[Dementia: classification, diagnosis--in search of treatable causes].

There are so many possible etiologies of dementia that its evaluation must be well directed. The neuropsychological examination permits the diagnosis of dementia and allows for a classification of a dementia as 'cortical' dementia, i.e. with aphasic, apraxic or agnosic disturbances, or 'subcortical' dementia, which is mainly characterized by psychomotor retardation. Virtually all treatable dementias present as 'subcortical' dementia. The search for a cause of a dementia includes the clinical setup and a number of additional examinations, which may reveal causes that were not suspected on clinical grounds. In this paper we propose a classification of dementias based on the distinctions 'cortical/subcortical dementia' and 'somatic neurological examination normal/abnormal'. Furthermore, we suggest an array of additional examinations which in our view should be performed in any case of dementia.