NEFL and Alzheimer disease: ,6 NfL and phosphorylated NfH (pNfH) are significantly elevated in ALS,7, 8, 9, 10, 11, 12 with NfL extensively studied in AD,13, 14, 15 frontotemporal dementia (FTD),16, 17, 18 and Lewy body dementia (LBD),19,20 correlating with cognitive decline and neurodegeneration.