Intraindividual Cognitive Variability and Magnetic Resonance Imaging in Aging American Indians: Data from the Strong Heart Study

Abstract

Background: American Indians have high prevalence of risk factors for Alzheimer’s disease and related dementias (ADRD) compared to the general population, yet dementia onset and frequency in this population are understudied. Intraindividual cognitive variability (IICV), a measure of variability in neuropsychological test performance within a person at a single timepoint, may be a novel, noninvasive biomarker of neurodegeneration and early dementia. Objective: To characterize the cross-sectional associations between IICV and hippocampal, total brain volume, and white matter disease measured by magnetic resonance imaging (MRI) among older American Indians. Methods: IICV measures for memory, executive function, and processing speed, and multidomain cognition were calculated for 746 American Indians (aged 64–95) who underwent MRI. Regression models were used to examine the associations of IICV score with hippocampal volume, total brain volume, and graded white matter disease, adjusting for age, sex, education, body mass index, intracranial volume, diabetes, stroke, hypertension, hypercholesterolemia, alcohol use, and smoking. Results: Higher memory IICV measure was associated with lower hippocampal volume (Beta = –0.076; 95% CI –0.499, –0.023; p = 0.031). After adjustment for Bonferroni or IICV mean scores in the same tests, the associations were no longer significant. No IICV measures were associated with white matter disease or total brain volume. Conclusion: These findings suggest that the IICV measures used in this research cannot be robustly associated with cross-sectional neuroimaging features; nonetheless, the results encourage future studies investigating the associations between IICV and other brain regions, as well as its utility in the prediction of neurodegeneration and dementia in American Indians.

Mid-life sleep is associated with cognitive performance later in life in aging American Indians: data from the Strong Heart Study

“…Limitations of the study include a modest sample size and potential bias in our sample. Specifically, the mean 3MSE score for our sample was higher than the mean for the entire CDCAI cohort (Mascarenhas Fonseca et al, 2023), suggesting that there may have been some selection bias, with underrepresentation of individuals with more pronounced cognitive impairment in our sample. Furthermore, we do not have data on whether participants sought sleep treatment during the interval between studies, or regarding reasons for non-participation in the CDCAI study.…”

Intraindividual Variability Differentiated Older Adults with Physical Frailty and the Role of Education in the Maintenance of Cognitive Intraindividual Variability

“…(3) (20). Finally, the square root of the sum of variability in the seven components of MoCA was calculated by Eqs (4) to derive the amount of dispersion across the seven components of MoCA (36). …”

“…The copyright holder for this preprint this version posted May 16, 2024. ; https://doi.org/10.1101/2024.05. 16.24307475 doi: medRxiv preprint components of MoCA (36).…”