Cognitive Intraindividual Variability Research Articles

Plasma Aβ42/40 and cognitive variability are associated with cognitive function in Black Americans: Findings from the AA-FAIM cohort.

It is critical to develop more inclusive Alzheimer's disease (AD) research protocols to ensure that historically excluded groups are included in preclinical research and have access to timely diagnosis and treatment. If validated in racialized groups, plasma AD biomarkers and measures of subtle cognitive dysfunction could provide avenues to expand diversity in preclinical AD research. We sought to evaluate the utility of two easily obtained, low-burden disease markers, plasma amyloid beta (Aβ)42/40, and intra-individual cognitive variability (IICV), to predict concurrent and longitudinal cognitive performance in a sample of Black adults. Two hundred fifty-seven Black participants enrolled in the African Americans Fighting Alzheimer's in Midlife (AA-FAIM) study underwent at least one cognitive assessment visit; a subset of n = 235 had plasma samples. Baseline IICV was calculated as the standard deviation across participants' z scores on five cognitive measures: Rey Auditory Verbal Learning Test Delayed Recall, Trail Making Test Parts A and B (Trails A and B), and Boston Naming Test. Using mixed effects regression models, we compared concurrent and longitudinal models to baseline plasma Aβ42/40 or IICV by age interactions. PrecivityAD assays quantified baseline plasma Aβ42/40. IICV was associated with concurrent/baseline performance on several outcomes but did not modify associations between age and cognitive decline. In contrast, plasma Aβ42/40 was unrelated to baseline cognitive performance, but a pattern emerged in interactions with age in longitudinal models of Trails A and B and Rey Auditory Verbal Learning Test total learning trials. Although not significant after correcting for multiple comparisons, low Aβ42/40 was associated with faster cognitive declines over time. Our results are promising as they extend existing findings to an Black American sample using low-cost, low-burden methods that can be implemented outside of a research center, thus supporting efforts for inclusive AD biomarker research.

A-54 Increased Symptoms During a Post-Concussion Neuropsychological Evaluation are Associated with Intraindividual Cognitive Variability and Anxiety

Abstract Purpose To examine the relationship between self-reported affect, cognitive functioning, and increased symptoms during a post-concussion neuropsychological evaluation. Methods 46 collegiate athletes (M=34, F=12) completed a comprehensive neuropsychological evaluation within 14 days of concussion, including measures of depression (Beck Depression Inventory-Fast Screen (BDI-FS)) and anxiety (NEO Five Factor Inventory (NEO-FFI) Anxiety Subscale). Suggested cutoffs for significant depression (BDI-FS ≥4) and anxiety (NEO-FFI Anxiety Subscale ≥10) symptomatology were utilized. The 21-item Post-Concussion Scale (PCS) was administered at the beginning (Pre-PCS) and end (Post-PCS) of testing. A difference score was calculated by subtracting Post-PCS from Pre-PCS. Composites of mean neuropsychological performance and two intraindividual variability (IIV) indices (average standard deviation and maximum discrepancy score) were created separately for two domains: memory and attention/processing speed (APS). Results Cognitive functioning explained a significant amount of the variance in Pre-Post PCS difference scores, F(6,39)=5.13, p<.001, R2=.44. Both IIV indices for memory and APS (all p’s<.02) significantly predicted difference scores, with cognitive variability increasing as Pre-Post PCS difference scores increased, but traditional mean composites did not (p’s>.05). Athletes who reported significant anxiety symptomatology (M=-4.33, SD=4.41) were significantly more likely than those who did not (M=.21, SD=3.75) to experience an increase in PCS symptoms, t(37)=2.66, p=.01, 95% CI [1.09,8.00]. There were no significant Pre-Post PCS symptom changes between athletes reporting significant depression symptomatology (M=.43, SD=5.19) or not (M=-.15, SD=4.61). Conclusions Higher IIV in cognitive functioning and worse anxiety symptomatology, but not traditional mean differences in cognitive functioning or depression symptomatology, were associated with an increase in symptoms during a post-concussion evaluation.

51. The Utility of Cognitive Intra-Individual Variability in Healthy Aging and Cognitive Impairment

51. The Utility of Cognitive Intra-Individual Variability in Healthy Aging and Cognitive Impairment

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

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. 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. 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. 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. 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.

Lower prospective memory is associated with higher neurocognitive dispersion in two samples of people with HIV: A conceptual replication study.

People living with HIV (PLWH) often experience deficits in the strategic/executive aspects of prospective memory (PM) that can interfere with instrumental activities of daily living. This study used a conceptual replication design to determine whether cognitive intraindividual variability, as measured by dispersion (IIV-dispersion), contributes to PM performance and symptoms among PLWH. Study 1 included 367 PLWH who completed a comprehensive clinical neuropsychological test battery, the Memory for Intentions Test (MIsT), and the Prospective and Retrospective Memory Questionnaire (PRMQ). Study 2 included 79 older PLWH who completed the Cogstate cognitive battery, the Cambridge Prospective Memory Test (CAMPROMPT), an experimental measure of time-based PM, and the PRMQ. In both studies, a mean-adjusted coefficient of variation was derived to measure IIV-dispersion using normative T-scores from the cognitive battery. Higher IIV-dispersion was significantly associated with lower time-based PM performance at small-to-medium effect sizes in both studies (mean r s =-0.30). The relationship between IIV-dispersion and event-based PM performance was comparably small in magnitude in both studies (r s =-0.19, -0.20), but it was only statistically significant in Study 1. IIV-dispersion showed very small, nonsignificant relationships with self-reported PM symptoms in both samples (r s < 0.10). Extending prior work in healthy adults, these findings suggest that variability in performance across a cognitive battery contributes to laboratory-based PM accuracy, but not perceived PM symptoms, among PLWH. Future studies might examine whether daily fluctuations in cognition or other aspects of IIV (e.g., inconsistency) play a role in PM failures in everyday life.

Intra-individual variability in cognitive performance predicts functional decline in Parkinson’s disease

Background Cognitive deficits contribute to disability in Parkinson’s disease (PD). Cognitive intra-individual variability (IIV) is associated with cognitive decline in age-related disorders, but IIV has not been related to functional ability in PD. We examined IIV in predicting functional ability in participants with PD. Methods De-identified National Alzheimer’s Coordinating Center data (N = 1,228) from baseline and follow-up visits included participants with PD propensity score matched to control participants at baseline on age (M = 72), education (M = 15), and gender (28% female). PD symptom duration averaged 6 years. Outcome measures included the Functional Ability Questionnaire (FAQ), overall test battery mean (OTBM) of ten cognitive variables, IIV calculated as the standard deviation of cognitive data for each participant, Geriatric Depression Scale (GDS), and Unified PD Rating Scale gait and posture items. Baseline FAQ status in the PD group was predicted using logistic regression with age, education, cognition, GDS, and motor function as predictors. We compared baseline characteristics of PD participants with and without functional impairment at follow up. Results PD participants showed lower OTBM and greater IIV, GDS, and motor dysfunction than controls (p < .0001). Education, OTBM, IIV, GDS, and gait predicted functional status (77% overall classification; AUC = .84). PD participants with functional impairment at follow up showed significantly lower OTBM and greater IIV, GDS, and motor dysfunction at baseline (p < .001). Conclusion IIV independently predicts functional status in participants with PD while controlling for other variables. PD participants with functional impairment at follow up showed greater IIV than those without functional impairment at follow up.

Cognitive intraindividual variability as a potential biomarker for early detection of cognitive and functional decline.

Intraindividual variability (IIV) in cognitive performance has been associated with cognitive decline and reductions in white matter integrity, but the predictive utility of IIV-between versus IIV-within domains is unknown. The present study aimed to determine if IIV-within a "frontal-subcortical" domain may be a more robust predictor of changes in general cognitive status and functional independence over time than IIV-between cognitive domains. Mixed linear modeling was used to analyze the relationship between cognitive IIV and cognitive and functional status in 651 controls, 211 people with mild cognitive impairment, and 218 people with Alzheimer's disease over a 5-year period. Both IIV-between and IIV-within a frontal-subcortical domain improved prediction of cognitive and functional declines beyond demographic characteristics, genetic risk, and vascular integrity. IIV-between showed the greatest effect over time and was driven primarily by increases in IIV-within. Cognitive IIV, especially between cognitive domains, may be useful for identifying individuals at risk for cognitive and functional decline. Findings may facilitate investigations into mechanisms underlying declines in global cerebral integrity and aid clinical trials aimed at early detection and treatment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

An examination of baseline plasma Aβ42/40 and intra‐individual cognitive variability (IICV) associations with longitudinal cognitive change in a Black Cohort: Data from the African Americans Fighting Alzheimer’s in Midlife (AA‐FAIM) study

AbstractBackgroundIn an emerging biomarker era, scientists, clinicians and patients must trust that Alzheimer’s disease (AD) biomarkers are broadly applicable across populations. However, biomarker studies inadequately include minoritized populations – largely because biomarker collection is invasive and centralized, and outreach wholly insufficient. The AA‐FAIM study collected plasma and cognitive data from a Black cohort by leveraging existing resources from the Wisconsin Alzheimer’s Disease Research Center and Wisconsin Registry for Alzheimer’s Prevention. We compared two easily‐decentralized and low‐burden options for measuring preclinical changes–either alone or combined, testing associations of baseline plasma Aβ42/40 and intra‐individual cognitive variability (IICV) with longitudinal cognition.MethodsUsing AA‐FAIM participants’ cognitive data, we derived an estimate of baseline IICV from z‐scores, representing standard deviation across five indices from list learning, executive function, and confrontational naming tests. PrecivityADTM assays quantified baseline plasma Aβ42/40. After comparing baseline IICV associations for factor‐validity (Figure 1), we conducted linear mixed‐effects models examining associations of baseline plasma Aβ42/40, IICV, or the combination of markers with longitudinal cognition on eight outcomes. Fully adjusted models included age‐at‐assessment, gender, education, and random intercepts. Benjamini‐Hochberg (BH) corrections controlling false discovery rate at 5% were applied across outcomes. Using Bayesian Information Criterion (BIC), plasma Aβ42/40 models were assessed for comparative fits with and without IICV interactions and main effects.ResultsModels included between 163‐667 observations from 56‐174 participants (Table 1). In models without plasma, IICV*age was weakly significant only for Trails tests with higher baseline IICV being associated with worse trajectories (Table 2; uncorrected/corrected p‐values=0.057/0.227 (log Trails A) and 0.044/0.227 (log Trails B)). Plasma Aβ42/40 was significantly associated with trajectories across multiple cognitive outcomes regardless of IICV inclusion (Table 3). Model estimates suggested lower baseline Aβ42/40 was associated with worse performance over time (Figures 2‐3). All interactions survived correction with IICV in the model. Without IICV, only Trails B survived correction. BIC comparisons suggested removing the IICV*age interaction from plasma models, but retaining IICV main effects.ConclusionsBaseline plasma Aβ42/40 predicted cognitive trajectory in a Black cohort. Although IICV appeared less sensitive than plasma Aβ42/40 in moderating cognitive trajectory, models including both IICV and plasma Aβ42/40 may be better in predicting trajectories.

Intraindividual variability of cognitive performance and associations with magnetic resonance imaging in aging American Indians: Data from the Strong Heart Study

AbstractBackgroundAmerican Indians present with increased risk factors for Alzheimer’s disease and related dementias (ADRDs). Intraindividual cognitive variability (IICV), which measures the variability in performance on neuropsychological tests within a person at a single time, has been proposed as a noninvasive marker of neurodegeneration and early dementia. In this study, we investigated the hypothesis that higher IICV was related to more features of neurodegeneration on magnetic resonance imaging (MRI) measurements among older American Indians.MethodAmerican Indian participants over 64 years of age who underwent MRI and completed a battery of neuropsychological tests were included in the study (N = 750). Data from three neuropsychological tests were used to compute a multidomain IICV measure of cognition along with IICV measures representing the cognitive domains of memory, executive function and processing speed. Regression models estimated IICV associations with total brain volume, hippocampal volume, and graded white matter disease, adjusting for age, sex, education, BMI, and intracranial volume.ResultMemory, executive function and processing speed, and multidomain IICV measures were associated with total brain volume before correction for multiple comparisons. After correction with Bonferroni, only higher IICV of memory was associated with lower total brain volume (Beta = −0.20; 95%CI −0.332, −0.068; p = 0.009). Furthermore, additional adjustment of mean scores from the tests used for the variability measure resulted in loss of significance for all IICV measures, with only mean scores remaining significant. Measures of IICV were not associated with hippocampal volume or white matter disease.ConclusionThese findings suggest that IICV of memory may be associated with imaging measures related to neurodegenerative injury in older American Indians. However, these associations representing variability in cognition are smaller than those representing mean cognition. More research is needed to understand the clinical and etiologic associations for IICV measures.

Construct validity of cognitive intraindividual variability: A replication study

AbstractBackgroundWe previously found intraindividual variability (IIV) in performance between cognitive domains to predict subsequent declines in cognitive and functional status over a 5‐year period in the Texas Alzheimer’s Research and Care Consortium (TARCC) Hispanic Longitudinal Cohort. However, we later examined the construct validity and predictive utility of this metric in a follow‐up study and found that IIV‐between domains was driven primarily by IIV‐within the executive function domain in the non‐Hispanic cohort and by IIV‐within the language domain in the Hispanic cohort. The present study aimed to replicate these findings in two independent samples: (1) FRONTIER, and (2) HABLE.MethodsBaseline data for cognitively normal participants in the TARCC (N = 651), HABLE (N = 1199), and FRONTIER (N = 197) studies were included for analysis in the present study. All participants ranged from 50–95 years of age with 0–22 years of education. Although cognitive measures varied across studies, mean composite and standard deviation z‐scores were calculated from similar tasks for an Attention/Processing Speed, Language, Delayed Verbal Memory, and Executive Functioning domain. Measures of functional independence also varied across studies.ResultsAcross studies, non‐Hispanic individuals were generally older with higher levels of education, fewer depressive symptoms, and higher cognitive and functional status. Only variability in the executive domain was found to consistently differ between Hispanic and non‐Hispanic individuals across studies and no consistent between‐group differences were observed in the relationship between cognitive IIV scores with each other and with clinical characteristics and measures of general cognitive and functional status.ConclusionsFindings suggest that the construct validity and predictive utility of cognitive IIV scores varies across studies differing in methodology and clinical characteristics.

MoCA Intraindividual Cognitive Variability in Older Adults With Type 1 Diabetes.

Older adults with type 1 diabetes (T1D) may have an elevated risk of developing Alzheimer disease and related dementia. Higher intraindividual cognitive variability (IICV) has been proposed as a novel risk factor of Alzheimer disease and related dementia. Here, we examined the association between cross-domain IICV measured using the Montreal Cognitive Assessment (MoCA) and cognitive impairment measured using traditional neuropsychological tests in older individuals with T1D. Participants with T1D (N=201) completed both the MoCA and a battery of traditional neuropsychological tests. Participants with cognitive impairment, determined using traditional tests, had significantly higher IICV scores and significantly lower total MoCA scores ( P <0.001). However, the effect of the total score was greater than that of the IICV score on the likelihood of cognitive impairment (total odds ratio=3.50, IICV odds ratio=2.03, P <0.001). The MoCA total score performed better than the MoCA IICV score in identifying T1D individuals classified with cognitive impairment.

Dispersion-based cognitive intra-individual variability in dementia with Lewy bodies.

Cognitive fluctuations are characteristic of dementia with Lewy bodies (DLB) but challenging to measure. Dispersion-based intra-individual variability (IIV-d) captures neurocognitive performance fluctuations across a test battery and may be sensitive to cognitive fluctuations but has not been studied in DLB. We report on 5,976 participants that completed the uniform data set 3.0 neuropsychological battery (UDS3NB). IIV-d was calculated via the intra-individual standard deviation across 12 primary UDS3NB indicators. Separate models using mean USD3NB score and the Montreal cognitive assessment (MoCA) total score tested the reproducibility of the incremental value of IIV-d over-and-above global cognition. Binary logistic regressions tested whether IIV-d could classify individuals with and without clinician-rated cognitive fluctuations. Multinomial logistic regressions tested whether IIV-d could differentiate participants with DLB, participants with Alzheimer's disease (AD), and participants with healthy cognition (CH), as well as the incremental diagnostic utility of IIV-d over-and-above clinician-rated cognitive fluctuations. IIV-d exhibited large univariate associations with clinician-rated and non-clinician-informant reported cognitive fluctuations, which persisted when adjusting for MoCA but not the full battery mean. Of diagnostic relevance, greater IIV-d was consistently associated with DLB and AD relative to CH over-and-above global cognition and clinician-rated cognitive fluctuations. Greater IIV-d was less consistently associated with an increased probability of DLB relative to AD when controlling for global cognition. IIV-d accurately differentiates DLB from CH over-and-above global cognition and clinician-rated cognitive fluctuations. IIV-d may supplement a thorough clinical interview of cognitive fluctuations and serve as a standardized performance-based indicator of this transdiagnostic phenomenon. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Supplemental Material for Cognitive Intraindividual Variability as a Potential Biomarker for Early Detection of Cognitive and Functional Decline

Supplemental Material for Cognitive Intraindividual Variability as a Potential Biomarker for Early Detection of Cognitive and Functional Decline

Intra-individual cognitive variability in neuropsychological assessment: a sign of neural network dysfunction

ABSTRACT Intra-Individual Cognitive Variability (IICV) predicts progression in neurocognitive disorders . Given important clinical applications, we investigated the association between IICV and multiple brain metrics across 17 networks to better understand the brain mechanisms underlying this performance measure. Sixty-three middle-aged and older adults without dementia underwent a neuropsychological battery, resting-state fMRI, and structural MRI scans. In a linear mixed effect model, higher IICV was associated with lower functional connectivity in control C network relative to medial occipital network (the reference). A multivariate partial least squares analysis revealed that lower mean and higher variability were both associated with lower connectivity in sensorimotor and default mode networks, while higher mean and higher variability were associated with lower volume in default mode and limbic networks. This study suggests that IICV signals widespread network dysfunction across multiple brain networks. These brain abnormalities offer new insights into mechanisms of early cognitive dysfunction. Clinical implications are discussed.

Cognitive intraindividual variability as a biomarker for functional declines in the Texas Alzheimer’s Research and Care Consortium (TARCC) Longitudinal Hispanic Cohort

AbstractBackgroundWhile intraindividual variability (IIV) in cognitive performance has been associated with increased risk for cognitive decline, the relative predictive utility of IIV‐across versus IIV‐within different cognitive domains remains unknown. Given that cognitive IIV has also been linked to age‐related reductions in white matter integrity, the current study aimed to determine if IIV‐within a “frontal‐subcortical” domain may be a more robust predictor of functional declines over time than IIV‐across cognitive domains.MethodsParticipants included 651 controls, 211 MCI and 218 AD patients enrolled in the TARCC Hispanic Longitudinal Cohort. Mixed Linear Modeling was used to examine the fixed effects of static predictors (i.e., age, education, gender, ethnicity, APOE genotype, cognitive status) at baseline, and the fixed and random effects of time‐varying covariates (i.e., depression, pulse pressure, IIV‐across domains, and IIV‐within the frontal‐subcortical domain) on changes in functional independence over 5 years.ResultsAge, education and ethnicity moderated the relationship between APOE genotype, baseline cognitive status and declines in functional independence over time. Overall, greater pulse pressure, IIV‐across domains and IIV‐within the frontal‐subcortical domain were all associated with larger decrements in functional independence over time. Although increases in IIV‐across domains were primarily driven by increases in IIV‐within the frontal‐subcortical domain over time, the former emerged as a stronger predictor of functional independence than the latter. Gender and education significantly influenced individual differences in rates of change over time, while the effects of IIV‐across domains and IIV‐within the frontal‐subcortical domain on functional declines differed from person‐to‐person. The addition of cognitive IIV predictors significantly improved model fit with a 1498.3 reduction in ‐2LL (p &lt; 0.001). The final model accounted for 97.8% of the variance in functional independence over time.ConclusionsResults suggest that IIV‐across domains may be a robust biomarker of subsequent declines in functional independence and changes in this metric are primarily driven by increasing variability across tasks dependent on frontal‐subcortical circuitry. Findings also highlight important considerations for the development of future clinical trials aimed at early prevention and treatment, including the significance of demographic and clinical characteristics in moderating the risk of decline in functional independence over time.

Cognitive Intra-individual Variability in HIV: an Integrative Review.

Nearly 30-50% of people living with HIV experience HIV-Associated Neurocognitive Disorder (HAND). HAND indicates performance at least one standard deviation below the normative mean on any two cognitive domains. This method for diagnosing or classifying cognitive impairment has utility, however, cognitive intraindividual variability provides a different way to understand cognitive impairment. Cognitive intraindividual variability refers to the scatter in cognitive performance within repeated measures of the same cognitive test (i.e., inconsistency) or across different cognitive tests (i.e., dispersion). Cognitive intraindividual variability is associated with cognitive impairment and cognitive decline in various clinical populations. This integrative review of 13 articles examined two types of cognitive intraindividual variability in people living with HIV, inconsistency and dispersion. Cognitive intraindividual variability appears to be a promising approach to detect subtle cognitive impairments that are not captured by traditional mean-based neuropsychological testing. Greater intraindividual variability in people living with HIV has been associated with: 1) poorer cognitive performance and cognitive decline, 2) cortical atrophy, both gray and white matter volume, 3) poorer everyday functioning (i.e., driving simulation performance), specifically medication adherence, and 4) even mortality. This inspires future directions for research. First, greater cognitive intraindividual variability may reflect a greater task demand on executive control to harness and regulate cognitive control over time. By improving executive functioning through cognitive training, it may reduce cognitive intraindividual variability which could slow down cognitive decline. Second, cognitive intraindividual variability may be reconsidered in prior cognitive intervention studies in which only mean-based cognitive outcomes were used. It is possible that such cognitive interventions may actually improve cognitive intraindividual variability, which could have clinical relevance.

Longitudinal association of intraindividual variability with cognitive decline and dementia: A meta-analysis.

Intraindividual variability (IIV)-variance in an individual's cognitive performance-may be associated with subsequent cognitive decline and/or conversion to dementia in older adults. This novel measure of cognition encompasses two main operationalizations: inconsistency (IIV-I) and dispersion (IIV-D), referring to variance within or across tasks, respectively. Each operationalization can also be measured with or without covariates. This meta-analytic study explores the association between IIV and subsequent cognitive outcomes regardless of operational definition and measurement approach. Longitudinal studies (N = 13) that have examined IIV in association with later cognitive decline and/or conversation to MCI/dementia were analyzed. The effect of IIV operationalization was explored. Additional subgroup analysis of measurement approaches could not be examined due to the limited number of appropriate studies available for inclusion. Meta-analytic estimates suggest IIV is associated with subsequent cognitive decline and/or conversion to MCI/dementia (r = .20, 95% CI [.09, .31]) with no significant difference between the two operationalisations observed (Q = 3.41, p = .065). Cognitive IIV, including both IIV-I and IIV-D operationalizations, appears to be associated with subsequent cognitive decline and/or dementia and may offer a novel indicator of incipient dementia in both clinical and research settings. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

A-49 Construct Validity and Predictive Utility of Cognitive Intraindividual Variability Varies Based on Ethnic Group

Abstract Objective Compare the construct validity and predictive utility of cognitive intraindividual variability (IIV) in a sample of community dwelling Hispanic and non-Hispanic older adults. Methods The present study included annual data from 651 older adult control participants (Hispanic = 293; Non-Hispanic = 358) enrolled in the Texas Alzheimer’s Research and Care Consortium for at least 5 years. Mean composite z-scores were calculated for attention, language, memory and executive function domains. IIV-across domains was calculated as the standard deviation between these composite scores, while IIV-within domain scores were computed as the absolute difference between tests in each domain. Results At baseline, Non-Hispanic individuals obtained significantly higher composite scores in each domain than their Hispanic counterparts. They also showed significantly greater variability across and within domains, with the exception of IIV-within the language domain which was significantly larger in the Hispanic group. IIV-across domains was driven primarily by IIV-within the executive function domain in the non-Hispanic cohort and by IIV-within the language domain in the Hispanic cohort. In both groups, the addition of IIV-within and -across cognitive domains at baseline significantly improved prediction of cognitive status (MMSE) after 5 years above and beyond demographic characteristics, genetic risk and vascular integrity. However, IIV-across domains was the strongest predictor in the non-Hispanic group, while IIV-within the attention domain was the strongest predictor in the Hispanic group. Conclusions Findings suggest that, while IIV-across domains is a promising preclinical biomarker of subsequent cognitive decline, its construct validity and predictive utility varies based on ethnic group.

Correction to: Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students

Correction to: Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students

Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students

Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students