Abstract: To explore the factors involved in athletes being ready (or not) to return to sport (RTS) after sport-related concussion (SRC). Design: Qualitative, semistructured interviews. Setting : Videoconference. Participants : Twenty-two sport-injury stakeholders involved in contact and collision sports at various levels of competition (high school, university, professional), including: formerly concussed athletes (n = 4), coaches (n = 5), athletic therapists (n = 5), physiotherapists (n = 4), nurse practitioner (n = 1), and sports medicine physicians (n = 3). Interventions: N/A. Main Outcome Measures: We included questions in the interview guide regarding factors participants believed were involved in athletes being ready (or not ready) to RTS after a concussion. Results: Participants described physical (concussion symptoms, return to pre-injury fitness), behavioral (changes in behavior, avoidance, malingering), psychological (individual factors, cognitive appraisals, mental health), and social (isolation, social support, communication, pressure) factors that they believed were involved in athletes being ready to RTS after SRC. Conclusions: The graduated RTS strategy outlined in the most recent Concussion in Sport Group consensus statement focuses on physical aspects involved in being ready to RTS, which does not address behavioral, psychological, and social factors, which were identified by participants as being related to returning to sport post-SRC. More research is needed to determine whether the additional factors outlined in this study are relevant among larger samples of athletes, coaches, and healthcare professionals.

Abstract: 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 less severe symptoms. Design Prospective cohort study. Setting Nine Canadian pediatric emergency departments (EDs). Patients or Other Participants Children aged 5 to 18 years who were assessed within 48 hours of concussions sustained during a collision or contact sport. Main Outcome Measure(s) Injury characteristics were collected using the Acute Concussion Evaluation. The primary outcome measure was symptom score (range = 0–6), measured using age-appropriate versions (5–7, 8–12, or 13–18 years) of the Post-Concussion Symptom Inventory. The independent variable was time postconcussion (initial assessment and 1, 2, and 4 weeks). Results Of 1019 children (73% male; median [interquartile range] age = 13.43 years [11.01–15.27 years] ), 42% wore a mouthguard at the time of injury. No significant group-by-sex-by-time interaction was present for symptoms (\(\def\upalpha{\unicode[Times]{x3B1}}\)\(\def\upbeta{\unicode[Times] {x3B2}}\)\(\def\upgamma{\unicode[Times]{x3B3}}\)\(\def\updelta{\unicode[Times] {x3B4}}\)\(\def\upvarepsilon{\unicode[Times]{x3B5}}\)\(\def\upzeta{\unicode[Times] {x3B6}}\)\(\def\upeta{\unicode[Times]{x3B7}}\)\(\def\uptheta{\unicode[Times] {x3B8}}\)\(\def\upiota{\unicode[Times] {x3B9}}\)\(\def\upkappa{\unicode[Times]{x3BA}}\)\(\def\uplambda{\unicode[Times] {x3BB}}\)\(\def\upmu{\unicode[Times]{x3BC}}\)\(\def\upnu{\unicode[Times] {x3BD}}\)\(\def\upxi{\unicode[Times]{x3BE}}\)\(\def\upomicron{\unicode[Times] {x3BF}}\)\(\def\uppi{\unicode[Times]{x3C0}}\)\(\def\uprho{\unicode[Times] {x3C1}}\)\(\def\upsigma{\unicode[Times]{x3C3}}\)\(\def\uptau{\unicode[Times] {x3C4}}\)\(\def\upupsilon{\unicode[Times]{x3C5}}\)\(\def\upphi{\unicode[Times] {x3C6}}\)\(\def\upchi{\unicode[Times]{x3C7}}\)\(\def\uppsy{\unicode[Times] {x3C8}}\)\(\def\upomega{\unicode[Times]{x3C9}}\)\(\def\bialpha{\boldsymbol{\alpha}}\)\(\def\bibeta{\boldsymbol{\beta}}\)\(\def\bigamma{\boldsymbol{\gamma}}\)\(\def\bidelta{\boldsymbol{\delta}}\)\(\def\bivarepsilon{\boldsymbol{\varepsilon}}\)\(\def\bizeta{\boldsymbol{\zeta}}\)\(\def\bieta{\boldsymbol{\eta}}\)\(\def\bitheta{\boldsymbol{\theta}}\)\(\def\biiota{\boldsymbol{\iota}}\)\(\def\bikappa{\boldsymbol{\kappa}}\)\(\def\bilambda{\boldsymbol{\lambda}}\)\(\def\bimu{\boldsymbol{\mu}}\)\(\def\binu{\boldsymbol{\nu}}\)\(\def\bixi{\boldsymbol{\xi}}\)\(\def\biomicron{\boldsymbol{\micron}}\)\(\def\bipi{\boldsymbol{\pi}}\)\(\def\birho{\boldsymbol{\rho}}\)\(\def\bisigma{\boldsymbol{\sigma}}\)\(\def\bitau{\boldsymbol{\tau}}\)\(\def\biupsilon{\boldsymbol{\upsilon}}\)\(\def\biphi{\boldsymbol{\phi}}\)\(\def\bichi{\boldsymbol{\chi}}\)\(\def\bipsy{\boldsymbol{\psy}}\)\(\def\biomega{\boldsymbol{\omega}}\)\(\def\bupalpha{\bf{\alpha}}\)\(\def\bupbeta{\bf{\beta}}\)\(\def\bupgamma{\bf{\gamma}}\)\(\def\bupdelta{\bf{\delta}}\)\(\def\bupvarepsilon{\bf{\varepsilon}}\)\(\def\bupzeta{\bf{\zeta}}\)\(\def\bupeta{\bf{\eta}}\)\(\def\buptheta{\bf{\theta}}\)\(\def\bupiota{\bf{\iota}}\)\(\def\bupkappa{\bf{\kappa}}\)\(\def\buplambda{\bf{\lambda}}\)\(\def\bupmu{\bf{\mu}}\)\(\def\bupnu{\bf{\nu}}\)\(\def\bupxi{\bf{\xi}}\)\(\def\bupomicron{\bf{\micron}}\)\(\def\buppi{\bf{\pi}}\)\(\def\buprho{\bf{\rho}}\)\(\def\bupsigma{\bf{\sigma}}\)\(\def\buptau{\bf{\tau}}\)\(\def\bupupsilon{\bf{\upsilon}}\)\(\def\bupphi{\bf{\phi}}\)\(\def\bupchi{\bf{\chi}}\)\(\def\buppsy{\bf{\psy}}\)\(\def\bupomega{\bf{\omega}}\)\(\def\bGamma{\bf{\Gamma}}\)\(\def\bDelta{\bf{\Delta}}\)\(\def\bTheta{\bf{\Theta}}\)\(\def\bLambda{\bf{\Lambda}}\)\(\def\bXi{\bf{\Xi}}\)\(\def\bPi{\bf{\Pi}}\)\(\def\bSigma{\bf{\Sigma}}\)\(\def\bPhi{\bf{\Phi}}\)\(\def\bPsi{\bf{\Psi}}\)\(\def\bOmega{\bf{\Omega}}\)\({\rm{\chi }}_3^2\) = 0.27; P = .965). Male mouthguard users reported similar symptom scores in the ED (difference in Post-Concussion Symptom Inventory Δ scores [diff] = −0.07; 95% CI = −0.23, 0.09) and at weeks 1 (diff = −0.02; 95% CI = −0.18, 0.14), 2 (diff = −0.03; 95% CI = −0.19, 0.13), and 4 (diff = −0.13; 95% CI = −0.29, 0.04) compared with males who did not wear a mouthguard. Female mouthguard users described minimally higher symptom scores at week 1 compared with non-mouthguard users (diff = 0.29; 95% CI = 0.01, 0.56). In the ED, symptom scores were not different for females who wore a mouthguard and those who did not (diff = 0.22; 95% CI = −0.04, 0.48) or at weeks 2 (diff = 0.22; 95% CI = −0.06, 0.51) or 4 (diff = 0.08; 95% CI = −0.20, 0.36). Conclusions Wearing a mouthguard at the time of injury was not associated with reduced acute or 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 mouthguards during sports because overwhelming evidence supports their use in preventing dental injuries.

Abstract: We aimed to examine the risk of concussion in children with a previous history of concussion. Design Systematic review and meta-analysis. The primary outcome was number of children with and without a previous lifetime history of concussion who sustained a diagnosed concussion within each study period. Risk of bias was assessed using the Newcastle-Ottawa Scale. A random effects model was used to estimate a pooled risk ratio (RR) with corresponding 95% CIs; results were summarised in forest plots. Data sources Four electronic databases (MEDLINE, Embase, CINAHL, SPORTDiscus) and selected reference lists were searched (PROSPERO registration No CRD42019135462). Eligibility criteria Original English language peer-reviewed publications that compared concussion risk in children aged 5–18 years with and without a previous concussion history in which risk estimates were reported or able to be calculated. Results Of 732 identified studies, 7 studies representing 23 411 children (risk of bias range, 7–9; maximum possible score=9) were included for meta-analysis. Pooled risk of sustaining a concussion was more than three times greater in children with a previous concussion compared with those with no previous concussion (RR=3.64; 95% CI: 2.68 to 4.96; p 〈 0.0001; I 2 =90.55%). Unreported sex-stratified data precluded direct comparison of concussion risk in male versus female athletes. Conclusion Previously concussed children have four times the risk of sustaining a concussion compared with those with no previous concussion history. This should be a consideration for clinicians in return to sport decision-making. Future studies examining subsequent recurrent concussion in youth sports must consider sex differences.

Abstract: Recovery from concussion has traditionally been evaluated by patient-reported symptoms, objective measures such as loss of consciousness, specific dimensions such as depression or fatigue, cognitive status, employment status, level of physical activity and the more complex construct of disability. Increasingly, patient-reported outcome measures of health-related quality of life (HRQOL) are being emphasised as an important end point in patient care, clinical trial and health policy decisions. Currently, no standardised concussion-specific HRQOL outcome measure exists. The process for developing a concussion-specific HRQOL outcome measure based on the international classification of functioning, disability and health is outlined. Methods and analysis A multistage, patient-centred approach to developing the outcome measure will integrate evidence from systematic reviews, qualitative research and cognitive interviewing into a self-report questionnaire to guide clinical decision-making. The psychometric properties of the questionnaire will be evaluated to assess the inter-rater reliability and construct validity of the measure in individuals with persistent post-concussion symptoms. To date, the systematic review and the clinical expert interviews within the preparatory phase have been completed and work is progressing on the subsequent phases. It is anticipated that the outcome measure will be ready for psychometric testing in September 2018. Ethics and dissemination Ethical approval was granted by the Ottawa Health Science Network Research Ethics Board (Protocol #20170720-01H) on 31 October 2017 to conduct the patient and clinical expert interviews. Ethical approval for psychometric testing of the outcome measure will be sought by the Ottawa Health Science Network Research Ethics Board in Phase II, after the development of the final HRQOL questionnaire. Results will be disseminated through peer-reviewed journals and professional conferences. PROSPERO registration Phase I systematic review registration number CRD42017075588 (15 June 2017). Phase II systematic review registration number CRD42017075588 (27 September 2017).

Abstract: Headache is the most common symptom after pediatric concussion. Objectives To examine whether posttraumatic headache phenotype is associated with symptom burden and quality of life 3 months after concussion. Design, Setting, and Participants This was a secondary analysis of the Advancing Concussion Assessment in Pediatrics (A-CAP) prospective cohort study, conducted September 2016 to July 2019 at 5 Pediatric Emergency Research Canada (PERC) network emergency departments. Children aged 8.0-16.99 years presenting with acute ( & amp;lt;48 hours) concussion or orthopedic injury (OI) were included. Data were analyzed from April to December 2022. Exposure Posttraumatic headache was classified as migraine or nonmigraine headache, or no headache, using modified International Classification of Headache Disorders, 3rd edition, diagnostic criteria based on self-reported symptoms collected within 10 days of injury. Main Outcomes and Measures Self-reported postconcussion symptoms and quality-of-life were measured at 3 months after concussion using the validated Health and Behavior Inventory (HBI) and Pediatric Quality of Life Inventory–Version 4.0 (PedsQL-4.0). An initial multiple imputation approach was used to minimize potential biases due to missing data. Multivariable linear regression evaluated the association between headache phenotype and outcomes compared with the Predicting and Preventing Postconcussive Problems in Pediatrics (5P) clinical risk score and other covariates and confounders. Reliable change analyses examined clinical significance of findings. Results Of 967 enrolled children, 928 (median [IQR] age, 12.2 [10.5 to 14.3] years; 383 [41.3%] female) were included in analyses. HBI total score (adjusted) was significantly higher for children with migraine than children without headache (estimated mean difference [EMD] , 3.36; 95% CI, 1.13 to 5.60) and children with OI (EMD, 3.10; 95% CI, 0.75 to 6.62), but not children with nonmigraine headache (EMD, 1.93; 95% CI, −0.33 to 4.19). Children with migraine were more likely to report reliable increases in total symptoms (odds ratio [OR], 2.13; 95% CI, 1.02 to 4.45) and somatic symptoms (OR, 2.70; 95% CI, 1.29 to 5.68) than those without headache. PedsQL-4.0 subscale scores were significantly lower for children with migraine than those without headache only for physical functioning (EMD, −4.67; 95% CI, −7.86 to −1.48). Conclusions and Relevance In this cohort study of children with concussion or OI, those with posttraumatic migraine symptoms after concussion had higher symptom burden and lower quality of life 3 months after injury than those with nonmigraine headache. Children without posttraumatic headache reported the lowest symptom burden and highest quality of life, comparable with children with OI. Further research is warranted to determine effective treatment strategies that consider headache phenotype.