Chronic Effects of Boxing: Diffusion Tensor Imaging and Cognitive Findings

We used magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to evaluate the effects of boxing on brain structure and cognition in 10 boxers (8 retired, 2 active; mean age = 45.7 years; standard deviation [SD] = 9.71) and 9 participants (mean age = 43.44; SD = 9.11) in noncombative sports. Evans Index (maximum width of the anterior horns of the lateral ventricles/maximal width of the internal diameter of the skull) was significantly larger in the boxers (F = 4.52; p = 0.050; Cohen's f = 0.531). Word list recall was impaired in the boxers (F(1,14) = 10.70; p = 0.006; f = 0.84), whereas implicit memory measured by faster reaction time (RT) to a repeating sequence of numbers than to a random sequence was preserved (t = 2.52; p < 0.04). Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) measured by tractography did not significantly differ between groups. However, DTI metrics were significantly correlated with declarative memory (e.g., left ventral striatum ADC with delayed recall, r = -0.74; p = 0.02) and with RT to the repeating number sequence (r = 0.70; p = 0.04) in the boxers. Years of boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r = -0.74; p = 0.02), delayed recall (r = -0.83; p = 0.003), and serial RT (r = 0.66; p = 0.05). We conclude that microstructural integrity of white matter tracts is related to declarative memory and response speed in boxers and to the extent of boxing exposure. Implications for chronic traumatic encephalopathy are discussed.

White matter structural connectivity changes correlate with epilepsy duration in temporal lobe epilepsy

PURPOSE

Temporal lobe epilepsy (TLE) is thought to be a network disease and structural changes using diffusion tensor imaging (DTI) have been shown. However, lateralized differences in the structural integrity of TLE, as well as changes in structural integrity with longer disease duration, have not been well defined.

METHODS

We examined the fractional anisotropy (FA) and mean diffusivity (MD) in the hippocampus, as well as its primary (cingulum and fornix) and remote (uncinate and external capsule) connections in both right and left TLE. Changes in diffusion measures over the disease course were examined by correlating FA and MD in the various structures with epilepsy duration. The potential for each measure of anisotropy and diffusivity as a marker of TLE laterality was investigated using random forest (RF) analysis.

RESULTS

MD was increased in the bilateral hippocampus, cingulum, fornix and the right external capsule in both left and right TLE compared to controls. In addition, left TLE exhibited an increased MD in the ipsilateral uncinate fasciculus and bilateral external capsules. A decrease in FA was seen in the left cingulum in left TLE. RF analysis demonstrated that MD of the right hippocampus and FA of the left external capsule were important predictors of TLE laterality. An association of increased MD with epilepsy duration was seen in the left hippocampus in left TLE.

CONCLUSION

Evidence of disrupted white matter architecture in the hippocampus and its primary and remote connections were demonstrated in TLE. While changes in the hippocampus and cingulum were more prominent in right TLE, remote changes were more prominent in left TLE. MD of the right hippocampus and FA of the left external capsule were found to be the strongest structural predictors of TLE laterality. Changes associated with duration of epilepsy indicated that changes in structural integrity may be progressive over the disease course. This study illustrates the potential of structural diffusion tensor imaging in elucidating pathophysiology, enhancing diagnosis and assisting prognostication.

Prevalence and Predictors of Poor Recovery from Mild Traumatic Brain Injury

Although most patients with mild traumatic brain injury (mTBI) recover within 3 months, a subgroup of patients experience persistent symptoms. Yet, the prevalence and predictors of persistent dysfunction in patients with mTBI remain poorly understood. In a longitudinal study, we evaluated predictors of symptomatic and cognitive dysfunction in adolescents and young adults with mTBI, compared with two control groups-patients with orthopedic injuries and healthy uninjured individuals. Outcomes were assessed at 3 months post-injury. Poor symptomatic outcome was defined as exhibiting a symptom score higher than 90% of the orthopedic control (OC) group, and poor cognitive outcome was defined as exhibiting cognitive performance poorer than 90% of the OC group. At 3 months post-injury, more than half of the patients with mTBI (52%) exhibited persistently elevated symptoms, and more than a third (36.4%) exhibited poor cognitive outcome. The rate of high symptom report in mTBI was markedly greater than that of typically developing (13%) and OC (17%) groups; the proportion of those with poor cognitive performance in the mTBI group exceeded that of typically developing controls (15.8%), but was similar to that of the OC group (34.9%). Older age at injury, female sex, and acute symptom report were predictors of poor symptomatic outcome at 3 months. Socioeconomic status was the only significant predictor of poor cognitive outcome at 3 months.

Disruption of caudate working memory activation in chronic blast-related traumatic brain injury

Mild to moderate traumatic brain injury (TBI) due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes). Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI) study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female) who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females) with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females) and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females) without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate). Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results could not be attributed to caudate atrophy or the presence of PTSD symptoms. Our results point to a specific vulnerability of the caudate to blast injury. Changes in activation during the Sternberg Item Recognition Task, and potentially other tasks that recruit the caudate, may serve as biomarkers for blast TBI.

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We investigated whether fMRI would discriminate blunt-force from blast mTBI.

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We used a working memory task with varying numbers of letters (set sizes).

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Blunt-force TBI showed a monotonic relation between set size and caudate activation.

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This relation was disrupted in the blast TBI group.

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Results point to a specific vulnerability of the caudate to blast injury

Diagnosis, prognosis, and clinical management of mild traumatic brain injury

Concussion and mild traumatic brain injury (TBI) are interchangeable terms to describe a common disorder with substantial effects on public health. Advances in brain imaging, non-imaging biomarkers, and neuropathology during the past 15 years have required researchers, clinicians, and policy makers to revise their views about mild TBI as a fully reversible insult that can be repeated without consequences. These advances have led to guidelines on management of mild TBI in civilians, military personnel, and athletes, but their widespread dissemination to clinical management in emergency departments and community-based health care is still needed. The absence of unity on the definition of mild TBI, the scarcity of prospective data concerning the long-term effects of repeated mild TBI and subconcussive impacts, and the need to further develop evidence-based interventions to mitigate the long-term sequelae are areas for future research that will improve outcomes, reduce morbidity and costs, and alleviate delayed consequences that have only recently come to light.

Brain Graph Topology Changes Associated with Anti-Epileptic Drug Use

Neuroimaging studies of functional connectivity using graph theory have furthered our understanding of the network structure in temporal lobe epilepsy (TLE). Brain network effects of anti-epileptic drugs could influence such studies, but have not been systematically studied. Resting-state functional MRI was analyzed in 25 patients with TLE using graph theory analysis. Patients were divided into two groups based on anti-epileptic medication use: those taking carbamazepine/oxcarbazepine (CBZ/OXC) (n=9) and those not taking CBZ/OXC (n=16) as a part of their medication regimen. The following graph topology metrics were analyzed: global efficiency, betweenness centrality (BC), clustering coefficient, and small-world index. Multiple linear regression was used to examine the association of CBZ/OXC with graph topology. The two groups did not differ from each other based on epilepsy characteristics. Use of CBZ/OXC was associated with a lower BC. Longer epilepsy duration was also associated with a lower BC. These findings can inform graph theory-based studies in patients with TLE. The changes observed are discussed in relation to the anti-epileptic mechanism of action and adverse effects of CBZ/OXC.

Anxiety disorders in children and adolescents in the second six months after traumatic brain injury

The objective of this prospective longitudinal study was to assess the nature, rate, predictive variables, and neuroimaging characteristics of novel (new-onset) anxiety disorders (compared with no novel anxiety disorders) 6-12 months after pediatric traumatic brain injury (TBI). Psychiatric and psychosocial interviews were administered to children who sustained mild to severe TBI at baseline (soon after injury) and at the 12-month follow-up post-injury (n= 125). The psychiatric outcome of children 12-months post-injury revealed that novel anxiety disorders present in the second six months after TBI were heterogeneous and occurred in 13 (10.4%) participants. Novel anxiety disorder was significantly associated with concurrent novel depressive disorder and with novel personality change due to TBI. Novel anxiety disorder was marginally associated with younger age at injury and with pre-injury anxiety disorder in univariate analyses. Age at injury, pre-injury anxiety disorder, and personality change due to TBI were each significantly and independently related to novel anxiety disorder in a logistic regression analysis. There were no significant neuroimaging group differences. These findings suggest that the emergence of novel anxiety disorder after TBI might be related to a broader problem of affective dysregulation especially in younger children and those with a vulnerability even to pre-injury anxiety disorder.

Traumatic brain injury and cognition

Traumatic brain injury (TBI) is a major cause of death and disability, and therefore an important health and socioeconomic problem for our society. Individuals surviving from a moderate to severe TBI frequently suffer from long-lasting cognitive deficits. Such deficits include different aspects of cognition such as memory, attention, executive functions, and awareness of their deficits. This chapter presents a review of the main neuropsychological and neuroimaging studies of patients with TBI. These studies found that patients evolve differently according to the severity of the injury, the mechanism causing the injury, and the lesion location. Further research is necessary to develop rehabilitation methods that enhance brain plasticity and recovery after TBI. In this chapter, we summarize current knowledge and controversies, focusing on cognitive sequelae after TBI. Recommendations from the Common Data Elements are provided, with an emphasis on diagnosis, outcome measures, and studies organization to make data more comparable across studies. Final considerations on neuroimaging advances, rehabilitation approaches, and genetics are described in the final section of the chapter.

Psychiatric disorders in children and adolescents 24 months after mild traumatic brain injury

This study aimed to better understand the occurrence of novel psychiatric disorders (NPDs) in children with mild traumatic brain injury (mTBI) in relation to preinjury variables, injury-related variables, and concurrent neurocognitive outcome. Eighty-seven children aged 5-14 years who had experienced mTBI were studied from consecutive hospital admissions with semistructured psychiatric interviews soon after injury (baseline). Fifty-four children were reassessed 24 months postinjury. Standardized instruments were used to evaluate injury severity, lesion characteristics, preinjury variables (lifetime psychiatric disorder, family psychiatric history, family function, socioeconomic status, psychosocial adversity, adaptive function, and academic function), and finally, postinjury neurocognitive and adaptive function. At 24 months postinjury, NPDs had occurred in 17 of 54 (31%) participants. NPD at 24 months was related to frontal white matter lesions and was associated with estimated preinjury reading, preinjury adaptive function, and concurrent deficits in reading, processing speed, and adaptive function. These findings extend earlier reports that the psychiatric morbidity after mTBI in children is more common than previously thought, and moreover, it is linked to preinjury individual variables and injury characteristics and is associated with postinjury adaptive and neurocognitive functioning.

Personality Change Due to Traumatic Brain Injury in Children and Adolescents: Neurocognitive Correlates

Personality change due to traumatic brain injury (PC) in children is an important psychiatric complication of injury and is a form of severe affective dysregulation. This study aimed to examine neurocognitive correlates of PC. The sample included 177 children 5-14 years old with traumatic brain injury who were enrolled from consecutive admissions to five trauma centers. Patients were followed up prospectively at baseline and at 6 months, and they were assessed with semistructured psychiatric interviews. Injury severity, socioeconomic status, and neurocognitive function (measures of attention, processing speed, verbal memory, IQ, verbal working memory, executive function, naming/reading, expressive language, motor speed, and motor inhibition) were assessed with standardized instruments. Unremitted PC was present in 26 (18%) of 141 participants assessed at 6 months postinjury. Attention, processing speed, verbal memory, IQ, and executive function were significantly associated with PC even after socioeconomic status, injury severity, and preinjury attention deficit hyperactivity disorder were controlled. These findings are a first step in characterizing concomitant cognitive impairments associated with PC. The results have implications beyond brain injury to potentially elucidate the neurocognitive symptom complex associated with mood instability regardless of etiology.

Effect of clinical characteristics on cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury

OBJECTIVE

To examine the relationship between clinical characteristics and cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury (mTBI).

DESIGN

This study consisted of 40 Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) service members and veterans; 20 participants reported blast exposure and alteration of mental status consistent with mTBI and 20 participants denied blast exposure and had no history of traumatic brain injury (TBI), but could have experienced extra-cranial injuries. Measures of simple reaction time, processing speed, visual attention, working memory and mathematical processing were used to assess long-term effects of mTBI. Measures of post-traumatic stress symptom severity, pain intensity, sleep difficulty and subjective appraisal of cognition at time of testing were also obtained. Multivariate analyses were conducted with clinical characteristics and mTBI history as predictors of cognitive performance.

RESULTS

There was no evidence of an effect of mTBI history on cognitive performance in this sample. However, post-traumatic stress symptom severity was significantly related to two measures of cognitive performance.

CONCLUSIONS

This study demonstrated the importance of considering the effects of current clinical symptoms (e.g. post-traumatic stress) as possibly having greater influence on current cognitive functioning than the effects of a remote history of mTBI.

Emotional prosody and diffusion tensor imaging in children after traumatic brain injury

PRIMARY OBJECTIVE

Brain structures and their white matter connections that may contribute to emotion processing and may be vulnerable to disruption by a traumatic brain injury (TBI) occurring in childhood have not been thoroughly explored.

RESEARCH DESIGN AND METHODS

The current investigation examines the relationship between diffusion tensor imaging (DTI) metrics, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), and 3-month post-injury performance on a task of emotion prosody recognition and a control task of phonological discrimination in a group of 91 children who sustained either a moderate-to-severe TBI (n = 45) or orthopaedic injury (OI) (n = 46).

MAIN OUTCOMES AND RESULTS

Brain-behaviour findings within OI participants confirmed relationships between several significant white matter tracts in emotional prosody performance (i.e. the cingulum bundle, genu of the corpus callosum, inferior longitudinal fasciculus (ILF) and the inferior fronto-occipital fasciculus (IFOF). The cingulum and genu were also related to phonological discrimination performance. The TBI group demonstrated few strong brain behaviour relationships, with significant findings emerging only in the cingulum bundle for Emotional Prosody and the genu for Phonological Processing.

CONCLUSION

The lack of clear relationships in the TBI group is discussed in terms of the likely disruption to cortical networks secondary to significant brain injuries.

Sociosexual and communication deficits after traumatic injury to the developing murine brain

Despite the life-long implications of social and communication dysfunction after pediatric traumatic brain injury, there is a poor understanding of these deficits in terms of their developmental trajectory and underlying mechanisms. In a well-characterized murine model of pediatric brain injury, we recently demonstrated that pronounced deficits in social interactions emerge across maturation to adulthood after injury at postnatal day (p) 21, approximating a toddler-aged child. Extending these findings, we here hypothesized that these social deficits are dependent upon brain maturation at the time of injury, and coincide with abnormal sociosexual behaviors and communication. Age-dependent vulnerability of the developing brain to social deficits was addressed by comparing behavioral and neuroanatomical outcomes in mice injured at either a pediatric age (p21) or during adolescence (p35). Sociosexual behaviors including social investigation and mounting were evaluated in a resident-intruder paradigm at adulthood. These outcomes were complemented by assays of urine scent marking and ultrasonic vocalizations as indices of social communication. We provide evidence of sociosexual deficits after brain injury at p21, which manifest as reduced mounting behavior and scent marking towards an unfamiliar female at adulthood. In contrast, with the exception of the loss of social recognition in a three-chamber social approach task, mice that received TBI at adolescence were remarkably resilient to social deficits at adulthood. Increased emission of ultrasonic vocalizations (USVs) as well as preferential emission of high frequency USVs after injury was dependent upon both the stimulus and prior social experience. Contrary to the hypothesis that changes in white matter volume may underlie social dysfunction, injury at both p21 and p35 resulted in a similar degree of atrophy of the corpus callosum by adulthood. However, loss of hippocampal tissue was greater after p21 compared to p35 injury, suggesting that a longer period of lesion progression or differences in the kinetics of secondary pathogenesis after p21 injury may contribute to observed behavioral differences. Together, these findings indicate vulnerability of the developing brain to social dysfunction, and suggest that a younger age-at-insult results in poorer social and sociosexual outcomes.

Multi-modal MRI of mild traumatic brain injury

Multi-modal magnetic resonance imaging (MRI) that included high resolution structural imaging, diffusion tensor imaging (DTI), magnetization transfer ratio (MTR) imaging, and magnetic resonance spectroscopic imaging (MRSI) were performed in mild traumatic brain injury (mTBI) patients with negative computed tomographic scans and in an orthopedic-injured (OI) group without concomitant injury to the brain. The OI group served as a comparison group for mTBI. MRI scans were performed both in the acute phase of injury (~24 h) and at follow-up (~90 days). DTI data was analyzed using tract based spatial statistics (TBSS). Global and regional atrophies were calculated using tensor-based morphometry (TBM). MTR values were calculated using the standard method. MRSI was analyzed using LC Model. At the initial scan, the mean diffusivity (MD) was significantly higher in the mTBI cohort relative to the comparison group in several white matter (WM) regions that included internal capsule, external capsule, superior corona radiata, anterior corona radiata, posterior corona radiata, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major and forceps minor of the corpus callosum, superior longitudinal fasciculus, and corticospinal tract in the right hemisphere. TBSS analysis failed to detect significant differences in any DTI measures between the initial and follow-up scans either in the mTBI or OI group. No significant differences were found in MRSI, MTR or morphometry between the mTBI and OI cohorts either at the initial or follow-up scans with or without family wise error (FWE) correction. Our study suggests that a number of WM tracts are affected in mTBI in the acute phase of injury and that these changes disappear by 90 days. This study also suggests that none of the MRI-modalities used in this study, with the exception of DTI, is sensitive in detecting changes in the acute phase of mTBI.

Computer-automated focus lateralization of temporal lobe epilepsy using fMRI

PURPOSE

To compare the performance of computer-automated diagnosis using functional magnetic resonance imaging (fMRI) interictal graph theory (CADFIG) to that achieved in standard clinical practice with MRI, for lateralizing the affected hemisphere in temporal lobe epilepsy (TLE).

MATERIALS AND METHODS

Interictal resting state fMRI and high-resolution MRI were performed on 14 left and 10 right TLE patients. Functional topology measures were calculated from fMRI using graph theory, and used to lateralize the epileptogenic hemisphere using quadratic discriminant analysis. Leave-one-out cross-validation prediction accuracy of CADFIG was compared to performance based on expert manual analysis (MA) of MRI, using video EEG as the "gold standard" for focus lateralization.

RESULTS

CADFIG correctly lateralized 95.8% (23/24) of cases, compared to 66.7% (16/24) with expert MA of MRI. Combining MA with CADFIG allowed all cases (24/24) to be correctly lateralized. CADFIG correctly identified the affected hemisphere for all patients (8/8) where MRI failed to lateralize.

CONCLUSION

CADFIG based on fMRI lateralized the affected hemisphere in TLE with superior performance compared to expert MA of MRI. These results demonstrate that functional patterns in fMRI can be used with automated machine learning for diagnostic lateralization in TLE. Addition of fMRI-based tests to existing protocols for identifying the affected hemisphere in presurgical assessment can improve diagnostic accuracy and surgical outcome in TLE.

Psychiatric disorders in children and adolescents in the first six months after mild traumatic brain injury

The objective was to assess the nature, rate, predictive factors, and neurocognitive correlates of novel psychiatric disorders (NPD) after mild traumatic brain injury (MTBI). Children age 5-14 years with MTBI (N=87) from consecutive admissions to five trauma centers were enrolled and studied with semistructured psychiatric interviews soon after injury (baseline), and 70 of these children were assessed again 6 months post-injury. Injury severity; lesion characteristics; pre-injury variables, including psychiatric disorder, family psychiatric history, family functioning, socioeconomic status, psychosocial adversity, and adaptive functioning; and post-injury neurocognitive and adaptive functioning measures were assessed with standardized instruments. NPD occurred in 25 of 70 participants (36%) in the first 6 months after injury. NPD at 6 months was predicted by the presence of frontal white-matter lesions on MRI at 3 months post-injury, and was associated with concurrent decrements on neurocognitive indices of processing speed, expressive language, and intellectual functioning. NPD was not predicted by other indices of severity, pre-injury psychosocial variables, estimated pre-injury academic functioning, or adaptive and executive function decrements 6 months post-injury. These findings suggest that short-term psychiatric morbidity associated with MTBI in children and adolescents may be more common than previously thought and may have readily identifiable neuroimaging and neurocognitive correlates.

Cognitive sequelae of traumatic brain injury

Cognitive dysfunction is the leading cause of disability following traumatic brain injury (TBI). This article provides a review of the cognitive sequelae of TBI, with a focus on deficits of executive functioning and everyday thinking skills. The pathophysiology, assessment, and treatment of TBI-related cognitive problems are also discussed.

Patterns of early emotional and neuropsychological sequelae after mild traumatic brain injury

Although mild traumatic brain injury (mTBI) is now recognized as a major health issue, there have been relatively few studies of its acute effects. Previous studies of mTBI assessed at 1 week or less post-injury have produced inconsistent results, spanning reports of no ill effects to findings of robust dysfunction. These gross disparities reflect study differences such as the criteria for mTBI diagnosis and selection of comparison groups. In consideration of these issues, this study investigated outcome in the first 96 hours after injury in adolescents and adults ages 12-30 years with mTBI (n=73) compared with orthopedically injured (OI, n=65) and typically developing controls (TDC, n=40). The mTBI group reported significantly greater general psychological distress, post-concussion symptom severity, and post-traumatic stress severity than OI (all p<0.0001) and TDC (all p<0.0001); the OI and TDC groups responded similarly on these variables. There was a significant Group × Age interaction on the Total score (p<0.009), and the Cognitive (p=0.01) and Somatic (p<0.032) subscales of the Rivermead Post Concussion Symptoms Questionnaire where increasing symptom severity was associated with increasing age in the mTBI group. On neuropsychological assessment, the mTBI group performed significantly more poorly compared with OI for Verbal Selective Reminding Test (delayed recall, p=0.0003) and Symbol-Digit Modalities Test (SDMT written p=0.03; oral, p=0.001). The TDC group more robustly outperformed the mTBI group on these measures and also on the Brief Visuospatial Memory Test (delayed recall, p<0.04), Letter Fluency (p<0.02), and Category Switching (p<0.04). The TDC group outperformed the OI group on SDMT and Letter Fluency. These findings are consistent with previous reports of acute deficits in episodic memory and processing speed acutely after mTBI. Notably, however, these data also demonstrate the challenges of comparison group selection because differences were also found between the TDC and OI groups.

Functional connectivity of hippocampal networks in temporal lobe epilepsy

OBJECTIVE

Temporal lobe epilepsy (TLE) affects brain areas beyond the temporal lobes due to connections of the hippocampi and other temporal lobe structures. Using functional connectivity magnetic resonance imaging (MRI), we determined the changes of hippocampal networks in TLE to assess for a more complete distribution of abnormality.

METHODS

Regions of interest (ROIs) were defined in the right and left hippocampi in three groups of participants: left TLE (n = 13), right TLE (n = 11), and healthy controls (n = 16). Brain regions functionally connected to these ROIs were identified by correlating resting-state low-frequency functional MRI (fMRI) blood oxygenation level-dependent (BOLD) signal fluctuations. The grouped results were compared using independent sample t-test.

RESULTS

TLE was associated with increased hippocampal connectivity involving several key areas of the limbic network (temporal lobe, insula, thalamus), frontal lobes, angular gyrus, basal ganglia, brainstem, and cerebellum, along with reduced connectivity involving areas of the sensorimotor cortex (visual, somatosensory, auditory, primary motor) and the default mode network (precuneus). Left TLE had more marked connectivity changes than right TLE.

SIGNIFICANCE

The observed connectivity changes in TLE indicate dysfunctional networks that underlie widespread brain involvement in TLE. There are identifiable differences in the connectivity of the hippocampi between left and right TLE.

Evidence That the Blood Biomarker SNTF Predicts Brain Imaging Changes and Persistent Cognitive Dysfunction in Mild TBI Patients

Although mild traumatic brain injury (mTBI), or concussion, is not typically associated with abnormalities on computed tomography (CT), it nevertheless causes persistent cognitive dysfunction for many patients. Consequently, new prognostic methods for mTBI are needed to identify at risk cases, especially at an early and potentially treatable stage. Here, we quantified plasma levels of the neurodegeneration biomarker calpain-cleaved αII-spectrin N-terminal fragment (SNTF) from 38 participants with CT-negative mTBI, orthopedic injury (OI), and normal uninjured controls (UCs) (age range 12–30 years), and compared them with findings from diffusion tensor imaging (DTI) and long-term cognitive assessment. SNTF levels were at least twice the lower limit of detection in 7 of 17 mTBI cases and in 3 of 13 OI cases, but in none of the UCs. An elevation in plasma SNTF corresponded with significant differences in fractional anisotropy and the apparent diffusion coefficient in the corpus callosum and uncinate fasciculus measured by DTI. Furthermore, increased plasma SNTF on the day of injury correlated significantly with cognitive impairment that persisted for at least 3 months, both across all study participants and also among the mTBI cases by themselves. The elevation in plasma SNTF in the subset of OI cases, accompanied by corresponding white matter and cognitive abnormalities, raises the possibility of identifying undiagnosed cases of mTBI. These data suggest that the blood level of SNTF on the day of a CT-negative mTBI may identify a subset of patients at risk of white matter damage and persistent disability. SNTF could have prognostic and diagnostic utilities in the assessment and treatment of mTBI.

Electroencephalography and quantitative electroencephalography in mild traumatic brain injury

Mild traumatic brain injury (mTBI) causes brain injury resulting in electrophysiologic abnormalities visible in electroencephalography (EEG) recordings. Quantitative EEG (qEEG) makes use of quantitative techniques to analyze EEG characteristics such as frequency, amplitude, coherence, power, phase, and symmetry over time independently or in combination. QEEG has been evaluated for its use in making a diagnosis of mTBI and assessing prognosis, including the likelihood of progressing to the postconcussive syndrome (PCS) phase. We review the EEG and qEEG changes of mTBI described in the literature. An attempt is made to separate the findings seen during the acute, subacute, and chronic phases after mTBI. Brief mention is also made of the neurobiological correlates of qEEG using neuroimaging techniques or in histopathology. Although the literature indicates the promise of qEEG in making a diagnosis and indicating prognosis of mTBI, further study is needed to corroborate and refine these methods.

Preinjury resilience and mood as predictors of early outcome following mild traumatic brain injury

There is significant heterogeneity in outcomes following mild traumatic brain injury (mTBI). While several host factors (age, gender, and preinjury psychiatric history) have been investigated, the influence of preinjury psychological resilience and mood status in conjunction with mild TBI remains relatively unexplored. Euthymic mood and high resilience are potentially protective against anxiety and postconcussion symptoms, but their relative contributions are currently unknown. This prospective study obtained preinjury estimates of resilience and mood measures in addition to measures of anxiety (Acute Stress Disorder Scale and PTSD-Checklist-Civilian form) and postconcussion symptom severity (Rivermead Post Concussion Symptoms Questionnaire) <24 hours (Baseline), 1 week, and 1 month postinjury in patients with either mTBI (n=46) or a comparison group with orthopedic injuries not involving the head (OI, n=29). The groups did not differ on preinjury resilience or mood status at baseline, but differed significantly on measures of anxiety and postconcussion symptom severity at each subsequent study occasion. Multivariate linear regression analyses were conducted to determine if preinjury resilience and mood were significant contributors to anxiety and postconcussion symptoms during the first month postinjury after accounting for other known host factors (e.g., age at injury, gender, and education). Injury group and preinjury mood status were significant predictors for all three dependent variables at each study occasion (all p<0.007). Preinjury resilience showed a positive trend only for acute stress severity at baseline, but demonstrated significant prediction of all three dependent measures at one week and one month postinjury. These results suggest that preinjury depressed mood and resilience are significant contributors to the severity of postinjury anxiety and postconcussion symptoms, even after accounting for effects of other specific host factors.

Neural activation during response inhibition differentiates blast from mechanical causes of mild to moderate traumatic brain injury

Military personnel involved in Operations Enduring Freedom and Iraqi Freedom (OEF/OIF) commonly experience blast-induced mild to moderate traumatic brain injury (TBI). In this study, we used task-activated functional MRI (fMRI) to determine if blast-related TBI has a differential impact on brain activation in comparison with TBI caused primarily by mechanical forces in civilian settings. Four groups participated: (1) blast-related military TBI (milTBI; n=21); (2) military controls (milCON; n=22); (3) non-blast civilian TBI (civTBI; n=21); and (4) civilian controls (civCON; n=23) with orthopedic injuries. Mild to moderate TBI (MTBI) occurred 1 to 6 years before enrollment. Participants completed the Stop Signal Task (SST), a measure of inhibitory control, while undergoing fMRI. Brain activation was evaluated with 2 (mil, civ)×2 (TBI, CON) analyses of variance, corrected for multiple comparisons. During correct inhibitions, fMRI activation was lower in the TBI than CON subjects in regions commonly associated with inhibitory control and the default mode network. In contrast, inhibitory failures showed significant interaction effects in the bilateral inferior temporal, left superior temporal, caudate, and cerebellar regions. Specifically, the milTBI group demonstrated more activation than the milCON group when failing to inhibit; in contrast, the civTBI group exhibited less activation than the civCON group. Covariance analyses controlling for the effects of education and self-reported psychological symptoms did not alter the brain activation findings. These results indicate that the chronic effects of TBI are associated with abnormal brain activation during successful response inhibition. During failed inhibition, the pattern of activation distinguished military from civilian TBI, suggesting that blast-related TBI has a unique effect on brain function that can be distinguished from TBI resulting from mechanical forces associated with sports or motor vehicle accidents. The implications of these findings for diagnosis and treatment of TBI are discussed.

A history of low birth weight alters recovery following a future head injury: a case series

OBJECTIVE

Low birth weight (LBW; below 2500 grams) is a general risk factor for a variety of neurodevelopmental difficulties. However, these children may remain more vulnerable to neurologic and environmental insults occurring years later. This prospective case series reports on children who sustained a mild, moderate, or severe traumatic brain injury (TBI) in middle childhood but who had also been born with birth weights below 2500 grams.

PARTICIPANTS

PARTICIPANTS were 14 children with mild, moderate, or severe traumatic brain injury (TBI), 5 of whom had birth weights under 2500 grams (LBW) and 9 children with normal birth weight (NBW). All participants were drawn from a larger study on the long-term cognitive and behavioral impact of pediatric TBI and were matched on age, estimated socioeconomic status (SES), and severity of TBI (with NBW children actually having a slightly worse overall injury severity).

RESULTS

At baseline, both groups exhibited similar scores on WJ-R Letter Word Identification and Calculations, Tower of London number solved, and CVLT-C total correct. Baseline group differences were observed on the CELF-III Formulated Sentences (NBW > LBW) and on the VABS Adaptive Behavior Composite and Socialization subdomain (LBW > NBW). Over 2 years, relative to the NBW group, the LBW group evidenced declines on both WJ-R subtests, CVLT-C total correct, CELF-III Formulated Sentences, and VABS Adaptive Behavior Composite and Socialization.

CONCLUSIONS

Although preliminary in nature due to small sample size, findings suggest a history of LBW influences the recovery trajectory following childhood TBI. Academic and adaptive functioning and verbal memory appeared particularly affected.

Psychiatric disorders after pediatric traumatic brain injury: a prospective, longitudinal, controlled study

The objective was to examine the effects of traumatic brain injury (TBI), as compared with orthopedic injury (OI), relative to the risk for psychiatric disorder. There has only been one previous prospective study of this nature. Participants were age 7-17 years at the time of hospitalization for either TBI (complicated mild-to-severe) or OI. The study used a prospective, longitudinal, controlled design, with standardized psychiatric assessments conducted at baseline (reflecting pre-injury functioning) and 3 months post-injury. Assessments of pre-injury psychiatric, adaptive functioning, family adversity, and family psychiatric history status were conducted. Severity of injury was assessed by standard clinical scales. The outcome measure was the presence of a psychiatric disorder not present before the injury ("novel"), during the first 3 months after TBI. Enrolled participants (N=141) included children with TBI (N=75) and with OI (N=66). The analyses focused on 118 children (84%) (TBI: N=65; OI: N=53) who returned for follow-up assessment at 3 months. Novel psychiatric disorder (NPD) occurred significantly more frequently in the TBI (32/65; 49%) than the OI (7/53; 13%) group. This difference was not accounted for by pre-injury lifetime psychiatric status; pre-injury adaptive functioning; pre-injury family adversity, family psychiatric history, socioeconomic status, injury severity, or age at injury. Furthermore, none of these variables significantly discriminated between children with TBI who developed, versus those who did not develop, NPD. These findings suggest that children with complicated mild-to-severe TBI are at significantly higher risk than OI-controls for the development of NPD in the first 3 months after injury.

Updating memory after mild traumatic brain injury and orthopedic injuries

Few studies have examined the trajectory of recovery of executive function (EF) after mild TBI (mTBI). Therefore, consensus has not been reached on the incidence and extent of EF impairment after mTBI. The present study investigated trajectory of change in executive memory over 3 months after mTBI on 59 right-handed participants with mTBI, as defined by Centers for Disease Control criteria, ages 14-30 years, recruited within 96 hours post-injury and tested <1 week (baseline), 1 month, and 3 months after injury. Also included were 58 participants with orthopedic injury (OI) and 27 typically developing (TD) non-injured participants with similar age, socioeconomic status, sex, and ethnicity. MRI data were acquired at baseline and 3 months. Although criteria included a normal CT scan, lesions were detected by MRI in 19 mTBI patients. Participants completed the KeepTrack task, a verbal recall task placing demands on goal maintenance, semantic memory, and memory updating. Scores reflected items recalled and semantic categories maintained. The mTBI group was divided into two groups: high (score ≥12) or low (score <12) symptoms based on the Rivermead Post-Concussion Symptoms Questionnaire (RPQ). Mixed model analyses revealed the trajectory of change in mTBI patients (high and low RPQ), OI patients, and TD subjects were similar over time (although the TD group differed from other groups at baseline), suggesting no recovery from mTBI up to 90 days. For categories maintained, differences in trajectory of recovery were discovered, with the OI comparison group surprisingly performing similar to those in the mTBI group with high RPQ symptoms, and different from low RPQ and the TD groups, bringing up questions about utility of OIs as a comparison group for mTBI. Patients with frontal lesions (on MRI) were also found to perform worse than those without lesions, a pattern that became more pronounced with time.

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.

Neuropsychological outcome of mTBI: a principal component analysis approach

The multitude of variables associated with a battery of outcome measures presents a risk for spurious findings in clinical trials and observational studies of mild traumatic brain injury (mTBI). We have used principal components analysis (PCA) to facilitate data reduction by identifying components which represent subsets of neuropsychological measures that are selectively correlated with each other. By merging data from two concurrent mTBI studies using the same outcome measures, we obtained a cohort of 102 mTBI patients and 85 orthopedic injury (OI) comparison patients whom we recruited from 24 hours to 96 hours post-injury and evaluated at one week, 1 month, and 3 months post-injury. Cognitive domains included episodic memory, evaluated by both verbal and visual memory tasks, cognitive processing speed tests, and executive function. Post-concussion and stress-related symptoms were measured by rating scales. PCA identified four components, including cognitive processing speed, verbal memory, visual memory, and a symptom composite representing post-concussion and stress symptoms. mTBI patients older than the mean age of 18 years had slower cognitive processing than the OI patients, but there was no group difference in cognitive processing speed in younger patients. The symptom component score differed significantly as mTBI patients had more severe symptoms than the OI group at each occasion. Our results encourage replication with other cohorts using either the same outcome measures or at least similar domains. PCA is an approach to data reduction that could mitigate spurious findings and increase efficiency in mTBI research.

Response inhibition in children with and without ADHD after traumatic brain injury

Children with attention-deficit hyperactivity disorder (ADHD) and traumatic brain injury (TBI) show deficient response inhibition. ADHD itself is a common consequence of TBI, known as secondary ADHD (S-ADHD). Similarity in inhibitory control in children with TBI, S-ADHD, and ADHD would implicate impaired frontal-striatal systems; however, it is first necessary to delineate similarities and differences in inhibitory control in these conditions. We compared performance of children with ADHD and those with TBI without pre-injury ADHD on a stop signal, response inhibition task. Participants were 274 children aged 6-14 years. There were 92 children with ADHD, 103 children with TBI, and 79 typically developing children who served as controls. Among the TBI participants, injury severity ranged from mild to severe. Children with ADHD and TBI showed deficient inhibition. The deficit in children with ADHD was as great as or greater than that in children with TBI, regardless of degree of TBI severity or the presence of S-ADHD. The finding indicates that TBI results in deficient inhibition regardless of the development of S-ADHD.

Diffusion tensor imaging in moderate-to-severe pediatric traumatic brain injury: changes within an 18 month post-injury interval

Traumatic brain injury (TBI) is a leading cause of death and disability in children, yet little is known regarding the pattern of TBI-related microstructural change and its impact on subsequent development. Diffusion tensor imaging (DTI) was used to examine between-group differences at two time points (planned intervals of 3 months and 18 months post-injury) and within-group longitudinal change in a group of children and adolescents aged 7-17 years with moderate-to-severe TBI (n = 20) and a comparison group of children with orthopedic injury (OI) (n = 21). In the 3- and 18-month cross-sectional analyses, tract-based spatial statistics (TBSS) generally revealed decreased fractional anisotropy (FA) and increased apparent diffusion coefficient (ADC) in the TBI group in regions of frontal, temporal, parietal, and occipital white matter as well as several deep subcortical structures, though areas of FA decrease were more prominent at the 3-month assessment, and areas of ADC increase were more prominent at the 18 month assessment, particularly in the frontal regions. In terms of the within-group changes over time, the OI group demonstrated primarily diffuse increases in FA over time, consistent with previous findings of DTI-measured white matter developmental change. The TBI group demonstrated primarily regions of FA decrease and ADC increase over time, consistent with presumed continued degenerative change, though regions of ADC decrease were also appreciated. These results suggest that TBI-related microstructural changes are dynamic in children and continue until at least 18 months post-injury. Understanding the course of these changes in DTI metrics may be important in TBI for facilitating advances in management and intervention.

Psychiatric disorders in children and adolescents six-to-twelve months after mild traumatic brain injury

The objective of this study was to understand how novel psychiatric disorders (NPD) in children with mild traumatic brain injury (MTBI) are related to pre-injury variables, injury-related variables, and concurrent neurocognitive outcome. A group of 79 children, ages 5 to 14 years, who had experienced MTBI, were studied from consecutive hospital admissions with semistructured psychiatric interviews soon after injury (baseline); 60 children were reassessed 12 months post-injury. Standardized instruments were used to assess injury severity; lesion characteristics; pre-injury variables, including psychiatric disorder, family psychiatric history, family functioning, socioeconomic status, psychosocial adversity, adaptive functioning, and post-injury neurocognitive and adaptive functioning. NPD occurred in 17 of 60 participants (28%) in the 6-12-month interval after injury, with disorders that were significantly associated with socioeconomic status, psychosocial adversity, estimated pre-injury academic functioning, and concurrent deficits in adaptive functioning, academic performance, processing speed, memory, and expressive language. NPD was not significantly associated with pre-injury adaptive functioning, injury severity, family psychiatric history, pre-injury psychiatric disorder, lesion location, gender, or age at injury. These findings suggest that the short-term psychiatric morbidity associated with MTBI in children occurs more commonly than previously reported and is related to both pre-injury social factors and concurrent neurocognitive functioning.

Neuroimaging correlates of novel psychiatric disorders after pediatric traumatic brain injury

OBJECTIVE

To study magnetic resonance imaging (MRI) correlates of novel (new-onset) psychiatric disorders (NPD) after traumatic brain injury (TBI) and orthopedic injury (OI).

METHOD

Participants were 7 to 17 years of age at the time of hospitalization for either TBI or OI. The study used a prospective, longitudinal, controlled design with standardized psychiatric assessments conducted at baseline (reflecting pre-injury function) and 3 months post-injury. MRI assessments including diffusion tensor imaging (DTI)-derived fractional anisotropy (FA), volumetric measures of gray and white matter regions, volumetric measures of lesions, and cortical thickness were conducted. Injury severity was assessed by standard clinical scales. The outcome measure was the presence of an NPD identified during the first 3 months after injury.

RESULTS

There were 88 participants (TBI, 44; OI, 44). NPD occurred more frequently in the TBI (21/44; 48%) versus the OI (6/44; 14%) group (Fisher's exact test, p = .001). NPD in TBI participants was not related to injury severity. Multivariate analysis of covariance of the relationship between FA in hypothesized regions of interest (bilateral frontal and temporal lobes, bilateral centrum semiovale, bilateral uncinate fasciculi) and NPD and group (TBI versus OI) was significant, and both variables (NPD, p < .05; group, p < .001) were jointly significantly related to FA. NPD was not significantly related to volumetric measures of white or gray matter structures, volumetric measures of lesions, or cortical thickness measures.

CONCLUSIONS

Lowered white matter integrity may be more important in the pathophysiology of NPD than indices of gray matter or white matter atrophic changes, macroscopic lesions, and injury severity.

Early induction of hypothermia for evacuated intracranial hematomas: a post hoc analysis of two clinical trials

OBJECT

The authors hypothesized that cooling before evacuation of traumatic intracranial hematomas protects the brain from reperfusion injury and, if so, further hypothesized that hypothermia induction before or soon after craniotomy should be associated with improved outcomes.

METHODS

The National Acute Brain Injury Study: Hypothermia I (NABIS:H I) was a randomized multicenter clinical trial of 392 patients with severe brain injury treated using normothermia or hypothermia for 48 hours with patients reaching 33°C at 8.4 ± 3 hours after injury. The National Acute Brain Injury Study: Hypothermia II (NABIS:H II) was a randomized, multicenter clinical trial of 97 patients with severe brain injury treated with normothermia or hypothermia for 48 hours with patients reaching 35°C within 2.6 ± 1.2 hours and 33°C within 4.4 ± 1.5 hours of injury. Entry and exclusion criteria, management, and outcome measures in the 2 trials were similar.

RESULTS

In NABIS:H II among the patients with evacuated intracranial hematomas, outcome was poor (severe disability, vegetative state, or death) in 5 of 15 patients in the hypothermia group and in 9 of 13 patients in the normothermia group (relative risk 0.44, 95% CI 0.22-0.88; p = 0.02). All patients randomized to hypothermia reached 35°C within 1.5 hours after surgery start and 33°C within 5.55 hours. Applying these criteria to NABIS:H I, 31 of 54 hypothermia-treated patients reached a temperature of 35°C or lower within 1.5 hours after surgery start time, and the remaining 23 patients reached 35°C at later time points. Outcome was poor in 14 (45%) of 31 patients reaching 35°C within 1.5 hours of surgery, in 14 (61%) of 23 patients reaching 35°C more than 1.5 hours of surgery, and in 35 (60%) of 58 patients in the normothermia group (relative risk 0.74, 95%, CI 0.49-1.13; p = 0.16). A meta-analysis of 46 patients with hematomas in both trials who reached 35°C within 1.5 hours of surgery start showed a significantly reduced rate of poor outcomes (41%) compared with 94 patients treated with hypothermia who did not reach 35°C within that time and patients treated at normothermia (62%, p = 0.009).

CONCLUSIONS

Induction of hypothermia to 35°C before or soon after craniotomy with maintenance at 33°C for 48 hours thereafter may improve outcome of patients with hematomas and severe traumatic brain injury. Clinical trial registration no.: NCT00178711.

Recommendations for the use of common outcome measures in pediatric traumatic brain injury research

This article addresses the need for age-relevant outcome measures for traumatic brain injury (TBI) research and summarizes the recommendations by the inter-agency Pediatric TBI Outcomes Workgroup. The Pediatric Workgroup's recommendations address primary clinical research objectives including characterizing course of recovery from TBI, prediction of later outcome, measurement of treatment effects, and comparison of outcomes across studies. Consistent with other Common Data Elements (CDE) Workgroups, the Pediatric TBI Outcomes Workgroup adopted the standard three-tier system in its selection of measures. In the first tier, core measures included valid, robust, and widely applicable outcome measures with proven utility in pediatric TBI from each identified domain including academics, adaptive and daily living skills, family and environment, global outcome, health-related quality of life, infant and toddler measures, language and communication, neuropsychological impairment, physical functioning, psychiatric and psychological functioning, recovery of consciousness, social role participation and social competence, social cognition, and TBI-related symptoms. In the second tier, supplemental measures were recommended for consideration in TBI research focusing on specific topics or populations. In the third tier, emerging measures included important instruments currently under development, in the process of validation, or nearing the point of published findings that have significant potential to be superior to measures in the core and supplemental lists and may eventually replace them as evidence for their utility emerges.

Monetary incentive effects on event-based prospective memory three months after traumatic brain injury in children

Information regarding the remediation of event-based prospective memory (EB-PM) impairments following pediatric traumatic brain injury (TBI) is scarce. Addressing this, two levels of monetary incentives were used to improve EB-PM in children ages 7 to 16 years with orthopedic injuries (OI, n = 51), or moderate (n = 25) and severe (n = 39) TBI at approximately 3 months postinjury. The EB-PM task consisted of the child giving a specific verbal response to a verbal cue from the examiner while performing a battery of neuropsychological measures (ongoing task). Significant effects were found for age-at-test, motivation condition, period, and group. Within-group analyses indicated that OI and moderate TBI groups performed significantly better under the high- than under the low-incentive condition, but the severe TBI group demonstrated no significant improvement. These results indicate that EB-PM can be significantly improved at 3 months postinjury in children with moderate, but not severe, TBI.

Depression in children and adolescents in the first 6 months after traumatic brain injury

The objective was to assess the nature, rate, predictive factors, and neuroimaging correlates of novel (new-onset) depressive disorders, both definite and subclinical, after traumatic brain injury (TBI). Children with TBI from consecutive admissions were enrolled and studied with psychiatric interviews soon after injury (baseline), and again 6 months post-injury. Novel definite/subclinical depressive disorders at 6-month follow up occurred in 11% (n=15) of the children and subsets of children with non-anxious depression (n=9) and anxious depression (n=6) were identified. Novel definite/subclinical depressive disorder was significantly associated with older age at the time of injury, family history of anxiety disorder, left inferior frontal gyrus (IFG) lesions, and right frontal white matter lesions. Non-anxious depressions were associated with older age at injury, left IFG and left temporal pole lesions. Anxious depressions were associated with family history of anxiety disorder, Personality Change due to TBI, right frontal white matter lesions, and left parietal lesions. These findings, which are similar to those reported after adult TBI, identify both similarities and differences in non-anxious and anxious depression following childhood TBI with respect to lesion laterality, genetic factors (in the form of family psychiatric history of anxiety disorder), age at injury, and more generalized affective dysregulation.

Anxiety disorders in children and adolescents in the first six months after traumatic brain injury

The study's objective was to assess the nature, rate, predictive factors, and neuroimaging correlates of novel (new-onset) definite anxiety disorders and novel definite/subclinical anxiety disorders (in a broader group of children with at least subclinical anxiety disorders) after traumatic brain injury (TBI). Children with TBI from consecutive admissions to five trauma centers were enrolled and studied with psychiatric interviews soon after injury (baseline) and again 6 months post-injury. Novel definite anxiety disorder and novel definite/subclinical anxiety disorders were heterogeneous and occurred in 8.5% (N=12) and 17% (N=24) of participants, respectively, in the first 6 months after injury. Novel definite anxiety disorder was significantly associated with younger age at injury and tended to be associated with novel depressive disorder, as well as lesions of the superior frontal gyrus. Novel definite/subclinical anxiety disorder was significantly associated with concurrent psychiatric problems of personality change due to TBI and novel definite/subclinical depressive disorder, as well as with lesions of the superior frontal gyrus and a trend-association with frontal lobe white-matter lesions. These findings suggest that anxiety after childhood TBI may be part of a broader problem of affective dysregulation related to damaged dorsal frontal lobe and frontal white-matter systems, with younger children being at greatest risk for developing novel anxiety disorder after TBI.

Decision making after pediatric traumatic brain injury: trajectory of recovery and relationship to age and gender

The aim of the study was to examine longitudinal patterns of decision making based on risk and reward using a modified version of the Iowa Gambling Task (IGT) in children who had sustained traumatic brain injury (TBI) and children with orthopedic injury (OI). Participants were 135 children and adolescents with TBI (n=71) or OI (n=64) who were 7-17 years at the time of injury were enrolled and assessed prospectively at baseline and at follow-up intervals of 3, 12, 18, and 24 months after injury. Groups were similar in age, socioeconomic status, and gender. Participants chose from four decks of cards with the aim of maximizing earnings across 100 trials. Two of the decks offered relatively small rewards and relatively small losses, but were advantageous over the course of the experiment. The other two decks offered large rewards, but also introduced occasional large losses, and were considered disadvantageous over the course of the experiment. The variable of interest was the proportion of advantageous decks chosen across trials. Longitudinal analysis of the pattern of change across 2 years revealed a three-way interaction among injury group, age, and the quadratic term of interval-since-injury. In this interaction, the effect of age weakened in the TBI group across time, as compared to the OI group, which showed stronger quadratic patterns across the recovery intervals that differed by age. The OI group generally outperformed the TBI group. In addition, analyses revealed a three-way interaction among group, gender and the cubic term of post-injury interval, such that overall, males improved a great deal with time, but females showed small gains, regardless of injury group.

The relationship of resting cerebral blood flow and brain activation during a social cognition task in adolescents with chronic moderate to severe traumatic brain injury: a preliminary investigation

Alterations in cerebrovascular function are evident acutely in moderate to severe traumatic brain injury (TBI), although less is known about their chronic effects. Adolescent and adult patients with moderate to severe TBI have been reported to demonstrate diffuse activation throughout the brain during functional magnetic resonance imaging (fMRI). Because fMRI is a measure related to blood flow, it is possible that any deficits in blood flow may alter activation. An arterial spin labeling (ASL) perfusion sequence was performed on seven adolescents with chronic moderate to severe TBI and seven typically developing (TD) adolescents during the same session in which they had performed a social cognition task during fMRI. In the TD group, prefrontal CBF was positively related to prefrontal activation and negatively related to non-prefrontal, posterior, brain activation. This relationship was not seen in the TBI group, who demonstrated a greater positive relationship between prefrontal CBF and non-prefrontal activation than the TD group. An analysis of CBF data independent of fMRI showed reduced CBF in the right non-prefrontal region (p<.055) in the TBI group. To understand any role reduced CBF may play in diffuse extra-activation, we then related the right non-prefrontal CBF to activation. CBF in the right non-prefrontal region in the TD group was positively associated with prefrontal activation, suggesting an interactive role of non-prefrontal and prefrontal blood flow throughout the right hemisphere in healthy brains. However, the TBI group demonstrated a positive association with activation constrained to the right non-prefrontal region. These data suggest a relationship between impaired non-prefrontal CBF and the presence of non-prefrontal extra-activation, where the region with more limited blood flow is associated with activation limited to that region. In a secondary analysis, pathology associated with hyperintensities on T2-weighted FLAIR imaging over the whole brain was related to whole brain activation, revealing a negative relationship between lesion volume and frontal activation, and a positive relationship between lesion volume and posterior activation. These preliminary data, albeit collected with small sample sizes, suggest that reduced non-prefrontal CBF, and possibly pathological tissue associated with T2-hyperintensities, may provide contributions to the diffuse, primarily posterior extra-activation observed in adolescents following moderate to severe TBI.

Mental state attributions and diffusion tensor imaging after traumatic brain injury in children

We studied social cognition in 49 children 3 months after moderate to severe traumatic brain injury (TBI) and in 39 children with orthopedic injury (OI). Children underwent diffusion tensor imaging (DTI) and a mental attribution task showing two triangles. Mental state attributions increased when one triangle reacted to intentions of the other, but less so in the TBI than the OI group. DTI identified injury to white matter microstructure in the TBI group, but the relation of DTI to mental attributions did not differ between groups. Moderate to severe TBI produces white matter disconnections that may affect social cognitive networks.

Brain activation during a social attribution task in adolescents with moderate to severe traumatic brain injury

The ability to make accurate judgments about the mental states of others, sometimes referred to as theory of mind (ToM), is often impaired following traumatic brain injury (TBI), and this deficit may contribute to problems with interpersonal relationships. The present study used an animated social attribution task (SAT) with functional magnetic resonance imaging (fMRI) to examine structures mediating ToM in adolescents with moderate to severe TBI. The study design also included a comparison group of matched, typically developing (TD) adolescents. The TD group exhibited activation within a number of areas that are thought to be relevant to ToM, including the medial prefrontal and anterior cingulate cortex, fusiform gyrus, and posterior temporal and parietal areas. The TBI subjects had significant activation within many of these same areas, but their activation was generally more intense and excluded the medial prefrontal cortex. Exploratory regression analyses indicated a negative relation between ToM-related activation and measures of white matter integrity derived from diffusion tensor imaging, while there was also a positive relation between activation and lesion volume. These findings are consistent with alterations in the level and pattern of brain activation that may be due to the combined influence of diffuse axonal injury and focal lesions.

Brain imaging correlates of verbal working memory in children following traumatic brain injury

Neural correlates of working memory (WM) based on the Sternberg Item Recognition Task (SIRT) were assessed in 40 children with moderate-to-severe traumatic brain injury (TBI) compared to 41 demographically-comparable children with orthopedic injury (OI). Multiple magnetic resonance imaging (MRI) methods assessed structural and functional brain correlates of WM, including volumetric and cortical thickness measures on all children; functional MRI (fMRI) and diffusion tensor imaging (DTI) were performed on a subset of children. Confirming previous findings, children with TBI had decreased cortical thickness and volume as compared to the OI group. Although the findings did not confirm the predicted relation of decreased frontal lobe cortical thickness and volume to SIRT performance, left parietal volume was negatively related to reaction time (RT). In contrast, cortical thickness was positively related to SIRT accuracy and RT in the OI group, particularly in aspects of the frontal and parietal lobes, but these relationships were less robust in the TBI group. We attribute these findings to disrupted fronto-parietal functioning in attention and WM. fMRI results from a subsample demonstrated fronto-temporal activation in the OI group, and parietal activation in the TBI group, and DTI findings reflected multiple differences in white matter tracts that engage fronto-parietal networks. Diminished white matter integrity of the frontal lobes and cingulum bundle as measured by DTI was associated with longer RT on the SIRT. Across modalities, the cingulate emerged as a common structure related to performance after TBI. These results are discussed in terms of how different imaging modalities tap different types of pathologic correlates of brain injury and their relationship with WM.

Diffusion tensor imaging of the perforant pathway zone and its relation to memory function in patients with severe traumatic brain injury

Based on the importance of the perforant pathway (PP) for normal hippocampal function, the vulnerability of temporal structures, and significant memory impairment in patients with traumatic brain injury (TBI), we investigated in vivo changes in the PP zone, hippocampus, and temporal lobe white and gray matter using diffusion tensor imaging (DTI) and volumetric analysis, and any specific relations with memory performance (Verbal Selective Reminding Test, Rey-Osterrieth Complex Figure Test), in 14 patients with severe TBI. Compared to a demographically-similar control group, our patients had significantly decreased fractional anisotropy (FA) and higher apparent diffusion coefficient (ADC) for the PP zone bilaterally, and higher ADC bilaterally in the hippocampus. Volumetric analysis revealed significantly decreased volumes in both hippocampi and temporal gray matter bilaterally. Consistent long-term retrieval (CLTR) and delayed recall were significantly related to (1) right and left PP zone ADC, (2) left hippocampus ADC, and (3) left hippocampal volume. Nonverbal memory (immediate and delayed recall) was significantly associated with (1) right and left PP zone ADC, (2) left hippocampal volume, and (3) gray (immediate recall) and white (immediate recall, bilaterally; delayed recall, left) matter temporal volumes. Advanced neuroimaging analysis can detect in vivo changes in the PP zone and temporal structures in patients with severe TBI, with these changes being highly associated with memory impairment.