An acquired and irreversible deterioration in intellectual function due to progressive brain disease. Around 10 per cent of people aged over 65 and 20 per cent of those aged 75 or over are affected to some extent and it is estimated there are over 850,000 persons in the UK currently with this disorder. It appears gradually as a disturbance in problem-solving and agility of thought which may be mistakenly interpreted as due to tiredness, boredom or DEPRESSION. As memory failure develops, the affected person becomes bewildered, anxious and emotional when dealing with new surroundings and complex conversations. Catastrophic reactions are usually brief but are commonly associated with an underlying depression, which can be mistaken for progressive apathy. The condition progresses relentlessly with loss of recent memory extending to affect distant memory and failure to recognise even friends and family. Physical aggression, unsocial behaviour, deteriorating personal cleanliness and incoherent speech tend to develop. Similar symptoms to those of dementia can occur in curable conditions including depression, INTRACRANIAL tumours, SUBDURAL haematoma, SYPHILIS, vitamin B1 deficiency (see APPENDIX 5: VITAMINS) and repeated episodes of cerebral ISCHAEMIA. This last may lead to multi-infarct dementia.
(See also ALZHEIMER'S DISEASE and FRONTOTEMPORAL DEMENTIA.)
If organic disease is identified, it should, where possible, be treated; otherwise the treatment of dementia is alleviation of its symptoms. The affected person must be kept clean and properly fed. Good nursing care in comfortable surroundings is important and sedation with appropriate drugs may be required. Patients may eventually need institutional care. (See ALZHEIMER'S DISEASE.)