The term dementia is a generic term for several diseases, summarizing a number of symptoms caused by different diseases of the brain which can affect cognitive performance and may lead to the decline of brain function in various ways. Primarily affected are memory, thinking, language, motor skills, orientation, decision and judgment and in some cases also the personality. Changes in the emotional control, the emotional state, social behavior, or motivation may be symptomatic concomitants.

According to the criteria of the International Classification System of the World Health Organization (ICD-10) for a diagnosis of dementia, the symptoms must have been present for at least six months. The onset is usually insidious. Although the elderly are often affected by dementia, it is still not part of normal aging.

With 60-80% Alzheimer is the most common form of dementia, followed by vascular dementia with about 20%, which is caused by blood flow disturbances in the brain – often after a stroke. However, other shapes such as e.g. the Lewy Körperchen- dementia , the Frontotemporal Dementia (Pick’s disease, which is characterized by personality changes, or mixed forms are possible.

Difficulty with short-term and long-term memory can but not necessarily lead to the conclusion that there is a dementia. Symptoms of dementia may be other underlying causes, such as, inter alia, Depression, delirium, age-related forgetfulness, or even dehydration. Especially depression, which is the most common mental illness in old age in addition to dementia creates the impression of a dementing condition image by the apparent cognitive decline and is therefore referred to as „pseudo-dementia“. In contrast to dementia, memory problems vanish with the release of the depression again.