Dataset Information

Exportation and Validation of Latent Constructs for Dementia Case Finding in a Mexican American Population-based Cohort.

ABSTRACT:

Background

The latent variable "?" has been validated as a dementia phenotype. ? can be extracted from Spearman's general intelligence factor "g" in any data set that contains measures of cognition and instrumental activities of daily living (IADL). We used ? composites ("d-scores") to estimate the prevalence of dementia in the Hispanic Established Population for Epidemiological Studies in the Elderly (H-EPESE).

Method

? was constructed from Mini-Mental State Examination, a clock-drawing task (CLOX), and IADL. ?'s H-EPESE factor weights were validated in the well-characterized Texas Alzheimer's Research and Care Consortium (TARCC). Optimal thresholds for the discrimination between "Alzheimer's disease" (AD) versus normal controls (NCs) were determined by receiver operating characteristic curve. Those thresholds were used to estimate the prevalence of dementia in H-EPESE.

Results

Each ? homolog fits its source's data well. d-scores were strongly associated with Clinical Dementia Rating scale Sum of Boxes (r = .74-.85, all p < .001], and accurately distinguished AD cases from NCs, in both Mexican Americans (MAs) and non-Hispanic Whites (NHWs) [c = 0.94-0.96]. The TARCC MA threshold estimated the prevalence of dementia at 21.4% in H-EPESE. The NHW threshold estimated the prevalence of dementia at 21.0%.

Conclusions

It is possible to export ? composites from populations to well-characterized cohorts for validation.

SUBMITTER: Royall DR

PROVIDER: S-EPMC5927021 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Exportation and Validation of Latent Constructs for Dementia Case Finding in a Mexican American Population-based Cohort.

Royall Donald R DR Palmer Raymond F RF Markides Kyriakos S KS

The journals of gerontology. Series B, Psychological sciences and social sciences 20171001 6

<h4>Background</h4>The latent variable "δ" has been validated as a dementia phenotype. δ can be extracted from Spearman's general intelligence factor "g" in any data set that contains measures of cognition and instrumental activities of daily living (IADL). We used δ composites ("d-scores") to estimate the prevalence of dementia in the Hispanic Established Population for Epidemiological Studies in the Elderly (H-EPESE).<h4>Method</h4>δ was constructed from Mini-Mental State Examination, a clock- ...[more]

PMID: 26968639

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Project description:Currently less than half of the estimated number of people with dementia in England receive a formal diagnosis of dementia or have contact with specialist dementia services. Case finding focused on high risk groups may be an effective way to identify the undiagnosed. This joint Surrey Downs Clinical Commissioning Group and Surrey and Borders NHS Foundation Trust quality improvement project aimed to increase the rate of dementia diagnosis across Surrey Downs using specialist link nurses (SLNs). Thirty three GP surgeries covering the entire Surrey Downs area took part in the project. Individuals at high risk of developing dementia were identified from GP electronic disease registers, and were offered screening at their GP practices by SLNs, using a combination of mini cognitive test (Mini-Cog) and functional assessment questionnaire (FAQ). Suitable individuals who screened positive were seen by their GP and where appropriate referred to secondary care services for further evaluation. Based on the presence of risk factors, 6657 (11.9%) people were identified from a total population of 55 845 over 65s, and 1980 (29.7%) completed the screening assessment. Three hundred and fifty eight (18.1%) individuals screened positive and were referred to their GP, who referred 205 (57.2%) of them to the memory services for further assessment. Of those referred, 164 (80%) had a comprehensive specialist assessment. Forty one (20%) declined further assessment, and their GPs were informed. The mean age of the cohort who completed the comprehensive assessment was 82.3 years (SD=4.26), and were predominantly white and male. Fifty four (32.9%) had mild cognitive disorder (MCD), and 101 (61.6%) patients were diagnosed with dementia. The most common dementia was mixed type (43; 42.6%), followed by Alzheimer's dementia (32; 31.7%). The most common risk factor among patients with cognitive impairment (MCD or dementia) was hypertension (69; 44.5 %), followed by ischemic heart disease (64, 41.3%). Nurse led case finding for cognitive impairment in a high risk population identifies people with dementia who are not yet formally diagnosed. The combined use of brief instruments to assess cognitive functioning and functional capabilities is helpful in identifying individuals with possible dementia.

Project description:Objectives:Brief cognitive tests are recommended in clinical services outside of specialized memory clinics as case-finding tools to reduce the diagnostic gap of dementia. Although the Montreal Cognitive Assessment (MoCA) is among the most widely used brief tests in specialized memory clinics, its length precludes routine use in nonspecialty clinics. This study investigated whether a small subset of MoCA would suffice to match the performance of the full MoCA in detecting dementia and, hence, be useful in nonspecialty clinics.Design:Cross-sectional test research.Setting:Alzheimer's Disease Centers across the United States.Participants:Participants age ?65 years (n = 8773).Measures:Participants completed MoCA and were evaluated for dementia. The study sample was split into 2: the derivation sample (n = 4386) was used to develop a short variant of MoCA that best distinguish dementia (using the best-subset-approach with 10-fold cross-validation), while the validation sample (n = 4387) verified its actual performance using area under the receiver operating characteristic-curve (AUC).Results:A 4-item cognitive test was identified, comprising Clock-drawing, Tap-at-letter-A, Orientation, and Delayed-recall. It demonstrated excellent performance in distinguishing dementia from nondementia (AUC 94.2%) and was comparable to that of MoCA (AUC 93.8%), even across education subgroups. It explained 85.9% of the variability in MoCA and had scores that could be mapped to MoCA with reasonable precision. At the optimal cut-off score of <10, it demonstrated 87.9% sensitivity and 87.6% specificity in detecting dementia.Conclusions and implications:Using rigorous methods, this study developed a brief cognitive test that is free of charge, takes <5 minutes to complete, covers the key cognitive domains, and has standardized instructions to allow its administration even by nonphysicians. This brief test is well suited as a case-finding tool in nonspecialty clinics (such as in primary care and geriatric clinics) and may improve care-integration with specialized memory clinics that utilize MoCA.

Dataset Information

Exportation and Validation of Latent Constructs for Dementia Case Finding in a Mexican American Population-based Cohort.

Background

Method

Results

Conclusions

Publications

Exportation and Validation of Latent Constructs for Dementia Case Finding in a Mexican American Population-based Cohort.

Similar Datasets

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