What is it?
Vascular dementia is an umbrella term that describes impairments in cognitive function caused by problems in blood vessels that feed the brain.
In some cases, a blood vessel may be completely blocked, causing a stroke. Not all strokes cause vascular dementia. It depends on the severity of the stroke, where the stroke occurred and the portion of the brain that's affected. Vascular dementia also can occur when blood vessels in the brain narrow, reducing the amount of blood flow to those sections of the brain.
The prevalence of vascular dementia ranges from 1 to 4 percent in people over the age of 65. Because few treatments are available for vascular dementia, prevention is crucial.
Vascular dementia symptoms can vary, depending on the portion of the brain that's affected. People with vascular dementia can experience:
- Confusion and agitation
- Problems with memory
- Unsteady gait
- Urinary frequency, urgency or incontinence
- Night wandering
- A decline in the ability to organize thoughts or actions
- Difficulty planning ahead
- Trouble communicating details sequentially
- Memory loss
- Poor attention and concentration
Vascular dementia symptoms often begin suddenly and may worsen in a stepwise fashion, following a series of strokes or ministrokes. But some forms of vascular dementia develop gradually and can easily be confused with Alzheimer's disease.
Adding to the confusion, Alzheimer's disease and vascular dementia often occur together. In fact, some scientists believe that it's more common for these two disorders to occur together than apart.
Vascular dementia is most often caused by either a:
- Complete blockage of blood vessels in the brain. The complete blockage of an artery in the brain usually causes a stroke (infarction), but some blockages don't produce stroke symptoms. These "silent brain infarctions" increase a person's risk of vascular dementia. The risk increases with the number of infarctions experienced over time. One variety of vascular dementia is called multi-infarct dementia. Heart disease and irregular heart rhythms, such as atrial fibrillation, can increase your risk of stroke.
- Narrowing of the blood vessels in the brain. Vascular dementia also can occur without a complete blockage of an artery. Portions of the brain can be starved for oxygen and food by reduced blood flow from arteries narrowed by vascular disease.
Vascular dementia can also be caused by:
- Profoundly low blood pressure
- Brain damage caused by brain hemorrhage
- Blood vessel damage from such disorders as lupus erythematosus or temporal arteritis
Risk factors for vascular dementia include:
- Increasing age. This is one of the biggest risk factors for vascular dementia. The disorder is rare before the age of 65. And people in their 80s and 90s are much more likely to have vascular dementia than people in their 60s and 70s.
- History of stroke. The brain damage that occurs with strokes appears to increase the risk of developing dementia.
- Hardening of the arteries (atherosclerosis). Atherosclerosis occurs when plaque builds up in your arteries and narrows your blood vessels. This can increase your risk of vascular dementia.
- High blood pressure. Hypertension puts extra pressure on blood vessels throughout the body. This increases the risk of vascular problems in the brain.
- Diabetes. High glucose levels damage blood vessels throughout the body, increasing the risk of stroke and other vascular problems in the brain.
- Smoking. Smoking increases the risk of hardening of the arteries and other vascular diseases, including vascular dementia.
- High cholesterol. High levels of bad cholesterol (LDL) are associated with an increased risk of vascular dementia, and possibly with a higher risk of Alzheimer's disease.
If vascular dementia is suspected, your doctor may recommend one or more of the following tests:
- Computerized tomography (CT). A CT scan uses special X-ray equipment to produce a cross-sectional image showing a slice of your body's organs and tissues. A contrast material may be injected to help highlight any abnormalities in your brain's blood vessels.
- Magnetic resonance imaging (MRI). An MRI scan uses radio waves and a strong magnetic field to produce detailed images of internal organs and tissues. In some cases, contrast material may be injected to produce even more detailed pictures. Some people experience a feeling similar to claustrophobia when they're inside an MRI machine. If you think this will be a problem, your doctor can prescribe medication to help you relax.
- Positron emission tomography (PET). During a PET scan, you'll be injected with a low-level radioactive material, which binds to chemicals that travel to the brain. You lie on a table while an overhead scanner tracks the radioactive material. This helps show which parts of your brain aren't functioning properly. The test is painless and can be particularly useful in distinguishing between different types of dementia.
- Doppler ultrasound. Doppler ultrasound uses high-frequency sound waves to measure the direction and speed of blood cells as they travel through blood vessels — such as the carotid arteries, which travel through either side of your neck to connect your heart and brain. A Doppler ultrasound of your carotid arteries can help your doctor determine if there are blockages or narrow places impeding blood flow to your brain.
- Neuropsychological tests. Neuropsychological tests assess orientation, learning, recall, attention, calculation and language. Exam results for people with vascular dementia typically show the same types of cognitive deficits as the exam results of people who have Alzheimer's disease. One major difference, however, is in memory function. Most people with vascular dementia don't experience memory problems until later in the course of the disease unless there is a stroke in the exact area of the brain that controls memory.