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- Shahid, Syed Salman, et al.
(författare)
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Hippocampal-subfield microstructures and their relation to plasma biomarkers in Alzheimer's disease.
- 2022
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 145:6, s. 2149-2160
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Tidskriftsartikel (refereegranskat)abstract
- Hippocampal subfields exhibit differential vulnerabilities to Alzheimer's disease (AD)-associated pathology including abnormal accumulation of beta-amyloid deposition and neurofibrillary tangles. These pathological processes extensively impact on the structural and functional interconnectivities of the subfields and may explain the association between hippocampal dysfunction and cognitive deficits. In the present study, we investigated the degree of alterations in the microstructure of hippocampal subfields across the clinical continuum of AD. We applied a gray matter (GM) specific multi-compartment diffusion model (Cortical-NODDI) to understand the differential effects of AD pathology on the hippocampal subfield microstructure. A total of 119 participants were included in this cross-sectional study. Participants were stratified into three categories, cognitively normal (CN; N=47), mild cognitive impairment (MCI; N=52), and AD (N=19). Diffusion MRI, plasma biomarkers, and neuropsychological test scores were used to determine the association between the microstructural integrity and AD associated molecular indicators and cognition. For AD-related plasma biomarkers, we studied amyloid beta (Aβ), total tau (T-tau), and neurofilament light (NfL); for AD-related neuropsychological tests, we included the Trail Making Test (TMT), Rey Auditory Verbal Learning Test (RAVLT), Digit Span, and Montreal Cognitive Assessment (MoCA). Comparisons between CN and MCI showed significant microstructural alterations in the hippocampal cornu ammonis (CA) 4 and dentate gyrus (DG) region, whereas CA1-3 was the most sensitive region for the later stages in the AD clinical continuum. Among imaging metrics for microstructures, the volume fraction of isotropic diffusion for interstitial free water demonstrated the largest effect size in between-group comparisons. Regarding the plasma biomarkers, NfL appeared to be the most sensitive biomarker for associations with microstructural imaging findings in CA4-DG. CA1-3 was the subfield which had stronger correlations between cognitive performance and microstructural metrics. Particularly, poor performance in RAVLT and MoCA was associated with decreased intracellular volume fraction. Overall, our findings support the value of tissue-specific microstructural imaging for providing pathologically relevant information manifesting in the plasma biomarkers and neuropsychological outcomes across various stages of AD.
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| 2. |
- Wang, Hui-Xin, et al.
(författare)
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Late Life Leisure Activities and Risk of Cognitive Decline
- 2013
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Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - : Oxford University Press (OUP). - 1079-5006 .- 1758-535X. ; 68:2, s. 205-213
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Tidskriftsartikel (refereegranskat)abstract
- Background. Studies concerning the effect of different types of leisure activities on various cognitive domains are limited. This study tests the hypothesis that mental, physical, and social activities have a domain-specific protection against cognitive decline. Methods. A cohort of a geographically defined population in China was examined in 2003-2005 and followed for an average of 2.4 years. Leisure activities were assessed in 1,463 adults aged 65 years and older without cognitive or physical impairment at baseline, and their cognitive performances were tested at baseline and follow-up examinations. Results. High level of mental activity was related to less decline in global cognition (beta = -.23, p < .01), language (beta = -.11, p < .05), and executive function (beta = -.13, p < .05) in ANCOVA models adjusting for age, gender, education, history of stroke, body mass index, Apolipoprotein E genotype, and baseline cognition. High level of physical activity was related to less decline in episodic memory (beta = -.08, p < .05) and language (beta = -.15, p < .01). High level of social activity was associated with less decline in global cognition (beta = -.11, p < .05). Further, a dose-response pattern was observed: although participants who did not engage in any of the three activities experienced a significant global cognitive decline, those who engaged in any one of the activities maintained their cognition, and those who engaged in two or three activities improved their cognition. The same pattern was observed in men and in women. Conclusions. Leisure activities in old age may protect against cognitive decline for both women and men, and different types of activities seem to benefit different cognitive domains.
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