ABSTRACT
This chapter suggests that dementia may be less common in rural than in urban areas, and some types of dementia may be more common in some countries. It helps to have an account from a relative or other informant if one suspects dementia. As dementia progresses, the patient's own awareness and ability to give a clear history diminishes. Dementia can be divided into two main categories. Those conditions where the dementia is reversible include dehydration, vitamin B deficiency due to poor nutrition or secondary to alcohol abuse, hypothyroidism and head injury. Delirium in acute illness, after surgery, or associated with sleep deprivation can be confused with dementia, but tends to be of shorter duration and relieved by correction of the precipitating event. A small proportion of people with dementia have an underlying abnormality, such as a brain tumour, that when treated improves cognitive function. Sometimes depression and dementia are confused, particularly in people who become withdrawn and inactive.
