[Searching for biomarkers to diagnose dementia]

A decrease in the concentration of amyloid beta-protein-42 and an increase in that of tau or phosphorylated tau in addition to volumetry on MRI and amyloid imaging by PET are available biomarkers. However, we need better biomarkers to detect very early stage of Alzheimer disease to develop disease modifying drugs, which should be used 10 or 15 years prior to emergence of clinical symptoms. In terms of biomarkers for other dementing neurodegenerative diseases, including synucleinopathies such as dementia with Lewy bodies and multiple system atrophy, and tauopathies such as progressive supranuclear palsy, corticobasal degeneration, synuclein, TDP-43, progranulin and tau may be candidate proteins for possible biomarkers for these diseases.