MAPT and Cognitive impairment: Among them, Aβ‐PET (A + T− subjects) is an independent reliable predictor of longitudinal cognitive decline in terms of ADAS‐13, ADNI‐MEM, and MMSE scores rather than tau pathology (A − T+ subjects), indicating tau accumulation is not closely correlated with future cognitive impairment without being driven by Aβ deposition.