We tested the effect of ApoE ε4 allele on cognitive decline in our study cohort by assessing the significance of ApoE:time interaction term and found that ApoE ε4 carriers exhibit significantly greater declines in MMSE, FAQ, CDR, GDS, and ADAS-cog11 and ADAS-cog13 compared to ApoE ε4 non-carriers over the study period (p < .05). This evidence concerns the gene APOE and Mental deterioration.