Traumatic brain injury (TBI), mental health conditions (e.g., posttraumatic stress disorder [PTSD]), and vascular comorbidities (e.g., hypertension, diabetes) are highly prevalent in the Veteran population and may exacerbate age-related changes to cerebral white matter (WM). Our study examined (1) relationships between health conditions—TBI history, PTSD, and vascular risk—and cerebral WM micro- and macrostructure, and (2) associations between WM measures and cognition.

We analyzed diffusion tensor images from 183 older male Veterans (mean age = 69.18; SD = 3.61) with (n = 95) and without (n = 88) a history of TBI using tractography. Generalized linear models examined associations between health conditions and diffusion metrics. Total WM hyperintensity (WMH) volume was calculated from fluid-attenuated inversion recovery images. Robust regression examined associations between health conditions and WMH volume. Finally, elastic net regularized regression examined associations between WM measures and cognitive performance.

Veterans with and without TBI did not differ in severity of PTSD or vascular risk (p’s >0.05). TBI history, PTSD, and vascular risk were independently associated with poorer WM microstructural organization (p’s <0.5, corrected), however the effects of vascular risk were more numerous and widespread. Vascular risk was positively associated with WMH volume (p = 0.004, β=0.200, R2 = 0.034). Higher WMH volume predicted poorer processing speed (R2 = 0.052).

Relative to TBI history and PTSD, vascular risk may be more robustly associated with WM micro- and macrostructure. Furthermore, greater WMH burden is associated with poorer processing speed. Our study supports the importance of vascular health interventions in mitigating negative brain aging outcomes in Veterans.

The present study characterized heterogeneity in the cognitive profiles of monolingual and bilingual Latino older adults enrolled in the HABS-HD.

A total of 859 cognitively unimpaired older adults completed neuropsychological testing. Raw scores for cognitive tests were converted to z-scores adjusted for age, education, sex, and language of testing. A latent profile analysis (LPA) was conducted for monolingual and bilingual speaker groups. A series of 2–5 class solutions were examined, and the optimal model was selected based on fit indices, posterior probabilities, proportion of sample sizes, and pattern of scores. Identified classes were compared on sociodemographic, psychosocial, and health characteristics.

For the monolingual group (n = 365), a 3-class solution was optimal; this consisted of a Low Average Memory group with low average verbal memory performances on the SEVLT Total Learning and Delayed Recall trials, as well as an Average Cognition group and a High Average Cognition group. For the bilingual group (n = 494), a 3-class solution was observed to be optimal; this consisted of a Low Average Memory group, with low average verbal memory performances on the learning and delayed recall trials of Logical Memory; a Low Average Executive group, where performance on Trails A and B and Digit Substitution were the lowest; and a High Average Cognition group, where performance was generally in the high average range across most cognitive measures.

Cognitive class solutions differed across monolingual and bilingual groups and illustrate the need to better understand cognitive variability in linguistically diverse samples of Latino older adults.

Hispanic/Latino (H/L) older adults are at greater risk of developing Alzheimer’s disease and related dementias compared to non-Hispanic whites (NHW), and there is an urgent need to identify important factors that may help prevent and/or reduce age-related cognitive health disparities. Positive psychosocial factors, such as social support, may protect against cognitive impairment and decline. However, recent research has highlighted that the effect of social support on cognitive outcomes may differ across racial/ethnic groups. Given the emphasis placed on family relationships and support in H/L culture, the current study sought to clarify whether H/L ethnicity moderated the association between social support and cognitive functioning in a well-characterized sample of community-dwelling older adults residing in Texas.

Participants included 766 NHW and 817 H/L (predominantly Mexican American) older adults (Mage = 66.25 ±8.64) without dementia enrolled in the Health and Aging Brain Study-Health Disparities. Participants completed study questionnaires and a comprehensive neuropsychological battery. Perceived social support was measured using the total sum score from the 12-item abbreviated version of the Interpersonal Support Evaluation List. Episodic memory performance was operationalized as the z-score composite of the immediate and delayed recall totals from the Spanish English Verbal Learning Test and the Weschler Memory Scale (WMS)-III Logical Memory 1 and 2. Executive functioning was operationalized as the z-score composite of scores from the WMS-III Digit Span, Verbal Fluency (FAS), and Trails B. Analyses of covariance were used to explore racial/ethnic group differences in self-reported levels of social support. Multiple linear regression models examined (1) ethnicity x social support interactions on cognition, and (2) ethnicity-stratified social support and cognition associations. Covariates included age, education, sex, yearly income, and depressive symptoms.

H/L older adults reported less perceived social support compared to NHWs (F = 41.16, p < .001). There were no significant ethnicity x social support interactions on episodic memory (ß = 0.04, p = .53) or executive functioning (ß = 0.004, p = .95). However, stratified models revealed that more social support was associated with better memory performance in H/Ls (ß = 0.08, p = .01), but not in NHWs (ß = 0.0004, p = .99). No significant associations between social support and executive functioning were observed amongst H/Ls (ß = -0.01, p = .60) or NHWs (ß = 0.04, p = .29).

Although H/Ls reported lower levels of social support relative to NHWs, we observed that social support was linked to better memory performance within the H/L group only. Results suggest that culturally tailored interventions which encourage strong interpersonal relationships and caring for family could enhance social support in H/Ls and thus help to prevent memory decline. Future work should focus on the development of assessment measures that better characterize unique cultural elements of social support within H/Ls, such as multigenerational households, and explore the direct effects of social support on brain metrics.

Alterations in cerebral blood flow (CBF) are associated with risk of cognitive decline and Alzheimer’s disease (AD). Although apolipoprotein E (APOE) ε4 and greater vascular risk burden have both been linked to reduced CBF in older adults, less is known about how APOE ε4 status and vascular risk may interact to influence CBF. We aimed to determine whether the effect of vascular risk on CBF varies by gene dose of APOE ε4 alleles (i.e., number of e4 alleles) in older adults without dementia.

144 older adults without dementia from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) underwent arterial spin labeling (ASL) and T1-weighted MRI, APOE genotyping, fluorodeoxyglucose positron emission tomography (FDG-PET), lumbar puncture, and blood pressure assessment. Vascular risk was assessed using pulse pressure (systolic blood pressure -diastolic blood pressure), which is thought to be a proxy for arterial stiffening. Participants were classified by number of APOE ε4 alleles (n0 alleles = 87, m allele = 46, n2 alleles = 11). CBF in six FreeSurfer-derived a priori regions of interest (ROIs) vulnerable to AD were examined: entorhinal cortex, hippocampus, inferior temporal cortex, inferior parietal cortex, rostral middle frontal gyrus, and medial orbitofrontal cortex. Linear regression models tested the interaction between categorical APOE ε4 dose (0, 1, or 2 alleles) and continuous pulse pressure on CBF in each ROI, adjusting for age, sex, cognitive diagnosis (cognitively unimpaired vs. mild cognitive impairment), antihypertensive medication use, cerebral metabolism (FDG-PET composite), reference CBF region (precentral gyrus), and AD biomarker positivity defined using the ADNI-optimized phosphorylated tau/ß-amyloid ratio cut-off of > 0.0251 pg/ml.

A significant pulse pressure X APOE ε4 dose interaction was found on CBF in the entorhinal cortex, hippocampus, and inferior parietal cortex (ps < .005). Among participants with two e4 alleles, higher pulse pressure was significantly associated with lower CBF (ps < .001). However, among participants with zero or one ε4 allele, there was no significant association between pulse pressure and CBF (ps > .234). No significant pulse pressure X APOE ε4 dose interaction was found in the inferior temporal cortex, rostral middle frontal gyrus, or medial orbitofrontal cortex (ps > .109). Results remained unchanged when additionally controlling for general vascular risk assessed via the modified Hachinski Ischemic Scale.

These findings demonstrate that the cross-sectional association between pulse pressure and region-specific CBF differs by APOE ε4 dose. In particular, a detrimental effect of elevated pulse pressure on CBF in AD-vulnerable regions was found only among participants with the e4/e4 genotype. Our findings suggest that pulse pressure may play a mechanistic role in neurovascular unit dysregulation for those genetically at greater risk for AD. Given that pulse pressure is just one of many potentially modifiable vascular risk factors for AD, future studies should seek to examine how these other factors (e.g., diabetes, high cholesterol) may interact with APOE genotype to affect cerebrovascular dysfunction.

Metabolic Syndrome (MetS) is a constellation of deleterious cardiometabolic health conditions (e.g., diabetes, hypertension) that have been linked to cognitive impairment and accelerated cognitive decline in older adults. Research has shown that Latinos are at increased risk for developing MetS relative to non-Latino Whites and the prevention, maintenance, and treatment of cardiometabolic risk factors are largely contingent upon health insurance status. Within the United States there are considerable state-based differences in eligibility and access to health insurance coverage. Although Texas has the second largest population of Latinos, they are one of the most underinsured groups within the state. There is some evidence to suggest that inconsistent healthcare is associated with cognitive impairment among underserved/underprivileged groups. The current study sought to examine whether insurance status moderates the association between MetS and cognitive functioning in an effort to inform public health policy initiatives vital to reducing age-related health disparities amongst Latino older adults residing in Texas.

The study sample included 850 primarily Spanish-speaking (67.6%) Latino older adults (mean age = 63.1±7.81) largely of Mexican origin/descent (95%) enrolled in the Health and Aging Brain Study-Health Disparities. All participants completed neuropsychological testing, a health exam, and questions about health insurance coverage. MetS status (MetS+ vs. MetS-) was determined by abnormal clinical abdominal obesity, triglycerides, high-density lipoprotein, blood pressure, and fasting glucose values. Health insurance status was determined by current enrollment in any private or public insurance plan. Cognition was assessed with Digit Span, Logical Memory I and II, Trail Making Test (A and B), Spanish-English Verbal Learning Test, and Letter Fluency (FAS). Raw scores were converted to z-scores which were subsequently averaged into two distinct memory and executive functioning composite scores. ANCOVAs controlling for age, sex, education, APOE e4 positivity, annual income, and primary language status were used examine health insurance status x MetS interactions on cognitive composites.

Approximately 54.6% of the sample met clinical criteria for MetS+ and 23.6% endorsed having no health insurance. There were no significant group differences in the proportion of MetS+ and MetS- individuals with and without health insurance (X 2 = .002, p =.96). Results revealed there was a significant MetS x health insurance status interaction on the memory composite (F = 5.39, p = .02). Post-hoc comparisons revealed that Latino older adults without health insurance demonstrated poorer memory performance relative to those with health insurance in the MetS+ group (p=.02). In contrast, there were no significant differences in memory performance across insurance status in the MetS- group (p=.35). Finally, there was no significant MetS x health insurance interaction on executive functioning (p=.60).

Findings revealed that health insurance coverage differentially impacts memory, but not executive functioning, amongst Latinos with MetS+. Underinsured Latinos with chronic cardiometabolic health conditions may be at risk for poor memory outcomes and increasing access to affordable healthcare could help mitigate the adverse effects of MetS+ on memory. Future studies examining the relationship between health insurance, MetS status, and neuroimaging markers may yield additional insight into mechanisms underlying age-related dementia disparities.

Social determinants of health (SDoH) are structural elements of our living and working environments that fundamentally shape health risks and outcomes. The Healthy People 2030 campaign delineated SDoH into five distinct categories that include: economic stability, education access/quality, healthcare access, neighborhood and built environment, and social and community contexts. Recent research has demonstrated that minoritized individuals have greater disadvantage across SDoH domains, which has been linked to poorer cognitive performance in older adulthood. However, the independent effects of SDoH on everyday functioning across and within racial groups remains less clear. The current project explored the association between SDoH factors and 10-year change in everyday functioning in a large sample of community-dwelling Black and White older adults.

Data from 2,505 participants without dementia enrolled in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (age M=73.5; 76% women; 28% Black/African American). Sociodemographic, census, and industry classification data were reduced into five SDoH factors: economic stability, education access and quality, healthcare access and quality, neighborhood and built environment, and social and community contexts. The Observed Tasks of Daily Living, a performance-based measure of everyday functioning with tasks involving medication management, finances, and telephone use, was administered at baseline, 1-, 2-, 3-, 5, and 10-year follow up visits. Mixed-effects models with age as the timescale tested (1) racial group differences in OTDL trajectories, (2) race x SDOH interactions on OTDL trajectories, and (3) associations between SDoH and OTDL trajectories stratified within Black and White older adults. Covariates included sex/gender, vocabulary score, Mini-Mental Status Examination, depressive symptoms, visual acuity, general health, training group status, booster status, testing site, and recruitment wave.

Black older adults had a steeper decline of OTDL performance compared to Whites (linear: b = -.25, quadratic b=-.009, ps < .001). There was a significant race x social and community context interaction on linear OTDL trajectories (b =.06, p=.01), but no other significant race x SDoH interactions were observed (bs =-.007-.05, ps=.73-.11). Stratified analyses revealed lower levels of social and community context were associated with steeper age-related linear declines in OTDL performance in Black (b = .08, p=.001), but not White older adults (b =.004, p=.64). Additionally, lower levels of economic stability were associated with steeper age-related linear declines in OTDL performance in Black (b =.07, p=.04), but not White older adults (b =.01, p=.35). Finally, no significant associations between other SDoH and OTDL trajectories were observed in Black (bs = -.04-.01, ps =.09-.80) or White (bs = -.02-.003, ps=.07-.96) older adults.

SDoH, which measure aspects of structural racism, play an important role in accelerating age-related declines in everyday functioning. Lower levels of economic and community-level social resources are two distinct SDoH domains associated with declines in daily functioning that negatively impact Black, but not White, older adults. It is imperative that future efforts focus on both identifying and acting upon upstream drivers of SDoH-related inequities. Within the United States, this will require addressing more than a century of antiBlack sentiment, White supremacy, and unjust systems of power and policies designed to intentionally disadvantage minoritized groups.

Research indicates that Veterans with a history of traumatic brain injury (TBI) are at increased risk for dementia. Although the precise mechanisms underlying this relationship are poorly understood, remote TBI may exacerbate normal age-related changes to cerebral white matter (WM) and result in cognitive decline. However, Veterans commonly experience a constellation of mental (e.g., post-traumatic stress disorder [PTSD] and depression) and vascular (e.g., diabetes, hypertension, obesity) health conditions that have also been implicated in pathologic cerebral WM and cognitive aging trajectories. Therefore, the present study sought to (1) clarify the effects of remote TBI within the context of PTSD, depression, and vascular risk on WM micro- and macrostructure, and (2) explore if WM integrity is associated with cognition in a sample of Vietnam-Era Veterans.

The sample consisted of 195 male Veterans ages 60-80 (mean age=69.3) enrolled in the Department of Defense-Alzheimer’s Disease Neuroimaging Initiative (DoD-ADNI) study. 102 Veterans met criteria for TBI by sustaining a head-injury that resulted in a loss of consciousness, alteration of consciousness, or post-traumatic amnesia. Current and/or lifetime PTSD was designated by scores >30 on the Clinician-Administered PTSD Scale. The Geriatric Depression Scale was used as a continuous measure of depression. A vascular risk score (0-3) was calculated based on diabetes, hypertension, and obesity (BMI >30 kg/m2). An executive functioning composite was created by averaging sample-specific z-scores for Trail Making Tests (A and B), with higher scores indicating worse performance. Voxelwise analysis of WM microstructure (fractional anisotropy [FA]) was conducted with Tract-Based Spatial Statistics (TBSS), using non-parametric permutation testing with threshold-free cluster enhancement. SPM’s Lesion Segmentation Tool was used to investigate WM macrostructure (WM hyperintensity [WMH] volume). Lesion probability maps were masked to restrict WMH volume calculations to WM. Robust regression using M-estimation and predictive R2 calculated using 10-fold cross-validation examined WMH volume, predictor, and cognitive associations. Age was a covariate in all WM analyses, and education was a covariate in all cognitive analyses.

TBSS analysis revealed widespread, significant negative relationships between vascular risk and FA across numerous WM tracts (p’s<0.05). These associations remained significant after adjusting for TBI history, PTSD, and depression. TBSS identified significant positive relationships between executive functioning performance and FA across similar brain regions (p’s<0.05). Robust regressions revealed that vascular risk significantly predicted WMH volume (p=0.006; ß=0.161; R2=0.093), whereas TBI history, PTSD, and depression did not (p’s=0.107-0.166; ß's=-0.089-0.101). WMH volume significantly predicted executive functioning (p=0.002; ß=0.216; R2=0.105), whereas TBI history, PTSD, depression, and vascular risk did not (p’s=0.123-0.888; ß's=-0.012-0.125).

Our results suggest that vascular health, relative to remote TBI, PTSD, and depression, may be more robustly associated with cerebral WM micro- and macrostructure in older Veterans. Furthermore, poorer WM integrity is associated with poorer cognitive performance. These findings underscore the importance of vascular health interventions in preventing negative brain and cognitive aging outcomes in Veterans, independent of TBI history. Future studies might leverage other neuroimaging modalities (e.g., functional MRI) to further investigate the effects of vascular health on aging in Veterans with a history of TBI.

Prior work on associations between self-reported cognition and objective cognitive performance in Veterans has yielded mixed findings, with some evidence indicating that mild traumatic brain injury (TBI) may not impact the associations between subjective and objective cognition. However, few studies have examined these relationships in both mild and moderate-to-severe TBI, in older Veterans, and within specific cognitive domains. Therefore, we assessed the moderating effect of TBI severity on subjective and objective cognition across multiple cognitive domains.

This study included 246 predominately male Vietnam-Era Veterans (age M=69.61, SD=4.18, Range = 60.87 – 85.16) who completed neuropsychological testing and symptom questionnaires as part of the Department of Defense-Alzheimer’s Disease Neuroimaging Initiative (DoD-ADNI). Participants were classified as having history of no TBI (n=81), mild TBI (n=80), or moderate-tosevere TBI (n=85). Neuropsychological composite scores in the domains of memory, attention/executive functioning, and language were included as the outcome variables. The Everyday Cognition (ECog) measure was used to capture subjective cognition and, specifically, the ECog domain scores of memory, divided attention, and language were chosen as independent variables to mirror the objective cognitive domains. General linear models, adjusting for age, education, apolipoprotein E ε4 carrier status, pulse pressure, depressive symptom severity, and PTSD symptom severity, tested whether TBI severity moderated the associations of domain-specific subjective and objective cognition.

Across the sample, subjective memory was associated with objective memory (β=-.205, 95% CI [-.332, -.078], p=.002) and subjective language was associated with objective language (β=-.267, 95% CI [-.399, -.134], p<.001). However, the main effect of subjective divided attention was not associated with objective attention/executive functioning (p=.124). The main effect of TBI severity was not associated with any of the objective cognitive domain scores after adjusting for the other variables in the model. The TBI severity x subjective cognition interaction was significant for attention/executive functioning [F(2,234)=5.18, p=.006]. Specifically, relative to Veterans without a TBI, participants with mild TBI (β=-.311, 95% CI [-.620, -.002], p=.048) and moderate-to-severe TBI (β=-.499, 95% CI [-.806, -.193], p=.002) showed stronger negative associations between subjective divided attention and objective attention/executive functioning. TBI severity did not moderate the associations between subjective and objective cognition for memory or language domains. The pattern of results did not change when the total number of TBIs was included in the models.

In this DoD-ADNI sample, stronger associations between subjective and objective attention were evident among individuals with mild and moderate-to-severe TBI compared to Veterans without a TBI history. Attention/executive functioning measures (Trails A and B) may be particularly sensitive to detecting subtle cognitive difficulties related to TBI and/or comorbid psychiatric symptoms, which may contribute to these attention-specific findings. The strongest associations were among those with moderate-to-severe TBI, potentially because the extent to which their attention difficulties are affecting their daily lives are more apparent despite no significant differences in objective attention performance by TBI group. This study highlights the importance of assessing both subjective and objective cognition in older Veterans and the particular relevance of the attention domain within the context of TBI.

Veterans with a history of mild traumatic brain injury (mTBI) often endorse enduring postconcussive symptoms (PCS) including cognitive and neuropsychiatric complaints. However, although several studies have shown associations between these complaints and brain structure and cerebrovascular function, few studies have examined relationships between structural and functional brain alterations and PCS in the context of remote mTBI. We therefore examined whether PCS were associated with cortical thickness and cerebral blood flow (CBF) in a well-characterized sample of Veterans with a history of mTBI.

116 Veterans underwent structural neuroimaging and a clinical interview to obtain detailed TBI history and injury-related information. Participants also completed the following self-report measures: the Neurobehavioral Symptom Inventory (NSI) for ratings of cognitive, emotional, somatic-sensory, and vestibular symptoms, and the Posttraumatic Stress Disorder (PTSD) Checklist for PTSD symptom severity. Regional brain thickness was indexed using FreeSurfer-derived cortical parcellations of frontal and temporal regions of interest (ROIs) including the superior frontal gyrus (SFG), middle frontal gyrus (MFG), inferior frontal gyrus (IFG), orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), medial temporal lobe (MTL), and lateral temporal lobe (LTL). A subset of Veterans (n=50) also underwent multi-phase pseudo-continuous arterial spin labeling (MPPCASL) to obtain resting CBF. T1-weighted structural and MPPCASL scans were co-registered and CBF estimates were extracted from the 7 bilateral parcellations of ROIs. To assess the relationship between NSI total and subscale scores and ROI thickness and CBF, multiple regression analyses were conducted adjusting for age, sex, and PTSD symptom severity. False Discovery Rate was used to correct for multiple comparisons.

NSI total and subscale scores were not associated with cortical thickness of any ROI. However, higher NSI scores were associated with increased ROI CBF of the SFG (q=.014) and MFG CBF (q=.014). With respect to symptom subscales, higher affective subscale scores were associated with increased SFG (q=.001), MFG (q=.001), IFG (q=.039), ACC (q=.026), and LTL CBF (q=.026); higher cognitive subscale scores were associated with increased SFG (q=.014) and MFG CBF (q=.032); and higher vestibular subscale scores were associated with increased ACC CBF (q=.021). NSI somatic-sensory subscale scores were not associated with ROI CBF.

Results demonstrate that in TBI-susceptible anterior ROIs, alterations in CBF but not cortical thickness are associated with postconcussive symptomatology in Veterans with a history of mTBI. Specifically, postconcussive total symptoms as well as affective, cognitive, and vestibular subscale symptoms were strongly linked primarily to CBF of frontal regions. Remarkably, these results indicate that enduring symptoms in generally younger samples of Veterans with head injury histories may be closely tied to cerebrovascular function rather than brain structure changes. These findings may provide a neurological basis for negative clinical outcomes (e.g., enduring PCS and poor quality of life) that is frequently reported by many individuals following mTBI. Future work is needed to examine unique effects of blast exposure as well as associations with repeated injury on brain-behavior relationships.

While loss of insight into one’s cognitive impairment (anosognosia) is a feature in Alzheimer’s disease dementia, less is known about memory self-awareness in cognitively unimpaired (CU) older adults or mild cognitive impairment (MCI) or factors that may impact self-awareness. Locus of control, specifically external locus of control, has been linked to worse cognitive/health outcomes, though little work has examined locus of control as it relates to self-awareness of memory functioning or across cognitive impairment status. Therefore, we examined associations between locus of control and memory self-awareness and whether MCI status impacted these associations.

Participants from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (mean age=73.51; 76% women; 26% Black/African American) were classified as CU (n=2177) or MCI (amnestic n=313; non-amnestic n=170) using Neuropsychological Criteria. A memory composite score measured objective memory performance and the Memory Functioning Questionnaire measured subjective memory. Memory self-awareness was defined as objective memory minus subjective memory, with positive values indicating overreporting of memory difficulties relative to actual performance (hypernosognosia) and negative values indicating underreporting (hyponosognosia). Internal (i.e., personal skills/attributes dictate life events) and external (i.e., environment/others dictate life events) locus of control scores came from the Personality in Intellectual Aging Contexts Inventory. General linear models, adjusting for age, education, sex/gender, depressive symptoms, general health, and vocabulary examined the effects of internal and external locus of control on memory self-awareness and whether MCI status moderated these associations.

Amnestic and non-amnestic MCI participants reported lower internal and higher external locus of control than CU participants. There was a main effect of MCI status on memory self-awareness such that amnestic MCI participants showed the greatest degree of hyponosognosia/underreporting, followed by non-amnestic MCI, and CU participants slightly overreported their memory difficulties. While, on average, participants were fairly accurate at reporting their degree of memory difficulty, internal locus of control was negatively associated with self-awareness such that higher internal locus of control was associated with greater underreporting (ß=-.127, 95% CI [-.164, -.089], p<.001). MCI status did not moderate this association. External locus of control was positively associated with self-awareness such that higher external locus of control was associated with greater hypernosonosia/overreporting (ß=.259, 95% CI [.218, .300], p<.001). Relative to CU, amnestic, but not non-amnestic, MCI showed a stronger association between external locus of control and memory self-awareness. Specifically, higher external locus of control was associated with less underreporting of cognitive difficulties in amnestic MCI (ß=.107, 95% CI [.006, .208], p=.038).

In CU participants, higher external locus of control was associated with greater hypernosognosia/overreporting. In amnestic MCI, the lower external locus of control associations with greater underreporting of objective cognitive difficulties suggests that perhaps reduced insight in some people with MCI may result in not realizing the need for external supports, and therefore not asking for help from others. Alternatively, in amnestic participants with greater external locus of control, perhaps the environmental cues/feedback translate to greater accuracy in their memory self-perceptions. Longitudinal analyses are needed to determine how memory self-awareness is related to future cognitive declines.

The apolipoprotein E (APOE) gene has been identified as a major risk factor for the development of Alzheimer’s disease in late life. Research has shown that APOE e4 allele carriers demonstrate poorer memory performance and accelerated cognitive decline relative to non-carriers, and there is a need to identify potential factors of resiliency against the negative effects of e4 on cognition. Social support may represent one potential mechanism given that higher levels of social support have been linked to better cognitive and functional outcomes in older adults. Thus, the current study sought to examine whether social support moderates the relationship between APOE e4 status and subjective and objective memory performance in a large community-based sample of Hispanic/Latino (H/L) and Non-Hispanic White (NHW) older adults residing in Texas.

Participants included 1,564 (H/L = 808, NHW = 756) older adults (mean age = 66.36±8.68) without dementia that had enrolled in the Health and Aging Brain Study-Health Disparities. Participants completed study questionnaires and a comprehensive neuropsychological battery. Apolipoprotein e4 status (e4 carriers vs. non-carriers) was determined by possession of at least one e4 allele. Perceived social support was measured using the total score from the abbreviated 12-item version of the Interpersonal Support Evaluation List. Objective memory performance was assessed using a z-score composite of Story A and B from the Weschler Memory Scale (WMS)-III and immediate and delayed recall trials from the Spanish-English Verbal Learning Test. Subjective memory was assessed using the total score from the Subject Memory Complaints Questionnaire. Race stratified multiple linear regression models, controlling for age, sex, and years of education, examined APOE e4 positivity x social support interactions on subjective and objective memory performance.

There was a significant APOE e4 genotype x social support interaction on objective memory performance (ß = -1.10, p = 0.003) in H/Ls such that higher levels of social support were associated with better memory performance in non-e4 carriers (ß = 0.14, p < .001), but not in e4 carriers (ß = -0.13, p = 0.9). In contrast, no significant APOE e4 status x social support interaction was observed on subjective memory (ß = -0.39, p = 0.35) in H/Ls. Finally, results revealed no significant APOE e4 genotype x social support interactions on subjective memory (ß = 0.14 p = 0.77) or objective memory (ß = 0.67, p = 0.11) performance in NHWs. Conclusions: Findings revealed that social support did not mitigate against the negative effects of e4 on subjective and objective memory performance in H/Ls or NHWs. However, results demonstrate that higher levels of social support are associated with better objective, but not subjective memory performance in H/Ls without the e4 genotype. These findings suggest that social support may protect against cognitive decline and enhance cognitive reserve in non-e4 carriers. Future studies should explore other potential factors of resiliency (e.g., diet, exercise) and examine the association between genetic risk and social support on neural markers (e.g., cortical thinning, hippocampal atrophy).

We examined whether intraindividual variability (IIV) across tests of executive functions (EF-IIV) is elevated in Veterans with a history of mild traumatic brain injury (mTBI) relative to military controls (MCs) without a history of mTBI. We also explored relationships among EF-IIV, white matter microstructure, and posttraumatic stress disorder (PTSD) symptoms.

A total of 77 Veterans (mTBI = 43, MCs = 34) completed neuropsychological testing, diffusion tensor imaging (DTI), and PTSD symptom ratings. EF-IIV was calculated as the standard deviation across six tests of EF, along with an EF-Mean composite. DSI Studio connectometry analysis identified white matter tracts significantly associated with EF-IIV according to generalized fractional anisotropy (GFA).

After adjusting for EF-Mean and PTSD symptoms, the mTBI group showed significantly higher EF-IIV than MCs. Groups did not differ on EF-Mean after adjusting for PTSD symptoms. Across groups, PTSD symptoms significantly negatively correlated with EF-Mean, but not with EF-IIV. EF-IIV significantly negatively correlated with GFA in multiple white matter pathways connecting frontal and more posterior regions.

Veterans with mTBI demonstrated significantly greater IIV across EF tests compared to MCs, even after adjusting for mean group differences on those measures as well as PTSD severity. Findings suggest that, in contrast to analyses that explore effects of mean performance across tests, discrepancy analyses may capture unique variance in neuropsychological performance and more sensitively capture cognitive disruption in Veterans with mTBI histories. Importantly, findings show that EF-IIV is negatively associated with the microstructure of white matter pathways interconnecting cortical regions that mediate executive function and attentional processes.

Prior work has robustly suggested that social processes in the neighborhood (i.e. informal social control, social cohesion, norms) influence child conduct problems (CP) and related outcomes, but has yet to consider how these community-level influences interact with individual-level genetic risk for CP. The current study sought to do just this, evaluating neighborhood-level social processes as etiologic moderators of child CP for the first time.

We made use of two nested samples of child and adolescent twins within the Michigan State University Twin Registry (MSUTR): 5649 families who participated in in the Michigan Twins Project (MTP) and 1013 families who participated in the Twin Study of Behavioral and Emotional Development (TBED-C). The neighborhood social processes of informal social control, social cohesion, and norms were assessed using neighborhood sampling techniques, in which residents of each twin family's neighborhood reported on the social processes in their neighborhood. Standard biometric GxE analyses evaluated the extent to which they moderated the etiology of CP.

The ‘no moderation’ model provided the best fit to the data in nearly all cases, arguing against neighborhood social processes as etiologic moderators of youth CP.

The neighborhood social processes evaluated here do not appear to exert their effects on child CP via etiologic moderation. The documented links between neighborhood social processes and child CP are thus likely to reflect a different etiologic process. Possibilities include environmental main effects of neighborhood social processes on child CP, or genotype-environment correlations.