An acquired and irreversible deterioration in intellectual function. Around 10 per cent of people aged over 65 and 20 per cent of those aged 75 or over are aﬀected to some extent. The disorder is due to progressive brain disease. It appears gradually as a disturbance in problem-solving and agility of thought which may be considered to be 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. In professional skilled workers this is frequently ﬁrst recognised by family and friends. 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 commonly develop. Similar symptoms to those in 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.
Treatment 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.)