In particular, the absolute theta power of channel O2 was negatively correlated with Aβ42 (r = −0.358, p < 0.001) and positively correlated with p-tau (r = 0.442, p < 0.001), indicating that stronger low-frequency oscillation at the occipital cortex was linked to lower Aβ42 and higher p-tau amount in patients with MCI and AD. This evidence concerns the gene MAPT and Alzheimer disease.