Evaluating memory testing to distinguish dementia severity among White, Black, and Spanish-speaking individuals in the Uniform Data Set (UDS).

INTRODUCTION: Little work has compared the effectiveness of using multiple types of memory tests alone or in combination to distinguish dementia severity in diverse research cohorts including Black individuals and Spanish speakers. Here we evaluate word list and paragraph recall tests to distinguish cognitively normal, mild cognitively impaired, and those with Alzheimer's disease in diverse cohorts. METHODS: Using Uniform Data Set (UDS) and site-specific supplemental data, logistic regression models and receiver operating characteristic-area under the curve were used to compare paragraph recall versus word list in differentiating among Clinical Dementia Rating (CDR) scale level. RESULTS: Results reveal high discriminability for all groups and no difference between either test in distinguishing between CDR levels. Combining tests improved discriminability for the whole group but did not for Black individuals or Spanish speakers. DISCUSSION: Our findings indicate that using multiple memory tests may not improve differentiation between cognitive impairment levels for diverse cohorts. The burden of added testing may be a barrier for maximizing inclusion of under-represented groups in research.

The use of subjective cognitive complaints for detecting mild cognitive impairment in older adults across cultural and linguistic groups: A comparison of the Cognitive Function Instrument to the Montreal Cognitive Assessment.

INTRODUCTION: This pilot study aims to explore the psychometric properties of the Cognitive Function Instrument (CFI) as a measure of subjective cognitive complaints (SCC) and its performance in distinguishing mild cognitive impairment (MCI) from normal control (NC) compared to an objective cognitive screen (Montreal Cognitive Assessment [MoCA]). METHODS: One hundred ninety-four community-dwelling non-demented older adults with racial/ethnic diversity were included. Unidimensionality and internal consistency of the CFI were examined using factor analysis, Cronbach's alpha, and McDonald's omega. Logistic regression models and receiver operating characteristic (ROC) analysis were used to examine the performance of CFI. RESULTS: The CFI demonstrated adequate internal consistency; however, the fit for a unidimensional model was suboptimal. The CFI distinguished MCI from NC alone or in combination with MoCA. ROC analysis showed comparable performance of the CFI and the MoCA. DISCUSSION: Our findings support the use of CFI as a brief and easy-to-use screen to detect MCI in culturally/linguistically diverse older adults. HIGHLIGHT: What is the key scientific question or problem of central interest of the paper? Subjective cognitive complaints (SCCs) are considered the earliest sign of dementia in older adults. However, it is unclear if SCC are equivalent in different cultures. The Cognitive Function Instrument (CFI) is a 14-item measure of SCC. This study provides pilot data suggesting that CFI is sensitive for detecting mild cognitive impairment in a cohort of older adults with racial/ethnic diversity. Comparing performance, CFI demonstrates comparable sensitivity to the Montreal Cognitive Assessment, an objective cognitive screening test. Overall, SCC may provide a non-invasive, easy-to-use method to flag possible cognitive impairment in both research and clinical settings.

Role of cumulative biological risk in mediating socioeconomic disparities in cognitive function in the elderly: a mediation analysis.

OBJECTIVES: To evaluate whether allostatic load (AL), a measure of cumulative biological risk, fully or partially mediates observed socioeconomic status (SES) differences in cognitive function in the elderly. DESIGN: Cross-sectional mediation analysis. SETTING: Community-dwelling US elderly who participated in the National Health and Nutrition Examination Survey (NHANES). PARTICIPANTS: The NHANES uses a complex, multistage, probability sampling design to select a nationally representative sample. Of the 4976 elderly (60 years or older) who were selected, 3234 agreed to participate in the household and medical exam interviews (65% response rate). PRIMARY AND SECONDARY OUTCOME MEASURES: Performance on the Digit Symbol Substitution Test (DSST)-a measure of cognitive function. RESULTS: Relative to participants with the lowest level of education or family income, participants who were college graduates (ß=24.4, 95% CI 22 to 26.8, p<0.0001) or in the highest income quartile (ß=17.3, 95% CI 15.2 to 19.4, p<0.0001) had the highest DSST scores and the least AL burden (ß=-0.72, 95% CI -0.98 to -0.47 and ß=-0.82, 95% CI -1 to -0.57; p<0.0001, respectively). Although, AL was significantly negatively associated with cognitive performance (ß = -1, 95% CI -1.4 to -0.5, p<0.0001), it mediated at most 4.5% of the SES effect on DSST performance. CONCLUSIONS: The findings suggest that AL, as measured by a summary index of parameters for cardiovascular function, metabolism and chronic inflammation, is not a significant mediator of SES-related differences in cognitive function in the elderly. Further efforts are required to elucidate the exact physiological pathways and mechanisms through which SES impacts cognitive function in late life.

Glycemic control, inflammation, and cognitive function in older patients with type 2 diabetes.

OBJECTIVE: Glycated hemoglobin (HbA1c) and C-reactive protein (CRP) have been associated with cognitive impairment independently. However, it is unclear if their combination exacerbates poor cognitive function. We assessed whether long-term glycemic level and glycemic variability modulate the association of systemic inflammation with cognitive function, in a sample of cognitively normal older people with type 2 diabetes. METHODS: A retrospective cohort study of 777 randomly selected participants from ~11,000 patients in the Maccabi Healthcare Services Diabetes Registry, as part of the Israel Diabetes and Cognitive Decline study. Subjects averaged 18 (±9.4) HbA1c measures in the Maccabi Healthcare Services Registry, which were used to calculate long-term glycemic level (HbA1c-mean) and glycemic variability (HbA1c-standard deviation (SD)). Linear regression models assessed the interactions of CRP, a marker of systemic inflammation, with HbA1c-mean and HbA1c-SD on subjects' performance in tests of Memory, Executive Functions, Attention, and Semantic Categorization. RESULTS: Quadratic interactions of CRP with HbA1c-SD approached significance for executive functions and overall cognition. However, after Bonferroni adjustment, none of the interactions of CRP with HbA1c were statistically significant. In partial correlations according to HbA1c-SD tertiles, CRP was weakly correlated in the middle tertile with decreased performance in the domains of semantic categorization (r = -0.166, p = 0.011), executive functions (r = -0.136, p = 0.038), and overall cognition (r = -0.157, p = 0.016). CONCLUSIONS: Glycated hemoglobin does not substantially modulate the association of CRP with cognition in a sample of cognitively normal, community dwelling older people with relatively well-managed type 2 diabetes.

Changes in glycemic control are associated with changes in cognition in non-diabetic elderly.

The aim of the present study was to examine the relationship of changes in long term glucose levels as measured by Hemoglobin A1c (HbA1c) with simultaneous changes in cognition. The sample included in the present analysis consisted of 101 community dwelling non-diabetic elderly subjects participating in ongoing longitudinal studies of cognition. Subjects were included in this study if they were cognitively normal at baseline, had at least one co-temporaneous follow-up assessment of HbA1c and the Mini Mental State Exam (MMSE), and complete data on age, gender, race, and years of education. MMSE decline over time was the main outcome measure. In TOBIT mixed regression models, MMSE was the dependent variable and HbA1c the time-varying covariate. Sociodemographic (age, gender, and education), cardiovascular (hypertension and APOE4 status), and lifestyle (smoking and physical activity) covariates were included in the statistical model. After adjusting for age at follow-up, there was a decrease of 1.37 points in the MMSE (p = 0.0002) per unit increase in HbA1c. This result remained essentially unchanged after adjusting also for gender and education (p = 0.0005), cardiovascular factors (p = 0.0003), and lifestyle (p = 0.0006). Additionally, results remained very similar after excluding subjects with potentially incipient diabetes with HbA1c between 6 and 7. These findings suggest that in non-diabetic non-demented elderly subjects, an increase in HbA1c over time is associated with cognitive decline. Such results may have broad clinical applicability since manipulation of glucose control, even in non-diabetics, may affect cognitive performance, perhaps enabling preventive measures against dementia.