Although diagnosis is often most easily made with the help of a brain scan, the outwardly discernible character of the disease provides many clues to its presence.
As discussed, the disease will often have an abrupt onset and there will be gradational deterioration with a fluctuating course; although a person with multiple infarct dementia will suffer from an intellectual decline that is in many ways similar to that associated with Alzheimer’s disease, to begin with the disease will pick out different areas of intellect, resulting in a rather patchy intellectual loss compared with the steady and relentlessly progressive deterioration that is seen in most of the other conditions that cause dementia. Personality is often preserved until quite late in the disease, as is insight, and this can result in severe depression. People with MID are often very unstable emotionally.
There is often evidence of an underlying medical condition that puts the patient at particular risk of having strokes, such as high blood pressure or heart disease. If some of the small strokes have affected the part of the brain controlling the face or the limbs, there will be signs of this when the subject is examined by a doctor. The following account describes a fairly typical case history.
Mrs Brown
Mrs Brown was sixty-eight when her husband took her along to their general practitioner because he was worried about his wife’s forgetfulness. It was clear that she had been becoming more and more forgetful and that this had started suddenly, after she had experienced a ‘dizzy turn’ on Christmas Eve. Although she had never lost consciousness, she had had several more funny turns after most of which she was a little confused for a day or two. The doctor knew that Mrs Brown suffered from diabetes and needed to take tablets, so he checked the level of sugar in her blood. This was normal and she didn’t have any of the other symptoms of high blood sugar. He therefore examined her carefully and discovered that she had a high blood pressure. He treated this with the appropriate medicines.
When he saw her again a month later, Mrs Brown was still very forgetful, had some difficulty with her speech, and needed a little help with dressing. This was only a little better than her condition when he had seen her a month previously.
A further year passed during which Mrs Brown was seen on several occasions by her doctor, who ensured that her blood sugar level and her high blood pressure were properly treated. During this year she only had one further dizzy spell, after which she had again become a little more confused. Although there was some recovery over the ensuing two or three days, she was a little more muddled than before.
In summary, Mrs Brown had some of the characteristic features of multiple infarct dementia and careful attention to the underlying risks — the blood sugar level and the high blood pressure – had probably slowed down the rate of intellectual deterioration.
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