Concussion As a Multi-Scale Complex System: An Interdisciplinary Synthesis of Current Knowledge

Use of the concussion check protocol for concussion assessment in a female soccer team over two consecutive seasons in New Zealand

AIM

Address deficiencies in access to sports sideline medical care by using a Concussion Check Protocol (CCP) for non-medically-trained people.

METHOD

A prospective observational cohort study was undertaken on a single amateur female club-based soccer team over two consecutive years in New Zealand utilising a non-medically trained support person termed a Safety officer. CCP is an extension of the King-Devick test with features such as warning signs and symptoms of concussion built into the application. All players suspected of having a potential concussive injury were tested on the match sideline.

RESULTS

The study overall incidence of match-related concussions was 20.8 (95% CI: 11.8 to 36.6) per 1000 match-hrs, with mean missed-match duration of 31 (95% CI: 27.9 to 34.1) days. Twelve players over the study had a significantly slower post-injury KD (49.9 [44.3 to 64.1]s; χ2(1) = 11.0; p = 0.0009; z = -2.9; p = 0.0033; d = 0.30) and/or reported symptoms, compared with their own baseline (47.2 [44.3 to 64.1]s). CCP had an overall sensitivity of 100% (95% CI: 73.5% to 100.0%), specificity of 100% (95% CI: 69.2% to 100.0%) and positive predictive value (PPV) of 100% (84.6% to 100.0%).

CONCLUSION

Sideline use of CCP was undertaken successfully by non-medically trained people and provided a reliable platform for concussion identification.

The Bobath Clinical Reasoning Framework: A systems science approach to the complexity of neurodevelopmental conditions, including cerebral palsy

The current recommended developmental Bobath practice within the Bobath Clinical Reasoning Framework (BCRF) can be conceptualized using the lens of systems science, thereby providing a holistic perspective on the interrelatedness and interconnectedness of the variables associated with childhood-onset disability. The BCRF is defined as an in-depth clinical reasoning framework that can be applied to help understand the relationships between the domains of the International Classification of Functioning, Disability and Health, how those domains can be influenced, and how they impact each other. The BCRF is a transdisciplinary observational system and practical reasoning approach that results in an intervention plan. This provides a holistic understanding of the complexity of situations associated with disorders such as cerebral palsy (CP) and the basis for the lifelong management and habilitation of people living with neurological disorders. The clinical reasoning used by the BCRF draws on the important contextual factors of the individual and their social environment, primarily the family unit. It is rooted in an understanding of the interrelationships between typical and atypical development, pathophysiology (sensorimotor, cognitive, behavioural), and neuroscience, and the impact of these body structure and function constructs on activity and participation. The systems science model integral to the BCRF is a useful way forward in understanding and responding to the complexity of CP, the overarching goal being to optimize the lived experience of any individual in any context.

The role of the physiotherapist in concussion

In the last decade, concussion research has exploded in multiple fields of scientific research. This has helped to clarify what causes, influences, and perpetuates human concussion, and displays the integral role physiotherapists play in concussion management. In this article we discuss the latest research relevant to the key role of physiotherapy in concussion management. A narrative review of the literature on concussion was conducted. The current review analyses how concussion has influenced physiotherapy in several categories: assessment, treatment, management, research rigour and building the profile of the profession. Scientific concussion research has largely converged in support of the role of physiotherapists utilising specific components including: (1) autonomic, (2) cervicogenic, (3) vestibulo-ocular and (4) psychological approaches to management. Latest research supports the critical role of physiotherapy in concussion care in the assessment, management, and prevention of concussion with scope for further interdisciplinary collaborations.

Clinical implications

Concussion is complex. A basic mental health, Vestibular Ocular Motor Screening (VOMS) and four key components relating to concussion management (autonomic, cervicogenic, vestibular oculomotor, and psychological approaches to management) should be included in the undergraduate and postgraduate curriculum. This will aid clinical physiotherapists to support their patients. A call to advance more intradisciplinary physiotherapy teamwork should be encouraged as valuable knowledge sharing is potentially lost within the framework of 'specialisation'. If needed, the skills of a greater interdisciplinary team are imperative to facilitate patient management and recovery from this multi-faceted injury.

National Athletic Trainers' Association Bridge Statement: Management of Sport-Related Concussion

OBJECTIVE

To provide athletic trainers and team physicians with updated recommendations to the 2014 National Athletic Trainers' Association (NATA) concussion position statement regarding concussion management, specifically in the areas of education, assessment, prognostic factors, mental health, return to academics, physical activity, rest, treatment, and return to sport.

BACKGROUND

Athletic trainers have benefited from the 2 previous NATA position statements on concussion management, and although the most recent NATA position statement is a decade old, knowledge gains in the medical literature warrant updating several (but not all) recommendations. Furthermore, in various areas of the body of literature, current evidence now exists to address items not adequately addressed in the 2014 statement, necessitating the new recommendations. This document therefore serves as a bridge from the 2014 position statement to the current state of concussion evidence, recommendations from other organizations, and discrepancies between policy and practice.

RECOMMENDATIONS

These recommendations are intended to update the state of the evidence concerning the management of patients with sport-related concussion, specifically in the areas of education; assessment advances; prognostic recovery indicators; mental health considerations; academic considerations; and exercise, activity, and rehabilitation management strategies.

The need for systems thinking to advance Alzheimer's disease research

Despite extensive research efforts to mechanistically understand late-onset Alzheimer's disease (LOAD) and other complex mental health disorders, curative treatments remain elusive. We emphasize the multiscale multicausality inherent to LOAD, highlighting the interplay between interconnected pathophysiological processes and risk factors. Systems thinking methods, such as causal loop diagrams and systems dynamic models, offer powerful means to capture and study this complexity. Recent studies developed and validated a causal loop diagram and system dynamics model using multiple longitudinal data sets, enabling the simulation of personalized interventions on various modifiable risk factors in LOAD. The results indicate that targeting factors like sleep disturbance and depressive symptoms could be promising and yield synergistic benefits. Furthermore, personalized interventions showed significant potential, with top-ranked intervention strategies differing significantly across individuals. We argue that systems thinking approaches can open new prospects for multifactorial precision medicine. In future research, systems thinking may also guide structured, model-driven data collection on the multiple interactions in LOAD's complex multicausality, facilitating theory development and possibly resulting in effective prevention and treatment options.

Persistent MRI Findings Unique to Blast and Repetitive Mild TBI: Analysis of the CENC/LIMBIC Cohort Injury Characteristics

INTRODUCTION

MRI represents one of the clinical tools at the forefront of research efforts aimed at identifying diagnostic and prognostic biomarkers following traumatic brain injury (TBI). Both volumetric and diffusion MRI findings in mild TBI (mTBI) are mixed, making the findings difficult to interpret. As such, additional research is needed to continue to elucidate the relationship between the clinical features of mTBI and quantitative MRI measurements.

MATERIAL AND METHODS

Volumetric and diffusion imaging data in a sample of 976 veterans and service members from the Chronic Effects of Neurotrauma Consortium and now the Long-Term Impact of Military-Relevant Brain Injury Consortium observational study of the late effects of mTBI in combat with and without a history of mTBI were examined. A series of regression models with link functions appropriate for the model outcome were used to evaluate the relationships among imaging measures and clinical features of mTBI. Each model included acquisition site, participant sex, and age as covariates. Separate regression models were fit for each region of interest where said region was a predictor.

RESULTS

After controlling for multiple comparisons, no significant main effect was noted for comparisons between veterans and service members with and without a history of mTBI. However, blast-related mTBI were associated with volumetric reductions of several subregions of the corpus callosum compared to non-blast-related mTBI. Several volumetric (i.e., hippocampal subfields, etc.) and diffusion (i.e., corona radiata, superior longitudinal fasciculus, etc.) MRI findings were noted to be associated with an increased number of repetitive mTBIs versus.

CONCLUSIONS

In deployment-related mTBI, significant findings in this cohort were only observed when considering mTBI sub-groups (blast mechanism and total number/dose). Simply comparing healthy controls and those with a positive mTBI history is likely an oversimplification that may lead to non-significant findings, even in consortium analyses.

Le cadre de raisonnement clinique Bobath: un modèle de science des systèmes pour aborder la complexité des troubles neurodéveloppementaux, y compris la paralysie cérébrale

La pratique Bobath actuelle telle qu'elle est recommandée dans le cadre du Bobath Clinical Reasoning Framework (BCRF) se base sur une application clinique de la science des systèmes. Elle offre une perspective holistique des relations entre les variables qui sont associées à l'apparition d'un handicap chez l'enfant. Le BCRF est un cadre de raisonnement clinique qui peut aider à comprendre les relations entre les domaines de la Classification Internationale du Fonctionnement, du Handicap et de la Santé. C'est un système d'observation transdisciplinaire de raisonnement pratique qui vise à proposer un plan d'intervention. Plus généralement, le BCRF permet une compréhension holistique de la complexité des situations associées à des troubles tels que la paralysie cérébrale et indique des choix d'adaptation et de prise en charge tout au long de la vie des personnes vivant avec des troubles neurologiques. Ce raisonnement clinique se base sur les facteurs contextuels importants de l'individu et de son environnement social, principalement la cellule familiale, et sur une compréhension des relations entre le développement typique et atypique, la physiopathologie (sensorimotrice, cognitive, comportementale) et les neurosciences, ainsi que sur l'impact des fonctions et des structures corporelles sur les activités et la participation. Le modèle de la science des systèmes du BCRF permet d'aborder la complexité de la paralysie cérébrale, avec l'objectif global d'optimiser l'expérience vécue par chaque individu dans chaque contexte.

O Quadro de Raciocínio Clínico Bobath: Uma abordagem de ciência de sistemas para a complexidade das condições do neurodesenvolvimento, incluindo a paralisia cerebral

Esta revisão descreve um modelo de prática pediátrica recomendada do Bobath, o Quadro de Raciocínio Clínico Bobath (QRCB), e explica como esse conhecimento contribui para a área de habilitação em distúrbios pediátricos. A ciência de sistemas proporciona uma nova maneira de concetualizar a paralisia cerebral como uma condição complexa. Ela foi aplicada ao QRCB para ilustrar uma perspetiva holística sobre a inter-relação e interconexão das variáveis associadas à PC. O modelo de ciência de sistemas adotado pelo QRCB é uma forma promissora de construir uma estrutura abrangente que engloba a complexidade da PC e possibilitará pesquisas mais robustas.

CONNECTing Concussion Care with Research Across Ontario

Common data elements (CDEs) for concussion, as established by international bodies, are not being widely used in Ontario, resulting in significant variability in the data being assessed and collected across clinics. CDEs support standardization of care as well as large-scale data sharing for high impact research. A collaborative network - Concussion Ontario Network: Neuroinformatics to Enhance Clinical care and Translation (CONNECT) - comprised of health care professionals, researchers, members from advocacy groups, and patients was formed to establish and implement CDEs for concussion care and research. While the seeds have been planted and initial effectiveness demonstrated, future challenges exist.

Disrupted Maturation of White Matter Microstructure After Concussion Is Associated With Internalizing Behavior Scores in Female Children

BACKGROUND

Some children who experience concussions, particularly females, develop long-lasting emotional and behavioral problems. Establishing the potential contribution of preexisting behavioral problems and disrupted white matter maturation has been challenging due to a lack of preinjury data.

METHODS

From the Adolescent Brain Cognitive Development cohort, 239 (90 female) children age 12.1 ± 0.6 years who experienced a concussion after study entry at 10.0 ± 0.6 years were compared to 6438 (3245 female) children without head injuries who were age 9.9 ± 0.6 years at baseline and 12.0 ± 0.6 years at follow-up. The Child Behavior Checklist was used to assess internalizing and externalizing behavior at study entry and follow-up. In the children with magnetic resonance imaging data available (concussion n = 134, comparison n = 3520), deep and superficial white matter was characterized by neurite density from restriction spectrum image modeling of diffusion magnetic resonance imaging. Longitudinal ComBat harmonization removed scanner effects. Linear regressions modeled 1) behavior problems at follow-up controlling for baseline behavior, 2) impact of concussion on white matter maturation, and 3) contribution of deviations in white matter maturation to postconcussion behavior problems.

RESULTS

Only female children with concussion had higher internalizing behavior problem scores. The youngest children with concussion showed less change in superficial white matter neurite density over 2 years than children with no concussion. In females with concussion, less change in superficial white matter neurite density was correlated with increased internalizing behavior problem scores.

CONCLUSIONS

Concussions in female children are associated with emotional problems beyond preinjury levels. Injury to superficial white matter may contribute to persistent internalizing behavior problems in females.

El marco de razonamiento clínico de Bobath: Un modelo de ciencia de sistemas para abordar la complejidad de los trastornos del neurodesarrollo incluida la parálisis cerebral

La actual práctica de desarrollo Bobath recomendada dentro del Marco de Razonamiento Clínico Bobath (BCRF) puede conceptualizarse utilizando la visión de la ciencia de los sistemas. Proporciona, así, una perspectiva holística de la interrelación e interconexión de las variables asociadas con la discapacidad aparecida durante la infancia. El BCRF se define como un marco exhaustivo de razonamiento clínico que puede aplicarse para ayudar a comprender las relaciones entre los dominios de la Clasificación Internacional del Funcionamiento, de la Discapacidad y de la Salud, cómo se puede influir en esos dominios y cómo influyen entre sí. El BCRF es un sistema de observación transdisciplinario y de razonamiento práctico que da lugar a un plan de intervención. Esto proporciona una comprensión holística de la complexidad de las situaciones asociadas a trastornos como la parálisis cerebral (PC) y la base para la gestión y habilitación a lo largo de la vida de personas que viven con trastornos neurológicos. El razonamiento clínico utilizado por el BCRF se basa en los importantes factores contextuales del individuo y su entorno social, principalmente la unidad familiar. Se basa en la comprensión de las interrelaciones entre el desarrollo típico y atípico, la fisiopatología (sensoriomotora, cognitiva, conductual) y la neurociencia, así como el impacto de funciones y estructuras corporales sobre la actividad y la participación. El modelo de ciencia de sistemas del BCRF es una forma útil de comprender y responder a la complejidad de la parálisis cerebral, con el objetivo global de optimizar la experiencia vivida de todo individuo en cualquier contexto.

Prolonged Disability following Re-Exposure after Complete Recovery from Aerotoxic Syndrome: A Case Report

Aerotoxic syndrome is a rarely recognized and poorly defined illness resulting from exposure to products of oil combustion in commercial aircraft bleed air systems. The pathophysiology of this syndrome is not well understood. A 42-year-old male pilot developed duty-limiting symptoms consistent with aerotoxic syndrome following exposure to airline cabin fumes and recurrence of symptoms following re-exposure despite apparent full recovery from the initial exposure event. Given his persistent symptoms and concern for immediate debilitation/incapacitation if re-exposed, the pilot was deemed medically unqualified for return to commercial piloting duties and a disability determination was made. Consideration of aerotoxic syndrome in aircrew members with unusual or episodic symptoms of neuro/cognitive dysfunction is essential for further characterizing this occupational illness, guiding medical management, and understanding its impact on aviation workforce health.

Understanding the Sociocognitive Determinants Underlying Intentions to Exercise for Postconcussion Symptom Relief: An Application of the Theory of Planned Behavior

CONTEXT

This study investigated individual sociocognitive factors from the theory of planned behavior and their relationship to exercise for postconcussion recovery.

DESIGN AND METHODS

Four hundred and fifty-nine Australian adults, two-thirds of whom had no concussion history (66%), completed an online survey of their beliefs and attitudes toward exercise for postconcussion recovery. Secondary questions evaluated program design features that could affect engagement (eg, session frequency).

RESULTS

Structured equation modeling found that subjective norms were the strongest significant predictor of intention to participate in exercise for postconcussion recovery. Perceived behavioral control was also a significant predictor of intention to participate but to a lesser extent. Attitude did not predict participation intention. The design features identified as key were personalization and being supervised during the program.

CONCLUSIONS

This study found that people's intention to participate in a program of exercise postconcussion recovery is shaped by individual psychological factors and identified program design features that could be adjusted for increased engagement. Program success could be maximized through strategies such as supporting individuals to have a stronger sense of control over their participation through the choice of session timing or frequency and harnessing the influence of significant others via supportive messaging from key professionals.

Recovery after traumatic brain injury: An integrative review of the role of social factors on postinjury outcomes

This research is an integrative review of the literature on social factors in TBI outcomes. It examines how such factors have been framed in TBI models, the social experience of people post-injury, and the evidence for effective social interventions. Evidence suggests that even when physical functioning has improved after injury, there is a lingering social distress that leaves individuals isolated and functionally impaired. A novel hypothesis is proposed to explain why these difficulties persist. This hypothesis draws from existing biopsychosocial models of TBI recovery, including those prominent in neuropsychology. It is argued that the social component of several TBI outcome models is too narrowly defined. This potentially has the effect of focusing efforts on the individual and their social skills or abilities as opposed to the seeking improvements at the level of the community. Evidence for and against this hypothesis is considered. This evaluation supports the idea that TBI outcomes are subject to a wider range of post injury social factors than is typically recognized, and that these factors are dynamic rather than static. Inspired by this hypothesis, this review proposes that social interventions for TBI should be adjusted to suit the stage of recovery.

A psychometric evaluation of a new social subscale for the Common Misconceptions about Traumatic Brain Injury (CM-TBI) questionnaire: toward the CM-TBI-II

OBJECTIVE

Existing TBI misconception measures are critiqued for failing to measure postinjury social experiences. This study developed a social subscale for the Common Misconceptions about TBI (CM-TBI) questionnaire for use in the general public.

METHODS

Seven experts independently review items drawn from the literature. Shortlisted items were administered online to 158 adults (aged ≥18 years; 51% postschool educated; 60% no TBI experience), the CM-TBI, and a measure of construct validity (a published TBI-adaptation of the Community Attitudes Towards the Mentally Ill; CAMI-TBI). One week later, the new items were redeployed (n = 46).

RESULTS

Expert review and iterative correlations identified a 10-item social subscale (internal consistency, test-retest reliability, α's>.80). When added to the CM-TBI (ie. CM-TBI-II), the internal consistency was .71. The social subscale was significantly correlated with CAMI-TBI measures (p's <.05, r's > .3). There was no significant difference on the social subscale for education subgroups (school vs post-school, p = 0.056) or previous TBI experience; but there was a difference for the CM-TBI-II (post-school>school; Cohen's d = 7.83, large effect).

CONCLUSION

This study found strong preliminary psychometric support for a new social subscale, administered as the CM-TBI-II. This subscale shows promise as a measure of misconceptions about social functioning post-TBI. The CM-TBI-II could support evaluations of programs aiming to improve social engagement and community participation for people with TBI.

Examining the interdisciplinary approach for treatment of persistent post-concussion symptoms in adults: a systematic review

BACKGROUND

The objective of this review is to examine the evidence for the interdisciplinary approach in treatment of persistent post-concussion symptoms in adults.

METHODS

This systematic literature search was undertaken according to the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA) guidelines. Five electronic databases were searched: CINAHL, Informit, ProQuest, PubMed and Scopus. After screening and quality assessment, the review included six studies published in English and peer-reviewed journals, between 2011 and 2021 to return contemporary evidence.

RESULTS

The results revealed that there was significant variation between measures used and the timing of the pre- and post-treatment assessment. The studies found an interdisciplinary approach to be beneficial, however, the challenges of inherent heterogeneity, lack of clarity for definitions and diagnosis, and mixed results were apparent. The interdisciplinary interventions applied in all identified studies were found to reduce post-concussion symptoms across the symptom subtypes: headache/migraine, vestibular, cognitive, ocular motor and anxiety/mood.

CONCLUSIONS

The results demonstrated evidence for a reduction in persistent post-concussion symptoms following interdisciplinary intervention. This evidence will inform health services, clinicians, sports administrators and researchers with regard to concussion clinic and rehabilitation team design and service delivery.

Recommendations for Medical Discharge Documentation and Academic Supports for University Students Recovering From Concussion

OBJECTIVE

This study sought to (1) collate the experiences of university students with concussion history and academic stakeholders through interviews and (2) develop concussion management recommendations for institutions of higher learning using a multidisciplinary Delphi procedure.

SETTING

Remote semistructured interviews and online surveys.

PARTICIPANTS

The first aim of this study included undergraduate university students with concussion history who did not participate in varsity athletics ( n = 21; 57.1% female), as well as academic faculty/staff with experience assisting university students with their postconcussion academic needs ( n = 7; 71.4% female). The second aim enrolled 22 participants (54.5% female) to serve on the Delphi panel including 9 clinicians, 8 researchers, and 5 academic faculty/staff.

DESIGN

An exploratory-sequential mixed-methods approach.

MAIN MEASURES

Semistructured interviews were conducted to unveil barriers regarding the return-to-learn (RTL) process after concussion, with emergent themes serving as a general framework for the Delphi procedure. Panelists participated in 3 stages of a modified Delphi process beginning with a series of open-ended questions regarding postconcussion management in higher education. The second stage included anonymous ratings of the recommendations, followed by an opportunity to review and/or modify responses based on the group's consensus.

RESULTS

The results from the semistructured interviews indicated students felt supported by their instructors; however, academic faculty/staff lacked information on appropriate academic supports and/or pathways to facilitate the RTL process. Of the original 67 statements, 39 achieved consensus (58.2%) upon cessation of the Delphi procedure across 3 main categories: recommendations for discharge documentation (21 statements), guidelines to facilitate a multidisciplinary RTL approach (10 statements), and processes to obtain academic supports for students who require them after concussion (8 statements).

CONCLUSIONS

These findings serve as a basis for future policy in higher education to standardize RTL processes for students who may need academic supports following concussion.

Benefits of a 12-Week Non-Drug "Brain Fitness Program" for Patients with Attention-Deficit/Hyperactive Disorder, Post-Concussion Syndrome, or Memory Loss

Background

Non-pharmacologic interventions can potentially improve cognitive function, sleep, and/or mood in patients with attention-deficit/hyperactive disorder (ADHD), post-concussion syndrome (PCS), or memory loss.

Objective

We evaluated the benefits of a brain rehabilitation program in an outpatient neurology practice that consists of targeted cognitive training, lifestyle coaching, and electroencephalography (EEG)-based neurofeedback, twice weekly (90 minutes each), for 12 weeks.

Methods

223 child and adult patients were included: 71 patients with ADHD, 88 with PCS, and 64 with memory loss (mild cognitive impairment or subjective cognitive decline). Patients underwent a complete neurocognitive evaluation, including tests for Verbal Memory, Complex Attention, Processing Speed, Executive Functioning, and Neurocognition Index. They completed questionnaires about sleep, mood, diet, exercise, anxiety levels, and depression-as well as underwent quantitative EEG-at the beginning and the end of the program.

Results

Pre-post test score comparison demonstrated that all patient subgroups experienced statistically significant improvements on most measures, especially the PCS subgroup, which experienced significant score improvement on all measures tested (p≤0.0011; d_z≥0.36). After completing the program, 60% to 90% of patients scored higher on cognitive tests and reported having fewer cognitive and emotional symptoms. The largest effect size for pre-post score change was improved executive functioning in all subgroups (ADHD d_z= 0.86; PCS d_z= 0.83; memory d_z= 1.09).

Conclusion

This study demonstrates that a multimodal brain rehabilitation program can have benefits for patients with ADHD, PCS, or memory loss and supports further clinical trials in this field.

Factors related to adverse long-term outcomes after mild traumatic brain injury in children: a scoping review

OBJECTIVE

To identify demographic, premorbid and injury-related factors, or biomarkers associated with long-term (≥3 months) adverse outcomes in children after mild traumatic brain injury (mTBI).

DESIGN

Scoping review of literature.

PATIENTS

Children and adolescents with mTBI.

RISK FACTORS

Any demographic, premorbid and injury-related factors, or biomarkers were included. We excluded genetic and treatment-related factors.

MAIN OUTCOME MEASURES

Postconcussion syndrome (PCS), recovery.

RESULTS

Seventy-three publications were included, reporting 12 long-term adverse outcomes, including PCS in 12 studies and recovery in 29 studies. Additional outcomes studied were symptom scores/severity (n=22), quality of life (n=9) and cognitive function (n=9). Forty-nine risk factors were identified across studies. Risk factors most often assessed were sex (n=28), followed by age (n=23), injury mechanism = (n=22) and prior mTBI (n=18). The influence of these and other risk factors on outcomes of mTBI were inconsistent across the reviewed literature.

CONCLUSIONS

The most researched risk factors are sex, age and mechanism of injury, but their effects have been estimated inconsistently and did not show a clear pattern. The most studied outcomes are recovery patterns and symptom severity. However, these may not be the most important outcomes for clinicians and patients. Future primary studies in this area should focus on patient-important outcomes. Population-based prospective studies are needed that address prespecified hypotheses on the relationship of risk factors with given outcomes to enable reliable prediction of long-term adverse outcomes for childhood mTBI.

Inflammatory cytokines associated with mild traumatic brain injury and clinical outcomes: a systematic review and meta-analysis

Mild traumatic brain injuries (mTBIs) trigger a neuroinflammatory response, which leads to perturbations in the levels of inflammatory cytokines, resulting in a distinctive profile. A systematic review and meta-analysis were conducted to synthesize data related to levels of inflammatory cytokines in patients with mTBI. The electronic databases EMBASE, MEDLINE, and PUBMED were searched from January 2014 to December 12, 2021. A total of 5,138 articles were screened using a systematic approach based on the PRISMA and R-AMSTAR guidelines. Of these articles, 174 were selected for full-text review and 26 were included in the final analysis. The results of this study demonstrate that within 24 hours, patients with mTBI have significantly higher levels of Interleukin-6 (IL-6), Interleukin-1 Receptor Antagonist (IL-1RA), and Interferon-γ (IFN-γ) in blood, compared to healthy controls in majority of the included studies. Similarly one week following the injury, patients with mTBI have higher circulatory levels of Monocyte Chemoattractant Protein-1/C-C Motif Chemokine Ligand 2 (MCP-1/CCL2), compared to healthy controls in majority of the included studies. The results of the meta-analysis also confirmed these findings by demonstrating significantly elevated blood levels of IL-6, MCP-1/CCL2, and Interleukin-1 beta (IL-1β) in the mTBI population compared to healthy controls (p < 0.0001), particularly in the acute stages (<7 days). Furthermore, it was found that IL-6, Tumor Necrosis Factor-alpha (TNF-α), IL-1RA, IL-10, and MCP-1/CCL2 were associated with poor clinical outcomes following the mTBI. Finally, this research highlights the lack of consensus in the methodology of mTBI studies that measure inflammatory cytokines in the blood, and also provides direction for future mTBI research.

Combined Neurocognitive and Exercise Tolerance Testing Improves Objectivity of Buffalo Concussion Treadmill Test

CONTEXT

The Buffalo Concussion Treadmill Test (BCTT) is a standard assessment of exercise tolerance utilized for exercise prescription following concussion and to inform decisions regarding return to play. One limitation of the BCTT is that interpretation of test results is dependent on individuals' self-report of symptom exacerbation with exertion. Symptoms following concussion are significantly underreported or unreported. Combining objective neurocognitive assessment with exercise tolerance testing may enable clinicians to objectively identify those requiring further assessment or rehabilitation before return to play. The purpose of this study was to investigate how performance on a neurocognitive assessment battery is affected by provocative exercise testing.

DESIGN

Prospective cohort study, pretest/posttest.

METHODS

A total of 30 participants included 13 women (43.3%), age 23.4 (1.93) years, height 173.56 (10) cm, weight 77.35 (16.3) kg, and 11 (36.7%) with history of concussion. All participants completed a neurocognitive assessment battery, including the Stroop Test and standardized assessments of working memory, attention, and information processing speed/accuracy in single-task (seated position) and dual-task conditions (walking on a treadmill at 2.0 miles per hour). The neurocognitive assessment battery was performed at baseline and after the standard BCTT test protocol.

RESULTS

BCTT: Average percentage of heart rate maximum (%HRmax) = 93.97% (4.8%); average maximum rating of perceived exertion = 18.6 (1.5). Time-based performance in single-task and dual-task conditions significantly improved from baseline (P < .05) following maximal exercise testing on the BCTT for the following neurocognitive assessments: concentration-reverse digits, Stroop congruent, and Stroop incongruent.

CONCLUSIONS

Healthy participants demonstrated improvements across multiple domains of neurocognitive performance following the exercise tolerance testing on the BCTT. Understanding normal responses in neurocognitive performance for healthy individuals following exercise tolerance testing may allow clinicians to more objectively monitor the trajectory of recovery following sports-related concussion.

A Systematic Review of ASL Perfusion MRI in Mild TBI

Mild traumatic brain injury (mTBI) is a major public health concern. Cerebrovascular alterations play a significant role in the evolution of injury sequelae and in the process of post-traumatic brain repair. Arterial spin labeling (ASL) is an advanced perfusion magnetic resonance imaging technique that permits noninvasive quantification of cerebral blood flow (CBF). This is the first systematic review of ASL research findings in patients with mTBI. Our approach followed the American Academy of Neurology (AAN) and PRISMA guidelines. We searched Ovid/MEDLINE, Web of Science, Scopus, and the Cochrane Index for relevant articles published as of February 20, 2020. Full-text results were combined into Rayyan software for further evaluation. Data extraction, including risk of bias ratings, was performed using American Academy of Neurology's four-tiered classification scheme. Twenty-three articles met inclusion criteria comprising data on up to 566 mTBI patients and 654 control subjects. Of the 23 studies, 18 reported some type of regional CBF abnormality in mTBI patients at rest or during a cognitive task, with more findings of decreased than increased CBF. The evidence supports the conclusion that mTBI likely causes ASL-derived CBF anomalies. However, synthesis of findings was challenging due to substantial methodological variations across studies and few studies with low risk of bias. Thus, larger-scale prospective cohort studies are needed to more definitively chart the course of CBF changes in humans after mTBI and to understand how individual difference factors contribute to post-injury CBF changes.

Factor structure of the modified Rivermead Post-concussion Symptoms Questionnaire (mRPQ): an exploratory analysis with healthy adult simulators

OBJECTIVE

Persistent postconcussion symptoms (PPCS) are challenging to diagnose. An improved diagnostic process could consider typical and atypical postconcussion symptoms. This study examined the structure of a modified Rivermead Post-concussion Symptoms Questionnaire (mRPQ) with both symptom types.

METHOD

298 adult volunteers were randomized into groups: honest responders, mild traumatic brain injury (mTBI) simulators (MS), and biased mTBI simulators (BMS). Both mTBI simulating groups were coached about mTBI and primed about the simulation context (compensation evaluation). The BMS group was also encouraged to bias (exaggerate) symptoms. The participants completed an online battery of tests, including the mRPQ.

RESULTS

An exploratory factor analysis of the mRPQ (full sample) revealed a three-factor solution, including a separate dimension for atypical symptoms (all item loadings >0.45, ~4% of explained variance). The overall and group analyses of the standard RPQ items (typical symptoms) found a one- or two-factor solution, as did the analyses of atypical symptoms.

CONCLUSIONS

Consistent with prior RPQ research, a unidimensional or bifactor structure was measurable from standard RPQ symptoms. Whilst this study did not find support for domain-level symptom scores for either typical or atypical symptoms, the findings support the use of an overall atypical symptoms score.

Subtle impairments of perceptual-motor function and well-being are detectable among military cadets and college athletes with self-reported history of concussion

Introduction

A lack of obvious long-term effects of concussion on standard clinical measures of behavioral performance capabilities does not preclude the existence of subtle neural processing impairments that appear to be linked to elevated risk for subsequent concussion occurrence, and which may be associated with greater susceptibility to progressive neurodegenerative processes. The purpose of this observational cohort study was to assess virtual reality motor response variability and survey responses as possible indicators of suboptimal brain function among military cadets and college athletes with self-reported history of concussion (HxC).

Methods

The cohort comprised 75 college students (20.7 ± 2.1 years): 39 Reserve Officer Training Corp (ROTC) military cadets (10 female), 16 football players, and 20 wrestlers; HxC self-reported by 20 (29.2 ± 27.1 months prior, range: 3-96). A virtual reality (VR) test involving 40 lunging/reaching responses to horizontally moving dots (filled/congruent: same direction; open/incongruent: opposite direction) was administered, along with the Sport Fitness and Wellness Index (SFWI) survey. VR Dispersion (standard deviation of 12 T-scores for neck, upper extremity, and lower extremity responses to congruent vs. incongruent stimuli originating from central vs. peripheral locations) and SFWI response patterns were the primary outcomes of interest.

Results

Logistic regression modeling of VR Dispersion (range: 1.5-21.8), SFWI (range: 44-100), and an interaction between them provided 81% HxC classification accuracy (Model χ ²[2] = 26.03, p < .001; Hosmer & Lemeshow χ ²[8] = 1.86, p = .967; Nagelkerke R ²= .427; Area Under Curve = .841, 95% CI: .734, .948). Binary modeling that included VR Dispersion ≥3.2 and SFWI ≤86 demonstrated 75% sensitivity and 86% specificity with both factors positive (Odds Ratio = 17.6, 95% CI: 5.0, 62.1).

Discussion/Conclusion

Detection of subtle indicators of altered brain processes that might otherwise remain unrecognized is clearly important for both short-term and long-term clinical management of concussion. Inconsistency among neck, upper extremity, and lower extremity responses to different types of moving visual stimuli, along with survey responses suggesting suboptimal well-being, merit further investigation as possible clinical indicators of persisting effects of concussion that might prove to be modifiable.

Validating the modified Rivermead Post-concussion Symptoms Questionnaire (mRPQ)

OBJECTIVE

Response distortions in the reporting of postconcussion symptoms can occur for many reasons. The Rivermead Post-concussion Symptoms Questionnaire (RPQ) was recently modified to include an embedded symptom validity indicator to test for atypical symptoms. The present study used a simulation design to investigate the psychometric properties of the modified RPQ (mRPQ).

METHOD

298 adult volunteers were randomised into three groups: honest responding (Controls, C) who reported actual, current symptoms; mild traumatic brain injury (mTBI) simulators (MS) who role played being injured, and; biased mTBI simulators (BMS) who role played being injured and were asked to bias (exaggerate) their response. The MS and BMS participants received instructions to support the simulation. All participants completed the mRPQ and a modified Neurobehavioral Symptom Inventory (mNSI).

RESULTS

A 2 × 3 mixed ANOVA with one within-group variable (Symptom type: Standard or Atypical) and one between-group variable (Instruction type: C, MS, BMS) found a significant two-way interaction (p < .05, ηp2 = .08).

CONCLUSIONS

The BMS group had score elevations for both standard and atypical postconcussion symptoms; therefore, both symptom types should be considered when evaluating for biased responding. The mRPQ has promising psychometric properties and should be further developed.

Multi-Modal Neurorehabilitation for Persisting Post-Concussion Symptoms

Treatment of the chronic sequela that persist after a mild traumatic brain injury has been challenging with limited efficacy. The aim of this work was to report outcomes obtained from persons who met the criteria of persisting post-concussive symptoms (PPCS), utilizing a novel combination of modalities in a structured neurorehabilitation program. This work was designed as a retrospective, pre-post chart review of objective and subjective measures collected from 62 outpatients with PPCS a mean of 2.2 years post-injury, before and after a multi-modal 5-day treatment protocol. The subjective outcome measure was the 27-item modified Graded Symptom Checklist (mGSC). Objective outcome measures were motor speed/reaction time, coordination, cognitive processing, visual acuity, and vestibular function. Interventions included non-invasive neuromodulation, neuromuscular re-education exercises, gaze stabilization exercises, orthoptic exercises, cognitive training, therapeutic exercises, and single/multi-axis rotation therapy. Pre-post differences in measures were analyzed using the Wilcoxon signed-rank test, with effect size determined by the rank-biserial correlation coefficient. Pre-post treatment comparisons for the subjective mGSC overall, combined symptom measures, individual components of the mGSC, and cluster scores significantly improved for all items. Moderate strength relationships were observed for the mGSC composite score, number of symptoms, average symptom score, feeling in a "fog," "don't feel right," irritability, and physical, cognitive, and affective cluster scores. Objective symptom assessment significantly improved for trail making, processing speed, reaction time, visual acuity, and Standardized Assessment of Concussion. Patients suffering from PPCS ∼2 years after injury may have significant benefits with some moderate effect sizes from an intensive, multi-modal neurorehabilitation program.

Flexibility of in vitro cortical circuits influences resilience from microtrauma

Background

Small clusters comprising hundreds to thousands of neurons are an important level of brain architecture that correlates single neuronal properties to fulfill brain function, but the specific mechanisms through which this scaling occurs are not well understood. In this study, we developed an in vitro experimental platform of small neuronal circuits (islands) to probe the importance of structural properties for their development, physiology, and response to microtrauma.

Methods

Primary cortical neurons were plated on a substrate patterned to promote attachment in clusters of hundreds of cells (islands), transduced with GCaMP6f, allowed to mature until 10-13 days in vitro (DIV), and monitored with Ca²⁺ as a non-invasive proxy for electrical activity. We adjusted two structural factors-island size and cellular density-to evaluate their role in guiding spontaneous activity and network formation in neuronal islands.

Results

We found cellular density, but not island size, regulates of circuit activity and network function in this system. Low cellular density islands can achieve many states of activity, while high cellular density biases islands towards a limited regime characterized by low rates of activity and high synchronization, a property we summarized as "flexibility." The injury severity required for an island to lose activity in 50% of its population was significantly higher in low-density, high flexibility islands.

Conclusion

Together, these studies demonstrate flexible living cortical circuits are more resilient to microtrauma, providing the first evidence that initial circuit state may be a key factor to consider when evaluating the consequences of trauma to the cortex.

Neuromorphic-Based Neuroprostheses for Brain Rewiring: State-of-the-Art and Perspectives in Neuroengineering

Neuroprostheses are neuroengineering devices that have an interface with the nervous system and supplement or substitute functionality in people with disabilities. In the collective imagination, neuroprostheses are mostly used to restore sensory or motor capabilities, but in recent years, new devices directly acting at the brain level have been proposed. In order to design the next-generation of neuroprosthetic devices for brain repair, we foresee the increasing exploitation of closed-loop systems enabled with neuromorphic elements due to their intrinsic energy efficiency, their capability to perform real-time data processing, and of mimicking neurobiological computation for an improved synergy between the technological and biological counterparts. In this manuscript, after providing definitions of key concepts, we reviewed the first exploitation of a real-time hardware neuromorphic prosthesis to restore the bidirectional communication between two neuronal populations in vitro. Starting from that 'case-study', we provide perspectives on the technological improvements for real-time interfacing and processing of neural signals and their potential usage for novel in vitro and in vivo experimental designs. The development of innovative neuroprosthetics for translational purposes is also presented and discussed. In our understanding, the pursuit of neuromorphic-based closed-loop neuroprostheses may spur the development of novel powerful technologies, such as 'brain-prostheses', capable of rewiring and/or substituting the injured nervous system.

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.

Analyzing pericytes under mild traumatic brain injury using 3D cultures and dielectric elastomer actuators

Traumatic brain injury (TBI) is defined as brain damage due to an external force that negatively impacts brain function. Up to 90% of all TBI are considered in the mild severity range (mTBI) but there is still no therapeutic solution available. Therefore, further understanding of the mTBI pathology is required. To assist with this understanding, we developed a cell injury device (CID) based on a dielectric elastomer actuator (DEA), which is capable of modeling mTBI via injuring cultured cells with mechanical stretching. Our injury model is the first to use patient-derived brain pericyte cells, which are ubiquitous cells in the brain involved in injury response. Pericytes were cultured in our CIDs and mechanically strained up to 40%, and by at least 20%, prior to gene expression analysis. Our injury model is a platform capable of culturing and stretching primary human brain pericytes. The heterogeneous response in gene expression changes in our result may suggest that the genes implicated in pathological changes after mTBI could be a patient-dependent response, but requires further validation. The results of this study demonstrate that our CID is a suitable tool for simulating mTBI as an in vitro stretch injury model, that is sensitive enough to induce responses from primary human brain pericytes due to mechanical impacts.

System dynamics modeling for traumatic brain injury: Mini-review of applications

Traumatic brain injury (TBI) is a highly complex phenomenon involving a cascade of disruptions across biomechanical, neurochemical, neurological, cognitive, emotional, and social systems. Researchers and clinicians urgently need a rigorous conceptualization of brain injury that encompasses nonlinear and mutually causal relations among the factors involved, as well as sources of individual variation in recovery trajectories. System dynamics, an approach from systems science, has been used for decades in fields such as management and ecology to model nonlinear feedback dynamics in complex systems. In this mini-review, we summarize some recent uses of this approach to better understand acute injury mechanisms, recovery dynamics, and care delivery for TBI. We conclude that diagram-based approaches like causal-loop diagramming have the potential to support the development of a shared paradigm of TBI that incorporates social support aspects of recovery. When developed using adequate data from large-scale studies, simulation modeling presents opportunities for improving individualized treatment and care delivery.

Heart Rate Variability as a Reliable Biomarker Following Concussion: A Critically Appraised Topic

CLINICAL SCENARIO

Recent systematic reviews show conflicting information regarding the effect of concussion on cardiac autonomic function. Controlled aerobic exercise is the most popular intervention for those recovering from a concussion. There is a gap in the literature supporting the utility of objective metrics during exertional return to play protocols and rehabilitation.

CLINICAL QUESTION

Can heart rate variability (HRV) during physical exertion be a reliable biomarker over time for those who suffered a sport-related concussion?

SUMMARY OF KEY FINDINGS

A literature search produced 3 studies relevant to the clinical question. One, a prospective-matched control group cohort study, reported disturbances in HRV during physical exertion in those with a history of concussion, and identified persistent HRV dysfunction after resolution of subjective complaints, return to play, and with multiple concussive events. Second, a cross-sectional cohort study found an HRV difference in those with and without a history of concussion and in HRV related to age and sex. Finally, the prospective longitudinal case-control cohort study did not find sex or age differences in HRV and concluded that, although postconcussion HRV improved as time passed, resting HRV was not as clinically meaningful as HRV during exertional activities.

CLINICAL BOTTOM LINE

There is emerging evidence to support the use of HRV as an observable biomarker, over time, of autonomic function during physical exertion following a sport-related concussion. However, the meaningfulness of HRV data is not fully understood and the utility seems individualized to the level of athlete, age, and sex and, therefore, cannot be generalizable. In order to be more clinically meaningful and to assist with current clinical decision making regarding RTP, a preinjury baseline assessment would be beneficial as an individualized reference for baseline comparison.

STRENGTH OF RECOMMENDATION

Although HRV is not fully understood, currently, there is grade B evidence to support the use of individualized baseline exertional HRV data as comparative objective metric to assess the autonomic nervous system function, over time, following a concussive event.

Adolescent and Parent Perceptions of the Impact of Concussion/mTBI on Family Functioning and Activity Levels in Recovery

OBJECTIVE

To explore adolescent and parent perceptions of the impact of a concussion/mild traumatic brain injury (mTBI) on family functioning and activity levels in the first 4 weeks of recovery.

SETTING

Outpatient research setting.

PARTICIPANTS

Twenty-seven adolescents (aged of 13-17 years) within 1 week of a concussion/mTBI and a parent/guardian were enrolled in the study.

DESIGN

Prospective ecological study with qualitative, semistructured interviews.

MAIN MEASURES

Adolescents reported symptoms electronically every 2 days for 28 days via the Post-Concussion Symptom Inventory. Semistructured interviews were completed with each adolescent-parent dyad at the end of the 28-day period. Interview questions focused on perceptions of recovery progress and study procedures.

RESULTS

Symptom trajectories were variable across participants. Three main themes emerged from thematic analysis, including: (1) disruption of routines and activities, (2) injury management considerations, and (3) positive and negative influential factors (eg, school and coach support, timing of injury, and recovery expectations). Results highlighted nuances of recovery challenges that families specifically face and help emphasize the potential benefits of shared decision-making and where more guidance would be appreciated such as more specific self-management of symptoms and physical activity reintegration strategies.

CONCLUSIONS

Study findings support a shared decision-making approach with the identified themes as potential topics to help consider social and environmental influences on recovery. The themes presented in the results could be topics emphasized during intake and follow-up visit processes to help guide plans of care and return-to-activity decisions.

Blink duration is increased in concussed youth athletes: a validity study using eye tracking in male youth and adult athletes of selected contact sports

OBJECTIVE

Diagnosing a sports-related concussion (SRC) remains challenging, and research into diagnostic tools is limited. This study investigated whether selected eye tracking variables would be a valid tool to diagnose and monitor SRC in adult and youth participants in selected contact sports, such as Rugby Union (rugby) and football (soccer).

METHODS

This prospective cohort study, with 70 concussed and 92 non-concussed adult and youth athletes, assessed the validity of five previously selected eye tracking variables for SRC diagnostics and management. The performance between concussed and age-matched control (non-concussed) athletes, as well as between three successive testing sessions in the concussed athletes were compared. Self-paced saccade count in adult group; blink duration in the memory-guided saccade and sinusoidal smooth pursuit tasks, proportion of antisaccade errors, and gain of diagonal smooth pursuit in the youth group were assessed.

RESULTS

The youth concussed group had higher blink duration in the fast memory-guided saccades task (p = 0.001, η2 = 0.17) and a tendency for higher blink duration in the sinusoidal smooth pursuit task (p = 0.016, η2 = 0.06) compared to the youth control group. In both tasks the blink duration in the concussed youth group decreased from session 1 to session 2 by 24% and 18%, accordingly, although statistical significance was not reached. The concussed adult group demonstrated a lower number of self-paced saccades compared to controls (p = 0.05, η2 = 0.09), which gradually increased, with the largest difference between session 1 and session 3 (p = 0.02).

CONCLUSIONS

Blink duration in youth athletes holds promise as a valid metric for concussion diagnostics and monitoring. It is recommended to focus future studies on comparing eye tracking performance within the same concussed athletes over time rather than comparing them to healthy controls.

Postconcussion discharge advice does not improve concussion knowledge in a community sample

OBJECTIVE

Poor concussion knowledge in the community has been linked to reduced injury identification. This study investigated if concussion knowledge could be improved by providing standard postinjury advice (written brochure).

METHODS

This study was a prospective, controlled study, with random allocation of 199 Australian adults to receive either a concussion information (CI, n=101), or non-CI (n=98). All participants completed the Rosenbaum Concussion Knowledge and Attitudes Survey on three occasions: pre-education and posteducation, and 1 week later.

RESULTS

A 2 (condition) × 3 (occasion) mixed analysis of variance with concussion knowledge as the dependent variable did not find a statistically significant interaction (p>0.05). This result was unchanged: (1) with the covariate addition of background education and; (2) in a subgroup analysis (individuals with initially 'low' self-rated knowledge). Some key misconceptions about concussion were identified.

CONCLUSION

The community knowledge of concussion was not significantly improved by the concussion advice. Since injury recognition relies ton an extent on community knowledge, the identified misconceptions should be addressed. This could occur via public health messaging. In clinical settings and for future research, the next steps should also include regular updating of concussion information to keep pace with advances in the field.

Multi-tract multi-symptom relationships in pediatric concussion

Background

The heterogeneity of white matter damage and symptoms in concussion has been identified as a major obstacle to therapeutic innovation. In contrast, most diffusion MRI (dMRI) studies on concussion have traditionally relied on group-comparison approaches that average out heterogeneity. To leverage, rather than average out, concussion heterogeneity, we combined dMRI and multivariate statistics to characterize multi-tract multi-symptom relationships.

Methods

Using cross-sectional data from 306 previously concussed children aged 9-10 from the Adolescent Brain Cognitive Development Study, we built connectomes weighted by classical and emerging diffusion measures. These measures were combined into two informative indices, the first representing microstructural complexity, the second representing axonal density. We deployed pattern-learning algorithms to jointly decompose these connectivity features and 19 symptom measures.

Results

Early multi-tract multi-symptom pairs explained the most covariance and represented broad symptom categories, such as a general problems pair, or a pair representing all cognitive symptoms, and implicated more distributed networks of white matter tracts. Further pairs represented more specific symptom combinations, such as a pair representing attention problems exclusively, and were associated with more localized white matter abnormalities. Symptom representation was not systematically related to tract representation across pairs. Sleep problems were implicated across most pairs, but were related to different connections across these pairs. Expression of multi-tract features was not driven by sociodemographic and injury-related variables, as well as by clinical subgroups defined by the presence of ADHD. Analyses performed on a replication dataset showed consistent results.

Conclusions

Using a double-multivariate approach, we identified clinically-informative, cross-demographic multi-tract multi-symptom relationships. These results suggest that rather than clear one-to-one symptom-connectivity disturbances, concussions may be characterized by subtypes of symptom/connectivity relationships. The symptom/connectivity relationships identified in multi-tract multi-symptom pairs were not apparent in single-tract/single-symptom analyses. Future studies aiming to better understand connectivity/symptom relationships should take into account multi-tract multi-symptom heterogeneity.

Funding

Financial support for this work came from a Vanier Canada Graduate Scholarship from the Canadian Institutes of Health Research (G.I.G.), an Ontario Graduate Scholarship (S.S.), a Restracomp Research Fellowship provided by the Hospital for Sick Children (S.S.), an Institutional Research Chair in Neuroinformatics (M.D.), as well as a Natural Sciences and Engineering Research Council CREATE grant (M.D.).

Vestibular/Ocular Motor Screening is Independently Associated With Concussion Symptom Severity in Youths

OBJECTIVE

To examine the independent contributions of the Vestibular/Ocular Motor Screening (VOMS) to concussion symptom severity in youths while controlling for computerized neurocognitive screening performance, demographics, and medical history.

STUDY DESIGN

Cross-sectional.

SETTING

Concussion specialty clinic.

PARTICIPANTS

A retrospective review of 278 concussed youths clinical charts resulted in a total of 158 participants (16.5 ± 2.8 years, 46.8% women, 4.3 ± 3.3 days post-injury) when exclusionary criteria (ie, neurological or substance use disorders, age >21, >14 days since injury, and missing/incomplete data) were applied.

INDEPENDENT VARIABLES

Vestibular/Ocular Motor Screening items and computerized neurocognitive test scores.

MAIN OUTCOME MEASURES

Standardized postconcussion symptom scale scores.

RESULTS

At the univariate level, all VOMS items were positively associated with concussion symptom severity at small to medium effect sizes (r range 0.26-0.42). Women and individuals with a concussion history and/or Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder diagnosis reported higher VOMS item scores (Ps < 0.10). In a multiple hierarchical regression, the contribution of VOMS item scores was significant and explained 9.6% of the variance in concussion symptom severity after adjustment for sex, baseline VOMS symptom ratings, and ImPACT scores [F(6, 141) = 3.90, P = 0.001]. Vertical saccades (b = 2.22, P = 0.003) and vertical vestibulo-ocular reflex (VOR; b = -1.46, P = 0.004) VOMS items significantly contributed to concussion symptom severity in the multivariable model.

CONCLUSIONS

Findings from this study provide support for the independent contributions of the VOMS items, particularly vertical saccades and vertical VOR, to acute concussion symptom severity in youths. Further work is warranted for a comparison of the VOMS to the full gold standard of concussion testing (ie, clinical interview, physical examination, balance testing, and neurocognitive assessment).

A Novel Approach to Assessment of Perceptual-Motor Efficiency and Training-Induced Improvement in the Performance Capabilities of Elite Athletes

Standard clinical assessments of mild traumatic brain injury are inadequate to detect subtle abnormalities that can be revealed by sophisticated diagnostic technology. An association has been observed between sport-related concussion (SRC) and subsequent musculoskeletal injury, but the underlying neurophysiological mechanism is not currently understood. A cohort of 16 elite athletes (10 male, 6 female), which included nine individuals who reported a history of SRC (5 male, 4 female) that occurred between 4 months and 8 years earlier, volunteered to participate in a 12-session program for assessment and training of perceptual-motor efficiency. Performance metrics derived from single- and dual-task whole-body lateral and diagonal reactive movements to virtual reality targets in left and right directions were analyzed separately and combined in various ways to create composite representations of global function. Intra-individual variability across performance domains demonstrated very good SRC history classification accuracy for the earliest 3-session phase of the program (Reaction Time Dispersion AUC = 0.841; Deceleration Dispersion AUC = 0.810; Reaction Time Discrepancy AUC = 0.825, Deceleration Discrepancy AUC = 0.794). Good earliest phase discrimination was also found for Composite Asymmetry between left and right movement directions (AUC = 0.778) and Excursion Average distance beyond the minimal body displacement necessary for virtual target deactivation (AUC = 0.730). Sensitivity derived from Youden's Index for the 6 global factors ranged from 67 to 89% and an identical specificity value of 86% for all of them. Median values demonstrated substantial improvement from the first 3-session phase to the last 3-session phase for Composite Asymmetry and Excursion Average. The results suggest that a Composite Asymmetry value ≥ 0.15 and an Excursion Average value ≥ 7 m, provide reasonable qualitative approximations for clinical identification of suboptimal perceptual-motor performance. Despite acknowledged study limitations, the findings support a hypothesized relationship between whole-body reactive agility performance and functional connectivity among brain networks subserving sensory perception, cognitive decision-making, and motor execution. A complex systems approach appears to perform better than traditional data analysis methods for detection of subtle perceptual-motor impairment, which has the potential to advance both clinical management of SRC and training for performance enhancement.

Understanding the impact of exposure to adverse socioeconomic conditions on chronic stress from a complexity science perspective

BACKGROUND

Chronic stress increases chronic disease risk and may underlie the association between exposure to adverse socioeconomic conditions and adverse health outcomes. The relationship between exposure to such conditions and chronic stress is complex due to feedback loops between stressor exposure and psychological processes, encompassing different temporal (acute stress response to repeated exposure over the life course) and spatial (biological/psychological/social) scales. We examined the mechanisms underlying the relationship between exposure to adverse socioeconomic conditions and chronic stress from a complexity science perspective, focusing on amplifying feedback loops across different scales.

METHODS

We developed a causal loop diagram (CLD) to interpret available evidence from this perspective. The CLD was drafted by an interdisciplinary group of researchers. Evidence from literature was used to confirm/contest the variables and causal links included in the conceptual framework and refine their conceptualisation. Our findings were evaluated by eight independent researchers.

RESULTS

Adverse socioeconomic conditions imply an accumulation of stressors and increase the likelihood of exposure to uncontrollable childhood and life course stressors. Repetition of such stressors may activate mechanisms that can affect coping resources and coping strategies and stimulate appraisal of subsequent stressors as uncontrollable. We identified five feedback loops describing these mechanisms: (1) progressive deterioration of access to coping resources because of repeated insolvability of stressors; (2) perception of stressors as uncontrollable due to learned helplessness; (3) tax on cognitive bandwidth caused by stress; (4) stimulation of problem avoidance to provide relief from the stress response and free up cognitive bandwidth; and (5) susceptibility to appraising stimuli as stressors against a background of stress.

CONCLUSIONS

Taking a complexity science perspective reveals that exposure to adverse socioeconomic conditions implies recurrent stressor exposure which impacts chronic stress via amplifying feedback loops that together could be conceptualised as one vicious cycle. This means that in order for individual-level psychological interventions to be effective, the context of exposure to adverse socioeconomic conditions also needs to be addressed.

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.

Multi-modal magnetic resonance imaging in a mouse model of concussion

This data collection contains Magnetic Resonance Imaging (MRI) data, including structural, diffusion, stimulus-evoked, and resting-state functional MRI and behavioural assessment results, including acute post-impact Loss-of-Righting Reflex time and acute, subacute, and longer-term Neural Severity Score, and Open Field Behaviour obtained from a mouse model of concussion. Four cohorts with 43 3-4 months old male mice in total were used: Sham (n = 14, n = 6 day 2, n = 3 day 7, n = 5 day 14), concussion day 2 (CON 2; n = 9), concussion day 7 (CON 7; n = 10), concussion day 14 (CON 14; n = 10). The data collection contains the aforementioned MRI data in compressed NIFTI format, data sheets on animal's backgrounds and behavioural outcomes and is made publicly available from a data repository. The available data are intended to facility cross-study comparisons, meta-analysis, and science reproducibility.

Oculomotor Deficits and Symptom Severity Are Associated With Poorer Dynamic Mobility in Chronic Mild Traumatic Brain Injury

Oculomotor deficits, vestibular impairments, and persistent symptoms are common after a mild traumatic brain injury (mTBI); however, the relationship between visual-vestibular deficits, symptom severity, and dynamic mobility tasks is unclear. Twenty-three individuals (mean age 55.7 ± 9.3 years) with persistent symptoms after mTBI, who were between 3 months to 2 years post-injury were compared with 23 age and sex-matched controls. Oculomotor deficits [depth perception, near-point convergence, baseline visual acuity (BLVA), perception time], vestibular deficits (dynamic visual acuity in the pitch and yaw planes), dynamic mobility measured by the Functional Gait Assessment (FGA), and symptoms measured by the Post-Concussion Symptom Scale (PCSS) and Dizziness Handicap Inventory (DHI) were compared between groups. Participants with mTBI had poorer performance on the FGA (p < 0.001), higher symptom severity on the PCSS (p < 0.001), and higher DHI scores (p < 0.001) compared to controls. Significant differences were seen on specific items of the FGA between individuals with mTBI and controls during walking with horizontal head turns (p = 0.002), walking with vertical head tilts (p < 0.001), walking with eyes closed (p = 0.003), and stair climbing (p = 0.001). FGA performance was correlated with weeks since concussion (r = −0.67, p < 0.001), depth perception (r = −0.5348, p < 0.001), near point convergence (r = −0.4717, p = 0.001), baseline visual acuity (r = −0.4435, p = 0.002); as well as with symptoms on the PCSS (r = −0.668, p < 0.001), and DHI (r = −0.811, p < 0.001). Dynamic balance deficits persist in chronic mTBI and may be addressed using multifaceted rehabilitation strategies to address oculomotor dysfunction, post-concussion symptoms, and perception of handicap due to dizziness.

Editors' Foreword: Knowledge and Skill Competencies for Speech-Language Pathology Management of Concussion

[Figure: see text].

Evolving Science to Inform Emerging Concussion Practices

Purpose This article describes two concussion models built on the current state of science that help illustrate the complicated interactions among the multiple factors that drive concussion symptoms. Consideration of these models remind practitioners, including speech-language pathologists, to attend to factors that increase the risk of patients developing prolonged symptoms, as well as attend to symptoms that result from various interactions and may differentially respond to specific treatments. In particular, the models encourage personalized or precision medicine and the implementation of targeted, coordinated therapies.

Interprofessional Collaborative Management of Postconcussion Cognitive Symptoms

Purpose The purpose of this clinical focus article is to illustrate an interprofessional cognitive rehabilitation approach. Invited experts representing physical medicine and rehabilitation, clinical neuropsychology/rehabilitation psychology, registered nurse care coordination, and speech-language pathology share viewpoints from their discipline to engage in collaborative interventions with the goal of enhancing treatment outcomes. Conclusions Treating the multifactorial symptoms of concussion requires expertise from an interdisciplinary team (IDT) of professionals, contributing unique perspectives and providing integrative services to optimize rehabilitation outcomes for patients. Speech-language pathologists serve an important role on IDTs to deliver personalized, targeted therapies for prolonged or persistent postconcussion cognitive impairment.

Sleep quality in the chronic stage of concussion is associated with poorer recovery: A systematic review

Background

Recovery from a concussion varies based on a multitude of factors. One such factor is sleep disturbances. In our prior review, it was observed that in the acute phase, sleep disturbances are predictive of poor outcomes following a concussion. The literature gap remains on how sleep in the chronic phase of recovery affects outcomes.

Objective

To examine the association between sleep quality during the chronic stage of concussion and post-concussion outcomes. Literature Survey: Literature searches were performed during 1 July to 1 August 2019 in selected databases along with searching grey literature. Out of the 733 results, 702 references were reviewed after duplicate removal.

Methods

Three reviewers independently reviewed and consented on abstracts meeting eligibility criteria ( n = 35). The full-text articles were assessed independently by two reviewers. Consensus was achieved, leaving four articles. Relevant data from each study was extracted using a standard data-extraction table. Quality appraisal was conducted to assess potential bias and the quality of articles.

Results

One study included children (18–60 months) and three studies included adolescents and/or adults (ranging 12–35 years). The association between sleep and cognition (two studies), physical activity (one study), and emotion symptoms (one study) was examined. Sleep quality was associated with decreased cognition and emotional symptoms, but not with meeting physical activity guidelines six months post-concussion injury.

Conclusions

The heterogeneity in age of participants and outcomes across studies and limited number of included studies made interpretations difficult. Future studies may consider if addressing sleep quality following concussion will improve outcomes.

Effects of CranioSacral therapy upon symptoms of post-acute concussion and Post-Concussion Syndrome: A pilot study

OBJECTIVE

The purpose of this study was to investigate the utilization of CranioSacral Therapy (CST) in patients with Post-Concussion Syndrome (PCS) and capture patient-reported perceptions of clinical outcomes of lived treatment experiences.

DESIGN

Two-part, longitudinal study conducted through a chart review of target group, followed by a Patient-reported Treatment Outcome Survey (PTOS).

PARTICIPANTS

A convenience sample of 212 patients with a historical incidence of head trauma not requiring hospitalization was obtained through medical records department dating back ten years. Inclusion criteria for further chart review (n = 67) was determined by identifying patients with a confirmed concussion directly correlated with presenting symptoms and for which CST was specifically sought as a treatment option. Demographics and patient-determined treatment duration data were analyzed by comparison groups extensively suggested in existing literature: Recovery time since injury as either Post-acute concussion (<6 months) or Post-Concussion Syndrome (PCS) (≥6 months); Athletes (A) or Non-athletes (NA); and traditional gender. Final PTOS group criteria was determined by eliminating confounding issues reporting (n = 47): (A, n = 24 and NA, n = 23).

RESULTS

Quantitative data was analyzed via Numerical Analysis, and qualitative data was analyzed via Inductive Content Analysis. Symptoms reported in all charts as well as in the PTOS were consistent with identified PCS subtypes. Utilization of CST revealed that most patients determined the treatment effect upon concussion symptoms within 1-3 sessions. Nearly twice as many sessions were attended in the PCS than post-acute groups. Referral sources, studied for a perspective on local concussion after-care discharge planning, ranged from professional to personal recommendation or self-discovery. A majority of patients met goals of reducing post-acute or PCS as reasons cited by self-determined change-in-status or discharge from service. Patients were asked to indicate on the PTOS which pre- and post-treatment symptoms were helped or not helped by this particular intervention.

CONCLUSIONS

Patient-reported changes of PCS symptoms is critical when evaluating treatment options. CST is an experiential treatment that addresses subjective levels of dysfunction, thus it is the patient deciding the value of an intervention. A sizable portion of patients in all groups reported a positive effect upon their symptoms by CST. Patients indicated personal meaning to CST through their utilization of multiple sessions. A high percentage indicated the likelihood of referring others with PCS for CST. Of the 212 patient charts first studied, the 145 not meeting inclusion criteria suggest some chronic conditions may present as long-term effects of older head injuries. CST is a low-risk, conservative treatment option for PCS sub-types worthy of further clinical study.