NEFL and frontotemporal dementia: In patients classified as prodromal and mild FTD, we observed significant higher levels of serum NfL in patients who converted to mild or moderate dementia, respectively: average difference of 14.0 (95% CI 6.3 to 21.6 pg/mL), p = 0.001 in prodromal FTD; average difference of 26.4 (95% CI 9.1 to 43.7 pg/mL, p = 0.004 in mild FTD (see Fig. 3B).