In their longitudinal study, which included PET measurements with FDG PET and amyloid tracers, they showed that the plasma NfL increase occurred almost 10 years before fibrillary Aβ deposition was detectable by PET and was one of the first biomarkers to change by age 28–30 years, more than 20 years before prodromal AD diagnosis [13]. Here, NEFL is linked to Alzheimer disease.