NEFL and Alzheimer disease: pTau181, pTau231, and NfL were significantly higher in AD converters compared with CU at symptom onset only (1.63 pg/mL (0.73), p = 0.025); (1.65 pg/mL (1.21), p = 0.049); (3.56 pg/mL (1.65), p = 0.032) respectively.