Melissa A. Fraser

Head impact locations in US high school boys’ and girls’ soccer concussions, 2012/13-2015/16

This study describes concussions and concussion-related outcomes sustained by high school soccer players by head impact location, sex, and injury mechanism. Data were obtained for the 2012/13-2015/16 school years from the National High School Sports-Related Injury Surveillance System, High School RIO™. This Internet-based sports injury surveillance system captures data reported by athletic trainers from an annual average of 162 U.S. high schools. Data were analyzed to describe circumstances of soccer concussion (e.g., symptomology, symptom resolution, and return-to-play time) by impact location (i.e., front- [face included], back-, side-, and top-of-the-head) and sex. Most concussions were from front-of-the-head impacts (boys, 30.5%; girls, 34.0%). Overall, 4.1 ± 2.2 and 4.6 ± 2.3 symptoms were reported in boys and girls, respectively. In boys, symptom frequency was not associated with head impact location (p = 0.66); an association was found in girls (p = 0.02), with the highest symptom frequency reported in top-of-the-head impacts (5.4 ± 2.2). Head impact location was not associated with symptom resolution time (boys, p = 0.21; girls, p = 0.19) or return-to-play time (boys, p = 0.18; girls, p = 0.07). Heading was associated with 28.0% and 26.5% of concussions in boys and girls, respectively. Most player-player contact concussions during heading occurred from side-of-the-head impacts (boys, 49.4%; girls, 43.2%); most heading-related ball contact concussions occurred from front-of-the-head (boys, 41.4%; girls, 42.6%) and top-of-the-head (boys, 34.5%; girls, 36.9%) impacts. Head impact location was generally independent of symptom resolution time, return-to-play time, and recurrence among high school soccer concussions. However, impact location may be associated with reported symptom frequency. Further, many of these clinical concussion descriptors were associated with sex.

Ball-Contact Injuries in 11 National Collegiate Athletic Association Sports: The Injury Surveillance Program, 2009–2010 Through 2014–2015

CONTEXT   Surveillance data regarding injuries caused by ball contact in collegiate athletes have not been well examined and are mostly limited to discussions of concussions and catastrophic injuries. OBJECTIVE   To describe the epidemiology of ball-contact injuries in 11 National Collegiate Athletic Association (NCAA) sports during the 2009-2010 through 2014-2015 academic years. DESIGN   Descriptive epidemiology study. SETTING   Convenience sample of NCAA programs in 11 sports (mens football, womens field hockey, womens volleyball, mens baseball, womens softball, mens and womens basketball, mens and womens lacrosse, and mens and womens soccer) during the 2009-2010 through 2014-2015 academic years. PATIENTS OR OTHER PARTICIPANTS   Collegiate student-athletes participating in 11 sports. MAIN OUTCOME MEASURE(S)   Ball-contact-injury rates, proportions, rate ratios, and proportion ratios with 95% confidence intervals were based on data from the NCAA Injury Surveillance Program during the 2009-2010 through 2014-2015 academic years. RESULTS   During the 2009-2010 through 2014-2015 academic years, 1123 ball-contact injuries were reported, for an overall rate of 3.54/10 000 AEs. The sports with the highest rates were womens softball (8.82/10 000 AEs), womens field hockey (7.71/10 000 AEs), and mens baseball (7.20/10 000 AEs). Most ball-contact injuries were to the hand/wrist (32.7%) and head/face (27.0%) and were diagnosed as contusions (30.5%), sprains (23.1%), and concussions (16.1%). Among sex-comparable sports (ie, baseball/softball, basketball, and soccer), women had a larger proportion of ball-contact injuries diagnosed as concussions than men (injury proportion ratio = 2.33; 95% confidence interval = 1.63, 3.33). More than half (51.0%) of ball-contact injuries were non-time loss (ie, participation-restriction time <24 hours), and 6.6% were severe (ie, participation-restriction time ≥21 days). The most common severe ball-contact injuries were concussions (n = 18) and finger fractures (n = 10). CONCLUSION   Ball-contact-injury rates were the highest in womens softball, womens field hockey, and mens baseball. Although more than half were non-time-loss injuries, severe injuries such as concussions and fractures were reported.

White Matter Changes Related to Subconcussive Impact Frequency during a Single Season of High School Football

Seventeen male athletes (mean age, 16 years) underwent MR imaging before and after the football season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis. The mean number of impacts over a 10-g threshold sustained was 414. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The authors conclude that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level. BACKGROUND AND PURPOSE: The effect of exposing the developing brain of a high school football player to subconcussive impacts during a single season is unknown. The purpose of this pilot study was to use diffusion tensor imaging to assess white matter changes during a single high school football season, and to correlate these changes with impacts measured by helmet accelerometer data and neurocognitive test scores collected during the same period. MATERIALS AND METHODS: Seventeen male athletes (mean age, 16 ± 0.73 years) underwent MR imaging before and after the season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis. RESULTS: The mean number of impacts over a 10-g threshold sustained was 414 ± 291. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant (P < .05, corrected) decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The effects were strongest in the fornix-stria terminalis, where decreases in fractional anisotropy correlated with worsening visual memory. CONCLUSIONS: Our findings suggest that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level.

Football Equipment Removal Improves Chest Compression and Ventilation Efficacy

Abstract Objective: Airway access recommendations in potential catastrophic spine injury scenarios advocate for facemask removal, while keeping the helmet and shoulder pads in place for ensuing emergency transport. The anecdotal evidence to support these recommendations assumes that maintaining the helmet and shoulder pads assists inline cervical stabilization and that facial access guarantees adequate airway access. Our objective was to determine the effect of football equipment interference on performing chest compressions and delivering adequate ventilations on patient simulators. We hypothesized that conditions with more football equipment would decrease chest compression and ventilation efficacy. Methods: Thirty-two certified athletic trainers were block randomized to participate in six different compression conditions and six different ventilation conditions using human patient simulators. Data for chest compression (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of adequate compressions) and ventilation (total ventilations, mean ventilation volume, and percentage of ventilations delivering adequate volume) conditions were analyzed across all conditions. Results: The fully equipped athlete resulted in the lowest mean compression depth (F5,154 = 22.82; P < 0.001; Effect Size = 0.98) and delivery of adequate compressions (F5,154 = 15.06; P < 0.001; Effect Size = 1.09) compared to all other conditions. Bag-valve mask conditions resulted in delivery of significantly higher mean ventilation volumes compared to all 1- or 2-person pocketmask conditions (F5,150 = 40.05; P < 0.001; Effect Size = 1.47). Two-responder ventilation scenarios resulted in delivery of a greater number of total ventilations (F5,153 = 3.99; P = 0.002; Effect Size = 0.26) and percentage of adequate ventilations (F5,150 = 5.44; P < 0.001; Effect Size = 0.89) compared to one-responder scenarios. Non-chinstrap conditions permitted greater ventilation volumes (F3,28 = 35.17; P < 0.001; Effect Size = 1.78) and a greater percentage of adequate volume (F3,28 = 4.85; P = 0.008; Effect Size = 1.12) compared to conditions with the chinstrap buckled or with the chinstrap in place but not buckled. Conclusions: Chest compression and ventilation delivery are compromised in equipment-intense conditions when compared to conditions whereby equipment was mostly or entirely removed. Emergency medical personnel should remove the helmet and shoulder pads from all football athletes who require cardiopulmonary resuscitation, while maintaining appropriate cervical spine stabilization when injury is suspected. Further research is needed to confirm our findings supporting full equipment removal for chest compression and ventilation delivery.

Microstructural alterations of cortical and deep gray matter over a season of high school football revealed by diffusion kurtosis imaging

OBJECTIVES To probe microstructural changes that are associated with subconcussive head impact exposure in deep and cortical gray matter of high school football players over a single season. METHODS Players underwent diffusion kurtosis imaging (DKI) and quantitative susceptibility mapping (QSM) scans. Head impact data was recorded. Association between parametric changes and frequency of frontal head impact was assessed. RESULTS In deep gray matter, significant decreases in mean kurtosis (MK) and increases in mean diffusivity (MD) over the season were observed in the thalamus and putamen. Correlations between changes in DKI metrics and frequency of frontal impacts were observed in the putamen and caudate. In cortical gray matter, decreases in MK were observed in regions including the pars triangularis and inferior parietal. In addition, increases in MD were observed in the rostral middle frontal cortices. Negative correlations between MK and frequency of frontal impacts were observed in the posterior part of the brain including the pericalcarine, lingual and middle temporal cortices. Magnetic susceptibility values exhibited no significant difference or correlation, suggesting these diffusion changes common within the group may not be associated with iron-related mechanisms. CONCLUSION Microstructural alterations over the season and correlations with head impacts were captured by DKI metrics, which suggested that DKI imaging of gray matter may yield valuable biomarkers for evaluating brain injuries associated with subconcussive head impact. Findings of associations between frontal impacts and changes in posterior cortical gray matter also indicated that contrecoup injury rather than coup injury might be the dominant mechanism underlying the observed microstructural alterations. ADVANCES IN KNOWLEDGE Significant microstructural changes, as reflected by DKI metrics, in cortical gray matter such as the rostral middle frontal cortices, and in deep gray matter such as the thalamus were observed in high school football players over the course of a single season without clinically diagnosed concussion. QSM showed no evidence of iron-related changes in the observed subconcussive brain injuries. The detected microstructural changes in cortical and deep gray matter correlated with frequency of subconcussive head impacts. IMPLICATIONS FOR PATIENT CARE DKI may yield valuable biomarkers for evaluating the severity of brain injuries associated with subconcussive head impacts in contact sport athletes.

Innovative behaviourbehavior modification strategies to reduce concussion risk in high school american football athletes

Objective To improve tackling and blocking techniques to reduce concussion in high school American football players, and to evaluate the program’s feasibility and acceptance. Design Clustered quasi-experimental study. Setting High schools. Participants Varsity American high school football players on three teams (two intervention; one control). Interventions All players wore in-helmet head impact accelerometers. “High-risk” intervention team players were selected and attended clinician-coach-player mentoring sessions designed to change playing technique. Accelerometer data were used for “high-risk” selection and during mentoring sessions to reinforce the technique-driven intervention. Outcome measures The change in top-of-head impacts and impacts with peak linear acceleration>60 g was compared between intervention and control subjects using linear risk models. Coaches and players completed post-season exit surveys. Main results Ninety-seven players (70 intervention; 27 control) participated. Thirteen (19%) intervention players were identified as “high risk” and received mentoring. The mentored players’ high magnitude impacts (percent>60 g) in practices dropped 1.9 percent from pre-intervention to post-intervention. There was no change in non-mentored players. In post-season surveys, mentored players “strongly agreed” (56%) or “agreed” (44%) that the study improved their playing behaviours. Among intervention team coaches, three (43%) thought the study was “very effective” in changing football player behaviours about safe play, and the remaining four (57%) thought it was “effective.” Conclusions There is growing concern head impact frequency and severity may result in neurological issues for some athletes later in life. If head impact frequency and severity can be reduced through behavioural intervention, this can have a great public health impact. Competing interests This study is funded by a grant from the National Centre for Injury Prevention and Control (Grant #R49CE002479).