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The Dominantly Inherited Alzheimer Network (DIAN) Observational Study is an international collaboration studying autosomal dominant Alzheimer disease (ADAD). This rare form of Alzheimer disease (AD) is caused by mutations in the presenilin 1 (PSEN1), presenilin 2 (PSEN2), or amyloid precursor protein (APP) genes. As individuals from these families have a 50% chance of inheriting the familial mutation, this provides researchers with a well-matched cohort of carriers vs non-carriers for case-control studies. An important trait of ADAD is that the age at symptom onset is highly predictable and consistent for each specific mutation, allowing researchers to estimate an individual’s point in their disease time course prior to symptom onset. Although ADAD represents only a small proportion (approximately 0.1%) of all AD cases, studying this form of AD allows researchers to investigate preclinical AD and the progression of changes that occur within the brain prior to AD symptom onset. Furthermore, the young age at symptom onset (typically 30-60 years) means age-related comorbidities are much less prevalent than in sporadic AD, thereby allowing AD pathophysiology to be studied independent of these confounds. A major goal of the DIAN Observational Study is to create a global resource for AD researchers. To that end, the current manuscript provides an overview of the DIAN magnetic resonance imaging (MRI) and positron emission tomography (PET) protocols and highlights the key imaging results of this study to date.

Important insights into the early pathogenesis of Alzheimer's disease can be provided by studies of autosomal dominant Alzheimer's disease and Down syndrome. However, it is unclear whether the timing and spatial distribution of amyloid accumulation differs between people with autosomal dominant Alzheimer's disease and those with Down syndrome. We aimed to directly compare amyloid changes between these two groups of people.In this cross-sectional study, we included participants (aged ≥25 years) with Down syndrome and sibling controls who had MRI and amyloid PET scans in the first data release (January, 2020) of the Alzheimer's Biomarker Consortium-Down Syndrome (ABC-DS) study. We also included carriers of autosomal dominant Alzheimer's disease genetic mutations and non-carrier familial controls who were within a similar age range to ABC-DS participants (25-73 years) and had MRI and amyloid PET scans at the time of a data freeze (December, 2020) of the Dominantly Inherited Alzheimer Network (DIAN) study. Controls from the two studies were combined into a single group. All DIAN study participants had genetic testing to determine PSEN1, PSEN2, or APP mutation status. APOE genotype was determined from blood samples. CSF samples were collected in a subset of ABC-DS and DIAN participants and the ratio of amyloid β42 (Aβ42) to Aβ40 (Aβ42/40) was measured to evaluate its Spearman's correlation with amyloid PET. Global PET amyloid burden was compared with regards to cognitive status, APOE ɛ4 status, sex, age, and estimated years to symptom onset. We further analysed amyloid PET deposition by autosomal dominant mutation type. We also assessed regional patterns of amyloid accumulation by estimated number of years to symptom onset. Within a subset of participants the relationship between amyloid PET and CSF Aβ42/40 was evaluated.192 individuals with Down syndrome and 33 sibling controls from the ABC-DS study and 265 carriers of autosomal dominant Alzheimer's disease mutations and 169 non-carrier familial controls from the DIAN study were included in our analyses. PET amyloid centiloid and CSF Aβ42/40 were negatively correlated in carriers of autosomal dominant Alzheimer's disease mutations (n=216; r=-0·565; p0·0001) and in people with Down syndrome (n=32; r=-0·801; p0·0001). There was no difference in global PET amyloid burden between asymptomatic people with Down syndrome (mean 18·80 centiloids [SD 28·33]) versus asymptomatic mutation carriers (24·61 centiloids [30·27]; p=0·11) and between symptomatic people with Down syndrome (77·25 centiloids [41·76]) versus symptomatic mutation carriers (69·15 centiloids [51·10]; p=0·34). APOE ɛ4 status and sex had no effect on global amyloid PET deposition. Amyloid deposition was elevated significantly earlier in mutation carriers than in participants with Down syndrome (estimated years to symptom onset -23·0 vs -17·5; p=0·0002). PSEN1 mutations primarily drove this difference. Early amyloid accumulation occurred in striatal and cortical regions for both mutation carriers (n=265) and people with Down syndrome (n=128). Although mutation carriers had widespread amyloid accumulation in all cortical regions, the medial occipital regions were spared in people with Down syndrome.Despite minor differences, amyloid PET changes were similar between people with autosomal dominant Alzheimer's disease versus Down syndrome and strongly supported early amyloid dysregulation in individuals with Down syndrome. Individuals with Down syndrome aged at least 35 years might benefit from early intervention and warrant future inclusion in clinical trials, particularly given the relatively high incidence of Down syndrome.The National Institute on Aging, Riney and Brennan Funds, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the German Center for Neurodegenerative Diseases, and the Japan Agency for Medical Research and Development.

Introduction: Cerebrovascular disease (CVD) and neuropsychiatric symptoms (NPS) are common in older adults and are independently associated with cognitive impairment. In addition, vascular depression (a late-life depression) is hypothesized to be associated with cerebrovascular pathology. Hypothesis: CVD pathology imaging biomarkers (e.g., white matter hyperintensities (WMH), infarctions) are associated with depression and anxiety, and both (depression/anxiety and CVD imaging biomarkers) are independently associated with mild cognitive impairment (MCI). Methods: This cross-sectional study included 1739 Mayo Clinic Study of Aging participants (≥50 years old) without dementia, with comprehensive cognitive evaluations and available data on the Beck Depression Inventory II (BDI), the Beck Anxiety Inventory (BAI) and imaging CVD biomarkers via FLAIR-MRI (i.e., WMH% of total intracranial volume (TIV) and brain infarctions). We used linear and logistic regression models to examine the associations adjusting for age, sex, education, and apolipoprotein E ε4 status. Results: Participants’ mean age (SD) was 71.11 (10.61) years (53.3% males). Higher WMH% TIV burden was significantly associated with higher BDI (b= 0.082, 95%CI: 0.031, 0.133), p=0.002) and BAI scores (b= 0.088, 95%CI: 0.037, 0.140), p=0.001); the presence of infarctions was also associated with a higher BDI score. Both WMH %TIV burden (OR: 1.20 (95%CI:1.05, 1.38), p=0.008) and BDI score (OR: 1.38 (95%CI:1.21, 1.57), p Conclusions: CVD imaging biomarkers and NPS, as measured by BDI and BAI scores, could represent two distinct processes associated with cognitive impairment. Studies are ongoing to further examine these associations and delineate how CVD, NPS, and other pathophysiology processes (e.g., Alzheimer’s disease) interact and are associated with cognitive impairment.

Speech-in-noise performance is fundamental to daily communications and comprehensive characterization is needed. We studied 590 dementia-free participants aged 70-84 years, including 428 hearing-impaired participants from the Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study baseline (2018-19), which is a randomized controlled trial partially nested within the Atherosclerosis Risk in Communities (ARIC) Study, and 162 normal-hearing ARIC Visit 6/7 (2016-17/2018-19) participants. The Quick Speech-in-Noise (QuickSIN) test was used to measure speech-in-noise performance. Predictors included (1) Four-frequency better-ear pure-tone average (PTA); (2) Magnetic resonance imaging (MRI) measures (total and lobar volumes, diffusion tensor imaging, white matter hyperintensities); (3) Global and domain-specific (language, memory, executive function) cognitive performance. All predictors were standardized to Z-scores. We used multivariable-adjusted linear regression, adjusting for demographic and disease covariates. PTA and cognitive performance, but not MRI measures, were independently associated with speech-in-noise performance, with PTA explaining the largest variance, indicating the promising role of hearing aids.

Prepared by instructors and curriculum specialists, this course of study was designed to meet the individual needs of the dropout and/or hard-core unemployed youth by providing training as a service station attendant and light automotive maintenance mechanic. The achievement level of each student is determined at entry, and small instructional units are used to provide continuing positive reinforcement to minimize frustration. Training in this area is conducted in a public service station operated by the Work Opportunity Center. Instruction is provided in driveway sales, lubrication engine tune-up, brake work, and other repair and maintenance tasks short of major overhaul or body work. Students may receive such related instruction as mathematics, sales, accounting, and communications at the Center in addition to the related units taught at the station. Brief descriptions of other instructional areas, teaching techniques, material utilization, motivational devices, and case studies are appended. Related materials are available as VT 011 518-VT 011 533 in this issue. (GR)

Neurofilament light chain (NfL) is a promising fluid biomarker of disease progression for various cerebral proteopathies. Here we leverage the unique characteristics of the Dominantly Inherited Alzheimer Network and ultrasensitive immunoassay technology to demonstrate that NfL levels in the cerebrospinal fluid (n = 187) and serum (n = 405) are correlated with one another and are elevated at the presymptomatic stages of familial Alzheimer's disease. Longitudinal, within-person analysis of serum NfL dynamics (n = 196) confirmed this elevation and further revealed that the rate of change of serum NfL could discriminate mutation carriers from non-mutation carriers almost a decade earlier than cross-sectional absolute NfL levels (that is, 16.2 versus 6.8 years before the estimated symptom onset). Serum NfL rate of change peaked in participants converting from the presymptomatic to the symptomatic stage and was associated with cortical thinning assessed by magnetic resonance imaging, but less so with amyloid-β deposition or glucose metabolism (assessed by positron emission tomography). Serum NfL was predictive for both the rate of cortical thinning and cognitive changes assessed by the Mini-Mental State Examination and Logical Memory test. Thus, NfL dynamics in serum predict disease progression and brain neurodegeneration at the early presymptomatic stages of familial Alzheimer's disease, which supports its potential utility as a clinically useful biomarker. Fil: Preische, Oliver. German Center For Neurodegenerative Disease; Alemania. Eberhard Karls Universität Tübingen.; Alemania Fil: Schultz, Stephanie A.. Washington University in St. Louis; Estados Unidos Fil: Apel, Anja. German Center For Neurodegenerative Disease; Alemania. Eberhard Karls Universität Tübingen.; Alemania Fil: Kuhle, Jens. University of Basel; Suiza Fil: Kaeser, Stephan A.. German Center For Neurodegenerative Disease; Alemania. Eberhard Karls Universität Tübingen.; Alemania Fil: Barro, Christian. University of Basel; Suiza Fil: Gräber, Susanne. German Center For Neurodegenerative Disease; Alemania Fil: Kuder Buletta, Elke. German Center For Neurodegenerative Disease; Alemania Fil: LaFougere, Christian. German Center For Neurodegenerative Disease; Alemania Fil: Laske, Christoph. German Center For Neurodegenerative Disease; Alemania. Eberhard Karls Universität Tübingen.; Alemania Fil: Vöglein, Jonathan. German Center for Neurodegenerative Diseases; Alemania. Ludwig Maximilians Universitat; Alemania Fil: Levin, Johannes. German Center for Neurodegenerative Diseases; Alemania. Ludwig Maximilians Universitat; Alemania Fil: Masters, Colin. University of Melbourne; Australia Fil: Martins, Ralph. Edith Cowan University; Australia. Macquarie University; Australia Fil: Schofield, Peter. Neuroscience Research Australia; Australia. University of New South Wales; Australia Fil: Rossor, Martin N.. University College London; Estados Unidos Fil: Graff Radford, Neill. Mayo Clinic Jacksonville. Department of Neurology; Estados Unidos Fil: Salloway, Stephen. Brown University; Estados Unidos Fil: Ghetti, Bernardino. Indiana University. School of Medicine; Estados Unidos Fil: Ringman, John M.. Indiana University. School of Medicine; Estados Unidos Fil: Noble, James M.. Columbia University; Estados Unidos Fil: Chhatwal, Jasmeer. Harvard Medical School; Estados Unidos Fil: Goate, Alison. Icahn School of Medicine at Mount Sinai. Department of Neuroscience; Estados Unidos Fil: Benzinger, Tammie L. S.. Washington University in St. Louis; Estados Unidos Fil: Morris, John. Washington University in St. Louis; Estados Unidos Fil: Bateman, Randall J.. Washington University in St. Louis; Estados Unidos Fil: Wang, Guoqiao. Washington University in St. Louis; Estados Unidos Fil: Fagan, Anne M.. Washington University in St. Louis; Estados Unidos Fil: McDade, Eric M.. Washington University in St. Louis; Estados Unidos Fil: Gordon, Brian. Washington University in St. Louis; Estados Unidos Fil: Jucker, Mathias. University of Tübingen. Hertie Institute for Clinical Brain Research. Department of Cellular Neurology and Department of Psychiatry and Psychotherapy; Alemania. German Center For Neurodegenerative Disease; Alemania Fil: Allegri, Ricardo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina

We investigated the cross-sectional associations of speech-in-noise performance with magnetic resonance imaging brain volumes among 588 cognitively normal participants (77±4 years, 56% female) from the Aging and Cognitive Health Evaluation in Elders Study (randomized trial embedded in the Atherosclerosis Risk in Communities (ARIC) Study) baseline in 2018-19 (N=427, with hearing loss) and ARIC (N=161, normal hearing) Visit 6/7 in 2016-17/2018-19. Central auditory processing was measured by Quick Speech-in-Noise (QuickSIN) test; range: 0 to 30, lower scores=worse performance. In models adjusted for demographic and disease covariates, every 5-point decrease in QuickSIN score was associated with smaller volumes of the temporal lobe overall (-0.07SD, 95% CI:-0.13,-0.01) as well as subregions including but not limited to those important for auditory processing (amygdala:-0.13SD, 95% CI:-0.21,-0.04; middle temporal gyrus:-0.08SD, 95% CI:-0.15,-0.00; superior temporal gyrus:-0.08SD, 95% CI:-0.15,-0.01). Further research is needed to understand the mechanisms underlying these observed associations.

Introduction We have previously shown that older adults with excessive daytime sleepiness (EDS) appear to be more vulnerable to longitudinal amyloid PET accumulation before the onset of the dementia. It remains unclear whether this vulnerability is specific to amyloid or extends to other biomarkers of Alzheimer’s disease pathology, or axonal integrity and inflammation, which can also contribute to neurodegeneration and cognitive changes. Methods For this cross-sectional analysis, we identified 260 cognitively unimpaired adults (>60 years old) without neurologic disorder who underwent CSF quantification of AD biomarkers (CSF Aβ-42, p-tau181, p-tau217) along with at least one other biomarker of interest (neurofilament light chain [NfL], IL-6, IL-10, and TNF-α) from the Mayo Clinic Study of Aging – a longitudinal population-based cohort in Olmsted County, Minnesota. CSF biomarkers were available in 251-260 individuals, depending on the biomarker. We fit linear regression models to assess whether the CSF biomarkers were associated with sleepiness as measured by the Epworth Sleepiness Scale (ESS), after controlling for age, sex, APOE4 genotype, BMI, hypertension, dyslipidemia, and OSA diagnosis (by chart review). Results Higher ESS scores were independently associated with higher CSF IL-6 and NfL, but not with the other biomarkers in the whole sample. For every single-point increase in the ESS score, there was a .008 ([95% CI .001-.016], p=0.033) increase in the log of IL-6 and .01 ([95% CI .002-.018], p=0.016) increase in the log of NfL. A sensitivity analysis showed a correlation between ESS scores and log of p-tau/Aβ-42 ratio only in participants with abnormal ratio (>0.023), after controlling for APOE4 (partial r=.27, p=039). Conclusion Our results corroborate previous literature suggesting that higher inflammatory milieu reflected by increased CSF IL-6 is associated with sleepiness. The association between NfL and sleepiness suggests that sleepiness may be related to disturbed connectivity due to axonal damage. Alternatively, NfL may be a surrogate of active axonal injury associated with more disrupted sleep. A correlation between sleepiness and CSF p-tau/ab-42 ratio was only seen in patients with abnormal ratio, suggesting a stronger association between sleepiness and AD pathology as the disease progresses, possibly because AD pathology worsens sleep quality and/or vice-versa. Support (If Any) NIH/NIA

Genome–wide association studies (GWAS) have revealed a plethora of putative susceptibility genes for Alzheimer’s disease (AD), with the sole exception of APOE gene unequivocally validated in independent study. Considering that the etiology of complex diseases like AD could depend on functional multiple genes interaction network, here we proposed an alternative GWAS analysis strategy based on (i) multivariate methods and on a (ii) telescope approach, in order to guarantee the identification of correlated variables, and reveal their connections at three biological connected levels. Specifically as multivariate methods, we employed two machine learning algorithms and a genetic association test and we considered SNPs, Genes and Pathways features in the analysis of two public GWAS dataset (ADNI-1 and ADNI-2). For each dataset and for each feature we addressed two binary classifications tasks: cases vs. controls and the low vs. high risk of developing AD considering the allelic status of APOEe4. This complex strategy allowed the identification of SNPs, genes and pathways lists statistically robust and meaningful from the biological viewpoint. Among the results, we confirm the involvement of TOMM40 gene in AD and we propose GRM7 as a novel gene significantly associated with AD.

International audience; Development of tau-based therapies for Alzheimer's disease requires an understanding of the timing of disease-related changes in tau. We quantified the phosphorylation state at multiple sites of the tau protein in cerebrospinal fluid markers across four decades of disease progression in dominantly inherited Alzheimer's disease. We identified a pattern of tau staging where site-specific phosphorylation changes occur at different periods of disease progression and follow distinct trajectories over time. These tau phosphorylation state changes are uniquely associated with structural, metabolic, neurodegenerative and clinical markers of disease, and some (p-tau217 and p-tau181) begin with the initial increases in aggregate amyloid-β as early as two decades before the development of aggregated tau pathology. Others (p-tau205 and t-tau) increase with atrophy and hypometabolism closer to symptom onset. These findings provide insights into the pathways linking tau, amyloid-β and neurodegeneration, and may facilitate clinical trials of tau-based treatments.

Parietal cortex RNA-sequencing (RNA-seq) data were generated from individuals with and without Alzheimer disease (AD; ncontrol = 13; nAD = 83) from the Knight Alzheimer Disease Research Center (Knight ADRC). Using this and an independent (Mount Sinai Brain Bank (MSBB)) AD RNA-seq dataset, cortical circular RNA (circRNA) expression was quantified in the context of AD. Significant associations were identified between circRNA expression and AD diagnosis, clinical dementia severity and neuropathological severity. It was demonstrated that most circRNA-AD associations are independent of changes in cognate linear messenger RNA expression or estimated brain cell-type proportions. Evidence was provided for circRNA expression changes occurring early in presymptomatic AD and in autosomal dominant AD. It was also observed that AD-associated circRNAs co-expressed with known AD genes. Finally, potential microRNA-binding sites were identified in AD-associated circRNAs for miRNAs predicted to target AD genes. Together, these results highlight the importance of analyzing non-linear RNAs and support future studies exploring the potential roles of circRNAs in AD pathogenesis.

Background: Both subjective cognitive decline (SCD) and a family history of Alzheimer's disease (AD) portend risk of brain abnormalities and progression to dementia. Posterior default mode network (pDMN) connectivity is altered early in the course of AD. It is unclear whether SCD predicts similar outcomes in cognitively normal individuals with a family history of AD. Methods: We studied 124 asymptomatic individuals with a family history of AD (age 64 ± 5 years). Participants were categorized as having SCD if they reported that their memory was becoming worse (SCD+). We used extensive neuropsychological assessment to investigate five different cognitive domain performances at baseline (n = 124) and 1 year later (n = 59). We assessed interconnectivity among three a priori defined ROIs: pDMN, anterior ventral DMN, medial temporal memory system (MTMS), and the connectivity of each with the rest of brain. Results: Sixty-eight (55%) participants reported SCD. Baseline cognitive performance was comparable between groups (all false discovery rate-adjusted p values >.05). At follow-up, immediate and delayed memory improved across groups, but the improvement in immediate memory was reduced in SCD+ compared with SCD− (all false discovery rate–adjusted p values −, SCD+ subjects showed increased pDMN–MTMS connectivity (false discovery rate–adjusted p

INTRODUCTION: We sought to establish the relationships between standard post mortem measures of AD neuropathology and ante mortem [(11)C]PIB-PET analyzed with the Centiloid (CL) method, a standardized scale for Aβ-PET quantification. METHODS: Four centers contributed 179 participants encompassing a broad range of clinical diagnoses, PET data and autopsy findings. RESULTS: CL values increased with each CERAD neuritic plaque score increment (median −3 CL for no plaques, 92 CL for frequent plaques) and non-linearly with Thal Aβ phases (increases were detected starting at phase 2) with overlap between scores/phases. Findings were comparable across sites and when restricted to 56 patients who died within 2 years of PET. A threshold of 12.2 CL detected CERAD moderate-to-frequent neuritic plaques (AUC=0.910, Sensitivity=89.2%, Specificity=86.4%) while 24.4 CL identified intermediate-to-high AD neuropathological changes (AUC=0.894, Sensitivity=84.1%, Specificity=87.9%). DISCUSSION: Our study demonstrated the robustness of a multi-site Centiloid [(11)C]PIBPET study and established a range of pathology-based CL thresholds.

Introduction: Accelerated cognitive decline is influenced by vascular aging. Arterial stiffness and pressure amplification, measures of vascular aging, are associated with lower cognitive performance though their association with cognitive domains has been understudied. Hypothesis: Arterial stiffness and pressure amplification are associated with lower global and domain-specific cognition among a sample of Caucasian and African American (AA) older adults. Methods: In a cross-sectional study of 4618 members from visit 5 (2011-2013) of ARIC (mean age: 75 years, 41% men, 20% AA), we measured arterial stiffness (carotid-femoral pulse wave velocity (cfPWV)) and pressure amplification (pulse pressure amplification (PPA), central pulse pressure (cPP) and carotid systolic blood pressure (cSBP)) using the Omron VP-1000 Plus device. Race-specific 25th percentile cut points were estimated for each measure. Domain-specific cognitive function was examined using the Delayed Word Recall Test (memory), Digit Symbol Substitution Test (executive function/processing speed), and Word Fluency Test (language). Test-specific z scores were calculated from sample means and standard deviations. A global cognition z score was generated by averaging the test-specific z scores. Linear regression was used to estimate the associations between race-specific 25th percentile dichotomies for arterial stiffness and pressure amplification measures with test-specific and global cognition z scores, adjusted for age, sex, education, ApoE4, heart rate, smoking and body mass index. Results: Among AAs, there was no significant association between measures of arterial stiffness and pressure amplification with either global or the domain-specific measures of cognition. Among Caucasians, all measures of arterial stiffness and pressure amplification were associated with lower global cognitive z scores (cfPWV: Beta (β) =-0.11, 95% Confidence Interval (CI): -0.19, -0.04; PPA: β=-0.11, 95% CI: -0.19, -0.03; cPP: β=-0.11, 95% CI: -0.18, -0.04; cSBP: β=-0.12, 95% CI: -0.20, -0.05). All measures of arterial stiffness and pressure amplification also were associated with lower executive function/processing speed (cfPWV: β=-0.09, 95% CI: -0.16, -0.03; PPA: β=-0.15, 95% CI: -0.22, -0.08; cPP: β=-0.14, 95% CI: -0.21, -0.07; cSBP: β=-0.13, 95% CI: -0.20, -0.07). High cfPWV was associated with lower memory (β=-0.12, 95% CI: -0.20, -0.04); and high cSBP was associated with lower language (β=-0.12, 95% CI: -0.20, -0.04). Conclusions: Arterial stiffness and measures of pressure amplification are inversely associated with global and domain-specific cognition in Caucasian older adults, but not in a smaller sample of AAs. Further study of the role of modifiable components of arterial aging on the preservation of cognition, particularly executive function/psychomotor speed, in older adulthood is warranted.

Background: As a high-flow, low-impedance organ, the brain is sensitive to excessive pressure and flow pulsatility. Increased pulsatility and arterial stiffness are hypothesized to contribute to cerebral microvascular damage linked to cognitive impairment. The association of arterial stiffness with mild cognitive impairment (MCI) and dementia in a biethnic population is not well characterized, and the association of pressure amplification with MCI and dementia is relatively unexplored. Objectives: To quantify the cross-sectional association of arterial stiffness, measured by aortic pulse wave velocity (PWV), and pressure amplification with MCI and dementia in a biethnic population of older adults. Methods: We included 4,945 adults (2,903 females; 1,069 African Americans; mean age 75 years) from the population-based ARIC-NCS. The Omron VP-1000 plus system was used to measure arterial stiffness (carotid-femoral PWV (cfPWV)) and pressure amplification measures (central systolic blood pressure (cSBP), central pulse pressure (cPP), and pulse pressure amplification (PPA)). A neurologist and neuropsychologist classified MCI and dementia using psychometric assessments, medical history, cerebral magnetic resonance imaging, and physical examinations, with adjudication by a third reviewer. We used multinomial logistic regression to evaluate associations of race-specific 25th percentile cut points of PWV and pressure amplification with normal cognition (reference), MCI and dementia. We stratified by race and adjusted for age, sex, and heart rate, ApoE4, education, smoking status, and study center. Results: There were 760 Caucasians with MCI and 110 with dementia, and 201 African Americans with MCI and 47 with dementia. Among Caucasians, those with lower PPA had a higher prevalence of dementia, odds ratio (OR)=1.84 (95% confidence interval (CI): 1.15, 2.97), comparing participants below the 25th percentile to those above it, and those with higher cSBP had a higher prevalence of MCI, OR=1.33 (95% CI: 1.09, 1.63), comparing participants above the 75th percentile to those below it. Also among Caucasians, those with higher cPP had a higher prevalence of MCI, OR=1.25 (95%CI: 1.01, 1.55), and dementia, OR=1.66 (95% CI: 1.00, 2.73), comparing participants above the 75th percentile to those below it. There were no statistically significant associations with cfPWV, among African Americans, and no evidence for effect modification by hypertension or diabetes. Conclusion: Arterial stiffness and components of pressure amplification were associated with MCI and dementia in Caucasians but not in African Americans, possibly due to the limited sample size. Longitudinal characterization of the observed associations is warranted to determine whether these measures are independent predictors of MCI and dementia among Caucasian and African American older adults.

Structural imaging based on magnetic resonance is an integral part of the clinical assessment of patients with suspected Alzheimer dementia. Prospective data on the natural history of change in structural markers from preclinical to overt stages of Alzheimer disease are radically changing how the disease is conceptualized, and will influence its future diagnosis and treatment. Atrophy of medial temporal structures is now considered to be a valid diagnostic marker at the mild cognitive impairment stage. Structural imaging is also included in diagnostic criteria for the most prevalent non-Alzheimer dementias, reflecting its value in differential diagnosis. In addition, rates of whole-brain and hippocampal atrophy are sensitive markers of neurodegeneration, and are increasingly used as outcome measures in trials of potentially disease-modifying therapies. Large multicenter studies are currently investigating the value of other imaging and nonimaging markers as adjuncts to clinical assessment in diagnosis and monitoring of progression. The utility of structural imaging and other markers will be increased by standardization of acquisition and analysis methods, and by development of robust algorithms for automated assessment.

The objective of this study was to investigate the cross-sectional associations of atrial fibrillation with neuroimaging measures of cerebrovascular disease and Alzheimer’s disease-related pathology, and their interaction with cognitive impairment. MRI scans of non-demented individuals (n=1044) from the population-based Mayo Clinic Study of Aging were analyzed for infarctions, total grey matter, hippocampal and white matter hyperintensity volumes. A subset of 496 individuals underwent FDG and C-11 Pittsburgh compound B (PiB) PET scans. We assessed the associations of atrial fibrillation with i) categorical MRI measures (cortical and subcortical infarctions) using multivariable logistic regression models, and with ii) continuous MRI measures ( hippocampal, total grey matter, and white matter hyperintensity volumes) and FDG-PET and PiB-PET measures using multivariable linear regression models, and adjusting for confounders. Among participants who underwent MRI (median age, 77.8, 51.6% male), 13.5% had atrial fibrillation. Presence of atrial fibrillation was associated with subcortical infarctions (odds ratio [OR], 1.83; p=0.002), cortical infarctions (OR, 1.91; p=0.03), total grey matter volume (Beta [β], -.025, p

The Dominantly Inherited Alzheimer's Network Trials Unit (DIAN-TU) was formed to direct the design and management of interventional therapeutic trials of international DIAN and autosomal dominant Alzheimer's disease (ADAD) participants. The goal of the DIAN-TU is to implement safe trials that have the highest likelihood of success while advancing scientific understanding of these diseases and clinical effects of proposed therapies. The DIAN-TU has launched a trial design that leverages the existing infrastructure of the ongoing DIAN observational study, takes advantage of a variety of drug targets, incorporates the latest results of biomarker and cognitive data collected during the observational study, and implements biomarkers measuring Alzheimer's disease (AD) biological processes to improve the efficiency of trial design. The DIAN-TU trial design is unique due to the sophisticated design of multiple drugs, multiple pharmaceutical partners, academics servings as sponsor, geographic distribution of a rare population and intensive safety and biomarker assessments. The implementation of the operational aspects such as home health research delivery, safety magnetic resonance imagings (MRIs) at remote locations, monitoring clinical and cognitive measures, and regulatory management involving multiple pharmaceutical sponsors of the complex DIAN-TU trial are described.