MAPT and dementia: The first set includes blood neuropathological biomarkers (e.g., decreased amyloid beta 42 [Aβ42] or ratio of Aβ42/Aβ40 and increased phosphorylated tau [p-tau]) that differentially reflect AD pathology [4, 5] and associated neurodegeneration [6], which have also been demonstrated to be associated with cognitive impairment or dementia [6, 7].