Interactive Effect of Traumatic Brain Injury and Psychiatric Symptoms on Cognition among Late Middle-Aged Men: Findings from the Vietnam Era Twin Study of Aging

Co-Occurring Mental and Physical Health Conditions Among Older Adults With and Without Post-traumatic Stress Disorder: A Case Control Study

ObjectivesRates of post-traumatic stress disorder (PTSD) among older adults range from 0.4%-4.5%. Research examining PTSD in adults has demonstrated numerous associations between physical and mental health conditions; however, these are less well characterized in older adults. The current study aimed to identify base rates of such conditions among older adults with and without a history of PTSD.MethodIn a case control design using the National Alzheimer's Coordinating Center Uniform Data Set, adults 65 years or older from the United States who endorsed either the presence or absence of PTSD were matched by age to assess between-group differences (N = 472; 236 pairs). We examined differences across self-reported sociodemographics and physical health, mental health, and substance use histories.ResultsMore participants with a history of PTSD identified as Hispanic, non-white, non-married, and functionally independent. Compared to individuals without a history of PTSD, significantly more individuals with a history of PTSD had histories of depression, anxiety, substance abuse, Parkinson's disease, seizures, insomnia, and TBI. Among participants without PTSD history, only 14.7% reported a history of TBI, compared to 41.1% of individuals with PTSD history.ConclusionsFindings showed expected trends toward worse physical and mental health among older adults with self-reported PTSD. There was a striking difference in the frequency of TBI history between participants with and without PTSD. These findings underscore a need to assess for PTSD among older adults, particularly those reporting a history of TBI.

Severe Cognitive Impairment in Trauma-Affected Refugees-Exploring the Impact of Traumatic Brain Injury

Background/Objectives: This study explores the relationship between cognitive performance measured by the Symbol Digit Modality Test (SDMT) and the severity of self-reported head injury, traumatic brain injury (TBI), post-traumatic stress disorder (PTSD), depression, pain, and psychosocial dysfunction in a population of trauma-affected refugees. Refugees, especially those who have been subjected to torture, often face various difficulties, such as PTSD, depression and somatic disturbances (e.g., pain), which can significantly impact their day-to-day functioning. Methods: Participants included 141 adult refugees (38% women) with a mean age of 45.4 years (SD = 9.4) and 9.7 years (SD = 4.9) of education who were referred for treatment of post-traumatic distress to DIGNITY, Danish Institute Against Torture. Participants completed standardized self-report measures of PTSD, anxiety, depression, pain, and health-related disability and measures of trauma history, physical injuries including head injury and loss of consciousness, and the SDMT, a quick standardized performance-based measure of cognitive impairment. Results: Eighty-eight percent of participants evidenced signs of substantial cognitive impairment as indexed by lower SDMT scores. Those with a self-reported history of TBI, marked by loss of consciousness, exhibited lower SDMT scores and higher health-related disabilities. Severity of PTSD, depression, anxiety, and pain were highly correlated with lower SDMT scores. TBI history was not significantly associated with the severity of PTSD, depression, anxiety, or pain, suggesting a complex interplay among these factors. Conclusions: Cognitive impairments are prevalent in trauma-affected refugees, interacting with symptoms of post-traumatic stress and pain, likely explaining the high disability levels in this population. Further research should employ a broader range of cognitive measures and detailed investigations of head injury/TBI experiences to investigate their impact on overall functioning, treatment response, and longer-term outcomes. This study adds to a small but growing body of studies documenting cognitive impairments in trauma-affected refugees, highlighting the importance of addressing cognitive impairments in treatment for trauma-affected refugees, particularly those with histories of torture and TBI. Clinicians working with trauma-affected refugees should consider the assessment of cognitive difficulties as part of comprehensive care planning.

Association Between Traumatic Brain Injury and Cognitive Decline Among Middle-to-Older Aged Men in the Vietnam Era Twin Study of Aging

Traumatic brain injury (TBI) is associated with increased risk of dementia. However, whether TBI is associated with greater cognitive decline over time in specific cognitive domains among older adults is not well understood. This prospective cohort study used data from 1476 male Vietnam Era Twin Study of Aging participants (average age at study entry = 57.9 years, range = 51-71 years; 97.6% non-Hispanic; 92.5% White) collected from 2003 to 2019, who had complete information on prior TBI. Participants completed a comprehensive neuropsychological assessment at up to three visits over up to a 12-year follow-up period during which they also self-reported their history of TBI. Multivariable, linear mixed-effects models were used to assess associations between TBI and cognitive performance trajectories. Effect measure modification by apolipoprotein E (APOE) epsilon 4 (ε4) genotype status was assessed in a subset of participants. Thirty-one percent of participants reported a history of TBI; 29.4% were APOE ε4 carriers. There were no statistically significant associations of TBI with decline in episodic memory, executive function, or processing speed among participants overall. In models stratified by APOE ε4 carrier status, TBI was associated with a larger magnitude of decline in executive function for APOE ε4 carriers (β = -0.0181; 95% confidence interval [CI] -0.0335, -0.0027) compared to noncarriers (β = -0.0031; 95% CI -0.0128, 0.0067; P Interaction = 0.03). In sensitivity analyses, TBI earlier in life (before military induction, average age = 20 years) was associated with faster declines in executive function compared to no TBI, irrespective of APOE ε4 status. In this sample of middle-to-older aged men, TBI was associated with faster declines in executive function among APOE ε4 carriers and among those who reported TBI in early life. These findings support the importance of a life course perspective when considering factors that may influence cognitive health in aging.

Associations between MRI-assessed locus coeruleus integrity and cortical gray matter microstructure

The locus coeruleus (LC) is one of the earliest sites of tau pathology, making it a key structure in early Alzheimer's disease (AD) progression. As the primary source of norepinephrine for the brain, reduced LC integrity may have negative consequences for brain health, yet macrostructural brain measures (e.g. cortical thickness) may not be sensitive to early stages of neurodegeneration. We therefore examined whether LC integrity was associated with differences in cortical gray matter microstructure among 435 men (mean age = 67.5; range = 62-71.7). LC structural integrity was indexed by contrast-to-noise ratio (LCCNR) from a neuromelanin-sensitive MRI scan. Restriction spectrum imaging (RSI), an advanced multi-shell diffusion technique, was used to characterize cortical microstructure, modeling total diffusion in restricted, hindered, and free water compartments. Higher LCCNR (greater integrity) was associated with higher hindered and lower free water diffusion in multiple cortical regions. In contrast, no associations between LCCNR and cortical thickness survived correction. Results suggest lower LC integrity is associated with patterns of cortical microstructure that may reflect a reduction in cytoarchitectural barriers due to broader neurodegenerative processes. These findings highlight the potential utility for LC imaging and advanced diffusion measures of cortical microstructure in assessing brain health and early identification of neurodegenerative processes.

Independent and Synergistic Associations Between TBI Characteristics and PTSD Symptom Clusters on Cognitive Performance and Postconcussive Symptoms in Iraq and Afghanistan Veterans

OBJECTIVE

The investigators sought to evaluate the independent and interactive associations between mild traumatic brain injury (mTBI) characteristics and posttraumatic stress disorder (PTSD) symptoms with regard to postconcussive symptoms and cognition among treatment-seeking veterans of the U.S. conflicts in Iraq and Afghanistan.

METHODS

Sixty-seven Iraq and Afghanistan veterans who had a history of mTBI and comorbid PTSD were grouped based on injury mechanism (blast versus nonblast) and number of lifetime mTBIs (one to two versus three or more). Independent associations between mTBI characteristics and PTSD symptom clusters were evaluated with regard to cognition and postconcussive symptoms. Follow-up analyses were conducted to determine any interactive associations between TBI characteristics and PTSD symptom clusters.

RESULTS

Higher PTSD symptoms, particularly hyperarousal, were associated with poorer executive functioning and higher postconcussive symptoms. No direct relationships were observed between PTSD symptom clusters and memory or processing speed. The relationship between hyperarousal and processing speed was moderated by lifetime mTBIs, such that those with a history of at least three mTBIs demonstrated a negative association between hyperarousal and processing speed. Blast-related mTBI history was associated with reduced processing speed, compared with non-blast-related mTBI. However, an interaction was observed such that among those with blast-related mTBI history, higher re-experiencing symptoms were associated with poorer processing speed, whereas veterans without history of blast-related mTBI did not demonstrate an association between processing speed and re-experiencing symptoms.

CONCLUSIONS

Higher hyperarousal and re-experiencing symptoms were associated with reduced processing speed among veterans with repetitive and blast-related mTBI history, respectively. PTSD symptoms, specifically hyperarousal, were associated with poorer executive functioning and higher postconcussive symptoms. Limited associations were found between injury characteristics and cognition chronically following mTBI. However, these results support synergistic effects of specific PTSD symptom clusters and TBI characteristics.

The association of posttraumatic stress disorder, depression, and head injury with mid-life cognitive function in civilian women

BACKGROUND

Despite evidence linking posttraumatic stress disorder (PTSD), depression, and head injury, separately, with worse cognitive performance, investigations of their combined effects on cognition are limited in civilian women.

METHODS

The Cogstate Brief Battery assessment was administered in 10,681 women from the Nurses' Health Study II cohort, mean age 64.9 years (SD = 4.6). Psychological trauma, PTSD, depression, and head injury were assessed using online questionnaires. In this cross-sectional analysis, we used linear regression models to estimate mean differences in cognition by PTSD/depression status and stratified by history of head injury.

RESULTS

History of head injury was prevalent (36%), and significantly more prevalent among women with PTSD and depression (57% of women with PTSD and depression, 21% of women with no psychological trauma or depression). Compared to having no psychological trauma or depression, having combined PTSD and depression was associated with worse performance on psychomotor speed/attention ( β  = -.15, p = .001) and learning/working memory ( β  = -.15, p < .001). The joint association of PTSD and depression on worse cognitive function was strongest among women with past head injury, particularly among those with multiple head injuries.

CONCLUSIONS

Head injury, like PTSD and depression, was highly prevalent in this sample of civilian women. In combination, these factors were associated with poorer performance on cognitive tasks, a possible marker of future cognitive health. Head injury should be further explored in future studies of PTSD, depression and cognition in women.

Sports- and Physical Activity-Related Concussions, Binge Drinking and Marijuana Use among Adolescents: The Mediating Role of Depression and Suicidal Ideation

BACKGROUND

Although past studies have examined the adverse impact of sports- and physical activity-related concussions (SPACs) on health and mental health outcomes, there is a dearth of research investigating the association between SPACs and binge drinking and marijuana use.

OBJECTIVE

The objective of this study is to examine the cross-sectional association between SPACs and binge drinking and marijuana use among adolescents and whether symptoms of depression and suicidal ideation mediate this association.

METHODS

Data for this study came from the 2017 and 2019 National Youth Risk Behavior Survey. An analytic sample of 17,175 adolescents aged 14-18 years (50.2% male) was analyzed using binary logistic regression.

RESULTS

Of the 17,175 adolescents, 13.7% engaged in binge drinking and 19.3% used marijuana 30 days preceding the survey date. Approximately one in seven (14.1%) adolescents had SPACs during the past year. Upon controlling for the effects of other factors, adolescents who had SPACs had 1.74 times higher odds of engaging in binge drinking (AOR = 1.74, p<.001, 95% CI = 1.47-2.06) and 1.42 times higher odds of using marijuana (AOR = 1.42, p<.001, 95% CI = 1.24-1.62) than those who did not have SPACs. Symptoms of depression and suicidal ideation explained 12% of the association between SPACs and binge drinking, and 19% of the association between SPACs and marijuana use.

CONCLUSIONS

Understanding the association between SPACs and substance use and mental health could contribute to early identification of adolescents who may engage in substance use.

Distant histories of mild traumatic brain injury exacerbate age-related differences in white matter properties

We examined associations of distant histories of mild traumatic brain injury (mTBI) with non-linear and linear trajectories of white matter (WM) properties across a wide age range (23-77). Diffusion tensor imaging (DTI) data obtained from 171 Veterans with histories of clinically diagnosed mTBIs and 115 controls were subjected to tractography, isolating 20 major WM tracts. Non-linear and linear effects of age on each tract's diffusion properties were examined in terms of their interactions with group (mTBI and control). The non-linear model revealed 7 tracts in which the mTBI group's DTI metrics rapidly deviated from control trajectories in middle and late adulthoods, despite the injuries having occurred in the late 20s, on average. In contrast, no interactions between prior injuries and age were detected when examining linear trajectories. Distant mTBIs may thus accelerate normal age-related trajectories of WM degeneration much later in life. As such, life-long histories of head trauma should be assessed in all patients in their mid-to-late adulthoods, whether neurologically healthy or presenting with seemingly unrelated neuropathology.

Coordinating Global Multi-Site Studies of Military-Relevant Traumatic Brain Injury: Opportunities, Challenges, and Harmonization Guidelines

Traumatic brain injury (TBI) is common among military personnel and the civilian population and is often followed by a heterogeneous array of clinical, cognitive, behavioral, mood, and neuroimaging changes. Unlike many neurological disorders that have a characteristic abnormal central neurologic area(s) of abnormality pathognomonic to the disorder, a sufficient head impact may cause focal, multifocal, diffuse or combination of injury to the brain. This inconsistent presentation makes it difficult to establish or validate biological and imaging markers that could help improve diagnostic and prognostic accuracy in this patient population. The purpose of this manuscript is to describe both the challenges and opportunities when conducting military-relevant TBI research and introduce the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Military Brain Injury working group. ENIGMA is a worldwide consortium focused on improving replicability and analytical power through data sharing and collaboration. In this paper, we discuss challenges affecting efforts to aggregate data in this patient group. In addition, we highlight how "big data" approaches might be used to understand better the role that each of these variables might play in the imaging and functional phenotypes of TBI in Service member and Veteran populations, and how data may be used to examine important military specific issues such as return to duty, the late effects of combat-related injury, and alteration of the natural aging processes.

Pupillary dilation responses as a midlife indicator of risk for Alzheimer's disease: association with Alzheimer's disease polygenic risk

Locus coeruleus (LC) tau accumulation begins early. Targeting LC (dys)function might improve early identification for Alzheimer's disease (AD) risk. Pupillary responses during cognitive tasks are driven by the LC and index cognitive effort. Despite equivalent task performance, adults with mild cognitive impairment have greater pupil dilation/effort during digit span than cognitively normal (CN) individuals. We hypothesized that AD polygenic risk scores (AD-PRSs) would be associated with pupillary responses in middle-aged CN adults. Pupillary responses during digit span tasks were heritable (h2 = 0.30-0.36) in 1119 men aged 56-66 years. In a CN subset-all with comparable span capacities (n = 539)-higher AD-PRSs were associated with greater pupil dilation/effort in a high (9-digit) cognitive load condition (Cohen's d = 0.36 for upper vs. lower quartile of AD-PRS distribution). Results held up after controlling for APOE genotype. Results support pupillary response-and by inference, LC dysfunction-as a genetically mediated biomarker of early mild cognitive impairment/AD risk. In combination with other biomarkers, task-evoked pupillary responses may provide additional information for early screening of genetically at-risk individuals even before cognitive declines.

Predominantly global genetic influences on individual white matter tract microstructure

Individual differences in white matter tract microstructure, measured with diffusion tensor imaging (DTI), demonstrate substantial heritability. However, it is unclear to what extent this heritability reflects global genetic influences or tract-specific genetic influences. The goal of the current study was to quantify the proportion of genetic and environmental variance in white matter tracts attributable to global versus tract-specific influences. We assessed fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) across 11 tracts and 22 subdivisions of these tracts in 392 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). In principal component analyses of the 11 white matter tracts, the first component, which represents the global signal, explained 50.1% and 62.5% of the variance in FA and MD, respectively. Similarly, the first principal component of the 22 tract subdivisions explained 38.4% and 47.0% of the variance in FA and MD, respectively. Twin modeling revealed that DTI measures of all tracts and subdivisions were heritable, and that genetic influences on global FA and MD accounted for approximately half of the heritability in the tracts or tract subdivisions. Similar results were observed for the AD and RD diffusion metrics. These findings underscore the importance of controlling for DTI global signals when measuring associations between specific tracts and outcomes such as cognitive ability, neurological and psychiatric disorders, and brain aging.