The invention relates to panels of biomarkers including proteins phosphatase 1 regulatory subunit 14A and/or 2′,3′-cyclic-nucleotide 3′-phosphodiesterase and/or phosphorylated tau or fragments thereof and methods using thereof for diagnosing, staging, treating and assessing the response of a treatment for a neurocognitive disorder characterised by tau toxicity, in particular for Alzheimer's disease. The present invention shows that the biomarkers disclosed herein are elevated in the brain of subjects with an advanced stage of a neurocognitive disorder (Braak stage V/VI) and/or are regulated in the CSF of AD subjects in comparison to cognitively affected non-AD controls; and/or regulated in response to two casein kinase 1 delta inhibitors.