NEFH and Primary lateral sclerosis: The most relevant finding of the study lead by Zucchi et al. was that CSF and serum p-NfH can discriminate ALS with predominant UMN signs from other UMN syndromes, like hereditary spastic paraplegia (hSP) and primary lateral sclerosis (PLS); moreover, CSF p-NfH concentration may differentiate UMN syndromes from HC and are the most stronger predictors of survivals [9].