NEFL and Mental deterioration: Although it has been demonstrated that plasma NfL, an important protein component of the neuronal axon cytoskeleton, could be a sensitive biomarker for neurodegeneration and predict cognitive decline in many central nervous system diseases, such as AD, FTLD and VaD (Forgrave et al., 2019; Aamodt et al., 2021), there is no evidence for the contribution of Met to NfL level.