As described earlier, dementia involves a progressive decline of intellectual ability. A declining memory alone is inadequate evidence upon which to make the diagnosis. In addition to the difficulty with remembering things there is usually a progressive loss of the ability to think and to reason that can also affect other areas of mental functioning, for example emotion and behaviour. Most people, even the very old, do not become demented.
The simplest of the medical definitions of dementia is ‘a global loss of intellectual function that is usually progressive and in the majority but not all cases untreatable’. The most important word in this definition is the term ‘global’, as this reinforces the fact that memory loss alone is not the same as dementia, and that there have to be other aspects of abnormal mental functioning.
It has already been mentioned that hardening of the arteries by itself does not cause dementia, but there are also other misconceptions that need to be corrected. It is not caused by under-use or over-use of the brain, and it affects people in all walks of life. With the exception of one or two very rare conditions it is not infectious — one person cannot transmit it to another. It is also not an inevitable consequence of ageing. Although it may sometimes appear to be precipitated by a stressful event, the most common example of this being the family who attribute the onset of dementia in one ageing parent to the strain of the bereavement and grief caused by the death of the other, this is not so. In these circumstances, careful inquiry will usually reveal that the intellectual changes had probably been present for some time before the bereavement occurred, but that the person who died was assisting the sufferer so that waning mental abilities were less noticeable. When the spouse dies, the surviving partner is suddenly left exposed to the world at large, and his or her failings become more obvious.
There are so many different underlying conditions that can cause dementia that it is difficult to provide an overall picture of the way in which dementia affects personality and behaviour. For the two most common causes of dementia, Alzheimer’s disease and multiple infarct dementia, the details are described in the appropriate chapters, but they will be seen to be very similar to the account which follows, representing a rather general picture of the features that are most frequently found in people suffering from a dementing illness. It is very unlikely that any one person with dementia will show all the changes in behaviour described.
In the early stages, often the first thing that is noticed is that the normal degree of forgetfulness that some older people experience becomes much worse, perhaps sufficient to interfere with their day to day life. They may also have difficulty in understanding new information, which may have to be repeated to them several times. In many cases, a person who has been house-proud is not so careful as he or she once was, and one can notice a deterioration in the cleanliness of the home, and sometimes of clothes.
Meanwhile the forgetfulness may continue to get worse but it becomes more apparent that the major difficulty is with recent or short-term memories whereas those dating back many years, even to childhood, are preserved, sometimes in amazing detail. People with dementia may therefore forget what they had for lunch, or even that they had lunch only an hour or two ago, but recall with some precision the contents of a meal eaten on a special occasion such as a birthday sixty or more years ago. At a practical level this memory loss can be quite a problem, as it may result in kettles and saucepans being put on the cooker and allowed to boil dry, a gas stove or fire being turned on but not lit, and so on. Times become muddled and it is easy for a person with dementia to become lost in familiar places, for example when out shopping. Sometimes, thoughtful relatives provide an electric cooker to replace one that runs on gas, or an electric fire to replace a gas fire in the hope of reducing the risk of fire or explosion. Unfortunately, this doesn’t always help, as the person for whom it is intended may be unable to master the techniques involved in working the new apparatus, simple though they may appear to be.
Disorientation in time may lead to the person with dementia getting up in the middle of the night to go off to work to a job retired from twenty years earlier, and to which he or she would normally have set off at, say, 8.30 in the morning. On one occasion, the retired owner of a factory in his late seventies insisted on returning to his previous office at 3 a.m. each night, seven days a week. Rather than upset him, his family went along with his wishes until he insisted that other members of the staff were also there at that time. Eventually they sought medical advice and he was treated for his abnormal behaviour, so that he was once again able to sleep through the night.
These changes in behaviour may also affect the personality of sufferers and it is this that is often so hurtful and upsetting to those closest to them. Repetitive questioning, either as an expression of the need for reassurance or because the previous answer has been forgotten, constant wandering, aggression, noisiness, and emotional instability take their toll, especially of those that love them.
At a variable point in the progress of the dementia, usually in the early or middle stages, language becomes affected. To begin with it may be forgetfulness of the correct word and this can often be circumvented, e.g. by asking if someone will pass the ‘thing that you write with’, rather than using the term ‘pencil’. Sadly, however, even this ability declines. Some people with dementia become unable to understand the meanings of some words, even if they are in common everyday use, such as knife, fork, or cup. If this happens early in the course of the disease it often results in frustration and irritability.
Most of us from time to time forget someone’s name. Nevertheless when we meet them, we know exactly who they are and can place them in the appropriate context – we remember perfectly well where we last saw them, what their job is, where they live, and so on. Often their name comes back to us out of the blue some time afterwards. This can also happen to people with dementia, to a greater extent than in the rest of us. More serious, however, is an apparently similar situation in which they forget who somebody is, not just what their name is. It can be extremely hurtful to a wife to be mistaken for her husband’s former secretary and treated as such, or for a daughter to be mistaken for the sufferer’s mother.
As the disease progresses, general abilities required for normal, everyday life deteriorate progressively. With many of the dementing illnesses it almost appears a matter of ‘last in first out’; the more complex activities one learns in childhood are lost in the reverse order to that in which they were learned. Eventually sufferers may appear to lose all concern for social convention, relieving themselves in public, undressing at inappropriate times and in inappropriate places, stealing, and engaging in other embarrassing forms of behaviour. Physical dependence becomes in the end considerable and even walking becomes difficult or impossible. Some but by no means all people with dementia become bedridden.
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