MAPT and Cognitive impairment: Despite the potential contribution of these pathologies to cognitive impairment, the frequency and clinical relevance of co-existing ADNC and non-ADNC pathologies have not been rigorously investigated in the context of CSF Aβ and tau biomarkers, particularly among CSF A + individuals with a low phosphorylated tau burden (i.e., discordant CSF A + T −) compared to CSF A + cases with a high tau burden (i.e., concordant CSF A + T +).