NEFL and Alzheimer disease: Regarding the representative blood biomarkers, plasma levels of p-tau 217 (174.14 ± 89.20 vs. 276.31 ± 128.37, p < 0.0001) and NfL (532.64 ± 189.28 vs. 851.93 ± 344.70, p < 0.0001) in AD group were significantly higher than those in CN group, respectively (Table 1 and Figure 1).