[On the etiology of syndromes of dementia (author's transl)].

Some new aspects of dementia are discussed. It is emphasized that the idea of dementia as a primary entity is obsolete. The following classification is proposed: dementia as a sign of a (still) unknown illness; dementia is a sign of a known, but not yet treatable illness and dementia as a sign of a known and also treatable illness. The differential diagnosis of the last group is described. Finally, some tests are proposed for the examination of demented patients to diagnose early treatable illnesses.