, such as diabetes or high cholesterol, that may be contributing to vascular dementia.
• Cognitive tests: These tests evaluate memory, problem-solving skills, and other aspects of thinking.
• Neuropsychological testing: More advanced testing that can assist in distinguishing vascular dementia from Alzheimer's disease and other forms of dementia.
• Brain imaging: Scans, such as an magnetic resonance imaging (MRI) or computed tomography (CT) scan, are essential for making the diagnosis of vascular dementia, as these images can visualize the strokes. MRI scans are more sensitive and are the preferred test. Other imaging tests, such as flurodeoxyglucose (FDG) or amyloid positron emission tomography (PET) scans, can be used to search for other causes of dementia (such as Alzheimer's disease) that may be present with vascular dementia or may be causing the dementia by itself.

Treatments to slow progression of vascular dementia

The FDA has not approved any medications specifically for treating vascular dementia, but the following interventions can help slow its progression, manage symptoms, and improve quality of life.

Managing risk factors that could cause additional strokes is a key treatment approach. Your doctor may prescribe medications to control your blood pressure, cholesterol, and blood sugar, and to prevent blood clots.

If needed, procedures to open the carotid arteries such as endarterectomy, angioplasty, and stenting may be done to improve blood flow to the brain.

Certain medications can improve memory and cognitive function in people with Alzheimer's disease, and these drugs may be prescribed for some people with vascular dementia. They include cholinesterase inhibitors such as donepezil (Aricept), galantamine, and rivastigmine (Exelon), as well as the NMDA-receptor and dopamine agonist memantine (Namenda). Dextromethorphan, by itself or with quinidine (Neudexta), can help with the emotional changes that often accompany vascular dementia.

Cognitive or occupational therapy may be recommended to help manage physical or emotional symptoms and improve daily functioning. And lifestyle changes like regular aerobic exercise, quitting smoking, and eating a heart-healthy Mediterranean menu of whole foods can help improve overall health and protect the brain.

Preventing vascular dementia: Steps you can take to lower your risk

Here are some tangible steps you can take to lower your risk of vascular dementia by protecting healthy blood flow to the brain:

• Manage chronic conditions: Keep your blood pressure, cholesterol, and blood sugar levels in a healthy range through a combination of healthy diet, regular exercise, and medication.
• Stop smoking: Quitting smoking can reduce the risk of blood vessel damage and improve brain and overall health.
• Exercise regularly: Aerobic exercise improves blood flow to the brain and is associated with a lower risk of all causes of dementia. Aim for 150 minutes of moderate-intensity physical activity every week.
• Eat a healthy diet: A whole-food diet rich in fruits, vegetables, and lean proteins can help keep your blood vessels healthy. The DASH (dietary approach to stop hypertension) diet and the Mediterranean diet have both been linked to slowing down memory and thinking problems in older adults.