The main findings of our study were that (1) plasma NFL concentration and rate of change in plasma NFL were abnormally high in the preclinical phase of AD (2) plasma NFL was associated with some core AD-related biomarkers in the preclinical phase of AD (3) baseline plasma NFL played predictive roles in both impaired cognition and neuroimaging abnormalities, especially for the preclinical AD individuals (4) rate of change in plasma NFL showed predictive effects on neither of impaired cognition and neuroimaging abnormalities among CN individuals. This evidence concerns the gene NEFL and Alzheimer disease.