Age-related differences in the topological efficiency of the brain structural connectome in amnestic mild cognitive impairment

2017 ◽  
Vol 59 ◽  
pp. 144-155 ◽  
Author(s):  
Tengda Zhao ◽  
Can Sheng ◽  
Qiuhui Bi ◽  
Weili Niu ◽  
Ni Shu ◽  
...  
2020 ◽  
Vol 78 (1) ◽  
pp. 277-290
Author(s):  
Yan Li ◽  
Sha Li ◽  
Shunjiang Xu ◽  
Hong Yu ◽  
Longmei Tang ◽  
...  

Background: Age-related hormone changes play important roles in cognitive decline in older men, and apolipoprotein E ɛ4 (APOE ɛ4) is a risk factor for Alzheimer’s disease (AD). Objective: This study aimed to investigate the interactive role of androgen decline and APOE ɛ4 genotype in the pathogenesis of amnestic mild cognitive impairment (aMCI) and AD. Methods: In total, 576 elderly men over 65 years old from communities in Shijiazhuang were enrolled in this study, including 243 with normal cognition (NC), 271 with aMCI, and 62 with probable AD. Cognitive function was evaluated with a battery of neuropsychological tests. The serum levels of androgen and gonadotropin were detected by ELISA and chemiluminescence immunoassay. Results: The levels of free testosterone (FT) and dihydrotestosterone (DHT) were lower in the aMCI group (p < 0.05), and even lower in the AD group (p < 0.001), but the levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were higher in AD group (p < 0.01), comparing with that in NC or aMCI group. The interaction of lower FT or DHT levels with APOE ɛ4 had a risk role in global cognitive impairment (p < 0.05). The area under the curve (AUC) of the ROC curve for predicting aMCI by serum FT levels was 0.745. Conclusion: These results indicated that the interaction of androgen decline and APOE ɛ4 genotype play a role in aMCI and AD. Serum FT levels have a predictive value for aMCI and might be a potential biomarker for prodromal AD.


2005 ◽  
Vol 58 (5) ◽  
pp. 730-735 ◽  
Author(s):  
William R. Markesbery ◽  
Richard J. Kryscio ◽  
Mark A. Lovell ◽  
Jason D. Morrow

2018 ◽  
Vol 24 (8) ◽  
pp. 821-832 ◽  
Author(s):  
Nicole Carson ◽  
R. Shayna Rosenbaum ◽  
Morris Moscovitch ◽  
Kelly J. Murphy

AbstractObjectives: The self-reference effect (SRE), enhanced memory for self-related information, has been studied in healthy young and older adults but has had little investigation in people with age-related memory disorders, such as amnestic mild cognitive impairment (aMCI). Self-referential encoding may help to improve episodic memory in aMCI. Additionally, self-referential processing has been shown to benefit recollection, the vivid re-experiencing of past events, a phenomenon that has been termed the self-reference recollection effect (SRRE; Conway & Dewhurst, 1995). Furthermore, it remains unclear whether the valence of stimuli influences the appearance of the SRE and SRRE. Methods: The current study investigated the SRE and SRRE for trait adjective words in 20 individuals with aMCI and 30 healthy older adult controls. Ninety trait adjective words were allocated to self-reference, semantic, or structural encoding conditions; memory was later tested using a recognition test. Results: While healthy older adults showed a SRE, individuals with aMCI did not benefit from self-referential encoding over and above that of semantic encoding (an effect of “deep encoding”). A similar pattern was apparent for the SRRE; healthy controls showed enhanced recollection for words encoded in the self-reference condition, while the aMCI group did not show specific benefit to recollection for self-referenced over semantically encoded items. No effects of valence were found. Conclusions: These results indicate that while memory for trait adjective words can be improved in aMCI with deep encoding strategies (whether self-reference or semantic), self-referencing does not provide an additional benefit. (JINS, 2018, 24, 821–832)


2020 ◽  
Vol 30 (8) ◽  
pp. 4651-4661 ◽  
Author(s):  
Xin Li ◽  
Yezhou Wang ◽  
Wenxiao Wang ◽  
Weijie Huang ◽  
Kewei Chen ◽  
...  

Abstract Brain disconnection model has been proposed as a possible neural mechanism for cognitive aging. However, the relationship between structural connectivity degeneration and cognitive decline with normal aging remains unclear. In the present study, using diffusion MRI and tractography techniques, we report graph theory-based analyses of the brain structural connectome in a cross-sectional, community-based cohort of 633 cognitively healthy elderly individuals. Comprehensive neuropsychological assessment of the elderly subjects was performed. The association between age, brain structural connectome, and cognition across elderly individuals was examined. We found that the topological efficiency, modularity, and hub integration of the brain structural connectome exhibited a significant decline with normal aging, especially in the frontal, parietal, and superior temporal regions. Importantly, network efficiency was positively correlated with attention and executive function in elderly subjects and had a significant mediation effect on the age-related decline in these cognitive functions. Moreover, nodal efficiency of the brain structural connectome showed good performance for the prediction of attention and executive function in elderly individuals. Together, our findings revealed topological alterations of the brain structural connectome with normal aging, which provides possible structural substrates underlying cognitive aging and sensitive imaging markers for the individual prediction of cognitive functions in elderly subjects.


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