APOE and hippocampal atrophy: However, some more recent reports argued that CSF_Tau is crucial for predicting cognitive decline and for the diagnosis of early-MCI, and that its alterations appear to begin even earlier than hippocampal atrophy or cognitive decline signs, especially when looking at APOE4 carriers, who showed elevated values of CSF_Tau already in the prodromal AD stage [57–60].