MAPT and Cognitive impairment: First, we found that the relationship between Aβ pathology and cognitive impairment was partially mediated by baseline tau pathology (CSF p-tau, 26.15% of total effect) and neurodegeneration (CSF t-tau, 16.6% to 36.4% of total effect; whole brain volume, 16.5% to 24.1% of total effect; hippocampus volume, 17.3% to 32.9% of total effect; entorhinal volume, 14.8% to 21.3% of total effect; and mid temporal volume, 23.1% to 47.0% of total effect) (Fig. 3).