NEFL and Alzheimer disease: Measured CSF biomarkers included Alzheimer’s disease-related proteins: beta-amyloid isoforms (Aβ38, Aβ40, and Aβ42), total tau, tau phosphorylated at amino acid 181 (p-tau), glial fibrillary acidic protein (GFAP), and neurofilament light chain, as well as orexin, albumin (also measured in serum), and osmolality.