Structural Connectivity Related to Persistent Symptoms After Mild TBI in Adolescents and Response to Aerobic Training: Preliminary Investigation

Cortical Morphometric Similarity Remodeling in Traumatic Brain Injury Links Cognitive Impairments with Transcriptional Changes and Type-Specific Cells

The heterogeneous injuries and resulting cognitive deficits pose significant challenges in the clinical management of mild traumatic brain injury (mTBI). However, the pathophysiological mechanisms related to heterogeneities of mTBI are still unclear. This study aims to explore the mechanisms underlying brain remodeling by examining the morphometric similarity (MS) alterations and corresponding transcriptomic signatures across adult and pediatric mTBI (adult mTBI: 112 acute patients, 47 follow-up chronic patients, 66 healthy controls [HCs]; pediatric mTBI: 30 acute patients, 31 HCs). A healthy adult cohort (N = 840) is included to derive the modularized brain MS networks representing interregional cortical connectivity. Subsequently, cortical MS remodeling patterns are identified involving mostly MS increases in the frontal modules with typical high MS and decreases in the occipital module with typical low MS, with more pronounced changes observed in the developing brain with mTBI. The abnormal MS changes are correlated with variable cognitive impairments. Moreover, cortical MS remodeling is also associated with the genes enriched in CA1 pyramidal cells and neuron-specific biological processes. The transcription-related cortical remodeling in mTBI might reveal the disruption of brain cellular architecture. Therapeutic modalities to intervene in specific cortex and tackle CA1 over-activation might better encircle the neurobiology of TBI.

Concussion and the Autonomic, Immune, and Endocrine Systems: An Introduction to the Field and a Treatment Framework for Persisting Symptoms

A significant proportion of patients who sustain a concussion/mild traumatic brain injury endorse persisting, lingering symptoms. The symptoms associated with concussion are nonspecific, and many other medical conditions present with similar symptoms. Medical conditions that overlap symptomatically with concussion include anxiety, depression, insomnia, chronic pain, chronic fatigue, fibromyalgia, and cervical strain injuries. One of the factors that may account for these similarities is that these conditions all present with disturbances in the optimal functioning of the autonomic nervous system and its intricate interactions with the endocrine system and immune system-the three primary regulatory systems in the body. When clinicians are working with patients presenting with persisting symptoms after concussion, evidence-based treatment options drawn from the literature are limited. We present a framework for the assessment and treatment of persisting symptoms following concussion based on the available evidence (treatment trials), neuroanatomical principles (research into the physiology of concussion), and clinical judgment. We review the research supporting the premise that behavioral interventions designed to stabilize and optimize regulatory systems in the body following injury have the potential to reduce symptoms and improve functioning in patients. Foundational concussion rehabilitation strategies in the areas of sleep stabilization, fatigue management, physical exercise, nutrition, relaxation protocols, and behavioral activation are outlined along with practical strategies for implementing intervention modules with patients.

Evidence-Based Medical Management and Physiotherapy Rehabilitation in Pediatric Traumatic Brain Injury: A Narrative Review

Children between the ages of one and 18 are at a heightened risk of death and impairment due to traumatic brain injury (TBI). TBI can be deadly and is usually categorized as mild, moderate, or severe according to the Glasgow Coma Scale (GCS). For individuals with a TBI and an abnormal GCS, the preferred modality is non-contrast CT of the head. This review focuses on the medical treatment and rehabilitation of children with TBI and their outcomes. This was searched in databases such as PubMed, Google Scholar, and EMBASE. The literature search criteria included "traumatic brain injury AND physiotherapy rehabilitation OR medical treatment," with additional filters applied, including full text, both male and female, ages below 18 years, and publications from 2012 to 2024. This study conducted research on the treatment and rehabilitation of children with TBI. Ten randomized clinical trials, non-randomized trials, and longitudinal cohort study randomized trials met the inclusion criteria, which include hyperbaric oxygen therapy, melatonin, nabiximols, psycho-educational intervention, online therapy, the virtual reality rehabilitation program, and conventional occupational therapy. The results show significant improvement in forearm supination, performance in daily living, quality of life, reduced anger, improved school functioning, improvement in TBI conditions, reduced hospital stay, activity facilitating recovery, and reduced prolonged symptoms. This review has addressed the effectiveness of various medical management and rehabilitation strategies, which are important in TBI and aim to mitigate post-traumatic/concussion impact and improve quality of life. Articles regarding children's TBI rehabilitation are comparatively few. One possible solution to this issue would be to encourage further rehabilitation intervention trials.

Graph Analysis of the Visual Cortical Network during Naturalistic Movie Viewing Reveals Increased Integration and Decreased Segregation Following Mild TBI

Traditional neuroimaging methods have identified alterations in brain activity patterns following mild traumatic brain injury (mTBI), particularly during rest, complex tasks, and normal vision. However, studies using graph theory to examine brain network changes in mTBI have produced varied results, influenced by the specific networks and task demands analyzed. In our study, we employed functional MRI to observe 17 mTBI patients and 54 healthy individuals as they viewed a simple, non-narrative underwater film, simulating everyday visual tasks. This approach revealed significant mTBI-related changes in network connectivity, efficiency, and organization. Specifically, the mTBI group exhibited higher overall connectivity and local network specialization, suggesting enhanced information integration without overwhelming the brain's processing capabilities. Conversely, these patients showed reduced network segregation, indicating a less compartmentalized brain function compared to healthy controls. These patterns were consistent across various visual cortex subnetworks, except in primary visual areas. Our findings highlight the potential of using naturalistic stimuli in graph-based neuroimaging to understand brain network alterations in mTBI and possibly other conditions affecting brain integration.

Comparison of effectiveness between different interventions in postconcussive symptoms in adolescents and young people: a literature review

INTRODUCTION

Currently, concussion considers a problem of great magnitude, adolescents and young people being the population at risk, since it is in the process of maturation. Our goal has been to compare the effectiveness of different interventions (exercise therapy, vestibular rehabilitation and rest) in adolescents and young people with concussion.

DEVELOPMENT

A bibliographic search was carried out in the main databases. Once the inclusion/exclusion criteria and the PEDro methodological scale were applied, 6 articles were reviewed. The results support the use of exercise and vestibular rehabilitation in the initial stages to reduce post-concussion symptoms. According to most authors, therapeutic physical exercise and vestibular rehabilitation report greater benefits, although a protocol that unifies assessment scales, study variables and analysis parameters would be needed to be able to make the inference in the target population. CONCLUSIóN: From the moment of hospital discharge, the combined application of exercise and vestibular rehabilitation could be the best option to reduce post-concussion symptoms.

Prediction of cognitive outcome after mild traumatic brain injury from acute measures of communication within brain networks

A considerable but ill-defined proportion of patients with mild traumatic brain injury (mTBI) experience persistent cognitive sequelae; the ability to identify such individuals early can help their neurorehabilitation. Here we tested the hypothesis that acute measures of efficient communication within brain networks are associated with patients' risk for unfavorable cognitive outcome six months after mTBI. Diffusion and T1-weighted magnetic resonance imaging, alongside cognitive measures, were obtained to map connectomes both one week and six months post injury in 113 adult patients with mTBI (71 males). For task-related brain networks, communication measures (characteristic path length, global efficiency, navigation efficiency) were moderately correlated with changes in cognition. Taking into account the covariance of age and sex, more unfavorable communication within networks were associated with worse outcomes within cognitive domains frequently impacted by mTBI (episodic and working memory, verbal fluency, inductive reasoning, and processing speed). Individuals with more unfavorable outcomes had significantly longer and less efficient pathways within networks supporting verbal fluency (all t > 2.786, p < .006), highlighting the vulnerability of language to mTBI. Participants in whom a task-related network was relatively inefficient one week post injury were up to eight times more likely to have unfavorable cognitive outcome pertaining to that task. Our findings suggest that communication measures within task-related networks identify mTBI patients who are unlikely to develop persistent cognitive deficits after mTBI. Our approach and findings can help to stratify mTBI patients according to their expected need for follow-up and/or neurorehabilitation.

Brain changes: aerobic exercise for traumatic brain injury rehabilitation

Introduction

Traumatic Brain Injury (TBI) accounts for millions of hospitalizations and deaths worldwide. Aerobic exercise is an easily implementable, non-pharmacological intervention to treat TBI, however, there are no clear guidelines for how to best implement aerobic exercise treatment for TBI survivors across age and injury severity.

Methods

We conducted a PRISMA-ScR to examine research on exercise interventions following TBI in children, youth and adults, spanning mild to severe TBI. Three electronic databases (PubMed, PsycInfo, and Web of Science) were searched systematically by two authors, using keywords delineated from "Traumatic Brain Injury," "Aerobic Exercise," and "Intervention."

Results

Of the 415 papers originally identified from the search terms, 54 papers met the inclusion criteria and were included in this review. The papers were first grouped by participants' injury severity, and subdivided based on age at intervention, and time since injury where appropriate.

Discussion

Aerobic exercise is a promising intervention for adolescent and adult TBI survivors, regardless of injury severity. However, research examining the benefits of post-injury aerobic exercise for children and older adults is lacking.

The Additive Benefits of Aerobic Exercise and Cognitive Training Postconcussion: Current Clinical Concepts

Concussion induces the rapid onset of a short-lived neurophysiological disturbance that often results in autonomic nervous system dysfunction. This dysfunction affects both cardiovascular functioning and higher cognitive processing, inducing postconcussion clinical symptoms (somatic, cognitive, or emotional or a combination) and functional disturbances (impaired balance, cognition, and visual-vestibular performance). Current concussion rehabilitation paradigms using aerobic exercise may improve concussion symptoms. Additionally, cognitive training-focused rehabilitation interventions may enhance cognitive function postinjury. Though aerobic exercise and cognitive training-based concussion rehabilitation are successful independently, the multifaceted nature of concussion suggests the potential benefit of integrating both to improve concussion outcomes and clinician implementation. To support this clinical recommendation, we critiqued the existing research in which authors investigated aerobic exercise and cognitive training as postconcussion rehabilitation modalities, identified keys gaps in the literature, and proposed a practical clinical recommendation to integrate both modalities during concussion rehabilitation.

Altered longitudinal structural connectome in paediatric mild traumatic brain injury: an Advancing Concussion Assessment in Paediatrics study

Advanced diffusion-weighted imaging techniques have increased understanding of the neuropathology of paediatric mild traumatic brain injury (i.e. concussion). Most studies have examined discrete white-matter pathways, which may not capture the characteristically subtle, diffuse and heterogenous effects of paediatric concussion on brain microstructure. This study compared the structural connectome of children with concussion to those with mild orthopaedic injury to determine whether network metrics and their trajectories across time post-injury differentiate paediatric concussion from mild traumatic injury more generally. Data were drawn from of a large study of outcomes in paediatric concussion. Children aged 8-16.99 years were recruited from five paediatric emergency departments within 48 h of sustaining a concussion (n = 360; 56% male) or mild orthopaedic injury (n = 196; 62% male). A reliable change score was used to classify children with concussion into two groups: concussion with or without persistent symptoms. Children completed 3 T MRI at post-acute (2-33 days) and/or chronic (3 or 6 months, via random assignment) post-injury follow-ups. Diffusion-weighted images were used to calculate the diffusion tensor, conduct deterministic whole-brain fibre tractography and compute connectivity matrices in native (diffusion) space for 90 supratentorial regions. Weighted adjacency matrices were constructed using average fractional anisotropy and used to calculate global and local (regional) graph theory metrics. Linear mixed effects modelling was performed to compare groups, correcting for multiple comparisons. Groups did not differ in global network metrics. However, the clustering coefficient, betweenness centrality and efficiency of the insula, cingulate, parietal, occipital and subcortical regions differed among groups, with differences moderated by time (days) post-injury, biological sex and age at time of injury. Post-acute differences were minimal, whereas more robust alterations emerged at 3 and especially 6 months in children with concussion with persistent symptoms, albeit differently by sex and age. In the largest neuroimaging study to date, post-acute regional network metrics distinguished concussion from mild orthopaedic injury and predicted symptom recovery 1-month post-injury. Regional network parameters alterations were more robust and widespread at chronic timepoints than post-acutely after concussion. Results suggest that increased regional and local subnetwork segregation (modularity) and inefficiency occurs across time after concussion, emerging after post-concussive symptom resolve in most children. These differences persist up to 6 months after concussion, especially in children who showed persistent symptoms. While prognostic, the small to modest effect size of group differences and the moderating effects of sex likely would preclude effective clinical application in individual patients.

Diffusion-Weighted Imaging in Mild Traumatic Brain Injury: A Systematic Review of the Literature

There is evidence that diffusion-weighted imaging (DWI) is able to detect tissue alterations following mild traumatic brain injury (mTBI) that may not be observed on conventional neuroimaging; however, findings are often inconsistent between studies. This systematic review assesses patterns of differences in DWI metrics between those with and without a history of mTBI. A PubMed literature search was performed using relevant indexing terms for articles published prior to May 14, 2020. Findings were limited to human studies using DWI in mTBI. Articles were excluded if they were not full-length, did not contain original data, if they were case studies, pertained to military populations, had inadequate injury severity classification, or did not report post-injury interval. Findings were reported independently for four subgroups: acute/subacute pediatric mTBI, acute/subacute adult mTBI, chronic adult mTBI, and sport-related concussion, and all DWI acquisition and analysis methods used were included. Patterns of findings between studies were reported, along with strengths and weaknesses of the current state of the literature. Although heterogeneity of sample characteristics and study methods limited the consistency of findings, alterations in DWI metrics were most commonly reported in the corpus callosum, corona radiata, internal capsule, and long association pathways. Many acute/subacute pediatric studies reported higher FA and lower ADC or MD in various regions. In contrast, acute/subacute adult studies most commonly indicate lower FA within the context of higher MD and RD. In the chronic phase of recovery, FA may remain low, possibly indicating overall demyelination or Wallerian degeneration over time. Longitudinal studies, though limited, generally indicate at least a partial normalization of DWI metrics over time, which is often associated with functional improvement. We conclude that DWI is able to detect structural mTBI-related abnormalities that may persist over time, although future DWI research will benefit from larger samples, improved data analysis methods, standardized reporting, and increasing transparency.

A Scoping Review of Magnetic Resonance Modalities Used in Detection of Persistent Postconcussion Symptoms in Pediatric Populations

Up to 30% of youth with concussion experience PPCSs (PPCS) lasting 4 weeks or longer, and can significantly impact quality of life. Magnetic resonance imaging (MRI) has the potential to increase understanding of causal mechanisms underlying PPCS. However, there are no clear modalities to assist in detecting PPCS. This scoping review aims to synthesize findings on utilization of MRI among children and youth with PPCS, and summarize progress and limitations. Thirty-six studies were included from 4907 identified papers. Many studies used multiple modalities, including (1) structural (n = 27) such as T1-weighted imaging, diffusion weighted imaging, and susceptibility weighted imaging; and (2) functional (n = 23) such as functional MRI and perfusion-weighted imaging. Findings were heterogeneous among modalities and regions of interest, which warrants future reviews that report on the patterns and potential advancements in the field. Consideration of modalities that target PPCS prediction and sensitive modalities that can supplement a biopsychosocial approach to PPCS would benefit future research.

Intense long-term training impairs brain health compared with moderate exercise: Experimental evidence and mechanisms

The consequences of extremely intense long-term exercise for brain health remain unknown. We studied the effects of strenuous exercise on brain structure and function, its dose-response relationship, and mechanisms in a rat model of endurance training. Five-week-old male Wistar rats were assigned to moderate (MOD) or intense (INT) exercise or a sedentary (SED) group for 16 weeks. MOD rats showed the highest motivation and learning capacity in operant conditioning experiments; SED and INT presented similar results. In vivo MRI demonstrated enhanced global and regional connectivity efficiency and clustering as well as a higher cerebral blood flow (CBF) in MOD but not INT rats compared with SED. In the cortex, downregulation of oxidative phosphorylation complex IV and AMPK activation denoted mitochondrial dysfunction in INT rats. An imbalance in cortical antioxidant capacity was found between MOD and INT rats. The MOD group showed the lowest hippocampal brain-derived neurotrophic factor levels. The mRNA and protein levels of inflammatory markers were similar in all groups. In conclusion, strenuous long-term exercise yields a lesser improvement in learning ability than moderate exercise. Blunting of MOD-induced improvements in CBF and connectivity efficiency, accompanied by impaired mitochondrial energetics and, possibly, transient local oxidative stress, may underlie the findings in intensively trained rats.

Structural connectome differences in pediatric mild traumatic brain and orthopedic injury

Sophisticated network‐based approaches such as structural connectomics may help to detect a biomarker of mild traumatic brain injury (mTBI) in children. This study compared the structural connectome of children with mTBI or mild orthopedic injury (OI) to that of typically developing (TD) children. Children aged 8–16.99 years with mTBI (n = 83) or OI (n = 37) were recruited from the emergency department and completed 3T diffusion MRI 2–20 days postinjury. TD children (n = 39) were recruited from the community and completed diffusion MRI. Graph theory metrics were calculated for the binarized average fractional anisotropy among 90 regions. Multivariable linear regression and linear mixed effects models were used to compare groups, with covariates age, hemisphere, and sex, correcting for multiple comparisons. The two injury groups did not differ on graph theory metrics, but both differed from TD children in global metrics (local network efficiency: TD > OI, mTBI, d = 0.49; clustering coefficient: TD < OI, mTBI, d = 0.49) and regional metrics for the fusiform gyrus (lower degree centrality and nodal efficiency: TD > OI, mTBI, d = 0.80 to 0.96; characteristic path length: TD < OI, mTBI, d = −0.75 to −0.90) and in the superior and middle orbital frontal gyrus, paracentral lobule, insula, and thalamus (clustering coefficient: TD > OI, mTBI, d = 0.66 to 0.68). Both mTBI and OI demonstrated reduced global and regional network efficiency and segregation as compared to TD children. Findings suggest a general effect of childhood injury that could reflect pre‐ and postinjury factors that can alter brain structure. An OI group provides a more conservative comparison group than TD children for structural neuroimaging research in pediatric mTBI.

Application of neuropsychology and imaging to brain injury and use of the integrative cognitive rehabilitation psychotherapy model

BACKGROUND

An early approach to cognitive rehabilitation therapy (CRT) was developed based on A. R. Luria's theory of brain function. Expanding upon this approach, the Integrative Cognitive Rehabilitation Psychotherapy model (ICRP) was advanced.

OBJECTIVE

To describe the ICRP approach to treatment of clients post brain injury and provide a comprehensive list of evaluation tools to determine the client's abilities and needs. Finally, to provide a link between CRT and functional imaging studies designed to improve rehabilitation efforts.

METHODS

History of cognitive rehabilitation and neuropsychological testing is reviewed and description of cognitive, academic, psychiatric, and substance abuse tools are provided. Cognitive and emotional treatment techniques are fully described. Additionally, a method of determining the client's stage of recovery and pertinent functional imaging studies is detailed.

RESULTS

Authors have been able to provide a set of tools and techniques to use in comprehensive treatment of clients with brain injury.

CONCLUSIONS

Inclusive treatment which is outlined in the ICRP model is optimal for the client's recovery and return to a full and satisfying life post brain injury. The model provides a framework for neuropsychologists to integrate issues that tend to co-occur in clients living with brain injury into a unified treatment plan.

Implications of DTI in mild traumatic brain injury for detecting neurological recovery and predicting long-term behavioural outcome in paediatric and young population-a systematic review

PURPOSE

This systematic review was done with the aim to answer these three questions: 1) Is there any change in diffusion metrics in MRI-DTI sequences after mild traumatic brain injury in paediatric and young population?, 2) Is there any correlation of these changes in diffusion metrics with severity of post concussion symptoms?, 3) Is the change in diffusion metrics predictive of neurocognitive function or neurological recovery?

MATERIAL AND METHODS

Eligibility criteria- Mild TBI patients upto 22 years of age, MRI- DTI sequence done post injury, Outcome measurement with follow up at least for onemonth and articles published in English language only. Data sources- PubMed, EMBASE, CINAHL, Scopus and Cochrane RESULTS: Some studies show increased FA and some studies show decrease FA and few showed no change in white matter microstructure in mTBI patients and this depends on the duration of injury. Prediction of PCSs severity on the basis of changes in white matter microstructure showed inconsistent results. Radiological recovery in contrast to clinical recovery, is often delayed ranging from 6 months to 2-3 years. But change in diffusion metrics after mTBI is not definite predictive of neurocognitive outcomes.

CONCLUSION

Large, properly designed, multicentric studies with appropriate extracranial or orthopedic control and long follow up are needed to establish the use of DTIin mTBI for predicting behavioral outcome.

Topological Aberrance of Structural Brain Network Provides Quantitative Substrates of Post-Traumatic Brain Injury Attention Deficits in Children

Background: Traumatic brain injury (TBI)-induced attention deficits are among the most common long-term cognitive consequences in children. Most of the existing studies attempting to understand the neuropathological underpinnings of cognitive and behavioral impairments in TBI have utilized heterogeneous samples and resulted in inconsistent findings. The current research proposed to investigate topological properties of the structural brain network in children with TBI and their relationship with post-TBI attention problems in a more homogeneous subgroup of children who had severe post-TBI attention deficits (TBI-A). Materials and Methods: A total of 31 children with TBI-A and 35 group-matched controls were involved in the study. Diffusion tensor imaging-based probabilistic tractography and graph theoretical techniques were used to construct the structural brain network in each subject. Network topological properties were calculated in both global level and regional (nodal) level. Between-group comparisons among the topological network measures and analyses for searching brain-behavioral were all corrected for multiple comparisons using Bonferroni method. Results: Compared with controls, the TBI-A group showed significantly higher nodal local efficiency and nodal clustering coefficient in left inferior frontal gyrus and right transverse temporal gyrus, whereas significantly lower nodal clustering coefficient in left supramarginal gyrus and lower nodal local efficiency in left parahippocampal gyrus. The temporal lobe topological alterations were significantly associated with the post-TBI inattentive and hyperactive symptoms in the TBI-A group. Conclusion: The results suggest that TBI-related structural re-modularity in the white matter subnetworks associated with temporal lobe may play a critical role in the onset of severe post-TBI attention deficits in children. These findings provide valuable input for understanding the neurobiological substrates of post-TBI attention deficits, and have the potential to serve as quantitatively measurable criteria guiding the development of more timely and tailored strategies for diagnoses and treatments to the affected individuals. Impact statement This study provides a new insight into the neurobiological substrates associated with post-traumatic brain injury attention deficits (TBI-A) in children, by evaluating topological alterations of the structural brain network. The results demonstrated that relative to group-matched controls, the children with TBI-A had significantly altered nodal local efficiency and nodal clustering coefficient in temporal lobe, which strongly linked to elevated inattentive and hyperactive symptoms in the TBI-A group. These findings suggested that white matter structural re-modularity in subnetworks associated with temporal lobe may serve as quantitatively measurable biomarkers for early prediction and diagnosis of post-TBI attention deficits in children.

Physical Activity Interventions for Individuals With a Mild Traumatic Brain Injury:: A Scoping Review

OBJECTIVE

To document the characteristics, measured outcomes, and effectiveness of physical activity (PA) interventions designed to improve health-related outcomes in individuals with a mild traumatic brain injury (mTBI) to assist in rehabilitation quality improvement efforts of a TBI rehabilitation program.

METHODS

A scoping review following a 6-step iterative framework search across 5 databases (MEDLINE, CINAHL, PsycINFO, SPORTDiscuss, and EMBASE) and the gray literature (Google) was performed. Selected PA interventions were designed for individuals of all ages and any mechanism of injury (eg, sports-related and falls). Data were charted, collated, and summarized according to the Consensus on Exercise Reporting Template checklist and domains of the International Classification of Functioning, Disability and Health. Involvement of clinical experts ensured tailoring of the knowledge synthesis to meet clinical needs.

RESULTS

Thirty-five articles and 14 gray literature records were retained. Five types of PA interventions were identified with the majority being multimodal. Reporting of PA intervention characteristics was highly variable across studies; many details necessary for intervention replication are missing. Study outcomes focused primarily on improving body functions and symptoms of mTBI, and less frequently on activities, participation, and health-related quality of life. The methodological quality of studies varies.

CONCLUSIONS

Identified PA intervention types offer various management options for healthcare providers. PA interventions may improve a wide range of health-related outcomes supporting the inclusion of PA in the management of individuals of all ages with mTBI. Higher-quality research and better reporting about intervention characteristics is however needed.

Microstructural changes in the brain after long-term post-concussion symptoms: A randomized trial

A recent randomized controlled trial in young patients with long-term post-concussion symptoms showed that a novel behavioral intervention "Get going After concussIoN" is superior to enhanced usual care in terms of symptom reduction. It is unknown whether these interventional effects are associated with microstructural brain changes. The aim of this study was to examine whether diffusion-weighted MRI indices, which are sensitive to the interactions between cellular structures and water molecules' Brownian motion, respond differently to the interventions of the above-mentioned trial and whether such differences correlate with the improvement of post-concussion symptoms. Twenty-three patients from the intervention group (mean age 22.8, 18 females) and 19 patients from the control group (enhanced usual care) (mean age 23.9, 14 females) were enrolled. The primary outcome measure was the mean kurtosis tensor, which is sensitive to the microscopic complexity of brain tissue. The mean kurtosis tensor was significantly increased in the intervention group (p = 0.003) in the corpus callosum but not in the thalamus (p = 0.78) and the hippocampus (p = 0.34). An increase in mean kurtosis tensor in the corpus callosum tended to be associated with a reduction in symptoms, but this association did not reach significance (p = 0.059). Changes in diffusion tensor imaging metrics did not differ between intervention groups and were not associated with symptoms. The current study found different diffusion-weighted MRI responses from the microscopic cellular structures of the corpus callosum between patients receiving a novel behavioral intervention and patients receiving enhanced usual care. Correlations with improvement of post-concussion symptoms were not evident.

THE EFFECT OF AEROBIC EXERCISE ON ADOLESCENT ATHLETES POST-CONCUSSION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Adolescent athletes are experiencing an increased number of concussions. There is currently a debate within the medical community regarding the most effective and safe treatment approach for this population, post-concussion. Interventions currently range from cognitive and physical rest to various types of physical activity, including aerobic exercise. While there are systematic reviews that focus on rest as the main intervention, there are no other systematic reviews that focus on the effects of aerobic exercise on concussion recovery in adolescent athletes.

Purpose

The aim of this systematic review and meta-analysis was to investigate the effectiveness of aerobic exercise on concussion recovery for adolescent athletes compared to an alternate intervention.

Study Design

Systematic Review and Meta-Analysis.

Methods

A computer-based search (population: adolescent athletes with concussions, intervention: aerobic exercise, comparator: non-aerobic interventions, outcome: symptom severity and recovery time) was performed. Databases including PubMed, CINAHL, SPORTdiscus, ProQuest, and Scopus were searched up to December 2019 for randomized controlled trials published since 1965. A hand search of relevant articles and exploration of grey literature was also completed. Data were extracted for the following information: interventions prescribed, outcome measures, and overall results of the study. A meta-analysis was performed for aerobic interventions using standardized mean difference as the summary measure of effect.

Results

Five studies, which all held a moderate to low risk of bias according to the PEDro scale, met the inclusion criteria for this systematic review and meta-analysis. Overall results favored aerobic exercise for both acute and prolonged recovery symptoms as demonstrated by a decrease in symptom severity and improved recovery time. The meta-analysis revealed a moderate effect size in favor of the intervention group (SMD: 0.51, CI: 0.02, 0.81, p=0.00) when looking at the three outcome measures combined: Post-Concussion Symptom Scale, Post-Concussion Symptom Inventory, and recovery time.

Conclusion

The results of this systematic review and meta-analysis indicate that there is currently moderately significant evidence in support of implementing an aerobic exercise program for adolescent athletes with both acute and prolonged recovery concussion symptoms. Additional higher quality studies are needed to continue to study the effectiveness of aerobic exercise in post-concussion treatment of adolescents.

Level of Evidence

1a.

Neuroimaging in paediatric mild traumatic brain injury: a systematic review

Neuroimaging is being increasingly applied to the study of paediatric mild traumatic brain injury (mTBI) to uncover the neurobiological correlates of delayed recovery post-injury. The aims of this systematic review were to: (i) evaluate the neuroimaging research investigating neuropathology post-mTBI in children and adolescents from 0-18 years, (ii) assess the relationship between advanced neuroimaging abnormalities and PCS in children, (iii) assess the quality of the evidence by evaluating study methodology and reporting against best practice guidelines, and (iv) provide directions for future research. A literature search of MEDLINE, PsycINFO, EMBASE, and PubMed was conducted. Abstracts and titles were screened, followed by full review of remaining articles where specific eligibility criteria were applied. This systematic review identified 58 imaging studies which met criteria. Based on several factors including methodological heterogeneity and relatively small sample sizes, the literature currently provides insufficient evidence to draw meaningful conclusions about the relationship between MRI findings and clinical outcomes. Future research is needed which incorporates prospective, longitudinal designs, minimises potential confounds and utilises multimodal imaging techniques.

Central neurobiological effects of physical exercise in individuals with chronic musculoskeletal pain: a systematic review

OBJECTIVE

Primary objectives: to investigate the central neurobiological effects (using MRI) of physical exercise in individuals with chronic pain. Secondary objectives: (1) to investigate the associations between central changes and clinical outcomes and (2) to investigate whether different types and dosages of physical exercise exert different central changes.

DESIGN

Systematic review searching four electronic databases up to September 2018: AMED, CINAHL, Embase and MEDLINE. Two reviewers independently assessed the methodological quality of included studies using the Cochrane Collaboration's Risk of Bias in Non-Randomised Studies-I tool. A standardised extraction table was used for data extraction, which was performed by two reviewers.

INTERVENTIONS

Studies reporting any physical exercise intervention in any chronic musculoskeletal pain condition were included. Eligibility of 4011 records was screened independently by two reviewers, and four studies were included in the review.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome: any brain outcome assessed with any MR technique.

SECONDARY OUTCOMES

any self-reported clinical outcomes, and type and dosage of the exercise intervention.

RESULTS

All four studies had high risk of bias. There was heterogeneity between the brain areas studied and the types of exercise interventions delivered. All studies reported functional MRI changes in various brain areas following an exercise intervention. Insufficient data were available to conduct a meta-analysis or to answer the secondary aims.

CONCLUSIONS

Only a limited number of studies were available and all were at high risk of bias. None of the studies was randomised or included blinded assessment. Exercise may exert effects on brain neurobiology in people with chronic pain. Due to the high risk of bias, future studies should use a randomised study design. Investigation of morphological brain changes could be included.

PROSPERO REGISTRATION NUMBER

CRD42018108179.

Predicting Concussion Outcome by Integrating Finite Element Modeling and Network Analysis

Concussion is a significant public health problem affecting 1.6-2.4 million Americans annually. An alternative to reducing the burden of concussion is to reduce its incidence with improved protective equipment and injury mitigation systems. Finite element (FE) models of the brain response to blunt trauma are often used to estimate injury potential and can lead to improved helmet designs. However, these models have yet to incorporate how the patterns of brain connectivity disruption after impact affects the relay of information in the injured brain. Furthermore, FE brain models typically do not consider the differences in individual brain structural connectivities and their purported role in concussion risk. Here, we use graph theory techniques to integrate brain deformations predicted from FE modeling with measurements of network efficiency to identify brain regions whose connectivity characteristics may influence concussion risk. We computed maximum principal strain in 129 brain regions using head kinematics measured from 53 professional football impact reconstructions that included concussive and non-concussive cases. In parallel, using diffusion spectrum imaging data from 30 healthy subjects, we simulated structural lesioning of each of the same 129 brain regions. We simulated lesioning by removing each region one at a time along with all its connections. In turn, we computed the resultant change in global efficiency to identify regions important for network communication. We found that brain regions that deformed the most during an impact did not overlap with regions most important for network communication (Pearson's correlation, ρ = 0.07; p = 0.45). Despite this dissimilarity, we found that predicting concussion incidence was equally accurate when considering either areas of high strain or of high importance to global efficiency. Interestingly, accuracy for concussion prediction varied considerably across the 30 healthy connectomes. These results suggest that individual network structure is an important confounding variable in concussion prediction and that further investigation of its role may improve concussion prediction and lead to the development of more effective protective equipment.

Physical Therapy Evaluation and Treatment After Concussion/Mild Traumatic Brain Injury

Over the last decade, numerous concussion evidence-based clinical practice guidelines (CPGs), consensus statements, and clinical guidance documents have been published. These documents have typically focused on the diagnosis of concussion and medical management of individuals post concussion, but provide little specific guidance for physical therapy management of concussion and its associated impairments. Further, many of these guidance documents have targeted specific populations in specific care contexts. The primary purpose of this CPG is to provide a set of evidence-based recommendations for physical therapist management of the wide spectrum of patients who have experienced a concussive event. J Orthop Sports Phys Ther 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301.

The Role of Aerobic Exercise in Reducing Persistent Sport-related Concussion Symptoms

Aerobic exercise has received increasing attention in the scientific literature as a component of management for individuals who sustain a concussion. Because exercise training has been reported to reduce symptoms and improve function for those experiencing persistent postconcussion symptoms, it represents a potentially useful and clinically pragmatic rehabilitation technique. However, the specific exercise parameters that best facilitate recovery from concussion remain poorly defined and unclear. This review will provide a summary of the current understanding of the role of subsymptom exercise to improve outcomes after a concussion and will describe the exercise parameters that appear to be important. The latter will take into account the three pillars of exercise dose-frequency, duration, and intensity-to examine what is currently known. In addition, we identify important gaps in our knowledge of exercise as a treatment for those who develop persistent symptoms of concussion.

Pediatric Traumatic Brain Injury and Exercise Medicine: A Narrative Review

The multidisciplinary field of pediatric traumatic brain injury (TBI) and exercise medicine is of growing importance. There is active study into the diagnostic and therapeutic potential of exercise in pediatric TBI as well as the effects of TBI on postinjury fitness. With the evidence-based growing, a literature review can help establish the state of the science and inform future research. Therefore, the authors performed a narrative review (based on a search of 6 health sciences databases) to summarize evidence on pediatric TBI and cardiorespiratory fitness, muscular fitness and neuromotor control, and obesity. To date, studies related to cardiorespiratory fitness have centered on exercise tolerance and readiness to return to play, and indicate that protracted rest may not facilitate symptom recovery; this suggests a role for exercise in concussion management. Furthermore, strength and gait may be impaired following pediatric brain injury, and interventions designed to train these impairments may lead to their improvement. Pediatric brain injury can also lead to changes in body composition (which may be related to poorer cognitive recovery), but additional research is required to better understand such associations. This narrative review of pediatric TBI and exercise medicine can serve as a reference for researchers and clinicians alike.

Neurocognitive and Quality of Life Improvements Associated With Aerobic Training for Individuals With Persistent Symptoms After Mild Traumatic Brain Injury: Secondary Outcome Analysis of a Pilot Randomized Clinical Trial

Objective: To report secondary neurocognitive and quality of life outcomes for a pilot randomized clinical trial (RCT) of aerobic training for management of prolonged symptoms after a mild traumatic brain injury (mTBI) in adolescents. Setting: Outpatient research setting. Participants: Thirty adolescents between the ages of 12 and 17 years who sustained a mTBI and had between 4 and 16 weeks of persistent post-concussive symptoms. Design: Secondary outcome analysis of a partially masked RCT of sub-symptom exacerbation aerobic training compared with a full-body stretching program highlighting cognitive and quality of life outcomes. Main Measures: The secondary outcomes assessed included neurocognitive changes in fluid and crystallized age-adjusted cognition using the National Institutes of Health (NIH) toolbox and self and parent-reported total quality of life using the Pediatric Quality of Life Inventory. Results: Twenty-two percent of eligible participants enrolled in the trial. General linear models did not reveal statistically significant differences between groups. Within group analyses using paired t-tests demonstrated improvement in age-adjusted fluid cognition [t ₍₁₃₎ = 3.39, p = 0.005, Cohen's d = 0.61] and crystallized cognition [t ₍₁₃₎ = 2.63, p = 0.02, Cohen's d = 0.70] within the aerobic training group but no significant improvement within the stretching group. Paired t-tests demonstrated significant improvement in both self-reported and parent-reported total quality of life measures in the aerobic training group [self-report t ₍₁₃₎ = 3.51, p = 0.004, Cohen's d = 0.94; parent-report t ₍₁₃₎ = 6.5, p < 0.0001, Cohen's d = 1.80] and the stretching group [self-report t ₍₁₄₎ = 4.20, p = 0.0009, Cohen's d = 1.08; parent-report t ₍₁₄₎ = 4.06, p = 0.0012, Cohen's d = 1.045]. Conclusion: Quality of life improved significantly in both the aerobic exercise and stretching groups; however, this study suggests that only sub-symptom exacerbation aerobic training was potentially beneficial for neurocognitive recovery, particularly the fluid cognition subset in the NIH Toolbox. Limited sample size and variation in outcomes measures limited ability to detect between group differences. Future research should focus on developing larger studies to determine optimal timing post-injury and intensity of active rehabilitation to facilitate neurocognitive recovery and improve quality of life after mTBI. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02035579.

Bridging the gap: Mechanisms of plasticity and repair after pediatric TBI

Traumatic brain injury is the leading cause of death and disability in the United States, and may be associated with long lasting impairments into adulthood. The multitude of ongoing neurobiological processes that occur during brain maturation confer both considerable vulnerability to TBI but may also provide adaptability and potential for recovery. This review will examine and synthesize our current understanding of developmental neurobiology in the context of pediatric TBI. Delineating this biology will facilitate more targeted initial care, mechanism-based therapeutic interventions and better long-term prognostication and follow-up.

The structural connectome in traumatic brain injury: A meta-analysis of graph metrics

Although recent structural connectivity studies of traumatic brain injury (TBI) have used graph theory to evaluate alterations in global integration and functional segregation, pooled analysis is needed to examine the robust patterns of change in graph metrics across studies. Following a systematic search, 15 studies met the inclusion criteria for review. Of these, ten studies were included in a random-effects meta-analysis of global graph metrics, and subgroup analyses examined the confounding effects of severity and time since injury. The meta-analysis revealed significantly higher values of normalised clustering coefficient (gö=ö1.445, CI=[0.512, 2.378], pö=ö0.002) and longer characteristic path length (gö=ö0.514, CI=[0.190, 0.838], pö=ö0.002) in TBI patients compared with healthy controls. Our findings suggest that the TBI structural network has shifted away from the balanced small-world network towards a regular lattice. Therefore, these graph metrics may be useful markers of neurocognitive dysfunction in TBI. We conclude that the pattern of change revealed by our analysis should be used to guide hypothesis-driven research into the role of graph metrics as diagnostic and prognostic biomarkers.

Persistent Postconcussion Symptoms After Injury

: media-1vid110.1542/5828371885001PEDS-VA_2018-0939Video Abstract OBJECTIVES: We examined whether preinjury, demographic, and family factors influenced vulnerability to postconcussion symptoms (PCSs) persisting the year after mild traumatic brain injury (mTBI).

METHODS

Children with mTBI (n = 119), complicated mild traumatic brain injury (cmTBI) (n = 110), or orthopedic injury (OI) (n = 118), recruited from emergency departments, were enrolled in a prospective, longitudinal cohort study. Caregivers completed retrospective surveys to characterize preinjury demographic, child, and family characteristics. PCSs were assessed using a validated rating scale. With multivariable general linear models adjusted for preinjury symptoms, we examined predictors of PCSs 3, 6, and 12 months after injury in children ages 4 to 8, 9 to 12, and 13 to 15 years at injury. With logistic regression, we examined predictors of chronic PCSs 1 year after traumatic brain injury.

RESULTS

Postinjury somatic, emotional, cognitive, and fatigue PCSs were similar in the mTBI and cmTBI groups and significantly elevated compared with the OI group. PCS trajectories varied with age and sex. Adolescents had elevated PCSs that improved; young children had lower initial symptoms and less change. Despite similar preinjury PCSs, girls had elevated symptoms across all time points compared with boys. PCS vulnerability factors included female sex, adolescence, preinjury mood problems, lower income, and family discord. Social capital was a protective factor. PCSs persisted in 25% to 31% of the traumatic brain injury group and 18% of the OI group at 1 year postinjury. The odds of chronic PCSs were almost twice as high in girls as in boys and were >4 times higher in young children with cmTBI than in those with mTBI.

CONCLUSIONS

A significant minority of children with mTBI and OI have PCSs that persisted 1 year after injury.

Advanced biomarkers of pediatric mild traumatic brain injury: Progress and perils

There is growing public concern about neurodegenerative changes (e.g., Chronic Traumatic Encephalopathy) that may occur chronically following clinically apparent and clinically silent (i.e., sub-concussive blows) pediatric mild traumatic brain injury (pmTBI). However, there are currently no biomarkers that clinicians can use to objectively diagnose patients or predict those who may struggle to recover. Non-invasive neuroimaging, electrophysiological and neuromodulation biomarkers have promise for providing evidence of the so-called "invisible wounds" of pmTBI. Our systematic review, however, belies that notion, identifying a relative paucity of high-quality, clinically impactful, diagnostic or prognostic biomarker studies in the sub-acute injury phase (36 studies on unique samples in 28 years), with the majority focusing on adolescent pmTBI. Ultimately, well-powered longitudinal studies with appropriate control groups, as well as standardized and clearly-defined inclusion criteria (time post-injury, injury severity and past history) are needed to truly understand the complex pathophysiology that is hypothesized (i.e., still needs to be determined) to exist during the acute and sub-acute stages of pmTBI and may underlie post-concussive symptoms.

The Dynamics of Concussion: Mapping Pathophysiology, Persistence, and Recovery With Causal-Loop Diagramming

Despite increasing public awareness and a growing body of literature on the subject of concussion, or mild traumatic brain injury, an urgent need still exists for reliable diagnostic measures, clinical care guidelines, and effective treatments for the condition. Complexity and heterogeneity complicate research efforts and indicate the need for innovative approaches to synthesize current knowledge in order to improve clinical outcomes. Methods from the interdisciplinary field of systems science, including models of complex systems, have been increasingly applied to biomedical applications and show promise for generating insight for traumatic brain injury. The current study uses causal-loop diagramming to visualize relationships between factors influencing the pathophysiology and recovery trajectories of concussive injury, including persistence of symptoms and deficits. The primary output is a series of preliminary systems maps detailing feedback loops, intrinsic dynamics, exogenous drivers, and hubs across several scales, from micro-level cellular processes to social influences. Key system features, such as the role of specific restorative feedback processes and cross-scale connections, are examined and discussed in the context of recovery trajectories. This systems approach integrates research findings across disciplines and allows components to be considered in relation to larger system influences, which enables the identification of research gaps, supports classification efforts, and provides a framework for interdisciplinary collaboration and communication-all strides that would benefit diagnosis, prognosis, and treatment in the clinic.

Psychiatric Sequelae of Concussions

PURPOSE OF REVIEW

The purpose of this study was to review the frequency, risk factors, phenomenology, and course of prolonged recovery from concussion and of psychiatric sequelae in pediatric populations.

RECENT FINDINGS

Youth with prolonged recovery from concussions have higher initial symptoms, a history of multiple and/or recent concussions, and a tendency to somatization. Depression, post-traumatic stress disorder, behavioral disorders, and perhaps, suicidal behavior disorder are more common as both short- and longer-term sequelae of concussions. The weight of evidence supports a graduated return to function as compared to prolonged rest, which may actually impede recovery. For those with prolonged recovery, cognitive behavior therapy aimed at education about concussions, improving coping, problem-solving, sleep hygiene, and dealing with anxiety and depression provided in a collaborative care model is superior to usual care. Concussed youth have an increased risk of psychiatric symptoms and sleep disturbance that can be prevented or treated with proper management.