Informing etiological heterogeneity of mild cognitive impairment and risk for progression to dementia with plasma p-tau217.

Background: Mild cognitive impairment (MCI) is a clinical diagnosis representing early symptom changes with preserved functional independence. There are multiple potential etiologies of MCI. While often presumed to be related to Alzheimer's disease (AD), other neurodegenerative and non-neurodegenerative causes are common.

Predictors of Retention in the 1Florida Alzheimer's Disease Research Center (ADRC) Over Two Waves.

Attrition is a significant methodological concern in longitudinal studies. Sample loss can limit generalizability and compromise internal validity. Wave one ( = 346) and wave two follow-ups ( = 196) of the 1Florida ADRC clinical core were examined using a 24-month visit window.

The Association Between Plasma Amyloid-β 42/40 and Percentage of Semantic Intrusion Errors in Mild Cognitive Impairment.

Background: Semantic intrusion errors (SIEs) are both sensitive and specific to PET amyloid-β (Aβ) burden in older adults with amnestic mild cognitive impairment (aMCI).

Objective: Plasma Aβ biomarkers including the Aβ42/40 ratio using mass spectrometry are expected to become increasingly valuable in clinical settings. Plasma biomarkers are more clinically informative if linked to cognitive deficits that are salient to Alzheimer's disease (AD).

Neuroimaging and biofluid biomarkers across race and ethnicity in older adults across the spectrum of cognition.

Neuroimaging and biofluid biomarkers provide a proxy of pathological changes for Alzheimer's disease (AD) and are useful in improving diagnosis and assessing disease progression. However, it is not clear how race/ethnicity and different prevalence of AD risks impact biomarker levels. In this narrative review, we survey studies focusing on comparing biomarker differences between non-Hispanic White American(s) (NHW), African American(s) (AA), Hispanic/Latino American(s) (HLA), and Asian American(s) with normal cognition, mild cognitive impairment, and dementia.

The computerized LASSI-BC Test versus the Standard LASSI-L Paper-and-Pencil Version in Community-Based-Samples.

Proactive Semantic Interference (PSI) and failure to recover from PSI (frPSI), are novel constructs assessed by the LASSI-L. These measures are sensitive to cognitive changes in early Mild Cognitive Impairment (MCI) and preclinical AD determined by A load using PET. The goal of this study was to compare a new computerized version of the LASSI-L (LASSI-Brief Computerized) to the standard paper-and-pencil version of the test.

Plasma p-tau217 concordance with amyloid PET among ethnically diverse older adults.

Introduction: Commercially available plasma p-tau217 biomarker tests are not well studied in ethnically diverse samples.

Methods: We evaluated associations between ALZPath plasma p-tau217 and amyloid-beta positron emission tomography (Aβ-PET) in Hispanic/Latino (88% of Cuban or South American ancestry) and non-Hispanic/Latino older adults. One- and two-cutoff ranges were derived and evaluated to assess agreement with Aβ-PET.

A Novel Computerized Cognitive Test for the Detection of Mild Cognitive Impairment and Its Association with Neurodegeneration in Alzheimer's Disease Prone Brain Regions.

During the prodromal stage of Alzheimer's disease (AD), neurodegenerative changes can be identified by measuring volumetric loss in AD-prone brain regions on MRI. Cognitive assessments that are sensitive enough to measure the early brain-behavior manifestations of AD and that correlate with biomarkers of neurodegeneration are needed to identify and monitor individuals at risk for dementia. Weak sensitivity to early cognitive change has been a major limitation of traditional cognitive assessments.

Diffusion MRI relates to plasma Aβ42/40 in PET negative participants without dementia.

Introduction: Magnetic resonance imaging (MRI) biomarkers are needed for indexing early biological stages of Alzheimer's disease (AD), such as plasma amyloid-β (Aβ42/40) positivity in Aβ positron emission tomography (PET) negative individuals.

Methods: Diffusion free-water (FW) MRI was acquired in individuals with normal cognition (NC) and mild cognitive impairment (MCI) with Aβ plasma-/PET- (NC = 22, MCI = 60), plasma+/PET- (NC = 5, MCI = 20), and plasma+/PET+ (AD dementia = 21) biomarker status. Gray and white matter FW and fractional anisotropy (FAt) were compared cross-sectionally and the relationships between imaging, plasma and PET biomarkers were assessed.

Cross-cultural Diagnostic Validity of the Multilingual Naming Test (MINT) in a Sample of Older Adults.

Objective: We aimed to evaluate the psychometric properties and diagnostic accuracy of the 32-item version of the Multilingual Naming Test (MINT) in participants from 2 ethnic groups (European Americans [EA; n = 106] and Hispanic Americans [HA; n = 175]) with 3 diagnostic groups (cognitively normal [CN], n = 94, mild cognitive impairment [MCI], n = 148, and dementia, n = 39).

Method: An Item Response Theory model was used to evaluate items across ethnicity and language groups (Spanish and English), resulting in a 24-item version. We analyzed the MINT discriminant and predictive validity across diagnostic groups.

Free-water imaging reveals unique brain microstructural deficits in hispanic individuals with Dementia.

Prior evidence suggests that Hispanic and non-Hispanic individuals differ in potential risk factors for the development of dementia. Here we determine whether specific brain regions are associated with cognitive performance for either ethnicity along various stages of Alzheimer's disease. For this cross-sectional study, we examined 108 participants (61 Hispanic vs.

Plasma Alzheimer's biomarkers and brain amyloid in Hispanic and non-Hispanic older adults.

Introduction: Alzheimer's disease studies often lack ethnic diversity.

Methods: We evaluated associations between plasma biomarkers commonly studied in Alzheimer's (p-tau181, GFAP, and NfL), clinical diagnosis (clinically normal, amnestic MCI, amnestic dementia, or non-amnestic MCI/dementia), and Aβ-PET in Hispanic and non-Hispanic older adults. Hispanics were predominantly of Cuban or South American ancestry.

Semantic intrusion errors are associated with plasma Ptau-181 among persons with amnestic mild cognitive impairment who are amyloid positive.

Introduction: Semantic intrusion errors (SI) have distinguished between those with amnestic Mild Cognitive Impairment (aMCI) who are amyloid positive (A+) versus negative (A-) on positron emission tomography (PET).

Method: This study examines the association between SI and plasma - based biomarkers. One hundred and twenty-eight participants received SiMoA derived measures of plasma pTau-181, ratio of two amyloid-β peptide fragments (Aβ42/Aβ40), Neurofilament Light protein (NfL), Glial Fibrillary Acidic Protein (GFAP), ApoE genotyping, and amyloid PET imaging.

Stability in cognitive classification as a function of severity of impairment and ethnicity: A longitudinal analysis.

Objective: The interaction of ethnicity, progression of cognitive impairment, and neuroimaging biomarkers of Alzheimer's Disease remains unclear. We investigated the stability in cognitive status classification (cognitively normal [CN] and mild cognitive impairment [MCI]) of 209 participants (124 Hispanics/Latinos and 85 European Americans).

Methods: Biomarkers (structural MRI and amyloid PET scans) were compared between Hispanic/Latino and European American individuals who presented a change in cognitive diagnosis during the second or third follow-up and those who remained stable over time.

Early Amnestic Mild Cognitive Impairment Is Associated with Reduced Total Cerebral Blood Flow with no Brain Tissue Loss.

Background: Lower cerebral blood flow (CBF) and excessive brain atrophy are linked to Alzheimer's disease (AD). It is still undetermined whether reduced CBF precedes or follows brain tissue loss.

Objective: We compared total CBF (tCBF), global cerebral perfusion (GCP), and volumes of AD-prone regions between cognitively normal (CN) and early amnestic mild cognitive impairment (aMCI) and tested their associations with cognitive performance to assess their predictive value for differentiation between CN and early aMCI.

A review of novel Cognitive Challenge Tests for the assessment of preclinical Alzheimer's disease.

Objectives: There is currently a lack of consensus among neuropsychologists about which cognitive assessment paradigms hold the most promise in identifying subtle cognitive deficits in preclinical Alzheimer's Disease (AD) and which are most useful for monitoring risk of cognitive deterioration. Many widely used instruments are older versions of tests originally developed for the assessment of dementia or traumatic brain injury. Current efforts to digitize these measures provides more uniform and remote assessment, which is an advancement, but does not reflect significant changes in paradigmatic underpinnings or recent advances in cognitive neuroscience.

Associations Between Country where Education is Obtained and Cognitive Functioning Among South American and Caribbean Older Adults Living in the U.S.

The increasing prevalence of AD among Hispanics calls for a need for examining factors that affect cognitive functioning and risk of AD among Hispanic older adults. The current study examined cognitive functioning among older Hispanic adults living in the U.S.

Neuropsychological, Metabolic, and Connectivity Underpinnings of Semantic Interference Deficits Using the LASSI-L.

Background: LASSI-L is a novel neuropsychological test specifically designed for the early diagnosis of Alzheimer's disease (AD) based on semantic interference.

Objective: To examine the cognitive and neural underpinnings of the failure to recover from proactive semantic and retroactive semantic interference.

Methods: One hundred and fifty-five patients consulting for memory loss were included.

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline.

Background: With our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.

Persistent Failure to Recover from Proactive Semantic Interference on the Cognitive Stress Test Differentiates Between Amnestic Mild Cognitive Impairment, Pre-Mild Cognitive Impairment, and Cognitively Unimpaired Older Adults.

Background: Susceptibility to proactive semantic interference (PSI) and the inability to ameliorate these difficulties with one additional learning trial have repeatedly been implicated as early features of incipient Alzheimer's disease (AD). Unfortunately, persistent failure to recover from PSI (frPSI) after repeated learning trials, are not captured by existing memory measures, or been examined in pre-mild cognitive impairment (PreMCI).

Objective: A novel Cognitive Stress Test (CST) was employed to measure the impact of PSI, initial failure to recover from PSI and persistent effects of PSI, despite multiple learning trials of the new to-be-remembered material (pfrPSI).

Associations Between Vascular Risk Factors and Perivascular Spaces in Adults with Intact Cognition, Mild Cognitive Impairment, and Dementia.

Background: Perivascular spaces (PVS) are fluid-filled compartments surrounding small intracerebral vessels that transport fluid and clear waste.

Objective: We examined associations between PVS count, vascular and neurodegenerative risk factors, and cognitive status among the predominantly Hispanic participants of the FL-VIP Study of Alzheimer's Disease Risk.

Methods: Using brain MRI (n = 228), we counted PVS in single axial image through the basal ganglia (BG) and centrum semiovale (CSO).

The association of depression and apathy with Alzheimer's disease biomarkers in a cross-cultural sample.

Cross-cultural differences in the association between neuropsychiatric symptoms and Alzheimer's disease (AD) biomarkers are not well understood. This study aimed to (1) compare depressive symptoms and frequency of reported apathy across diagnostic groups of participants with normal cognition (CN), mild cognitive impairment (MCI), and dementia, as well as ethnic groups of Hispanic Americans (HA) and European Americans (EA); (2) evaluate the relationship between depression and apathy with Aβ deposition and brain atrophy. Statistical analyses included ANCOVAs, chi-squared, nonparametric tests, correlations, and logistic regressions.

A Tensorized Multitask Deep Learning Network for Progression Prediction of Alzheimer's Disease.

With the advances in machine learning for the diagnosis of Alzheimer's disease (AD), most studies have focused on either identifying the subject's status through classification algorithms or on predicting their cognitive scores through regression methods, neglecting the potential association between these two tasks. Motivated by the need to enhance the prospects for early diagnosis along with the ability to predict future disease states, this study proposes a deep neural network based on modality fusion, kernelization, and tensorization that perform multiclass classification and longitudinal regression simultaneously within a unified multitask framework. This relationship between multiclass classification and longitudinal regression is found to boost the efficacy of the final model in dealing with both tasks.

Associations Between Cognitive Functioning and Mortality in a Population-Based Sample of Older United States Adults: Differences by Sex and Education.

To determine whether cognition is associated with mortality among older US adults. We studied 5,989 National Health and Nutrition Examination Survey participants age 60+ in years 1999-2014 with mortality follow-up through 2015. Cognitive function was measured in one standard deviation decrements using the Digit Symbol Substitution Test (DSST), Animal Fluency (AnFl), and two Consortium to Establish a Registry for Alzheimer's Disease (CERAD) tests.