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What is dementia?
Introduction
(Van den Berg 1995)
The term ādementiaā comes from the Latin and literally means āmind goneā: the first syllable ādeā meaning āgoneā, and āmensā being the Latin word for āmindā. The person concerned goes into a steady decline, and the progress of the disease is so destructive that in the last phase the patient bears hardly any resemblance to the person he or she was at the outset. During the (long) first phase, the dementia, as such, is scarcely apparent; the eyes are bright and open, the mind is clear and the patient walks and moves around as he has always done. In the final phase of the disorder, however, he becomes dependent on others for all his needs, and he has forgotten everything he has ever learned. A person with severe dementia comes to the end of his life just as he entered it ā a helpless baby. At that stage, he is only receptive to the atmosphere around him, and to the satisfaction of his most primary human needs.
It was thought for a long time that people with dementia were āmadā and suffering from some kind of mental illness. It has become apparent only fairly recently, however, that this is a misconception, and that dementia is caused by brain dysfunction. The nerve cells in the brain are diseased. In the case of Alzheimerās disease, the nerve cells shrink or wither away ā in a kind of āautumn of the mindā. The brainās control room is not able to function as it should. In the early phase of the disease, sufferers are able to behave fairly normally, because most of the nerve cells are still in good working order. The brain also has amazing reserves at its disposal: when nerve cells fail, others take over their tasks, either partly or in whole, and can continue to do so for a very long time...at least until a critical point has been reached, and there are no more āreserve players waiting on the benchā. The more it affects more parts of the brain, the more striking the changes in the patientās behaviour.
Strictly speaking, a full diagnosis is only possible once a post-mortem examination has been carried out. So long as the patient is still alive, there is no reliable method of determining the nature and degree of the brain tissue damage. Dementia, therefore, is always a āprobableā diagnosis. And sometimes, even the most experienced pathologists are puzzled by the fact that some people who have apparently functioned quite normally for their entire lives are found, during autopsy, to have the same brain abnormality as that found in people with dementia. This means that, even after death, it is not possible in all cases to diagnose Alzheimerās disease with 100 per cent certainty.
The disease begins gradually: silent, like an animal stalking its night-time prey, it takes hold of its victim, and worsens with time.
Dementia in many forms
There are many types of dementia, and dementia ā like cancer, rheumatism and respiratory disorders ā is a collective term. The most common form of the illness is Alzheimerās disease, which is named after the German neurologist Alois Alzheimer, who first described it in 1906.
The first conversation Alois Alzheimer had with Auguste D., the āfirstā Alzheimer patient, began as follows:
Of all people suffering from dementia, roughly 55 per cent have Alzheimerās in its purest form. After Alzheimerās, vascular dementia is the most common and is responsible for 15 per cent of all dementia cases. There are other forms of vascular dementia, the most well-known being the so-called multi- infarct dementia (MID). As the name suggests, this dementia arises from the many (in Latin: multi) small brain infarcts that cause oxygen loss in various parts of the brain which, in its turn, results in brain tissue erosion.
In roughly 15 per cent of cases, we see a combination of two or more disorders which lead ultimately to dementia. The combination of Alzheimerās and vascular dementia occurs most frequently. If we add āpure Alzheimer dementiaā to the 15 per cent mentioned above, it means that roughly 70 per cent of all dementia patients suffer from Alzheimerās disease.
A long line of relatively rare disorders is responsible for the remaining 15 per cent. These diseases, including Parkinsonās disease Pickās disease, Binswanger disease, Lewy Body disease and Huntingtonās disease, occur ā relatively speaking ā more often in younger patients. The same is true of Aids which, in its last phase, can also cause dementia.
Dementia is a syndrome; that is, a group of symptoms or features which appear in combination. Memory loss is always the essence of the illness, and it means in practice that the patientās life pattern undergoes considerable change. As we have said already, there are many types of dementia. Each syndrome has its own cause, or causes, and each has its own process. We will limit ourselves in this chapter to a description of the two most common forms of dementia: Alzheimerās disease and MID.
Both diseases share many similarities, in terms of their symptoms and consequences. There are, however, several important differences. Whilst Alzheimer develops very slowly, MID often begins suddenly with a period of confusion, which is probably the consequence of a mild stroke. This is followed by a period of reasonable recovery, the patientās condition remaining fairly stable until the onset of the next āconfusionā period. Whilst Alzheimer progresses in a way which can be compared to walking down a slight slope, MID is more reminiscent of small steps on a descending track ā two steps down, and one upward step back, and so on.
Because MID is caused by the erosion of many small brain particles, whereby the surrounding area is still able to function reasonably well, these patients are often far longer aware of their own deterioration than Alzheimer patients. When someone with Alzheimerās disease makes a mistake of some kind, and this is pointed out to him, his response is often one of genuine surprise. The recent past is a black hole for him, whilst a similar incident might ring a few more bells for an MID patient, who realizes quite quickly, or remembers vaguely, what he should have known. MID patients are likely to be more conscious of the effects of their illness for a longer period of time.
A male MID patient describes his experiences in these terms:
(Quoted in Van Delft 1993)
The fact that people with dementia are spectators of their own decline over a longer period of time often results in their developing depression.
Whenever the term ādementiaā is used, it usually refers not so much to MID but to Alzheimerās disease. Unless otherwise stated, therefore, the same will be true of the rest of this book.
Prevalence
Dementia is often referred to as the ādisease of old ageā, although the disorder is occasionally known to occur in people under the age of 65 years. Between the ages of 45 and 54, however, only 0.025 per cent of the population suffers from dementia. The incidence figure is st...
