What is dementia?

Dementia is a descriptive term derived from the Latin root de mens, indicating an observable decline in mental abilities. It is an acquired clinical syndrome characterised by deterioration of mental functioning in its cognitive, emotional and conative aspects. The concept is comprehensive with several different clinical profiles and courses. The diagnosis of dementia implies that several mental faculties are involved and exclude isolated neuropsychiatric disturbances such as amnesia and aphasia which occur with focal brain lesions. Description and classification of dementia conditions have however to deal with the problem that the word "dementia" might have different meanings in different contexts. It might denote a clinical syndrome irrespective of etiology, but also imply that the etiology of this syndrome is brain dysfunction. Moreover, the term dementia is sometimes used in a wider sense to describe the underlying brain disease from its early subtle manifestations to advanced stages of severe deterioration. By definition this deterioration previously was progressive and irreversible with little hope for the patient. Clinical experience however has changed our views, and it is now accepted that the course of dementia can be progressive, static or remittent.