Dementia is a disorder of the brain in which there is a progressive loss of memory and other intellectual functions so that the mind gradually ceases to function normally and the affected person slowly becomes increasingly confused, incapable of sensible conversation, unaware of his or her surroundings, and generally incapacitated.

Dementia may occur at any age. It is often called "presenile" when it occurs before age 65 and "senile" in those over 65. But the vast majority of people over 80 retain normal brain function.

What Are The Causes?

Dementia may result from any of several underlying causes. In some cases, it is from brain damage caused by narrowing and blockage of the arteries that supply blood to the brain [multi-infarct dementia, more commonly known as hardening of the arteries]. Deprived of an adequate blood supply, the cells in many small regions of the brain degenerate and die. At one time, this degeneration of the arteries and the natural consequences of aging were thought to be caused mainly by Alzheimer's disease. However, research has now shown that Alzheimer's disease is responsible for nearly 80 percent of dementia cases at all ages.

The underlying cause of Alzheimer's disease is not known, but in families in which several individuals have developed the disease before the age of 65, there is a genetic factor,. Wide publicity has been given to research reports suggesting a link between Alzheimer's disease and water supplies that contain high levels of aluminum, but most physicians remain unconvinced that any form of toxicity from metals in relevant. Current studies have established the precise physical effects of the disease on brain tissue. The brain becomes shrunken from the loss of nerve cells, and the nerve tracts become distorted as the protein called amyloid is deposited in the person's brain.

Dementia also sometimes occurs---usually in young or middle-aged people---as a result of rare neurological disorders such as Creutzfeld-Jakob disease [which is caused by a virus], a brain tumor, or infection associated with acquired immune deficiency syndrome [AIDS].

Dementia is by definition progressive and incapacitating, but when it begins in the presenile years, the mental deterioration tends to advance more rapidly and to be more widespread and severe than when the onset occurs later in life.

In people over the age of 65, the early symptoms of senile dementia may resemble the forgetfulness typical of aging, and many older people may worry that they are becoming demented. However, do not assume the signs of confusion or impaired intellectual capacity in someone over 65 are always from senile dementia. There may be an underlying, and treatable cause. It has been estimated that 10 to 20 percent of people over 65 who have an intellectual impairment have reversible conditions. Important causes of confusion in older individuals are side-effects from medications and another illness, which may place added stress on the brain's already depleted reserves. For example, depression, chest infections, or urinary tract infections, stroke, heart attack and hypothermia can result in mental confusion, and so can a low blood sugar level. Symptoms that resemble senile dementia are sometimes caused by long-term abuse of alcohol or other drugs or by vitamin deficiency, syphilis, or brain disorders such as tumors or subdural hemorrhage and hematomas. Very often many of these symptoms will decrease in intensity when the condition is properly treated.

What are the symptoms?

The earliest signs of dementia may be so subtle that even the most perceptive physician fails to notice them. Most often it is an observant relative, friend, or employer who first becomes aware of a certain lack of initiative, forgetfulness, and irritability on the part of the affected person. Most characteristic of dementia at the onset is the gradual loss of memory, especially for recent events. You may notice that the person cannot remember what has happened a few hours [or even moments] earlier, although he or she can recall what happened many years ago. As weeks and months pass the person's powers of reasoning and understanding dwindle, and he or she may lose interest in all familiar pursuits, even in such simple activites as watching television or seeking news of relatives and friends. Eventually this disorder may cause a complete disintegration of the personality.

Dementia often leads to emotional and physical instability. Many people swing between apathy and aggression, and tears and laughter, at the slightest provocation [or even no predictable provocation]. Odd, unpredictable behavior may appear, along with uninhibited and antisocial actions. A person's table manners may deteriorate, personal cleanliness is sometimes neglected, and usual politeness abandoned. Some people may even become violent if their impulsive behavior is frustrated.

A few affected individuals lose their sexual inhibitions, as well, which can lead to their making inappropriate, embarrassing physical advances to people of either sex.

More unusual disturbances of thought and intellect, including apraxic disorders [in which there is an inability to coordinate muscles and movements], and problems with space perception may also occur in the later stages of Alzheimer's disease.

In advanced stages of Alzheimer's, there is generalized stiffness of the muscles, with slowness and awkwardness in all movements. Eventually the person may lose all ability to perceive, think, eat, control bladder or bowels, or move. This gradual collapse of the individual's intellectual and physical capabilities may progress slowly, lingering over 10 years or more.

What are the risks? The older a person is, the greater is his or her likelihood of having symptoms of dementia. About 10 percent of people over the age of 65 have some intellectual impairment, and it is estimated that there are about 4 million people in the US who have senile dementia. In the general population, about one family in every 10 includes at least one older member who has this condition.

There are risks whenever mentally impaired people live alone, especially after they have progressed beyond an early stage of dementia. Because of forgetfulness and a decreased ability to concentrate, there is danger of fires, falls, and other accidents. Combined with possible physical disabilities such as impaired hearing or vision, mental confusion makes it difficult for some older people to take medications as prescribed, to cross streets safely, or even to use the bathroom. Without some supervision a person with dementia may eat poorly and neglect personal hygiene. It also can be distressing if, as often happens, the person becomes incontinent.

If a relative of yours is in the early stages of senile dementia and insists on traveling alone, even locally, you can help minimize the danger involved. Be sure that he or she always carries some form of identification such as a bracelet inscribed with his or her name and address as well as your phone number. At the very least, give your relative a piece of paper or card with your address and telephone number on it, and make sure that he or she always carries it.

What should be done?

If you suspect that a relative or close friend is showing signs of dementia, gently persuade [or take] him or her to see a physician. After taking a personal history, making a physical examination, and testing memory and reasoning power, the physician will probably look for symptoms of an underlying disease, such as vitamin B12 deficiency, that might be causing the mental deterioration. Further series of laboratory tests and a CT scan or MRI test may be done to look for the unmistakable signs of brain shrinkage associated with Alzheimer's disease. In addition, the physician may check for the presence of looped or tangled fibers that are also characteristic of Alzheimer's disease, and to exclude other causes of dementia.

All cases of dementia should be investigated thoroughly, since some can be cured and others helped to a certain extent. Drug treatments for Alzheimer's disease are currently being evaluated in the US and in Europe, but despite some optimistic reports published in newspapers, none has been shown to have any substantial effect on the course of the disease.

Whatever the age of the individual with dementia, a consistent approach to treatment is necessary. Even in the earliest stages of the condition, when many people affected by dementia are still able to live alone, some form of daily attendance is important to guard against potential disasters, such as turning on the kitchen stove and wandering away. Friends and relatives can help by organizing memory aids, lists, and routines, and by making sure that the person has adequate food and warmth. It is essential to maintain a regular mealtime schedule because dementia patients often forget to eat. They eat so little that they become undernourished [even to the point where they develop a deficiency disease] and emaciated.

If you assume responsibility for the care of a relative suffering from dementia, do not hesitate to seek assistance from community services. Your physician may also be able to arrange for your relative to be admitted in to a nursing facility for brief periods so that you can have occasional relief from your responsibilities. Your physician can also give you advice on how to cope with such specific problems as incontinence.

Eventually, however, your relative may require the skilled and constant care that is available only in high-quality nursing facilities. If your physician strongly recommends this form of care, you may be doing the person the best possible service by following your physicians recommendations.