NEFL and Mental deterioration: Building on this work by applying the recent Aβ (A), tau (T), and neurodegeneration (N) classification system (Jack et al, 2016, 2018) to plasma AD biomarkers (Cullen et al, 2021a), a model combining P‐tau181 and NfL—but not Aβ42/Aβ40—was found to best predict cognitive decline (MMSE) and progression to AD dementia over a period of 4 years.