NEFL and frontotemporal dementia: The same may apply to the absence of significant differences of CSF NFL levels in bvFTD compared to ODs in studies of both strata considered separately [28, 29, 31, 32], the other main reason here (not shared with the previous issue regarding FTD in general) being the inclusion of other FTD categories featuring slightly higher NFL levels than bvFTD, namely nfvPPA and especially svPPA [33, 34], in the group of ODs.