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Background: Pre-existing mental health diagnoses may contribute to greater emotional symptom burden and prolonged recovery after concussion.Hypothesis: Youth with pre-existing mental health diagnoses will have greater emotional symptom burden, greater risk for delayed return to exercise, and more prolonged recovery from concussion than those without those diagnoses.Study Design: Prospective cohort.Level of Evidence: Level 3.Methods: A prospective registry of youth concussion was examined for differences in emotional symptom burden after injury to develop a predictive risk model for prolonged recovery. The impact of individual and total number of pre-existing mental health diagnoses (0, 1, 2, and 3+) was assessed, and multivariable logistic regression was performed to identify factors associated with prolonged recovery.Results: Among a cohort of 3105 youth with concussion, those with a history of mental health diagnoses, in a dose-response fashion, had greater postinjury emotional symptom burden (7 emotional symptoms vs 4; P< 0.01), visio-vestibular dysfunction (65% abnormal vs 56% abnormal; P< 0.01), later return to symptom-limited exercise (23 vs 21 days; P< 0.01), and overall longer concussion recovery (38 days, interquartile range [IQR] 18, 80) versus 25 days (IQR 13, 54; P< 0.01). Boys with prolonged recovery after concussion had greater emotional symptom burden than girls (5 emotional symptoms vs 3; P< 0.01).Conclusion: Pre-existing mental health diagnoses are associated with greater postinjury emotional symptom burden and longer concussion recovery in a dose-response fashion. Visiovestibular deficits and delayed return to exercise are also associated with pre-existing mental health diagnoses and prolonged recovery. Boys with prolonged recovery from concussion experience greater emotional symptom burden than girls.Clinical Relevance: Addressing pre-existing mental health diagnoses is essential to concussion management. Boys with prolonged recovery from concussion may particularly benefit from interventions to address their higher emotional symptom burden. Interventions, including a home visio-vestibular exercise program and symptom-limited exercise, may contribute to improving time to concussion recovery.

Background: While concussions are common pediatric injuries, a lack of agreement on a standard definition of recovery creates multiple challenges for clinicians and researchers alike.Hypothesis: The percentage of concussed youth deemed recovered as part of a prospective cohort study will differ depending on the recovery definition.Study Design: Descriptive epidemiologic study of a prospectively enrolled observational cohortLevel of Evidence: Level 3.Methods: Participants aged 11 to 18 years were enrolled from the concussion program of a tertiary care academic center. Data were collected from initial and follow-up clinical visits ≤12 weeks from injury. A total of 10 recovery definitions were assessed: (1) cleared to full return to sports; (2) return to full school; (3) self-reported return to normal; (4) self-reported full return to school; (5) self-reported full return to exercise; (6) symptom return to preinjury state; (7) complete symptom resolution; (8) symptoms below standardized threshold; (9) no abnormal visio-vestibular examination (VVE) elements; and (10) ≤1 abnormal VVE assessments.Results: In total, 174 participants were enrolled. By week 4, 63.8% met at least 1 recovery definition versus 78.2% by week 8 versus 88.5% by week 12. For individual measures of recovery at week 4, percent recovered ranged from 5% by self-reported full return to exercise to 45% for ≤1 VVE abnormality (similar trends at 8 and 12 weeks).Conclusion: There is wide variability in the proportion of youth considered recovered at various points following concussion depending on the definition of recovery, with higher proportions using physiologic examination-based measures and lower proportions using patient-reported measures.Clinical Relevance: These results further emphasize the need for a multimodal assessment of recovery by clinicians as a single and standardized definition of recovery that captures the broad impact of concussion on a given patient continues to be elusive.

Background: Few studies have examined psychiatric symptoms during the acute phase following a concussion in adolescents. Thus, this study compares anxiety and depression in acutely concussed and nonconcussed adolescents.Hypothesis: Acutely concussed adolescents will report greater anxiety and depressive symptoms compared with nonconcussed adolescents.Study Design: Prospective cohort study.Level of Evidence: Level 3.Methods: Data were collected from 282 adolescents (111 concussed within 28 days of injury, 171 nonconcussed), 13 to 18 years of age, who completed Patient-Reported Outcome Measurement Information System (PROMIS) Anxiety and Depressive Symptoms measures. We calculated average T-scores for anxiety and depression across both groups and compared the proportion of those who scored above normal limits. Finally, we calculated risk ratios for anxiety and depression scores above normal limits.Results: Average T-scores for anxiety did not differ in concussed versus nonconcussed adolescents (mean: 45.9 [SD 10.84] vs 45.2 [8.1], respectively, P= 0.54), whereas average T-scores for depression were significantly higher in concussed versus nonconcussed adolescents (46.0 [10.88] vs 42.8 [8.48], respectively, P< 0.01). The proportion of concussed adolescents above normal limits for depression was greater than nonconcussed adolescents (32.4% vs 20.5%, respectively, P= 0.02). Post hoc sensitivity analyses excluding those with a history of anxiety or depression demonstrated a 1.45 (95% CI, 0.97, 2.01) and 1.56 (95% CI, 0.95, 2.56) increased risk of an above-normal anxiety and depression score for concussed compared with nonconcussed adolescents, respectively, although both were nonsignificant.Conclusion: Although we found few significant differences between the 2 groups, the results highlight that many concussed adolescents met the threshold for above-average symptoms on the depression and anxiety PROMIS measures.Clinical Relevance: In adolescents, there is increased risk for psychiatric sequalae in the acute period after a concussion. As such, we suggest that clinicians consider incorporating depression screening when caring for adolescents after a concussion.

Understanding the size and shape variations of the head is important to the design of football helmets used to mitigate the risk of head injury. Current guidelines for selecting helmets use only the circumference of the player’s head to determine an appropriate size that may not offer the best fit and protection for every player. The goal of this study was to quantify key measurements of head shape to sufficiently characterize variability among players in the National Football League (NFL), focusing on the shape variation of the cranial region. Statistical shape analysis was performed on three-dimensional head scans of 87 contemporary NFL players to identify key features of head shape variability among the players’ heads. The principal component analysis revealed two factors that explained 87% of the head shape variance: (1) height and length of the head in the sagittal plane and (2) prominent back of the head with an oval shape in the transverse plane versus prominent forehead with a round shape. Four head shape measurements (circumference, length, breadth, and height) were then defined and quantified to describe the first two principal components. This information can facilitate improvements in the design of football helmets.

ABSTRACTObjectiveTo evaluate pre – to post-season differences in individual subtests of the Visio-Vestibular Examination (VVE) in healthy middle and high school athletes.MethodsThis prospective cohort study recruited participants from a private suburban United States secondary school. Participants completed a demographic questionnaire prior to the start of their season. A proxy for head impact exposure was estimated by incorporating previously published head impact frequencies by team and sport. The VVE was completed pre – and post-season and consisted of 9 subtests: smooth pursuit, horizontal/vertical saccades and gaze stability, binocular convergence, left/right monocular accommodation, and complex tandem gait. Generalized estimating equations were employed to assess the relative risk of an abnormal VVE outcome based on testing session (pre – vs. post-season).ResultsParticipants included middle and high school athletes (n = 115; female = 59 (51.3%); median age at first assessment = 14.9 years, [IQR = 13.6, 16.0]) during 2017/18 – 2019/20 school years. During pre-season testing, accommodation (10.0%) and complex tandem gait (9.2%) had the largest proportion of abnormal outcomes, while smooth pursuits (10.6%) and convergence (9.5%) had the largest proportion of abnormal outcomes post-season. When assessing the effect of testing session on the relative risk of any abnormal VVE subtest, there were no significant findings (P ≥ 0.25). Additionally, there were no significant effects of testing session when adjusting for estimated head impact exposure for any VVE subtest (P ≥ 0.25).ConclusionsVisio-vestibular function as measured by the VVE does not change from pre – to post-season in otherwise healthy adolescent athletes. Our findings suggest that the VVE may be stable and robust to typical neurodevelopment occurring in this dynamic age group and help inform post-injury interpretation of visio-vestibular impairments.

Sport-related concussion is a public health problem, particularly in adolescents. Quality of life is reduced in adolescents with persistent post-concussive symptoms (symptoms >28 days). We replicated a previous randomised controlled trial to validate the safety, efficacy, and generalisability of, and objective adherence to, prescribed early targeted heart rate subsymptom threshold aerobic exercise compared with placebo-like stretching exercise for adolescent recovery from sport-related concussion and for reducing the risk of persistent post-concussive symptoms.

ObjectivesTo examine sex differences in sport-related concussion (SRC) across comparable sports.MethodsProspective cohort of collegiate athletes enrolled between 2014 and 2017 in the Concussion Assessment, Research and Education Consortium study.ResultsAmong 1071 concussions (females=615; 57.4%), there was no difference in recovery (median days to full return to play) (females=13.5 (IQR 9.0, 23.1) vs males=11.8 (IQR 8.1, 19.0), p=0.96). In subgroup analyses, female recovery was longer in contact (females=12.7 days (IQR 8.8, 21.4) vs males=11.0 days (IQR 7.9, 16.2), p=0.0021), while male recovery was longer in limited contact sports (males=16.9 days (IQR 9.7, 101.7) vs females=13.8 days (IQR 9.1, 22.0), p<0.0001). There was no overall difference in recovery among Division I schools (females=13.7 (IQR 9.0, 23.1) vs males=12.2 (IQR 8.2 19.7), p=0.5), but females had longer recovery at the Division II/III levels (females=13.0 (IQR 9.2, 22.7) vs males=10.6 (IQR 8.1, 13.9), p=0.0048).ConclusionOverall, no difference in recovery between sexes across comparable women’s and men’s sports in this collegiate cohort was found. However, females in contact and males in limited contact sports experienced longer recovery times, while females had longer recovery times at the Division II/III level. These disparate outcomes indicate that, while intrinsic biological sex differences in concussion recovery may exist, important, modifiable extrinsic factors may play a role in concussion outcomes.

IMPORTANCE: Concussion diagnosis remains clinical, without objective diagnostic tests available for adolescents. Known deficits in visual accommodation and autonomic function after concussion make the pupillary light reflex (PLR) a promising target as an objective physiological biomarker for concussion. OBJECTIVE: To determine the potential utility of PLR metrics as physiological biomarkers for concussion. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort of adolescent athletes between ages 12 and 18 years recruited between August 1, 2017, and December 31, 2018. The study took place at a specialty concussion program and private suburban high school and included healthy control individuals (n = 134) and athletes with a diagnosis of sport-related concussion (SRC) (n = 98). Analysis was completed June 30, 2020. EXPOSURES: Sports-related concussion and pupillometry assessments. MAIN OUTCOMES AND MEASURES: Pupillary light reflex metrics (maximum and minimum pupillary diameter, peak and average constriction/dilation velocity, percentage constriction, and time to 75% pupillary redilation [T75]). RESULTS: Pupillary light reflex metrics of 134 healthy control individuals and 98 athletes with concussion were obtained a median of 12.0 days following injury (interquartile range [IQR], 5.0-18.0 days). Eight of 9 metrics were significantly greater among athletes with concussion after Bonferroni correction (maximum pupil diameter: 4.83 mm vs 4.01 mm; difference, 0.82; 99.44% CI, 0.53-1.11; minimum pupil diameter: 2.96 mm vs 2.63 mm; difference, 0.33; 99.4% CI, 0.18-0.48; percentage constriction: 38.23% vs 33.66%; difference, 4.57; 99.4% CI, 2.60-6.55; average constriction velocity: 3.08 mm/s vs 2.50 mm/s; difference, 0.58; 99.4% CI, 0.36-0.81; peak constriction velocity: 4.88 mm/s vs 3.91 mm/s; difference, 0.97; 99.4% CI, 0.63-1.31; average dilation velocity, 1.32 mm/s vs 1.22 mm/s; difference, 0.10; 99.4% CI, 0.00-0.20; peak dilation velocity: 1.83 mm/s vs 1.64 mm/s; difference, 0.19; 99.4% CI, 0.07-0.32; and T75: 1.81 seconds vs 1.51 seconds; difference, 0.30; 0.10-0.51). In exploratory analyses, sex-based differences were observed, with girls with concussion exhibiting longer T75 (1.96 seconds vs 1.63 seconds; difference, 0.33; 99.4% CI, 0.02-0.65). Among healthy control individuals, diminished PLR metrics (eg, smaller maximum pupil size 3.81 mm vs 4.22 mm; difference, −0.41; 99.4% CI, −0.77 to 0.05) were observed after exercise. CONCLUSIONS AND RELEVANCE: These findings suggest that enhancement of PLR metrics characterize acute adolescent concussion, while exercise produced smaller pupil sizes and overall slowing of PLR metrics, presumably associated with fatigue. Quantifiable measures of the PLR may serve in the future as objective physiologic biomarkers for concussion in the adolescent athlete.

Objective: To address the predictability of injury from air bag activation by use of crash simulation software. Methods: Using current, validated crash simulation software, the effect of air bag activation on injury risk was assessed for the 6-year-old child, both restrained and unrestrained. Results were compared with those for adult occupants in similar crash scenarios. Results: For the unrestrained child passenger, crash simulations predicted serious head, neck, and chest injuries with air bag activation, regardless of crash severity. For the restrained child passenger, crash simulations predicted similar severe injuries for high-severity crashes only. No serious injuries were predicted for unrestrained male adults exposed to air bags or for child passengers restrained in the rear seat for the crash scenarios simulated. Conclusions: Using current crash simulation software, this study demonstrated that the risk of air bags to school-aged children could be predicted. Our results confirmed the previously identified risks to unrestrained children and provided the first evidence that air bags, in their current design, are not beneficial to restrained children. This study illustrates that computer crash simulations should be used proactively to identify injury risks to child occupants, particularly when limited real-world data are available. Arch Pediatr Adolesc Med. 2000;154:276-280, Researchers report the use of crash simulation software to show that young children in the front seat of a car are at risk of injury from air bag activation in the event of a crash. If children are not restrained by a seat belt system, they would suffer serious head, neck, and chest injuries with air bag activation, even in a minor crash. If they are restrained, they would only suffer severe injuries in a severe crash. Children restrained in the rear seat would not be affected by air bag activation.

ObjectivesThe National Highway Traffic Safety Administration and the American Academy of Pediatrics recommend children be placed in rear-facing child restraint systems (RFCRS) until at least age 2. These recommendations are based on laboratory biomechanical tests and field data analyses. Due to concerns raised by an independent researcher, we re-evaluated the field evidence in favour of RFCRS using the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) database.MethodsChildren aged 0 or 1 year old (0–23 months) riding in either rear-facing or forward-facing child restraint systems (FFCRS) were selected from the NASS-CDS database, and injury rates were compared by seat orientation using survey-weighted χ2tests. In order to compare with previous work, we analysed NASS-CDS years 1988–2003, and then updated the analyses to include all available data using NASS-CDS years 1988–2015.ResultsYears 1988–2015 of NASS-CDS contained 1107 children aged 0 or 1 year old meeting inclusion criteria, with 47 of these children sustaining injuries with Injury Severity Score of at least 9. Both 0-year-old and 1-year-old children in RFCRS had lower rates of injury than children in FFCRS, but the available sample size was too small for reasonable statistical power or to allow meaningful regression controlling for covariates.ConclusionsNon-US field data and laboratory tests support the recommendation that children be kept in RFCRS for as long as possible, but the US NASS-CDS field data are too limited to serve as a strong statistical basis for these recommendations.

The current study aimed to quantify the real-world, everyday travel behaviours of child vehicle occupants and associations with child restraint systems (CRS)/booster seat (BS) head positions that are suboptimal in terms of crash injury risk.

The performance of child restraint systems (CRS) in side impact motor vehicle crashes has been under study due to the injury and fatality burden of these events. Although previous research has quantified injury risk or described injured body regions, safety advances require an understanding of injury causation. Therefore, the objective was to delineate injury causation scenarios for CRS-restrained children in side impacts and document probable contact points in the vehicle interior.

Passenger compartment intrusion, loss of integrity of the vehicle occupant compartment due to a motor vehicle crash, has frequently been used as a triage criterion. Data to support intrusion as a proxy for injury severity in child occupants are lacking. The purpose of this study was to examine the association between intrusion and injury to children in motor vehicle crashes.

Previous research has identified key predictors of elevated abdominal injury risk in seat belt-restrained child vehicle occupants; however these data cannot be used to isolate specific mechanisms or sources of injury to suggest strategies for prevention.

Characteristic patterns of injury to children in automobile crashes resulting from lap and lap-shoulder belts have been described for many years. These injuries are known as the “seat belt syndrome.” We present a typical case of seat belt syndrome involving a 4-year-old boy and review the current literature on the topic, highlighting proposed mechanisms of intra-abdominal and spine injuries. In addition, recent research findings identifying a new pattern of injuries associated with inappropriate seat belt use in young children are reviewed. Emergency physicians must consider these seat belt-related injuries in the initial evaluation of any child involved in a motor vehicle crash who was restrained with the vehicle seat belt.

Clinical and biomechanical investigations indicate that assessment of vertebral body bone mineral density (BMD) by anteroposterior dual‐energy x‐ray absorptiometry (DXA) is a useful index of vertebral body strength and fracture risk in osteoporosis. However, inclusion of non‐force‐bearing and small‐force‐bearing mineralized structures, such as the posterior elements and aortic calcifications, in the measurement of anterior BMD obscures the assessment of vertebral body mass by this technique. Indeed, such interference is particularly severe in the presence of posterior element degeneration or previous spinal surgery. Recent anatomic studies illustrate that the lateral view provides unobstructed visualization of the L3, L4, and possibly L2 vertebral bodies, suggesting that supine lateral BMD may more accurately assess vertebral body fracture risk. We evaluated this hypothesis in a blinded study using human cadaver spines to compare the value of supine lateral and anteroposterior BMD in assessing vertebral body fracture force, average compressive stress, maximum stored strain energy, and strain at failure. Both measures of BMD significantly correlate with these biomechanical measures. However, statistical comparison of the methods using multiple and stepwise regression reveals that supine lateral BMD provides a better assessment of the vertebral body fracture properties than anteroposterior BMD. The enhanced predictive value of supine lateral BMD occurs because of the variable contribution of posterior element mineral to the anteroposterior BMD measurement. Evaluation to test the utility of supine lateral BMD for the assessment of fracture risk and a fracture threshold in patients with osteoporosis is therefore recommended.

Recent advances in technology have enabled the development of instrumented equipment, which estimate the head impact kinematics of athletes in vivo. One such headband-mounted impact sensor is the SIM-G (Triax Technologies, Norwalk, CT, USA), which has been previously used to investigate the biomechanics of soccer heading by human subjects. Previous studies have evaluated the accuracy of the SIM-G for pure rotation and pendulum, impulse hammer and drop rig impacts. The current study used a soccer ball heading model to evaluate the accuracy of the SIM-G. A soccer ball was projected at the head of an anthropomorphic test device (ATD) representing a 10-year-old to replicate the heading maneuver at various impact sites, angles and speeds previously identified in youth soccer. Linear regression revealed that the SIM-G sensor overestimated the peak angular velocity and linear acceleration recorded by the ATD headform by approximately 44% and 105%, respectively. Tests in which the ball directly contacted the SIM-G sensor resulted in the largest peak linear accelerations. Glancing impacts were significantly associated with a decrease in percentage error of the SIM-G sensor peak angular velocity data relative to the ATD reference data. While it may not demonstrate accuracy in estimating the magnitudes of head impacts, the SIM-G remains a useful tool to provide estimates of head impact exposure for soccer players.

ObjectiveTo compare linear and rotational acceleration across age and gender in controlled purposeful soccer heading.DesignProspective study.SettingBiomechanics laboratory.ParticipantsOne-hundred soccer players (42 male, 58 female, 17.1±3.5 years, 168.5±20.3 cm, 61.5±13.7 kg) classified as collegiate, high school (HS), or youth (12–14 years) male (MS) or female (FS) soccer players.Exclusionary criteriahistory of neurologic disorder, cervical spine injury, or head injury in the past 6 months.InterventionsWe implemented a unique soccer heading paradigm that allows for precise control of head impact magnitude, direction, and frequency to model repetitive head impacts in sport. This model consists of controlled soccer heading (12 headers at 11.2 m/s from a JUGS machine) while measuring linear and rotational accelerations using a triaxial accelerometer and gyroscope affixed to the back of the head. Linear accelerations were transformed to the head center-of-gravity using 3D motion capture data and standard rigid body dynamics equations.Outcome measuresLinear and rotational accelerations at the head center-of-gravity.Main results[Average±Standard Deviation (95% Confidence Interval)] Collegiate [42.4±11.5 g (36.8–47.9); 3.35±0.87 krad/s2(2.9–3.8)], HS [38.5±13.1 g (32.2–44.8); 3.16±1.01 krad/s2(2.7–3.7)], and youth [40.5±14.9 g(33.1–47.9); 3.20±1.24 krad/s2(2.6–3.8)] FS produced higher linear and rotational accelerations than both the collegiate [26.1±9.5 g(21.7–30.6); 2.13±1.07 krad/s2(1.6–2.6)] (linear: p<0.001, p?= 0.012, p=0.002; rotational: p=0.002, p=0.015, p=0.011, respectively) and HS [26.7±5.9 g(23.2–30.1); 2.18±0.40 krad/s2(2.0–2.4)] (linear: p=0.002, p=0.045, p?= 0.012; rotational: p=0.011, p=0.052, p=0.040, respectively) MS.ConclusionsCollegiate and HS FS have higher head accelerations than their male counterparts, but at the youth level, there are no differences across gender. These data suggest that FS may be exposed to greater cumulative head accelerations from repeated heading of a soccer ball over a career than MS.Competing interestsNone.

ObjectiveVestibular and oculomotor visual (VOM) deficits are emerging as key characteristics of youth concussion. However, since most studies of paediatric concussion focus on adolescents, little is known about the extent to which younger children experience this deficit. To address this gap, we used an electronic health record (EHR) system across a large paediatric healthcare network to quantify the presence of VOM deficits following concussion in patients under age 12.DesignDescriptive epidemiology.SettingData were collected from all primary (n=31) and relevant specialty care (n=4) network settings.ParticipantsWe identified all patients aged 5–11 years who had ≥1 clinical visit for concussion at a network primary or specialty care site from 7/1/2014 through 6/30/2015. We included the 82% of these patients for whom a concussion electronic clinical decision support tool within the EHR was used during their initial visit.Outcome measuresThe proportion who demonstrated each VOM deficit – balance, saccades, gaze stability, and convergence – was calculated among all who were assessed for that deficit.Main results871 patients were included (median [IQR]: 10 [8, 11] years). On physical examination, 58% had at least one VOM deficit. 44% had balance abnormalities, 39% had saccadic dysfunction, 28% had deficits in gaze stability, and 10% convergence insufficiency.ConclusionsIn this sample, vestibular oculomotor visual deficits following concussion in young children were common. Improved recognition of the deficits will lead to timely diagnosis and appropriate management, including school accommodations for oculomotor visual challenges and vestibular therapy for motion sensitivity issues.Competing interestsNone.KB, Arbogast serves as a consultant to the National Football League Players Association on head injury topics.

ObjectiveTo identify factors that contribute to head acceleration during purposeful soccer heading.DesignProspective.SettingBiomechanics laboratory.ParticipantsOne-hundred soccer players (42 male, 58 female, 17.1±3.5 years (range: 12-24years), 168.5±20.3 cm, 61.5±13.7 kg). Exclusionary criteria: history of neurologic disorder, cervical spine injury, or head injury in the past 6 months.InterventionsWe implemented a soccer heading paradigm that consists of controlled soccer heading (12 headers at 11.2m/s from a JUGS machine) while measuring 3D motion capture kinematics (torso and head-to-torso range-of-motion), sternocleidomastoid and upper trapezius EMG activity (peak and area), and linear and rotational accelerations using a triaxial accelerometer and gyroscope. Head mass, neck girth, and sternocleidomastoid and upper trapezius strength were also evaluated.Outcome measuresLinear and rotational accelerations at the head center-of-gravity.Main resultsMultiple regression analyses suggest that the ten variables predicted linear (R2=0.272, p=0.002) and rotational (R2=0.259, p=0.004) acceleration; however none of the predictors individually made a significant contribution to the model. Linear and rotational accelerations were correlated with head mass (r=-?0.447, p<0.001; r=-0.467,p<0.001), neck girth (r=-0.465, p<0.001; r=-0.438, p<0.001), sternocleidomastoid strength (r=-0.386, p<0.001; r=-0.410, p<0.001), and upper trapezius strength (r=-0.311, p=0.001; r=-0.351, p<0.001).ConclusionsOur findings suggest that head mass, neck girth, and neck strength are important in minimising head acceleration, whereby greater size and strength are associated with lower head accelerations. Soccer players with smaller head-neck segment masses and lower neck strength, may be at risk for greater head acceleration. These athletes may experience a theoretical bobble-head effect, when the neck strength is not great enough to control the mass of the head.Competing interestsNone.

IMPORTANCE: Previous epidemiologic research on concussions has primarily been limited to patient populations presenting to sport concussion clinics or to emergency departments (EDs) and to those high school age or older. By examining concussion visits across an entire pediatric health care network, a better estimate of the scope of the problem can be obtained. OBJECTIVE: To comprehensively describe point of entry for children with concussion, overall and by relevant factors including age, sex, race/ethnicity, and payor, to quantify where children initially seek care for this injury. DESIGN, SETTING, AND PARTICIPANTS: In this descriptive epidemiologic study, data were collected from primary care, specialty care, ED, urgent care, and inpatient settings. The initial concussion-related visit was selected and variation in the initial health care location (primary care, specialty care, ED, or hospital) was examined in relation to relevant variables. All patients aged 0 to 17 years who received their primary care from The Children’s Hospital of Philadelphia’s (CHOP) network and had 1 or more in-person clinical visits for concussion in the CHOP unified electronic health record (EHR) system (July 1, 2010, to June 30, 2014) were selected. MAIN OUTCOMES AND MEASURES: Frequency of initial concussion visits at each type of health care location. Concussion visits in the EHR were defined based on International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes indicative of concussion. RESULTS: A total of 8083 patients were included (median age, 13 years; interquartile range, 10-15 years). Overall, 81.9% (95% CI, 81.1%-82.8%; n = 6624) had their first visit at CHOP within primary care, 5.2% (95% CI, 4.7%-5.7%; n = 418) within specialty care, and 11.7% (95% CI, 11.0%-12.4%; n = 947) within the ED. Health care entry varied by age: 52% (191/368) of children aged 0 to 4 years entered CHOP via the ED, whereas more than three-quarters of those aged 5 to 17 years entered via primary care (5-11 years: 1995/2492; 12-14 years: 2415/2820; and 15-17 years: 2056/2403). Insurance status also influenced the pattern of health care use, with more Medicaid patients using the ED for concussion care (478/1290 Medicaid patients [37%] used the ED vs 435/6652 private patients [7%] and 34/141 self-pay patients [24%]). CONCLUSIONS AND RELEVANCE: The findings suggest estimates of concussion incidence based solely on ED visits underestimate the burden of injury, highlight the importance of the primary care setting in concussion care management, and demonstrate the potential for EHR systems to advance research in this area.