Using magnetic resonance imaging to predict new learning outcome at 5 years after childhood traumatic brain injury

Diffuse axonal injury on magnetic resonance imaging and its relation to neurological outcomes in pediatric traumatic brain injury

OBJECTIVE

Diffuse axonal injury (DAI), a frequent consequence of pediatric traumatic brain injury (TBI), presents challenges in predicting long-term recovery. This study investigates the relationship between the severity of DAI and neurological outcomes in children.

METHODS

We conducted a retrospective analysis of 51 pediatric TBI patients diagnosed with DAI using Adam's classification. Neurological function was assessed at 2, 3, and 6 weeks, and 12 months post-injury using the Pediatric Glasgow Outcome Scale-Extended (PGOSE).

RESULTS

PGOSE scores significantly improved over time across all DAI grades, suggesting substantial recovery potential even in initially severe cases. Despite indicating extensive injury, patients with DAI grades II and III demonstrated significant improvement, achieving a good recovery by 12 months. Although the initial Glasgow Coma Scale (GCS) score did not show a statistically significant association with long-term outcomes in our limited sample, these findings suggest that the severity of DAI alone may not fully predict eventual recovery.

CONCLUSIONS

Our study highlights the potential for significant neurological recovery in pediatric patients with DAI, emphasizing the importance of long-term follow-up and individualized rehabilitation programs. Further research with larger cohorts and extended follow-up periods is crucial to refine our understanding of the complex relationships between DAI severity, injury mechanisms, and long-term neurological outcomes in children.

Pediatric concussion working memory outcomes: a scoping review

Objective: Characterize the working memory (WM) profile of children and youth who have experienced concussion by systematically synthesizing existing literature on the neuropsychological outcomes of these injuries.Methods: Implemented a peer-reviewed search strategy combining key concepts of concussion/mild traumatic brain injury (mTBI), WM, and pediatrics across MedLine, Embase, PsycINFO, and CINAHL. Included studies written in English with extractable results on a WM outcome measure in individuals aged 21 and under who experienced concussion. Applied narrative synthesis to identify trends in the literature. Assessed risk of bias and quality using the NHLBI's Quality Assessment of Observational Cohort and Cross-Sectional Studies.Results: 40 articles met inclusion criteria. 34/40 studies compared WM performance in children or youth with concussion to healthy controls, pre-injury performance, or normative values, of which 15 reported significantly lower WM performance in the concussion sample. Visual/spatial WM was more consistently impacted than verbal WM. Cognitive demanding dual-task conditions were also reliably impacted.Conclusion: Literature indicated that WM is vulnerable to negative outcomes following pediatric concussion, yet the nature of outcomes is variable. Clinicians and researchers should implement comprehensive and theoretically motivated WM assessments to better understand the WM components impacted by injury.

Traumatic Injury to the Developing Brain: Emerging Relationship to Early Life Stress

Despite the high incidence of brain injuries in children, we have yet to fully understand the unique vulnerability of a young brain to an injury and key determinants of long-term recovery. Here we consider how early life stress may influence recovery after an early age brain injury. Studies of early life stress alone reveal persistent structural and functional impairments at adulthood. We consider the interacting pathologies imposed by early life stress and subsequent brain injuries during early brain development as well as at adulthood. This review outlines how early life stress primes the immune cells of the brain and periphery to elicit a heightened response to injury. While the focus of this review is on early age traumatic brain injuries, there is also a consideration of preclinical models of neonatal hypoxia and stroke, as each further speaks to the vulnerability of the brain and reinforces those characteristics that are common across each of these injuries. Lastly, we identify a common mechanistic trend; namely, early life stress worsens outcomes independent of its temporal proximity to a brain injury.

Brain Magnetic Resonance Imaging Volumetric Measures of Functional Outcome after Severe Traumatic Brain Injury in Adolescents

Adolescent traumatic brain injury (TBI) is a major public health concern, resulting in >35,000 hospitalizations in the United States each year. Although neuroimaging is a primary diagnostic tool in the clinical assessment of TBI, our understanding of how specific neuroimaging findings relate to outcome remains limited. Our study aims to identify imaging biomarkers of long-term neurocognitive outcome after severe adolescent TBI. Twenty-four adolescents with severe TBI (Glasgow Coma Scale ≤8) enrolled in the ADAPT (Approaches and Decisions after Pediatric TBI) study were recruited for magnetic resonance imaging (MRI) scanning 1-2 years post-injury at 13 participating sites. Subjects underwent outcome assessments ∼1-year post-injury, including the Wechsler Abbreviated Scale of Intelligence (IQ) and the Pediatric Glasgow Outcome Scale-Extended (GOSE-Peds). A typically developing control cohort of 38 age-matched adolescents also underwent scanning and neurocognitive assessment. Brain-image segmentation was performed on T1-weighted images using Freesurfer. Brain and ventricular cerebrospinal fluid volumes were used to compute a ventricle-to-brain ratio (VBR) for each subject, and the corpus callosum cross-sectional area was determined in the midline for each subject. The TBI group demonstrated higher VBR and lower corpus callosum area compared to the control cohort. After adjusting for age and sex, VBR was significantly related with GOSE-Peds score in the TBI group (n = 24, p = 0.01, cumulative odds ratio = 2.18). After adjusting for age, sex, intracranial volume, and brain volume, corpus callosum cross-sectional area correlated significantly with IQ score in the TBI group (partial cor = 0.68, n = 18, p = 0.007) and with PSI (partial cor = 0.33, p = 0.02). No association was found between VBR and IQ or between corpus callosum and GOSE-Peds. After severe adolescent TBI, quantitative MRI measures of VBR and corpus callosum cross-sectional area are associated with global functional outcome and neurocognitive outcomes, respectively.

Longitudinal Neuroimaging in Pediatric Traumatic Brain Injury: Current State and Consideration of Factors That Influence Recovery

Traumatic brain injury (TBI) is a leading cause of death and disability for children and adolescents in the U.S. and other developed and developing countries. Injury to the immature brain varies greatly from that of the mature, adult brain due to numerous developmental, pre-injury, and injury-related factors that work together to influence the trajectory of recovery during the course of typical brain development. Substantial damage to brain structure often underlies subsequent functional limitations that persist for years following pediatric TBI. Advances in neuroimaging have established an important role in the acute management of pediatric TBI, and magnetic resonance imaging (MRI) techniques have a particular relevance for the sequential assessment of long-term consequences from injuries sustained to the developing brain. The present paper will discuss the various factors that influence recovery and review the findings from the present neuroimaging literature to assess altered development and long-term outcome following pediatric TBI. Four MR-based neuroimaging modalities have been used to examine recovery from pediatric TBI longitudinally: (1) T1-weighted structural MRI is sensitive to morphological changes in gray matter volume and cortical thickness, (2) diffusion-weighted MRI is sensitive to changes in the microstructural integrity of white matter, (3) MR spectroscopy provides a sensitive assessment of metabolic and neurochemical alterations in the brain, and (4) functional MRI provides insight into the functional changes that occur as a result of structural damage and typical developmental processes. As reviewed in this paper, 13 cohorts have contributed to only 20 studies published to date using neuroimaging to examine longitudinal changes after TBI in pediatric patients. The results of these studies demonstrate considerable heterogeneity in post-injury outcome; however, the existing literature consistently shows that alterations in brain structure, function, and metabolism can persist for an extended period of time post-injury. With larger sample sizes and multi-site cooperation, future studies will be able to further examine potential moderators of outcome, such as the developmental, pre-injury, and injury-related factors discussed in the present review.

Differential effects of minocycline on microglial activation and neurodegeneration following closed head injury in the neonate rat

The role of microglia in the pathophysiology of injury to the developing brain has been extensively studied. In children under the age of 4 who have sustained a traumatic brain injury (TBI), markers of microglial/macrophage activation were increased in the cerebrospinal fluid and were associated with worse neurologic outcome. Minocycline is an antibiotic that decreases microglial/macrophage activation following hypoxic-ischemia in neonatal rodents and TBI in adult rodents thereby reducing neurodegeneration and behavioral deficits. In study 1, 11-day-old rats received an impact to the intact skull and were treated for 3days with minocycline. Immediately following termination of minocycline administration, microglial reactivity was reduced in the cortex and hippocampus (p<0.001) and was accompanied by an increase in the number of fluoro-Jade B profiles (p<0.001) suggestive of a reduced clearance of degenerating cells; however, this effect was not sustained at 7days post-injury. Although microglial reactivity was reduced in the white matter tracts (p<0.001), minocycline treatment did not reduce axonal injury or degeneration. In the thalamus, minocycline treatment did not affect microglial reactivity, axonal injury and degeneration, and neurodegeneration. Injury-induced spatial learning and memory deficits were also not affected by minocycline. In study 2, to test whether extended dosing of minocycline may be necessary to reduce the ongoing pathologic alterations, a separate group of animals received minocycline for 9days. Immediately following termination of treatment, microglial reactivity and neurodegeneration in all regions examined were exacerbated in minocycline-treated brain-injured animals compared to brain-injured animals that received vehicle (p<0.001), an effect that was only sustained in the cortex and hippocampus up to 15days post-injury (p<0.001). Whereas injury-induced spatial learning deficits remained unaffected by minocycline treatment, memory deficits appeared to be significantly worse (p<0.05). Sex had minimal effects on either injury-induced alterations or the efficacy of minocycline treatment. Collectively, these data demonstrate the differential effects of minocycline in the immature brain following impact trauma and suggest that minocycline may not be an effective therapeutic strategy for TBI in the immature brain.

Focal MRI and Learning Disability with Reduced Automaticity

Investigators from the Boston Children’s Hospital, Harvard Medical School, MA, performed a retrospective analysis of 1,587 children referred for a learning disability, and 127 had a focal deficit demonstrated on either a neurologic or neuropsychological evaluation.

[Formula: see text]Working memory outcomes following traumatic brain injury in children: A systematic review with meta-analysis

The aim of this review is to systematically examine the literature concerning multicomponent working memory (WM)-comprising a central executive (CE), two storage components (phonological loop, PL and visuo-spatial sketchpad, VSSP), and episodic buffer (EB)-in pediatric traumatic brain injury (TBI). Electronic searches were conducted of MEDLINE, PsychINFO and EMBASE up to October 2014 with the inclusion criteria of children and adolescents with TBI, and quantitative methods to assess at least one component of WM. Meta-analytic procedures calculated pooled effect sizes for WM outcomes. Of the studies examined, 27 met the inclusion criteria. Children with TBI exhibited deficits in the CE and PL, but not in the VSSP, and no study could be found which examined the EB. Qualitative analysis found that greater TBI severity was associated with poorer CE functioning in five out of nine studies. Differences in patterns of brain activation were evident in four out of five fMRI studies that examined WM in TBI children and controls. Deficits in CE were associated with poorer mathematical skills in the only study that examined relations between WM and academic deficits. Notwithstanding the heterogeneity of the studies reviewed, TBI places children at risk of WM deficits. Moreover, this meta-analysis suggests that various components of WM have differential vulnerability to pediatric TBI, with significant deficits found in the CE and PL, but not in the VSSP (although the VSSP has rarely been examined to date). Future studies should be theoretically driven, employ tasks assessing all components of the WM model and examine the functional ramifications (including academic outcomes) of WM deficits in this population.

Longitudinal changes in cortical thickness in children after traumatic brain injury and their relation to behavioral regulation and emotional control

The purpose of this study was to assess patterns of cortical development over time in children who had sustained traumatic brain injury (TBI) as compared to children with orthopedic injury (OI), and to examine how these patterns related to emotional control and behavioral dysregulation, two common post-TBI symptoms. Cortical thickness was measured at approximately 3 and 18 months post-injury in 20 children aged 8.2-17.5 years who had sustained moderate-to-severe closed head injury and 21 children aged 7.4-16.7 years who had sustained OI. At approximately 3 months post-injury, the TBI group evidenced decreased cortical thickness bilaterally in aspects of the superior frontal, dorsolateral frontal, orbital frontal, and anterior cingulate regions compared to the control cohort, areas of anticipated vulnerability to TBI-induced change. At 18 months post-injury, some of the regions previously evident at 3 months post-injury remained significantly decreased in the TBI group, including bilateral frontal, fusiform, and lingual regions. Additional regions of significant cortical thinning emerged at this time interval (bilateral frontal regions and fusiform gyrus and left parietal regions). However, differences in other regions appeared attenuated (no longer areas of significant cortical thinning) by 18 months post-injury including large bilateral regions of the medial aspects of the frontal lobes and anterior cingulate. Cortical thinning within the OI group was evident over time in dorsolateral frontal and temporal regions bilaterally and aspects of the left medial frontal and precuneus, and right inferior parietal regions. Longitudinal analyses within the TBI group revealed decreases in cortical thickness over time in numerous aspects throughout the right and left cortical surface, but with notable "sparing" of the right and left frontal and temporal poles, the medial aspects of both the frontal lobes, the left fusiform gyrus, and the cingulate bilaterally. An analysis of longitudinal changes in cortical thickness over time (18 months-3 months) in the TBI versus OI group demonstrated regions of relative cortical thinning in the TBI group in bilateral superior parietal and right paracentral regions, but relative cortical thickness increases in aspects of the medial orbital frontal lobes and bilateral cingulate and in the right lateral orbital frontal lobe. Finally, findings from analyses correlating the longitudinal cortical thickness changes in TBI with symptom report on the Emotional Control subscale of the Behavior Rating Inventory of Executive Function (BRIEF) demonstrated a region of significant correlation in the right medial frontal and right anterior cingulate gyrus. A region of significant correlation between the longitudinal cortical thickness changes in the TBI group and symptom report on the Behavioral Regulation Index was also seen in the medial aspect of the left frontal lobe. Longitudinal analyses of cortical thickness highlight an important deviation from the expected pattern of developmental change in children and adolescents with TBI, particularly in the medial frontal lobes, where typical patterns of thinning fail to occur over time. Regions which fail to undergo expected cortical thinning in the medial aspects of the frontal lobes correlate with difficulties in emotional control and behavioral regulation, common problems for youth with TBI. Examination of post-TBI brain development in children may be critical to identification of children that may be at risk for persistent problems with executive functioning deficits and the development of interventions to address these issues.

Detecting traumatic brain lesions in children: CT versus MRI versus susceptibility weighted imaging (SWI)

Cranial CT scans are at the center of decision making in brain injuries in children because of their speed and ability to detect surgically relevant lesions. However, alternative techniques, such as conventional MRI may have advantages in terms of radiation exposure and sensitivity to detect brain injury. Susceptibility-weighted imaging (SWI), a relatively novel MRI sequence, shows promise in terms of its sensitivity in detecting hemorrhagic lesions; however, its clinical potential remains uncertain. In this observational study of children (5-16 years of age) with traumatic brain injury (TBI) at a tertiary pediatric emergency department (ED) we compared the ability of detecting traumatic brain lesions on acute CT and MRI/SWI ∼ 5 weeks post-injury based on detecting the presence or absence, extent, and type of traumatic brain lesions. We analyzed the results of 76 patients (53 male) after TBI (mean age 10.24 ± 2.50 years, range 5.75-14.67 years). Glasgow Coma Score was 13-15 in 54 patients (71%), 9-12 in 13 patients (17%) and <8 in 9 patients (12%). CTs were completed in the ED; MRI and SWI were completed at a mean of 36.11 ± 15.75 days post-injury. Detection of any lesions occurred on CT scan in 68%, on MRI in 54%, and on SWI in 86% of cases, and SWI detected additional lesions 30% of the time compared to CT and MRI. SWI may be more sensitive in detecting traumatic lesions than CT or MRI. This may be important for the ongoing management of TBIs and their prognosis.

Diffusion tensor imaging of incentive effects in prospective memory after pediatric traumatic brain injury

Few studies exist investigating the brain-behavior relations of event-based prospective memory (EB-PM) impairments following traumatic brain injury (TBI). To address this, children with moderate-to-severe TBI performed an EB-PM test with two motivational enhancement conditions and underwent concurrent diffusion tensor imaging (DTI) at 3 months post-injury. Children with orthopedic injuries (OI; n=37) or moderate-to-severe TBI (n=40) were contrasted. Significant group differences were found for fractional anisotropy (FA) and apparent diffusion coefficient for orbitofrontal white matter (WM), cingulum bundles, and uncinate fasciculi. The FA of these WM structures in children with TBI significantly correlated with EB-PM performance in the high, but not the low motivation condition. Regression analyses within the TBI group indicated that the FA of the left cingulum bundle (p=0.003), left orbitofrontal WM (p<0.02), and left (p<0.02) and right (p<0.008) uncinate fasciculi significantly predicted EB-PM performance in the high motivation condition. We infer that the cingulum bundles, orbitofrontal WM, and uncinate fasciculi are important WM structures mediating motivation-based EB-PM responses following moderate-to-severe TBI in children.

Practitioner review: beyond shaken baby syndrome: what influences the outcomes for infants following traumatic brain injury?

BACKGROUND

Traumatic brain injury (TBI) in infancy is relatively common, and is likely to lead to poorer outcomes than injuries sustained later in childhood. While the headlines have been grabbed by infant TBI caused by abuse, often known as shaken baby syndrome, the evidence base for how to support children following TBI in infancy is thin. These children are likely to benefit from ongoing assessment and intervention, because brain injuries sustained in the first year of life can influence development in different ways over many years.

METHODS

A literature search was conducted and drawn together into a review aimed at informing practitioners working with children who had a brain injury in infancy. As there are so few evidence-based studies specifically looking at children who have sustained a TBI in infancy, ideas are drawn from a range of studies, including different age ranges and difficulties other than traumatic brain injury.

RESULTS

This paper outlines the issues around measuring outcomes for children following TBI in the first year of life. An explanation of outcomes which are more likely for children following TBI in infancy is provided, in the areas of mortality; convulsions; endocrine problems; sensory and motor skills; cognitive processing; language; academic attainments; executive functions; and psychosocial difficulties. The key factors influencing these outcomes are then set out, including severity of injury; pre-morbid situation; genetics; family factors and interventions.

CONCLUSIONS

Practitioners need to take a long-term, developmental view when assessing, understanding and supporting children who have sustained a TBI in their first year of life. The literature suggests some interventions which may be useful in prevention, acute care and longer-term rehabilitation, and further research is needed to assess their effectiveness.

Patterns of cortical thinning in relation to event-based prospective memory performance three months after moderate to severe traumatic brain injury in children

While event-based prospective memory (EB-PM) tasks are a familiar part of daily life for children, currently no data exists concerning the relation between EB-PM performance and brain volumetrics after traumatic brain injury (TBI). This study investigated EB-PM in children (7 to 17 years) with moderate to severe TBI or orthopedic injuries. Participants performed an EB-PM task and concurrently underwent neuroimaging at three months postinjury. Surface reconstruction and cortical thickness analysis were performed using FreeSurfer software. Cortical thickness was significantly correlated with EB-PM (adjusting for age). Significant thinning in the left (dorsolateral and inferior prefrontal cortex, anterior and posterior cingulate, temporal lobe, fusiform, and parahippocampal gyri), and right hemispheres (dorsolateral, inferior, and medial prefrontal cortex, cingulate, and temporal lobe) correlated positively and significantly with EB-PM performance; findings are comparable to those of functional neuroimaging and lesion studies of EB-PM.

Long-term cognitive outcome after neurosurgically treated childhood traumatic brain injury

OBJECTIVE

To explore the cognitive long-term outcome of two cohorts of patients neurosurgically treated for childhood traumatic brain injury (CTBI), either in 1987-1991 according to an older concept or 1997-2001 with a stronger emphasis on volume targeted interventions.

RESEARCH DESIGN AND METHODS

Participants in the two cohorts were subject to an extensive neuropsychological assessment, 13.2 and 6.1 years post-injury, respectively. In a between-group design, assessment results of the two cohorts, n = 18 and n = 23, were compared to each other and to controls. Data were analysed with multivariate analyses of variance.

RESULTS

Long-term cognitive deficits for both groups of similar magnitude and character were observed in both groups. Abilities were especially low regarding executive and memory function and verbal IQ. The cognitive results are discussed in terms of vulnerability of verbal functions and decreased executive control over memory-functions.

CONCLUSIONS

There is a definite need for long-term follow-up of cognitive deficits after neurosurgically treated CTBI, also with the newer neurosurgical concept. Verbal learning and the executive control over memory functions should be addressed with interventions aimed at restoration, coping and compensation.

Clinical management and functional neuromonitoring in traumatic brain injury in children

PURPOSE OF REVIEW

Traumatic brain injury is the main cause of childhood disability and death. In this review, we highlight recent original findings and emerging themes from published literature on children with serious traumatic brain injury.

RECENT FINDINGS

We focus this review on lessons learned from our recent randomized clinical trial of hypothermia therapy in severe traumatic brain injury in children and on bedside neuromonitoring. We propose that integrating the measurement of biomarkers into clinical care as surrogate endpoints and as potential prognostic markers would allow us to evaluate earlier the effect of injury and clinical care in children after traumatic brain injury. Several methods are now more readily available to monitor cerebral physiology in children. These methods include indices evaluating the integrity of cerebral autoregulation, such as the pressure reactivity index derived from values obtained from intracranial pressure measurements, flow velocity measurements from transcranial Doppler ultrasonography or from cerebral oximetry. Other methods allow the evaluation of coma with the nonlinear analysis of electroencephalography or the evaluation of cerebral metabolism and cell death pathways with biomarkers from serum, cerebral spinal fluid, and cerebral microdialysis.

SUMMARY

We suggest expanding clinical functional neuromonitoring to help clinicians understand the burden of exposure to physiological variables and response to therapies during intensive care in order to enhance the management of critically ill children with traumatic brain injury.

Working memory performance following paediatric traumatic brain injury

PRIMARY OBJECTIVE

The present study investigated working memory ability in children who sustained moderate-to-severe traumatic brain injuries in relation to pre-injury, injury-related and developmental factors. It was hypothesized that there would be a correlation between performance- and rater-based working memory measures; factors predictive of working memory impairment would include earlier age at injury, more severe injury, longer time since injury and poorer overall cognitive functioning; and working memory performance would be significantly impaired when compared to normative populations.

METHODS AND PROCEDURES

Working memory was assessed in 62 children using a traditional performance measure (digit span backward) and parent report (Behaviour Rating Inventory of Executive Function (BRIEF)).

MAIN OUTCOMES AND RESULTS

Contrary to prediction, there was no statistical association between performance- and rater-based measures of working memory. Regression analyses revealed injury severity, time-since-injury, overall cognitive ability and attention span were predictive of working memory performance. As a group, working memory was impaired relative to normative samples on both measures.

CONCLUSIONS

Performance- and rater-based working memory measures, while not significantly correlated, are both sensitive to acquired cognitive dysfunction following paediatric traumatic brain injury. Demographic and clinical factors may be used to predict cognitive outcomes, educate caregivers and design clinical interventions.