The relationship between resilience and neurophysiological stress in Special Operations Forces combat service members.

Military resilience research is increasing due to the growing literature associating resilience with stress adaptation. This study aimed to investigate which physiological stress adaptation components were associated with resilience in Special Operations Forces combat service members. Special Operations Forces combat service members (n = 117) self-reported resilience (ER89) and lifetime clinician-confirmed mild traumatic brain injury history. Participants also underwent transcranial Doppler ultrasonography to measure middle cerebral artery velocity during rest and a breath-holding task. Neither resilience nor mild traumatic brain injury history was significantly associated with middle cerebral artery velocity percent increase following breath-holding; younger Special Operations Forces combat service members had a higher percent increase in middle cerebral artery velocity following a breath-holding task. Resilience was negatively associated with time to return to baseline middle cerebral artery velocity following peak velocity; whereas, mild traumatic brain injury history did not have a significant association. The Special Operations Forces combat service members that scored higher in resilience tended to return to baseline middle cerebral artery velocity following peak velocity faster than their less resilient counterparts. More resilient Special Operations Forces combat service members recovered faster from physiological stress (breath-holding) than less resilient counterparts. This is the first study to investigate resilience and cerebrovascular stress response and recovery in this population. Our initial findings indicated that the Ego Resiliency Scale may be an optimal resilience psychometric and should be used to evaluate effective military resilience trainings, which aim to improve performance and mental health.

The Effect of Sex, Sport, and Preexisting Histories on Baseline Concussion Test Performance in College Lacrosse and Soccer Athletes.

OBJECTIVE: To study sex and sport differences in baseline clinical concussion assessments. A secondary purpose was to determine if these same assessments are affected by self-reported histories of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine. DESIGN: Prospective cohort. SETTING: National Collegiate Athletic Association D1 Universities. PARTICIPANTS: Male and female soccer and lacrosse athletes (n = 237; age = 19.8 ± 1.3 years). ASSESSMENT OF RISK FACTORS: Sport, sex, history of (1) concussion; (2) learning disability; (3) anxiety and/or depression; and (4) migraine. MAIN OUTCOME MEASURES: Sport Concussion Assessment Tool 22-item symptom checklist, Standardized Assessment of Concussion, Balance Error Scoring System (BESS), Generalized Anxiety Disorder 7-item scale, and Patient Health Questionnaire. RESULTS: Female athletes had significantly higher total symptoms endorsed (P = 0.02), total symptom severity (P < 0.001), and BESS total errors (P = 0.01) than male athletes. No other sex, sport, or sex-by-sport interactions were observed (P > 0.05). Previous concussion and migraine history were related to greater total symptoms endorsed (concussion: P = 0.03; migraine: P = 0.01) and total symptom severity (concussion: P = 0.04; migraine: P = 0.02). Athletes with a migraine history also self-reported higher anxiety (P = 0.004) and depression (P = 0.01) scores. No other associations between preexisting histories and clinical concussion outcomes were observed (P > 0.05). CONCLUSIONS: Our findings reinforce the need to individualize concussion assessment and management. This is highlighted by the findings involving sex differences and preexisting concussion and migraine histories. CLINICAL RELEVANCE: Clinicians should fully inventory athletes' personal and medical histories to better understand variability in measures, which may be used to inform return-to-participation decisions following injury.

Patterns and predictors of concussion symptom presentations in NCAA athletes.

Sport-related concussion (SRC) is a complex injury, and SRCs are notably prevalent among National Collegiate Athletic Association (NCAA) athletes. We analysed SRCs and associated exposure data collected within the NCAA Injury Surveillance Program during 2014-2019. A total of 1,709 SRCs were reported with complete symptom profiles during the study period (Women's sports n = 499; Men's sports n = 1,210). Event type and academic class year most commonly predicted specific symptom presentations among athletes in men's sports, while symptom presentation among athletes in women's sports was most commonly predicted by class year and sport classification. We observed 78 and 69 significant pairwise symptom dependencies in men's and women's sports athletes, respectively; odds of longer symptom resolution time were higher with greater counts of symptoms with strongest cross-domain associations. Our findings highlight several contextual predictors of specific symptom presentations and identify parsimonious symptom subsets that may indicate protracted recovery among men's and women's sports athletes.

Association between Sensation-Seeking Behaviors and Concussion-Related Knowledge, Attitudes, Perceived Norms, and Care-Seeking Behaviors among Collegiate Student-Athletes.

There are limited data connecting personality and behavioral tendencies and traits related to concussion care-seeking/disclosure behaviors and minimal research exists surrounding the relationship between risky behaviors, sensation-seeking, and concussion-related outcomes. This study examined the association between sensation-seeking and a student-athlete's concussion-related knowledge, attitudes, perceived social norms, and concussion care-seeking/disclosure behaviors (intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury). The current study utilized a retrospective cohort of collegiate student-athletes at a single National Collegiate Athletic Association Division I institution. Separate multivariable linear regression models estimating mean differences (MD) and 95% Confidence Intervals (CI) estimated the association between sensation-seeking and concussion knowledge, concussion attitudes, and perceived social norms. Separate multivariable binomial regression models estimating adjusted prevalence ratios (PR) and 95%CI estimated the association between sensation-seeking and intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury. All models were adjusted for sex, sport participation, and concussion history. Higher sensation-seeking was significantly associated with less favorable concussion attitudes (adjusted MD = -1.93; 95%CI = -3.04,-0.83), less favorable perceived social norms surrounding concussion (adjusted MD = -1.39; 95%CI = -2.06,-0.72), and continuing to play while experiencing concussion symptoms (adjusted PR = 1.50; 95%CI = 1.10, 2.06). Student-athletes with increased sensation-seeking could be at risk for failing to disclose a concussion, decreasing athlete safety and resulting in less optimal care post-injury. Results will inform future theory-based concussion education programs which consider behavioral tendencies and traits as well as sport culture to promote concussion care-seeking/disclosure and individualized interventions based on risky behavior engagement.

Progressive Visual Occlusion and Postural Control Responses in Individuals With and Without Chronic Ankle Instability.

CONTEXT: Prophylactic and rehabilitative balance training is needed to maximize postural control and develop appropriate sensory organization strategies. Partially occluding vision during functional exercise may promote appropriate sensory organization strategies, but little is known about the influence of partially occluded vision on postural control in those with and without a history of musculoskeletal injury. OBJECTIVE: To determine the effect of increasing levels of visual occlusion on postural control in a heterogeneous sample of those with and without chronic ankle instability (CAI). The secondary objective was to explore postural control responses to increasing levels of visual occlusion among those with unilateral and bilateral CAI relative to uninjured controls. DESIGN: Cross-sectional. SETTING: Sports medicine research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-five participants with unilateral CAI, 10 with bilateral CAI, and 16 participants with no history of lower extremity injury. MAIN OUTCOME MEASURES: All participants completed four 3-minute postural control assessments in double-limb stance under the following 4 visual conditions: (1) eyes open, (2) low occlusion, (3) high occlusion, and (4) eyes closed. Low- and high-occlusion conditions were produced using stroboscopic eyewear. Postural control outcomes included time-to-boundary minima means in the anteroposterior (TTB-AP) and mediolateral directions (TTB-ML). Repeated-measures analysis of variances tested the effects of visual condition on TTB-AP and TTB-ML. RESULTS: Postural control under the eyes-open condition was significantly better (ie, higher) than the limited visual occlusion and eyes-closed conditions (P < .001) for TTB-AP and TTB-ML. For TTB-AP only, partially occluded vision resulted in better postural control than the eyes-closed condition (P ≤ .003). CONCLUSIONS: Partial and complete visual occlusion impaired postural control during dual-limb stance in a heterogeneous sample of those with and without CAI. Stroboscopic eyewear appears to induce postural control impairments to the same extent as complete visual occlusion in the mediolateral direction.

Neuroinflammatory Biomarkers Associated With Mild Traumatic Brain Injury History in Special Operations Forces Combat Soldiers.

BACKGROUND: Special Operations Forces (SOF) combat soldiers are frequently exposed to blast and blunt neurotrauma, most often classified as mild traumatic brain injury (mTBI). Repetitive mTBI may increase the risk of developing long-term neurological sequelae. Identifying changes in neuroinflammatory biomarkers before chronic conditions emerge could serve as preliminary evidence of developing neuropathology. OBJECTIVE: To determine the effects of mTBI history, lifetime mTBI incidence, and recency on blood biomarker concentrations of axonal protein neurofilament light (NfL), glycolytic enzyme neuron-specific enolase (NSE), astrocyte-expressed S100 calcium-binding protein B (S100B), and neurotrophic cytokine interleukin-6 (IL-6) in healthy, active duty SOF combat soldiers. METHODS: Self-reported mTBI history/recency and fasted blood samples were collected in this cross-sectional study of 104 asymptomatic SOF combat soldiers. Biomarker concentrations were quantified using commercial enzyme-linked immunosorbent assays. Mann-Whitney U and Kruskal-Wallis tests were used to compare groups. Post hoc tests with appropriate corrections were conducted as warranted. RESULTS: Soldiers with mTBI history had higher NSE concentrations than those without (z = -2.60, P = .01). We also observed significant main effects of lifetime mTBI incidence on NSE (χ(3) = 9.52, P = .02) and S100B (χ(3) = 8.21, P = .04) concentrations and a significant main effect of mTBI recency on NfL concentration (χ(2) = 6.02, P = .049). CONCLUSION: The SOF combat soldiers with mTBI history had increased NSE. Longitudinal studies in this population are needed due to between-subject heterogeneity in biomarker concentrations. The NfL concentrations in our SOF combat soldiers-regardless of mTBI history or recency-were similar to values previously reported in civilian acute TBI patients.

Consensus Recommendations on the Prehospital Care of the Injured Athlete With a Suspected Catastrophic Cervical Spine Injury.

INTRODUCTION: Sports participation is among the leading causes of catastrophic cervical spine injury (CSI) in the United States. Appropriate prehospital care for athletes with suspected CSIs should be available at all levels of sport. The goal of this project was to develop a set of best-practice recommendations appropriate for athletic trainers, emergency responders, sports medicine and emergency physicians, and others engaged in caring for athletes with suspected CSIs. METHODS: A consensus-driven approach (RAND/UCLA method) in combination with a systematic review of the available literature was used to identify key research questions and develop conclusions and recommendations on the prehospital care of the spine-injured athlete. A diverse panel of experts, including members of the National Athletic Trainers' Association, the National Collegiate Athletic Association, and the Sports Institute at UW Medicine participated in 4 Delphi rounds and a 2-day nominal group technique (NGT) meeting. The systematic review involved 2 independent reviewers and 4 rounds of blinded review. RESULTS: The Delphi process identified 8 key questions to be answered by the systematic review. The systematic review comprised 1544 studies, 49 of which were included in the final full-text review. Using the results of the systematic review as a shared evidence base, the NGT meeting created and refined conclusions and recommendations until consensus was achieved. CONCLUSIONS: These conclusions and recommendations represent a pragmatic approach, balancing expert experiences and the available scientific evidence.

Sports Medicine Fellowship Training Improves Sport-related Concussion Evaluation.

Evaluating acute sport-related concussion (SRC) differs among providers, who apply international consensus and national guidelines variably. Retrospective medical record review was completed for 889 outpatients aged 7 to 18 years, diagnosed with SRC from 2014 to 2017. Associations between board-certified sports medicine fellowship (SMF) training status and assessment of concussion-specific history and physical examination items were tested using nonparametric χ tests. Differential odds (by fellowship training status) of using history and physical examination items were assessed using multivariable logistic regression modeling. Each SRC history and physical examination items were assessed in higher proportions by SMFs, as compared with non-SMFs, statistically significant for all tested items with the exception of headache history. SMFs demonstrated higher odds of detailed neurologic examinations and clinical cognitive testing compared with non-SMFs, after adjusting for patient and physician characteristics. Physicians caring for concussed patients should seek continuing education opportunities aligning them with training provided to sports medicine fellows.

Effects of College Athlete Life Stressors on Baseline Concussion Measures.

CONTEXT: Concussion baseline testing helps injury evaluation by allowing postinjury comparisons to preinjury measures. To facilitate best practice, common neurocognitive, balance, and symptom report metrics used in concussion baseline testing merit examination relative to participant life stressors. OBJECTIVE: The purpose of this study was to determine if life stressors are associated with college athlete neurocognitive function, postural control, and symptom scores at preseason baseline assessment. DESIGN: All study variables were collected in a single laboratory session where athletes completed valid and reliable psychometrics as well as a computerized neurocognitive and balance assessments. SETTING: Sports medicine research center on an American university campus. PARTICIPANTS: A convenience sample of 123 college student-athletes: 47 females (age = 18.9 [4.3] y) and 76 males (age = 19.4 [1.6] y). MAIN OUTCOME MEASURES: Participants were categorized into low, moderate, or high life stressors groups using scores from the Social Readjustment Rating Scale-Revised. Dependent variables included outcomes from the CNS Vitals Signs test, the Sensory Organization Test, and the graded symptom checklist indexing neurocognition, balance, and symptom severity, respectfully. RESULTS: One-way analysis of variance revealed that the moderate life stressors group performed significantly worse than the low life stressors group on the baseline verbal memory domain of the CNS Vital Signs (F2,119 = 3.28; P = .04) only. CONCLUSION: In the current college athlete sample, few baseline concussion assessment variables were found to be significantly associated with life stressors. Considering the clinical significance of these variables, psychological life stressors may not be a confounding factor in concussion evaluation.

Effect of Single-Leg Squat Speed and Depth on Dynamic Postural Control Under Single-Task and Dual-Task Paradigms.

Although single-leg squats are a common dynamic balance clinical assessment, little is known about the relationship between parameters that influence squat movement and postural control performance. The objective of this study was to determine the relationships between squat parameters (speed and depth) and postural control under single task and dual task. A total of 30 healthy college students performed single-leg squats under single task and dual task with Stroop. Random-intercepts generalized linear mixed models determined the effect of squat parameters on center of pressure (CoP) parameters. For each 1-cm·s-1 increase in squat speed, sway range (mediolateral: ß = -0.03; anteroposterior: ß = -0.05) and area (ß = -0.25) decreased, whereas sway speed (mediolateral: ß = 0.05; anteroposterior: ß = 0.29; total: ß = 0.29) increased. For each 1-cm increase in squat depth, sway range (mediolateral: ß = 0.05; anteroposterior: ß = 0.20) and area (ß = 0.72) increased, whereas sway speed (anteroposterior: ß = -0.14; total: ß = -0.14) decreased. Compared with single task, the association between total and anteroposterior sway speed and squat speed was stronger under dual task. Clinicians and researchers should consider monitoring squat speed and depth when assessing dynamic balance during single-leg squats, as these parameters influence postural control, especially under dual task.

A Randomized Controlled Trial Investigating the Feasibility and Adherence to an Aerobic Training Program in Healthy Individuals.

CONTEXT: Concussion management is moving from passive rest strategies to active interventions, including aerobic exercise therapy. Little information is available regarding the feasibility and adherence of these programs. OBJECTIVES: To determine whether an aerobic exercise training program intended for rehabilitation in people with concussion is feasible. Healthy, nonconcussed subjects were studied in this phase 1 trial. DESIGN: Phase 1 parallel-group, randomized controlled trial in a sample of healthy (nonconcussed), recreationally active university students. SETTING: Laboratory. PATIENTS: 40 healthy university students. METHODS: Participants were equally randomized to acute concussion therapy intervention (ACTIVE) training or nontraining groups. All participants completed maximal cardiopulmonary exercise tests on a stationary cycle ergometer at 2 test sessions approximately 14 days apart. During this 2-week study period, ACTIVE training participants completed six 30-minute cycling sessions, progressing from 60% to 80% of the participant's individualized maximal oxygen consumption. A subset of participants (NACTIVE = 12, Nnontraining = 11) wore physical activity monitors throughout the 2-week study period. MAIN OUTCOMES MEASURES: Study protocol and randomization effectiveness, exercise safety and adherence, and progressive intensity of the ACTIVE training procedures. RESULTS: No adverse events occurred during any exercise sessions. Twelve ACTIVE training participants (60%) completed all training sessions, and every participant completed at least 4 sessions. Heart rate increased throughout the training period (P < .001), but symptom changes and training adherence remained stable despite the progressively increasing workload. ACTIVE training participants completed approximately 30 additional minutes of physical activity on training sessions days, although that was not statistically significant (P = .20). CONCLUSIONS: University-aged students were adherent to the ACTIVE training protocol. Future research should investigate the safety and feasibility of aerobic training programs in acutely concussed individuals to determine their appropriateness as a clinical rehabilitation strategy.

Reaction Time and Joint Kinematics During Functional Movement in Recently Concussed Individuals.

OBJECTIVE: To compare movement reaction time and joint kinematics between athletes with recent concussion and matched control recreational athletes during 3 functional tasks. DESIGN: Cross-sectional. SETTING: Laboratory. PARTICIPANTS: College-aged recreational athletes (N=30) comprising 2 groups (15 participants each): (1) recent concussion group (median time since concussion, 126d; range, 28-432d) and (2) age- and sex-matched control group with no recent concussions. INTERVENTIONS: We investigated movement reaction time and joint kinematics during 3 tasks: (1) jump landing, (2) anticipated cut, and (3) unanticipated cut. MAIN OUTCOME MEASURES: Reaction time and reaction time cost (jump landing reaction time-cut reaction time/jump landing reaction time×100%), along with trunk, hip, and knee joint angles in the sagittal and frontal planes at initial ground contact. RESULTS: There were no reaction time between-group differences, but the control group displayed improved reaction time cost (10.7%) during anticipated cutting compared with the concussed group (0.8%; P=.030). The control group displayed less trunk flexion than the concussed group during the nondominant anticipated cut (5.1° difference; P=.022). There were no other kinematic between-group differences (P≥.079). CONCLUSIONS: We observed subtle reaction time and kinematic differences between individuals with recent concussion and those without concussion more than a month after return to activity after concussion. The clinical interpretation of these findings remains unclear, but may have future implications for postconcussion management and rehabilitation.

Prehospital Cervical Spine Motion: Immobilization Versus Spine Motion Restriction.

OBJECTIVE: This study aims to evaluate the efficacy of two different spinal immobilization techniques on cervical spine movement in a simulated prehospital ground transport setting. METHODS: A counterbalanced crossover design was used to evaluate two different spinal immobilization techniques in a standardized environment. Twenty healthy male volunteers (age = 20.9 ± 2.2 yr) underwent ambulance transport from a simulated scene to a simulated emergency department setting in two separate conditions: utilizing traditional spinal immobilization (TSI) and spinal motion restriction (SMR). During both transport scenarios, participants underwent the same simulated scenario. The main outcome measures were cervical spine motion (cumulative integrated motion and peak range of motion), vital signs (heart rate, blood pressure, oxygen saturation), and self-reported pain. Vital signs and pain were collected at six consistent points throughout each scenario. RESULTS: Participants experienced greater transverse plane cumulative integrated motion during TSI compared to SMR (F1,57 = 4.05; P = 0.049), and greater transverse peak range of motion during participant loading/unloading in TSI condition compared to SMR (F1,57 = 17.32; P < 0.001). Pain was reported by 40% of our participants during TSI compared to 25% of participants during SMR (χ2 = 1.29; P = 0.453). CONCLUSIONS: Spinal motion restriction controlled cervical motion at least as well as traditional spinal immobilization in a simulated prehospital ground transport setting. Given these results, along with well-documented potential complications of TSI in the literature, SMR is supported as an alternative to TSI. Future research should involve a true patient population.

Static and dynamic single leg postural control performance during dual-task paradigms.

Combining dynamic postural control assessments and cognitive tasks may give clinicians a more accurate indication of postural control under sport-like conditions compared to single-task assessments. We examined postural control, cognitive and squatting performance of healthy individuals during static and dynamic postural control assessments in single- and dual-task paradigms. Thirty participants (female = 22, male = 8; age = 20.8 ± 1.6 years, height = 157.9 ± 13.0 cm, mass = 67.8 ± 20.6 kg) completed single-leg stance and single-leg squat assessments on a force plate individually (single-task) and concurrently (dual-task) with two cognitive assessments, a modified Stroop test and the Brooks Spatial Memory Test. Outcomes included centre of pressure speed, 95% confidence ellipse, squat depth and speed and cognitive test measures (percentage of correct answers and reaction time). Postural control performance varied between postural control assessments and testing paradigms. Participants did not squat as deep and squatted slower (P < 0.001) during dual-task paradigms (≤12.69 ± 3.4 cm squat depth, ≤16.20 ± 4.6 cm · s-1 squat speed) compared to single-task paradigms (14.57 ± 3.6 cm squat depth, 19.65 ± 5.5 cm · s-1 squat speed). The percentage of correct answers did not change across testing conditions, but Stroop reaction time (725.81 ± 59.2 ms; F2,58 = 7.725, P = 0.001) was slowest during single-leg squats compared to baseline (691.64 ± 80.1 ms; P = 0.038) and single-task paradigms (681.33 ± 51.5 ms; P < 0.001). Dynamic dual-task assessments may be more challenging to the postural control system and may better represent postural control performance during dynamic activities.

Football Equipment Removal Improves Chest Compression and Ventilation Efficacy.

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.

The Clinical Utility of a Concussion Rebaseline Protocol After Concussion Recovery.

OBJECTIVE: To evaluate the clinical utility of "rebaseline" testing (ie, new baseline) before the season after an athlete's concussion recovery by (1) determining differences between baseline and rebaseline scores, and (2) comparing differences to clinical reliable change indices (RCIs). DESIGN: Retrospective cohort. SETTING: Clinical research center. PATIENTS: Thirty-four Division I collegiate athletes (16 females, 18 males; baseline age = 18.38 ± 0.78 years). INTERVENTIONS: Neurocognitive, balance, and symptom testing was conducted at 3 times: (1) original baseline, (2) final postinjury before return-to-play, and (3) rebaseline completed before the next competitive season. Physicians diagnosed concussions, and all concussed athletes' returned-to-play during the same season. MAIN OUTCOME MEASURES: Dependent variables included all neurocognitive domains, balance composite, and total symptom scores. Mean differences between sessions were compared with 80% RCIs to clinically interpret statistical findings. RESULTS: Statistically significant improvements in neurocognitive performance were observed between baseline and rebaseline sessions: psychomotor speed (F1,33 = 13.79, P = 0.001), cognitive flexibility (F1,33 = 7.99, P = 0.008), processing speed (F1,32 = 15.93, P < 0.001), executive functioning (F1,33 = 9.61, P = 0.004), and reasoning (F1,32 = 7.63, P = 0.009). We observed significant improvement in balance (F1,29 = 22.26, P < 0.001), but no difference in total symptom score (P = 0.719). Participants performed statistically better at last postinjury compared with rebaseline in visual memory (F1,29 = 5.64, P = 0.024) and complex attention (F1,31 = 11.38, P = 0.002), but worse in processing speed (F1,30 = 8.92, P = 0.006). Participants reported more symptoms (F1.28 = 10.83, P = 0.003) at rebaseline than last postinjury. No observed mean differences exceeded RCIs. CONCLUSIONS: All between-session improvements were within RCIs and therefore within expected test-retest variation. Our results suggest limited clinical utility for rebaseline assessments in the collegiate setting. CLINICAL RELEVANCE: Despite statistically significant differences between test sessions, no differences exceeded RCIs, suggesting the differences were of little clinical utility in the interpretation of neurocognitive, balance, and symptom scoring.

Does Visual Performance Influence Head Impact Severity Among High School Football Athletes?

OBJECTIVE: To compare the odds of sustaining moderate and severe head impacts, rather than mild, between high school football players with high and low visual performance. DESIGN: Prospective quasi-experimental. SETTING: Clinical Research Center/On-field. PARTICIPANTS: Thirty-seven high school varsity football players. INTERVENTIONS: Athletes completed the Nike SPARQ Sensory Station visual assessment before the season. Head impact biomechanics were captured at all practices and games using the Head Impact Telemetry System. MAIN OUTCOME MEASURES: Each player was classified as either a high or low performer using a median split for each of the following visual performance measures: visual clarity, contrast sensitivity, depth perception, near-far quickness, target capture, perception span, eye-hand coordination, go/no go, and reaction time. We computed the odds of sustaining moderate and severe head impacts against the reference odds of sustaining mild head impacts across groups of high and low performers for each of the visual performance measures. RESULTS: Players with better near-far quickness had increased odds of sustaining moderate [odds ratios (ORs), 1.27; 95% confidence intervals (CIs), 1.04-1.56] and severe head impacts (OR, 1.45; 95% CI, 1.05-2.01) as measured by Head Impact Technology severity profile. High and low performers were at equal odds on all other measures. CONCLUSIONS: Better visual performance did not reduce the odds of sustaining higher magnitude head impacts. Visual performance may play less of a role than expected for protecting against higher magnitude head impacts among high school football players. Further research is needed to determine whether visual performance influences concussion risk. CLINICAL RELEVANCE: Based on our results, we do not recommend using visual training programs at the high school level for the purpose of reducing the odds of sustaining higher magnitude head impacts.

Ice Hockey Summit II: zero tolerance for head hits and fighting.

OBJECTIVE: To present currently known basic science and on-ice influences of sport-related concussion (SRC) in hockey, building on the Ice Hockey Summit I action plan (2011) to reduce SRC. METHODS: The prior summit proceedings included an action plan intended to reduce SRC. As such, the proceedings from Summit I served as a point of departure, for the science and discussion held during Summit II (Mayo Clinic, Rochester MN, October 2013). Summit II focused on (1) Basic Science of Concussions in Ice Hockey: Taking Science Forward; (2) Acute and Chronic Concussion Care: Making a Difference; (3) Preventing Concussions via Behavior, Rules, Education and Measuring Effectiveness; (4) Updates in Equipment: their Relationship to Industry Standards; and (5) Policies and Plans at State, National and Federal Levels to reduce SRC. Action strategies derived from the presentations and discussion described in these sectors were subsequently voted on for purposes of prioritization. The following proceedings include knowledge and research shared by invited faculty, many of whom are health care providers and clinical investigators. RESULTS: The Summit II evidence-based action plan emphasizes the rapidly evolving scientific content of hockey SRC. It includes the most highly prioritized strategies voted on for implementation to decrease concussion. CONCLUSIONS: The highest priority action items identified from the Summit includes the following: (1) eliminate head hits from all levels of ice hockey, (2) change body-checking policies, and (3) eliminate fighting in all amateur and professional hockey.

Ice Hockey Summit II: zero tolerance for head hits and fighting.

This study aimed to present currently known basic science and on-ice influences of sport-related concussion (SRC) in hockey, building upon the Ice Hockey Summit I action plan (2011) to reduce SRC. The prior summit proceedings included an action plan intended to reduce SRC. As such, the proceedings from Summit I served as a point of departure for the science and discussion held during Summit II (Mayo Clinic, Rochester, MN, October 2013). Summit II focused on (1) Basic Science of Concussions in Ice Hockey: Taking Science Forward, (2) Acute and Chronic Concussion Care: Making a Difference, (3) Preventing Concussions via Behavior, Rules, Education, and Measuring Effectiveness, (4) Updates in Equipment: Their Relationship to Industry Standards, and (5) Policies and Plans at State, National, and Federal Levels To Reduce SRC. Action strategies derived from the presentations and discussion described in these sectors were voted on subsequently for purposes of prioritization. The following proceedings include the knowledge and research shared by invited faculty, many of whom are health care providers and clinical investigators. The Summit II evidence-based action plan emphasizes the rapidly evolving scientific content of hockey SRC. It includes the most highly prioritized strategies voted on for implementation to decrease concussion. The highest-priority action items identified from the Summit include the following: (1) eliminate head hits from all levels of ice hockey, (2) change body checking policies, and (3) eliminate fighting in all amateur and professional hockey.

Disclosure and non-disclosure of concussion and concussion symptoms in athletes: review and application of the socio-ecological framework.

PRIMARY OBJECTIVE: To summarize the factors associated with athletes' disclosure-and non-disclosure-of sports-related concussion and concussion symptoms within the context of the socio-ecological framework and to identify research gaps in the current literature. METHODS: Searches using electronic databases identified studies written in English, published through October 2013 and addressing some aspect of disclosure of concussion and concussion symptoms. The literature search aimed to be comprehensive and inclusive of all previous contributions. MAIN OUTCOMES AND RESULTS: Of the 30 identified studies, most originated from the US (n = 19) and sampled athletes (n = 21) and coaches (n = 10) from high school (n = 11) and college levels (n = 9). The identified reasons for non-disclosure were organized into four levels using the socio-ecological framework: intra-personal (e.g. lack of knowledge; internal pressure; sex; concussion history; n = 20 studies); inter-personal (e.g. others' knowledge/attitudes; external pressure; external support; n = 15 studies); environment (e.g. access to concussion prevention materials; sports culture; n = 4 studies); and policy (e.g. concussion-related legislation; n = 3 studies). No study examined all four levels. CONCLUSIONS: Research gaps exist concerning factors influencing athletes' disclosure of sports-related concussions and concussion symptoms. Notably, researchers have focused on intra-personal and inter-personal levels, placing less emphasis on the environment and policy levels.