The diagnosis of dementia disorders can be made in several steps. The
symptomatology, severity and course of the illness must be considered.
Memory disturbances must be present. Ante-mortem classification of de
mentias is based on known or assumed etiology. The final step is the p
ost-mortem diagnosis. Of the primary dementias, Alzheimer-type dementi
a is the most important group, Accumulating data indicate that this fo
rm can be divided into subgroups. The concept of multi-infarct dementi
a (MID) should not be used synonymously with vascular dementia, which
is a broader concept, Vascular dementias can also be divided into subg
roups, Dementia is an advanced stage of a brain disorder. It seems imp
ortant to identify brain disorders before they have reached the advanc
ed level of dementia. A name for such disorders is dysmentia.