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The Controlled Oral Word Association (COWA) test is used to assess phonemic fluency and executive function. Formal validation of test scores is important for accurate cognitive evaluation. However, there is a dearth of psychometric validation among American Indian adults. Given high burden of dementia risk and key contextual factors associated with cognitive assessments, this represents a critical oversight. In a large, longitudinal population-based cohort study of adult American Indians, we examined several validity inferences for COWA, including scoring, generalization, and extrapolation inferences, by investigation of factor structure, internal consistency, test–retest reliability, and differential test functioning. We found adequate unidimensional model fit, with high factor loadings. Internal consistency reliability and test–retest reliability were 0.88 and 0.77, respectively, for the full group. COWA scores were lowest among the oldest, lowest education, bilingual speakers; group effects for sex and bilingual status were small; age effect was medium; and education effect was largest. However, Wide Range Achievement Test (WRAT) score effect was stronger than education effect, suggesting better contextualization may be needed. These results support interpretation of total COWA score, including across sex, age, or language use strata. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Identification of Alzheimer's disease (AD) needs inexpensive, noninvasive biomarkers, with validation in all populations. METHODS: We collected plasma markers in older American Indian individuals: phosphorylated‐tau181 (pTau181); amyloid‐beta (Aβ) 40,42; glial fibrillary acidic protein (GFAP); and neurofilament light chain (NfL). Plasma markers were analyzed for discriminant properties with cognitive status and etiology using receiver operating characteristic (ROC) analysis. RESULTS: PTau181, GFAP, NfL plasma values were significantly associated with cognition, but Aβ were not. Discriminant performance was moderate for individual markers, with pTau181, GFAP, NfL performing best, but an empirically selected panel of markers (age, sex, education, pTau181, GFAP, NfL, Aβ4240 ratio) had excellent discriminant performance (AUC > 0.8). DISCUSSION: In American Indian individuals, pTau181 and Aβ values suggested more common pathology than in majority populations. Aβ was less informative than in other populations; however, all four markers were needed for a best‐performing dementia diagnostic model. These data validate utility of AD plasma markers, while suggesting population‐specific diagnostic characteristics. [ABSTRACT FROM AUTHOR]

Objectives. Spoken bilingualism may be associated with cognitive reserve. Mastering a complicated written language may be associated with additional reserve. We sought to determine if midlife use of spoken and written Japanese was associated with lower rates of late life cognitive decline. Methods. Participants were second-generation Japanese-American men from the Hawaiian island of Oahu, born 1900-1919, free of dementia in 1991, and categorized based on midlife self-reported use of spoken and written Japanese (total n included in primary analysis = 2,520). Cognitive functioning was measured with the Cognitive Abilities Screening Instrument scored using item response theory. We used mixed effects models, controlling for age, income, education, smoking status, apolipoprotein E e4 alleles, and number of study visits. Results. Rates of cognitive decline were not related to use of spoken or written Japanese. This finding was consistent across numerous sensitivity analyses. Discussion. We did not find evidence to support the hypothesis that multilingualism is associated with cognitive reserve. Key Words: Aging--Bilingualism--Cognitive decline--Cognitive reserve--Japanese language--Psychometrics. doi: 10.1093/geronb/gbq046.

The present study examined the relationships among statin use, APOE genotype, and insulin resistance as measured by the homeostasis model assessment of insulin resistance (HOMA-IR) in healthy older adults. APOE ℇ4- (i.e., not having an ℇ4 allele) statin users had higher HOMA-IR values compared with ℇ4+/statin users (p=0.0169), and with non-users who were ℇ4- (p=0.0003) or ℇ4+ (p=0.0006). These results suggest that statin use may modulate insulin levels for individuals without an APOE ℇ4 allele. [ABSTRACT FROM AUTHOR]

Background: The Cognitive Abilities Screening Instrument (CASI) was designed for use in cross-cultural studies of Japanese and Japanese-American elderly in Japan and the U.S.A. The measurement equivalence in Japanese and English had not been confirmed in prior studies. Methods:We analyzed the 40 CASI items for differential item functioning (DIF) related to test language, as well as self-reported proficiency with written Japanese, age, and educational attainment in two large epidemiologic studies of Japanese-American elderly: the Kame Project (n=1708) and the Honolulu-Asia Aging Study (HAAS; n=3148). DIF was present if the demographic groups differed in the probability of success on an item, after controlling for their underlying cognitive functioning ability. Results: While seven CASI items had DIF related to language of testing in Kame (registration of one item; recall of one item; similes; judgment; repeating a phrase; reading and performing a command; and following a three-step instruction), the impact of DIF on participants' scores was minimal. Mean scores for Japanese and English speakers in Kame changed by < 0.1 SD after accounting for DIF related to test language. In HAAS, insufficient numbers of participants were tested in Japanese to assess DIF related to test language. In both studies, DIF related to written Japanese proficiency, age, and educational attainment had minimal impact. Conclusions: To the extent that DIF could be assessed, the CASI appeared to meet the goal of measuring cognitive function equivalently in Japanese and English. Stratified data collection would be needed to confirm this conclusion. DIF assessment should be used in other studies with multiple language groups to confirm that measures function equivalently or, if not, form scores that account for DIF. [ABSTRACT FROM AUTHOR]

Standardized neuropsychological instruments are used to evaluate cognitive impairment, but few have been psychometrically evaluated in American Indians. We collected Montreal Cognitive Assessment (MoCA) in 403 American Indians 70 to 95 years, as well as age, sex, education, bilingual status, depression symptoms, and other neuropsychological instruments. We evaluated inferences of psychometric validity, including scoring inference using confirmatory factor analysis and structural equation modeling, generalizability inference using reliability coefficient, and extrapolation inference by examining performance across different contexts and substrata. The unidimensional (total score) model had good fit criteria. Internal consistency reliability was high. MoCA scores were positively associated with crystallized cognition (ρ = 0.48, p < .001) and inversely with depression symptoms (ρ = −0.27, p < .001). Significant differences were found by education (d = 0.79, p < .05) depression (d = 0.484, p < .05), and adjudicated cognitive status (p = .0001) strata; however, MoCA was not sensitive or specific in discriminating cognitive impairment from normal cognition (area under the curve <0.5). MoCA scores had psychometric validity in older American Indians, but education and depression are important contextual features for score interpretability. Future research should evaluate cultural or community-specific adaptations, to improve test discriminability in this underserved population. [ABSTRACT FROM AUTHOR]

Objective: Assessment of cognition in American Indians poses challenges, including barriers to healthcare, unvalidated clinical standards, and confounding social determinants of health. Alternative strategies for case identification include algorithmic methods, which can outperform clinical judgment in some circumstances., Method: Algorithmic methods can be maximized using single-domain tests with multiple-serial trial tasks, such as the California Verbal Learning Test II-Short Form (CVLT-SF). We collected CVLT-SF and detailed clinical data, including dementia gold standard by consensus adjudication, in 818 American Indians aged 65-95 in 2010-2013 and repeated in 403 returning participants in 2017-2019 (mean follow-up 6.7 years, range: 4-9). Our algorithm categorized CVLT-SF scores into four memory deficit categories: none, encoding, storage, and retrieval., Results: At Visit 1, 75.4% had no memory deficit, 15.6% encoding deficit, 3.5% storage deficit, and 5.5% retrieval deficit. At Visit 2, comparable percentages were 68.7%, 10.6%, 6.5%, and 14.2% (respectively). The majority with any deficit at Visit 1-especially encoding-were lost to follow-up by Visit 2. Most with deficits at Visit 2 were newly categorized from those previously intact. The performance of our memory algorithm, compared with adjudication for dementia, was moderately good: correct classification 69%, sensitivity 51%, and specificity 91%., Conclusions: These descriptive findings encompass a novel contribution in defining memory impairment among American Indians from a single cognitive test. However, more work is needed to improve the sensitivity of this algorithm and maximize its utility for case identification over conventional methods. Altogether, these data provide an important step toward better cognitive characterization and dementia care for an understudied, underserved population. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Introduction: Identification of Alzheimer's disease (AD) needs inexpensive, noninvasive biomarkers, with validation in all populations., Methods: We collected plasma markers in older American Indian individuals: phosphorylated-tau181 (pTau181); amyloid-beta (Aβ) 40,42; glial fibrillary acidic protein (GFAP); and neurofilament light chain (NfL). Plasma markers were analyzed for discriminant properties with cognitive status and etiology using receiver operating characteristic (ROC) analysis., Results: PTau181, GFAP, NfL plasma values were significantly associated with cognition, but Aβ were not. Discriminant performance was moderate for individual markers, with pTau181, GFAP, NfL performing best, but an empirically selected panel of markers (age, sex, education, pTau181, GFAP, NfL, Aβ4240 ratio) had excellent discriminant performance (AUC > 0.8)., Discussion: In American Indian individuals, pTau181 and Aβ values suggested more common pathology than in majority populations. Aβ was less informative than in other populations; however, all four markers were needed for a best-performing dementia diagnostic model. These data validate utility of AD plasma markers, while suggesting population-specific diagnostic characteristics., (© 2024 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

The present study examined the relationships among statin use, APOE genotype, and insulin resistance as measured by the homeostasis model assessment of insulin resistance (HOMA-IR) in healthy older adults. APOE epsilon4- (i.e., not having an epsilon4 allele) statin users had higher HOMA-IR values compared with epsilon4+/statin users (p=0.0169), and with non-users who were epsilon4- (p=0.0003) or epsilon4+ (p=0.0006). These results suggest that statin use may modulate insulin levels for individuals without an APOE epsilon4 allele.