BackgroundAlzheimer's disease (AD) involves Aβ and tau pathology, initiating years before symptoms. the apolipoprotein E ε4 allele (APOE ε4) is the major genetic risk factor, influencing neurodegeneration and functional network disruption. This study investigates how APOE ε4 modulates the default mode network (DMN)'s hierarchical organization to accelerate cognitive decline.ObjectiveThis study aimed to elucidate how APOE ε4 accelerates AD pathological progression by altering the functional gradi...