Classification and diagnosis of dementia: a mechanism-based approach

Dementia is an acquired disorder of the brain, designating an impairment of established mental functions due to various aetiologies, representing a decline from pre-morbid level which is severe enough to impair normal daily functioning. Classification of dementias is commonly based on individual aetiological categories, more recently molecular-pathological classifications have been proposed for degenerative dementias. This article is an attempt to provide a comprehensive, yet simplified classification of dementias following a mechanism-based approach. A systematic approach to diagnostic work-up is also proposed based on this classification.