NEFL and Alzheimer disease: The median serum NfL level in the AD SCA patients was 109.5 pg/mL (70.1–154.9 pg/mL), which was significantly higher than that among the controls (median: 41.1 pg/mL, 32.3–57.1 pg/mL) (p-value < 0.001) (Fig. 1a, Table 2).