NEFL and amyotrophic lateral sclerosis: NfL levels were measured in 105 ALS patients (33.4%) at a median time from symptom onset of 11.0 months (IQR 6.0–21.0), with a mean concentration of 128 pg/ml (SEM \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\pm$$\end{document}± 8).