What is Vascular Dementia?
Vascular dementia (VaD) is the second most common form of dementia after Alzheimer's disease (AD). It's caused by damage to brain tissue, which occurs because of decreased blood flow. Blood flow to brain tissue may be completely blocked by a clot in a blood vessel, or blood flow may be decreased but not completely blocked by a partial blockage in blood vessels in the brain.
VaD may develop gradually, or it may become apparent after a stroke or after undergoing major surgery, such as heart bypass surgery or abdominal surgery.
Facts about VaD
Dementia and other related diseases and conditions are difficult to distinguish because they share similar signs and symptoms. Although VaD is caused by problems with blood flow to the brain, this blood flow problem can happen in different ways. So, different types of VaD are based on how each type occurs:
- Mixed dementia. In some cases, symptoms of both VaD and AD exist. When mixed dementia occurs, however, it is generally considered to be a form of dementia with some characteristics of AD, rather than a case of AD with characteristics of VaD.
- Multi-infarct dementia. This occurs after several small, often "silent," blockages repeatedly affect blood flow to a certain area of the brain. The changes that occur after each blockage may not be apparent, but over time, the combined effect begins to cause symptoms of impairment. Multi-infarct dementia is also called vascular cognitive impairment.
- VaD is generally caused by conditions that occur most often in older people, such as atherosclerosis (hardening of the arteries), heart disease, and stroke.
- The number of people older than 65 years is increasing.
- People are living longer with chronic diseases, such as heart disease and diabetes.
- Blood clots
- Bleeding because of a ruptured blood vessel
- Damage to a blood vessel from atherosclerosis, infection, or other causes, such as an autoimmune disorder
Men, especially those younger than 75, are affected by VaD more often than women.
Researchers think that VaD will become more common in the next few decades because:
Causes of VaD
VaD is caused by a lack of blood flow to the brain. Blood flow to a certain part of the brain may be decreased or interrupted by:
The effect of decreased or no blood flow depends on the size and location of the area affected. If a very small area in a part of the brain that controls memory is affected, for example, you may experience "forgetfulness" that doesn't necessarily change your ability to carry on normal activities. If a larger area is affected, you may have difficulty thinking clearly or solving problems, or greater memory problems that do change your ability to function normally.
CADASIL (cerebral autosomal dominant arteriopathy with sub-cortical infarcts and leukoencephalopathy) is a genetic disorder that generally leads to dementia of the vascular type. One parent with the gene for CADASIL passes it on to a child, which makes it an autosomal-dominant inheritance disorder. It affects the blood vessels in the white matter of the brain. Symptoms, such as migraine headaches, seizures, and severe depression, generally begin when a person is in his or her mid-30s; however, symptoms may not appear until later in life.