Significant differences in the CSF concentrations of the ATN biomarkers (CSF Aβ1–42, CSF t-Tau, CSF p-Tau181, and CSF NFL), plasma NFL, plasma Aβ1–42, and combination biomarkers (CSF NFL/Aβ1–42 and plasma NFL/Aβ1–42) were noted between all AD continuum groups and the CN Aβ- group (Figure 1a–h and Table 1). Here, NEFL is linked to Alzheimer disease.