OTHER TYPES OF DEMENTIA
Alzheimer’s is by no means the only form of dementia. Dementia refers to a whole category of conditions in which the brain is affected to such an extreme that the person loses basic cognitive skills such as thinking, remembering, and reasoning, and can no longer perform daily activities.
Some forms of dementia are temporary and treatable, but others, like Alzheimer’s, are irreversible. In irreversible forms of dementia, the focus is on slowing the progression of the disease and treating the symptoms. Among the untreatable forms of dementia are:
Vascular Dementia
Vascular, or multi-infarct, dementia is the second most common kind of dementia and makes up 20 percent of all cases by itself. Another 15 to 20 percent occurs in combination with Alzheimer’s. It typically affects people between 60 and 75 years of age, and is slightly more common in men than women.
The condition results from a series of small strokes or changes in the arteries that supply blood to the brain. These strokes and arterial changes then cause clots in the small blood vessels, which lead to problems in blood flow to the brain, a condition called cerebrovascular disease.
The symptoms of the disease are similar to those in Alzheimer’s: loss of intellectual abilities, difficulties with language, confusion, problems with recent memory, wandering, incontinence, and problems following direction. The person may also demonstrate inappropriate emotional behaviors, slurred speech, and difficulties performing daily activities.
The risk for multi-infarct dementia increases with a history of stroke, with each stroke causing a progressive worsening of the symptoms. People who have high blood pressure and high cholesterol are also at greater risk for vascular dementia.
Over time, the condition may improve or stabilize. But it may progressively worsen with each subsequent stroke.
Binswanger’s Disease
Binswanger’s disease is a rare form of dementia that is sometimes called subcortical dementia. The disease, which is a subtype of vascular dementia, is characterized by cerebrovascular lesions in the deep white-matter of the brain. The condition typically begins in people over the age of 60.
People who develop Binswanger’s disease often have high blood pressure, diseases of the large blood vessels in the neck and heart valves, and abnormalities in the blood. Symptoms of the disease include memory loss, cognition, and mood changes. People who have Binswanger’s may have urinary incontinence, difficulty walking, clumsiness, lack of facial expression, and difficulties with speech. In some cases, the symptoms may appear for a while, and then disappear.
Dementia with Lewy Bodies
When protein deposits called Lewy bodies become widespread in the brain and destroy brain cells, a person is said to have Lewy body dementia. The disease and the characteristic protein deposits were discovered in 1912 by a German doctor named Dr. Friedrich H. Lewy.
No one knows what causes the brain to produce these Lewy bodies, which are small, round inclusions that can be seen only upon autopsy. Lewy bodies are also present in Parkinson’s disease, another degenerative brain disorder that causes stiffness of the limbs, difficulties walking, tremors, and impaired speech. The difference is that in dementia with Lewy bodies, the Lewy bodies occur in both the brainstem and cortical regions of the brain, while in Parkinson’s, they afflict primarily the brain stem.
Although most people still believe vascular dementia is the second-leading kind of dementia after Alzheimer’s, some experts believe that dementia with Lewy bodies holds that dubious distinction. Various autopsy studies suggest that this type of dementia may account for 15 to 25 percent of all cases of dementia. The disease may also occur in people who have Alzheimer’s.
People who have dementia with Lewy bodies experience many of the same symptoms as people who have Alzheimer’s—memory loss, difficulties with language, reasoning, and concentration. However, unlike Alzheimer’s Disease, the progression of the disease is much more rapid, and the patient may experience fluctuations in confusion from one hour to the next. The person may also experience visual hallucinations, which may worsen during times of extreme confusion.
Pick’s Disease
Pick’s disease, also called frontotemporal dementia, is a rare form of dementia that accounts for about five percent of all cases. The disease was named for the Czechoslovakian doctor who first saw the abnormalities in the brain that are associated with the disease, which are called Pick’s bodies. These abnormalities, which are tangles of tau protein, cause neurons to swell and produce the symptoms associated with the disease.
Unlike Alzheimer’s, Pick’s disease affects certain areas of the brain, namely the frontal and temporal lobes, and not the entire brain. The disease usually occurs in people between 40 and 60 years of age, and is slighdy more common in women than men. The onset of the disease is commonly described as slow and insidious, as the tissues in the frontal and temporal lobes gradually shrink.
Symptoms of Pick’s disease include a lack of coordination, the loss of language abilities, the inability to recognize familiar people, places, and objects, and a loss of inhibition. The person may also exhibit mood and personality changes, including greater anxiety, loss of initiative, indecision, and poor judgment. In addition, the person may lose language skills, become socially withdrawn, and suffer a loss of intellectual abilities.
Huntington’s Disease
A person who has Huntington’s disease may also develop dementia as part of the disease’s progression. Huntington’s disease is a degenerative brain disorder that involves the progressive wasting away of neurons in the brain. The condition was first described by an American physician named George Huntington.
Huntington’s disease is considered one of the more common genetic disorders. The children of parents with Huntington’s have a 50 percent chance of developing the condition as well.
The condition begins between die ages of 30 and 45. Symptoms include the progressive loss of mental functions, increasing lack of coordination, personality changes, and abnormal facial and body movements.
Creutzfeldt-Jakob Disease
Until the mad cow disease epidemic in the 1990s, Creutzfeldt-Jakob disease (CJD) was a rare, mostly unheard of degenerative brain disorder. But when mad cow disease swept through the
United Kingdom and struck even young people, scientists discovered that the cause was a variant of CJD, contracted by eating beef that had been tainted with bovine spongiform encephalopathy (BSE), the medical term for mad cow disease. Since then, there have been several other cases in which people contracted CJD and died after eating tainted beef.
Like classic CJD, the variant form brought on by mad cow disease is caused by misshapen brain proteins called prions, which attack healthy brain tissue. After a long incubation period, the person experiences significant and rapid decline in his mental and physical well-being, including profound personality changes, memory loss, impaired thinking, and lack of balance and coordination. Most people die within a year after the symptoms emerge.
In most cases, CJD develops for no apparent reason. But the disease can be transmitted by tainted medical instruments and contact with infected human tissue. In some cases, the disease appears to be inherited.