Effects of ApoE4 and maternal history of dementia on hippocampal atrophy

Abstract

We applied an automated hippocampal segmentation technique based on adaptive boosting (AdaBoost) to the 1.5 T magnetic resonance imaging (MRI) baseline and 1-year follow-up data of 243 subjects with mild cognitive impairment (MCI), 96 with Alzheimer's disease (AD), and 145 normal controls (NC) scanned as part of the Alzheimer's Disease Neuroimaging Initiative (ADNI). MCI subjects with positive maternal history of dementia had smaller hippocampal volumes at baseline and at follow-up, and greater 12-month atrophy rates than subjects with negative maternal history. Three-dimensional maps and volumetric multiple regression analyses demonstrated a significant effect of positive maternal history of dementia on hippocampal atrophy in MCI and AD after controlling for age, ApoE4 genotype, and paternal history of dementia, respectively. ApoE4 showed an independent effect on hippocampal atrophy in MCI and AD and in the pooled sample.

Figure 1

3D maps showing the regionally significant effects of ApoE4 genotype and parental history of AD on hippocampal radial distance (Areas in red and white show significant associations at p_corrected<0.05; areas in blue are nonsignificant, p_corrected>0.1).

Figure 2

3D comparison of hippocampal radial distance at baseline and in follow-up between MH+ and PH+ subjects in the pooled sample and in each diagnostic group (Areas in red and white show significant associations at p_corrected<0.05; areas in blue are nonsignificant, p_corrected>0.1; % difference =(radial distance at follow-up/radialdistance at baseline)*100).