NEFL and Cognitive impairment: To capture NfL dynamics in vivo, we analysed CSF and donated brain tissue from study participants from three neurodegenerative SILK cohorts: TANGLES (CSF and post-mortem brain in primary tauopathies), normal pressure hydrocephalus (NPH) SILK (CSF and ex vivo brain tissue from NPH patients), both summarized in Table 1; and a SILK cohort of cognitively normal individuals or with mild cognitive impairment (MCI; CDR ≤ 0.5), summarized in Table 3.