What is dementia?
Dementia is a term used by doctors to describe a progressive deterioration in mental powers accompanied by changes in behaviour and personality.
The story we told about Ralph in the last chapter illustrates some of the changes that are most frequently seen in someone who is suffering from the early stages of dementia. Individuals, of course, differ in the way that they respond to a disease. Depending on their age, the sort of person they are and their physical health, the symptoms may vary a little between one person and another.
WHAT ARE THE SYMPTOMS OF DEMENTIA?
The symptoms of dementia include memory loss, personality changes, disorientation, inability to perform daily routine activities and difficulty in communication.
The most common problems of dementia
• Deterioration of memory
• Disorientation
• Changes in personality and behaviour
• Loss of practical everyday skills
• Difficulty in communicating
Memory loss
This is a common feature of dementia, and the memory for recent events is affected first. The capacity to remember further back in time usually remains unaffected until the disease is at a more advanced stage. The ability to store recent information deteriorates because of the changes in the brain that occur in diseases such as Alzheimer’s. In the early stages, this problem with short-term memory may not create too many difficulties; after all, many people find that their memories are less good as they get older. But, as the disease progresses, memory loss will become more severe. Sufferers may set out on an errand, for example, and then forget where they were going, or they may have a meal and later forget that they have eaten. In the later stages, they may even forget the names of people close to them.
Disorientation
Closely connected to the failure of memory is the loss of the ability to orientate oneself in direction or time. Many sufferers from dementia show signs of being disorientated, not knowing where they are or the correct year, month or day of the week. Sometimes they may get day and night muddled up, wanting to go out in the middle of the night or sleep during the day. You will remember from the last chapter how Ralph appeared bewildered when he was any distance from home. This deterioration in the ability to find one’s way around becomes more marked as the disease advances. Sufferers may become more likely to wander away from home and get lost, which can pose a particular problem for those caring for them. In the later stages of the illness, they may have problems finding their way around their own home.
Personality and behaviour
Some sufferers’ personalities seem to remain much as they were before the onset of the disease, but others may show quite striking changes. Social withdrawal and a loss of interest in usual activities are common. People with dementia may experience uncharacteristic mood swings, or some underlying part of their personality may become much more pronounced. They may develop a tendency to spitefulness or anxiety, for example. Some people seem to undergo drastic alterations in personality, changing perhaps from being gentle and placid most of the time into a person prone to outbursts of temper and aggression.
As the disease progresses, many sufferers start to behave in ways that are socially unacceptable, and may do or say things that would once have seemed quite inappropriate for them.
Loss of practical skills
In the last chapter we saw how Ralph lost the ability to accomplish everyday tasks and how he found it hard to concentrate on anything for any length of time. This is one of the features of dementia. Sufferers have difficulty in performing actions that they used to manage easily, such as driving a car, cooking and, as the disease gets worse, even dressing or washing themselves.
Difficulty in communication
In the early stages of dementia people may have difficulty in finding the correct word to use when they are speaking. This makes it harder for them to engage in complicated conversations, and taking down messages over the telephone can be a particular problem.
Later, they may be unable to finish sentences, wandering off on to another subject, or they may repeat words over and over again. The ability to read and write may also be affected.
It becomes more difficult to find the right word when speaking as the disease progresses and, as powers of comprehension also decline, conversation becomes increasingly harder.
Non-verbal forms of communication, such as touch and expression, become very important for those caring for people in the later stages of dementia.
The medical label of dementia doesn’t amount to a complete diagnosis. A number of separate diseases can produce the symptoms of dementia and it is important to find out which of these is the cause.
Some can be treated successfully although, unfortunately, there are others about which little can be done at the moment.
Possible causes of dementia
♦ Alzheimer’s disease
♦ Stroke or vascular dementia
♦ Dementia with Lewy bodies
♦ Frontotemporal dementia
♦ Vitamin B12 deficiency
♦ Underactive thyroid
♦ Drug interactions
♦ Hereditary diseases of the nervous system
♦ Delayed effects of repeated head injury
WHAT CAUSES DEMENTIA?
Alzheimer’s disease
Alzheimer’s disease is the most common cause of dementia in elderly people living in the UK. In a very few cases the disease occurs because of a defective gene. The gene is inherited, so several members of the same family may be affected. We must emphasise, however, that this is an unusual reason for developing Alzheimer’s disease, and most cases are not caused by this genetic abnormality. Scientists have not yet discovered the cause for the much more common form of this condition, which does not run in families. An enormous amount of research is being devoted to Alzheimer’s disease at the moment, and some of the recent advances and current theories are described on pages 52–3.
Scientists have also been studying what happens to the nerve cells in the brains of sufferers. When a powerful microscope is used to look at a thin slice of brain from a patient with Alzheimer’s disease at high magnification, two unusual features, not present in the brains of normal people, can be seen. These features are called senile plaques and neurofibrillary tangles. The plaque is an accumulation of an abnormal protein called amyloid. One theory of Alzheimer’s disease suggests that this plaque forms because the processes that normally operate to clear away this protein have become defective. Neurofibrillary tangles are skeins of another abnormal protein but, unlike the senile plaque, the tangle is found inside the nerve cells. The reason why these tangles develop is not properly understood, but once again it seems that the normal processing of protein by the cell is disrupted in some way. These tangles choke up the nerve cells and prevent them from working properly.
Vascular dementia
Almost every part of the body needs to be supplied with blood – it carries oxygen and nutrients to the tissues and takes away carbon dioxide and other waste products of metabolism – and the brain is no exception. It is a very active organ and is richly supplied with blood through a dense network of many millions of tiny blood vessels.
If some of these tiny blood vessels become blocked, they can no longer carry out their function of delivering blood. This is what happens when someone has a mild stroke. The areas of the brain that they previously supplied become short of oxygen, and some of the nerve cells die. An area of tissue that has died because of lack of oxygen is called an infarct.
Widespread disease of the small blood vessels can lead to the appearance of many tiny infarcts throughout the substance of the brain. It is not too hard to understand that, although each individual infarct is very small, the cumulative effect of many infarcts will disrupt normal brain function. Sometimes this form of dementia is called multi-infarct dementia.
Our blood vessels tend to get narrower as we get older. The process is a little like the furring up of pipes and kettles that occurs in hard water areas of the country. However, disease of small blood vessels is particularly common in people who have had high blood pressure for a long period of time, and it may be made worse by smoking cigarettes.
Mixed dementia
Sometimes, when the brain of a person who has died from dementia is examined, features of Alzheimer’s disease and many tiny infarcts are found. It may be impossible to decide whether the patient’s symptoms were caused by Alzheimer’s disease or vascular dementia, so such people are said to have suffered from a mixed dementia.
Dementia with Lewy bodies
This form of dementia seems to occur when tiny deposits of protein called Lewy bodies build up in the nerve cells of the brain, disrupting its normal function. Scientists don’t yet understand why this happens. Some of the symptoms of dementia with Lewy bodies are the same as those of Alzheimer’s disease, such as memory loss and communication difficulties. But people with this type of dementia also frequently have symptoms of Parkinson’s disease so that their limbs tremble and their muscles are stiff. In addition, their mental abilities tend to fluctuate from one day to the next and they may have visual hallucinations.
Other causes of dementia
The list of causes in the box shows that dementia can occur for many reasons.
Frontotemporal dementia, sometimes known as Pick’s disease, is a rare form of dementia. Unlike other types of dementia, it is more likely to occur in people under the age of 65. Many of the people who develop it have a family history of the disease.
Sometimes the symptoms of dementia arise because of a metabolic or hormonal disturbance. For example, vitamin B12 deficiency, an underactive thyroid or, rarely, an adverse reaction to drug treatments can upset the balance of salts and chemicals in the blood and brain. If the dementia is caused by something like this, it can usually be treated successfully.
There are a large number of hereditary diseases that can also cause dementia. Fortunately these are all very rare.
Repeated head injuries, such as those suffered by professional boxers, sometimes result in the later development of a form of dementia.
If you want to find out more about Alzheimer’s disease, vascular dementia or the other rare causes of dementia, turn to page 59 where we recommend some books that you may find helpful.
WHAT SHOULD YOU DO?
If you are concerned that someone close to you is showing symptoms similar to those just described, you should seek medical advice. There are several reasons why you should take action sooner rather than later. First, it can be quite difficult to diagnose dementia correctly. The symptoms that are worrying you may have another explanation. One illness that often produces symptoms very similar to dementia, particularly in elderly people, is depression. You probably think of depression in terms of feeling low in spirits and pessimistic about the future, but clinical depression means much more than the temporary gloominess that we all feel occasionally. People suffering from severe depression may show so much difficulty with memory and concentration and loss of interest in their surroundings that they appear to be suffering from dementia.
A second reason for talking to your doctor is that some illnesses that produce symptoms of dementia can be cured and it is important to diagnose these as early as possible. Even if the condition is incurable, treatment may be available that will stop the symptoms getting worse. Last, if it does turn out to be a form of dementia for which there is no treatment, there is still much that can be offered in the way of practical help and support to improve the quality of life of the sufferer, and to ease the burden of those who care for them.
