NEFL and Alzheimer disease: A large number of clinical studies have consistently shown that NfL, Aβ40, Aβ42, and p-tau181 in CSF and plasma are the key factors with predictive value for early AD detection (Agarwal and Tripathi, 2011; Schoonenboom et al., 2012; Olsson et al., 2016; Hampel et al., 2018; Paquet et al., 2018).