Preliminary evidence of reduced brain network activation in patients with post-traumatic migraine following concussion

Post-traumatic headache pathophysiology in paediatric concussion: A systematic review

Post-traumatic headache (PTH) represents the most common acute and persistent symptom following concussion in children, yet the underlying pathophysiology remains unclear. This systematic review sought to: (i) rigorously examine the current evidence of PTH pathophysiology in paediatric concussion (0-18 years), (ii) assess the quality of evidence, and (iii) provide directions for future research in accordance with PRISMA guidelines. Eligible studies (n = 19) totalling 1214 concussion participants investigated cerebrovascular function (n = 6), white matter integrity (n = 3), functional connectivity (n = 3), electrophysiology (n = 1), neurometabolics (n = 2), biological fluid markers (n = 4), vestibular and oculomotor function (n = 4); two studies used a multi-modal approach. Majority of studies were rated as fair quality (90%) and Level 3 evidence (84%). The true underlying mechanisms of PTH following paediatric concussion remain unclear. Overall quality of the available evidence is generally weak with a fair risk of bias and characterised by relative scarcity and lack of specificity of PTH pathophysiology. Future research is required to rigorously isolate pathophysiology specific to PTH with strict adherence to clinical definitions and standardised measurement tools of PTH.

Brain functional connectivity in children with a mild traumatic brain injury: A scoping review

INTRODUCTION

The occurrence of mild traumatic brain injury(mTBI) is estimated at 0,2-0,3% cases annually. Following a mTBI, some children experience persistent symptoms, and functional connectivity(FC) changes may be implicated. However, characteristics of FC have not been widely described in this population. This scoping review aimed to identify and understand the impacts of mTBI on EEG-measured FC in children, provide an overview of the available literature, detail analysis techniques, and describe gaps in the research.

METHODS

PubMed, Web of Science, Medline, Embase, ProQuest and CINAHL were searched up to June 25, 2023, with the terms child, mTBI, EEG, FC, and their synonyms. Ten studies were identified.

RESULTS

Five studies reported significant differences between the mTBI group and controls. In addition to group differences, six studies reported significant variation over time. Brain Network Analysis(BNA), utilized in seven studies, was the primary FC analysis recorded. Two of the five studies that reported significant differences following mTBI utilized the BNA. The other three applied alternative analysis methods.

DISCUSSION

FC assessment based on EEG can identify some differences in children with mTBI. BNA was more useful in following changes over time. Further research is suggested, considering the limited age range and number of retrieved studies.

Neurophysiological Markers to Guide Return to Sport After Sport-Related Concussion

SUMMARY

Sport-related concussion (SRC) has been defined as a subset of mild traumatic brain injury (mTBI), without structural abnormalities, reflecting a functional disturbance. Over the past decade, SRC has gained increasing awareness and attention, which coincides with an increase in incidence rates. Because this injury has been considered one of the most challenging encounters for clinicians, there is a need for objective biomarkers to aid in diagnosis (i.e., presence/severity) and management (i.e., return to sport) of SRC/mTBI.The primary aim of this article was to present state-of-the-art neurophysiologic methods (e.g., electroencephalography, magnetoencephalography, transcranial magnetic stimulation, and autonomic nervous system) that are appropriate to investigate the complex pathophysiological process of a concussion. A secondary aim was to explore the potential for evidence-based markers to be used in clinical practice for SRC management. The article concludes with a discussion of future directions for SRC research with specific focus on clinical neurophysiology.

Role of biomarkers and emerging technologies in defining and assessing neurobiological recovery after sport-related concussion: a systematic review

OBJECTIVE

Determine the role of fluid-based biomarkers, advanced neuroimaging, genetic testing and emerging technologies in defining and assessing neurobiological recovery after sport-related concussion (SRC).

DESIGN

Systematic review.

DATA SOURCES

Searches of seven databases from 1 January 2001 through 24 March 2022 using keywords and index terms relevant to concussion, sports and neurobiological recovery. Separate reviews were conducted for studies involving neuroimaging, fluid biomarkers, genetic testing and emerging technologies. A standardised method and data extraction tool was used to document the study design, population, methodology and results. Reviewers also rated the risk of bias and quality of each study.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they: (1) were published in English; (2) represented original research; (3) involved human research; (4) pertained only to SRC; (5) included data involving neuroimaging (including electrophysiological testing), fluid biomarkers or genetic testing or other advanced technologies used to assess neurobiological recovery after SRC; (6) had a minimum of one data collection point within 6 months post-SRC; and (7) contained a minimum sample size of 10 participants.

RESULTS

A total of 205 studies met inclusion criteria, including 81 neuroimaging, 50 fluid biomarkers, 5 genetic testing, 73 advanced technologies studies (4 studies overlapped two separate domains). Numerous studies have demonstrated the ability of neuroimaging and fluid-based biomarkers to detect the acute effects of concussion and to track neurobiological recovery after injury. Recent studies have also reported on the diagnostic and prognostic performance of emerging technologies in the assessment of SRC. In sum, the available evidence reinforces the theory that physiological recovery may persist beyond clinical recovery after SRC. The potential role of genetic testing remains unclear based on limited research.

CONCLUSIONS

Advanced neuroimaging, fluid-based biomarkers, genetic testing and emerging technologies are valuable research tools for the study of SRC, but there is not sufficient evidence to recommend their use in clinical practice.

PROSPERO REGISTRATION NUMBER

CRD42020164558.

Norm-Based Cutoffs as Predictors of Prolonged Recovery After Adolescent Sport-Related Concussion

OBJECTIVES

To identify predictors of prolonged recovery (ie, >28 days) using patient demographic factors and healthy, norm-based cutoffs on a multimodal test battery in adolescents after sport-related concussions (SRCs).

DESIGN

Retrospective cohort. Patients were deemed recovered after successful completion of return-to-play/school protocols and received medical clearance.

SETTING

Community concussion clinic.

PATIENTS

Male and female adolescent student athletes diagnosed with a SRC and evaluated within 1 week of injury.

INDEPENDENT VARIABLES

Patient demographics, medical history, injury description, computerized neurocognitive testing, vestibular/ocular testing, and symptoms at initial clinical visit.

MAIN OUTCOME MEASURES

Performance on clinical testing to predict recovery duration, classified as normal (<28 days) or prolonged (>28 days).

RESULTS

A total of 201 adolescent student athletes (age = 15.3 ± 1.4 years) were included (female 35%). Average recovery duration for the entire cohort was 22.3 ± 13.3 days, with 22% (n = 45) of adolescent student athletes taking >28 days to recover. The final model was 88.3% accurate in classifying normal and prolonged recovery. Predictor variables included sex, loss of consciousness, history of ocular disorder, history of concussion, performance on visual motor speed composite, visual motion sensitivity symptom provocation and near point of convergence distance, number-naming total time, and symptom count.

CONCLUSIONS

These findings suggest that using norm-based cutoffs from cognitive, oculomotor, and vestibulo-ocular testing and symptom reporting, clinicians can accurately predict a prolonged recovery (sensitivity = 81%) and normal recovery (specificity = 83%) in an adolescent, SRC cohort.

Towards defining biomarkers to evaluate concussions using virtual reality and a moving platform (BioVRSea)

Current diagnosis of concussion relies on self-reported symptoms and medical records rather than objective biomarkers. This work uses a novel measurement setup called BioVRSea to quantify concussion status. The paradigm is based on brain and muscle signals (EEG, EMG), heart rate and center of pressure (CoP) measurements during a postural control task triggered by a moving platform and a virtual reality environment. Measurements were performed on 54 professional athletes who self-reported their history of concussion or non-concussion. Both groups completed a concussion symptom scale (SCAT5) before the measurement. We analyzed biosignals and CoP parameters before and after the platform movements, to compare the net response of individual postural control. The results showed that BioVRSea discriminated between the concussion and non-concussion groups. Particularly, EEG power spectral density in delta and theta bands showed significant changes in the concussion group and right soleus median frequency from the EMG signal differentiated concussed individuals with balance problems from the other groups. Anterior–posterior CoP frequency-based parameters discriminated concussed individuals with balance problems. Finally, we used machine learning to classify concussion and non-concussion, demonstrating that combining SCAT5 and BioVRSea parameters gives an accuracy up to 95.5%. This study is a step towards quantitative assessment of concussion.

Concussion Characteristics and Early Postinjury Outcomes Between College Students and Intercollegiate Athletes

OBJECTIVE

To describe concussion characteristics among general college students and compare postinjury outcomes to intercollegiate student athletes.

DESIGN

Retrospective cohort.

SETTING

Large university in the Southeast region of the United States.

PARTICIPANTS

A total of 179 (N=179) college students' (female=120; 67.0%; 23.9±3.9 years) and 49 athletes' (female=28, 57.1%;19.3±1.3 years) medical records were examined. Participants self-reported injury mechanism, health history information, and completed clinical assessments acutely (<7 days postinjury).

MAIN OUTCOME MEASURES

Descriptive statistics were calculated for each group. Concussion outcomes between students with and without certain health history diagnoses were assessed using separate t tests. We conducted univariate regression analyses to determine if sex, age, and time from concussion to first clinical assessment were significant predictors of clinical outcomes. Statistically significant variables were included as covariates in a series of 1-way analyses of covariance to identify differences in balance, symptom severity, total symptom presence, and neurocognitive domain performance between students and athletes. Fisher exact tests were used to compare health history information between groups (α<0.05).

RESULTS

Among students, 24% reported sustaining a concussion while participating in recreational sports, and 27% of impacts occurred to the back of the head. Students had higher proportions of headache, migraine, anxiety, and depression (P<.05). Students reported greater total symptom presence (P=.006) and performed worse on the computerized neurocognitive test domain score for complex attention (P=.015) relative to athletes.

CONCLUSIONS

These findings highlight the need for better access to medical care for non- National Collegiate Athletic Association sanctioned athletes because of a large proportion of concussions in the student sample being sustained during sports participation. Identifying common injury mechanisms can provide clinicians with powerful information to improve evaluation and treatment models.

The Current Status of Concussion Assessment Scales: A Critical Analysis Review

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Concussion is a complex pathophysiologic process that affects the brain; it is induced by biomechanical forces, with alteration in mental status with or without loss of consciousness.

»

Concussion assessment tools may be broadly categorized into (1) screening tests such as the SAC (Standardized Assessment of Concussion), the BESS (Balance Error Scoring System), and the King-Devick (KD) test; (2) confirmatory tests including the SCAT (Sport Concussion Assessment Tool), the ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing), and the VOMS (Vestibular Oculomotor Screening); and (3) objective examinations such as brain network activation (BNA) analysis, imaging studies, and physiologic markers.

»

The KD, child SCAT3 (cSCAT3), child ImPACT (cImPACT), and VOMS tests may be used to evaluate for concussion in the pediatric athlete.

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Future work with BNA, functional magnetic resonance imaging, diffusion tensor imaging, and serum biomarkers may provide more objective assessment of concussion, neurologic injury, and subsequent recovery.

One size fits none: neurobiologic-specific modifications for the assessment, diagnosis, and treatment of sport-related concussion (SRC)

PRIMARY OBJECTIVE

- To discuss how the underlying neuroanatomy and neurobiology of five sport-related concussion (SRC) clinical profiles impacts assessment and treatment.

RESEARCH DESIGN

- Narrative review.

METHODS AND PROCEDURES

- Based on the current literature and clinical experience, arguments against the traditional SRC protocol and for a clinical profiles-based SRC protocol are made.

MAIN OUTCOMES AND RESULTS

- While the clinical profiles-based SRC protocol is widely used and accepted, there has been little published regarding the link to the underlying neuropathology. Our narrative review describes the five SRC clinical profiles: vestibular, ocular, mood, post-traumatic migraine, and cognitive/fatigue. For these profiles, the underlying neuroanatomy and neurobiology is outlined, as well as how that anatomy and biology impact the profiles' etiology, assessment, and treatment. The cervical and sleep modifiers are also briefly covered.

CONCLUSIONS

- Utilizing this model, clinicians are able to provide an individualized assessment, conceptualization, and treatment plan for SRC, leading to improved outcomes and clinical experiences for athletes.

Subtypes of Sport-Related Concussion: a Systematic Review and Meta-cluster Analysis

Objective

Current clinical guidelines provide a unitary approach to manage sport-related concussion (SRC), while heterogeneity in the presentation of symptoms suggests that subtypes of SRC may exist. We systematically reviewed the available evidence on SRC subtypes and associated clinical outcomes.

Data Sources

Ovid Medline, Embase, PsycINFO, and SPORTDiscus

Eligibility Criteria for Selecting Studies

Electronic databases were searched for studies: (i) identifying SRC symptom clusters using classification methodology; or (ii) associating symptom clusters to clinical outcome variables. A total of 6,146 unique studies were identified, of which 75 full texts were independently assessed by two authors for eligibility. A total of 22 articles were included for systematic review.

Data Extraction

Two independent authors performed data extraction and risk of bias analysis using the Cochrane Collaboration tool.

Data Synthesis

Six studies found evidence for existence of SRC symptom clusters. Combining the available literature through Multiple Correspondence Analysis (MCA) provided evidence for the existence of a migraine cluster, a cognitive–emotional cluster, a sleep–emotional cluster, a neurological cluster, and an undefined feelings cluster. Nineteen studies found meaningful associations between SRC symptom clusters and clinical outcomes. Clusters mapping to the migraine cluster were most frequently reported in the literature and were most strongly related to aspects of clinical outcome.

Conclusions

The available literature provides evidence for the existence of at least five subtypes in SRC symptomatology, with clear relevance to clinical outcome. Systematically embedding the differentiation of SRC subtypes into prognosis, clinical management, and intervention strategies may optimize the recovery from SRC.

Electronic supplementary material

The online version of this article (10.1007/s40279-020-01321-9) contains supplementary material, which is available to authorized users.

Quantitative Multimodal Assessment of Concussion Recovery in Youth Athletes

OBJECTIVE

To evaluate recovery trajectories among youth athletes with a concussion and healthy controls across different domains using a quantitative and multifaceted protocol.

STUDY DESIGN

Prospective repeated measures.

PARTICIPANTS

Youth athletes diagnosed with a concussion between the ages of 8 and 18 years were evaluated (1) within 10 days after injury, (2) approximately 3 weeks after injury, and (3) after return-to-play clearance. Control participants completed the same protocol.

SETTING

Sport concussion clinic.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Participants underwent a multifaceted protocol that assessed symptoms (postconcussion symptom scale [PCSS]), dual-task gait, event-related potentials (ERPs), and eye tracking.

RESULTS

Sixty-seven athletes participated: 36 after concussion (age = 14.0 ± 2.6 years; 44% female) and 31 controls (age = 14.6 ± 2.2 years; 39% female). Concussion symptoms were higher for the concussion group compared with controls at the first (PCSS = 31.7 ± 18.8 vs 1.9 ± 2.9; P < 0.001) and second time points (PCSS = 10.8 ± 11.2 vs 1.8 ± 3.6; P = 0.001) but resolved by the final assessment (PCSS = 1.7 ± 3.6 vs 2.0 ± 3.8; P = 0.46). The concussion group walked slower during dual-task gait than controls at all 3 tests including after return-to-play clearance (0.83 ± 0.19 vs 0.95 ± 0.15 m/s; P = 0.049). There were no between-group differences for ERP connectivity or eye tracking. Those with concussions had a decrease in ERP connectivity recovery over the 3 time points, whereas control participants' scores increased (concussion Δ = -8.7 ± 28.0; control Δ = 13.9 ± 32.2; χ2 = 14.1, P = 0.001).

CONCLUSIONS

Concussion is associated with altered dual-task gait speeds after resolution of concussion symptoms, but ERP and eye tracking measures did not demonstrate between-group differences across time. Some objective approaches to concussion monitoring may support with identifying deficits after concussion, but further work is required to delineate the role of gait, electrophysiological, and eye tracking methods for clinical decision-making.

Brain Network Analysis of EEG Recordings Can Be Used to Assess Cognitive Function in Teenagers With 15q13.3 Microdeletion Syndrome

15q13.3 microdeletion syndrome causes a spectrum of cognitive disorders, including intellectual disability and autism. We assessed the ability of the EEG analysis algorithm Brain Network Analysis (BNA) to measure cognitive function in 15q13.3 deletion patients, and to differentiate between patient and control groups. EEG data was collected from 10 individuals with 15q13.3 microdeletion syndrome (14–18 years of age), as well as 30 age-matched healthy controls, as the subjects responded to Auditory Oddball (AOB) and Go/NoGo cognitive tasks. It was determined that BNA can be used to evaluate cognitive function in 15q13.3 microdeletion patients. This analysis also significantly differentiates between patient and control groups using 5 scores, all of which are produced from ERP peaks related to late cortical components that represent higher cognitive functions of attention allocation and response inhibition (P < 0.05).

Preliminary investigation of a multimodal enhanced brain function index among high school and collegiate concussed male and female athletes

Objective: The primary purpose of this study was to examine the longitudinal effects of sports-related concussion (SRC) on a multi-faceted assessment battery which included neuropsychological testing, symptom reporting, and enhanced brain function index (eBFI) among athletes with and without SRC. A secondary purpose was to explore longitudinal sex differences among these measures in athletes with and without SRC. Methods: A case-control, repeated-measures design was used for this study. A total of 186 athletes (concussed group:n= 87 controls:n= 99) participated in the study. A repeated-measures design was used in which each athlete was tested at four time points following an SRC: within 72 h of injury (Day 0; 2.0 ± 0.9 days following injury), 5 days following injury (Day 5; 5.0 ± 0.0), at return to play (RTP; 18.3 ± 13.8 days following injury), and within 45 days following RTP (RTP45; 66.2 ± 19.0 days following injury). All analyses were conducted separately using a 2 (Group: concussed, control) × 2 (Sex: male, female) × 4 (Time:Day 0, Day 5, RTP, RTP45) univariate multi-level model including the random intercept for each participant. A higher eBFI score indicates a better performance. Alpha level was set aprior at .05. This study was registered on clinicaltrials.gov (Objective Brain Function Assessment of mTBI/Concussion in College/high school Athletes NCT02477943, NCT02661633, CAS 13-25 NCT03963804). Results: Concussed athletes exhibited impaired eBFI within 72 h of SRC and at Day 5 compared to controls (p<.001). Analysis of eBFI scores between male and female athletes revealed a main effect of sex (p=.05), with female athletes exhibiting lower eBFI (33.9 ± 30.7) relative to male athletes (40.4 ± 33.0), however, it did not indicate interactions between sex, group, and time (p's ≥ 0.786). Conclusion: The eBFI appears to be a useful tool in determining concussed athletes during the acute stages of an SRC. However, this index may lack the sensitivity to detect sex-related differences between groups at various time points during recovery.

Increased Risk of Musculoskeletal Injury Following Sport-Related Concussion: A Perception-Action Coupling Approach

Recent studies have concluded that athletes have increased risk of musculoskeletal injury following sport-related concussion. While an underlying explanation is still unknown, perceptual-motor control may be implicated in this increased risk. Some authors have purported that indirect perception (i.e., a "top-down" view of neuromuscular control) may be disrupted following sport-related concussion. Direct perception theory states that the athlete and environment are inextricably linked in a continuous perception-action coupling loop. That is, the athlete is able to directly perceive opportunities for action (e.g., "affordances") in the environment. Based on these notions, the aim of the current paper was to introduce a theoretical model that argues that sport-related concussion may dysregulate the direct perception process, potentially increasing behavioral risk of musculoskeletal injury during sport. Our model is integrated with a sport-related concussion clinical treatment model, which highlights individualized profiles that characterize the heterogeneous response to sport-related concussion. These profiles have a typical constellation of symptoms (e.g., anxiety, fatigue, ocular dysfunction, etc.), which themselves have been associated with disrupted perception-action coupling, independent of sport-related concussion. Therefore, we argue that athletes who have not re-established perception-action coupling loops following sport-related concussion may be at increased risk of subsequent musculoskeletal injury.

The Development of Adolescent Chronic Pain following Traumatic Brain Injury and Surgery: The Role of Diet and Early Life Stress

Pain is evolutionarily necessary for survival in that it reduces tissue damage by signaling the body to respond to a harmful stimulus. However, in many circumstances, acute pain becomes chronic, and this is often dysfunctional. Adolescent chronic pain is a growing epidemic with an unknown etiology and limited effective treatment options. Given that the relationship between acute pain and chronic pain is not straightforward, there is a need to better understand the factors that contribute to the chronification of pain. Since early life factors are critical to a variety of outcomes in the developmental and adolescent periods, they pose promise as potential mechanisms that may underlie the transition from acute to chronic pain. This review examines two early life factors: poor diet and adverse childhood experiences (ACEs); they may increase susceptibility to the development of chronic pain following surgical procedures or traumatic brain injury (TBI). Beyond their high prevalence, surgical procedures and TBI are ideal models to prospectively understand mechanisms underlying the transition from acute to chronic pain. Common themes that emerged from the examination of poor diet and ACEs as mechanisms underlying this transition included: prolonged inflammation and microglia activation leading to sensitization of the pain system, and stress-induced alterations to hypothalamic-pituitary-adrenal axis function, where cortisol is likely playing a role in the development of chronic pain. These areas provide promising targets for interventions, the development of diagnostic biomarkers, and suggest that biological treatment strategies should focus on regulating the neuroinflammatory and stress responses in an effort to modulate and prevent the development of chronic pain.

Family History of Migraine Associated With Posttraumatic Migraine Symptoms Following Sport-Related Concussion

OBJECTIVE

To determine whether family history of migraine increased the likelihood of posttraumatic migraine (PTM) symptom presentation in adolescents following concussion, and examine the influence of family history of migraine and PTM on postinjury outcomes.

SETTING

Outpatient concussion clinic.

PARTICIPANTS

A total of 153 patients with concussion (103 males and 50 females) aged 15.72 ± 1.48 years (range 12-18 years).

DESIGN

Cross-sectional, observational study of patients presenting for initial evaluation 4.72 ± 3.05 days (range 1-14) postinjury.

MAIN MEASURES

Computerized neurocognitive testing, symptom report, and vestibular/oculomotor screening.

RESULTS

Patients with a family history of migraine were 2.6 times (odds ratio = 2.60, confidence interval = 1.35-5.02, P = .003) more likely to present with PTM compared with patients without a family history. Results of multivariate analyses of covariance, controlling for concussion history, revealed significant main effects for PTM on (1) Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT)/Post-Concussion Symptom Scale (PCSS) (F = 15.43, P <.001) and (2) Vestibular/Ocular Motor Screening (VOMS) (F = 8.52, P < .001). There was no main effect for family history of migraine on ImPACT/PCSS (P = .22) and VOMS (P = .83) or interaction between family history of migraine and PTM on ImPACT/PCSS (P = .84) and VOMS (P = .52).

CONCLUSION

Family history of migraine is associated with PTM symptoms following sport-related concussion, suggesting a genetic predisposition for migraine may serve as a catalyst or trigger for onset of PTM. However, only presence of PTM, rather than family history of migraine, was related to worse neurocognitive and vestibular/oculomotor outcomes.

Balance control in youth hockey players with and without a history of concussions during a lower limb reaching task

BACKGROUND

Sport-related concussion (SRC) is a functional injury that affects several clinical domains, including balance and cognition. The purpose of this study was, 1) to determine whether a lower limb visuomotor task could identify balance control differences between youth athletes with and without previous SRC; and 2) if balance is affected by training over time.

METHODS

Youth hockey players (n = 34) who reported previous SRC (CONCUSSED; n = 12; mean age = 14.4 yrs., SD = 1.6, mean time from injury = 1.9 yrs., median = 1.7 yrs. [0.6-4.6]) and no history of SRC (CONTROL; n = 22; mean age = 14.7, SD = 1.5) were tested twice over 70 days. Participants stood in single support on a Nintendo Wii Balance board sampled at 100 Hz and performed Go/No-Go tasks with each foot. Five FitLight Trainer™ (Aurora, ON) lights were arranged on the floor at 60°, 30°, and 0° and illuminated in random GREEN (Go) or RED (No-Go). Balance was assessed using root mean square displacement and velocity of CoP in anterior-posterior and medial-lateral directions.

FINDINGS

CONCUSSED had significantly lower velocity of CoP in the anterior-posterior (F_{(1, 32)} = 13.81, p < .001) and medial-lateral (F_{(1, 32)} = 13.80, p < .001) directions than CONTROL, with no learning effects over time (anterior-posterior: F_{(1, 32)} = 0.30, p = .137: F_{(1, 32)} = 0.91, p = .346; medial-lateral: F_{(1, 32)} = 0.91, p = .346). These findings suggest that CONCUSSED consistently performed the task more conservatively.

INTERPRETATION

A lower limb Go/No-Go task may objectively identify differences between youth athletes with and without previous SRC. These visuomotor and balance control deficits may persist beyond clinical recovery.

[Cognitive and paroxysmal disorders in the long-term period of traumatic brain injury in children and adolescents]

Traumatic brain injury (TBI) clinical course and outcomes in children have peculiarities as the damage impacts brain, which growth and maturation are continuing. Thus, TBI interferes into normal processes of neuroontogenesis leading to negative consequences on the cognitive functions development, school education, social skills acquisition. Cognitive and behavioral disorders in children and adolescents in the long-term period of TBI become more prominent in co-occurrence with paroxysmal disorders, including posttraumatic headaches, posttraumatic epilepsy and subclinical epileptiform activity on the EEG. Therapeutic and rehabilitation procedures in in the long-term period of TBI in children and adolescents should be conducted not only during the first 12 months after injury, when they are expected to be the most efficient, but also later on taking into consideration continuing processes of the CNS morphological and functional maturation along with the high neuroplasticity of the developing brain.

Unifying Pathophysiological Explanations for Sports-Related Concussion and Concussion Protocol Management: Literature Review

Objective

There is a plethora of theories about the pathophysiology behind a sport-related concussion. In this review of the literature, the authors evaluated studies on the pathophysiology of sport-related concussion and professional athlete return-to-play guidelines. The goal of this article is to summarize the most common hypotheses for sport-related concussion, evaluate if there are common underlying mechanisms, and determine if correlations are seen between published mechanisms and the most current return-to-play recommendations.

Methods

Two authors selected papers from the past 5 years for literature review involving discussion of sport-related concussion and pathophysiology, pathology, or physiology of concussion using mutually agreed-upon search criteria. After the articles were filtered based on search criteria, pathophysiological explanations for concussion were organized into tables. Following analysis of pathophysiology, concussion protocols and return-to-play guidelines were obtained via a Google search for the major professional sports leagues and synthesized into a summary table.

Results

Out of 1112 initially identified publications, 53 met our criteria for qualitative analysis. The 53 studies revealed 5 primary neuropathological explanations for sport-related concussion, regardless of the many theories talked about in the different papers. These 5 explanations, in order of predominance in the articles analyzed, were (1) tauopathy, (2) white matter changes, (3) neural connectivity alterations, (4) reduction in cerebral perfusion, and (5) gray matter atrophy. Pathology may be sport specific: white matter changes are seen in 47% of football reports, tauopathy is seen in 50% of hockey reports, and soccer reports 50% tauopathy as well as 50% neural connectivity alterations. Analysis of the return-to-play guidelines across professional sports indicated commonalities in concussion management despite individual policies.

Conclusions

Current evidence on pathophysiology for sport-related concussion does not yet support one unifying mechanism, but published hypotheses may potentially be simplified into 5 primary groups. The unification of the complex, likely multifactorial mechanisms for sport-related concussion to a few common explanations, combined with unique findings within individual sports presented in this report, may help filter and link concussion pathophysiology in sport. By doing so, the authors hope that this review will help guide future concussion research, treatment, and management.

No Seasonal Changes in Cognitive Functioning Among High School Football Athletes: Implementation of a Novel Electrophysiological Measure and Standard Clinical Measures

OBJECTIVE

To evaluate neuroelectric and cognitive function relative to a season of football participation. Cognitive and neuroelectric function declines are hypothesized to be present in football athletes.

DESIGN

Observational.

SETTING

Athletic fields and research laboratory.

PATIENTS (OR PARTICIPANTS)

Seventy-seven high school athletes (15.9 + 0.9 years, 178.6 + 7.2 cm, 74.4 + 14.7 kg, and 0.8 + 0.8 self-reported concussions) participating in football (n = 46) and noncontact sports (n = 31).

INTERVENTIONS (OR ASSESSMENT OF RISK FACTORS)

All athletes completed preseason, midseason, and postseason assessments of cognitive and neuroelectric function, self-reported symptoms, and quality of life. All athletes participated in their respective sports without intervention, while head impact exposure in football athletes was tracked using the Head Impact Telemetry System.

MAIN OUTCOME MEASURES

Cognitive performance was based on Cogstate computerized cognitive assessment tool processing speed, attention, learning, working memory speed, and working memory accuracy scores. ElMindA brain network activation amplitude, synchronization, timing and connectivity brain network activation scores demarcated neuroelectric performance. Quality of life was assessed on the Health Behavior Inventory and Satisfaction with Life Scale and symptoms on the SCAT3 inventory.

RESULTS

Football and control sport athletes did not show declines in cognitive or neuroelectric function, quality-of-life measures, or symptom reports across a season of sport participation.

CONCLUSIONS

These findings refute the notion that routine football participation places athletes at risk for acute cognitive declines. The lack of impairment may be associated with no association with head impacts and cognitive function, increased physical activity offsetting any declines, and/or test sensitivity. How these findings are associated with long-term cognitive function is unknown.

Evidence of brain functional deficits following sport-related mild traumatic brain injury

Sport related mild traumatic brain injury (mTBI), generally known as a concussion, is a worldwide critical public health concern nowadays. Despite growing concern emphasized by scientific research and recent media presentation regarding mTBI and its effect in athletics life, the management, and prevention of mTBI are still not properly done. The evaluation mainly hampered due to the lack of proper knowledge, subjective nature of assessment tools including the fact that the brain functional deficits after mTBI can be mild or hidden. As a result, development of an effective tool for proper management of these mild incidents is a subject of active research. In this paper, to examine the neural substrates following mTBI, an analysis based on electroencephalogram (EEG) from twenty control and twenty concussed athletes is presented. Preliminary results suggest that the concussed athletes have a significant increase in delta, theta and alpha power but a decrease in beta power. We also calculated the power for individual frequencies from 1 Hz to 40 Hz in order to find out the specific frequencies with the highest deficits. The significant deficiencies were found at 1-2 Hz of delta band, 6-7 Hz of theta band, 8-10 Hz of the alpha band, and 16-18 Hz and 24-29 Hz of the beta band. Though there was no significant difference as observed in gamma band, we found the deficit was significant at 34-36 Hz range within the gamma band. The observed deficits at various frequencies demonstrate that even if there is no significant difference in the traditional frequency bands, there may be hidden deficits at some specific frequencies within a frequency band. These preliminary results suggest that the EEG analysis at each unity frequency may be more promising means of identifying the neuronal damage than the traditional frequency band based analysis. Eventually, the proposed analysis can provide an improved approximation to monitor the pathophysiological recovery after a concussion.

Post-Concussive Syndrome: a Focus on Post-Traumatic Headache and Related Cognitive, Psychiatric, and Sleep Issues

PURPOSE OF REVIEW

Post-traumatic headache (PTH) is a secondary headache disorder following traumatic brain injury. We sought to examine the recent literature on PTH and associated cognitive, psychiatric, and sleep conditions to understand the latest findings about the associated conditions and available screening tools, and to understand the available treatment options for PTH.

RECENT FINDINGS

Up to one third of PTH patients may have depression and about one quarter may have insomnia. Anxiety and cognitive issues are also common. While there are few studies examining abortive medications for PTH, recent studies of preventive medications examine the efficacy of topiramate, and topiramate may be better than other oral preventive medications. Other currently investigated treatments include nerve blocks, onabotulinum toxin A, transmagnetic stimulation, and behavioral therapy (biofeedback). Due to an expanded focus on and knowledge of concussion and PTH, comorbid psychiatric, cognitive, and sleep issues have become more widely acknowledged and studied. However, more high-quality studies must be conducted to examine the underlying pathophysiology of PTH and associated symptoms and to determine the most effective abortive and preventive treatment options.

Brain Network Activation Technology Does Not Assist with Concussion Diagnosis and Return to Play in Football Athletes

Background

Concussion diagnosis and management remains a largely subjective process. This investigation sought to evaluate the utility of a novel neuroelectric measure for concussion diagnosis and return to play decision-making.

Hypothesis

Brain Network Activation (BNA) scores obtained within 72-h of injury will be lower than the athlete’s preseason evaluation and that of a matched control athlete; and the BNA will demonstrate ongoing declines at the return to play and post-season time points, while standard measures will have returned to pre-injury and control athlete levels.

Design

Case–control study.

Methods

Football athletes with a diagnosed concussion (n = 8) and matched control football athletes (n = 8) completed a preseason evaluation of cognitive (i.e., Cogstate Computerized Cognitive Assessment Tool) and neuroelectric function (i.e., BNA), clinical reaction time, SCAT3 self-reported symptoms, and quality of life (i.e., Health Behavior Inventory and Satisfaction with Life Scale). Following a diagnosed concussion, injured and control athletes completed post-injury evaluations within 72-h, once asymptomatic, and at the conclusion of the football season.

Results

Case analysis of the neuroelectric assessment failed to provide improved diagnostics beyond traditional clinical measures. Statistical analyses indicated significant BNA improvements in the concussed and control groups from baseline to the asymptomatic timepoint.

Conclusion

With additional attention being placed on rapid and accurate concussion diagnostics and return to play decision-making, the addition of a novel neuroelectric assessment does not appear to provide additional clinical benefit at this time. Clinicians should continue to follow the recommendations for the clinical management of concussion with the assessment of the symptom, cognitive, and motor control domains.

Differences in Callosal and Forniceal Diffusion between Patients with and without Postconcussive Migraine

BACKGROUND AND PURPOSE

Posttraumatic migraines are common after mild traumatic brain injury. The purpose of this study was to determine if a specific axonal injury pattern underlies posttraumatic migraines after mild traumatic brain injury utilizing Tract-Based Spatial Statistics analysis of diffusion tensor imaging.

MATERIALS AND METHODS

DTI was performed in 58 patients with mild traumatic brain injury with posttraumatic migraines. Controls consisted of 17 patients with mild traumatic brain injury without posttraumatic migraines. Fractional anisotropy and diffusivity maps were generated to measure white matter integrity and were evaluated by using Tract-Based Spatial Statistics regression analysis with a general linear model. DTI findings were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient.

RESULTS

Patients with mild traumatic brain injury with posttraumatic migraines were not significantly different from controls in terms of age, sex, type of injury, or neurocognitive test performance. Patients with posttraumatic migraines had higher initial symptom severity (P = .01) than controls. Compared with controls, patients with mild traumatic brain injury with posttraumatic migraines had decreased fractional anisotropy in the corpus callosum (P = .03) and fornix/septohippocampal circuit (P = .045). Injury to the fornix/septohippocampal circuit correlated with decreased visual memory (r = 0.325, P = .01). Injury to corpus callosum trended toward inverse correlation with recovery (r = -0.260, P = .05).

CONCLUSIONS

Injuries to the corpus callosum and fornix/septohippocampal circuit were seen in patients with mild traumatic brain injury with posttraumatic migraines, with injuries in the fornix/septohippocampal circuit correlating with decreased performance on neurocognitive testing.

Preliminary investigation of Brain Network Activation (BNA) and its clinical utility in sport-related concussion

Background: The clinical diagnosis and management of patients with sport-related concussion is largely dependent on subjectively reported symptoms, clinical examinations, cognitive, balance, vestibular and oculomotor testing. Consequently, there is an unmet need for objective assessment tools that can identify the injury from a physiological perspective and add an important layer of information to the clinician’s decision-making process.

Objective: The goal of the study was to evaluate the clinical utility of the EEG-based tool named Brain Network Activation (BNA) as a longitudinal assessment method of brain function in the management of young athletes with concussion.

Methods: Athletes with concussion (n = 86) and age-matched controls (n = 81) were evaluated at four time points with symptom questionnaires and BNA. BNA scores were calculated by comparing functional networks to a previously defined normative reference brain network model to the same cognitive task.

Results: Subjects above 16 years of age exhibited a significant decrease in BNA scores immediately following injury, as well as notable changes in functional network activity, relative to the controls. Three representative case studies of the tested population are discussed in detail, to demonstrate the clinical utility of BNA.

Conclusion: The data support the utility of BNA to augment clinical examinations, symptoms and additional tests by providing an effective method for evaluating objective electrophysiological changes associated with sport-related concussions.

Brain Network Activation Analysis Utilizing Spatiotemporal Features for Event Related Potentials Classification

The purpose of this study was to introduce an improved tool for automated classification of event-related potentials (ERPs) using spatiotemporally parcellated events incorporated into a functional brain network activation (BNA) analysis. The auditory oddball ERP paradigm was selected to demonstrate and evaluate the improved tool. Methods: The ERPs of each subject were decomposed into major dynamic spatiotemporal events. Then, a set of spatiotemporal events representing the group was generated by aligning and clustering the spatiotemporal events of all individual subjects. The temporal relationship between the common group events generated a network, which is the spatiotemporal reference BNA model. Scores were derived by comparing each subject's spatiotemporal events to the reference BNA model and were then entered into a support vector machine classifier to classify subjects into relevant subgroups. The reliability of the BNA scores (test-retest repeatability using intraclass correlation) and their utility as a classification tool were examined in the context of Target-Novel classification. Results: BNA intraclass correlation values of repeatability ranged between 0.51 and 0.82 for the known ERP components N100, P200, and P300. Classification accuracy was high when the trained data were validated on the same subjects for different visits (AUCs 0.93 and 0.95). The classification accuracy remained high for a test group recorded at a different clinical center with a different recording system (AUCs 0.81, 0.85 for 2 visits). Conclusion: The improved spatiotemporal BNA analysis demonstrates high classification accuracy. The BNA analysis method holds promise as a tool for diagnosis, follow-up and drug development associated with different neurological conditions.

Investigating a Novel Measure of Brain Networking Following Sports Concussion

Clinicians managing sports-related concussions are left to their clinical judgment in making diagnoses and return-to-play decisions. This study was designed to evaluate the utility of a novel measure of functional brain networking for concussion management. 24 athletes with acutely diagnosed concussion and 21 control participants were evaluated in a research laboratory. At each of the 4 post-injury time points, participants completed the Axon assessment of neurocognitive function, a self-report symptom inventory, and the auditory oddball and go/no-go tasks while electroencephalogram (EEG) readings were recorded. Brain Network Activation (BNA) scores were calculated from EEG data related to the auditory oddball and go/no-go tasks. BNA scores were unable to differentiate between the concussed and control groups or by self-report symptom severity. These findings conflict with previous work implementing electrophysiological assessments in concussed athletes, suggesting that BNA requires additional investigation and refinement before clinical implementation.

The Effects of External Jugular Compression Applied during Head Impact Exposure on Longitudinal Changes in Brain Neuroanatomical and Neurophysiological Biomarkers: A Preliminary Investigation

OBJECTIVES

Utilize a prospective in vivo clinical trial to evaluate the potential for mild neck compression applied during head impact exposure to reduce anatomical and physiological biomarkers of brain injury.

METHODS

This project utilized a prospective randomized controlled trial to evaluate effects of mild jugular vein (neck) compression (collar) relative to controls (no collar) during a competitive hockey season (males; 16.3 ± 1.2 years). The collar was designed to mildly compress the jugular vein bilaterally with the goal to increase intracranial blood volume to reduce risk of brain slosh injury during head impact exposure. Helmet sensors were used to collect daily impact data in excess of 20 g (games and practices) and the primary outcome measures, which included changes in white matter (WM) microstructure, were assessed by diffusion tensor imaging (DTI). Specifically, four DTI measures: fractional anisotropy, mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD) were used in the study. These metrics were analyzed using the tract-based Spatial Statistics (TBSS) approach - a voxel-based analysis. In addition, electroencephalography-derived event-related potentials were used to assess changes in brain network activation (BNA) between study groups.

RESULTS

For athletes not wearing the collar, DTI measures corresponding to a disruption of WM microstructure, including MD and RD, increased significantly from pre-season to mid-season (p < 0.05). Athletes wearing the collar did not show a significant change in either MD or RD despite similar accumulated linear accelerations from head impacts (p > 0.05). In addition to these anatomical findings, electrophysiological network analysis of the degree of congruence in the network electrophysiological activation pattern demonstrated concomitant changes in brain network dynamics in the non-collar group only (p < 0.05). Similar to the DTI findings, the increased change in BNA score in the non-collar relative to the collar group was statistically significant (p < 0.01). Changes in DTI outcomes were also directly correlated with altered brain network dynamics (r = 0.76; p < 0.05) as measured by BNA.

CONCLUSION

Group differences in the longitudinal changes in both neuroanatomical and electrophysiological measures, as well as the correlation between the measures, provide initial evidence indicating that mild jugular vein compression may have reduced alterations in the WM response to head impacts during a competitive hockey season. The data indicate sport-related alterations in WM microstructure were ameliorated by application of jugular compression during head impact exposure. These results may lead to a novel line of research inquiry to evaluate the effects of protecting the brain from sports-related head impacts via optimized intracranial fluid dynamics.

Stability of an ERP-based measure of brain network activation (BNA) in athletes: A new electrophysiological assessment tool for concussion

PRIMARY OBJECTIVE

To determine test-re-test reliabilities of novel Evoked Response Potential (ERP)-based Brain Network Activation (BNA) scores in healthy athletes.

RESEARCH DESIGN

Observational, repeated-measures study.

METHODS AND DESIGN

Forty-two healthy male and female high school and collegiate athletes completed auditory oddball and go/no-go ERP assessments at baseline, 1 week, 6 weeks and 1 year. The BNA algorithm was applied to the ERP data, considering electrode location, frequency band, peak latency and normalized amplitude to generate seven unique BNA scores for each testing session.

MAIN OUTCOMES AND RESULTS

Mean BNA scores, intra-class correlation coefficient (ICC) values and reliable change (RC) values were calculated for each of the seven BNA networks. BNA scores ranged from 46.3 ± 34.9 to 69.9 ± 22.8, ICC values ranged from 0.46-0.65 and 95% RC values ranged from 38.3-68.1 across the seven networks.

CONCLUSIONS

The wide range of BNA scores observed in this population of healthy athletes suggests that a single BNA score or set of BNA scores from a single after-injury test session may be difficult to interpret in isolation without knowledge of the athlete's own baseline BNA score(s) and/or the results of serial tests performed at additional time points. The stability of each BNA network should be considered when interpreting test-re-test BNA score changes.