Table 3.

Putative correspondence between neuropathological and biomarker similarities in Parkinson’s disease and Alzheimer’s disease

Neuropathology	Biomarker finding
Loss of pre and/or postsynaptic integrity, including dendritic spines	CSF levels of specific synaptic proteins (SNAP25, synaptotagmin, neurogranin)
Small protein aggregates with non-conventional approaches as PET blot, PAF assay or array tomography	CSF levels of α-synuclein or Aβ or phosphorylated tau
Larger protein aggregates by traditional immunohistochemistry	PET imaging of Aβ
Neuromelanin and other potential off-target binding structures to be considered	PET imaging of tau (PET imaging of α-synuclein when it becomes available?)

Aβ, amyloid-β; CSF, cerebrospinal fluid; PAF assay, protein aggregate filtration assay; PET blot, paraffin-embedded tissue blot; PET imaging, positron emission tomography imaging.