Vascular dementia exists in a large number of forms, some of which have minimal impact on daily life, some of which are devastating. The spectrum of vascular dementia includes:
- Mild vascular cognitive impairment (MVCI),
- Multi-infarct dementia,
- Single-infarct dementia (damage to a single, critical location in the brain),
- Vascular dementia with lacunar lesions deep in the white matter, pons, or basal ganglia,
- Vascular dementia due to hemorrhagic (bleeding) lesions,
- Binswanger disease, and
- Mixed dementias, a combination of Alzheimer's disease and vascular dementia.
Mild vascular cognitive impairment (MVCI)
Mild vascular cognitive impairment — which the DSM-5, the diagnostic guide that American psychiatrists use for defining disease conditions calls, Mild Vascular Neurocognitive Disorder — causes more memory loss than is expected for people who don't have it, but not so much memory loss that it would be considered dementia.
Multi-infarct dementia causes small areas of damage across the neural network of the brain. People who have this form of vascular dementia usually suffer multiple sudden episodes of neurological deterioration. They may suddenly lose function in a leg, or suddenly lose their vision, or suddenly lose their speech. Symptoms may relapse and remit, sometimes better and sometimes worse, but the general trend of the disease is increasing disability. It occurs in steps, rather than gradually. However, many people with this form of dementia retain many of their cognitive abilities to the very end.
Single-infarct dementia is damage to a localized region of the brain, rather than impairment throughout the brain. Typically the onset of symptoms is sudden, but not as progressive as multi-infarct dementia.It is more likely to manifest itself as a single event than as a series of losses of function.
Vascular dementia with lacunar lesions
Lacunar lesions occur in the deeper layers of the brain.Atherosclerosis or a blood clot that forms in the arteries in this part of the brain interrupts the connection between the brain stem and the cerebral cortex. There can be difficulty talking, difficulty walking, clumsiness, loss of sensation in part of the body, or loss of control over a muscle group in the face or limbs. If high blood pressure is not controlled, multiple "mini-strokes" and transient ischemic events can occur. Loss of cognitive function is tied up with the localized loss of sensation and motor function caused by loss of circulation in this part of the brain.
Vascular dementia with hemorrhagic (bleeding) lesions
This form of dementia may start with an "incredible headache". There can be loss of speech or difficulty understanding speech, numbness in an arm or leg, vision changes, seizures, and loss of attention span. The underlying cause of this form of vascular dementia may be arteriovenous malformations, tangled blood vessels that eventually break in the spine or in the brain. Or it can result from a brain aneurysm or be a bad reaction to a blood thinning medication.
Binswanger's disease, also called subcortical leukoencephalopathy, is caused by damage to the white matter. The white matter is nerve fibers. Binswanger's disease slows down the flow of information through these nerve fibers. The results include slow movements, loss of muscle control, changes in gait, and changes in posture that coincide with falls, seizures, and loss of bladder control. People with Binswanger's disease slow down so much that they can't do everyday tasks like cooking and driving.
About 10 percent of elderly people who have vascular dementia of some kind also have Alzheimer's disease. The effect of having both conditions is a combination of slowly progressive and sudden, stepwise declines in function of body and mind.
How do all of these forms of vascular dementia compare with Alzheimer's disease, with which most of us are more familiar?
- People with vascular dementia tend to have better recall and fewer memory problems that people who have Alzheimer's.
- People with vascular dementia tend to be more perserverative, that is, they tend to keep trying to do the same thing, more than people who have Alzheimer's. This gives people with vascular dementia difficulty with abstract thinking and difficulty shifting tasks.
- The physical symptoms of vascular dementia tend to be more localized than those of Alzheimer's. Someone with a vascular dementia may present a pseudobulbar affect disorder, crying or laughing without feeling sad or happy. (Having a pseudobulbar affect disorder does not necessarily mean someone has dementia.) They may have slow movements or hyperactive reflexes. They may suffer hemiparesis, weakness on one side of the body, or ataxia, an inability to coordinate muscle movements.