Figure 3.

Temporal lobe atrophy is associated with APOE ε4 status and diagnostic group in E-MCI and HC participants. A significant effect of diagnosis on neurodegeneration in the temporal lobe was observed (p < 0.05), including in hippocampal volume (A) and grey matter (GM) density (B), mean temporal lobe cortical thickness (C), and mean temporal lobe GM density (D). In all evaluated regions, E-MCI participants showed more temporal lobe atrophy than HC participants. In addition, APOE ε4 status was significantly associated with mean temporal lobe GM density, with APOE ε4− participants showing smaller mean temporal lobe GM density than APOE ε4+ participants. Finally, a significant interaction effect of diagnosis and APOE ε4 status was observed in mean temporal lobe cortical thickness, with ε4− HC participants showing thicker mean temporal lobes than all other groups. All analyses were covaried for age, gender, education, handedness, and total intracranial volume (ICV). The total number of participants for each analysis is indicated on each graph (Panels A–D). Note: Thirteen participants were excluded from the GM density analyses, but not the cortical thickness and volumetric analyses, for failed VBM segmentation (3 HC ε4−, 2 HC ε4+, 4 E-MCI ε4−, 4 E-MCI ε4+).