Concussion in sports: the sideline assessment

Assessing Brain Processing Deficits Using Neuropsychological and Vision-Specific Tests for Concussion

INTRODUCTION

Since verbal memory and visual processing transpire within analogous cerebral regions, this study assessed (i) if a visual function can predict verbal memory performance. It also hypothesized whether neurocognitive (e.g., ImPACT) tests focusing on the Visual Memory and Cognitive Efficacy Index will predict Verbal Memory scores and (ii) if vision metrics and age can identify individuals with a history of concussion. Finally, it also hypothesized that King-Devick and near point of convergence scores alongside age considerations will identify candidates with a prior reported history of concussion.

MATERIALS AND METHODS

This observational cohort assessed 25 collegiate ice hockey players prior to the competitive season considering age (19.76 ± 1.42 years) and BMI (25.9 ± 3.0 kg/cm2). Hypothesis 1 was assessed using a hierarchical (sequential) multiple regression analysis, assessing the predictive capacity of Visual Memory and Cognitive Efficacy Index scores in relation to Verbal Memory scores. Hypothesis 2 utilized a binomial logistic regression to determine if King-Devick and near point of convergence scores predict those with a prior history of concussion.

RESULTS

Hypothesis 1 developed two models, where Model 1 included Visual Memory as the predictor, while Model 2 added the Cognitive Efficacy Index as a predictor for verbal memory scores. Model 1 significantly explained 41% of the variance. Results from Model 2 suggest that the Cognitive Efficacy Index explained an additional 24.4%. Thus, Model 2 was interpreted where only the Cognitive Efficacy Index was a significant predictor (p = 0.001). For every 1 unit increase in the Cognitive Efficacy Index, Verbal Memory increased by 41.16. Hypothesis 2's model was significant, accounting for 37.9% of the variance in those with a history of concussion. However, there were no significant unique predictors within the model as age (Wald = 1.26, p = 0.261), King-Devick (Wald = 2.31, p = 0.128), and near point of convergence (Wald = 2.43, p = 0.119) were not significant predictors individually.

CONCLUSIONS

The conflicting findings of this study indicate that baseline data for those with a history of concussion greater than one year may not be comparable to the same metrics during acute concussion episodes. Young athletes who sustain a concussion may be able to overcompensate via the visual system. Future prospective studies with larger sample sizes are required using the proposed model's objective metrics.

The Convergent Validity of the SWAY Balance Application to Assess Postural Stability in Military Cadets Recovering from Concussion

Background

Concussions are often accompanied by balance disturbances. Clinically accurate evaluation systems are often expensive, large, and inaccessible to most clinicians. The Sway Balance Mobile Application (SWAY) is an accessible method to quantify balance changes.

Purpose

To determine the known groups and convergent validity of the SWAY to assess balance after a concussion.

Study Design

Case-Control Study.

Methods

Twenty participants with acute concussion and twenty controls were recruited. At initial, one-week, and final return to activity (RTA) evaluations, all participants completed the Sports Concussion Assessment Tool (SCAT-5), and balance control measured by SWAY mBESS and NeuroCom Balance Master Sensory Organization Test (SOT). Mixed model ANOVAs were used to detect differences in SWAY mBESS and NeuroCom SOT scores with time (initial, one-week, final RTA) as the within-subjects factor and group (concussed, healthy) as the between-subjects factor. Spearman's Rho correlations explored the associations between NeuroCom SOT scores, SWAY scores, SCAT-5 symptom scores, and time in days to final RTA.

Results

The sampled population was predominantly male and age (20 ± 1), and BMI differences were insignificant between groups. The SWAY did not detect differences between healthy and concussed participants and did not detect change over time [F(2,40) = .114, p = 0.89; F(2,40)= .276, p =0.60]. When assessing the relationship between the SWAY and the SOT, no correlation was found at any time point (r = -0.317 to -0.062, p > 0.05). Time to RTA demonstrated a moderate correlation with both SCAT-5 symptom severity score (r = .693, p < 0.01) and SCAT-5 total symptom score (r = .611, p < 0.01) at the one-week follow-up.

Conclusion

The SWAY mBESS does not appear to be a valid balance assessment for the concussed patient. The SWAY mBESS in patients with concussion failed to demonstrate convergent validity and did not demonstrate an ability to validate known groups. When assessing the time to final RTA, the one-week post-initial assessment SCAT-5 symptom severity and total scores may help determine the length of recovery in this population.

Level of Evidence

Level 3.

The Clinical Utility of the Child SCAT5 for Acute Concussion Assessment

Background

The Child Sport Concussion Assessment Tool 5th Edition (Child SCAT5) was developed to evaluate children between 5 and 12 years of age for a suspected concussion. However, limited empirical evidence exists demonstrating the value of the Child SCAT5 for acute concussion assessment. Therefore, the purpose of our study was to examine differences and assess the diagnostic properties of Child SCAT5 scores among concussed and non-concussed middle school children on the same day as a suspected concussion.

Methods

Our participants included 34 concussed (21 boys, 13 girls; age = 12.8 ± 0.86 years) and 44 non-concussed (31 boys, 13 girls; age = 12.4 ± 0.76 years) middle school children who were administered the Child SCAT5 upon suspicion of a concussion. Child SCAT5 scores were calculated from the symptom evaluation (total symptoms, total severity), child version of the Standardized Assessment of Concussion (SAC-C), and modified Balance Error Scoring System (mBESS). The Child SCAT5 scores were compared between the concussed and non-concussed groups. Non-parametric effect sizes (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r=\frac{Z}{\sqrt{n}}$$\end{document}r=Zn) were calculated to assess the magnitude of difference for each comparison. The diagnostic properties (sensitivity, specificity, diagnostic accuracy, predictive values, likelihood ratios, and diagnostic odds ratio) of each Child SCAT5 score were also calculated.

Results

Concussed children endorsed more symptoms (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.45), higher symptom severity (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.44), and had higher double leg (p = 0.046, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.23), single leg (p = 0.035, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.24), and total scores (p = 0.022, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.26) for the mBESS than the non-concussed children. No significant differences were observed for the SAC-C scores (p’s ≥ 0.542). The quantity and severity of endorsed symptoms had the best diagnostic accuracy (AUC = 0.76–0.77), negative predictive values (NPV = 0.84–0.88), and negative likelihood ratios (-LR = 0.22–0.31) of the Child SCAT5 scores.

Conclusions

Clinicians should prioritize interpretation of the symptom evaluation form of the Child SCAT5 as it was the most effective component for differentiating between concussed and non-concussed middle school children on the same day as a suspected concussion.

Heart Rate Variability as a Reliable Biomarker Following Concussion: A Critically Appraised Topic

CLINICAL SCENARIO

Recent systematic reviews show conflicting information regarding the effect of concussion on cardiac autonomic function. Controlled aerobic exercise is the most popular intervention for those recovering from a concussion. There is a gap in the literature supporting the utility of objective metrics during exertional return to play protocols and rehabilitation.

CLINICAL QUESTION

Can heart rate variability (HRV) during physical exertion be a reliable biomarker over time for those who suffered a sport-related concussion?

SUMMARY OF KEY FINDINGS

A literature search produced 3 studies relevant to the clinical question. One, a prospective-matched control group cohort study, reported disturbances in HRV during physical exertion in those with a history of concussion, and identified persistent HRV dysfunction after resolution of subjective complaints, return to play, and with multiple concussive events. Second, a cross-sectional cohort study found an HRV difference in those with and without a history of concussion and in HRV related to age and sex. Finally, the prospective longitudinal case-control cohort study did not find sex or age differences in HRV and concluded that, although postconcussion HRV improved as time passed, resting HRV was not as clinically meaningful as HRV during exertional activities.

CLINICAL BOTTOM LINE

There is emerging evidence to support the use of HRV as an observable biomarker, over time, of autonomic function during physical exertion following a sport-related concussion. However, the meaningfulness of HRV data is not fully understood and the utility seems individualized to the level of athlete, age, and sex and, therefore, cannot be generalizable. In order to be more clinically meaningful and to assist with current clinical decision making regarding RTP, a preinjury baseline assessment would be beneficial as an individualized reference for baseline comparison.

STRENGTH OF RECOMMENDATION

Although HRV is not fully understood, currently, there is grade B evidence to support the use of individualized baseline exertional HRV data as comparative objective metric to assess the autonomic nervous system function, over time, following a concussive event.

Patient, Injury, Assessment, and Treatment Characteristics and Return-to-Play Timelines After Sport-Related Concussion: An Investigation from the Athletic Training Practice-Based Research Network

OBJECTIVES

To describe the patient, injury, assessment and treatment characteristics, as well as return-to-play timelines and clinical findings at discharge for adolescent patients after sport-related concussion.

DESIGN

Retrospective analysis of electronic medical records.

SETTING

Athletic training facilities of secondary school members of the Athletic Training Practice-Based Research Network (AT-PBRN).

PATIENTS

In total, 1886 patient records were reviewed. [1204 (63.8%) male, 682 (36.2%) female, age = 15.3 ± 1.9 years, height = 169.5 ± 13.5 cm, mass = 70.3 ± 17.0 kg]. Patients were diagnosed with a concussion by an athletic trainer or team/directing physician.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Descriptive analysis of patient, injury, assessment, treatment, and participation status characteristics, as well as discharge information.

RESULTS

Injury demographic forms were completed for 1886 concussion cases. A concussion-specific evaluation form was completed for 55.9% (n = 1054) of cases. Treatment documentation was completed on 829 patients (44.0% of initial documented cases). Discharge forms were completed for 750 patients (40.0% of initial documented cases). Most cases were coded as 850.9-Concussion (85.5%, n = 642) and occurred during an in-season game (49.4%, n = 308). Time lost from competition was 24.9 ± 39.9 days.

CONCLUSIONS

Most concussion cases documented in this study were not on-field emergencies, as indicated by their normal clinical examinations and the lack of immediate referral to an emergency department. However, certain aspects of the clinical examination were often not assessed during the initial evaluation. These findings describe concussion assessment and recovery in adolescents and reinforce the need for a standardized approach to concussion assessment and appropriate documentation.

A technology-enabled electronic incident report to document and facilitate management of sport concussion: A cohort study of youth and young adults

Despite the widespread awareness of concussion across all levels of sport, the management of concussion from youth to college is inconsistent and fragmented. A fundamental gap contributing to inconsistent care is the lack of a scalable, systematic approach to document initial injury characteristics following concussion. The purpose of this study was to determine differences in injury profiles and management of youth, high school, and college athletes using a mobile application for incident report documentation.A cohort study was conducted in which concussion electronic incident report data from 46 high schools and colleges, and Cleveland Clinic ambulatory concussion clinics were gathered and analyzed.In sum, 1421 (N = 88 youth, N = 1171 high school and N = 162 college) athletes with sport-related concussions were included.Despite the relative absence of red flags, youth athletes had a greater probability of being sent to the emergency department than high school and collegiate athletes. Over 60% of athletes were removed from play immediately post-injury. Injury recognition was delayed in 25% of athletes due to delayed symptom reporting (20% of males, 16% of females) or delayed symptom onset (5% of males, 9% of females). A significantly greater incidence of red flags was evident in males, and in high school and collegiate athletes compared to youth athletes.The high frequency of youth athletes sent to the emergency department, despite the absence of red flags, may be a reflection of inadequate medical coverage at youth events, ultimately resulting in unnecessary utilization of emergency medicine services. The relatively high incidence of delayed injury reporting implies that additional educational efforts targeting student-athletes and the utilization of resources to improve injury detection are warranted. The systematic collection of injury-related demographics through the electronic mobile application facilitated interdisciplinary communication and improved the efficiency of managing athletes with concussion.

Concussion Incidence and Return-to-Play Time in National Basketball Association Players: Results From 2006 to 2014

BACKGROUND

Various research efforts have studied concussions in the National Football League, Major League Baseball, and the National Hockey League. However, no study has investigated the incidence and return-to-play trends in the National Basketball Association (NBA), which this study aims to do.

HYPOTHESIS

Increased media scrutiny and public awareness, in addition to the institution of a league-wide concussion protocol, may have resulted in more conservative return-to-play practices.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

All concussions to NBA players that were publicly reported in the media from the beginning of the 2006 NBA season to the end of the 2014 season were included. The incidence and return-to-play statistics were generated by synthesizing information from publicly available records.

RESULTS

There were 134 publicly reported concussions to NBA players from the beginning of the 2006 season to the conclusion of the 2014 season, resulting in an average of 14.9 concussions per season. The incidence has not changed significantly during this time span. The average games missed after a concussion from 2006 to 2010 was 1.6, significantly less than the 5.0 games missed from 2011 to 2014, following the institution of the NBA concussion protocol (P = .023).

CONCLUSION

Although the incidence of publicly reported concussions in the NBA has not changed appreciably over the past 9 seasons, the time missed after a concussion has. While players often returned in the same game in the 2006 season, the combination of implemented policy, national coverage, medical staff awareness, and player education may have contributed to players now missing an average of 4 to 6 games after a concussion. A multitude of factors has resulted in more conservative return-to-play practices for NBA players after concussions.

Postural control deficits identify lingering post-concussion neurological deficits

Concussion, or mild traumatic brain injury, incidence rates have reached epidemic levels and impaired postural control is a cardinal symptom. The purpose of this review is to provide an overview of the linear and non-linear assessments of post-concussion postural control. The current acute evaluation for concussion utilizes the subjective balance error scoring system (BESS) to assess postural control. While the sensitivity of the overall test battery is high, the sensitivity of the BESS is unacceptably low and, with repeat administration, is unable to accurately identify recovery. Sophisticated measures of postural control, utilizing traditional linear assessments, have identified impairments in postural control well beyond BESS recovery. Both assessments of quiet stance and gait have identified lingering impairments for at least 1 month post-concussion. Recently, the application of non-linear metrics to concussion recovery have begun to receive limited attention with the most commonly utilized metric being approximate entropy (ApEn). ApEn, most commonly in the medial-lateral plane, has successfully identified impaired postural control in the acute post-concussion timeframe even when linear assessments of instrumented measures are equivalent to healthy pre-injury values; unfortunately these studies have not gone beyond the acute phase of recovery. One study has identified lingering deficits in postural control, utilizing Shannon and Renyi entropy metrics, which persist at least through clinical recovery and return to participation. Finally, limited evidence from two studies suggest that individuals with a previous history of a single concussion, even months or years prior, may display altered ApEn metrics. Overall, non-linear metrics provide a fertile area for future study to further the understanding of postural control impairments acutely post-concussion and address the current challenge of sensitive identification of recovery.

Acute sports-related traumatic brain injury and repetitive concussion

Concussions are described as functional, not structural injuries, and therefore cannot be easily detected through standard diagnostic imaging. The vast differences between individual athletes makes identifying and evaluating sport-related concussion one of the most complex and perplexing injuries faced by medical personnel. The literature, as well as most consensus statements, supports the use of a multifaceted approach to concussion evaluation on the sideline of the athletic field. Using a standardized clinical examination that is supported by objective measures of concussion-related symptoms, cognitive function, and balance provides clinicians with the ability to track recovery in an objective manner. When used in combination, these tests allow for more informed diagnosis and treatment plan, which should involve a graduated return to play progression. Establishing a comprehensive emergency action plan that can guide the on-field management of a more serious and potentially catastrophic brain injury is also essential. This review will address these management issues, as well as the recent concerns about the risk of long-term neurologic conditions believed to be associated with repetitive concussion.

Examining Neurocognitive Function in Previously Concussed Interscholastic Female Soccer Players

Awareness of sport-related concussions in soccer has gained recent attention in the medical community. Interestingly, purposeful heading-a unique yet strategic and inherent part of soccer-involves repeated subconcussive blows to the head. We divided 210 female interscholastic soccer players into control (CON [never concussed]) and experimental (EXP [previously concussed]) groups. We assessed neurocognitive performance using the Automated Neuropsychological Assessment Metrics computer program before and after the players' competitive season. Headers were recorded at all sanctioned matches. Data were analyzed using a series of one-way analyses of covariance and t tests. Both groups essentially played in the same number of games (EXP = 16.1 vs. CON = 16.1) and had an equal number of total headers (EXP = 24.9 vs. CON = 24.3). Additionally, headers per game were surprisingly low in both groups (1.4 in EXP vs. 1.3 in CON). Unexpectedly, there were no significant differences between the EXP and CON groups across all dependent variables measured (p > .05). This study suggests that although previously concussed players involve themselves in purposeful heading (i.e., subconcussive insults) throughout a competitive season, there appear to be no negative consequences on neuropsychological test performance or concussion-related symptoms. Additional research is needed to determine what may result during the course of a playing career.

National Athletic Trainers' Association position statement: management of sport concussion

OBJECTIVE

To provide athletic trainers, physicians, and other health care professionals with best-practice guidelines for the management of sport-related concussions.

BACKGROUND

An estimated 3.8 million concussions occur each year in the United States as a result of sport and physical activity. Athletic trainers are commonly the first medical providers available onsite to identify and evaluate these injuries.

RECOMMENDATIONS

The recommendations for concussion management provided here are based on the most current research and divided into sections on education and prevention, documentation and legal aspects, evaluation and return to play, and other considerations.

The balance error scoring system learned response among young adults

BACKGROUND

Concussion management practices are important for athlete safety. Baseline testing provides a benchmark to which post-injury assessments are compared. Yet few neurophysical concussion assessment studies have examined learned response. The Balance Error Scoring System (BESS) measures postural stability through 6 conditions by counting the errors committed during each condition. In a study examining the performance of high school-aged athletes on the BESS, the learned response extinguished in 3 weeks. However, this phenomenon has not been studied in the college-aged population.

HYPOTHESIS

College-aged adults performing the BESS will have a learned response at 1 and 2 weeks but would have no change from baseline at or after 3 weeks, as found previously in high school-aged subjects.

STUDY DESIGN

Randomized controlled clinical trial.

METHODS

Three groups of college-aged adults ages 18 to 26 years were tested using the BESS at scheduled intervals. Each subject was randomly assigned into 1 of 3 groups to determine learned response at weeks 1, 2, and 4. Changes in pretest and posttest BESS scores were compared using the paired t test for each group at week 4 and other intervals. Differences among groups were compared using analysis of variance for means or the chi-square test for proportions.

RESULTS

After 4 weeks, participants exhibited a mean (95% confidence interval) change from pretest baseline of -2.30 (-4.75, 0.16) in the control group (P = 0.065), -3.13 (-4.84, -1.41) in Group 1 (P = 0.001), and -2.57 (-5.28, 0.15) in Group 2 (P = 0.063). There were no statistically significant differences between the 3 groups for week 4 BESS score (P = 0.291) or changes from baseline to week 4 BESS scores (P = 0.868). Overall, participant score changes from baseline to the 4-week follow-up still showed a statistically significant or close to significant reduction across the 3 groups, indicating the learned response did not extinguish after 4 weeks.

CONCLUSION

Repeated BESS testing results in a learned effect in college-aged adults did not extinguish after 4 weeks. These results question the ability of the BESS to assess an athlete's balance deficits following a concussion.

CLINICAL RELEVANCE

Given learned response did not extinguish in this sample and the BESS has a minimal detectable change/reliable change index of 7 or greater, the effectiveness of the BESS to assess balance may be limited.

Prevalence of neurocognitive and balance deficits in collegiate aged football players without clinically diagnosed concussion

STUDY DESIGN

Prospective cohort.

OBJECTIVES

To identify the prevalence of neurocognitive and balance deficits in collegiate football players 48 hours following competition.

BACKGROUND

Neurocognitive testing, balance assessments, and subjective report of symptoms are a commonly used test battery in examining athletes when concussion is suspected. Previous literature suggests many concussions go unreported. Little research exists examining the prevalence of neurocognitive or balance deficits in athletes who do not report concussion-like symptoms to a health care provider.

METHODS

Forty-five Division IA collegiate football players participated in this study. Preseason baseline scores using the Balance Error Scoring System, the Immediate Post-Concussion Assessment and Cognitive Testing, and the Postconcussion Symptom Scale were compared to posttest results obtained 48 hours following a game. Prevalence of symptoms was analyzed and reported.

RESULTS

Thirty-two (71%) of the 45 athletes tested demonstrated at least 1 deficit in either the Postconcussion Symptom Scale, Balance Error Scoring System, or at least 1 composite score of the Immediate Post-Concussion Assessment and Cognitive Testing. Nineteen of the 32 subjects demonstrated a change in 2 or more categories of neurocognitive and balance function.

CONCLUSION

In a cohort of football players tested 48 hours following their last game of the season, who did not seek medical attention related to a concussion, a significant number demonstrated limitations in neurocognitive and balance performance, suggesting that further research may need to be performed to improve recognition of an athlete's deficits and to improve the ability to assess concussion.

LEVEL OF EVIDENCE

Differential diagnosis/symptom prevalence, level 3b.

A preliminary investigation of motor evoked potential abnormalities following sport-related concussion

BACKGROUND

Assessment of concussion is primarily based on self-reported symptoms, neurological examination and neuropsychological testing. The neurophysiologic sequelae and the integrity of the corticomotor pathways could be obtained by evaluating motor evoked potentials (MEPs).

OBJECTIVES

To compare MEPs obtained through transcranial magnetic stimulation (TMS) in acutely concussed and non-concussed collegiate athletes.

METHODS

Eighteen collegiate athletes (12 males, six females, aged 20.4 +/- 1.3 years) including nine subjects with acute concussion (<or=24 hours) matched to nine control subjects. TMS was applied over the motor cortex and MEP responses were recorded from the contralateral upper extremity. MEP thresholds (%), latencies (milliseconds per metre) and amplitudes were assessed. Central motor conduction time (CMCT) was calculated from MEP, M response and F wave latencies. Testing was performed on days 1, 3, 5 and 10 post-concussion.

RESULTS

Ulnar MEP amplitudes were significantly different between post-concussion days 3 and 5 (F(3,48) = 3.13, p = 0.041) with smaller amplitudes recorded on day 3 (0.28 +/- 0.10 ms m(-1)). Median MEP latencies were significantly longer (F(3,48) = 4.53, p = 0.023) 10 days post-concussion (27.1 +/- 1.4 ms m(-1)) compared to day 1 (25.7 +/- 1.5 ms m(-1)). No significant differences for motor thresholds or CMCTs were observed (p > 0.05).

CONCLUSION

MEP abnormalities among acutely concussed collegiate athletes provide direct electrophysiologic evidence for the immediate effects of concussion.

Rodeo medicine: considerations in event coverage

Rodeo is an increasingly popular but dangerous sport, with injury rates higher than any other sport. While there are several organizations that oversee many of the rodeo competitions in the U.S., most events are non-sanctioned. Several factors contribute to the risk for injury, and medical coverage is usually volunteer-based. This article describes the common events that occur in most rodeo competitions, highlights the injuries most often documented in rodeo injury reporting, and suggests guidelines for preparation of medical coverage of a typical rodeo event.