The frontal lobe is the part of the brain that controls certain aspects of our personality, particularly keeping our behaviour in check. Some forms of frontal lobe damage will lead to uninhibited behaviour, for example when a person has drunk too much alcohol. It seems as if alcohol is a stimulant, but in fact it depresses those parts of the frontal lobe that control behaviour, releasing inhibitions.
One of the features of Alzheimer’s disease that is said to differentiate it from the dementia that is characteristic of small strokes, is the change in personality often noticed in the Alzheimer’s sufferer. This can take the form of being unusually irritable or apathetic, or showing a lack of concern about matters that would formerly have been of importance to the sufferer, such as the management of the family finances. In the early stages the subject may realize that forgetfulness is a problem, but it may cause no undue anxiety; in some cases, however, the realization may be accompanied by considerable anxiety. It is usually relatives or friends who are responsible for alerting the doctor to the fact that something is wrong. Sometimes mood is very unstable, with anger or tears suddenly appearing for no obvious reason. This, however, is also a feature of the dementia that is caused by small strokes. As the disease progresses, restless wandering may occur and later becomes particularly troublesome at night. Eventually there is an almost complete disintegration of personality, with a lack of interest in personal hygiene, standards of dress, and occasionally the development of unpleasant behavioural habits -including going to the toilet in inappropriate and embarrassing places.
Many sufferers from Alzheimer’s disease lose things and accuse others of having stolen them. This paranoid behaviour sometimes progresses to the stage where it is imagined that others are plotting or planning against them, especially if there has been any talk of alternative accommodation. Hallucinations may also occur and these may take the form of the sufferer seeing people or objects that are not really there or, less occasionally, being told to do things by voices from uncertain sources.
As mentioned earlier, another feature of Alzheimer’s disease is the development of difficulty with speech. Speech and language functions are controlled by special centres in different parts of the brain, not just the frontal lobe, but will be considered here for convenience.
The most important language disorder is difficulty with names. This can take two forms. The names of common objects may be forgotten so that when a pen is required, it will be referred to as ‘that thing you write with’ and as the disease progresses even this way round the problem may not be possible, with the sufferer just pointing at an object and demanding that he or she be given it. Sometimes, however, a second type of difficulty with language occurs and this is not so much the naming of an object, but difficulty recognizing the name as used by somebody else.
There is a particular area of the left frontal lobe in most people that is responsible for the control of language and this is affected early on in the course of Alzheimer’s disease. Sometimes it isn’t noticed in the very early stages unless careful tests are undertaken. However, once the language disorder has become marked, it usually indicates that the disease is going to progress more rapidly than hitherto. Generally, difficulty in using the name of an object occurs earlier in the disease whereas difficulty in understanding the name of an object when somebody else uses the word occurs later.
One further aspect of frontal lobe function that is often abnormal in the later stages of Alzheimer’s disease is the reappearance of reflexes that are more typically found in young babies. If the palm of an infant is stroked with a finger, the finger will be seized. Because these reflexes occur early in life and disappear as the nervous system matures, they are referred to as primitive reflexes. When there is significant degeneration in the frontal lobes, the grasp reflexes and others reappear. Although they are occasionally present in apparently normal people throughout life, their presence in an Alzheimer’s sufferer usually indicates quite an advanced stage in the disease.
*27\138\2*
