MAPT and Alzheimer disease: Interestingly, the score of patient KA at the “4 mountains test” (8/15) exactly replicated an earlier finding with that task in patient Jon, and also fits with the cut-off score of 8 or below for differentiating between Mild Cognitive Impairment patients with or without positive CSF biomarkers for AD pathology (i.e., levels of β-amyloid1-42 and phosphorylated tau) (Chan et al., 2016).