One year psychosocial outcome in head injury

Reducing the incidence and mortality of traumatic brain injury in Latin America

Traumatic brain injury (TBI) represents a considerable portion of the global injury burden. The incidence of TBI will continue to increase in view of an increase in population density, an aging population, and the increased use of motor vehicles, motorcycles, and bicycles. The most common causes of TBI are falls and road traffic injuries. Deaths related to road traffic injury are three times higher in low-and middle-income countries (LMIC) than in high-income countries (HIC). The Latin American Caribbean region has the highest incidence of TBI worldwide, primarily caused by road traffic injuries. Data from HIC indicates that road traffic injuries can be successfully prevented through concerted efforts at the national level, with coordinated and multisector responses to the problem. Such actions require implementation of proven measures to address the safety of road users and the vehicles themselves, road infrastructure, and post-crash care. In this review, we focus on the epidemiology of TBI in Latin America and the implementation of solutions and preventive measures to decrease mortality and long-term disability.

Depression Severity Is Different in Dysosmic Patients Who Have Experienced Traumatic Brain Injury Compared with Those Who Have Not

Traumatic brain injury (TBI) in humans can result in olfactory, cognitive, and affective changes. Surprisingly, research on the consequences of TBI often did not control for olfactory function in the investigated groups. Consequently, the affective or cognitive differences might be misleading as related rather to different olfactory performance than to a TBI experience. Hence, our study aimed to investigate whether TBI occurrence would lead to altered affective and cognitive functioning in two groups of dysosmic patients, one with TBI experience and one without. In total, 51 patients with TBI experience and 50 controls with varied causes of olfactory loss were thoroughly examined in terms of olfactory, cognitive, and affective performance. Student t-tests demonstrated that the only significant difference between the groups appeared in the depression severity, with TBI patients being more depressed (t = 2.3, p = 0.011, Cohen's d = -0.47). Regression analyses further showed that TBI experience was significantly associated with depression severity (R2 = 0.05, F [1, 96] = 5.5, p = 0.021, beta = 1.4). In conclusion, the present study showed that TBI experience is linked to depression, which is more pronounced compared to individuals with olfactory loss without TBI.

Initial Severity of Injury Has Little Effect on the Temporal Profile of Long-Term Deficits in Locomotion, Anxiety, and Cognitive Function After Diffuse Traumatic Brain Injury

Traumatic brain injury (TBI) is associated with persistent impairments in multiple domains, including cognitive and neuropsychiatric function. Previous literature has suggested that the risk of such impairments may differ as a function of the initial severity of injury, with moderate-severe TBI (msTBI) associated with more severe cognitive dysfunction and mild TBI (mTBI) associated with a higher risk of developing an anxiety disorder. Despite this, relatively few pre-clinical studies have investigated the time course of behavioral change after different severities of injury. The current study compared the temporal profile of functional deficits incorporating locomotion, cognition, and anxiety up to 12 months post-injury after an mTBI, repeated mild TBI (rmTBI), and single msTBI in an experimental model of diffuse TBI. Injury appeared to alter the effect of aging on locomotor activity, with both msTBI and rmTBI rats showing a decrease in locomotion at 12 months relative to their earlier performance on the task, an effect not observed in shams or after a single mTBI. Further, mTBI seemed to be associated with decreased anxiety over time, as measured by increased time spent in the open arm of the elevated plus maze from 3 to 12 months post-injury. No significant findings were observed on spatial memory or volumetric magnetic resonance imaging. Future studies will need to use a more comprehensive behavioral battery, capable of capturing subtle alterations in function, and longer time points, following rats into old age, in order to more fully assess the evolution of persistent behavioral deficits in key domains after different severities of TBI, as well as their accompanying neuroimaging changes. Given the prevalence and significance of such deficits post-TBI for a person's quality of life, as well as the elevated risk of neurodegenerative disease post-injury, such investigations may play a critical role in identifying optimal windows of therapeutic intervention post-injury.

Morphometric evaluation of traumatic axonal injury and the correlation with post-traumatic cerebral atrophy and functional outcome

INTRODUCTION

Imaging plays a crucial role in the diagnosis, prognosis and follow-up of traumatic brain injury. Whereas computed tomography plays a pivotal role in the acute setting, magnetic resonance imaging is best suited to detect the true extent of traumatic brain injury, and more specifically diffuse axonal injury. Post-traumatic brain atrophy is a well-known complication of traumatic brain injury.

PURPOSE

This study investigated the correlation between diffuse axonal injury detected with fluid-attenuated inversion recovery and susceptibility-weighted imaging magnetic resonance imaging, post-traumatic brain atrophy and functional outcome (Glasgow outcome scale - extended).

MATERIALS AND METHODS

Twenty patients with a closed head injury and diffuse axonal injury detected with fluid-attenuated inversion recovery and susceptibility-weighted imaging were included. The total volumes of the diffuse axonal injury fluid-attenuated inversion recovery lesions were determined for each subject's initial (<14 days) and follow-up magnetic resonance scan (average: day 303 ± 83 standard deviation). The different brain volumes were automatically quantified using a validated and both US Food and Drug Administration-cleared and CE-marked machine learning algorithm (icobrain). The number of susceptibility-weighted imaging lesions and functional outcome scores (Glasgow outcome scale - extended) were retrieved from the Collaborative European NeuroTrauma Effectiveness Research Traumatic Brain Injury dataset.

RESULTS

The volumetric fluid-attenuated inversion recovery diffuse axonal injury lesion load showed a significant inverse correlation with functional outcome (Glasgow outcome scale - extended) (r = -0.57; P = 0.0094) and white matter volume change (r = -0.50; P = 0.027). In addition, white matter volume change correlated significantly with the Glasgow outcome scale - extended score (P = 0.0072; r = 0.58). Moreover, there was a strong inverse correlation between longitudinal fluid-attenuated inversion recovery lesion volume change and whole brain volume change (r = -0.63; P = 0.0028). No significant correlation existed between the number of diffuse axonal injury susceptibility-weighted imaging lesions, brain atrophy and functional outcome.

CONCLUSIONS

Volumetric analysis of diffuse axonal injury on fluid-attenuated inversion recovery imaging and automated brain atrophy calculation are potentially useful tools in the clinical management and follow-up of traumatic brain injury patients with diffuse axonal injury.

Cognitive Dysfunction, Brain Volumes, and Traumatic Brain Injury in Homeless Persons

Although homeless persons experience traumatic brain injury (TBI) frequently, little is known about the structural and functional brain changes in this group. We aimed to describe brain volume changes and related cognitive/motor deficits in homeless persons with or without TBI versus controls. Participants underwent T1-weighted magnetic resonance imaging (MRI), neuropsychological (NP) tests (the Grooved Pegboard Test [GPT]/Finger Tapping Test [FTT]), alcohol/drug use screens (the Alcohol Use Disorders Identification Test [AUDIT]/Drug Abuse Screening Test [DAST]), and questionnaires (the Brain Injury Screening Questionnaire [BISQ]/General Information Questionnaire [GIQ]) to determine TBI. Normalized volumes of brain substructures from MRI were derived from FreeSurfer. Comparisons were tested by Mann-Whitney U and Kruskal-Wallis rank sum tests. Leave-one-out cross-validation using random forest classifier was applied to determine the ability of predicting TBI. Diagnostic ability of this classifier was assessed using area under the receiver operating characteristic curve (AUC). Fifty-one participants—25 homeless persons (9 with TBI) and 26 controls—were included. The homeless group had higher AUDIT scores and smaller thalamus and brainstem volumes (p < 0.001) than controls. Within homeless participants, the TBI group had reduced normalized volumes of nucleus accumbens, thalamus, ventral diencephalon, and brainstem compared with the non-TBI group (p < 0.001). Homeless participants took more time on the GPT compared with controls using both hands (p < 0.0001); but the observed effects were more pronounced in the homeless group with TBI in the non-dominant hand. Homeless persons with TBI had fewer dominant hand finger taps than controls (p = 0.0096), and homeless participants with (p = 0.0148) or without TBI (p = 0.0093) tapped less than controls with their non-dominant hand. In all participants, TBI was predicted with an AUC of 0.95 (95% confidence interval [CI]: 0.89-1.00) by the classifier modeled on MRI, NP tests, and screening data combined. The MRI-data-based classifier was the best predictor of TBI within the homeless group (AUC: 0.76, 95% CI: 0.53-0.99). Normalized volumes of specific brain substructures were important indicators of TBI in homeless participants and they are important indicators of TBI in the state of homelessness itself. They may improve predictive ability of NP and screening tests in determining these outcomes.

MEG Working Memory N-Back Task Reveals Functional Deficits in Combat-Related Mild Traumatic Brain Injury

Combat-related mild traumatic brain injury (mTBI) is a leading cause of sustained cognitive impairment in military service members and Veterans. However, the mechanism of persistent cognitive deficits including working memory (WM) dysfunction is not fully understood in mTBI. Few studies of WM deficits in mTBI have taken advantage of the temporal and frequency resolution afforded by electromagnetic measurements. Using magnetoencephalography (MEG) and an N-back WM task, we investigated functional abnormalities in combat-related mTBI. Study participants included 25 symptomatic active-duty service members or Veterans with combat-related mTBI and 20 healthy controls with similar combat experiences. MEG source-magnitude images were obtained for alpha (8-12 Hz), beta (15-30 Hz), gamma (30-90 Hz), and low-frequency (1-7 Hz) bands. Compared with healthy combat controls, mTBI participants showed increased MEG signals across frequency bands in frontal pole (FP), ventromedial prefrontal cortex, orbitofrontal cortex (OFC), and anterior dorsolateral prefrontal cortex (dlPFC), but decreased MEG signals in anterior cingulate cortex. Hyperactivations in FP, OFC, and anterior dlPFC were associated with slower reaction times. MEG activations in lateral FP also negatively correlated with performance on tests of letter sequencing, verbal fluency, and digit symbol coding. The profound hyperactivations from FP suggest that FP is particularly vulnerable to combat-related mTBI.

WHODAS 2.0 Can Predict Institutionalization among Patients with Traumatic Brain Injury

Patients with traumatic brain injury (TBI) often present with disabilities associated with a high burden of care for caregivers or family members at home. When family members cannot afford to care for patients with TBI, they are often required to find them residence in long-term care institutions. To date, there are no quantitative assessment tools developed to predict institutionalization. Therefore, this study analyzed the accuracy of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) for predicting the institutionalization of patients with TBI. We designed a cross-sectional study using a nationwide disability database. We analyzed the data of 8630 patients with TBI with injury for more than six months from the Taiwan Data Bank of Persons with Disability during July 2012–October 2018. The demographic data and WHODAS 2.0 standardized scores of patients with TBI who resided in community and long-term care institutions were analyzed. Receiver operating characteristic curve (ROC) analysis was performed to investigate the predictive accuracy of WHODAS 2.0 for being institutionalized, and the optimal cut-off point was determined using the Youden index. Binary logistic regression was employed to determine the predictors of the participants being institutionalized. The WHODAS 2.0 scores in each domain were lower in the community group than in the institutionalized group. ROC analysis revealed the highest accuracy for the summary scores of WHODAS 2.0 (area under the curve = 0.769). Binary logistic regression revealed that age, gender, work status, urbanization level, socioeconomic status, severity of impairment, and WHODAS 2.0 domain scores were factors associated with the institutionalization status of patients with TBI. Our results suggest that WHODAS 2.0 may be a feasible assessment tool for predicting the institutionalization of patients with TBI.

A Detailed Overview of Long-Term Outcomes in Severe Traumatic Brain Injury Eight Years Post-injury

Background and aims: Severe traumatic brain injury is a leading cause of acquired persistent disabilities, and represents an important health and economic burden. However, the determinants of long-term outcome have rarely been systematically studied in a prospective longitudinal study of a homogeneous group of patients suffering exclusively from severe TBI

Methods: Prospective observational study of an inception cohort of adult patients with severe traumatic brain injury in the Parisian area (PariS-TBI). Outcome was assessed with face-to-face interview 8 years after Traumatic Brain Injury, focusing on impairments, activity limitations, and participation restriction.

Results: Five hundred and four patients were included between 2005 and 2007. At 8-year follow-up, 261 patients were deceased, 128 were lost to follow-up, 22 refused to participate, and 86 were finally evaluated. Age, gender, initial injury severity did not significantly differ between evaluated patients and lost to follow-up, but the latter were more frequently students or unemployed. Mean age was 41.9 (SD 13.6), 79% were male, median initial Glasgow Coma Scale Score was 6. The most frequent somatic complaints concerned balance (47.5%), motricity (31%), and headaches (36%), but these were less frequent than cognitive complaints (Memory 71%, Slowness 68%, Concentration 67%). According to the Hospital Anxiety and Depression Scale (HADS), 25 % had a score >8 for anxiety and 23.7% for depression. According to the Extended Glasgow Outcome Scale, 19.8% remained severely disabled, 46.5% moderately disabled, 33.7% had a good recovery. Older age, longer education duration, lower functional status upon intensive care discharge, and more severe 8-year dysexecutive problems were significantly associated with a lower Extended Glasgow Outcome Scale score in multivariable analysis. At 8 years, 48.7% of patients were employed in a productive job. Of those, 38% declared a salary loss since traumatic brain injury. Unemployment was significantly associated with lower 1-year GOSE score and more severe 8-year dysexecutive problems.

Conclusions: These results from an inception cohort study highlight the fact that long-term outcome after severe TBI is determined by a complex combination of injury-related, demographic and neuropsychological factors. Long after the injury, persisting impairments still interfere with social integration, and participation.

Altered Resting Functional Connectivity Is Related to Cognitive Outcome in Males With Moderate-Severe Traumatic Brain Injury

TBI results in significant cognitive impairments and in altered brain functional connectivity. However, no studies explored so far, the relationship between global functional connectivity and cognitive outcome in chronic moderate-severe TBI. This proof of principle study employed the intrinsic connectivity contrast, an objective voxel-based metric of global functional connectivity, in a small sample of chronic moderate-severe TBI participants and a group of healthy controls matched on gender (males), age, and education. Cognitive tests assessing executive functions, verbal memory, visual memory, attention/organization, and cognitive reserve were administered. Group differences in terms of global functional connectivity maps were assessed and the association between performance on the cognitive measures and global functional connectivity was examined. Next, we investigated the spatial extent of functional connectivity in the brain regions found to be associated with cognitive performance, using traditional seed-based analyses. Global functional connectivity of the TBI group was altered, compared to the controls. Moreover, the strength of global functional connectivity in affected brain areas was associated with cognitive outcome. These findings indicate that impaired global functional connectivity is a significant consequence of TBI suggesting that cognitive impairments following TBI may be partly attributed to altered functional connectivity between brain areas involved in the specific cognitive functions.

Affective, neurocognitive and psychosocial disorders associated with traumatic brain injury and post-traumatic epilepsy

Survivors of traumatic brain injury (TBI) often develop chronic neurological, neurocognitive, psychological, and psychosocial deficits that can have a profound impact on an individual's wellbeing and quality of life. TBI is also a common cause of acquired epilepsy, which is itself associated with significant behavioral morbidity. This review considers the clinical and preclinical evidence that post-traumatic epilepsy (PTE) acts as a 'second-hit' insult to worsen chronic behavioral outcomes for brain-injured patients, across the domains of emotional, cognitive, and psychosocial functioning. Surprisingly, few well-designed studies have specifically examined the relationship between seizures and behavioral outcomes after TBI. The complex mechanisms underlying these comorbidities remain incompletely understood, although many of the biological processes that precipitate seizure occurrence and epileptogenesis may also contribute to the development of chronic behavioral deficits. Further, the relationship between PTE and behavioral dysfunction is increasingly recognized to be a bidirectional one, whereby premorbid conditions are a risk factor for PTE. Clinical studies in this arena are often challenged by the confounding effects of anti-seizure medications, while preclinical studies have rarely examined an adequately extended time course to fully capture the time course of epilepsy development after a TBI. To drive the field forward towards improved treatment strategies, it is imperative that both seizures and neurobehavioral outcomes are assessed in parallel after TBI, both in patient populations and preclinical models.

Childhood Traumatic Brain Injury and the Associations With Risk Behavior in Adolescence and Young Adulthood: A Systematic Review

OBJECTIVE

To systematically review the evidence that childhood traumatic brain injury (TBI) is associated with risk behavior in adolescence and young adulthood. Risk behavior included one or more of the following: use of substances, including alcohol, tobacco, and illicit substances; involvement in criminal behavior; and behavioral issues with conduct.

METHODS

A literature search was conducted using these terms: child, pediatric, traumatic brain injury, head injury, adolescent, psychosocial, antisocial, conduct, substance use. Studies describing original research were included if they reported outcomes over the age of 13 years in participants who sustained a TBI between birth and age 13 years.

RESULTS

Six journal articles were reviewed based on 4 separate studies. Three articles indicated a relationship between childhood TBI and increased problematic substance use in adolescence and young adulthood. Three articles supported an association between childhood TBI and later externalizing behavior; however, 2 articles did not support this link.

CONCLUSION

More research is warranted to explore the association between childhood TBI and later risk behavior as the relationship is not currently understood. Future research should build on existing longitudinal research with continued use of medical records for identifying TBI and inclusion of a non-brain-related trauma group to control for general injury effects.

Using game authoring platforms to develop screen-based simulated functional assessments in persons with executive dysfunction following traumatic brain injury

The assessment of functional status is a critical component of clinical neuropsychological evaluations used for both diagnostic and therapeutic purposes in patients with cognitive brain disorders. There are, however, no widely adopted neuropsychological tests that are both ecologically valid and easily administered in daily clinical practice. This discrepancy is a roadblock to the widespread adoption of functional assessments. In this paper, we propose a novel approach using a serious game authoring platform (eAdventure) for creating screen-based simulated functional assessments. We created a naturalistic functional task that consisted of preparing a cup of tea (SBS-COT) and applied the assessment in a convenience sample of eight dyads of therapists/patients with mild executive dysfunction after traumatic brain injury. We had three main aims. First, we performed a comprehensive review of executive function assessment in activities of daily living. Second, we were interested in measuring the feasibility of this technology with respect to staffing, economic and technical requirements. Third, a serious game was administered to patients to study the feasibility of this technology in the clinical context (pre-screening test). In addition, quantitative (Technology Acceptance Model (TAM) questionnaires) and qualitative (semistructured interviews) evaluations were applied to obtain user input. Our results suggest that the staffing, economic and technical requirements of the SBS-COT are feasible. The outcomes of the pre-screening test provide evidence that this technology is useful in the functional assessment of patients with executive dysfunction. In relation to subjective data, the TAM questionnaire showed good user acceptability from a professional perspective. Interview analyses with professionals and patients showed positive experiences related to the use of the SBS-COT. Our work indicates that the use of these types of authoring platforms could have positive long-term implications for neuropsychological research, opening the door to more reproducible, cooperative and efficient research by allowing the facilitated production, reuse and sharing of neuropsychological assessment tools.

Cognitive and psychosocial function in retired professional hockey players

BACKGROUND AND OBJECTIVE

The relationship between repeated concussions and neurodegenerative disease has received significant attention, particularly research in postmortem samples. Our objective was to characterise retired professional ice hockey players' cognitive and psychosocial functioning in relation to concussion exposure and apolipoprotein ε4 status.

METHODS

Alumni athletes (N=33, aged 34-71 years) and an age-matched sample of comparison participants (N=18) were administered measures of cognitive function and questionnaires concerning psychosocial and psychiatric functioning.

RESULTS

No significant group differences were found on neuropsychological measures of speeded attention, verbal memory or visuospatial functions, nor were significant differences observed on computerised measures of response speed, inhibitory control and visuospatial problem solving. Reliable group differences in cognitive performance were observed on tests of executive and intellectual function; performance on these measures was associated with concussion exposure. Group differences were observed for cognitive, affective and behavioural impairment on psychosocial questionnaires and psychiatric diagnoses. There was no evidence of differential effects associated with age in the alumni athletes. Possession of an apolipoprotein ε4 allele was associated with increased endorsement of psychiatric complaints, but not with objective cognitive performance.

CONCLUSIONS

We found only subtle objective cognitive impairment in alumni athletes in the context of high subjective complaints and psychiatric impairment. Apolipoprotein ε4 status related to psychiatric, but not cognitive status. These findings provide benchmarks for the degree of cognitive and behavioural impairment in retired professional athletes and a point of comparison for future neuroimaging and longitudinal studies.

Mild Traumatic Brain Injury: Longitudinal Study of Cognition, Functional Status, and Post-Traumatic Symptoms

More than 75% of traumatic brain injuries (TBIs) seeking medical attention are mild, and outcome in that group is heterogeneous. Until sensitive and valid biomarkers are identified, methods are needed to classify mild TBI into more homogeneous subgroups. Four hundred twenty-one adults with mild TBI were divided into groups based on Glasgow Coma Scale (GCS) 13-15 without computed tomography (CT) abnormalities, GCS 15 with CT abnormalities, and GCS 13-14 with CT abnormalities, and were compared with 120 trauma controls on 1-month and 1-year outcomes. At 1 month post-injury, almost all neuropsychological variables differed significantly among the groups. Compared with trauma controls, the GCS 13-15 CT normal group showed no significant differences on any neuropsychological measure or Glasgow Outcome Scale (GOS). The GCS 15 CT abnormal group performed significantly worse on only a measure of episodic memory and learning (Selective Reminding Recall [SRCL]) and GOS, and the GCS 13-14 CT abnormal group performed significantly worse on most neuropsychological measures and GOS. At 1 year post-injury, except for an isolated difficulty on SRCL in the GCS 13-14 CT abnormal group, no differences were observed on any neuropsychological measures nor on GOS. Mean percent of total post-traumatic symptoms endorsed as new or worse and percent endorsing three or more symptoms differed significantly (p < 0.001), with each TBI subgroup reporting significantly more symptoms than the trauma controls at both 1 month and 1 year. In conclusion, this subgrouping improves granularity within mild TBI. While most neuropsychological and functional differences abate by 1 year, reporting three or more post-traumatic symptoms remain for about half of individuals.

Resting-State Magnetoencephalography Reveals Different Patterns of Aberrant Functional Connectivity in Combat-Related Mild Traumatic Brain Injury

Blast mild traumatic brain injury (mTBI) is a leading cause of sustained impairment in military service members and veterans. However, the mechanism of persistent disability is not fully understood. The present study investigated disturbances in brain functioning in mTBI participants using a source-imaging-based approach to analyze functional connectivity (FC) from resting-state magnetoencephalography (rs-MEG). Study participants included 26 active-duty service members or veterans who had blast mTBI with persistent post-concussive symptoms, and 22 healthy control active-duty service members or veterans. The source time courses from regions of interest (ROIs) were used to compute ROI to whole-brain (ROI-global) FC for different frequency bands using two different measures: 1) time-lagged cross-correlation and 2) phase-lock synchrony. Compared with the controls, blast mTBI participants showed increased ROI-global FC in beta, gamma, and low-frequency bands, but not in the alpha band. Sources of abnormally increased FC included the: 1) prefrontal cortex (right ventromedial prefrontal cortex [vmPFC], right rostral anterior cingulate cortex [rACC]), and left ventrolateral and dorsolateral prefrontal cortex; 2) medial temporal lobe (bilateral parahippocampus, hippocampus, and amygdala); and 3) right putamen and cerebellum. In contrast, the blast mTBI group also showed decreased FC of the right frontal pole. Group differences were highly consistent across the two different FC measures. FC of the left ventrolateral prefrontal cortex correlated with executive functioning and processing speed in mTBI participants. Altogether, our findings of increased and decreased regionalpatterns of FC suggest that disturbances in intrinsic brain connectivity may be the result of multiple mechanisms, and are associated with cognitive sequelae of the injury.

Pumping the Brakes: Neurotrophic Factors for the Prevention of Cognitive Impairment and Dementia after Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of disability and death worldwide, affecting as many as 54,000,000-60,000,000 people annually. TBI is associated with significant impairments in brain function, impacting cognitive, emotional, behavioral, and physical functioning. Although much previous research has focused on the impairment immediately following injury, TBI may have much longer-lasting consequences, including neuropsychiatric disorders and cognitive impairment. TBI, even mild brain injury, has also been recognized as a significant risk factor for the later development of dementia and Alzheimer's disease. Although the link between TBI and dementia is currently unknown, several proposed mechanisms have been put forward, including alterations in glucose metabolism, excitotoxicity, calcium influx, mitochondrial dysfunction, oxidative stress, and neuroinflammation. A treatment for the devastating long-term consequences of TBI is desperately needed. Unfortunately, however, no such treatment is currently available, making this a major area of unmet medical need. Increasing the level of neurotrophic factor expression in key brain areas may be one potential therapeutic strategy. Of the neurotrophic factors, granulocyte-colony stimulating factor (G-CSF) may be particularly effective for preventing the emergence of long-term complications of TBI, including dementia, because of its ability to reduce apoptosis, stimulate neurogenesis, and increase neuroplasticity.

Mild Traumatic Brain Injury

Mild traumatic brain injury (MTBI) is a significant public health problem worldwide. Injured individuals have an increased relative risk of developing a variety of neuropsychiatric conditions associated with the profile of brain regions typically affected in TBI. Within a neurobiopsychosocial framework, this article reviews what is known about the neuropsychiatric sequelae of MTBI, with an emphasis on recent advances.

Practice Update: What Professionals Who Are Not Brain Injury Specialists Need to Know About Intimate Partner Violence-Related Traumatic Brain Injury

There is growing recognition of the risk for traumatic brain injury (TBI) among victims and survivors of intimate partner violence (IPV). A wide range of physically abusive behaviors may lead to injuries to the head or neck and place an individual at risk for a TBI. The purpose of this article is to consolidate current research and present practical guidelines for professionals, who are not brain injury specialists, but work with clients who may have sustained a TBI in the context of IPV. Recommendations are provided for TBI risk screening, making appropriate referrals, and providing services in light of a potential TBI.

Catecholamines and cognition after traumatic brain injury

Cognitive problems are one of the main causes of ongoing disability after traumatic brain injury. The heterogeneity of the injuries sustained and the variability of the resulting cognitive deficits makes treating these problems difficult. Identifying the underlying pathology allows a targeted treatment approach aimed at cognitive enhancement. For example, damage to neuromodulatory neurotransmitter systems is common after traumatic brain injury and is an important cause of cognitive impairment. Here, we discuss the evidence implicating disruption of the catecholamines (dopamine and noradrenaline) and review the efficacy of catecholaminergic drugs in treating post-traumatic brain injury cognitive impairments. The response to these therapies is often variable, a likely consequence of the heterogeneous patterns of injury as well as a non-linear relationship between catecholamine levels and cognitive functions. This individual variability means that measuring the structure and function of a person’s catecholaminergic systems is likely to allow more refined therapy. Advanced structural and molecular imaging techniques offer the potential to identify disruption to the catecholaminergic systems and to provide a direct measure of catecholamine levels. In addition, measures of structural and functional connectivity can be used to identify common patterns of injury and to measure the functioning of brain ‘networks’ that are important for normal cognitive functioning. As the catecholamine systems modulate these cognitive networks, these measures could potentially be used to stratify treatment selection and monitor response to treatment in a more sophisticated manner.

Return to Work and Social Communication Ability Following Severe Traumatic Brain Injury

PURPOSE

Return to competitive employment presents a major challenge to adults who survive traumatic brain injury (TBI). This study was undertaken to better understand factors that shape employment outcome by comparing the communication profiles and self-awareness of communication deficits of adults who return to and maintain employment with those who do not.

METHOD

Forty-six dyads (46 adults with TBI, 46 relatives) were recruited into 2 groups based on the current employment status (employed or unemployed) of participants with TBI. Groups did not differ in regard to sex, age, education, preinjury employment, injury severity, or time postinjury. The La Trobe Communication Questionnaire (Douglas, O'Flaherty, & Snow, 2000) was used to measure communication. Group comparisons on La Trobe Communication Questionnaire scores were analyzed by using mixed 2 × 2 analysis of variance (between factor: employment status; within factor: source of perception).

RESULTS

Analysis yielded a significant group main effect (p = .002) and a significant interaction (p = .004). The employed group reported less frequent difficulties (self and relatives). Consistent with the interaction, unemployed participants perceived themselves to have less frequent difficulties than their relatives perceived, whereas employed participants reported more frequent difficulties than their relatives.

CONCLUSION

Communication outcome and awareness of communication deficits play an important role in reintegration to the workplace following TBI.

Choosing appropriate comparison group participants in studies of veterans: Characteristics of orthopedically injured and uninjured Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn veterans

INTRODUCTION

Research addressing deployment-related traumatic brain injury (TBI) is fairly complex due to a high prevalence of comorbid conditions, multiple exposures, and the lack of acute medical records. Therefore, there is a need for a well-defined, matching comparison group. This study compared deployment-related characteristics, everyday functioning, and cognitive performance in recently deployed veterans who had not sustained any injuries with those who had orthopedic injuries during deployment, but who were without a history of TBI.

METHOD

Participants included 45 individuals who had been deployed and who were without injuries and a group of 27 individuals who reported at least one orthopedic injury during deployment. The Mayo-Portland Adaptability Inventory-4, Community Integration Questionnaire, Veterans RAND 36 Item Health Survey, Brief Pain Inventory, Barratt Impulsiveness Scale-11, and posttraumatic stress disorder (PTSD) Checklist-Civilian (PCL-C) were used to assess daily functioning. Cognitive performance was measured using the Controlled Oral Word Association Test, Trail Making Test, Color-Word Interference Test, and Verbal Selective Reminding Test. The two groups were compared using t tests based on equal variances. The effect size was calculated.

RESULTS

There were no between-group differences, with all variables having p-values >.1 and small to medium effect sizes.

DISCUSSION

Orthopedic injuries sustained during deployment that did not require evacuation or hospitalization did not have any lasting effect on participants' health, cognition, and daily functioning relative to other deployed individuals with no history of injury. These results indicate the two groups are comparable and that their data could be potentially combined to create a single comparison group. Due to the small sample available for this study, the current results are considered preliminary, and further investigation is needed.

FMRI hypoactivation during verbal learning and memory in former high school football players with multiple concussions

Multiple concussions before the age of 18 may be associated with late-life memory deficits. This study examined neural activation associated with verbal encoding and memory retrieval in former athletes ages 40-65 who received at least two concussions (median = 3; range = 2-15) playing high school football and a group of former high school football players with no reported history of concussions matched on age, education, and pre-morbid IQ. Functional magnetic resonance imaging data collected during a modified verbal paired associates paradigm indicated that those with concussive histories had hypoactivation in left hemispheric language regions, including the inferior/middle frontal gyri and angular gyrus compared with controls. However, concussive history was not associated with worse memory functioning on neuropsychological tests or worse behavioral performance during the paradigm, suggesting that multiple early-life concussions may be associated with subtle changes in the verbal encoding system that limits one from accessing higher-order semantic networks, but this difference does not translate into measurable cognitive performance deficits.

A Systematic Review of the Efficacy of Community-based, Leisure/Social Activity Programmes for People with Traumatic Brain Injury

Background: Many people who have a severe traumatic brain injury (TBI) are not able to resume employment and consequently experience profound changes in their lifestyle. They have increased amounts of ’spare time’ yet often find it difficult to engage in meaningful activity. Leisure activities are one way in which meaningful activity can be increased.

Aims: This systematic review has two purposes: first, to identify and evaluate the efficacy of community-based interventions for leisure/social activity after TBI, and second to provide details on the types of intervention.

Method: Systematic searches were conducted of Medline, PsycINFO and PsycBITE to October 2014, as well as hand searches of two occupational therapy journals. Inclusion criteria were as follows: peer reviewed journal articles on adults with TBI who had participated in a trial evaluating a community-based intervention specifically targeting leisure/social activity. All research methodologies using primary studies that provided empirical, quantitative data were considered. Scientific quality of the studies was evaluated using the PEDro Scale for controlled trials and the Risk of Bias in N-of-1 Trials Scale for single-case designs.

Results: Two independent raters screened 196 abstracts, resulting in nine articles that met selection criteria. Data were then independently extracted by the raters. Four of the nine studies used a control condition in their research design (two randomised controlled trials, one controlled but non-randomised study, and one single-case experiment using a changing criterion design). Two of the studies conducted between-group analyses with significant treatment effects for mood and quality of life using active leisure programmes (Tai Chi Qigong and a combined programme of outdoor adventure experiences and goal setting respectively). Intervention programmes identified in the review were then grouped and described according to the approach or model used, including active leisure programmes, social peer mentoring, individual brokered leisure services and a therapeutic recreation model. Additional intervention models and approaches that did not result directly from the systematic review were also described because they provide information on the current approaches used in practice (Clubhouse model and leisure education programmes in the stroke population).

Conclusions: There is some evidence for the effectiveness of community-based interventions for leisure/social activity for people who have had a TBI to improve mood and quality of life. The conclusions of this review are that the interventions for this area need to be planned and specific, structured and goal-driven, intensive and conducted over a period of months.

Post-traumatic stress disorder and traumatic brain injury

Disentangling the effects of "organic" neurologic damage and psychological distress after a traumatic brain injury poses a significant challenge to researchers and clinicians. Establishing a link between traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) has been particularly contentious, reflecting difficulties in establishing a unique diagnosis for conditions with overlapping and sometimes contradictory symptom profiles. However, each disorder is linked to a variety of adverse health outcomes, underscoring the need to better understand how neurologic and psychiatric risk factors interact following trauma. Here, we present data showing that individuals with a TBI are more likely to develop PTSD, and that individuals with PTSD are more likely to develop persistent cognitive sequelae related to TBI. Further, we describe neurobiological models of PTSD, highlighting how patterns of neurologic damage typical in TBI may promote or protect against the development of PTSD in brain-injured populations. These data highlight the unique course of PTSD following a TBI and have important diagnostic, prognostic, and treatment implications for individuals with a dual diagnosis.

Predicting institutionalization after traumatic brain injury inpatient rehabilitation

Risk factors contributing to institutionalization after inpatient rehabilitation for people with traumatic brain injury (TBI) have not been well studied and need to be better understood to guide clinicians during rehabilitation. We aimed to develop a prognostic model that could be used at admission to inpatient rehabilitation facilities to predict discharge disposition. The model could be used to provide the interdisciplinary team with information regarding aspects of patients' functioning and/or their living situation that need particular attention during inpatient rehabilitation if institutionalization is to be avoided. The study population included 7219 patients with moderate-severe TBI in the Traumatic Brain Injury Model Systems (TBIMS) National Database enrolled from 2002-2012 who had not been institutionalized prior to injury. Based on institutionalization predictors in other populations, we hypothesized that among people who had lived at a private residence prior to injury, greater dependence in locomotion, bed-chair-wheelchair transfers, bladder and bowel continence, feeding, and comprehension at admission to inpatient rehabilitation programs would predict institutionalization at discharge. Logistic regression was used, with adjustment for demographic factors, proxy measures for TBI severity, and acute-care length-of-stay. C-statistic and predictiveness curves validated a five-variable model. Higher levels of independence in bladder management (adjusted odds ratio [OR], 0.88; 95% CI 0.83, 0.93), bed-chair-wheelchair transfers (OR, 0.81 [95% CI, 0.83-0.93]), and comprehension (OR, 0.78 [95% CI, 0.68, 0.89]) at admission were associated with lower risks of institutionalization on discharge. For every 10-year increment in age was associated with a 1.38 times higher risk for institutionalization (95% CI, 1.29, 1.48) and living alone was associated with a 2.34 times higher risk (95% CI, 1.86, 2.94). The c-statistic was 0.780. We conclude that this simple model can predict risk of institutionalization after inpatient rehabilitation for patients with TBI.

Voxel-wise resting-state MEG source magnitude imaging study reveals neurocircuitry abnormality in active-duty service members and veterans with PTSD

Post-traumatic stress disorder (PTSD) is a leading cause of sustained impairment, distress, and poor quality of life in military personnel, veterans, and civilians. Indirect functional neuroimaging studies using PET or fMRI with fear-related stimuli support a PTSD neurocircuitry model that includes amygdala, hippocampus, and ventromedial prefrontal cortex (vmPFC). However, it is not clear if this model can fully account for PTSD abnormalities detected directly by electromagnetic-based source imaging techniques in resting-state. The present study examined resting-state magnetoencephalography (MEG) signals in 25 active-duty service members and veterans with PTSD and 30 healthy volunteers. In contrast to the healthy volunteers, individuals with PTSD showed: 1) hyperactivity from amygdala, hippocampus, posterolateral orbitofrontal cortex (OFC), dorsomedial prefrontal cortex (dmPFC), and insular cortex in high-frequency (i.e., beta, gamma, and high-gamma) bands; 2) hypoactivity from vmPFC, Frontal Pole (FP), and dorsolateral prefrontal cortex (dlPFC) in high-frequency bands; 3) extensive hypoactivity from dlPFC, FP, anterior temporal lobes, precuneous cortex, and sensorimotor cortex in alpha and low-frequency bands; and 4) in individuals with PTSD, MEG activity in the left amygdala and posterolateral OFC correlated positively with PTSD symptom scores, whereas MEG activity in vmPFC and precuneous correlated negatively with symptom score. The present study showed that MEG source imaging technique revealed new abnormalities in the resting-state electromagnetic signals from the PTSD neurocircuitry. Particularly, posterolateral OFC and precuneous may play important roles in the PTSD neurocircuitry model.

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Resting-state MEG detects abnormal electromagnetic activity in PTSD neurocircuitry

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PTSD showed hyperactivity in amygdala, hippocampus, and orbitofrontal cortex

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PTSD showed hypoactivity in vmPFC, frontal pole, and dlPFC

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PTSD symptom score correlated with MEG activity

Single-subject-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mild traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild TBI (mTBI) can be difficult to detect using conventional MRI or CT. Injured brain tissues in mTBI patients generate abnormal slow-waves (1–4 Hz) that can be measured and localized by resting-state magnetoencephalography (MEG). In this study, we develop a voxel-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mTBI on a single-subject basis. A normative database of resting-state MEG source magnitude images (1–4 Hz) from 79 healthy control subjects was established for all brain voxels. The high-resolution MEG source magnitude images were obtained by our recent Fast-VESTAL method. In 84 mTBI patients with persistent post-concussive symptoms (36 from blasts, and 48 from non-blast causes), our method detected abnormalities at the positive detection rates of 84.5%, 86.1%, and 83.3% for the combined (blast-induced plus with non-blast causes), blast, and non-blast mTBI groups, respectively. We found that prefrontal, posterior parietal, inferior temporal, hippocampus, and cerebella areas were particularly vulnerable to head trauma. The result also showed that MEG slow-wave generation in prefrontal areas positively correlated with personality change, trouble concentrating, affective lability, and depression symptoms. Discussion is provided regarding the neuronal mechanisms of MEG slow-wave generation due to deafferentation caused by axonal injury and/or blockages/limitations of cholinergic transmission in TBI. This study provides an effective way for using MEG slow-wave source imaging to localize affected areas and supports MEG as a tool for assisting the diagnosis of mTBI.

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A voxel-based whole-brain MEG slow-wave source imaging method for mild TBI.

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The new approach showed 84.5% positive detection rate in 84 mild TBI patients.

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The new approach detected loci of injury in mild TBI patients on a single-subject basis.

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MEG slow-wave source imaging revealed brain areas vulnerable to mild TBI.

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MEG slow-wave generations correlated with mild TBI symptoms.

Sustained outcomes following mild traumatic brain injury: results of a five-emergency department longitudinal study

OBJECTIVE

To report on the occurrence of sustained outcomes including post-concussion symptoms, health services used and indicators of social disruption following a mild traumatic brain injury (MTBI).

RESEARCH DESIGN

A dual cohort comparing MTBI Emergency Department (ED) patients and a comparison group of non-head injured ED patients.

METHODS AND PROCEDURES

The outcomes measures employed were the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and indicators of health services used and social disruption all recorded at the ED and at 3 and 6 months post-ED discharge. 'Sustained' meant a positive response to these measures at 3 and 6 months.

MAIN OUTCOMES AND RESULTS

Reasonable follow-up success was achieved at 3 and 6 months and the cohorts were alike on all demographic descriptors. RPQ average score and symptom occurrence were far more frequent among MTBI patients than for the comparison cohort from 3 to 6 months. The use of health services and indicators of social disruption were also more frequent among MTBI post-discharge patients.

CONCLUSIONS

These findings argue that some with an MTBI suffer real complaints and they are sustained from 3 to at least 6 months. More effort should be given toward specificity of these symptoms from those reported by members of the comparison group.

Prehospital risk factors of mortality and impaired consciousness after severe traumatic brain injury: an epidemiological study

Background

Severe traumatic brain injury (TBI) is a significant health concern and a major burden for society. The period between trauma event and hospital admission in an emergency department (ED) could be a determinant for secondary brain injury and early survival. The aim was to investigate the relationship between prehospital factors associated with secondary brain injury (arterial hypotension, hypoxemia, hypothermia) and the outcomes of mortality and impaired consciousness of survivors at 14 days.

Methods

A multicenter, prospective cohort study was performed in dedicated trauma centres of Switzerland. Adults with severe TBI (Abbreviated Injury Scale score of head region (HAIS) >3) were included. Main outcome measures were death and impaired consciousness (Glasgow Coma Scale (GCS) ≤13) at 14 days. The associations between risk factors and outcome were assessed with univariate and multivariate regression models.

Results

589 patients were included, median age was 55 years (IQR 33, 70). The median GCS in ED was 4 (IQR 3-14), with abnormal pupil reaction in 167 patients (29.2%). Median ISS was 25 (IQR 21, 34). Three hundred seven patients sustained their TBI from falls (52.1%) and 190 from a road traffic accidents (32.3%). Median time from Out-of-hospital Emergency Medical Service (OHEMS) departure on scene to arrival in ED was 50 minutes (IQR 37-72); 451 patients had a direct admission (76.6%). Prehospital hypotension was observed in 24 (4.1%) patients, hypoxemia in 73 (12.6%) patients and hypothermia in 146 (24.8%). Prehospital hypotension and hypothermia (apart of age and trauma severity) was associated with mortality. Prehospital hypoxemia (apart of trauma severity) was associated with impaired consciousness; indirect admission was a protective factor.

Conclusion

Mortality and impaired consciousness at 14 days do not have the same prehospital risk factors; prehospital hypotension and hypothermia is associated with mortality, and prehospital hypoxemia with impaired consciousness.

Traumatic brain injury and chronic traumatic encephalopathy: a forensic neuropsychiatric perspective

Recent scientific reports and popular press describing chronic traumatic encephalopathy (CTE) collectively link this condition to a broad array of neuropsychiatric symptoms, including extremely rare and multi-determined behaviors such as murder-suicide. These reports are difficult to reconcile with several decades of research on the science of traumatic brain injury (TBI) and its consequences, especially the natural history and prognosis of mild TBI. This article attempts to reconcile these sources by reviewing the state of the science on CTE, with particular attention to case definitions and neuropathological criteria for this diagnosis. The evidence for links between TBI, CTE, and catastrophic clinical events is explored, and the complexity of attributing rare frequency behavioral events to CTE is highlighted. The clinical and medicolegal implications of the best available evidence are discussed, concluding with a cautionary note against prematurely generalizing current findings on CTE to entire populations of persons with, or at risk for, concussion exposures.

Health-related quality of life in traumatic brain injury: is a proxy report necessary?

Despite its importance to care, clinicians and researchers often discount patient-reported outcomes in favor of proxy reports, in persons with traumatic brain injury (TBI). The rationale relates to concerns about lack of awareness of patients regarding their functioning. However, although lack of awareness occurs in some patients with severe TBI, or in TBI involving certain lesion locations, or very soon after injury, this conclusion has been overgeneralized. The objective of this study is to determine the validity of patient-reported health-related quality of life by evaluating its relationship to injury severity and more objective indices of outcome, in a representative series of adults with TBI. A consecutive sample of 374 persons with TBI at least 14 years old, and having a post-resuscitation Glasgow Coma Scale score ≤12, an acute seizure, or a CT scan showing TBI- related findings. Seventy-six percent (374/491) of the eligible survivors were assessed at 6 months post-injury on the Life Satisfaction Survey. The greatest decrease in satisfaction was in the ability to think and remember, work, receive adequate income, and participate in leisure and recreational activities. Dissatisfaction significantly related to the functional limitation in that area as judged by the patients themselves (p<0.001) or by someone who knew them well (p≤0.001). The most severely injured group reported the most dissatisfaction for 13 out of 17 areas assessed. Patients with TBI, in general, do not need a proxy to report on their behalf regarding their functional limitations or health-related quality of life.

Community versus orthopaedic controls in traumatic brain injury research: how comparable are they?

BACKGROUND

Community (CC) or orthopaedic/injury (OC) control groups are typically used to evaluate the consequences of traumatic brain injuries (TBIs). Whereas CCs match for demographic variables and are readily available, OCs may additionally control for other pre- and post-injury variables but are more costly to recruit. Together, they enable an evaluation of brain- vs general-injury effects. However, the comparability of these two groups and the increase in control over confounding variables when OCs are used has rarely been examined.

METHOD

The current study compared samples of CCs (n = 71) and OCs (n = 69), aged between 18-80, on a range of demographic (age, gender, education, socio-economic status), background (medical history, handedness), psychosocial (alcohol use, fatigue, pain, depression, social support, community integration, 'post-concussion' symptoms) and cognitive (motor and processing speed, memory, intellectual ability) variables.

RESULTS

The two groups were comparable on all variables, except alcohol use, with the OC group having higher levels of alcohol consumption. However, alcohol use did not correlate with any other variable, including commonly used measures of outcome following TBI.

CONCLUSION

The current findings suggest that an orthopaedic injury control group does not have any clear advantages over a carefully recruited community control group.

Premorbid personality characteristics and attachment style moderate the effect of injury severity on occupational outcome in traumatic brain injury: another aspect of reserve

The concept of "reserve" has been proposed to account for the mismatch between brain pathology and its clinical expression. Prior efforts to characterize this concept focused mostly on brain or cognitive reserve measures. The present study was a preliminary attempt to evaluate premorbid personality and emotional aspects as potential moderators in moderate-to-severe traumatic brain injury. Using structural equation modeling and multiple regression analyses, we found that premorbid personality characteristics provided the most robust moderator of injury severity on occupational outcome. Findings offer preliminary support for premorbid personality features as another relevant reserve construct in predicting outcome in this population.

Traumatic brain injury and post-acute decline: what role does environmental enrichment play? A scoping review

Objectives: While a growing number of studies provide evidence of neural and cognitive decline in traumatic brain injury (TBI) survivors during the post-acute stages of injury, there is limited research as of yet on environmental factors that may influence this decline. The purposes of this paper, therefore, are to (1) examine evidence that environmental enrichment (EE) can influence long-term outcome following TBI, and (2) examine the nature of post-acute environments, whether they vary in degree of EE, and what impact these variations have on outcomes.

Methods: We conducted a scoping review to identify studies on EE in animals and humans, and post-discharge experiences that relate to barriers to recovery.

Results: One hundred and twenty-three articles that met inclusion criteria demonstrated the benefits of EE on brain and behavior in healthy and brain-injured animals and humans. Nineteen papers on post-discharge experiences revealed that variables such as insurance coverage, financial, and social support, home therapy, and transition from hospital to home, can have an impact on clinical outcomes.

Conclusion: There is evidence to suggest that lack of EE, whether from lack of resources or limited ability to engage in such environments, may play a role in post-acute cognitive and neural decline. Maximizing EE in the post-acute stages of TBI may improve long-term outcomes for the individual, their family and society.

Lack of long-term fMRI differences after multiple sports-related concussions

INTRODUCTION

Mild traumatic brain injury (mTBI) or concussion has been acutely associated with several cognitive symptoms, including deficits in response inhibition, working memory and motor performance. The pervasiveness of these cognitive symptoms has been more controversial. The effects of multiple concussions on neuropsychological functioning and brain activation following at least 6-months post-mTBI were examined.

METHODS

Twenty right-handed male athletes with a history of at least two concussions and 20 age/pre-morbid IQ/athletic-experience matched controls underwent neuropsychological assessment and fMRI scanning where they performed versions of a colour-word Stroop interference task, an operation-span working memory task and a finger-tapping task.

RESULTS

The Attention index score on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was lower for the concussion group, but only at liberal statistical threshold. Total RBANS score approached statistical significance. Reaction time during neurobehavioural tasks was similar across groups, but accuracy was reduced in the concussed group on the working memory task. Despite expected activation patterns within each group, there were no group differences in neural activation on any functional tasks using either whole-brain or ROI-specific analyses at liberal statistical thresholds.

CONCLUSION

There were minimal differences between the two closely matched groups. Results point to the relative plasticity of younger adults' cognitive abilities following concussion.

Mild traumatic brain injury in translation

This Introduction to a Special Issue on Mild Traumatic Brain Injury (mTBI) highlights the methodological challenges in outcome studies and clinical trials involving patients who sustain mTBI. Recent advances in brain imaging and portable, computerized cognitive tasks have contributed to protocols that are sensitive to the effects of mTBI and efficient in time for completion. Investigation of civilian mTBI has been extended to single and repeated injuries in athletes and blast-related mTBI in service members and veterans. Despite differences in mechanism of injury, there is evidence for similar effects of acceleration-deceleration and blast mechanisms of mTBI on cognition. Investigation of repetitive mTBI suggests that the effects may be cumulative and that repeated mTBI and repeated subconcussive head trauma may lead to neurodegenerative conditions. Although animal models of mTBI using cortical impact and fluid percussion injury in rodents have been able to reproduce some of the cognitive deficits frequently exhibited by patients after mTBI, modeling post-concussion symptoms is difficult. Recent use of closed head and blast injury animal models may more closely approximate clinical mTBI. Translation of interventions that are developed in animal models to patients with mTBI is a priority for the research agenda. This Special Issue on mTBI integrates basic neuroscience studies using animal models with studies of human mTBI, including the cognitive sequelae, persisting symptoms, brain imaging, and host factors that facilitate recovery.

Virtual reality as a screening tool for sports concussion in adolescents

PRIMARY OBJECTIVE

There is controversy surrounding the cognitive effects of sports concussion. This study aimed to verify whether the technique of virtual reality could aid in the identification of attention and inhibition deficits in adolescents.

STUDY DESIGN

A prospective design was used to assess 25 sports-concussed and 25 non-sports-concussed adolescents enrolled in a sport and education programme.

METHODS AND PROCEDURES

Participants were evaluated in immersive virtual reality via ClinicaVR: Classroom-CPT and in real life via the traditional VIGIL-CPT.

MAIN OUTCOMES AND RESULTS

The neuropsychological assessment using virtual reality showed greater sensitivity to the subtle effects of sports concussion compared to the traditional test, which showed no difference between groups. The results also demonstrated that the sports concussion group reported more symptoms of cybersickness and more intense cybersickness than the control group.

CONCLUSIONS

Sports concussion was associated with subtle deficits in attention and inhibition. However, further studies are needed to support these results.

An automatic MEG low-frequency source imaging approach for detecting injuries in mild and moderate TBI patients with blast and non-blast causes

Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild (and some moderate) TBI can be difficult to diagnose because the injuries are often not detectable on conventional MRI or CT. Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (ALFMA, peaked at 1-4 Hz) that can be measured and localized by magnetoencephalography (MEG). We developed a new automated MEG low-frequency source imaging method and applied this method in 45 mild TBI (23 from combat-related blasts, and 22 from non-blast causes) and 10 moderate TBI patients (non-blast causes). Seventeen of the patients with mild TBI from blasts had tertiary injuries resulting from the blast. The results show our method detected abnormalities at the rates of 87% for the mild TBI group (blast-induced plus non-blast causes) and 100% for the moderate group. Among the mild TBI patients, the rates of abnormalities were 96% and 77% for the blast and non-blast TBI groups, respectively. The spatial characteristics of abnormal slow-wave generation measured by Z scores in the mild blast TBI group significantly correlated with those in non-blast mild TBI group. Among 96 cortical regions, the likelihood of abnormal slow-wave generation was less in the mild TBI patients with blast than in the mild non-blast TBI patients, suggesting possible protective effects due to the military helmet and armor. Finally, the number of cortical regions that generated abnormal slow-waves correlated significantly with the total post-concussive symptom scores in TBI patients. This study provides a foundation for using MEG low-frequency source imaging to support the clinical diagnosis of TBI.

Recovery of Impairments After Severe Traumatic Brain Injury: Findings From a Prospective, Multicentre Study

This study aimed to describe the recovery of impairments after severe traumatic brain injury (TBI) over a 3-year period. An inception cohort over 2 years was recruited from 11 brain injury rehabilitation units participating in a state-wide program. The 131 individuals with TBI were assessed at admission to the rehabilitation program, 18 months and 3 years post-trauma. This report described results from the Disability Rating Scale (DRS) and Mayo-Portland Adaptability Index (MPAI). Regression analyses, examining the influence of five acute injury variables on DRS and MPAI, revealed that posttraumatic amnesia (PTA) was a significant individual predictor. Data were thus analysed according to duration of PTA: 1 to 2 weeks (n= 19), 2 to 4 weeks (n= 44) and more than 4 weeks (n= 68). At program admission there was poorer overall level of functioning on the DRS in the longest PTA group, but no difference between the shorter PTA groups. Significant improvements occurred on the DRS for all PTA groups over the first 18 months posttrauma, with improvements continuing between 18 months and 3 years. At the 3-year follow-up, frequency data from the MPAI indicated that clinically significant impairments in mobility, hand function, communication and behaviour were uncommon in the shorter PTA groups, although 36% to 47% continued to experience cognitive impairments. Impairments were common in the longest PTA group in some areas, particularly cognition where two thirds or more continued to experience clinically significant impairments in attention, memory and novel problem-solving. These results confirm the predictive significance of PTA duration regarding longer-term level of recovery. They also highlight the limitation in classifying the ‘severe’ TBI category as an homogenous group: significant subgroup differences occurred on medical and functional variables at program admission, 18 months and 3 years posttrauma. These data further substantiate the persistence of neuropsychological impairments in the face of good physical recovery at all levels of severity within the severe TBI group.

Reconstruction of Identity After Brain Injury

Following severe traumatic brain injury, difficulty with behavioural adjustment and community reintegration is common. A potential contributor to this difficulty is a sense of personal identity that is inconsistent with the restrictions on activity and need for effortful compensation imposed by persistent impairment. We summarise an information processing framework within which the impact of schematic mental models of self is explained and present intervention procedures designed to help individuals with traumatic brain injury reconstruct an organised and positive sense of personal identity. We conclude the paper with three instructive case illustrations.