Alzheimer’s disease is probably the most difficult of the dementing illnesses to distinguish from the changes of normal ageing. As mentioned before, there is indeed some degree of memory impairment in many people as they grow older although this may not be as great as was once imagined. As the earliest sign of Alzheimer’s disease is often exaggerated memory loss, there is often a grey area in the interpretation of tests of memory function. It is therefore often necessary to test memory function on successive occasions over several months before one can be certain whether or not Alzheimer’s disease is present.
There are many tests of intellectual function; some are very long and complicated and others are simple and quick. As one might expect, the shorter and simpler the test, the more likely it is that the information will be unhelpful or inaccurate. Nevertheless because of the time involved, the initial tests often have to be the short and simple ones. Many of these are employed by district nurses, health visitors, and doctors when they first meet a person with suspected dementia. The tests usually involve a few questions that are designed to gauge different types of memory function — the ability to use language correctly and parietal lobe function. The performance of more complicated tasks such as the ability to carry out simple calculations may also be examined. In many ways these are most useful if the results are normal. An abnormal result will not diagnose dementia; on the contrary, it will indicate that something is wrong and that further assessment is required. In difficult cases the patient will need to be referred to a qualified psychologist who will perform the more extensive and sensitive tests. These will usually go a long way towards determining whether or not dementia is present, and may also provide information that will help in deciding which condition may be causing the dementia.
Nowadays many of these tests have been put on to computer; colourful images on a television screen help to keep the attention of the person being tested and reduce the opportunity for inaccurate responses to creep in because of adverse interactions between the patient and the person doing the testing.
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