•Composite scores provide reliable metrics of domain function in multicenter cohort.•Visuo-spatial domain composite scores relate to anatomic changes in AD spectrum.•Domain scores relate to ...network-specific resting-state connectivity in AD spectrum.
Cognitive decline has been found to be associated with gray matter atrophy and disruption of functional neural networks in Alzheimer’s disease (AD) in structural and functional imaging (fMRI) studies. Most previous studies have used single test scores of cognitive performance among monocentric cohorts. However, cognitive domain composite scores could be more reliable than single test scores due to the reduction of measurement error. Adopting a multicentric resting state fMRI (rs-fMRI) and cognitive domain approach, we provide a comprehensive description of the structural and functional correlates of the key cognitive domains of AD.
We analyzed MRI, rs-fMRI and cognitive domain score data of 490 participants from an interim baseline release of the multicenter DELCODE study cohort, including 54 people with AD, 86 with Mild Cognitive Impairment (MCI), 175 with Subjective Cognitive Decline (SCD), and 175 Healthy Controls (HC) in the AD-spectrum. Resulting cognitive domain composite scores (executive, visuo-spatial, memory, working memory and language) from the DELCODE neuropsychological battery (DELCODE-NP), were previously derived using confirmatory factor analysis. Statistical analyses examined the differences between diagnostic groups, and the association of composite scores with regional atrophy and network-specific functional connectivity among the patient subgroup of SCD, MCI and AD.
Cognitive performance, atrophy patterns and functional connectivity significantly differed between diagnostic groups in the AD-spectrum. Regional gray matter atrophy was positively associated with visuospatial and other cognitive impairments among the patient subgroup in the AD-spectrum. Except for the visual network, patterns of network-specific resting-state functional connectivity were positively associated with distinct cognitive impairments among the patient subgroup in the AD-spectrum.
Consistent associations between cognitive domain scores and both regional atrophy and network-specific functional connectivity (except for the visual network), support the utility of a multicentric and cognitive domain approach towards explicating the relationship between imaging markers and cognition in the AD-spectrum.
•Multimodal MRI analysis of cholinergic basal forebrain (cBF) changes in AD spectrum.•Robust changes in cBF volume and diffusivity in MCI and AD dementia.•Only minimal changes in cBF functional ...connectivity across the AD spectrum.•No imaging modality detects significant cBF changes in subjective cognitive decline.•Similar results in subset analysis of patients with biomarker-confirmed Aβ-pathology.
Dysfunction of the cholinergic basal forebrain (cBF) is associated with cognitive decline in Alzheimer’s disease (AD). Multimodal MRI allows for the investigation of cBF changes in-vivo. In this study we assessed alterations in cBF functional connectivity (FC), mean diffusivity (MD), and volume across the spectrum of AD. We further assessed effects of amyloid pathology on these changes.
Participants included healthy controls, and subjects with subjective cognitive decline (SCD), mild cognitive impairment (MCI), or AD dementia (ADD) from the multicenter DELCODE study. Resting-state functional MRI (rs-fMRI) and structural MRI data was available for 477 subjects, and a subset of 243 subjects also had DTI data available. Differences between diagnostic groups were investigated using seed-based FC, volumetric, and MD analyses of functionally defined anterior (a-cBF) and posterior (p-cBF) subdivisions of a cytoarchitectonic cBF region-of-interest. In complementary analyses groups were stratified according to amyloid status based on CSF Aβ42/40 biomarker data, which was available in a subset of participants.
a-cBF and p-cBF subdivisions showed regional FC profiles that were highly consistent with previously reported patterns, but there were only minimal differences between diagnostic groups. Compared to controls, cBF volumes and MD were significantly different in MCI and ADD but not in SCD. The Aβ42/40 stratified analyses largely matched these results.
We reproduced subregion-specific FC profiles of the cBF in a clinical sample spanning the AD spectrum. At least in this multicentric cohort study, cBF-FC did not show marked changes along the AD spectrum, and multimodal MRI did not provide more sensitive measures of AD-related cBF changes compared to volumetry.
Alzheimer's disease (AD) is most the frequent neurodegenerative disease, and the APOE ε4 allele is the most prominent risk factor for late-onset AD. Here, we present an iPSC line generated from ...peripheral blood cells of a male AD patient employing Sendai virus vectors encoding the transcription factors OCT4, SOX2, KLF4 and c-MYC. The characterized iPSC line expresses typical human pluripotency markers and shows differentiation into all three germ layers, complete reprogramming vector clearance, a normal SNP genotype and maintenance of the APOE ε4/ε4 allele.
INTRODUCTION
Soluble amyloid beta (Aβ) oligomers have been suggested as initiating Aβ related neuropathologic change in Alzheimer's disease (AD) but their quantitative distribution and chronological ...sequence within the AD continuum remain unclear.
METHODS
A total of 526 participants in early clinical stages of AD and controls from a longitudinal cohort were neurobiologically classified for amyloid and tau pathology applying the AT(N) system. Aβ and tau oligomers in the quantified cerebrospinal fluid (CSF) were measured using surface‐based fluorescence intensity distribution analysis (sFIDA) technology.
RESULTS
Across groups, highest Aβ oligomer levels were found in A+ with subjective cognitive decline and mild cognitive impairment. Aβ oligomers were significantly higher in A+T− compared to A−T− and A+T+. APOE ε4 allele carriers showed significantly higher Aβ oligomer levels. No differences in tau oligomers were detected.
DISCUSSION
The accumulation of Aβ oligomers in the CSF peaks early within the AD continuum, preceding tau pathology. Disease‐modifying treatments targeting Aβ oligomers might have the highest therapeutic effect in these disease stages.
Highlights
Using surface‐based fluorescence intensity distribution analysis (sFIDA) technology, we quantified Aβ oligomers in cerebrospinal fluid (CSF) samples of the DZNE‐Longitudinal Cognitive Impairment and Dementia (DELCODE) cohort
Aβ oligomers were significantly elevated in mild cognitive impairment (MCI)
Amyloid‐positive subjects in the subjective cognitive decline (SCD) group increased compared to the amyloid‐negative control group
Interestingly, levels of Aβ oligomers decrease at advanced stages of the disease (A+T+), which might be explained by altered clearing mechanisms
INTRODUCTION
We investigated the association of inflammatory mechanisms with markers of Alzheimer's disease (AD) pathology and rates of cognitive decline in the AD spectrum.
METHODS
We studied 296 ...cases from the Deutsches Zentrum für Neurodegenerative Erkrankungen Longitudinal Cognitive Impairment and Dementia Study (DELCODE) cohort, and an extension cohort of 276 cases of the Alzheimer's Disease Neuroimaging Initiative study. Using Bayesian confirmatory factor analysis, we constructed latent factors for synaptic integrity, microglia, cerebrovascular endothelial function, cytokine/chemokine, and complement components of the inflammatory response using a set of inflammatory markers in cerebrospinal fluid.
RESULTS
We found strong evidence for an association of synaptic integrity, microglia response, and cerebrovascular endothelial function with a latent factor of AD pathology and with rates of cognitive decline. We found evidence against an association of complement and cytokine/chemokine factors with AD pathology and rates of cognitive decline.
DISCUSSION
Latent factors provided access to directly unobservable components of the neuroinflammatory response and their association with AD pathology and cognitive decline.
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In daily life, responses are often facilitated by anticipatory imagery of expected targets which are announced by associated stimuli from different sensory modalities. Silent music ...reading represents an intriguing case of visuotonal modality transfer in working memory as it induces highly defined auditory imagery on the basis of presented visuospatial information (i.e. musical notes). Using functional MRI and a delayed sequence matching-to-sample paradigm, we compared brain activations during retention intervals (10s) of visual (VV) or tonal (TT) unimodal maintenance versus visuospatial-to-tonal modality transfer (VT) tasks. Visual or tonal sequences were comprised of six elements, white squares or tones, which were low, middle, or high regarding vertical screen position or pitch, respectively (presentation duration: 1.5s). For the cross-modal condition (VT, session 3), the visuospatial elements from condition VV (session 1) were re-defined as low, middle or high “notes” indicating low, middle or high tones from condition TT (session 2), respectively, and subjects had to match tonal sequences (probe) to previously presented note sequences. Tasks alternately had low or high cognitive load. To evaluate possible effects of music reading expertise, 15 singers and 15 non-musicians were included. Scanner task performance was excellent in both groups. Despite identity of applied visuospatial stimuli, visuotonal modality transfer versus visual maintenance (VT>VV) induced “inhibition” of visual brain areas and activation of primary and higher auditory brain areas which exceeded auditory activation elicited by tonal stimulation (VT>TT). This transfer-related visual-to-auditory activation shift occurred in both groups but was more pronounced in experts. Frontoparietal areas were activated by higher cognitive load but not by modality transfer. The auditory brain showed a potential to anticipate expected auditory target stimuli on the basis of non-auditory information and sensory brain activation rather mirrored expectation than stimulation. Silent music reading probably relies on these basic neurocognitive mechanisms.
Impaired long-term memory is a defining feature of mild cognitive impairment (MCI). We tested whether this impairment is item specific, limited to some memoranda, whereas some remain consistently ...memorable.
We conducted item-based analyses of long-term visual recognition memory. Three hundred ninety-four participants (healthy controls, subjective cognitive decline SCD, and MCI) in the multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE) were tested with images from a pool of 835 photographs.
We observed consistent memorability for images in healthy controls, SCD, and MCI, predictable by a neural network trained on another healthy sample. Looking at memorability differences between groups, we identified images that could successfully categorize group membership with higher success and a substantial image reduction than the original image set.
Individuals with SCD and MCI show consistent memorability for specific items, while other items show significant diagnosticity. Certain stimulus features could optimize diagnostic assessment, while others could support memory.
Errorless learning (EL) is a method for optimizing learning, which uses feed-forward instructions in order to prevent people from making mistakes during the learning process. The majority of previous ...studies on EL taught patients with dementia artificial tasks of little or no relevance for their daily lives. Furthermore, only a few controlled studies on EL have so far been performed and just a handful of studies have examined the long-term effects of EL. Tasks were not always trained in the patients' natural or home environment, limiting the external validity of these studies. This multicenter parallel randomized controlled trial examines the effects of EL compared with trial and error learning (TEL) on the performance of activities of daily living in persons with Alzheimer's or mixed-type dementia living at home.
Patients received nine 1-hour task training sessions over eight weeks using EL or TEL. Task performance was measured using video observations at week 16. Secondary outcome measures were task performance measured at week 26, satisfaction with treatment, need for assistance, challenging behavior, adverse events, resource utilization and treatment costs.
A total of 161 participants were randomized, of whom 71 completed the EL and 74 the TEL arm at week 11. Sixty-nine EL patients and 71 TEL patients were assessed at the 16-week follow-up (the primary measurement endpoint). Intention-to-treat analysis showed a significantly improved task performance in both groups. No significant differences between the treatment groups were found for primary or secondary outcomes.
Structured relearning improved the performance of activities of daily living. Improvements were maintained for 6 months. EL had no additional effect over TEL.
German Register of Clinical Trials DRKS00003117 . Registered 31 May 2011.
Introduction
The behavioral variant of frontotemporal dementia (bvFTD) is a rare neurodegenerative disease. Reliable predictors of disease progression have not been sufficiently identified. We ...investigated multivariate magnetic resonance imaging (MRI) biomarker profiles for their predictive value of individual decline.
Methods
One hundred five bvFTD patients were recruited from the German frontotemporal lobar degeneration (FTLD) consortium study. After defining two groups (“fast progressors” vs. “slow progressors”), we investigated the predictive value of MR brain volumes for disease progression rates performing exhaustive screenings with multivariate classification models.
Results
We identified areas that predict disease progression rate within 1 year. Prediction measures revealed an overall accuracy of 80% across our 50 top classification models. Especially the pallidum, middle temporal gyrus, inferior frontal gyrus, cingulate gyrus, middle orbitofrontal gyrus, and insula occurred in these models.
Discussion
Based on the revealed marker combinations an individual prognosis seems to be feasible. This might be used in clinical studies on an individualized progression model.
With upcoming therapeutic interventions for patients with primary progressive aphasia (PPA), instruments for the follow-up of patients are needed to describe disease progression and to evaluate ...potential therapeutic effects. So far, volumetric brain changes have been proposed as clinical endpoints in the literature, but cognitive scores are still lacking. This study followed disease progression predominantly in language-based performance within 1 year and defined a PPA sum score which can be used in therapeutic interventions.
We assessed 28 patients with nonfluent variant PPA, 17 with semantic variant PPA, 13 with logopenic variant PPA, and 28 healthy controls in detail for 1 year. The most informative neuropsychological assessments were combined to a sum score, and associations between brain atrophy were investigated followed by a sample size calculation for clinical trials.
Significant absolute changes up to 20% in cognitive tests were found after 1 year. Semantic and phonemic word fluency, Boston Naming Test, Digit Span, Token Test, AAT Written language, and Cookie Test were identified as the best markers for disease progression. These tasks provide the basis of a new PPA sum score. Assuming a therapeutic effect of 50% reduction in cognitive decline for sample size calculations, a number of 56 cases is needed to find a significant treatment effect. Correlations between cognitive decline and atrophy showed a correlation up to r = 0.7 between the sum score and frontal structures, namely the superior and inferior frontal gyrus, as well as with left-sided subcortical structures.
Our findings support the high performance of the proposed sum score in the follow-up of PPA and recommend it as an outcome measure in intervention studies.
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