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  • 1
    In: Neurology, Ovid Technologies (Wolters Kluwer Health), Vol. 96, No. 24 ( 2021-06-15), p. e2920-e2932
    Abstract: To determine whether following a Mediterranean-like diet (MeDi) relates to cognitive functions and in vivo biomarkers for Alzheimer disease (AD), we analyzed cross-sectional data from the German DZNE-Longitudinal Cognitive Impairment and Dementia Study. Method The sample (n = 512, mean age 69.5 ± 5.9 years) included 169 cognitively normal participants and individuals at higher AD risk (53 with relatives with AD, 209 with subjective cognitive decline, and 81 with mild cognitive impairment). We defined MeDi adherence according to the food frequency questionnaire. Brain volume outcomes were generated via voxel-based morphometry on T1-MRI, and cognitive performance was assessed with an extensive neuropsychological battery. AD-related biomarkers (β-amyloid 42/40 [Aβ 42/40 ] ratio, phosphorylated tau 181 [pTau181] ) in CSF were assessed in n = 226 individuals. We analyzed the associations between MeDi and outcomes with linear regression models controlling for several covariates. In addition, we applied hypothesis-driven mediation and moderation analysis. Results Higher MeDi adherence related to larger mediotemporal gray matter volume ( p 〈 0.05 family-wise error corrected), better memory (β ± SE = 0.03 ± 0.02; p = 0.038), and less amyloid (Aβ 42/40 ratio, β ± SE = 0.003 ± 0.001; p = 0.008) and pTau181 (β ± SE = −1.96 ± 0.68; p = 0.004) pathology. Mediotemporal volume mediated the association between MeDi and memory (40% indirect mediation). Finally, MeDi favorably moderated the associations among Aβ 42/40 ratio, pTau181, and mediotemporal atrophy. Results were consistent correcting for APOE -ε4 status. Conclusion Our findings corroborate the view of MeDi as a protective factor against memory decline and mediotemporal atrophy. They suggest that these associations might be explained by a decrease of amyloidosis and tau pathology. Longitudinal and dietary intervention studies should further examine this conjecture and its treatment implications.
    Type of Medium: Online Resource
    ISSN: 0028-3878 , 1526-632X
    RVK:
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
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  • 2
    In: Alzheimer's Research & Therapy, Springer Science and Business Media LLC, Vol. 15, No. 1 ( 2023-05-24)
    Abstract: White matter hyperintensities (WMH) in subjects across the Alzheimer’s disease (AD) spectrum with minimal vascular pathology suggests that amyloid pathology—not just arterial hypertension—impacts WMH, which in turn adversely influences cognition. Here we seek to determine the effect of both hypertension and Aβ positivity on WMH, and their impact on cognition. Methods We analysed data from subjects with a low vascular profile and normal cognition (NC), subjective cognitive decline (SCD), and amnestic mild cognitive impairment (MCI) enrolled in the ongoing observational multicentre DZNE Longitudinal Cognitive Impairment and Dementia Study ( n  = 375, median age 70.0 [IQR 66.0, 74.4] years; 178 female; NC/SCD/MCI 127/162/86). All subjects underwent a rich neuropsychological assessment. We focused on baseline memory and executive function—derived from multiple neuropsychological tests using confirmatory factor analysis—, baseline preclinical Alzheimer’s cognitive composite 5 (PACC5) scores, and changes in PACC5 scores over the course of three years (ΔPACC5). Results Subjects with hypertension or Aβ positivity presented the largest WMH volumes ( p FDR   〈  0.05), with spatial overlap in the frontal (hypertension: 0.42 ± 0.17; Aβ: 0.46 ± 0.18), occipital (hypertension: 0.50 ± 0.16; Aβ: 0.50 ± 0.16), parietal lobes (hypertension: 0.57 ± 0.18; Aβ: 0.56 ± 0.20), corona radiata (hypertension: 0.45 ± 0.17; Aβ: 0.40 ± 0.13), optic radiation (hypertension: 0.39 ± 0.18; Aβ: 0.74 ± 0.19), and splenium of the corpus callosum (hypertension: 0.36 ± 0.12; Aβ: 0.28 ± 0.12). Elevated global and regional WMH volumes coincided with worse cognitive performance at baseline and over 3 years ( p FDR   〈  0.05). Aβ positivity was negatively associated with cognitive performance ( direct effect —memory: − 0.33 ± 0.08, p FDR   〈  0.001; executive: − 0.21 ± 0.08, p FDR   〈  0.001; PACC5: − 0.29 ± 0.09, p FDR  = 0.006; ΔPACC5: − 0.34 ± 0.04, p FDR   〈  0.05). Splenial WMH mediated the relationship between hypertension and cognitive performance ( indirect-only effect —memory: − 0.05 ± 0.02, p FDR  = 0.029; executive: − 0.04 ± 0.02, p FDR  = 0.067; PACC5: − 0.05 ± 0.02, p FDR  = 0.030; ΔPACC5: − 0.09 ± 0.03, p FDR  = 0.043) and WMH in the optic radiation partially mediated that between Aβ positivity and memory ( indirect effect —memory: − 0.05 ± 0.02, p FDR  = 0.029). Conclusions Posterior white matter is susceptible to hypertension and Aβ accumulation. Posterior WMH mediate the association between these pathologies and cognitive dysfunction, making them a promising target to tackle the downstream damage related to the potentially interacting and potentiating effects of the two pathologies. Trial registration German Clinical Trials Register (DRKS00007966, 04/05/2015).
    Type of Medium: Online Resource
    ISSN: 1758-9193
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2506521-X
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  • 3
    In: Alzheimer's Research & Therapy, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2018-12)
    Type of Medium: Online Resource
    ISSN: 1758-9193
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2018
    detail.hit.zdb_id: 2506521-X
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  • 4
    In: Cerebral Cortex, Oxford University Press (OUP), Vol. 31, No. 11 ( 2021-10-01), p. 4901-4915
    Abstract: Several Alzheimer’s disease (AD) atrophy subtypes were identified, but their brain network properties are unclear. We analyzed data from two independent datasets, including 166 participants (103 AD/63 controls) from the DZNE-longitudinal cognitive impairment and dementia study and 151 participants (121 AD/30 controls) from the AD neuroimaging initiative cohorts, aiming to identify differences between AD atrophy subtypes in resting-state functional magnetic resonance imaging intra-network connectivity (INC) and global and nodal network properties. Using a data-driven clustering approach, we identified four AD atrophy subtypes with differences in functional connectivity, accompanied by clinical and biomarker alterations, including a medio-temporal-predominant (S-MT), a limbic-predominant (S-L), a diffuse (S-D), and a mild-atrophy (S-MA) subtype. S-MT and S-D showed INC reduction in the default mode, dorsal attention, visual and limbic network, and a pronounced reduction of “global efficiency” and decrease of the “clustering coefficient” in parietal and temporal lobes. Despite severe atrophy in limbic areas, the S-L exhibited only marginal global network but substantial nodal network failure. S-MA, in contrast, showed limited impairment in clinical and cognitive scores but pronounced global network failure. Our results contribute toward a better understanding of heterogeneity in AD with the detection of distinct differences in functional connectivity networks accompanied by CSF biomarker and cognitive differences in AD subtypes.
    Type of Medium: Online Resource
    ISSN: 1047-3211 , 1460-2199
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1483485-6
    SSG: 12
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  • 5
    In: Brain, Oxford University Press (OUP), Vol. 145, No. 4 ( 2022-05-24), p. 1473-1485
    Abstract: We investigated whether the impact of tau-pathology on memory performance and on hippocampal/medial temporal memory function in non-demented individuals depends on the presence of amyloid pathology, irrespective of diagnostic clinical stage. We conducted a cross-sectional analysis of the observational, multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE). Two hundred and thirty-five participants completed task functional MRI and provided CSF (92 cognitively unimpaired, 100 experiencing subjective cognitive decline and 43 with mild cognitive impairment). Presence (A+) and absence (A−) of amyloid pathology was defined by CSF amyloid-β42 (Aβ42) levels. Free recall performance in the Free and Cued Selective Reminding Test, scene recognition memory accuracy and hippocampal/medial temporal functional MRI novelty responses to scene images were related to CSF total-tau and phospho-tau levels separately for A+ and A− individuals. We found that total-tau and phospho-tau levels were negatively associated with memory performance in both tasks and with novelty responses in the hippocampus and amygdala, in interaction with Aβ42 levels. Subgroup analyses showed that these relationships were only present in A+ and remained stable when very high levels of tau ( & gt;700 pg/ml) and phospho-tau ( & gt;100 pg/ml) were excluded. These relationships were significant with diagnosis, age, education, sex, assessment site and Aβ42 levels as covariates. They also remained significant after propensity score based matching of phospho-tau levels across A+ and A− groups. After classifying this matched sample for phospho-tau pathology (T−/T+), individuals with A+/T+ were significantly more memory-impaired than A−/T+ despite the fact that both groups had the same amount of phospho-tau pathology. ApoE status (presence of the E4 allele), a known genetic risk factor for Alzheimer’s disease, did not mediate the relationship between tau pathology and hippocampal function and memory performance. Thus, our data show that the presence of amyloid pathology is associated with a linear relationship between tau pathology, hippocampal dysfunction and memory impairment, although the actual severity of amyloid pathology is uncorrelated. Our data therefore indicate that the presence of amyloid pathology provides a permissive state for tau-related hippocampal dysfunction and hippocampus-dependent recognition and recall impairment. This raises the possibility that in the predementia stage of Alzheimer’s disease, removing the negative impact of amyloid pathology could improve memory and hippocampal function even if the amount of tau-pathology in CSF is not changed, whereas reducing increased CSF tau-pathology in amyloid-negative individuals may not proportionally improve memory function.
    Type of Medium: Online Resource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 1474117-9
    SSG: 12
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  • 6
    In: Neurobiology of Aging, Elsevier BV, Vol. 124 ( 2023-04), p. 18-28
    Type of Medium: Online Resource
    ISSN: 0197-4580
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2023
    detail.hit.zdb_id: 1498414-3
    SSG: 12
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  • 7
    In: Alzheimer's & Dementia, Wiley
    Abstract: It remains unclear whether functional brain networks are consistently altered in individuals with subjective cognitive decline (SCD) of diverse ethnic and cultural backgrounds and whether the network alterations are associated with an amyloid burden. METHODS Cross‐sectional resting‐state functional magnetic resonance imaging connectivity (FC) and amyloid‐positron emission tomography (PET) data from the Chinese Sino Longitudinal Study on Cognitive Decline and German DZNE Longitudinal Cognitive Impairment and Dementia cohorts were analyzed. RESULTS Limbic FC, particularly hippocampal connectivity with right insula, was consistently higher in SCD than in controls, and correlated with SCD‐plus features. Smaller SCD subcohorts with PET showed inconsistent amyloid positivity rates and FC–amyloid associations across cohorts. DISCUSSION Our results suggest an early adaptation of the limbic network in SCD, which may reflect increased awareness of cognitive decline, irrespective of amyloid pathology. Different amyloid positivity rates may indicate a heterogeneous underlying etiology in Eastern and Western SCD cohorts when applying current research criteria. Future studies should identify culture‐specific features to enrich preclinical Alzheimer's disease in non‐Western populations. Highlights Common limbic hyperconnectivity across Chinese and German subjective cognitive decline (SCD) cohorts was observed. Limbic hyperconnectivity may reflect awareness of cognition, irrespective of amyloid load. Further cross‐cultural harmonization of SCD regarding Alzheimer's disease pathology is required.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2201940-6
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  • 8
    In: Alzheimer's Research & Therapy, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2020-12)
    Abstract: Early identification of individuals at risk of dementia is mandatory to implement prevention strategies and design clinical trials that target early disease stages. Subjective cognitive decline (SCD) and neuropsychiatric symptoms (NPS) have been proposed as potential markers for early manifestation of Alzheimer’s disease (AD). We aimed to investigate the frequency of NPS in SCD, in other at-risk groups, in healthy controls (CO), and in AD patients, and to test the association of NPS with AD biomarkers, with a particular focus on cognitively unimpaired participants with or without SCD-related worries. Methods We analyzed data of n  = 687 participants from the German DZNE Longitudinal Cognitive Impairment and Dementia (DELCODE) study, including the diagnostic groups SCD ( n  = 242), mild cognitive impairment (MCI, n  = 115), AD ( n  = 77), CO ( n  = 209), and first-degree relatives of AD patients (REL, n  = 44). The Neuropsychiatric Inventory Questionnaire (NPI-Q), Geriatric Depression Scale (GDS-15), and Geriatric Anxiety Inventory (GAI-SF) were used to assess NPS. We examined differences of NPS frequency between diagnostic groups. Logistic regression analyses were carried out to further investigate the relationship between NPS and cerebrospinal fluid (CSF) AD biomarkers, focusing on a subsample of cognitively unimpaired participants (SCD, REL, and CO), who were further differentiated based on reported worries. Results The numbers of reported NPS, depression scores, and anxiety scores were significantly higher in subjects with SCD compared to CO. The quantity of reported NPS in subjects with SCD was lower compared to the MCI and AD group. In cognitively unimpaired subjects with worries, low Aß42 was associated with higher rates of reporting two or more NPS (OR 0.998, 95% CI 0.996–1.000, p   〈  .05). Conclusion These findings give insight into the prevalence of NPS in different diagnostic groups, including SCD and healthy controls. NPS based on informant report seem to be associated with underlying AD pathology in cognitively unimpaired participants who worry about cognitive decline. Trial registration German Clinical Trials Register DRKS00007966 . Registered 4 May 2015.
    Type of Medium: Online Resource
    ISSN: 1758-9193
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
    detail.hit.zdb_id: 2506521-X
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  • 9
    In: Journal of Alzheimer's Disease, IOS Press, Vol. 95, No. 3 ( 2023-09-26), p. 1013-1028
    Abstract: Background: Atrophy of cholinergic basal forebrain (BF) nuclei is a frequent finding in magnetic resonance imaging (MRI) volumetry studies that examined patients with prodromal or clinical Alzheimer’s disease (AD), but less clear for individuals in earlier stages of the clinical AD continuum. Objective: To examine BF volume reductions in subjective cognitive decline (SCD) participants with AD pathologic changes. Methods: The present study compared MRI-based BF volume measurements in age- and sex-matched samples of N = 24 amyloid-positive and N = 24 amyloid-negative SCD individuals, based on binary visual ratings of Florbetaben positron emission tomography (PET) measurements. Additionally, we assessed associations of BF volume with cortical amyloid burden, based on semiquantitative Centiloid (CL) analyses. Results: Group differences approached significance for BF total volume (p = 0.061) and the Ch4 subregion (p = 0.059) only, showing the expected relative volume reductions for the amyloid-positive subgroup. There were also significant inverse correlations between BF volumes and CL values, which again were most robust for BF total volume and the Ch4 subregion. Conclusions: The results are consistent with the hypothesis that amyloid-positive SCD individuals, which are considered to represent a transitional stage on the clinical AD continuum, already show incipient alterations of BF integrity. The negative association with a continuous measure of cortical amyloid burden also suggests that this may reflect an incremental process. Yet, further research is needed to evaluate whether BF changes already emerge at “grey zone” levels of amyloid accumulation, before amyloidosis is reliably detected by PET visual readings.
    Type of Medium: Online Resource
    ISSN: 1387-2877 , 1875-8908
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2023
    detail.hit.zdb_id: 2070772-1
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  • 10
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S6 ( 2022-12)
    Abstract: The new consensus definition of cognitive reserve (CR) provides a framework to study individual differences in cognitive functioning relative to aging and disease. CR denotes a property of the brain that allows for better than expected cognitive performance given the degree of age‐related brain changes or disease. More specifically, individual differences in patterns of brain activity during fMRI tasks might explain the differential susceptibility to pathological burden. Method According to the consensus definitions, we sought to identify and quantify CR from fMRI novelty‐contrast maps in a large multi‐centric sample (DELCODE) consisting of 215 participants with SCD, 79 with MCI, 30 with AD dementia, 56 AD relatives and 156 cognitively normal controls (CN). CSF amyloid‐42/40 ratio, CSF p‐tau and hippocampal volume (ATN) were reduced to a single number, representing a (Alzheimer’s) disease progression (DP) score. To identify a CR network, voxel‐wise linear regression models determined where functional task‐activation moderates the relationship between DP and cognition. Finally, task‐related activity within the CR network was extracted to obtain individual fMRI‐based CR scores. Result The DP score showed a strong negative quadratic association with baseline memory scores. CR voxels, in which higher or lower activation were associated with better cognition, weakening the effect of DP, were mainly located within the novelty network. They included lateral‐occipital and superior‐parietal regions, lingual and fusiform gyrus, cuneus and small parts of cingulate. While there was no association between the CR score and cognition in CNs, higher CR scores in MCI and AD patients were related to higher PACC5 scores. Conclusion We established a DP score that collapses the ATN measures into a single number, while retaining its deleterious effect on an individual’s memory score. Furthermore, a newly identified task‐dependent CR network could be used to establish a CR score, which was related to higher PACC5 scores in MCI and AD patients, suggesting a functional compensation mechanism at later stages of AD that is not yet present in CN. Thus, targeted alteration of brain activity might be a promising route to modify cognitive trajectories in MCI and AD patients. Further, detailed examination of individuals with high CR might reveal additional disease‐modifying factors.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
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