[Dementias: present situation and future perspectives (II). Biological markers].

In the previous paper, the first one in our trilogy about dementias, we introduce the concept and evaluate the diagnostic methods and the data provided by epidemiological investigation. In this paper we review the different biological diagnostic markers, based, in the first place, on the studies of neuroimage (computerized axial tomography, magnetic resonance, functional neuroimage techniques) and those properly neurophysiological; in the second place, the anatomopathological and physiopathological markers are examined; and, in the third place, those based on the modern genetic investigations. In the absence of an 'univocal biological marker', the current investigation about markers is on the way to the study of abnormal proteins discovered in the brain, of the modifications detected in the cellular metabolism, of the manifestations of the immunologic mechanisms and of the involved inflammatory processes, and is on the way to the advances and proximate perspectives of molecular genetics and animal models. Meanwhile, the diagnostic for the main dementia, due to Alzheimer's disease, is basically a clinic, exclusive and residual one, mainly in its initial stadium.