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Early diagnosis of mild cognitive impairment (MCI) and mild Alzheimer’s disease (AD) dementia is crucial for effective disease management and optimizing patient outcomes. We sought to better understand the MCI and mild AD dementia medical journey from the perspective of patients, care partners, and physicians. We conducted online surveys in the United States among patients/care partners and physicians in 2021. 103 patients with all-cause MCI or mild AD dementia aged 46–90 years, 150 care partners for someone with all-cause MCI or mild AD dementia, and 301 physicians (101 of which were primary care physicians, [PCPs]) completed surveys. Most patient/care partners reported that experiencing forgetfulness (71%) and short-term memory loss (68%) occurred before talking to a healthcare professional. Most patients (73%) followed a common medical journey, in which the initial discussion with a PCP took place 15 months after symptom onset. However, only 33% and 39% were diagnosed and treated by a PCP, respectively. Most (74%) PCPs viewed themselves as coordinators of care for their patients with MCI and mild AD dementia. Over one-third (37%) of patients/care partners viewed PCPs as the care coordinator. PCPs play a vital role in the timely diagnosis and treatment of MCI and mild AD dementia but often are not considered the care coordinator. For the majority of patients, the initial discussion with a PCP took place 15 months after symptom onset; therefore, it is important to educate patients/care partners and PCPs on MCI and AD risk factors, early symptom recognition, and the need for early diagnosis and treatment. PCPs could improve patient care and outcomes by building their understanding of the need for early AD diagnosis and treatment and improving the efficiency of the patient medical journey by serving as coordinators of care. Alzheimer’s disease (AD) is not a normal part of aging, but many people develop AD as they age, and it is the seventh leading cause of death in the US. AD is a neurological condition that begins as mild cognitive impairment (MCI) or mild AD dementia. To understand the medical journey of patients with MCI or mild AD dementia, we surveyed 103 patients with MCI or mild AD dementia, 150 care partners, and 301 doctors. Patients had several symptoms before talking to a doctor, including forgetfulness and short-term memory loss; most patients (64%) first discussed these symptoms with a primary care physician (PCP) on average 15 months later. However, most patients were not diagnosed or treated by a PCP for MCI or mild AD dementia. We asked patients/care partners who they believe is the coordinator of their care for MCI and mild AD dementia. Thirty-seven percent felt the PCP was the coordinator of care. Most surveyed PCPs (74%) considered themselves to be the coordinator of care for their patients with MCI or mild AD dementia. In conclusion, PCPs play a key role in the care of patients with MCI and mild AD dementia. It is important for patients and care partners to understand the symptoms of MCI and mild AD dementia, and the need to get a diagnosis and treatment soon after symptoms appear. PCPs can play an important role in early diagnosis and treatment and serve as coordinators of care for their patients with MCI and mild AD dementia.

In the present study, we tested the hypothesis that higher amyloid-beta (Aβ) burden at baseline is associated with greater longitudinal decline in body mass index (BMI) in clinically normal adults. Participants from the Harvard Aging Brain Study (n = 312) and the Alzheimer's Disease Neuroimaging Initiative (n = 336) underwent Aβ positron emission tomography at baseline. BMI was assessed longitudinally over a median of >4 years. Linear mixed models showed that higher baseline Aβ burden was significantly associated with greater decline in BMI in both the Harvard Aging Brain Study (t = −1.93; p = 0.05) and Alzheimer's Disease Neuroimaging Initiative cohorts (t = −2.54; p = 0.01), after adjusting for covariates, including cognitive performance and depressive symptoms. In addition, the association of Aβ burden with longitudinal decline in BMI persisted in both cohorts after excluding participants with diabetes/endocrine disturbances and participants classified as underweight or obese (BMI 30). These findings suggest that decline in BMI in clinically normal adults may be an early manifestation related to cerebral amyloidosis that precedes objective cognitive impairment. Therefore, unintentional BMI decline in otherwise healthy individuals might alert clinicians to increased risk of Alzheimer's disease.

Physical activity (PA) promotes resilience with respect to cognitive decline, although the underlying mechanisms are not well understood. We examined the associations between objectively measured PA and resting-state functional connectivity magnetic resonance imaging (rs-fcMRI) across seven anatomically distributed neural networks.rs-fcMRI, amyloid beta (Aβ) positron emission tomography (PET), PA (steps/day × 1 week), and longitudinal cognitive (Preclinical Alzheimer's Cognitive Composite) data from 167 cognitively unimpaired adults (ages 63 to 90) were used. We used linear and linear mixed-effects regression models to examine the associations between baseline PA and baseline network connectivity and between PA, network connectivity, and longitudinal cognitive performance.Higher PA was associated selectively with greater connectivity in three networks previously associated with cognitive decline (default, salience, left control). This association with network connectivity accounted for a modest portion of PA's effects on Aβ-related cognitive decline.Although other mechanisms are likely present, PA may promote resilience with respect to Aß-related cognitive decline, partly by increasing connectivity in a subset of cognitive networks.

Introduction Immune dysregulation is implicated in neurodegeneration and altered cytokine levels are seen in people with dementia. However, whether cytokine levels are predictive of cognitive decline in cognitively unimpaired (CU) elderly, especially in the setting of elevated amyloid beta (Aβ), remains unclear. Methods We measured nine cytokines in the baseline plasma of 298 longitudinally followed CU elderly and assessed whether these measures were associated with cognitive decline, alone or synergistically with Aβ. We next examined associations between cytokine levels and neuroimaging biomarkers of Aβ/tau/neurodegeneration. Results Higher IL-12p70 was associated with slower cognitive decline in the setting of higher Aβ (false discovery rate [FDR] = 0.0023), whereas higher IFN-γ was associated with slower cognitive decline independent of Aβ (FDR = 0.013). Higher IL-12p70 was associated with less tau and neurodegeneration in participants with higher Aβ. Discussion Immune dysregulation is implicated in early-stage cognitive decline, and greater IL-12/IFN-γ axis activation may be protective against cognitive decline and early-stage AD progression.

Highlights • Degradation of the DMN/SAL network axis is related to amyloid burden in symptomatic individuals. • The effect size is equal to change on the MMSE and change in hippocampal volume. • The effect is distinct from change in MMSE or hippocampal volume. • The effect is unique to the anti-correlated DMN/SAL network axis. • This result are encouraging for the use of rs-fcMRI in clinical trials., Resting-state functional connectivity MRI (rs-fcMRI) is a non-invasive imaging technique that has come into increasing use to understand disrupted neural network function in neuropsychiatric disease. However, despite extensive study over the past 15 years, the development of rs-fcMRI as a biomarker has been impeded by a lack of reliable longitudinal rs-fcMRI measures. Here we focus on longitudinal change along the Alzheimer's disease (AD) trajectory and demonstrate the utility of Template Based Rotation (TBR) in detecting differential longitudinal rs-fcMRI change between higher and lower amyloid burden individuals with mildly impaired cognition. Specifically, we examine a small (N = 24), but densely sampled (~5 observations over ~3 years), cohort of symptomatic individuals with serial rs-fcMRI imaging and PiB-PET imaging for β-amyloid pathology. We observed longitudinal decline of the Default Mode and Salience network axis (DMN/SAL) among impaired individuals with high amyloid burden. No other networks showed differential change in high vs. low amyloid individuals over time. The standardized effect size of AD related DMN/SAL change is comparable to the standardized effect size of amyloid-related change on the mini-mental state exam (MMSE) and hippocampal volume (HV). Last, we show that the AD-related change in DMN/SAL connectivity is almost completely independent of change on MMSE or HV, suggesting that rs-fcMRI is sensitive to an aspect of AD progression that is not captured by these other measures. Together these analyses demonstrate that longitudinal rs-fcMRI using TBR can capture disease-relevant network disruption in a clinical population.

The shared role of amyloid-β (Aβ) deposition in cerebral amyloid angiopathy (CAA) and Alzheimer disease (AD) is arguably the clearest instance of crosstalk between neurodegenerative and cerebrovascular processes. The pathogenic pathways of CAA and AD intersect at the levels of Aβ generation, its circulation within the interstitial fluid and perivascular drainage pathways and its brain clearance, but diverge in their mechanisms of brain injury and disease presentation. Here, we review the evidence for and the pathogenic implications of interactions between CAA and AD. Both pathologies seem to be driven by impaired Aβ clearance, creating conditions for a self-reinforcing cycle of increased vascular Aβ, reduced perivascular clearance and further CAA and AD progression. Despite the close relationship between vascular and plaque Aβ deposition, several factors favour one or the other, such as the carboxy-terminal site of the peptide and specific co-deposited proteins. Amyloid-related imaging abnormalities that have been seen in trials of anti-Aβ immunotherapy are another probable intersection between CAA and AD, representing overload of perivascular clearance pathways and the effects of removing Aβ from CAA-positive vessels. The intersections between CAA and AD point to a crucial role for improving vascular function in the treatment of both diseases and indicate the next steps necessary for identifying therapies.

IMPORTANCE: In the absence of disease-modifying therapies for Alzheimer disease, there is a critical need to identify modifiable risk factors that may delay the progression of Alzheimer disease. OBJECTIVE: To examine whether physical activity moderates the association of β-amyloid (Aβ) burden with longitudinal cognitive decline and neurodegeneration in clinically normal individuals and to examine whether these associations are independent of vascular risk. DESIGN, SETTING, AND PARTICIPANTS: This longitudinal observational study included clinically normal participants from the Harvard Aging Brain Study. Participants were required to have baseline Aβ positron emission tomography data, baseline medical data to quantify vascular risk, and longitudinal neuropsychological and structural magnetic resonance imaging data. Data were collected from April 2010 to June 2018. Data were analyzed from August to December 2018. MAIN OUTCOMES AND MEASURES: Baseline physical activity was quantified with a pedometer (mean steps per day). Baseline Aβ burden was measured with carbon 11–labeled Pittsburgh Compound B positron emission tomography. Cognition was measured annually with the Preclinical Alzheimer Cognitive Composite (PACC; median [interquartile range] follow-up, 6.0 [4.3-6.3] years). Neurodegeneration was assessed with longitudinal structural magnetic resonance imaging (2 to 5 scans per participant; median [interquartile range] follow-up, 4.5 [3.0-5.0] years), with a focus on total gray matter volume and regional cortical thickness. Physical activity and Aβ burden were examined as interactive predictors of PACC decline and volume loss in separate linear mixed models, adjusting for age, sex, education, apolipoprotein E ε4 status, and, where appropriate, intracranial volume. Secondary models adjusted for vascular risk and its interaction with Aβ burden. RESULTS: Of the 182 included participants, 103 (56.6%) were female, and the mean (SD) age was 73.4 (6.2) years. In models examining PACC decline and volume loss, there was a significant interaction of physical activity with Aβ burden, such that greater physical activity was associated with slower Aβ-related cognitive decline (β, 0.03; 95% CI, 0.02-0.05; P

We examined the relationship of diabetes and hemoglobin A1C (A1C) to 2 common causes of dementia. The study included 1228 subjects who underwent annual clinical evaluations and a brain autopsy at death, as part of a Rush longitudinal cohort study of aging. A total of 433 subjects had A1C data available. Neuropathologic evaluations documented the size and location of infarcts. Modified silver stain-based Alzheimer disease (AD) measures included global and regional scores. We used regression analyses to examine associations of diabetes and A1C with overall and regional neuropathology. Diabetes [odds ratio (OR)=0.94; 95% confidence interval (CI), 0.73-1.20) and A1C (OR=0.83; 95% CI, 0.62-1.10) were not associated with global AD pathology across the brain, nor with overall or individual measures of neuropathology in mesial temporal or neocortical regions separately (all P>0.05). Diabetes was associated with a higher odds of any infarct (OR=1.43; 95% CI, 1.07-1.90), and particularly with gross (OR=1.53; 95% CI, 1.14-2.06) but not microinfarcts (P=0.06), and subcortical (OR=1.79; 95% CI, 1.34-2.39) but not cortical infarcts (P=0.83). In summary, we found no relationship of diabetes or A1C with global or regional AD pathology, including in the mesial temporal lobe. Diabetes is associated with gross subcortical infarcts. Our results suggest that the diabetes-dementia link is based on subcortical vascular pathology and not on regional AD pathology.

Type 2 diabetes (T2D) is recognized as being associated with pathological changes in the aged human brain, but the precise nature, extent, and underlying mechanisms involved in these changes are incompletely understood. Research groups have reported an increased risk for cognitive impairment and all-cause dementia, and vascular dementia in particular, but also clinical Alzheimer's disease (AD) among persons with T2D compared with those without it. In line with the clinical data and the fact that the most common cause of dementia is mixed pathology, two leading hypotheses that may explain how T2D contributes to dementia relate to cerebrovascular disease (CVD) and AD neuropathological changes (ADNC). Published data have shed light on these two hypotheses. On the one hand, clinicopathological studies have consistently demonstrated that T2D is associated with brain infarcts, especially small subcortical cerebral infarcts, which supports a role for CVD in relating T2D to dementia. On the other hand, the scientific literature to date does not clearly support a link between T2D and ADNC, which argues against a role for AD. This dissociation underscores emerging themes: the imprecision of clinical diagnoses, the impact of CVD on aging, and the importance of considering treatable conditions such as T2D in patients with cognitive impairment. Furthermore, other T2D-associated changes in the brain, even unrelated to AD or CVD, are possible mechanisms, and further research is needed.

Type 2 diabetes (T2D) and Alzheimer's disease (AD) are both highly prevalent diseases worldwide, and each is associated with high-morbidity and high-mortality. Numerous clinical studies have consistently shown that T2D confers a two-fold increased risk for a dementia, including dementia attributable to AD. Yet, the mechanisms underlying this relationship, especially nonvascular mechanisms, remain debated. Cerebral vascular disease (CVD) is likely to be playing a role. But increased AD neuropathologic changes (ADNC), specifically neuritic amyloid plaques (AP) and neurofibrillary tangles (NFT), are also posited mechanisms. The clinicopathological studies to date demonstrate T2D to be consistently associated with infarcts, particularly subcortical lacunar infarcts, but not ADNC, suggesting the association of T2D with dementia may largely be mediated through CVD. Furthermore, growing interest exists in insulin resistance (IR), particularly IR within the brain itself, which may be an associated but distinct phenomenon from T2D, and possibly itself associated with ADNC. Other mechanisms largely related to protein processing and efflux in the central nervous system with altered function in T2D may also be involved. Such mechanisms include islet amyloid polypeptide (or amylin) deposition, co-localized with beta-amyloid and found in more abundance in the AD temporal cortex, blood-brain barrier breakdown and dysfunction, potentially related to pericyte degeneration, and disturbance of brain lymphatics, both in the glial lymphatic system and the newly discovered discrete central nervous system lymph vessels. Medical research is ongoing to further disentangle the relationship of T2D to dementia in the ageing human brain.

To determine relationships of memory complaints to cognitive function and decline, incident dementia, and neurodegenerative and other neuropathologies, as well as the population-attributable risk for dementia in older black and white persons.A total of 4,015 community-based persons (28% black; 74% women; mean baseline age = 78 years) were enrolled in 1 of 4 longitudinal cohort studies, and another 2,937 in a population-based cohort. Memory scores, assessed using 2 questions (5-point Likert scales) were categorized as complaints present or absent. Global cognition and 5 cognitive domains were derived from annual neuropsychological tests. Dementia was assessed from these tests and additional data. Neuropathologic data were available for 1,350 deceased subjects with brain autopsies. Regression and mixed effects models were used to examine relationships of memory complaints to cognition and neuropathology.Baseline memory complaints (n = 1,310; 33% of 4,015) were associated with lower cognition and faster decline in all domains (global score estimate = -0.032, standard error = 0.004, p 0.0001), during a mean follow-up of 6 (standard deviation = 2) years. Persons with memory complaints had higher dementia risk (hazard ratio = 1.64, 95% confidence interval [CI] = 1.42-1.89) and odds of pathologic Alzheimer disease (odds ratio [OR] = 1.96, 95% CI = 1.51-2.54), neocortical Lewy bodies (OR = 2.47, 95% CI = 1.54-3.96), and other neurodegenerative pathologies. Results for dementia risk were similar among blacks and whites. Among 2,937 older persons in a population-based cohort with similar data, the population-attributable risk for incident dementia due to memory complaints was 14.0% (95% CI = 2.6-23.0), and did not vary between the black and white groups.Memory complaints are common in older black and white persons, and relate to cognitive decline, dementia risk, and neurodegenerative pathologies. Ann Neurol 2018;83:718-729.

We have previously hypothesized a biological pathway of activity-dependent synaptic plasticity proteins that addresses the dual genetic and environmental contributions to schizophrenia. Accordingly, variations in the immediate early gene EGR3, and its target ARC, should influence schizophrenia susceptibility. We used a pooled Next-Generation Sequencing approach to identify variants across these genes in U.S. populations of European (EU) and African (AA) descent. Three EGR3 and one ARC SNP were selected and genotyped for validation, and three SNPs were tested for association in a replication cohort. In the EU group of 386 schizophrenia cases and 150 controls EGR3 SNP rs1877670 and ARC SNP rs35900184 showed significant associations (p = 0.0078 and p = 0.0275, respectively). In the AA group of 185 cases and 50 controls, only the ARC SNP revealed significant association (p = 0.0448). The ARC SNP did not show association in the Han Chinese (CH) population. However, combining the EU, AA, and CH groups revealed a highly significant association of ARC SNP rs35900184 (p = 2.353 x 10(-7); OR [95% CI] = 1.54 [1.310-1.820]). These findings support previously reported associations between EGR3 and schizophrenia. Moreover, this is the first report associating an ARC SNP with schizophrenia and supports recent large-scale GWAS findings implicating the ARC complex in schizophrenia risk. These results support the need for further investigation of the proposed pathway of environmentally responsive, synaptic plasticity-related, schizophrenia genes.

In a genome-wide association study (GWAS) of late-onset Alzheimer's disease (AD), we found an association between common haplotypes of the GAB2 gene and AD risk in carriers of the apolipoprotein E (APOE) e4 allele, the major late-onset AD susceptibility gene. We previously proposed the use of fluorodeoxyglucose positron emission tomography (FDG-PET) measurements as a quantitative pre-symptomatic endophenotype, more closely related to disease risk than the clinical syndrome itself, to help evaluate putative genetic and non-genetic modifiers of AD risk. In this study, we examined the relationship between the presence or absence of the relatively protective GAB2 haplotype and PET measurements of regional-to-whole brain FDG uptake in several AD-affected brain regions in 158 cognitively normal late-middle-aged APOEe4 homozygotes, heterozygotes, and non-carriers. GAB2 haplotypes were characterized using Affymetrix Genome-Wide Human SNP 6.0 Array data from each of these subjects. As predicted, the possibly protective GAB2 haplotype was associated with higher regional-to-whole brain FDG uptake in AD-affected brain regions in APOEe4 carriers. While additional studies are needed, this study supports the association between the possibly protective GAB2 haplotype and the risk of late-onset AD in APOEe4 carriers. It also supports the use of brain-imaging endophenotypes to help assess possible modifiers of AD risk.

In this study, we assess 34 of the most replicated genetic associations for Alzheimer's disease (AD) using data generated on Affymetrix SNP 6.0 arrays and imputed at over 5.7 million markers from a unique cohort of over 1600 neuropathologically defined AD cases and controls (1019 cases and 591 controls). Testing the top genes from the AlzGene meta-analysis, we confirm the well-known association with APOE single nucleotide polymorphisms (SNPs), the CLU, PICALM and CR1 SNPs recently implicated in unusually large data sets, and previously implicated CST3 and ACE SNPs. In the cases of CLU, PICALM and CR1, as well as in APOE, the odds ratios we find are slightly larger than those previously reported in clinical samples, consistent with what we believe to be more accurate classification of disease in the clinically characterized and neuropathologically confirmed AD cases and controls.

Objective To investigate with fluorodeoxyglucose positron emission tomography whether regional reductions in the cerebral metabolic rate for glucose (CMRgl) previously found in cognitively healthy late-middle-aged apolipoprotein E ( APOE ) e4 carriers extend to members of the Latino Mexican American community. Design Prospective cohort study. Setting Banner Alzheimer's Institute, Phoenix, Arizona. Patients or Other Participants Eleven APOE e4 carriers and 16 noncarriers from Arizona's Latino community (mean [SD] age, 54.6 [6.4] years) matched for sex, mean age, and educational level and who were predominantly of self-designated Mexican origin. Main Outcome Measure A brain mapping algorithm was used to compare cross-sectional regional CMRgl in Latino APOE e4 carriers vs noncarriers. Results Participant groups had similar distributions for age, sex, education, family history of dementia, clinical ratings, and neuropsychological test scores. Latino APOE e4 carriers had lower CMRgl than the noncarriers in the posterior cingulate, precuneus, and parietal regions previously found to be preferentially affected in patients with Alzheimer disease (AD) and cognitively healthy non-Latino APOE e4 carriers. Additionally, the Latino APOE e4 carriers had lower CMRgl in the middle and anterior cingulate cortex, hippocampus, and thalamus. Conclusions This study provides support for the relationship between APOE e4 and risk of AD in Latino individuals. It illustrates the role of positron emission tomography as a presymptomatic endophenotype for the assessment of AD risk factors and supports the inclusion of Latino APOE e4 carriers in proof-of-concept studies using fluorodeoxyglucose PET to evaluate promising presymptomatic treatments in cognitively healthy carriers of this common AD susceptibility gene.

Corrigendum to “Association between GAB2 haplotype and higher glucose metabolism in Alzheimer's disease-affected brain regions in cognitively normal APOEe4 carriers” [NeuroImage 54/3 (2011) 1896–1902] Winnie S. Liang , Kewei Chen , Wendy Lee , Kunal Sidhar , Jason J. Corneveaux , April N. Allen , Amanda Myers , Stephen Villa , Bessie Meechoovet , Jeremy Pruzin , Daniel Bandy , Adam S. Fleisher , Jessica B.S. Langbaum , Matthew J. Huentelman , Kendall Jensen , Travis Dunckley , Richard J. Caselli , Susan Kaib , Eric M. Reiman a,b,c,j,⁎