|
|
|||||||||||||||||||||||||||||||||
|
|
Welcome to the UK's Healthcare Law Service |
 |
|
Guest Experts’ Corner |
|
By Dr Geoffrey Phillips Contrary to popular opinion, most older people, including the very elderly, have no significant cognitive impairment. Cognition is the process by which knowledge is acquired and includes perception, intuition and reasoning. Increasing age is, however, associated with slower information processing and memory retrieval but even this is not universal and even when present, is not so severe as to interfere with day-to-day functioning. The perceived importance of information and its emotional associations will tend to aid memory storage and recall. Accuracy of recall is given preference over speed, but keeping track of more than one thing at a time and rapidly understanding complex material tends to become more difficult and can be further aggravated if vision and hearing are in any way impaired. Dementia, by contrast, is a specific medical condition defined as an acquired global impairment of intellect, memory and personality, which is progressive in nature. This leads to a decline in the ability to perform daily activities, as well as to behavioural changes. Dementia is not considered to be caused by senility, though it does become increasingly common with advancing age. About 10% of people aged 65 years or older, have evidence of mild cognitive impairment and nearly 15% of them go on to develop a dementing illness each year. Between 20 and 25% of people over the age of 80 years suffer from a dementing illness.In a dementing illness, a decline in memory, especially in the learning of new material, is characteristic but the earliest changes often occur within the cognitive field, ie, perception, intuition and reasoning. Typically, patients forget names, and dates, mislay items and lose the thread in conversation or letter writing. In the early stages of dementia patients may seem quite normal, especially if assessed within a familiar environment or given tasks to perform of which they are familiar. Although memory impairment is characteristic of dementia, the true extent of memory loss in dementia may be effectively disguised by a confabulatory response to questions. In effect, this is the painting in of the blank spaces in the memory with plausible responses. In the early stages of a dementing illness, it is thus possible, without performing specific tests of mental function, to assume that individuals are in full possession of their mental faculties.The global impairment of intellect, which is the essence of a dementing illness effects personality, logic understanding, memory and behaviour, with consequent loss of judgment. These parameters deteriorate in no set order. There is deterioration in thinking, planning, organising and the general processing of information. There is occasionally disinhibition, which may manifest itself in increased belligerence but more usually, patients suffering from dementia are increasingly less resistant to outside pressures and may be readily manipulated and vulnerable to both well meaning and malevolent exploitation.One would normally assess the full extent of cognitive impairment by means of the mini mental state examination, which is a set of well-validated questions, giving a maximum score of 30. Scores below 24 are increasingly suggestive of significant cognitive impairment. A more simple abbreviated mini mental test is sometimes used, scoring out of 10 simple questions. Hallucinations may occur, especially late in the illness but are not a predominant feature. In clinical practice, the diagnosis of dementia is rarely made until the disease has been apparent for 6 or more months. Typically the patient will attend hospital accompanied by a relative who gives a history of intermittent odd behaviour, a change in personality, forgetfulness and the inability to perform complex tasks or follow a complicated television play. There will usually be, if specifically asked for, a history of losing keys, bus pass, spectacles etc, and very often a history of burning saucepans, or leaving gas fires on after bedtime. By contrast the patient is usually unaware of any problem and will usually deny the truth of what the relative says. In advanced dementia, there are physical features, which can be summarised as a reversal of the developmental features, which occur during the first year or so of a baby’s life. The ability to speak deteriorates and is eventually lost, the ability to walk declines and ultimately, even the ability to swallow deteriorates, with the associated risk of food, and particularly fluids entering the airways, causing pneumonia. Fluids are handled better if thickened with proprietary thickening agents but further progression of a dementing illness can render even this unsafe. Medical opinion is somewhat divided as to whether, in such circumstances, it is appropriate to progress to artificial tube feeding. TYPES OF DEMENTIA Alzheimer’s Disease Most dementia seen is of Alzheimer type, accounting for approximately 75%. This condition typically occurs in elderly females and has a characteristic slow progressive course, which is predictable. Vascular Dementia Roughly 20% of dementing illness is the result of vascular or so called multiinfarct dementia. This disease is characterised by a succession of small and clinically imperceptible strokes, which together, over a period of time, gradually destroy parts of the brain leading to cognitive impairment. There is often, but not always, a history of previous stroke or other hallmarks of vascular disease, such as a heart attack, poor circulation to the legs or other evidence of arterio-sclerosis. There may be a background of high blood pressure or diabetes, both of which, along with tobacco and alcohol abuse, predispose to the development of vascular disease. When present, vascular dementia, which can have an abrupt onset, is characterised by a stepwise decline, with sudden intellectual deterioration (due to the latest small stroke), followed by a period of intellectual stability or slight improvement before relapsing again with the onset of a further infarct. It is of course possible for vascular dementia to coexist with Alzheimer’s disease, producing a mixed picture clinically with a rather haphazard and unpredictable rate of progression.Lewy Body Dementia Lewy body dementia is similar in its progression to Alzheimer’s disease but patients often exhibit tremor and stiffness of movement, suggesting that there may be an element of Parkinson’s disease. Hallucinations, which may be vivid and distressing, are a feature of Lewy Body Dementia and occur out of proportion to the cognitive deficit. Well meaning trials of treatment with antiparkinsonian drugs can make such hallucinations much worse. Picks Disease This condition, also known as fronto-temporal dementia has features of slow progressive cognitive impairment, with a disproportionate amount of slovenliness, which manifests itself in deterioration in personal hygiene. Other Causes of Hallucination Visual and auditory hallucinations, ie, seeing images and hearing, particularly voices which are not real, are generally features of mental illness, rather than dementia. They may occur as the result of a delirium brought about by physical illness, in which case they settle as the physical illness improves. People with visual impairment occasionally experience florid and frightening visual hallucinations without associated mental illness. This is known as the Charles-Bonnet Syndrome and is the result of the visual cortex of the brain, spontaneously creating images as a result of being under-stimulated. Patients are often frightened that they are developing a mental illness and usually, reassurance is sufficient, though there are medications, which may help. ©
Dr Geoffrey Phillips |
|
|
||||
|
||||