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.

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.

Sex significantly predicts medial temporal volume when controlling for the influence of ApoE4 biomarker and demographic variables: A cross-ethnic comparison.

Objective: To explore the relationship between age, education, sex, and ApoE4 (+) status to brain volume among a cohort with amnestic mild cognitive impairment (aMCI).

Method: One hundred and twenty-three participants were stratified into Hispanic ( = 75) and White non-Hispanic (WNH, = 48). Multiple linear regression analyses were conducted with age, education, sex, and ApoE4 status as predictor variables and left and right combined MRI volumes of the hippocampus, parahippocampus, and entorhinal cortex as dependent variables.

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.

Transcript levels in plasma contribute substantial predictive value as potential Alzheimer's disease biomarkers in African Americans.

Background: African Americans (AA) remain underrepresented in Alzheimer's disease (AD) research, despite the prevalence of AD being double in AA compared to non-Hispanic whites. To address this disparity, our group has established the Florida Consortium for African American Alzheimer's Disease Studies (FCADS), focusing on the identification of genetic risk factors and novel plasma biomarkers.

Method: Utilizing FCADS whole exome sequence (WES) and plasma RNA samples from AD cases (n=151) and cognitively unimpaired (CU) elderly controls (n=269), we have performed differential gene expression (DGE) and expression quantitative trait locus (eQTL) analyses on 50 transcripts measured with a custom nanoString® panel.

Changes in LASSI-L performance over time among older adults with amnestic MCI and amyloid positivity: A preliminary study.

There is a pressing need to develop measures that are sensitive to the earliest subtle cognitive changes of Alzheimer's disease (AD) to improve early detection and track disease progression. The Loewenstein-Acevedo Scales of Semantic Interference (LASSI-L) has been shown to successfully discriminate between cognitively unimpaired (CU) older adults and those with amnestic mild cognitive impairment (MCI) and to correlate with total and regional brain amyloid load. The present study investigated how the LASSI-L scores change over time among three distinct diagnostic groups.

The relationship of semantic intrusions to different etiological subtypes of MCI and cognitively healthy older adults.

Introduction: There is increasing evidence that susceptibility to proactive semantic interference (PSI) and the failure to recover from PSI (frPSI) as evidenced by intrusion errors may be early cognitive markers of both preclinical and prodromal Alzheimer's disease (AD).

Methods: One hundred forty-five participants were administered extensive clinical and neuropsychological evaluations including the Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L), a sensitive cognitive stress test measuring PSI and frPSI. Participants also underwent structural magnetic resonance imaging (MRI) and amyloid positron emission tomography/computed tomography (PET/CT) imaging.

The effect of acculturation on cognitive performance among older Hispanics in the United States.

The effect of acculturation on cognition was examined among 142 older Hispanics: cognitively normal [CN;  = 70], Mild Cognitive Impairment, amnestic [aMCI;  = 27], and Dementia [D;  = 45]. Acculturation levels (high vs. low) were determined using the Short Acculturation Scale for Hispanics (SASH).

A cognitive stress test for prodromal Alzheimer's disease: Multiethnic generalizability.

Introduction: Culturally fair cognitive assessments sensitive to detecting changes associated with prodromal Alzheimer's disease are needed.

Methods: Performance of Hispanic and non-Hispanic older adults on the Loewenstein-Acevedo Scale of Semantic Interference and Learning (LASSI-L) was examined in persons with amnestic mild cognitive impairment (aMCI) or normal cognition. The association between a novel cognitive marker, the failure to recover from proactive semantic interference (frPSI), and cortical thinning was explored.

Ethnoracial differences in Alzheimer's disease from the FLorida Autopsied Multi-Ethnic (FLAME) cohort.

Introduction: Our primary goal was to examine demographic and clinicopathologic differences across an ethnoracially diverse autopsy-confirmed cohort of Alzheimer's disease cases.

Methods: A retrospective study was conducted in the Florida Autopsied Multi-Ethnic cohort on 1625 Alzheimer's disease cases, including decedents who self-reported as Hispanic/Latino (n = 67), black/African American (n = 19), and white/European American (n = 1539).

Results: Hispanic decedents had a higher frequency of family history of cognitive impairment (58%), an earlier age at onset (median age of 70 years), longer disease duration (median of 12 years), and lower MMSE proximal to death (median of 4 points) compared with the other ethnoracial groups.

Utilizing semantic intrusions to identify amyloid positivity in mild cognitive impairment.

Objective: Semantic intrusion (SI) errors may highlight specific breakdowns in memory associated with preclinical Alzheimer disease (AD); however, there have been no investigations to determine whether SI errors occur with greater frequency in persons with amnestic mild cognitive impairment (aMCI) confirmed as amyloid positive (Amy+) vs those who have clinical symptoms of aMCI-AD with negative amyloid scans (suspected non-AD pathology [SNAP]) or persons who are diagnosed with other brain disorders affecting cognition.

Methods: Eighty-eight participants with aMCI underwent brain amyloid PET and MRI scans and were classified as early AD (Amy+), SNAP (Amy-), or other neurological/psychiatric diagnosis (Amy-). We focused on SI on the Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L) targeting proactive semantic interference (PSI; old semantic learning interferes with new semantic learning), failure to recover from PSI after an additional learning trial (frPSI), and retroactive semantic interference (new semantic learning interferes with memory for old semantic learning).

Semantic Intrusions and Failure to Recover From Semantic Interference in Mild Cognitive Impairment: Relationship to Amyloid and Cortical Thickness.

Background: Accumulating evidence indicates that the failure to recover from the effects of proactive semantic interference [frPSI] represents an early cognitive manifestation of preclinical Alzheimer's disease. A limitation of this novel paradigm has been a singular focus on the number of targets correctly recalled, without examining co-occurring semantic intrusions [SI] that may highlight specific breakdowns in memory.

Objectives: We focused on SI and their relationship to amyloid load and regional cortical thickness among persons with amnestic mild cognitive impairment (aMCI).

Relationship between Cognitive Performance and Measures of Neurodegeneration among Hispanic and White Non-Hispanic Individuals with Normal Cognition, Mild Cognitive Impairment, and Dementia.

Objectives: The aim of this study was to determine the presence and severity of potential cultural and language bias in widely used cognitive and other assessment instruments, using structural MRI measures of neurodegeneration as biomarkers of disease stage and severity.

Methods: Hispanic (n=75) and White non-Hispanic (WNH) (n=90) subjects were classified as cognitively normal (CN), amnestic mild cognitive impairment (aMCI) and mild dementia. Performance on the culture-fair and educationally fair Fuld Object Memory Evaluation (FOME) and Clinical Dementia Rating Scale (CDR) between Hispanics and WNHs was equivalent, in each diagnostic group.

African American exome sequencing identifies potential risk variants at Alzheimer disease loci.

Objective: In African Americans, we sought to systematically identify coding Alzheimer disease (AD) risk variants at the previously reported AD genome-wide association study (GWAS) loci genes.

Methods: We identified coding variants within genes at the 20 published AD GWAS loci by whole-exome sequencing of 238 African American participants, validated these in 300 additional participants, and tested their association with AD risk in the combined cohort of 538 and with memory endophenotypes in 319 participants.

Results: Two missense variants (rs3764647 and rs3752239) demonstrated significant association with AD risk.

The presenilin 1 p.Gly206Ala mutation is a frequent cause of early-onset Alzheimer's disease in Hispanics in Florida.

Mutations in the gene encoding the presenilin-1 protein (PSEN1) were first discovered to cause Alzheimer's disease (AD) 20 years ago. Since then more than 200 different pathogenic mutations have been reported, including a p.Gly206Ala founder mutation in the Hispanic population.

Cognitive and structural magnetic resonance imaging features of Lewy body dementia and Alzheimer's disease.

Objective: To assess medial temporal atrophy (MTA) and atrophy adjacent to the third ventricle (Peri-IIIVent) on brain magnetic resonance images as biomarkers for the diagnosis of Alzheimer's disease (AD) and Lewy body dementia (LBD), and to assess the relationship between biomarkers and clinical and functional measures.

Methods: Subjects diagnosed with no cognitive impairment (n = 30), AD (n = 30), or LBD (n = 31) were evaluated with the Mini-Mental State Examination, Multiple Delayed Recall Test, Category Fluency Test, Clinical Dementia Rating Sum of Boxes score, Functional Assessment Questionnaire, and the Unified Parkinson's Disease Rating Scale. A validated visual rating system was used to rate MTA, and volumetric studies were performed to measure total intracranial and hippocampal volumes.

Diagnosis and staging of mild cognitive impairment, using a modification of the clinical dementia rating scale: the mCDR.

Objective: To examine the reliability and validity of the mCDR, a modified version of the clinical dementia rating (CDR) scale.

Methods: The mCDR is an informant-based, technician-administered, structured interview with multiple choice responses, which does not include objective cognitive testing. Subjects (n = 556) with no cognitive impairment (NCI), amnestic mild cognitive impairment (aMCI), and dementia were assessed with mCDR, CDR, and neuropsychological evaluation, while medial temporal atrophy (MTA) was measured on MRI scans.

A clinical perspective of mild cognitive impairment: what radiologists should know.

Mild cognitive impairment (MCI), a major risk factor for dementia, has an amnestic subtype that has a high probability of progressing to Alzheimer's disease. The rate of progression may be predicted by the severity of memory impairment at baseline, the severity of hippocampal atrophy, and, possibly, the presence of an epsilon4 allele of the apolipoprotein E gene. MCI can be diagnosed using purely clinical or a combination of clinical and neuropsychologic criteria.