Biomarkers and diagnosis of dementia with Lewy bodies including prodromal: Practical aspects.

Dementia with Lewy Bodies (DLB) is a common form of cognitive neurodegenerative disease. More than half of the patients affected are not or misdiagnosed because of the clinical similarity with Alzheimer's disease (AD), Parkinson's disease but also psychiatric diseases such as depression or psychosis. In this review, we evaluate the interest of different biomarkers in the diagnostic process: cerebrospinal fluid (CSF), brain MRI, FP-CIT SPECT, MIBG SPECT, perfusion SPECT, FDG-PET by focusing more specifically on differential diagnosis between DLB and AD. FP-CIT SPECT is of high interest to discriminate DLB and AD, but not at the prodromal stage. Brain MRI has shown differences in group study with lower grey matter concentration of the Insula in prodromal DLB, but its interest in clinical routine is not demonstrated. Among the AD biomarkers (t-Tau, phospho-Tau181, Aβ42 and Aβ40) used routinely, t-Tau and phospho-Tau181 have shown excellent discrimination whatever the clinical stages severity. CSF Alpha-synuclein assay in the CSF has also an interest in the discrimination between DLB and AD but not in segregation between DLB and healthy elderly subjects. CSF synuclein RT-QuIC seems to be an excellent biomarker but its application in clinical routine remains to be demonstrated, given the non-automation of the process.