Fig. 2

Summary of anticipated biomarker results for the different clinical phenotypes of AD. Decreased plasma Aβ42/40 ratio is extended across all clinical phenotypes, as there is evidence of increased Aβ plaques across the phenotypes. Decreased plasma Aβ42/40 ratio has been identified across the AD continuum [26, 28]; however, further studies are warranted to investigate the utility of the Aβ42/40 ratio across the clinical phenotypes. Aβ, amyloid-beta; Aβ42/40 Aβ (1–42)/(1–40); AD, Alzheimer’s disease; BBBM, blood-based biomarker; CSF, cerebrospinal fluid; FDG, fluorodeoxyglucose; FTD, frontotemporal dementia; MRI, magnetic resonance imaging; PET, positron emission tomography; pTau, phosphorylated tau; tTau, total tau