NEFL and amyotrophic lateral sclerosis: We observed a significantly reduced survival in ALS patients with Nf‐L and Nf‐H concentrations above the median and Q3 (above median p = 0.0011 for Nf‐H and p < 0.0001 for Nf‐L, Fig. 4G and J; above Q3, p = 0.0018 for Nf‐H and p < 0.0001 for Nf‐L Fig. 4H and K; survival time from V1).