In sensitivity analyses, using the slopes of MMSE scores to measure cognitive decline, we found very similar mediating effects of tau aggregation (for mediating effects of the connectivity-based β-value: c’-c = −0.09 [95% CI −0.19, 0.00], p = 0.04; for mediating effect of the tau-PET rate of change in Q1: c’-c = −0.25 [−0.39, −0.13], p < 0.001). This evidence concerns the gene MAPT and Mental deterioration.