title: Cortical Thickness and Microstructural White Matter Changes Detect Amnestic Mild Cognitive Impairment.
abstract: Both the apolipoprotein E (APOE) ɛ4 allele and amnestic mild cognitive impairment (aMCI) are considered to be risk factors for Alzheimer's disease (AD). The primary aim of this study was to determine whether the aMCI-related abnormality in gray matter (GM) cortical thickness and white matter (WM) tracts integrity would be modified by the APOE genotype. A total of 146 older adults, including 64 aMCI patients (28 ɛ4 carriers and 36 non-carriers) and 82 healthy controls (39 ɛ4 carriers and 43 non-carriers), underwent a standardized clinical interview, neuropsychological battery assessment, and multi-modal brain magnetic resonance imaging scans. Compared with control subjects, the patients with aMCI showed significantly reduced cortical thickness bilaterally in the parahippocampal gyrus and disrupted WM integrity in the limbic tracts (e.g., increased mean diffusivity in the right parahippocampal cingulum and bilateral uncinate fasciculus). However, no significant main effects of the APOE genotype and diagnosis-by-genotype interaction on GM thickness and WM integrity were observed. Further, diffusivity measures of the limbic WM tracts were significantly correlated with the parahippocampal atrophy in aMCI. Importantly, the parahippocampal thickness and diffusivity measures of the limbic WM tracts were significantly correlated with the cognitive performance (i.e., episodic memory Z score) in patients with aMCI. These results demonstrate that WM microstructural disruptions in the limbic tracts are present at the early stage of AD in an APOE-independent manner; and this degeneration may occur progressively, in parallel with parahippocampal atrophy, and may specifically contribute to early initial impairment in episodic memory.
authors.affiliation: Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
authors.forename: Zan
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Psychology, Sun Yat-sen University, Guangzhou, China.|State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.
authors.forename: Zhengjia
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Shu
authors.affiliation: Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
authors.forename: Duan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Qihao
authors.initials: Q
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001057:Apolipoproteins E / Q000235:genetics; D001284:Atrophy / Q000209:etiology / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000235:genetics; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005838:Genotype; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012372:ROC Curve; D018709:Statistics, Nonparametric; D066127:White Matter / Q000000981:diagnostic imaging / Q000503:physiopathology*
chemical_list: D001057:Apolipoproteins E
keywords: Alzheimer’s disease; amnestic mild cognitive impairment; apolipoprotein E; cortical thickness; white matter integrity