AN INTRODUCTION TO DEMENTIA

The term "dementia" refers to a range of symptoms commonly found in people with brain diseases which result in the damage and loss of brain cells. Losing brain cells is a natural process, but with illnesses leading to dementia this occurs at a much faster rate and results in the person's brain not functioning in a normal manner.

The symptoms of dementia normally involve a gradual and slow deterioration of the person's ability to function, which never improves. The brain damage affects the person's mental functioning (memory, attention, concentration, language, thinking, etc.) and this in turn has repercussions on behaviour. But dementia is not just limited to the degenerative types of dementia. It refers to a syndrome which does not always follow the same course of development. In some cases the person's condition may improve or remain stable for some time.

A small percentage of cases of dementia are treatable or potentially reversible, but in the vast majority of cases dementia leads to death. Most people die of "complications" such as pneumonia rather than of dementia itself. However, if it begins very late in life, the effects tend to be less severe. Although Alzheimer's disease is the most common form of dementia, there are a number of different kinds of dementia.

Different kinds of dementia

Aids

It has now been established that HIV has a direct effect on the brain. About 8-16% of AIDS victims develop a slow and progressive form of dementia.. When dementia does occur, it is usually in the later stages of the disease, although there may be some symptoms earlier on. Symptoms include confusion, difficulty concentrating, apathy, blunted emotions and withdrawal or loss of inhibitions. Patients, nevertheless, tend to maintain many aspects of their original personality until the end.

Alcohol related dementia

Prolonged, heavy drinking of alcohol can lead to a form of dementia. However, stopping drinking altogether and eating a balanced diet can bring about improvements. Excessive drinking can also cause Korsakoff's syndrome which leads to significant memory loss, although it must be noted that strictly speaking, Korsakoff's syndrome is not a form of dementia.

Binswanger's Disease

Binswanger's disease is a slowly evolving type of dementia, which occurs as a result of disease in the smaller blood vessels. Symptoms tend to include slowness, lethargy, difficulties walking, paralysis of the limbs and emotional instability.

Creutzfeldt-Jakob Disease (CJD)

Creutzfeldt-Jakob disease is usually transmitted accidentally through surgical processes, although in rare cases it can be hereditary. There is currently much controversy as to whether beef infected with bovine spongiform encephalopathy (BSE) is responsible for cases of CJD in humans. Recent studies have revealed a number of younger people (average age of 26) presenting the symptoms of CJD and researchers believe that a new strain of CJD has been identified. The symptoms of CJD are quite similar to those of Alzheimer's disease, particularly in the early stages. Patients suffer from the odd lapse of memory and mood swings and may be inclined to withdraw from social activities. This is followed by more significant memory problems, difficulties with conversation and a loss of stability. As the disease progresses, they develop jerky, uncontrollable movements, stiffness of the limbs and become incontinent. CJD generally progresses rapidly in that most patients die within about six months, although with some people (about 10%), the disease can last from 2 to 5 years.

Diffuse lewy body disease

This form of dementia seems to be linked to Parkinson's disease, but also affects about a fifth to a quarter of people diagnosed as having Alzheimer's disease. The disease is characterised by the presence of Lewy bodies (tiny spherical structures containing proteins) which can be found in the nerve cells of the brain at post-mortem. This kind of dementia tends to be fairly mild. Patients suffer from movement disorders, tremors, depression, delusions and confusion, although their condition can fluctuate considerably, even within the same day. It has also been found that people with diffuse Lewy body disease are more sensitive to certain medication used to treat behaviour problems.

Down's Syndrome

Down's syndrome is a learning disability which is caused by a chromosomal disorder. People with Down's syndrome (DS) have an extra copy of chromosome 21 inside each cell in the body. In the past (e.g. in the 1950s) people with DS rarely lived beyond the age of 15. However, since then there have been significant improvements in antibiotics and heart surgery and this has meant that people with DS now live well into their fifties and sixties. Unfortunately, a large percentage of people with DS who live over 40, develop Alzheimer's disease (some 30 to 40 years earlier than most of the general population who eventually develop this disease).

Gerstmann-Straussler-Scheinker Syndrome

This disease is usually inherited. Symptoms include a loss of balance and poor muscle co-ordination with dementia occurring in the later stages.

Huntington's Disease (chorea)

This progressive and fatal neurological disorder, which was first described in 1872 by George Hungtington, causes mental and physical deterioration. It usually starts between the ages of 30 and 50 and tends to last from 10 to 25 years. In is an inherited disease which is transmitted by a single dominant gene. This means that 50% of children having a parent with Huntington's disease will develop it if they live long enough. A test exists to determine whether an adult has the inherited gene. Most people with Hungtington's disease develop dementia. Symptoms frequently include forgetfulness, slight involuntary movements, clumsiness, irrational behaviour and depression. In addition to this, patients tend to become moody, irritable, quarrelsome, very sensitive and may develop delusions of persecution. Physical symptoms include a characteristic jerking and abrupt movements which usually start in the hands, face and shoulders.

Multi-Infarct Dementia (MID)

This form of dementia is caused by a series of small strokes which cut off the blood supply to certain areas of the brain causing brain cells to die. The areas of the brain mainly affected are those which control memory, speech, language and learning. Although symptoms vary considerably from person to person and over time, speech problems, mood swings, epileptic fits and partial or total paralysis of a limb are fairly common. The symptoms also vary over time in that after the initial deterioration due to the stroke, the patient's condition may seem to stabilise. However, unfortunately these small improvements do not last long.

Parkinson's Disease

This is a progressive neurological disorder. People with Parkinson's disease tend to have difficulty walking, writing and dressing etc. because they lose a high percentage of the neurotransmitter dopamine, which helps to control movement. Between twenty to thirty percent of sufferers develop dementia in the late stages of the disease. Those who do not, nevertheless, have difficulty concentrating or think more slowly.

Pick's Disease / Frontal lobe dementia / Fronto-temporal degeneration

Frontal lobe dementia is the term used to describe a number of forms of dementia which involve damage to the brain cells mainly in the frontal lobe of the brain. Pick's disease is one such form. As damage occurs in the part of the brain which controls behaviour, this form of dementia is often marked by noticeable changes in the personality of the person affected. The person may be rude, arrogant, act inappropriately and basically fail to respect social conventions. The early stage tends to be marked by a lack of initiative and failing memory for recent events. Spatial disorientation also occurs quite early on. In the later stages, patients are bed-ridden. Pick's Disease has an average age of onset between 52 and 57 years and an average duration of 6 to 7 years.