Discriminating Mild Traumatic Brain Injury and Posttraumatic Stress Disorder Using Latent Neuroimaging and Neuropsychological Profiles in Active-Duty Military Service Members.

OBJECTIVE: Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) commonly occur among military Service Members and Veterans and have heterogenous, but also overlapping symptom presentations, which often complicate the diagnoses of underlying impairments and development of effective treatment plans. Thus, we sought to examine whether the combination of whole brain gray matter (GM) and white matter (WM) structural measures with neuropsychological performance can aid in the classification of military personnel with mTBI and PTSD. METHODS: Active-Duty US Service Members ( n = 156; 87.8% male) with a history of mTBI, PTSD, combined mTBI+PTSD, or orthopedic injury completed a neuropsychological battery and T1- and diffusion-weighted structural neuroimaging. Cortical, subcortical, ventricular, and WM volumes and whole brain fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were calculated. Latent profile analyses were performed to determine how the GM and WM indicators, together with neuropsychological indicators, classified individuals. RESULTS: For both GM and WM, respectively, a 4-profile model was the best fit. The GM model identified greater ventricular volumes in Service Members with cognitive symptoms, including those with a diagnosis of mTBI, either alone or with PTSD. The WM model identified reduced FA and elevated RD in those with psychological symptoms, including those with PTSD or mTBI and comorbid PTSD. However, contrary to expectation, a global neural signature unique to those with comorbid mTBI and PTSD was not identified. CONCLUSIONS: The findings demonstrate that neuropsychological performance alone is more robust in differentiating Active-Duty Service Members with mTBI and PTSD, whereas global neuroimaging measures do not reliably differentiate between these groups.

Latent Neuropsychological Profiles to Discriminate Mild Traumatic Brain Injury and Posttraumatic Stress Disorder in Active-Duty Service Members.

OBJECTIVE: To determine whether cognitive and psychological symptom profiles differentiate clinical diagnostic classifications (eg, history of mild traumatic brain injury [mTBI] and posttraumatic stress disorder [PTSD]) in military personnel. METHODS: US Active-Duty Service Members ( N = 209, 89% male) with a history of mTBI ( n = 56), current PTSD ( n = 23), combined mTBI + PTSD ( n = 70), or orthopedic injury controls ( n = 60) completed a neuropsychological battery assessing cognitive and psychological functioning. Latent profile analysis was performed to determine how neuropsychological outcomes of individuals clustered together. Diagnostic classifications (ie, mTBI, PTSD, mTBI + PTSD, and orthopedic injury controls) within each symptom profile were examined. RESULTS: A 5-profile model had the best fit. The profiles differentiated subgroups with high (34.0%) or normal (21.5%) cognitive and psychological functioning, cognitive symptoms (19.1%), psychological symptoms (15.3%), and combined cognitive and psychological symptoms (10.0%). The symptom profiles differentiated participants as would generally be expected. Participants with PTSD were mainly represented in the psychological symptom subgroup, while orthopedic injury controls were mainly represented in the high-functioning subgroup. Further, approximately 79% of participants with comorbid mTBI and PTSD were represented in a symptomatic group (∼24% = cognitive symptoms, ∼29% = psychological symptoms, and 26% = combined cognitive/psychological symptoms). Our results also showed that approximately 70% of military personnel with a history of mTBI were represented in the high- and normal-functioning groups. CONCLUSIONS: These results demonstrate both overlapping and heterogeneous symptom and performance profiles in military personnel with a history of mTBI, PTSD, and/or mTBI + PTSD. The overlapping profiles may underscore why these diagnoses are often difficult to diagnose and treat, but suggest that advanced statistical models may aid in identifying profiles representing symptom and cognitive performance impairments within patient groups and enable identification of more effective treatment targets.

Hypothermia for Patients Requiring Evacuation of Subdural Hematoma: A Multicenter Randomized Clinical Trial.

BACKGROUND: Hypothermia is neuroprotective in some ischemia-reperfusion injuries. Ischemia-reperfusion injury may occur with traumatic subdural hematoma (SDH). This study aimed to determine whether early induction and maintenance of hypothermia in patients with acute SDH would lead to decreased ischemia-reperfusion injury and improve global neurologic outcome. METHODS: This international, multicenter randomized controlled trial enrolled adult patients with SDH requiring evacuation of hematoma within 6 h of injury. The intervention was controlled temperature management of hypothermia to 35 °C prior to dura opening followed by 33 °C for 48 h compared with normothermia (37 °C). Investigators randomly assigned patients at a 1:1 ratio between hypothermia and normothermia. Blinded evaluators assessed outcome using a 6-month Glasgow Outcome Scale Extended score. Investigators measured circulating glial fibrillary acidic protein and ubiquitin C-terminal hydrolase L1 levels. RESULTS: Independent statisticians performed an interim analysis of 31 patients to assess the predictive probability of success and the Data and Safety Monitoring Board recommended the early termination of the study because of futility. Thirty-two patients, 16 per arm, were analyzed. Favorable 6-month Glasgow Outcome Scale Extended outcomes were not statistically significantly different between hypothermia vs. normothermia groups (6 of 16, 38% vs. 4 of 16, 25%; odds ratio 1.8 [95% confidence interval 0.39 to ∞], p = .35). Plasma levels of glial fibrillary acidic protein (p = .036), but not ubiquitin C-terminal hydrolase L1 (p = .26), were lower in the patients with favorable outcome compared with those with unfavorable outcome, but differences were not identified by temperature group. Adverse events were similar between groups. CONCLUSIONS: This trial of hypothermia after acute SDH evacuation was terminated because of a low predictive probability of meeting the study objectives. There was no statistically significant difference in functional outcome identified between temperature groups.

A Longitudinal Investigation of Sleep Quality in Adolescents and Young Adults After Mild Traumatic Brain Injury.

OBJECTIVE AND BACKGROUND: We examined sleep-related problems in adolescents and young adults after a mild traumatic brain injury (MTBI) or orthopedic injury. We extended the analysis of data from a study of early emotional and neuropsychological sequelae in these populations (McCauley et al. 2014. J Neurotrauma. 31:914). METHODS: We gave the Pittsburgh Sleep Quality Index to 77 participants with MTBI, 71 with orthopedic injury, and 43 non-injured controls. The age range was 12 to 30 years. We tested sleep quality within 96 hours of injury and at 1- and 3-month follow-up. Participants also completed measures of pain and fatigue, drug and alcohol use, and post-traumatic stress symptoms. RESULTS: Older participants (mean age=25 years) in the MTBI group exhibited a sharp increase in sleep-related symptoms between the baseline assessment and 1 month, and still had difficulties at 3 months. Younger participants with MTBI (mean age=15 years) and older participants with an orthopedic injury had modest increases in sleep difficulties between baseline and 1 month. The participants with MTBI also had more clinically significant sleep difficulties at all 3 assessments. At 3 months, Pittsburgh Sleep Quality Index scores in younger participants with MTBI and all participants with orthopedic injury did not differ significantly from the non-injured controls'. The controls had no significant change in their sleep symptoms during the 3 months. CONCLUSIONS: Sleep difficulties in young adults may persist for ≤3 months after MTBI and exceed those after orthopedic injury. Clinicians should seek and treat sleep-related problems after MTBI.

Dimensions of trauma and specific symptoms of complex posttraumatic stress disorder in inner-city youth: a preliminary study.

We examined relations of posttraumatic stress disorder (PTSD) symptoms with dimensions of trauma, including environment (Domestic vs. Community) and proximity (Indirect vs. Direct trauma) among inner-city youth. Participants (n = 65) reported traumatic events they had experienced on a version of the UCLA PTSD Reaction Index Trauma Exposure Screen, and reported PTSD symptoms with the PTSD Checklist--Civilian version (PCL-C). High rates of trauma and PTSD were found, consistent with other reports of inner-city youth. The 49% of youth surveyed met criteria for PTSD on the PCL-C symptom scale with a score cutoff of 35. Females reported elevated PTSD symptom scores and a higher incidence of Domestic trauma than did males but similar incidence of other trauma types. When males and females were combined, Domestic trauma significantly correlated with each of the PTSD symptom clusters of intrusions, numbing/avoidance, and hyperarousal. When participants with Community trauma were excluded from analyses to reduce confounding environmental influence, Domestic trauma marginally correlated with numbing/avoidance symptoms. Our findings suggest that Domestic trauma may result in more emotional numbing/avoidance symptoms than other types of trauma. Further analyses suggested that Community trauma may result in more intrusions and hyperarousal symptoms rather than emotional numbing. Environmental aspects of trauma, rather than the proximity of trauma, may have greater impact on presentation of PTSD. Future studies with larger samples are needed to confirm these findings.

Normative Neuroimaging Library: Designing a Comprehensive and Demographically Diverse Dataset of Healthy Controls to Support Traumatic Brain Injury Diagnostic and Therapeutic Development.

The past decade has seen impressive advances in neuroimaging, moving from qualitative to quantitative outputs. Available techniques now allow for the inference of microscopic changes occurring in white and gray matter, along with alterations in physiology and function. These existing and emerging techniques hold the potential of providing unprecedented capabilities in achieving a diagnosis and predicting outcomes for traumatic brain injury (TBI) and a variety of other neurological diseases. To see this promise move from the research lab into clinical care, an understanding is needed of what normal data look like for all age ranges, sex, and other demographic and socioeconomic categories. Clinicians can only use the results of imaging scans to support their decision-making if they know how the results for their patient compare with a normative standard. This potential for utilizing magnetic resonance imaging (MRI) in TBI diagnosis motivated the American College of Radiology and Cohen Veterans Bioscience to create a reference database of healthy individuals with neuroimaging, demographic data, and characterization of psychological functioning and neurocognitive data that will serve as a normative resource for clinicians and researchers for development of diagnostics and therapeutics for TBI and other brain disorders. The goal of this article is to introduce the large, well-curated Normative Neuroimaging Library (NNL) to the research community. NNL consists of data collected from ∼1900 healthy participants. The highlights of NNL are (1) data are collected across a diverse population, including civilians, veterans, and active-duty service members with an age range (18-64 years) not well represented in existing datasets; (2) comprehensive structural and functional neuroimaging acquisition with state-of-the-art sequences (including structural, diffusion, and functional MRI; raw scanner data are preserved, allowing higher quality data to be derived in the future; standardized imaging acquisition protocols across sites reflect sequences and parameters often recommended for use with various neurological and psychiatric conditions, including TBI, post-traumatic stress disorder, stroke, neurodegenerative disorders, and neoplastic disease); and (3) the collection of comprehensive demographic details, medical history, and a broad structured clinical assessment, including cognition and psychological scales, relevant to multiple neurological conditions with functional sequelae. Thus, NNL provides a demographically diverse population of healthy individuals who can serve as a comparison group for brain injury study and clinical samples, providing a strong foundation for precision medicine. Use cases include the creation of imaging-derived phenotypes (IDPs), derivation of reference ranges of imaging measures, and use of IDPs as training samples for artificial intelligence-based biomarker development and for normative modeling to help identify injury-induced changes as outliers for precision diagnosis and targeted therapeutic development. On its release, NNL is poised to support the use of advanced imaging in clinician decision support tools, the validation of imaging biomarkers, and the investigation of brain-behavior anomalies, moving the field toward precision medicine.

Centrum semiovale and corpus callosum integrity in relation to information processing speed in patients with severe traumatic brain injury.

OBJECTIVES: This study investigated white matter alterations in the corpus callosum (CC) and centrum semiovale (CSO), using diffusion tensor imaging and magnetization transfer imaging, in participants with severe traumatic brain injury (TBI) and related these changes to processing speed measures. PARTICIPANTS AND METHODS: Fourteen adult participants with severe TBI underwent neuroimaging and assessment, using the Symbol Digit Modalities Test and Trail-Making Test, Part B, at approximately 6 months postinjury. Thirteen demographically similar, neurologically intact adults were imaged for comparison. RESULTS: The TBI group demonstrated lower fractional anisotropy (FA) for the right CSO and higher apparent diffusion coefficient (ADC) for the CSO bilaterally than the control group. Lower FA and higher ADC were noted in all CC regions. Magnetization transfer imaging revealed smaller magnetization transfer ratios (MTRs) in the right and left CSO and CC genu and splenium. Written Symbol Digit Modalities Test performance was related to right CSO FA, bilateral CSO ADC, CC FA, and right CSO MTR, whereas oral Symbol Digit Modalities Test was related to right CSO FA, ADC, and MTR. Trail-Making Test, Part B, was related to right CSO FA and MTR. CONCLUSIONS: Advanced neuroimaging modalities such as diffusion tensor imaging and magnetization transfer imaging demonstrate significant alterations in white matter, which are related to processing speed. These techniques may be useful in quantifying the extent of injury even in normal appearing white matter after TBI.

Postconcussional Syndrome: Clinical Diagnosis and Treatment.

Diagnosis and treatment of postconcussional syndrome (PCS) is challenging because symptoms are vague, difficult to confirm, and attributable to other conditions. There are no uniformly accepted diagnostic PCS criteria. Clinical care largely focuses on symptom reduction and management. Moreover, the coronavirus disease 2019 (COVID-19) pandemic has increased the challenge because post-acute COVID-19 syndrome symptoms overlap with PCS. Future research should center on base rates of PCS-type symptoms in nonneurological samples and the identification and improved understanding of moderating variables contributing to the frequency, intensity, and duration of PCS symptoms.

Geopolitical Considerations for Working with Medically Complex Patients: A Case Illustration.

OBJECTIVE: Becoming culturally competent healthcare providers depends on the ability of practitioners to acquire knowledge, awareness, and skills related to other cultures. In building these areas of competence, it is essential to consider geopolitical factors that may influence health and health-seeking behaviors, particularly when working with immigrant populations. When care is sought, they are likely to experience significant barriers to effective care, including lack of providers who speak their language and failure of practitioners to integrate cultural beliefs into treatment plans. This is further complicated by the presence of geopolitical issues, including immigration status, war/conflict in the patient's country of origin, and/or human rights violations. METHOD: The current study uses a sample case of a Burmese-speaking, Myanmar national to illustrate a culturally informed approach to the assessment of neurobehavioral changes within complex geopolitical circumstances. The sample represents an amalgam of several patients, designed to represent common presentations, sociodemographic situations, and concerns that arise during the neuropsychological assessment process. RESULTS: Description of relevant case information including background, clinical observations, and performance on testing is provided. DISCUSSION: Awareness of the impact of these life experiences not only has the potential to deepen our understanding of our patients but also results in a more holistic, accurate, and culturally competent conceptualization of their physical and mental health needs.

Developing a Culturally Competent Neuropsychological Battery for Diagnosis of Dementia in Arabic-Speaking Patients in the United States.

OBJECTIVE: In adherence to the American Educational Research Association (AERA) guidelines on culturally informed testing practices, this paper aims to review a suggested battery of tests that is linguistically and culturally appropriate for Arabic-speaking patients and to inform the reader of the varied characteristics of the Arab world to aid in providing a culturally informed neuropsychological evaluation. METHOD: Test instruments in Arabic were identified through systematic searches of PubMed and Google Scholar, U.S.-based website searches in Arabic and French, and in consultation with Arabic-speaking cultural brokers. RESULTS: A battery assessing cognitive domains and mood was assembled using core measures that were developed using appropriate translations, cultural adaptations, and include normative data of Arabic-speaking individuals. Supplemental measures that can be administered using translated instructions and English normative data are also identified. The rationale for test selection and clinical utility, including strengths and limitations of the proposed measures is presented. CONCLUSIONS: Given the large number of Arab Americans residing in the United States combined with the dearth of Arabic speaking neuropsychologists, it is essential that non-Arabic speaking neuropsychologists educate themselves regarding culturally informed practices to better service this growing community.

Culturally Competent Approaches for Neuropsychological Assessment for Differential Diagnosis of Dementia of Korean-Speaking Patients in the United States.

OBJECTIVE: To serve the over 1.82 million people of Korean descent who reside in the United States, we assembled a core and supplemental battery of culturally and linguistically appropriate neuropsychological measures for differential diagnosis of dementia for Korean-speaking patients. METHOD: Test instruments in Korean were identified through systematic searches of PubMed and Google Scholar, US-based website searches in Korean, and in consultation with Korean-speaking cultural brokers, residing in the United States and Korea. RESULTS: A battery assessing cognitive domains and mood was assembled using core measures developed specifically for Korean-speaking individuals within the United States and supplemental English measures that can be administered using translated instructions and English normative data. The rationale for test selection and clinical utility, including strengths and limitations of the proposed measures, is presented. Additionally, a case illustration using the proposed battery is included. CONCLUSIONS: Given the large and aging population of Korean-speaking residents in the United States, it is imperative to utilize appropriately designed and normed instruments to provide culturally competent assessments to better serve the Korean community.

Developing a Culturally Competent Neuropsychological Assessment Battery for Farsi-speaking Patients with Suspected Dementia.

OBJECTIVE: To assemble a comprehensive neuropsychological battery appropriate for differential diagnosis of dementia in Farsi-speaking Iranian adults in the United States. METHOD: Systematic searches of PubMed, PsychInfo, and Google Scholar databases were conducted to obtain test instruments relevant to Farsi speakers in consultation with a Farsi-speaking cultural broker. RESULTS: A proposed battery assessing the domains of attention, executive function, verbal and visual episodic memory, language, visuospatial/visuoconstruction abilities, and mood/anxiety was assembled that includes core measures developed, either specifically for a Farsi-speaking Iranian population or validated/normed with a Farsi-speaking Iranian sample. Though not ideal, additional measures were selected that can be administered using translated instructions with English normative data to supplement the limited tests available for use in this population. The rationale for test selection and caveats for their clinical use are presented along with a case study. CONCLUSIONS: The number of neuropsychological measures available in Farsi and/or with normative data for Farsi speakers is extremely limited. Cognitive tests either developed for or validated with a bilingual Farsi-English sample also represent a significant gap in the literature. Appropriate measures for these populations are urgently needed to provide a culturally competent assessment of a growing older adult segment of an underserved community.

Developing a Culturally Competent Neuropsychological Assessment Battery for Vietnamese-speaking Patients with Suspected Dementia.

OBJECTIVES: To assemble a core battery of culturally and linguistically appropriate neuropsychological measures that can be administered to Vietnamese-speaking patients with suspected dementia. METHODS: Test instruments in Vietnamese were identified through systematic searches of PubMed, PsychInfo, and Google Scholar, and in consultation with two Vietnamese-speaking cultural brokers. RESULTS: A battery assessing the domains of attention, executive function, verbal and visual episodic memory, basic language abilities, visuospatial/visuoconstruction abilities, and mood/anxiety was assembled that included core measures developed either specifically for a Vietnamese-speaking population, or were validated/normed with a Vietnamese-speaking sample either in Vietnam or Vietnamese-speaking persons in the U.S. Supplemental measures were selected that can be administered using translated instructions with U.S. English normative data. The rationale for test selection and caveats for their clinical use are presented. CONCLUSIONS: The number of neuropsychological measures identified in Vietnamese and/or with Vietnamese normative data was sparse. Given the large and growing population of Vietnamese-speaking residents in the U.S. and the aging of these communities, it is imperative to develop additional, appropriately designed and normed instruments to provide culturally competent assessments to better serve these individuals.

Developing Culturally Competent Foreign Language Neuropsychological Assessments: Portuguese-Speaking Brazilians Living in the United States.

OBJECTIVE: As the third largest immigrant population in Houston, Texas, Brazilians represent a large bloc of the community in need of culturally and linguistically informed healthcare. In particular, the number of older adults within this population is rapidly growing, emphasizing the increased need to develop socially responsible neuropsychological assessment practices that can meet the needs of this demographic. Additionally, early symptoms of cognitive decline in Brazilian older adults can be culturally perceived as normal aging and may be masked by cultural and lifestyle practices (i.e., scaffolding by family members) that result in lack of appreciation for cognitive and functional decrements. With increased knowledge and awareness of Brazilian culture and customs, we can better understand and assess brain-behavior relationships, provide tailored assessment services, and determine the clinical implications for this population. METHODS: Test instruments in Portuguese were identified through systematic literature searches, and in consultation with clinicians serving the Portuguese community in the United States, and cultural brokers involved in Brazilian-based neuropsychology. RESULTS: A multidomain neuropsychological battery with accompanying normative data for use with adults from this community is presented. A case illustration is utilized to highlight limitations and strengths of the proposed battery, which includes core and supplemental measures. CONCLUSION: Neuropsychologists are encouraged to familiarize themselves with the proposed protocol, understand the psychometric limitations of the available tools, and make an earnest attempt toward providing socially responsible neuropsychological care via the appropriate use of culturally and linguistically tailored instruments and clinical practices.

Diffusion tensor imaging and volumetric analysis of the ventral striatum in adults with traumatic brain injury.

OBJECTIVES: The aim was to determine if there are changes in the integrity and volume of the ventral striatum following severe traumatic brain injury (TBI) and if these changes relate to executive functioning. METHODS: This study recruited 14 participants with severe TBI (mean age: 22 years) and 15 demographically-matched controls. All participants underwent magnetic resonance imaging with diffusion tensor imaging (DTI) and volumetric analysis at 6 months post-injury. Participants with TBI underwent neuropsychological testing and the relation between imaging data and cognitive performance was examined. RESULTS: Differences in DTI parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) were found between participants with TBI and controls. Correlations between right and left ventral striatum ADC and the executive functioning factor of the Neurobehavioural Rating Scale-Revised (NRS-R) were found. Correlations between right ventral striatum FA and the Controlled Oral Word Association Test, Trails Making Test Part B (TMT-B) time and NRS-R executive functioning factor were also found. Volumetric analysis showed a difference only in left nucleus accumbens between TBI and control groups. CONCLUSIONS: The integrity of the ventral striatum is affected following severe TBI. Decreases in executive functioning are related to damage to the ventral striatum and its associated structures.

A Preliminary DTI Tractography Study of Developmental Neuroplasticity 5-15 Years After Early Childhood Traumatic Brain Injury.

Plasticity is often implicated as a reparative mechanism when addressing structural and functional brain development in young children following traumatic brain injury (TBI); however, conventional imaging methods may not capture the complexities of post-trauma development. The present study examined the cingulum bundles and perforant pathways using diffusion tensor imaging (DTI) in 21 children and adolescents (ages 10-18 years) 5-15 years after sustaining early childhood TBI in comparison with 19 demographically-matched typically-developing children. Verbal memory and executive functioning were also evaluated and analyzed in relation to DTI metrics. Beyond the expected direction of quantitative DTI metrics in the TBI group, we also found qualitative differences in the streamline density of both pathways generated from DTI tractography in over half of those with early TBI. These children exhibited hypertrophic cingulum bundles relative to the comparison group, and the number of tract streamlines negatively correlated with age at injury, particularly in the late-developing anterior regions of the cingulum; however, streamline density did not relate to executive functioning. Although streamline density of the perforant pathway was not related to age at injury, streamline density of the left perforant pathway was significantly and positively related to verbal memory scores in those with TBI, and a moderate effect size was found in the right hemisphere. DTI tractography may provide insight into developmental plasticity in children post-injury. While traditional DTI metrics demonstrate expected relations to cognitive performance in group-based analyses, altered growth is reflected in the white matter structures themselves in some children several years post-injury. Whether this plasticity is adaptive or maladaptive, and whether the alterations are structure-specific, warrants further investigation.

Diffuse damage in pediatric traumatic brain injury: a comparison of automated versus operator-controlled quantification methods.

This investigation had two main objectives: 1) to assess the comparability of volumes determined by operator-controlled image quantification with automated image analysis in evaluating atrophic brain changes related to traumatic brain injury (TBI) in children, and 2) to assess the extent of diffuse structural changes throughout the brain as determined by reduced volume of a brain structure or region of interest (ROI). Operator-controlled methods used ANALYZE software for segmentation and tracing routines of pre-defined brain structures and ROIs. For automated image analyses, the open-access FreeSurfer program was used. Sixteen children with moderate-to-severe TBI were compared to individually matched, typically developing control children and the volumes of 18 brain structures and/or ROIs were compared between the two methods. Both methods detected atrophic changes but differed in the magnitude of the atrophic effect with the best agreement in subcortical structures. The volumes of all brain structures/ROIs were smaller in the TBI group regardless of method used; overall effect size differences were minimal for caudate and putamen but moderate to large for all other measures. This is reflective of the diffuse nature of TBI and its widespread impact on structural brain integrity, indicating that both FreeSurfer and operator-controlled methods can reliably assess cross-sectional volumetric changes in pediatric TBI.

Longitudinal changes in the corpus callosum following pediatric traumatic brain injury.

BACKGROUND: Atrophy of the corpus callosum (CC) is a documented consequence of moderate-to-severe traumatic brain injury (TBI), which has been expressed as volume loss using quantitative magnetic resonance imaging (MRI). Other advanced imaging modalities such as diffusion tensor imaging (DTI) have also detected white matter microstructural alteration following TBI in the CC. The manner and degree to which macrostructural changes such as volume and microstructural changes develop over time following pediatric TBI, and their relation to a measure of processing speed is the focus of this longitudinal investigation. As such, DTI and volumetric changes in the CC in participants with TBI and a comparison group at approximately 3 and 18 months after injury as well as their relation to processing speed were determined. METHODS: Forty-eight children and adolescents aged 7-17 years who sustained either complicated mild or moderate-to-severe TBI (n = 23) or orthopedic injury (OI; n = 25) were studied. The participants underwent brain MRI and were administered the Eriksen flanker task at both time points. RESULTS: At 3 months after injury, there were significant group differences in DTI metrics in the total CC and its subregions (genu/anterior, body/central and splenium/posterior), with the TBI group demonstrating significantly lower fractional anisotropy (FA) and a higher apparent diffusion coefficient (ADC) in comparison to the OI group. These group differences were also present at 18 months after injury in all CC subregions, with lower FA and a higher ADC in the TBI group. In terms of longitudinal changes in DTI, despite the group difference in mean FA, both groups generally demonstrated a modest increase in FA over time though this increase was only significant in the splenium/posterior subregion. Interestingly, the TBI group also generally demonstrated ADC increases from 3 to 18 months though the OI group demonstrated ADC decreases over time. Volumetrically, the group differences at 3 months were marginal for the midanterior and body/central subregions and total CC. However, by 18 months, the TBI group demonstrated a significantly decreased volume in all subregions except the splenium/posterior area relative to the OI group. Unlike the OI group, which showed a significant volume increase in subregions of the CC over time, the TBI group demonstrated a significant and consistent volume decrease. Performance on a measure of processing speed did not differentiate the groups at either visit, and only the OI group showed significantly improved performance over time. Processing speed was related to FA in the splenium/posterior and total CC only in the TBI group on both occasions, with a stronger relation at 18 months. CONCLUSION: In response to TBI, macrostructural volume loss in the CC occurred over time; yet, at the microstructural level, DTI demonstrated both indicators of continued maturation and development even in the damaged CC, as well as evidence of potential degenerative change. Unlike volumetrics, which likely reflects the degree of overall neuronal loss and axonal damage, DTI may reflect some aspects of postinjury maturation and adaptation in white matter following TBI. Multimodality imaging studies may be important to further understand the long-term consequences of pediatric TBI.

Event-based prospective memory performance during subacute recovery following moderate to severe traumatic brain injury in children: Effects of monetary incentives.

There are very few studies investigating remediation of event-based prospective memory (EB-PM) impairments following traumatic brain injury (TBI). To address this, we used 2 levels of motivational enhancement (dollars vs. pennies) to improve EB-PM in children with moderate to severe TBI in the subacute recovery phase. Children with orthopedic injuries (OI; n = 61), moderate (n = 28), or severe (n = 30) TBI were compared. Significant effects included Group x Motivation Condition (F(2, 115) = 3.73, p < .03). The OI (p < .002) and moderate TBI (p < .03) groups performed significantly better under the high- versus low-incentive condition; however, the severe TBI group failed to demonstrate improvement (p = .38). EB-PM performance was better in adolescents compared to younger children (p < .02). These results suggest that EB-PM can be significantly improved in the subacute phase with this level of monetary incentives in children with moderate, but not severe, TBI. Other strategies to improve EB-PM in these children at a similar point in recovery remain to be identified and evaluated.

A preliminary investigation of corpus callosum subregion white matter vulnerability and relation to chronic outcome in boxers.

Microstructural neuropathology occurs in the corpus callosum (CC) after repetitive sports concussion in boxers and can be dose-dependent. However, the specificity and relation of CC changes to boxing exposure extent and post-career psychiatric and neuropsychological outcomes are largely unknown. Using deterministic diffusion tensor imaging (DTI) techniques, boxers and demographically-matched, noncontact sport athletes were compared to address literature gaps. Ten boxers and 9 comparison athletes between 26 and 59 years old (M = 44.63, SD = 9.24) completed neuropsychological testing and MRI. Quantitative DTI metrics were estimated for CC subregions. Group×Region interaction effects were observed on fractional anisotropy (FA; η2p ≥ .21). Follow-up indicated large effects of group (η2p ≥ .26) on splenium FA (boxerscomparisons), but not radial diffusivity (RD). The group of boxers had moderately elevated number of psychiatric symptoms and reduced neuropsychological scores relative to the comparison group. In boxers, years sparring, professional bouts, and knockout history correlated strongly (r > |.40|) with DTI metrics and fine motor dexterity. In the comparison group, splenium FA correlated positively with psychiatric symptoms. In the boxer group, neuropsychological scores correlated with DTI metrics in all CC subregions. Results suggested relative vulnerability of the splenium and, to a lesser extent, the genu to chronic, repetitive head injury from boxing. Dose-dependent associations of professional boxing history extent with DTI white matter structure indices as well as fine motor dexterity were supported. Results indicated that symptoms of depression and executive dysfunction may provide the strongest indicators of global CC disruption from boxing.