Different types of dementia

Dementia is defined by the World Health Organisation as “a syndrome due to diseases of the brain, usually of a chronic or progressive nature, in which there are disturbances of multiple higher cortical functions, including memory, thinking, orientation, comprehension, calculation, learning capacity, language and judgement. Consciousness is not clouded. The impairments of cognitive function are commonly accompanied, and occasionally preceded, by deterioration in emotional control, social behaviour or motivation.��? However, there is some variation in this definition in practice. For example, patients with dementia with Lewy bodies can experience variations in consciousness (see below). In addition, it is accepted that early stage dementia may be mild and, therefore, not fulfil the WHO criteria. Permission was not granted for electronic publication of this article. Please refer to the hard copy.