Basic Science and Pathogenesis.

Background: Several viruses have been linked to Alzheimer disease (AD) by independent lines of evidence.

Method: Whole genome and whole exome sequences (WGS/WES) derived from brain (3,404 AD cases, 894 controls) and blood (15,612 AD cases, 24,544 controls) obtained from European ancestry (EU), African American (AA), Mexican (HMX), South Asian Indian (IND), and Caribbean Hispanic (CH) participants of the Alzheimer's Disease Sequencing Project (ADSP) and 276 AD cases 3,584 controls (all EU) from the Framingham Heart Study (FHS) that did not align to the human reference genome were aligned to viral reference genomes. A genome-wide association study (GWAS) for viral DNA load was conducted using PLINK software and regression models with covariates for sex, age, ancestry principal components, and tissue source.

Basic Science and Pathogenesis.

Background: Single-nucleus RNA sequencing (snRNAseq) allows for the dissection of the cell type-specific transcriptional profiles of tissue specimens. In this study, we compared gene expression in multiple brain cell types in brain tissue from Alzheimer disease (AD) cases with no or other co-existing pathologies including Lewy body disease (LBD) and vascular disease (VaD).

Method: We evaluated differential gene expression measured from single nucleus RNA sequencing (snRNAseq) data generated from the hippocampus region tissue donated by 11 BU ADRC participants with neuropathologically confirmed AD with or without a co-existing pathology (AD-only = 3, AD+VaD = 6, AD+LBD = 2).

Basic Science and Pathogenesis.

Background: Alzheimer's disease (AD) has both genetic and environmental risk factors. Gene-environment interaction may help explain some missing heritability. There is strong evidence for cigarette smoking as a risk factor for AD.

Basic Science and Pathogenesis.

Background: T-cell infiltration into the brain parenchyma is associated with hyperphosphorylated tau (p-tau) accumulation in neurodegenerative diseases. Chronic traumatic encephalopathy (CTE) is a progressive tauopathy caused by exposure to repetitive head impacts (RHI). CTE is defined by the perivascular accumulation of p-tau at the cortical sulcal depths and can be stratified into mild and severe pathological stages.

Basic Science and Pathogenesis.

Background: We previously discovered that Aβ accumulates in the cortical/supranuclear region of the lens in people with Alzheimer's Disease (AD) (Goldstein et al., 2003) and Down Syndrome (DS; (Moncaster et al., 2010).

Basic Science and Pathogenesis.

Background: Late-onset Alzheimer's disease (LOAD) is the leading cause of dementia and a major contributor to increased mortality. Recent human datasets have revealed many LOAD genetic risk factors that are correlated with the degree of AD burden. Further, the complexity and heterogeneity of LOAD appears to be promoted by interactions between genetics and environmental factors such as diet, sedentary behavior, and exposure to toxicants, like lead (Pb), cadmium (Cd), and arsenic (As).

Basic Science and Pathogenesis.

Background: Alzheimer's disease (AD) and AD-related dementias (ADRD) are modulated by gene-environment (GxE) interactions across the lifespan. Variants of specific genes increase AD risk and synergize with lifetime exposure to environmental toxicants ("exposome"), including neurotoxic metals (lead, Pb; cadmium, Cd) and metalloid (As). These metal/metalloid toxicants readily enter the body (e.

Basic Science and Pathogenesis.

Background: There is growing evidence that epigenetic age acceleration may predict late life cognitive decline and dementia, but it is unknown whether this is due to accelerated neurodegeneration or reduction in cognitive resilience. We examined the relationship between epigenetic clocks and domain specific neuropsychological (NP) factor scores, mild cognitive impairment (MCI), Alzheimer's Disease (AD), and all-cause dementia, before and after accounting for plasma total tau (t-tau), a marker of neurodegeneration.

Method: DNA methylation and plasma t-tau (Simoa assay; Quanterix) data from 2091 Framingham Heart Study Offspring cohort participants were generated from blood at the same Exam 8 visit (2005-2008).

Basic Science and Pathogenesis.

Background: Although the rate of Alzheimer's disease (AD) in African-ancestry (AA) Americans is higher than that of persons from European-ancestry (EA) populations, AA participants have been underrepresented in AD neuropathological studies.

Method: Utilizing the AD Research Centers (ADRC) infrastructure, we obtained AA donor pre-frontal cortex (PFC) tissue from brain repositories of 12 ADRC and generated bulk RNA sequencing (RNA-seq) data for 179 samples that met QC and inclusion criteria. Previously generated PFC RNAseq data were obtained for 28 additional AA donors from the Columbia University ADRC.

Clinical Manifestations.

Background: Subjective cognitive decline (SCD) is recognized to be in the Alzheimer's disease (AD) cognitive continuum. An international working group known as the SCD-initiative recently proposed "SCD plus" features, including report of memory problems, recent SCD relative to conversion, SCD over age 60, and consistent SCD over time, that increase the risk for future objective cognitive decline. These have not been fully assessed in a large community-based setting.

Clinical Manifestations.

Background: Exposure to repetitive head impacts (RHI) is associated with the neurodegenerative tauopathy chronic traumatic encephalopathy (CTE). There is substantial heterogeneity in the clinical presentation of CTE. Younger age of first exposure (AFE) to American football has not been associated with odds or severity of CTE.

Clinical Manifestations.

Background: Clinically meaningful cognitive impairment has typically been defined as a single impaired test score, but this approach is prone to false-positive errors. Examining two test scores at a lower threshold (i.e.

Clinical Manifestations.

Background: Traumatic encephalopathy syndrome (TES) is the proposed clinical syndrome of chronic traumatic encephalopathy (CTE), a neurodegenerative disease associated with repetitive head impacts in contact/collision sports. A core clinical feature of TES is cognitive impairment, particularly in memory and executive functions. Cognitive intraindividual variability (IIV) is the extent of variability in neuropsychological test performance (i.

Spatial proteomic differences in chronic traumatic encephalopathy, Alzheimer's disease, and primary age-related tauopathy hippocampi.

Introduction: Alzheimer's disease (AD), primary age-related tauopathy (PART), and chronic traumatic encephalopathy (CTE) all feature hyperphosphorylated tau (p-tau)-immunoreactive neurofibrillary degeneration, but differ in neuroanatomical distribution and progression of neurofibrillary degeneration and amyloid beta (Aβ) deposition.

Methods: We used Nanostring GeoMx Digital Spatial Profiling to compare the expression of 70 proteins in neurofibrillary tangle (NFT)-bearing and non-NFT-bearing neurons in hippocampal CA1, CA2, and CA4 subregions and entorhinal cortex of cases with autopsy-confirmed AD (n = 8), PART (n = 7), and CTE (n = 5).

Results: There were numerous subregion-specific differences related to Aβ processing, autophagy/proteostasis, inflammation, gliosis, oxidative stress, neuronal/synaptic integrity, and p-tau epitopes among these different disorders.

Associations Between Retinal Vascular Occlusions and Dementia.

Background/objectives: Retinal vascular occlusions, such as retinal vein occlusion (RVO) and retinal artery occlusion (RAO), are associated with cognitive impairment, including dementia. Our objective was to examine the odds of dementia among patients with retinal vascular occlusion.

Methods: This cross-sectional study included 474 patients with retinal vascular occlusion and 948 patients without retinal vascular occlusion (comparison group).

Olfactory function is reduced in a subset of former elite American football players with traumatic encephalopathy syndrome.

Former American football players are at risk for developing traumatic encephalopathy syndrome (TES), the clinical disorder associated with neuropathologically diagnosed chronic traumatic encephalopathy (CTE). The objective of this study was to determine whether hyposmia is present in traumatic encephalopathy syndrome. The study included 119 former professional American football players, 60 former college football players, and 58 same-age asymptomatic unexposed men from the DIAGNOSE CTE Research Project.

Obfuscation via pitch-shifting for balancing privacy and diagnostic utility in voice-based cognitive assessment.

Introduction: Digital voice analysis is gaining traction as a tool to differentiate cognitively normal from impaired individuals. However, voice data poses privacy risks due to the potential identification of speakers by automated systems.

Methods: We developed a framework that uses weighted linear interpolation of privacy and utility metrics to balance speaker obfuscation and cognitive integrity in cognitive assessments.

Duration of Ice Hockey Play and Chronic Traumatic Encephalopathy.

Importance: Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive head impacts (RHIs). Prior research suggests a dose-response association between American football play duration and CTE risk and severity, but this association has not been studied for ice hockey.

Objective: To investigate associations of duration of ice hockey play with CTE diagnosis and severity, functional status, and dementia.

Cultural Considerations in Intelligence Test Adaptations: a Critical Review of the WAIS-IV India and Its U.K. and U.S. Counterparts.

Objective: This study critically examined the adaptation and normative processes of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV)India.

Method: WAIS-IV U.K.

SHARD: an improved method for staining and visualizing multiplex immunofluorescence in optically cleared postmortem human brain tissue.

Postmortem human brain tissue is a critical resource for studying neurodegenerative disease, providing critical insights into cellular morphology, pathology, and network connectivity. To improve standard microscopy and enable high-resolution, three-dimensional (3D) images of tissues at the subcellular level, tissue-clearing methods have been developed. These 3D images allow for the analysis of large regions of interest and can be used to study structural and spatial changes that occur during neurodegeneration.