To assess the ability of 5 cerebrospinal fluid (CSF) biomarkers to differentiate between common dementia and parkinsonian disorders.

CSF NFL differs among different neurodegenerative diseases and is especially high in dementias engaging subcortical brain regions, such as VaD and mixed AD and VaD, but also in frontotemporal dementia. The association of high CSF NFL levels with disease severity and short survival supports the notion that high CSF NFL levels indicate more aggressive disease processes.