Classification of Dementia
The word ‘Dementia’ is derived from Latin, de-men-tia. De means away from, men means the mind, and tia is to the state. Dementia is a type of brain disease that results in memory and cognitive problems in patients; it is also characterized by degenerating functions of patient emotion, language and behavior. It can result in degeneration of the personal life, but the individual can still be physically maintained.
Sixty-five years old is used as the disease onset time boundary. If onset occurs before 65 years old, it is referred to as presenile dementia; if the onset occurs after 65 years old (including 65), it is referred to as senile dementia. Most patients have dementia in the senile stage. Smith (2013) believes that dementia is characterized by persistent changes in senile mental changes.
Current studies show that brain damage, aging and disease are the causes of dementia, which results in mental function degrading at a faster than typical rate at that age. Dementia is not one disease but rather a group of similar clinical manifestations of disease clusters.
Dementia can be divided into three types based on its cause: degenerative dementia, vascular dementia and post-traumatic dementia. Degenerative dementia includes Alzheimer's disease, front temporal dementia and Lewy body dementia. Vascular dementia is caused by cerebral vascular disease, and traumatic dementia is caused by a head trauma.
According to lesion location, dementia can be divided into cortical dementia and subcortical dementia. In cortical dementia (Corsellis, 1962), including Alzheimer's disease, the lesion is detected in the cerebral cortex. In subcortical dementia (Albert, 1974), the lesion area is detected in the cortex of the brain, such as in Parkinson's disease and Huntington's disease. In limbic dementia, the lesion area is detected in the limbic system (Gascon, 1973).
According to the possibility of cure, dementia can be divided into reversible and irreversible dementia. Some types of dementia can be cured, for example, when dementia is caused by a lack of vitamins or cancer. However, only approximately 5% of patients have reversible dementia. Most patients have irreversible dementia, which can only be prevented and relieved.