2 Neurocognition and Functional Status Among Ethnoculturally Diverse Older Adults: Support for the External Validity of the ADAS-Cog

Abstract

Objective:

Alzheimer’s Disease (AD) and dementia present major and escalating public health concerns for the U.S., especially among ethnoculturally diverse (e.g., Latinx, non-Latinx Black [NLB]) populations who represent an increasing percentage of the older adult population in the US and bear greater AD burden compared to non-Latinx Whites (NLWs). Notably, neurocognition and functional status are highly correlated in those with AD. However, little has been done to understand these associations and validate functional measures across geographically diverse, multiethnic samples. The aims of this study were to characterize the neurocognition and functional status of a large, multiethnic sample and subsequently examine any associations between neurocognition and functional status among Latinx, NLB, and NLW older adults.

Participants and Methods:

This cross-sectional, retrospective study utilized archival data drawn from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). ADNI is a national, longitudinal, multi-site, observational study aiming to measure the progression of AD (see https://adni-info.org). Study measures included the: 1) Alzheimer’s Disease Assessment Scale Cognitive subscale (ADAS-cog; 13-items), a global neurocognitive battery evaluating neurocognition in people with AD; 2) Functional Activities Questionnaire (FAQ; 10-item questionnaire) to assess functional status; 3) Geriatric Depression Scale (GDS; 15-item questionnaire) for depression; and 4) American National Adult Reading Test (ANART; 50-word test) for reading level. The sample included 1537 older adults who completed baseline visits for the ADNI study, 1333 of whom were NLW, 123 NLB, and 81 Latinx. The average age of the sample was 73 years, average 16 years of education, and 53% male. Compared to the NLW group, the NLB and Latinx groups were significantly younger and had a higher percentage of female participants. Compared to NLW and Latinx groups, the NLB group also had significantly fewer years of education and lower reading scores. Potential confounds (i.e., demographic variables, depression) were identified a priori based on the literature and subsequently analyzed for inclusion as covariates in the primary analyses. Analyses revealed variables were non-normally distributed, therefore Independent Samples Kruskal-Wallis tests and Spearman’s Correlations were computed to examine differences and correlations between ethnocultural groups.

Results:

After controlling for age and education, Latinx and NLB groups had significantly higher ADAS-cog and FAQ scores than the NLW group (Hs = 9.50-21.53, ps < .05). Spearman’s partial correlations controlling for age, education, gender, and depression revealed that higher ADAS-cog scores were associated with higher FAQ scores within Latinx (p=.49, p<.001), NLB (p=.66, p<.001), and NLW (p=.60, p<.001) groups.

Conclusions:

Findings indicate that neurocognition is positively associated with functional status and support the ecological and external validity of the ADAS-cog and FAQ for use with NLB and Latinx older adults, in addition to previously established work with more homogenous samples. Study strengths include the overall sample size, geographic diversity, and standardization of research approaches. Study limitations include high education level and low comorbidity rates present in the sample, limiting the generalizability of the results, in addition to the unbalanced ethnocultural groups, further emphasizing the need for increased inclusion efforts of ethnoculturally diverse older adults into brain health research studies.