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Definition: Alzheimer's disease from Philip's Encyclopedia

Degenerative condition characterized by memory loss and progressive mental impairment; it is the commonest cause of dementia. Sometimes seen in the middle years, Alzheimer's becomes increasingly common with advancing age. Many factors have been implicated, but the precise cause is unknown.


Summary Article: Alzheimer's Disease
from Black's Medical Dictionary, 42nd Edition

A progressive degenerating process of neural tissue affecting mainly the frontal and temporal lobes of the BRAIN in middle and late life. There is probably a genetic component to Alzheimer's disease, but early-onset Alzheimer's is linked to certain mutations, or changes, in three particular GENES. Examination of affected brains shows ‘senile plaques’ containing an amyloid-like material distributed throughout an atrophied cortex (see AMYLOID PLAQUES). Many remaining neurons, or nerve cells, show changes in their NEUROFIBRILS, which thicken and twist into ‘neurofibrillary tangles'. First symptoms are psychological with gradually increasing impairment of recent memory and disorientation in time and space. This becomes increasingly associated with difficulties in judgement, comprehension and abstract reasoning. After very few years, progressive neurological deterioration produces poor gait, immobility and eventual death. When assessment has found no other organic cause for an affected individual's symptoms, treatment is primarily provision of appropriate nursing and social care, with strong support being given to the relatives or other carers, for whom looking after sufferers is a prolonged and onerous burden. Proper diet and exercise are helpful, as is keeping the individual occupied. If possible, sufferers should stay in familiar surroundings, with day-care and short-stay institutional facilities a useful way of maintaining them at home for as long as possible.

TRANQUILLISERS can help control difficult behaviour and sleeplessness but should be used with care. Recently drugs such as DONEPEZIL and RIVASTIGMINE, which retard the breakdown of ACETYLCHOLINE, may check - but not cure - this distressing condition. About 40 per cent of those with early or mild DEMENTIA may be helped by slowing down the progression of the disease.

Research is in progress to transplant healthy nerve cells (developed from stem cells) into the brain tissue of patients with Alzheimer's disease with the aim of improving brain function.

The rising proportion of elderly people in the population is resulting in a rising incidence of Alzheimer's, which is rare before the age of 60 but increases steadily thereafter, so that 30 per cent of people over the age of 84 are affected.

Copyright © A & C Black Publishers Ltd

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