The diagnosis of dementing disorders is severely hampered by the absence of 
reliable biomarkers that can be measured in body fluids such as blood, urine and 
cerebro-spinal fluid (CSF). Searching for biomarkers is hampered by the huge 
variability between individuals; the use of autopsy specimens induces 
significant data fluctuation due to rapid post-mortem changes in the specimens. 
The search for biomarkers obtained from living donors has contributed already a 
vast amount of data. The role of amyloid and tau as early diagnostic markers in 
the pathology of dementia has been reported in differential involvement in 
Alzheimer's disease (AD), late onset Alzheimer disease (LOAD), Lewy Body 
dementia (DLBD), Vascular dementia, fronto-temporal lobar degeneration (FTLD), 
Mild cognitive impairment (MCI) and non neurological controls. In the coming 
decennia, brain/tissue/biobanks (BTB-banks) will have a major role in 
identifying the relevant biomarkers and will collect, preserve and type RNA and 
DNA extracted from brain/tissue/body fluids in order to update the pathological 
hallmarks of dementing disorders. The present paper reviews and compares the 
currently known/clinically applied biomarkers in dementia which can be 
identified and incorporated into clinical drug trials and elucidate proposed 
mechanisms of disease and drug action. Furthermore, the review screens a panel 
of biomarkers used for early and differential diagnosis and comments on the 
validity of these biomarkers in reflecting the typical hallmarks of neurological 
disorders.