Predictors of clinical recovery from concussion: a systematic review

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.

More Physical Activity after Concussion Is Associated with Faster Return to Play among Adolescents

Concussion management has evolved to de-emphasize rest in favor of early introduction of post-injury physical activity. However, the optimal quantity, frequency and intensity of physical activity are unclear. Our objective was to examine the association between objective physical activity metrics and clinical recovery after concussion. We prospectively enrolled a cohort of 32 youth athletes with concussion, evaluated within 14 days of injury and after return-to-play (RTP) clearance. For two weeks after enrollment, we quantified steps/day and exercise frequency, duration, and intensity via wrist-worn actigraphy. We grouped participants by RTP clearance timing (<28 days vs. ≥28 days). Seventeen (53%) participants required ≥28 days post-concussion for RTP clearance. Groups were similar in age (14.9 ± 1.9 vs. 15.4 ± 1.5 years; p = 0.38), proportion of females (47% vs. 40%; p = 0.69), and concussion history (59% vs. 47%; p = 0.49). During the study period, the RTP ≥ 28 days group took fewer steps/day (8158 ± 651 vs. 11,147 ± 4013; p = 0.02), exercised fewer days/week (2.9 ± 2.4 vs. 5.0 ± 1.9 days/week; p = 0.01), and exercised fewer total minutes/week (117 ± 122 vs. 261 ± 219 min/week; p = 0.03). Furthermore, we observed ≥10,251 average steps/day, ≥4 exercise sessions/week, and exercising ≥134 total minutes/week were optimal cutpoints to distinguish between groups. These findings support the benefit of physical activity during concussion recovery.

Influence of concomitant injuries on post-concussion symptoms after a mild traumatic brain injury - a prospective multicentre cohort study

Objectives: To compare post-concussion symptoms (PCS) and return to normal activities between mild Traumatic Brain Injury (mTBI) patients with or without concomitant injuries at 7-and 90 days post-mTBI.Methods: Design: Sub-analysis of a multicentre prospective cohort study.

PARTICIPANTS AND SETTING

patients with mTBI from 7 Canadian Emergency Departments.

PROCEDURE

Research assistants conducted telephone follow-ups using the Rivermead Postconcussion Symptoms Questionnaire (RPQ) at 7-, 30- and 90 days post-mTBI.

MAIN OUTCOME

Presence of PCS (RPQ: ≥3 symptoms) at 90 days.

SECONDARY OUTCOMES

RPQ score ≥21, prevalence of individual RPQ symptoms and patients' return to normal activities, at 7- and 90-days. Adjusted risk ratios (RR) were calculated.Results: 1725 mTBI patients were included and 1055 (61.1%) had concomitant injuries. Patients with concomitant injuries were at higher risk of having ≥3 symptoms on the RPQ (RR:1.26 [95% CI 1.01-1.58]) at 90 days. They were also at higher risk of experiencing specific symptoms (dizziness, fatigue, headaches and taking longer to think) and of non-return to their normal activities (RR:2.11 [95% CI 1.30-3.45]).Conclusion: Patients with concomitant injuries have slightly more PCS and seemed to be at higher risk of non-return to their normal activities 90 days, compared to patients without concomitant injuries.

Prediction of risk of prolonged post-concussion symptoms: Derivation and validation of the TRICORDRR (Toronto Rehabilitation Institute Concussion Outcome Determination and Rehab Recommendations) score

BACKGROUND

Approximately 10% to 20% of people with concussion experience prolonged post-concussion symptoms (PPCS). There is limited information identifying risk factors for PPCS in adult populations. This study aimed to derive a risk score for PPCS by determining which demographic factors, premorbid health conditions, and healthcare utilization patterns are associated with need for prolonged concussion care among a large cohort of adults with concussion.

METHODS AND FINDINGS

Data from a cohort study (Ontario Concussion Cohort study, 2008 to 2016; n = 1,330,336) including all adults with a concussion diagnosis by either primary care physician (ICD-9 code 850) or in emergency department (ICD-10 code S06) and 2 years of healthcare tracking postinjury (2008 to 2014, n = 587,057) were used in a retrospective analysis. Approximately 42.4% of the cohort was female, and adults between 18 and 30 years was the largest age group (31.0%). PPCS was defined as 2 or more specialist visits for concussion-related symptoms more than 6 months after injury index date. Approximately 13% (73,122) of the cohort had PPCS. Total cohort was divided into Derivation (2009 to 2013, n = 417,335) and Validation cohorts (2009 and 2014, n = 169,722) based upon injury index year. Variables selected a priori such as psychiatric disorders, migraines, sleep disorders, demographic factors, and pre-injury healthcare patterns were entered into multivariable logistic regression and CART modeling in the Derivation Cohort to calculate PPCS estimates and forward selection logistic regression model in the Validation Cohort. Variables with the highest probability of PPCS derived in the Derivation Cohort were: Age >61 years ([Formula: see text] = 0.54), bipolar disorder ([Formula: see text] = 0.52), high pre-injury primary care visits per year ([Formula: see text] = 0.46), personality disorders ([Formula: see text] = 0.45), and anxiety and depression ([Formula: see text] = 0.33). The area under the curve (AUC) was 0.79 for the derivation model, 0.79 for bootstrap internal validation of the Derivation Cohort, and 0.64 for the Validation model. A limitation of this study was ability to track healthcare usage only to healthcare providers that submit to Ontario Health Insurance Plan (OHIP); thus, some patients seeking treatment for prolonged symptoms may not be captured in this analysis.

CONCLUSIONS

In this study, we observed that premorbid psychiatric conditions, pre-injury health system usage, and older age were associated with increased risk of a prolonged recovery from concussion. This risk score allows clinicians to calculate an individual's risk of requiring treatment more than 6 months post-concussion.

Condition-specific health-related quality of life amongst amateur athletes six months and one-year following sport-related concussion: A prospective, follow-up

OBJECTIVE

To prospectively investigate the condition-specific health-related quality of life (HRQoL) of athletes six months and one-year following sport-related concussion.

DESIGN

Prospective, longitudinal study.

SETTING

Clinical research centre at university school of public health.

PARTICIPANTS

Amateur athletes who were diagnosed with sport-related concussion within one-week after presenting to a hospital emergency department were recruited along with sex-, age-, and activity-matched, non-concussed, control athletes. Concussion and control participants were assessed six months and one-year following sport-related concussion and study enrolment, respectively.

MAIN OUTCOME MEASURES

Participants completed the Post-Concussion Symptom Scale and five condition-specific HRQoL patient-reported outcome measures - Headache Impact Test-6, Fatigue Severity Scale, Neck Disability Index, Generalised Anxiety Disorder-7, and Dizziness Handicap Inventory. We performed Frequentist and Bayesian mixed-design analyses of variance to compare the concussion group and control group at both assessments and quantify whether there was greater evidence in favour of the null hypothesis compared with the alternative hypothesis.

RESULTS

At six-month and one-year assessments, the concussion group (n = 47; male = 72%; mean (SD) age = 22.68 (5.07)) and the control group (n = 47; male = 72%; mean (SD) age = 23.81 (4.60)) reported similar clinical symptom severity scores and condition-specific HRQoL. The proportion of athletes in the concussion group with clinically-impaired scores was similar to the proportion of non-concussed athletes with clinically-impaired scores. At six-month and one-year assessments, there was moderate-to-very strong evidence that there was no difference between concussion and control participants' perceptions of the effects of headache, fatigue, neck pain, anxiety, and dizziness on HRQoL.

CONCLUSION

There was moderate-to-very strong evidence in favour of no difference between the concussion and control groups on symptom severity scores and condition-specific HRQoL patient-reported outcome measures at six-month and one-year assessments. These results suggest that condition-specific HRQoL returns to the levels of non-concussed individuals within six months following sport-related concussion.

Early injury evaluation following concussion is associated with improved recovery time in children and adolescents

OBJECTIVES

Delayed treatment for paediatric concussion may impact recovery trajectory. This study aims to determine the relationship between time to evaluation and concussion recovery in children and adolescents.

DESIGN

Retrospective cross-sectional study.

METHODS

Records from 341 children and adolescents, aged 7-18 years, from a tertiary referral concussion clinic were analysed. All participants were assessed using a standardised concussion test battery by a specialist concussion physician and graded exercise testing. Evaluation time was defined as the number of days from injury occurrence to first presentation at the concussion clinic. Three distinct time to evaluation periods were categorised as: early evaluation (<14 days), mid evaluation (14-28 days), and late evaluation (>28 days). The main outcome measure was recovery time (days).

RESULTS

A total of 341 participants (mean age 13.0 ± 2.3, 74% male) were included in the study. Of these, 89 received evaluation during the early phase (mean age 12.2 ± 2.5, 65% male), 124 during the mid phase (mean age 13.1 ± 2.2, 81% male) and 128 during the late phase (mean age 13.5 ± 2.1, 75% male) following injury. Participants receiving late evaluation took three times longer to recover (mean 148.0 days, 95% CI: 121.1-173.9) compared to early (mean 38.7 days, 95% CI: 30.7-46.7) and mid (mean 51.5 days, 95% CI: 39.7-63.4) evaluation. There was a strong positive correlation between recovery time and evaluation time (r = 0.66, p < 0.001).

CONCLUSIONS

Delaying time to evaluation following a concussion can significantly prolong recovery from injury in children and adolescents.

Anxiety-related concussion perceptions of collegiate athletes

OBJECTIVES

The purpose of this study was to identify collegiate athletes' anxiety-related concussion perceptions and examine factors that may be related to increased anxiety injury beliefs.

DESIGN

Cross-sectional study.

METHODS

Male and female Division I, II and III NCAA collegiate athletes (n = 482) completed a 10- to 15-minute survey examining their demographics, diagnosed concussion history, concussion knowledge, and public media sources they have previously acquired concussion information from. The survey also included the Perceptions of Concussion Inventory for Athletes (PCI-A) which results in six outcome variables (anxiety, effects, control, clarity, treatment, and symptom variability). Univariable and a backward stepwise multivariable logistic regression model were utilized to identify variables that were associated with greater (above median) negative anxiety-related concussion perception scores.

RESULTS

Collegiate athletes displayed moderate anxiety-related concussion perceptions (12.8 ± 3.2; scores ranged from 4 - low anxiety to 20 - high anxiety). The majority of participants reported that concussions are upsetting to them (60.7%), with a sizable proportion being worried (46.7%), fearful (40.7%), or anxious (25.0%) about sustaining a concussion. In the multivariable regression, higher perception that concussions have long-term effects (OR = 2.72; 95% CI: 1.79-4.12), greater beliefs of internal control to influence concussion outcomes (OR = 1.78; 95% CI: 1.15-2.75), and female sex (OR = 1.77; 95% CI: 1.15-2.71) were associated with higher anxiety beliefs.

CONCLUSIONS

This study for the first time establishes that negative, anxiety-related perceptions about concussions are prevalent in a collegiate athlete population. Addressing these perceptions through evidence-based, educational and management initiatives, such as highlighting that concussions are treatable and most do not result in long-term negative consequences with early diagnosis and proper management, are critical to improve emotions surrounding concussion. This may be particularly important for female athletes in this population.

Post-traumatic headache attributed to traumatic brain injury: classification, clinical characteristics, and treatment

Post-traumatic headache is a common sequela of traumatic brain injury and is classified as a secondary headache disorder. In the past 10 years, considerable progress has been made to better understand the clinical features of this disorder, generating momentum to identify effective therapies. Post-traumatic headache is increasingly being recognised as a heterogeneous headache disorder, with patients often classified into subphenotypes that might be more responsive to specific therapies. Such considerations are not accounted for in three iterations of diagnostic criteria published by the International Headache Society. The scarcity of evidence-based approaches has left clinicians to choose therapies on the basis of the primary headache phenotype (eg, migraine and tension-type headache) and that are most compatible with the clinical picture. A concerted effort is needed to address these shortcomings and should include large prospective cohort studies as well as randomised controlled trials. This approach, in turn, will result in better disease characterisation and availability of evidence-based treatment options.

Risk factors associated with concussions in a college student population

PURPOSE

To determine risk factors associated with concussion among the general collegiate population using a unique data linkage methodology.

METHODS

Student health medical, counseling, and disability access service data were linked with university enrollment data to provide a comprehensive, deidentified dataset of students who sought care at the student health center for concussion from 2016-2020. Using chi-squared tests and logistic regression, characteristics of students with and without concussion were evaluated.

RESULTS

During the study period, 506 concussions from 474 students were identified (cumulative incidence rate of 51.7 per 10,000 students). Significant predictors of concussion included: younger age (<21 years): odds ratio (OR) = 3.52 (95% confidence intervals [CI], 2.78, 4.50), Greek affiliation: OR = 1.89 (95% CI, 1.56, 2.30), and utilization of counseling and psychological services: OR = 1.92 (95% CI 1.59, 2.32). Of the students with concussion, 47% had at least one other concussion within the preceding year. History of prior hospitalization or medical imaging for head injury increased subsequent concussion risk by 4.5 fold.

CONCLUSIONS

Linking unique datasets provides a richer understanding of the characteristics and risk factors associated with student concussions than analysis of a single data source. This comprehensive dataset will enable future targeted interventions to prevent and treat college student concussions.

White Matter Abnormalities Associated With Prolonged Recovery in Adolescents Following Concussion

Background: Concussion symptoms in adolescents typically resolve within 4 weeks. However, 20 - 30% of adolescents experience a prolonged recovery. Abnormalities in tracts implicated in visuospatial attention and emotional regulation (i.e., inferior longitudinal fasciculus, ILF; inferior fronto-occipital fasciculus, IFOF; uncinate fasciculus; UF) have been consistently reported in concussion; yet, to date, there are no objective markers of prolonged recovery in adolescents. Here, we evaluated the utility of diffusion MRI in outcome prediction. Forty-two adolescents (12.1 - 17.9 years; female: 44.0%) underwent a diffusion Magnetic Resonance Imaging (dMRI) protocol within the first 10 days of concussion. Based on days of injury until medical clearance, adolescents were then categorized into SHORT (<28 days; N = 21) or LONG (>28 days; N = 21) recovery time. Fractional anisotropy (FA) in the ILF, IFOF, UF, and/or concussion symptoms were used as predictors of recovery time (SHORT, LONG). Forty-two age- and sex-matched healthy controls served as reference. Higher FA in the ILF (left: adjusted odds ratio; AOR = 0.36, 95% CI = 0.15 - 0.91, P = 0.030; right: AOR = 0.28, 95% CI = 0.10 - 0.83, P = 0.021), IFOF (left: AOR = 0.21, 95% CI = 0.07 - 0.66, P = 0.008; right: AOR = 0.30, 95% CI = 0.11 - 0.83, P = 0.020), and UF (left: AOR = 0.26, 95% CI = 0.09 - 0.74, P = 0.011; right: AOR = 0.28, 95% CI = 0.10 - 0.73, P = 0.010) was associated with SHORT recovery. In additional analyses, while adolescents with SHORT recovery did not differ from HC, those with LONG recovery showed lower FA in the ILF and IFOF (P < 0.014). Notably, inclusion of dMRI findings increased the sensitivity and specificity (AUC = 0.93) of a prediction model including clinical variables only (AUC = 0.75). Our findings indicate that higher FA in long associative tracts (especially ILF) might inform a more objective and accurate prognosis for recovery time in adolescents following concussion.

Brain smart – Let's play safely: Evaluation of a concussion education program in schools

Objectives

There are two objectives for this paper. First, to determine effects of a concussion education program in a local school board in terms of concussion-specific knowledge in children and confidence in identifying and managing concussion in adults. Second, to identify differences and similarities in concussion knowledge between children who participate in sports and those who do not and between children with a history of one or more concussions and those without.

Design

A cross sectional survey regarding concussion knowledge was distributed randomly to students and adults at both pre- and posteducation timepoints. A concussion education program was disseminated across the school board for students between the distribution survey timepoints. Following the education program, adults and students completed their respective post-test surveys. Chi-squared tests in SPSS determined the significance of between-group differences.

Results

All 17 adults (100.0%) who had received concussion education recently reported confidence in their knowledge of concussion management, compared to 35.7% adults who had not received education for over a year (p = 0.020). For students, all of whom completed the concussion education training between the pre- and post-tests, there were no significant differences in concussion knowledge scores between athletes and non-athletes (either in or outside of school) or between those with a history of concussion and those without. There were no significant changes in concussion knowledge between the pre- and post-tests, except for one question.

Conclusion

Concussion education programs increase confidence of concussion management protocols in adults involved in sport, but they require improvements to better support knowledge amelioration, particularly for target groups that are at high risk of sustaining another injury.

Presenting features of female collegiate sports-related concussion in South Africa: a descriptive analysis

Background

Sports-related concussion (SRC) is an injury with important implications, especially in collision and contact sports, and has a high symptom burden. Student athletes face particular psychosocial challenges, especially female students with pre-existing anxiety/depression are at increased risk for SRC, and have a higher symptom burden before and after injury.

Objectives

Describing female SRC presenting features at a collegiate campus-based sports medicine service; examining the association of prior concussion history (PCONC) and pre-existing anxiety/depression (PMHDx) with SRC.

Methods

A retrospective cohort and statistical analysis (including corrected effect sizes) of Sport Concussion Assessment Tool (versions 3/5) data (Step 1: PCONC and PMHDx history; Step 2: symptom evaluation) of collegiate female athletes with SRC between 2012 and 2018.

Results

Forty females with SRC were identified (age 23 ± 3). The five most frequent symptoms were headache (n = 34; 85%), feeling slowed down (n = 33; 83%), pressure in head (n = 33; 83%), don't feel right (n = 32; 80%) and fatigue/low-energy (n = 32; 80%). These five symptoms also had the highest self-rated severity (median (IQR): headache (3 (2-4)), feeling slowed down (3 (1-4)), fatigue/low-energy (3 (1-5)), don't feel right (3 (1-4)) and pressure in head (3 (2-4)). PMHDx (n = 8; 62.9 vs 38.6; p = 0.0192; Hedges' g_s = 0.95; large ES), and not PCONC (n = 13; 51.0 vs 39.8; p = 0.2183; Hedges' g_s = 0.48; small ES) was associated with increased mean total symptom severity.

Conclusion

Headache, feeling slowed down, pressure in head, don't feel right and fatigue/low-energy had the highest symptom burden. Total symptom severity was no different in those with and without PCONC, but significantly higher in those with PMHDx.

A Population-Based Study of Pre-Existing Health Conditions in Traumatic Brain Injury

Health factors impacting both the occurrence of, and recovery from traumatic brain injury (TBI) vary in complexity, and present genuine challenges to researchers and healthcare professionals seeking to characterize injury consequences and determine prognosis. However, attempts to clarify causal links between injury characteristics and clinical outcomes (including mortality) often compel researchers to exclude pre-existing health conditions (PECs) in their samples, including psychiatric history, medication usage, and other comorbid conditions. In this pre-registered population-based study (total starting n = 939,123 patients), we examined trends in PEC incidence over 22 years in the state of Pennsylvania (1997-2019) in individuals sustaining TBI (n = 169,452) and individuals with orthopedic injury (n = 87,637). The goal was to determine how PECs interact with age and injury severity to influence short-term outcomes. A further goal was to determine whether number of PECs, or specific PEC clusters contributed to worse outcomes within the TBI cohort, compared with orthopedic injury alone. Primary findings indicate that PECs significantly influenced mortality within the TBI cohort; patients having four or more PECs were associated with approximately a two times greater likelihood of dying in acute care (odds ratio [OR] 1.9). Additionally, cluster analyses revealed four distinct PEC clusters that are age and TBI severity dependent. Overall, the likelihood of zero PECs hovers at ∼25%, which is critical to consider in TBI outcomes work and could potentially contribute to the challenges facing intervention science with regard to reproducibility of findings.

Post-traumatic Headache in Children and Adolescents

PURPOSE OF REVIEW

Post-traumatic headache is a common disorder in the pediatric age group, seen both by child neurologists and by non-neurologists. The current review of post-traumatic headache in children and adolescents aims to review the pathophysiology, risk factors, clinical features, neuroimaging, and both acute and preventive treatment options.

RECENT FINDINGS

Recent literature provides insight into specific risk factors in the pediatric age group for developing post-traumatic headache as well as unique pathophysiologic changes seen in neuroimaging and neurometabolic pathways. It also elucidates common treatment options and novel treatments being currently explored, such as with monoclonal antibodies to CGRP. Finally, current evidence and guidelines recommend the benefit of a gradual return to normal activity based on symptom stability rather than a specific time period. Review of literature on pediatric post-traumatic headache reveals a growing understanding of the factors involved in developing headache after head trauma and the diagnosis/treatment of headache though future research will help further elucidate these areas.

Does time since injury and duration matter in the benefits of physical therapy treatment for concussion?

Objective

To determine if there are differences in post-concussion symptom levels depending on 1) when physical therapy treatment is begun after the concussion and 2) the length of treatment.

Method

Retrospective chart review yielded 202 patients who sustained concussions and were referred for physical therapy. Participants/patients were assigned to independent groups based on time elapsed between concussion and physical therapy (0–14, 15–30, 31–60, 61–120, 121–365 days), and on months spent in treatment (1–4). Pre- and post- treatment scores were documented for the following measures: Sport Concussion Assessment Tool (SCAT), Convergence Insufficiency Symptom Survey (CISS), Dizziness Handicap Inventory (DHI), and Modified Clinical Test of Sensory Interaction on Balance (mCTSIB) using ANOVAs, with a Bonferroni-corrected p-value of p < .005.

Results

All patients demonstrated improvements with treatment, with no significant differences in outcomes for time elapsed since injury (SCAT Symptom Score ( p = .80), SCAT Symptom Severity Score ( p = .97), CISS ( p = .61), DHI ( p = .65), mCTSIB ( p = .13)); or for months in treatment (SCAT Symptom Score ( p = .23), SCAT Symptom Severity Score ( p = .04), CISS ( p = .41), DHI ( p = .37), mCTSIB ( p = .50)).

Conclusions

Improvements were similar for all patients receiving post-concussive physical therapy, regardless of time between injury and treatment onset, and regardless of time spent in treatment. These results may have implications for clinical decision-making and for third party payors’ coverage of post-concussion treatment. Longer periods of treatment may not necessarily be of greater benefit and application of treatment if delayed may also be beneficial. Limitations to the study, such as its retrospective nature, lack of randomization, and convenience sample size are discussed.

Sex-Related Differences in the Incidence, Severity, and Recovery of Concussion in Adolescent Student-Athletes Between 2009 and 2019

BACKGROUND

The sex of an athlete is thought to modulate concussion incidence; however, the effects of sex on concussion severity and recovery are less clear.

PURPOSE

To evaluate sex differences in concussion severity and recovery using a large, heterogeneous sample of young student-athletes with the goal of understanding how sex affects concussion outcomes in young athletes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The Immediate Post-Concussion Assessment and Cognitive Testing results of 11,563 baseline and 5216 postinjury tests were used to calculate the incidence of concussion of adolescent male and female student-athletes ages 12 to 22 years (median, 15 years). The postinjury tests of 3465 male and 1751 female student-athletes evaluated for concussion or head trauma were used to assess differences in the Severity Index (SI) and recovery. Chi-square tests and t tests were used to compare differences in demographic characteristics, incidence, and SI between the 2 cohorts. Multivariable linear, logistic, and Cox proportional hazards regressions were used to control for differences between cohorts in analyses of incidence, SI, and recovery.

RESULTS

When we controlled for demographic differences, female participants had higher odds of concussion (odds ratio, 1.62; 95% CI, 1.40-1.86; P < .0001) and higher SI after concussion (β = 0.67; 95% CI, 0.02-1.32; P = .04). This discrepancy in SI was a result of differences in Symptom (2.40 vs 2.94; P < .0001) and Processing Speed (0.91 vs 1.06; P = .01) composite scores between male and female participants, respectively. We found no effect of sex on time to recovery when controlling for initial concussion SI (hazard ratio, 0.94; 95% CI, 0.78-1.12; P = .48).

CONCLUSION

Using large, multisport cohorts, this study provides evidence that female athletes are at higher risk for more concussions and these concussions are more severe, but male and female athletes have similar recovery times when the analysis controls for initial concussion SI.

Influence of Aerobic Exercise Volume on Postconcussion Symptoms

BACKGROUND

Aerobic exercise has emerged as a useful treatment to improve outcomes among individuals who experience a concussion. However, compliance with exercise recommendations and the effect of exercise volume on symptom recovery require further investigation.

PURPOSE

To examine (1) if an 8-week aerobic exercise prescription, provided within 2 weeks of concussion, affects symptom severity or exercise volume; (2) whether prescription adherence, rather than randomized group assignment, reflects the actual effect of aerobic exercise in postconcussion recovery; and (3) the optimal volume of exercise associated with symptom resolution after 1 month of study.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Individuals randomized to an exercise intervention (n = 17; mean age, 17.2 ± 2.0 years; 41% female; initially tested a mean of 11.3 ± 2.8 days after injury) or standard of care (n = 20; mean age, 16.8 ± 2.2 years; 50% female; initially tested a mean of 10.7 ± 3.2 days after injury) completed an aerobic exercise test within 14 days of injury. They returned for assessments 1 month and 2 months after the initial visit. The aerobic exercise group was instructed to exercise 5 d/wk, 20 min/d (100 min/wk), at a target heart rate based on an exercise test at the initial visit. Participants reported their exercise volume each week over the 8-week study period and reported symptoms at each study visit (initial, 1 month, 2 months). Because of low compliance in both groups, there was no difference in the volume of exercise between the 2 groups.

RESULTS

There were no significant symptom severity differences between the intervention and standard-of-care groups at the initial (median Post-Concussion Symptom Inventory, 15 [interquartile range = 10, 42] vs 20 [11, 35.5]; P = .26), 1-month (4 [0, 28] vs 5.5 [0.5, 21.5]; P = .96), or 2-month (6.5 [0, 27.5] vs 0 [0, 4]; P = .11) study visits. Exercise volume was similar between groups (median, 115 [54, 225] vs 88 [28, 230] min/wk for exercise intervention vs standard of care; P = .52). Regardless of group, those who exercised <100 min/wk reported significantly higher symptom severity at the 1-month evaluation compared with those who exercised ≥100 min/wk (median, 1.5 [0, 7.5] vs 12 [4, 28]; P = .03). Exercising ≥160 min/wk successfully discriminated between those with and those without symptoms 1 month after study commencement (classification accuracy, 81%; sensitivity, 90%; specificity, 78%).

CONCLUSION

Greater exercise volume was associated with lower symptom burden after 1 month of study, and an exercise volume >160 min/wk in the first month of the study was the threshold associated with symptom resolution after the first month of the study. Because our observation on the association between exercise volume and symptom level is a retrospective and secondary outcome, it is possible that participants who were feeling better were more likely to exercise more, rather than the exercise itself driving the reduction in symptom severity.

Identifying degenerative effects of repetitive head trauma with neuroimaging: a clinically-oriented review

BACKGROUND AND SCOPE OF REVIEW

Varying severities and frequencies of head trauma may result in dynamic acute and chronic pathophysiologic responses in the brain. Heightened attention to long-term effects of head trauma, particularly repetitive head trauma, has sparked recent efforts to identify neuroimaging biomarkers of underlying disease processes. Imaging modalities like structural magnetic resonance imaging (MRI) and positron emission tomography (PET) are the most clinically applicable given their use in neurodegenerative disease diagnosis and differentiation. In recent years, researchers have targeted repetitive head trauma cohorts in hopes of identifying in vivo biomarkers for underlying biologic changes that might ultimately improve diagnosis of chronic traumatic encephalopathy (CTE) in living persons. These populations most often include collision sport athletes (e.g., American football, boxing) and military veterans with repetitive low-level blast exposure. We provide a clinically-oriented review of neuroimaging data from repetitive head trauma cohorts based on structural MRI, FDG-PET, Aβ-PET, and tau-PET. We supplement the review with two patient reports of neuropathology-confirmed, clinically impaired adults with prior repetitive head trauma who underwent structural MRI, FDG-PET, Aβ-PET, and tau-PET in addition to comprehensive clinical examinations before death.

REVIEW CONCLUSIONS

Group-level comparisons to controls without known head trauma have revealed inconsistent regional volume differences, with possible propensity for medial temporal, limbic, and subcortical (thalamus, corpus callosum) structures. Greater frequency and severity (i.e., length) of cavum septum pellucidum (CSP) is observed in repetitive head trauma cohorts compared to unexposed controls. It remains unclear whether CSP predicts a particular neurodegenerative process, but CSP presence should increase suspicion that clinical impairment is at least partly attributable to the individual's head trauma exposure (regardless of underlying disease). PET imaging similarly has not revealed a prototypical metabolic or molecular pattern associated with repetitive head trauma or predictive of CTE based on the most widely studied radiotracers. Given the range of clinical syndromes and neurodegenerative pathologies observed in a subset of adults with prior repetitive head trauma, structural MRI and PET imaging may still be useful for differential diagnosis (e.g., assessing suspected Alzheimer's disease).

Differences in Adolescent Symptom Reporting Following Motor Vehicle Accident Versus Sport-Related Concussion

OBJECTIVE

To characterize potential differences in youth concussion sustained in motor vehicle accident (MVA) versus sport-related concussion (SRC), hypothesizing that youth who sustain concussion in a MVA would endorse higher initial and persistent symptom scores compared to those with SRC, despite similar injury severity levels.

METHODS

Participants age 12-18 who sustained a concussion (i.e., Glasgow Coma Scale = 13-15) in a MVA (n = 35) were matched with SRC participants (n = 35) by sex, age, and days since injury. ANCOVA comparing initial postconcussion total symptom scores between the MVA and SRC groups were performed. Chi-square analysis with injury group by recovery time was used to determine whether youth who sustained concussion from MVA were more likely to endorse symptoms persisting >30 days at 3 months postinjury, and ANCOVA compared 3-month total symptom scores.

RESULTS

On average, the MVA group reported significantly higher initial postconcussion and more frequent persistent symptom scores compared to the SRC group.

CONCLUSIONS

This is the first known study to examine context of injury in youth concussion while matching for injury severity, age, sex, and days since injury. Findings suggest the context of injury is an important clinical variable related to initial reporting of symptoms and endorsement of symptoms lasting more than 30 days. Tailored interventions that consider the context of injury may facilitate symptom resolution.

Association of Previous Concussion with Hippocampal Volume and Symptoms in Collegiate-Aged Athletes

There is concern that previous concussion and contact-sport exposure may have negative effects on brain structure and function. Accurately quantifying previous concussion is complicated by the fact that multiple definitions exist, with recent definitions allowing for diagnosis based on the presence of symptoms alone (Concussion in Sport Group criteria; CISG) rather than the presence of acute injury characteristics such as alterations in mental status (American Congress of Rehabilitation Medicine criteria; ACRM). The goals of the current work were to determine the effects of previous concussion and contact-sport exposure on gray matter structure and clinical measures in healthy, young-adult athletes and determine the extent to which these associations are influenced by diagnostic criteria used to retrospectively quantify concussions. One-hundred eight collegiate-aged athletes were enrolled; 106 athletes were included in final analyses (age, 21.37 ± 1.69; 33 female). Participants completed a clinical battery of self-report and neurocognitive measures and magnetic resonance imaging to quantify subcortical volumes and cortical thickness. Semistructured interviews were conducted to measure exposure to contact sports and the number of previous concussions based on CISG and ACRM criteria. There was a significant association of concussion-related and psychological symptoms with previous concussions based on ACRM (ps < 0.05), but not CISG, criteria. Hippocampal volume was inversely associated with the number of previous concussions for both criteria (ps < 0.05). Findings provide evidence that previous concussions are associated with smaller hippocampal volumes and greater subjective clinical symptoms in otherwise healthy athletes and highlight the importance of diagnostic criteria used to quantify previous concussion.

Factors Associated With Clinical Recovery After Concussion in Youth Ice Hockey Players

Background:

The identification of factors associated with clinical recovery in youth after sports-related concussion could improve prognostication regarding return to play (RTP).

Purpose:

To assess factors associated with clinical recovery after concussion in youth ice hockey players.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Participants were part of a larger longitudinal cohort study (the Safe to Play study; N = 3353). Included were 376 ice hockey players (age range, 11-17 years) from teams in Calgary and Edmonton, Canada, with 425 physician-diagnosed ice hockey–related concussions over 5 seasons (2013-2018). Any player with a suspected concussion was referred to a sports medicine physician for diagnosis, and a Sport Concussion Assessment Tool (SCAT) form was completed. Time to clinical recovery was based on time between concussion and physician clearance to RTP. Two accelerated failure time models were used to estimate days to RTP clearance: model 1 considered symptom severity according to the SCAT3/SCAT5 symptom evaluation score (range, 0-132 points), and model 2 considered responses to individual symptom evaluation items (eg, headache, neck pain, dizziness) of none/mild (0-2 points) versus moderate/severe (3-6 points). Other covariates were time to physician first visit (≤7 and >7 days), age group (11-12, 13-14, and 15-17 years), sex, league type (body checking and no body checking), tandem stance (modified Balance Error Scoring System result ≥4 errors out of 10), and number of previous concussions (0, 1, 2, and ≥3).

Results:

The complete case analysis (including players without missing covariates) included 329 players (366 diagnosed concussions). The median time to clinical recovery was 18 days. In model 1, longer time to first physician visit (>7 days) (time ratio [TR], 1.637 [95% confidence interval (CI), 1.331-1.996]) and greater symptom severity (TR, 1.016 [95% CI, 1.012-1.020]) were significant predictors of longer clinical recovery. In model 2, longer time to first physician visit (TR, 1.698 [95% CI, 1.399-2.062]), headache (moderate/severe) (TR, 1.319 [95% CI, 1.110-1.568]), and poorer tandem stance (TR, 1.249 [95% CI, 1.052-1.484]) were significant predictors of longer clinical recovery.

Conclusion:

Medical clearance to RTP was longer for players with >7 days to physician assessment, poorer tandem stance, greater symptom severity, and moderate/severe headache at first visit.

Perceived Recovery and Self-Reported Functioning in Adolescents with Mild Traumatic Brain Injury: The Role of Sleep, Mood, and Physical Symptoms

Purpose: To determine the contributions of anxiety, depressive, and concussion symptoms and sleep quality to self-perceived recovery in adolescents with concussion.Method: Adolescents aged 12-20 (n = 298) completed anxiety, depression, concussion symptoms, and sleep measures at an initial concussion clinic visit and three-month follow-up. At follow-up, they reported self-perceived recovery as percent back to normal.Results: Injury-related factors alone did not predict self-perceived recovery (R²_Adj =.017, p =.074). More concurrent physical, mental health, and sleep symptoms explained 18.8% additional variance in poorer self-perceived recovery (R²_Adj Change =.188, p <.05). Physical symptoms (B_stand = -.292) and anxiety (B_stand = -.260) accounted for the most variance in self-perceived recovery.Conclusion: Post-concussive symptoms, in particular anxiety and self-reported physical symptoms, seem to characterize protracted recovery. Self-perceived recovery as an outcome measure may provide a more holistic understanding of adolescents' experiences after concussion.

Safety and Tolerability of an Innovative Virtual Reality-Based Deep Breathing Exercise in Concussion Rehabilitation: A Pilot Study

To examine the safety and tolerability of a virtual reality-based deep breathing exercise for children and adolescents who are slow to recover from concussion. Methods: Fifteen participants (ages 11 to 22; mean = 16.9 years) were recruited from a specialty concussion clinic within a tertiary care medical center. Participants completed a 5-min paced deep breathing exercise administered via a virtual reality headset. Results: Nearly all participants (93.3%) reported the experience was either positive or extremely positive. No participants reported significant discomfort or discontinued the exercise. Three participants reported a mild increase in headache, dizziness, or nausea. Participants reported significant decreases in stress (r =.57), tension (r =.73), fatigue (r =.73), and confusion (r =.67), with large effect sizes, following the deep breathing exercise. Conclusion: A brief, virtual reality-based deep breathing exercise is worthy of additional study as a rehabilitation component for children and adolescents with prolonged concussion recoveries.

Association Between Preinjury Symptoms and Postconcussion Symptoms at 4 Weeks in Youth

OBJECTIVE

To investigate whether preinjury physical, emotional, cognitive, and sleep symptoms on the Post-Concussion Symptoms Inventory (PCSI) are associated with persistent postconcussion symptoms (PPCS) at 4 weeks and whether any associations are moderated by sex or age.

STUDY SETTING AND PARTICIPANTS

A total of 3063 participants with acute concussion, presenting to 9 Canadian pediatric emergency departments, were enrolled from August 2013 to June 2015.

DESIGN

A planned secondary analysis of a prospective, multicenter cohort study (Predicting Persistent Post-concussive Problems in Pediatrics or 5P). Primary outcome was PPCS at 4 weeks, defined as 3 or more new or worsening individual symptoms compared with the preinjury score at 28 days on the PCSI. The association between preinjury scores and PPCS was analyzed with a multivariable logistic regression analysis that included preinjury, sex, age, sex × preinjury, and age × preinjury interactions as predictors. Missing baseline covariates were imputed.

RESULTS

A total of 2123 (n = 844 [39.8%] girls; median [IQR] age = 12.9 [10.7, 15.0] participants were included in the analysis. Preinjury physical symptom score was associated with PPCS at 4 weeks (χ2 = 13.87, df = 6, P = .031). The preinjury emotional score also contributed to the variability in PPCS (χ2 = 11.79, df = 6, P = .067). While girls reported higher preinjury physical, emotional, and cognitive scores than boys, neither sex nor age interacted with preinjury to predict PPCS at 4 weeks. Independent of age and sex, preinjury physical symptoms were associated with PPCS at 4 weeks (OR = 1.40; 95% CI, 1.15-1.70).

CONCLUSION

Preinjury physical symptoms are associated with the probability of having PPCS at 4 weeks postconcussion independent of age and sex. Providers should consider preinjury symptoms to inform prognosis and recovery management.

Sex differences in the Buffalo Concussion Treadmill Test in adolescents with acute sport-related concussion

OBJECTIVES

The Buffalo Concussion Treadmill Test (BCTT) is a safe and validated tool to assess exercise tolerance after sport-related concussion (SRC). Sex differences may affect the interpretation of this systematic exertion test in the concussed population, which is important for clinicians. The purpose of this study was to examine sex differences in BCTT performance in adolescents with acute SRC.

DESIGN

Prospective cohort.

METHODS

Male (n = 103, 15.3 ± 2 years) and female (n = 87, 15.1 ± 2 years) adolescents with SRC performed the BCTT within 10 days of injury. Heart rate (HR), HR threshold (HRt), Delta HR (difference between resting HR and HRt), symptom severity on Visual Analog Scale (VAS) and symptoms exacerbated on the BCTT were collected and compared.

RESULTS

Males had lower resting HR (M: 70.9 ± 12 vs F: 75.7 ± 13 bpm, p < 0.01) and reached a lower HRt than females (M: 134.7 ± 23 vs F: 141.5 ± 25 bpm, p = 0.05). Sexes did not differ on Delta HR (M: 63.8 ± 26 vs F: 65.9 ± 24 bpm, p = 0.57), total treadmill time (M: 9.3 ± 5 vs F: 8.4 ± 4 min, p = 0.20), maximum VAS (M: 5.0 ± 2 vs F: 5.4 ± 2, p = 0.18) or incidence of a change in VAS (M: 91% vs F: 94%, p = 0.43) on the BCTT.

CONCLUSIONS

Although males may reach symptom exacerbation at a slightly lower mean HRt than females on the BCTT within 10 days of SRC, the BCTT provides comparable information and both sexes reach symptom exacerbation at similar Delta HR.

Mental health after paediatric concussion: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis sought to rigorously examine mental health outcomes following paediatric concussion. To date, heterogeneous findings and methodologies have limited clinicians' and researchers' ability to meaningfully synthesise existing literature. In this context, there is a need to clarify mental health outcomes in a homogeneous sample, controlling for key methodological differences and applying a consistent definition of concussion across studies.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched Medline, Embase, PsycINFO, CINAHL, SportDiscus, Scopus and PubMed.

ELIGIBILITY

Peer-reviewed studies published between 1980 and June 2020 that prospectively examined mental health outcomes after paediatric concussion, defined as per the Berlin Consensus Statement on Concussion in Sport.

RESULTS

Sixty-nine articles characterising 60 unique samples met inclusion criteria, representing 89 114 children with concussion. Forty articles (33 studies) contributed to a random effects meta-analysis of internalising (withdrawal, anxiety, depression, post-traumatic stress), externalising (conduct problems, aggression, attention, hyperactivity) and total mental health difficulties across three time points post-injury (acute, persisting and chronic). Overall, children with concussion (n=6819) experienced significantly higher levels of internalising (g=0.41-0.46), externalising (g=0.25-0.46) and overall mental health difficulties compared with controls (g=0.18-0.49; n=56 271), with effects decreasing over time.

SUMMARY/CONCLUSIONS

Our review highlights that mental health is central to concussion recovery. Assessment, prevention and intervention of mental health status should be integrated into standard follow-up procedures. Further research is needed to clarify the mechanisms underlying observed relationships between mental health, post-concussion symptoms and other psychosocial factors. Results suggest that concussion may both precipitate and exacerbate mental health difficulties, thus impacting delayed recovery and psychosocial outcomes.

Clinical Outcomes of Pediatric Acute Sport- and Non-Sport-Related Concussions

OBJECTIVES

The objectives were to examine clinical characteristics, length of recovery, and the prevalence of delayed physician-documented recovery, compare clinical outcomes among those with sport-related concussion (SRC) and non-sport-related concussion (nSRC), and identify risk factors for delayed recovery.

METHODS

Included patients (8-18 years) were assessed ≤14 days post-injury at a multidisciplinary concussion program and diagnosed with an acute SRC or nSRC. Physician-documented clinical recovery was defined as returning to pre-injury symptom status, attending full-time school without symptoms, completing Return-to-Sport strategy as needed, and normal physical examination. Delayed physician-documented recovery was defined as >28 days post-injury.

RESULTS

Four hundred and fifteen patients were included (77.8% SRC). There was no difference in loss of consciousness (SRC: 9.9% vs nSRC: 13.0%, p = 0.39) or post-traumatic amnesia (SRC: 24.1% vs SRC: 31.5%, p = 0.15) at the time of injury or any differences in median Post-Concussion Symptom Scale scores (SRC: 20 vs nSRC: 23, p = 0.15) at initial assessment. Among those with complete clinical follow-up, the median physician-documented clinical recovery was 20 days (SRC: 19 vs nSRC: 23; p = 0.37). There was no difference in the proportion of patients who developed delayed physician-documented recovery (SRC: 27.7% vs nSRC: 36.1%; p = 0.19). Higher initial symptom score increased the risk of delayed physician-documented recovery (IRR: 1.39; 95% CI: 1.29, 1.49). Greater material deprivation and social deprivation were associated with an increased risk of delayed physician-documented recovery.

CONCLUSIONS

Most pediatric concussion patients who undergo early medical assessment and complete follow-up appear to make a complete clinical recovery within 4 weeks, regardless of mechanism.

Does Vestibular-Ocular-Motor (VOM) Impairment Affect Time to Return to Play, Symptom Severity, Neurocognition and Academic Ability in Student-Athletes following acute Concussion?

Introduction: Research indicates Sports-Related Concussion (SRC) impairs Vestibular-Ocular-Motor (VOM) function. The aim was to explore if VOM impairment correlates with longer Return To Play (RTP), symptom burden, neurocognitive performance and academic capability.Participants: 40 (61.4% male) Loughborough University, UK, rugby union student-athletes who sustained 42 SRCs.Methods: Student-athletes completed an assessment battery during pre-season (baseline), 2, 4, 8 and 14 days post-SRC and prior to RTP and were managed according to the rugby Football Union' community pathway.Outcome measures: Vestibular Ocular-Motor Screening (VOMS), Immediate Post-Concussion Assessment and Cognitive Test, Post-Concussion Symptom Scale, Perceived Academic Impairment Tool questionnaire and percentage of academic activities specifically missed due to SRC.Results: VOMS scores were significantly (p < 0.005) greater than baseline at all time points except RTP. Presence of VOM dysfunction at 14 days post-SRC significantly correlated with a longer RTP, greater symptom burden and increased odds ratio at 2, 4 and 8 days and academic time loss at 2, 4 and 8 days post-SRC.Conclusion: VOM impairment is associated with an increased symptom burden and impaired academic capability, and a longer time to RTP when present at 14 days post-SRC.

Are you missing a concussion by watching American football? Video analysis of ball location in a Division 1 football program

OBJECTIVE

Action in a football game occurs quickly. Medical staff can miss a sport-related concussion (SRC) if they do not observe it directly. The objective of this study is to determine if SRCs occur more frequently at ball than away from ball during gameplay. Game-specific concussion statistics can enhance medical provider care of athletes.

METHODS

We used gameplay videos of an NCAA Division I football program to analyze SRCs and determine the primary tackler or ball handler during each concussion play. We compared the relative risk of SRCs for the primary ball handlers/tacklers to that of the other 10 players on the same team during that play.

RESULTS

Over 10 seasons, 26 SRCs occurred at ball for the primary ball handler/tackler position (0.22 SRCs/game) versus 16 away from ball (0.13 SRCs/game). The relative risk of an SRC according to exposure (at ball) vs. no exposure (away from ball) was 16.2 (CI 8.7-30.2, P < .05). Special teams had more SRCs away from ball than at ball, but this was not significant (relative risk 3.32, CI 0.90-12.3, P > .05).

CONCLUSIONS

The study provides medical staff guidance to more efficiently identify in-game SRCs and supports evidence for rules changes.

Endocrine Responses to Sport-Related Brain Injury in Female Athletes: A Narrative Review and a Call for Action

Sport-related brain injury (SRBI) occurs when a blow to the head causes the brain to move back and forth in the skull, and can lead to neuroendocrine dysfunction. Research has shown that males and females experience and recover from SRBI differently, yet most of what is known regarding diagnosis, treatment, and recovery of SRBI is based on male normative data even though females meet or exceed incidence numbers of SRBIs compared to those of males. Females also have been known to have worse outcomes and a greater number of symptoms following SRBI than males. Research is limited as to why females have worse outcomes, but sex hormones have been suggested as a potential reason. SRBI may cause a dysregulation of the hypothalamic–pituitary–gonadal (HPG) axis, which is responsible for regulating the sex hormones estrogen and progesterone. Initial research has shown that SRBI may suppress estrogen and progesterone, and the concentration of these sex hormones could be indicative of injury severity and recovery trajectory. This review discusses the sex-specific differences in SRBI and also the future direction of research that is needed in order to identify the repercussions of SRBIs for female athletes, which will eventually lead to better clinical treatment, sideline care, and recovery profiles.

Fear avoidance behavior in youth with poor recovery from concussion: measurement properties and correlates of a new scale

The objective of the current study was to develop a measure of fear avoidance behavior after concussion for youth and parent respondents and examine its basic psychometric properties and correlates. Children (N = 51) who were seen in a hospital concussion clinic after sustaining a concussion (M = 7.6 months, SD = 7.01) and their primary caregiver (N = 51)completed self- and informant-report measures of fear avoidance (Pediatric Fear Avoidance Behavior after Traumatic Brain Injury Questionnaire; PFAB-TBI), post-concussion symptoms (Health Behavior Inventory), emotional distress (Strengths and Difficulties Questionnaire), and quality of life (Pediatric Quality of Life Inventory Version 4.0). The self- and informant-report PFAB-TBI scores were moderately correlated (r = 0.51, p < 0.001). Neither measure demonstrated floor or ceiling effects. Both had strong internal consistency (Cronbach's α = 0.87 and 0.89, respectively). The PFAB-TBI self-report was positively correlated with somatic symptoms (r = 0.37), emotional distress (r = 0.39), and negatively associated with quality of life (r = -0.57). The PFAB-TBI informant-report was positively associated with informant reported somatic symptoms (r = 0.52) and emotional distress (r = .50) Overall, the PFAB-TBI has desirable basic measurement properties and expected correlations with clinical outcomes. This measure can potentially help clinicians and researchers better understand the impacts of fear avoidance behavior after pediatric concussion.

Selective head-neck cooling after concussion shortens return-to-play in ice hockey players

We aimed to investigate whether selective head–neck cooling could shorten recovery after sports-related concussions (SRCs). In a nonrandomized study of 15 Swedish professional ice hockey teams, 29 concussed players received immediate head and neck cooling for ≥30 min (initiated at 12.3 ± 9.2 min post-SRC by a portable cooling system), and 52 SRC controls received standard management. Players receiving head–neck cooling had shorter time to return-to-play than controls (7 vs 12.5 days, p < 0.0001), and 7% in the intervention group versus 25% in the control group were out of play for ≥3 weeks (p = 0.07). Immediate selective head–neck cooling is a promising option in the acute management of SRC that should be addressed in larger cohorts.

Sex-Based Differences in Symptoms with Mouthguard Use Following Pediatric Sport-Related Concussion

CONTEXT

Current evidence regarding the protective effect of mouthguard use on symptom severity in children and adolescents who sustain sport-related concussions is insufficient to make clinical recommendations.

OBJECTIVE

To compare the association between mouthguard-use and symptoms stratified by sex in the first 4-weeks after pediatric sport-related concussion. We hypothesized that mouthguard-use would be associated with lower symptoms.

DESIGN

Prospective cohort study.

SETTING

Nine Canadian pediatric emergency departments (EDs).

PATIENTS

Children aged 5-18 years presenting ≤48 hours of concussion sustained during a collision or contact sport.

MAIN OUTCOME MEASURES

Injury characteristics were collected using the Acute Concussion Evaluation. Primary outcome measure was symptom score (0-6), measured using age-appropriate versions (5-7 years; 8-12 years; 13-18 years) of the Post-Concussion Symptom Inventory. Independent variable was time postconcussion (at initial assessment, 1-, 2-, 4, weeks).

RESULTS

Of 1019 children (73% male; median [IQR] age=13.43[11.01,15.27] years), 42% wore a mouthguard at time of injury. There was no significant group by sex by time interaction for symptoms (χ23=0.27; p=.965). Male mouthguard users reported similar symptom scores in the ED (diff=-0.07; 95%CI:-0.23,0.09), at week-1 (diff=-0.02; 95%CI:-0.18,0.14), week-2 (diff=-0.03; 95%CI:-0.19,0.13), and week-4 (diff=-0.13; 95%CI:-0.29,0.04) compared with males who didn't wear a mouthguard. Female mouthguard users reported minimally higher symptom scores at week-1 compared with non-mouthguard users (diff=0.29; 95%CI:0.01,0.56). Symptom scores were not significantly different for females who wore a mouthguard and those who didn't in the ED (diff=0.22; 95%CI:-0.04,0.48), at week-2 (diff=0.22; 95%CI:-0.06,0.51), or week-4 (diff=0.08; 95%CI:-0.20,0.36).

CONCLUSION

Wearing a mouthguard at time of injury is not associated with reduced acute and subacute symptoms after sport-related concussion in either males or females who were treated in the ED compared with those who did not wear a mouthguard. Athletes are still encouraged to wear a mouthguard during sports since overwhelming evidence supports their use in preventing dental injuries.

Repetitive Mild Traumatic Brain Injury in a Perinatal Nicotine Exposure Mouse Model of Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) increases the risk for concussion or mild traumatic brain injury (mTBI). At the same time, recommendations for the management of ADHD include participation in sports and other organized physical activities, including those that carry an increased risk of mTBI. Very little work has been done to determine the extent to which untreated ADHD adversely impacts behavioral outcomes of repeated mild concussions. Here, we used a perinatal nicotine exposure (PNE) mouse model of ADHD combined with a closed-head, repetitive mTBI model. The PNE mouse model carries significant construct, face, and predictive validity as a preclinical model of ADHD. Two-month-old PNE and control mice were subjected to closed-head repetitive mTBI or sham procedure once daily for 5 days. Object-based attention, novel object recognition memory, spatial working memory, and depression-like behavior were analyzed 1 day and 2 weeks following repeated mTBI. Consistent with our previous reports, mice in the PNE group showed significant deficits in object-based attention and working memory prior to mTBI. These deficits persisted following the repeated mTBI. Repeated mTBI produced a transient attention deficit in the control group but did not exacerbate the attention deficit that is characteristic of the PNE group. Although neither PNE nor repetitive mTBI alone influenced immobility in the tail suspension test, when PNE mice were subjected to mTBI, there was a transient increase in this measurement suggesting a synergistic effect of ADHD and mTBI on depression-like behavior. Thus, our data using the PNE mouse model suggest that ADHD may be a risk factor for transient depression following repeated mTBI and that repeated mTBI may be a risk factor for transient attention deficit.

Sport Contact Level Affects Post-Concussion Neurocognitive Performance in Young Athletes

OBJECTIVE

Contact level affects the incidence of sports-related concussion. However, the effects of contact level on injury severity and recovery are less clear and are the focus of this study.

METHOD

Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for athletes aged 12-22 was performed at baseline (n = 10,907 for 7,058 athletes), after suspected concussion determined by physicians or athletic trainers (n = 5,062 for 4,419 athletes), and during follow-up visits (n = 3,264 for 2,098 athletes). Athletes played contact/collision (CC), limited contact (LC), and noncontact (NC) sports. Injury incidence, severity, and recovery were measured using raw and change from baseline neurocognitive test scores. Comparisons between groups used univariate analysis and multivariable regression controlling for demographic variables.

RESULTS

Compared to CC athletes, LC and NC athletes showed decreased suspected concussion incidence. At initial post-injury testing, all neurocognitive test scores were similar between groups except changes from baseline for processing speed were improved for LC compared to CC athletes. Upon follow-up testing, raw neurocognitive scores were better for NC compared to the contact collision athletes in verbal memory, processing speed, total symptom score, migraine cluster, cognitive cluster, and neuropsychiatric cluster scores. For change from baseline scores, LC athletes exhibited better performance on verbal memory, processing speed, and reaction time but also showed higher neuropsychiatric scores than CC athletes.

CONCLUSION

Neurocognitive scores between contact levels were similar at the first post-injury test. However, follow up showed many improved scores and symptoms for limited and NC sports compared to CC sports, which may indicate faster recovery.

Predicting Sport-related mTBI Symptom Resolution Trajectory Using Initial Clinical Assessment Findings: A Retrospective Cohort Study

OBJECTIVES

To identify which aspects of initial clinical assessment for sport-related mild traumatic brain injury (SR-mTBI) predict whether an athlete achieves symptom resolution within 14 days of the injury.

RESEARCH DESIGN

Retrospective cohort study using prospectively collected data.

METHODS

Clinical assessment data were collected from 568 patients diagnosed with SR-mTBI at a single medical clinic between February 2017 and December 2018. Demographic data, medical history, SCAT-5 testing, and physician notes were included in the data set. Data were processed and analysed to identify a shortlist of predictor variables to develop a logistic regression model to discriminate between SR-mTBI symptom resolution that occurred in ≤ 14-days or > 14-days. The data were randomly divided into model development and validation subsamples. The top 15 models were analysed to determine the predictor variables to be included in the final logistic regression model. The final model was then applied to the validation subsample.

RESULTS

Half of the athlete participants in this study experienced > 14-day symptom resolution. The final logistic regression model included sex, symptom reporting at initial assessment and presentation with a physiological predominant symptom cluster. The model accounted for 0.90 and 0.85 of the area under the curve and predicted recovery trajectory with 81% and 76% accuracy for the training and validation subsamples, respectively.

CONCLUSIONS

Being female, reporting a higher Positive Symptom Total at initial assessment, and being less likely to have a physiological predominant symptom cluster at initial assessment predicted > 14 versus ≤ 14-day SR-mTBI symptom resolution with a high level of accuracy.

The ENIGMA sports injury working group:- an international collaboration to further our understanding of sport-related brain injury

Sport-related brain injury is very common, and the potential long-term effects include a wide range of neurological and psychiatric symptoms, and potentially neurodegeneration. Around the globe, researchers are conducting neuroimaging studies on primarily homogenous samples of athletes. However, neuroimaging studies are expensive and time consuming, and thus current findings from studies of sport-related brain injury are often limited by small sample sizes. Further, current studies apply a variety of neuroimaging techniques and analysis tools which limit comparability among studies. The ENIGMA Sports Injury working group aims to provide a platform for data sharing and collaborative data analysis thereby leveraging existing data and expertise. By harmonizing data from a large number of studies from around the globe, we will work towards reproducibility of previously published findings and towards addressing important research questions with regard to diagnosis, prognosis, and efficacy of treatment for sport-related brain injury. Moreover, the ENIGMA Sports Injury working group is committed to providing recommendations for future prospective data acquisition to enhance data quality and scientific rigor.

Concussion History and Balance Performance in Adolescent Rugby Union Players

BACKGROUND

Sports-related concussion is a worldwide problem. There is a concern that an initial concussion can cause prolonged subclinical disturbances to sensorimotor function that increase the risk of subsequent injury. The primary aim of this study was to examine whether a history of sports-related concussion has effects on static and dynamic balance performance in adolescent rugby players.

HYPOTHESIS

Dynamic balance would be worse in players with a history of concussion compared with those with no history of concussion.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Male adolescent rugby players aged 14 to 18 years from 5 schools were recruited before the start of the 2018-2019 playing season. Participants completed questionnaires and physical tests, including dynamic Y balance and single-leg static balance (eyes closed) tests, while performing single and dual tasks. Dynamic balance was assessed using inertial sensor instrumentation. Dependent variables were normalized reach distance and the sample entropy (SEn) of the 3 axes (x, y, and z).

RESULTS

Of the 195 participants, 100 reported a history of concussion. Those with a history of concussion demonstrated higher SEn in all directions, with highest values during anterior (standardized mean difference [SMD], 0.4; 95% CI, 0.0-0.7; P = .027) and posteromedial (SMD, 0.5; 95% CI, 0.2-0.9; P = .004) reach directions compared with those with no history. There was no difference between groups (concussion history vs control) in traditional Y balance reach distances in the anterior or posteromedial directions or single-leg static balance during both single- (P = .47) and dual-task (P = .67) conditions.

CONCLUSION

Adolescent rugby union athletes with a history of concussion had poorer dynamic balance during performance tasks compared with healthy controls. Static single-leg balance tests, either single or dual task, may not be sensitive enough to detect sensorimotor deficits in those with a history of concussion.

A Genome-wide Association Study for Concussion Risk

PURPOSE

This study aimed to screen the entire genome for genetic markers associated with risk for concussion.

METHODS

A genome-wide association analyses was performed using data from the Kaiser Permanente Research Bank and the UK Biobank. Concussion cases were identified based on electronic health records from the Kaiser Permanente Research Bank and the UK Biobank from individuals of European ancestry. Genome-wide association analyses from both cohorts were tested for concussion using a logistic regression model adjusting for sex, height, weight, and race/ethnicity using allele counts for single nucleotide polymorphisms. Previously identified genes within the literature were also tested for association with concussion.

RESULTS

There were a total of 4064 cases of concussion and 291,472 controls within the databases, with two single nucleotide polymorphisms demonstrating a genome-wide significant association with concussion. The first polymorphism, rs144663795 (P = 9.7 × 10-11; OR = 2.91 per allele copy), is located within the intron of SPATA5. Strong, deleterious mutations in SPATA5 cause intellectual disability, hearing loss, and vision loss. The second polymorphism, rs117985931 (P = 3.97 × 10-9; OR = 3.59 per allele copy), is located within PLXNA4. PLXNA4 plays a key role is axon outgrowth during neural development, and DNA variants in PLXNA4 are associated with risk for Alzheimer's disease. Previous investigations have identified five candidate genes that may be associated with concussion, but none showed a significant association in the current model (P < 0.05).

CONCLUSION

Two genetic markers were identified as potential risk factors for concussion and deserve further validation and investigation of molecular mechanisms.

Concussion-Symptom Rating Correlation Between Pediatric Patients and Their Parents

CONTEXT

Understanding how parents and their children perceive concussion symptoms may provide insights into optimal concussion-management strategies.

OBJECTIVE

To examine patient-parent correlations and agreement on concussion-symptom ratings, to identify differences in patient-parent symptom reporting between children (8-12 years of age) and adolescents (13-18 years of age), and to evaluate the correlation between patient and parent initial symptom-severity ratings with symptom duration and return-to-play time.

DESIGN

Cross-sectional study.

SETTING

Primary care sports medicine clinic.

PATIENTS OR OTHER PARTICIPANTS

A total of 267 patients aged 8 to 18 years seen for care within 21 days of sustaining a concussion. Patients were classified as children (n = 65; age = 11.3 ± 1.4 years; age range, 8-12 years) or adolescents (n = 202; age = 15.5 ± 1.4 years; age range, 13-18 years).

MAIN OUTCOME MEASURE(S)

Each patient and his or her parent (or legal guardian) completed a concussion-symptom-frequency inventory, the Health and Behavior Inventory (HBI), at the initial postinjury examination. Patients were followed until they no longer reported concussion symptoms (symptom-resolution time) and were allowed to return to unrestricted sport participation (return-to-play time).

RESULTS

At the initial examination (8.9 ± 5.2 days postinjury), the symptom-frequency correlation between children and their parents was high (rs = 0.88; 95% confidence interval [CI] = 0.80, 0.95). Adolescents' symptom-frequency reports were also highly correlated with those of their parents (rs = 0.78; 95% CI = 0.71, 0.85). However, the child-parent correlation was higher than the adolescent-parent agreement (z = 2.21, P = .03). Greater patient (consolidated child and adolescent) HBI ratings were associated with longer symptom-resolution times (coefficient = 0.019; 95% CI = 0.007, 0.031; P = .002) and longer return-to-play times (coefficient = 0.012; 95% CI = 0.002, 0.022; P = .02), whereas parent HBI ratings were not.

CONCLUSIONS

Our findings may help to set expectations regarding concussion-symptom durations and return-to-play timing for pediatric patients and their families. Given the patient-parent correlations in our sample, substantial reporting discrepancies between patients and their parents may be a relevant factor for clinicians to investigate further during concussion evaluations.

Children with ADHD Have a Greater Lifetime History of Concussion: Results from the ABCD Study

This case-control study using baseline data from the population cohort Adolescent Brain Cognitive Development (ABCD) Study^® compared lifetime history of concussion between children with and without attention-deficit/hyperactivity disorder (ADHD). We hypothesized that children with ADHD would have a greater lifetime history of concussion than children without ADHD. Children were recruited from schools across the United States, sampled to provide strong generalizability to the US population. The current sample included 10,585 children (age: mean = 9.9; standard deviation = 0.6; range 9-10 years; 48.9% girls; 64.6% White), including 1085 with ADHD and 9500 without ADHD. The prevalence of prior concussion among children with ADHD was 7.2% (95% CI: 6.6-7.8%) compared with 3.2% (3.1-3.3%) among children without ADHD, meaning current ADHD status was associated with twice the odds of experiencing a prior concussion [χ² = 44.54; p < 0.001; odds ratio = 2.34 (1.81-3.03)]. No significant differences were observed in proportion of boys and girls with ADHD who had a prior concussion history. The number of current ADHD symptoms were not meaningfully associated with prior concussion history. Lower socioeconomic status was associated with lower rates of reported concussion, but not differentially in association with ADHD. ADHD is associated with twice the lifetime prevalence of prior concussion before age 11 among children from the general U.S. population. Boys and girls with ADHD did not differ in proportions with prior concussion and concussion history was not related to the number of ADHD symptoms reported by parents.

Factors Associated with Quality of Life in Adults with Persistent Post-Concussion Symptoms

OBJECTIVE

To assess demographic, clinical, and injury characteristics associated with health-related quality of life (HRQOL) in adults with persistent post-concussion symptoms (PPCS).

METHODS

Adults with PPCS presenting to a specialized brain injury clinic completed demographic, injury, and clinical outcome questionnaires at the initial clinic assessment. Clinical outcome measures were collected including the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder Scale-7 (GAD-7), and the Fatigue Severity Scale (FSS). HRQOL was measured using the Quality of Life after Brain Injury (QOLIBRI) questionnaire. Stepwise hierarchical multiple regression analysis adjusting for age, sex, and months since injury was used to determine associations between quality of life and clinical outcome measures.

RESULTS

Overall, 125 participants were included. The PHQ-9, FSS, and GAD-7 were significant predictors of QOLIBRI scores (R2 = 0.481, p < .001), indicating that participants with higher levels of depressive symptoms, fatigue, and anxiety reported poorer HRQOL. The PHQ-9 score was the strongest predictor, accounting for 42.0% of the variance in QOLIBRI scores. No demographic or injury characteristics significantly predicted QOLIBRI scores. There was a high prevalence of depressive symptoms with 72.8% of participants having PHQ-9 scores ≥ 10.

CONCLUSION

Among patients with PPCS, mental health and fatigue are important contributors to HRQOL. As there is a high burden of mood disorders and fatigue in this population, targeted treatments for these concerns may impact the quality of life.

The Influence of Timing of Reporting and Clinic Presentation on Concussion Recovery Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Identifying risk factors for prolonged recovery following concussion can assist clinicians with appropriate management strategies. It is thought that athletes who continue to participate following a hit to the head or body may take longer to recover following a concussion diagnosis.

OBJECTIVE

To systematically review the body of literature regarding the effect of delayed reporting and delayed presentation to medical providers on concussion recovery times.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

PubMed, Ovid Medline, SPORTDiscus, Cochrane Central Register of Controlled Trials and hand searches of reference lists. All the searches were performed in April 2020.

ELIGIBILITY CRITERIA FOR SELECTED STUDIES

Studies included an investigation of immediate versus delayed reporting or early versus late presentation following a concussion, were published in the past ten years, and were level 4 evidence or higher.

RESULTS

12 studies were included. Patients who continued play or delayed reporting their concussion had significantly longer recovery times (standardized mean difference = 0.36 days (95%CI 0.066, 0.662) than those who immediately reported or were removed from play (p = 0.017). Expressed in raw scores, those who immediately reported recovered in 5.4 days (95% CI - 10.14, - 0.75) fewer than delayed reporters. Comparable results were found for post-concussion symptom scores (p = 0.034) with immediate reporters demonstrating lower symptom severity scores. Our qualitative synthesis found patients who presented earlier to a concussion specialist tended to recover faster than those who presented later.

CONCLUSIONS

Patients who delayed reporting or continued play had longer recovery times compared to their immediately-reporting peers. Providers should ask concussion patients approximately how long they waited to report their injury, and also focus educational efforts on encouraging immediate reporting of concussion.

Evaluation of the vestibular and ocular motor screening (VOMS) as a prognostic tool for protracted recovery following paediatric sports-related concussion

Objective

To understand the relationship between initial vestibular and ocular motor screening (VOMS) and recovery time, and the utility of VOMS to screen for protracted recovery in youth/adolescent patients with sport-related concussion (SRC).

Methods

Participants (8–18 years) who were diagnosed with an SRC within 7 days of the injury were administered the VOMS test by certified medical personnel. Recovery time (days) and protracted recovery (>30 days) were the primary outcomes. Multivariable regression models were used to evaluate the association between VOMS symptom provocation and (1) recovery time (days) and (2) protracted recovery. Measures of VOMS validity, predictive ability and receiver operator curves were used to assess VOMS as a prognostic tool to accurately classify a normal/protracted recovery.

Results

After adjustment, any symptom provocation across all VOMS domains was associated (p<0.05) with greater recovery time, except the convergence test (p=0.08) in females. All VOMS test thresholds (≥1 to ≥10) in males and (≥1 to ≥5) in females were associated (p<0.05) with recovery time. However, the VOMS test performed poorly among males (receiver operating characteristic (ROC) area=0.66) and failed among females (ROC area=0.56) as a prognostic tool to identify those that will have a normal/protracted recovery.

Conclusion

In this sample, overall, the VOMS test was associated with recovery time (days); however, the VOMS was not a valid stand-alone prognostic tool to identify a delayed recovery, but may be useful in combination with other concussion symptomology assessments. Future studies should confirm these findings in larger samples while taking into consideration other comorbid factors that may influence recovery time.

Concussion in the Athletic Training Room: a Team Physician Narrative

PURPOSE OF THE REVIEW

Concussion evaluation and management has changed significantly. Understanding proper recognition, evaluation, and management allows for improved provision of care to patients. This paper will approach this topic from a sideline to training room management versus the traditional clinic evaluation RECENT FINDINGS: Research is continuing to refine and examine tools to assist in proper concussion evaluation. Concussion recovery protocols are becoming more conservative as patients are taking longer to recover than previously thought. Treatment of concussion is becoming more sophisticated and patient involved. Concussion research has increased dramatically over the last 30 years changing our approach to diagnosis and treatment. The area of concussion will continue to evolve as research continues to look at effective tools and markers for diagnosis and effective treatment protocols become substantiated through research.

Child- compared with parent-report ratings on psychosocial measures following a mild traumatic brain injury among youth with persistent post-concussion symptoms

Primary Objective: To compare child- and parent-report ratings on the Health Behavior Inventory, Revised Child Anxiety and Depression Scale-Short Version (anxiety subscale), Patient Health Questionnaire-9, and Pediatric Quality of Life Inventory^TM among children with persistent post-concussive symptoms following a sports- or recreation-related concussion, overall and by child age and gender.Research Design: Cross-sectional study examining baseline data from a randomized, comparative effectiveness trial.Methods and Procedures: Inter-rater reliability was assessed using two-way random effects model (absolute agreement) intraclass correlations, correlations were examined using Spearman's rho, mean differences were determined using paired t-tests, and agreement was examined using Bland-Altman plots.Main Outcomes and Results: The final analytic sample was 200 parent-child dyads [child M_age = 14.7 (95% CI: 14.5, 15.0)]. Reliability and correlations were modest overall. When considering child age and gender, reliability ranged from poor to excellent (-1.01-0.95) and correlations ranged from weak to strong (-0.64-0.94). Overall, children reported more symptoms but better functioning than parents, and mean differences in scores were greater among females (versus males) and ages 16-18 (versus younger groups).Conclusions: Findings should inform the use and interpretation of psychosocial measures when developing appropriate youth concussion treatment plans.

Traumatic brain injury and forensic evaluations: Three case studies of U.S. asylum-seekers

Traumatic brain injuries are common among refugees and asylum-seekers and can result from a range of etiologies, including intimate partner violence, gang violence, war-related trauma, and torture. Regardless of the cause, these injuries often result in a host of neuropsychiatric and other symptoms that may complicate individuals' subsequent health outcomes. For asylum-seekers, documenting prior head trauma is essential to the legal process, since traumatic brain injuries and their subsequent effects on memory and cognition may affect the ability to provide thorough testimony. Using three case vignettes, we explore how to approach the forensic evaluation of asylum-seekers with a history of traumatic brain injury, illustrating the range of etiologies and sequelae of traumatic brain injury in this complex population.

Do male and female adolescents report symptoms differently after concussion?

We investigated sex-based differences in the presence and severity of aggregated symptom indicators as well as individual concussion symptoms.Materials and Methods: A cross-sectional examination of sex differences in symptoms reported by adolescents upon initial concussion evaluation at a concussion clinic. Nine hundred and eighty-six adolescents completed the Sport Concussion Assessment Tool (SCAT5) symptom checklist. Chi-square and Mann-Whitney U tests were used for differences in the presence and severity of symptoms, respectively. Sex differences in global indices of symptom distress were compared.Results: Females endorsed more symptoms (Female: Median (M)=15, Interquartile range (IQR):9-18 vs. Male: M=11, IQR: 6-15, p<0.001) and a greater total symptom score (Female: M=37, IQR:16-45 vs. Male: M=20, IQR:8-39). After False Discovery Rate (FDR) adjustment, females endorsed the presence of 21 of 22 individual symptoms more frequently than males (p≤ 0.039), with greater symptom severity for 20 of 22 individual symptoms (p≤0.036). Moderate ESs were observed for sex-based differences in the total symptom score and the global severity index. Small ESs was observed for differences in most individual symptoms.Conclusions: The greater frequency and severity of concussion symptoms reported by female adolescents highlights the importance of considering sex as a modifier for the management of concussion.