American Medical Society for Sports Medicine position statement on concussion in sport

Concussion Symptom Characteristics and Resolution in 20 United States High School Sports, 2013/14-2017/18 Academic Years

BACKGROUND

High school (HS) sport-related concussions (SRCs) remain a public health concern in the United States.

OBJECTIVE

To describe patterns in symptom prevalence, symptom resolution time (SRT), and return-to-play time (RTP) for SRCs sustained in 20 HS sports during the 2013/14-2017/18 academic years.

METHODS

A convenience sample of athletic trainers reported concussion information to the HS RIOTM surveillance system. Symptom prevalence, average number of symptoms, and SRT and RTP distributions were examined and compared by event type (practice, competition), injury mechanism (person contact, nonperson contact), sex, and contact level (collision, high contact, and low contact) with chi-square tests and Wilcoxon rank-sum tests.

RESULTS

Among all SRCs (n = 9542), headache (94.5%), dizziness (73.8%), and difficulty concentrating (56.0%) were commonly reported symptoms. On average, 4.7 ± 2.4 symptoms were reported per SRC. Overall, 51.3% had symptoms resolve in <7 d, yet only 7.9% had RTP < 7 d. Differential prevalence of amnesia was seen between practice and competition-related SRCs (8.8% vs 13.0%; P < .001); nonperson-contact and person-contact SRCs (9.3% vs 12.7%; P < .001); and female and male SRCs in low-contact sports (5.8% vs 17.5%; P < .001). Differential prevalence of loss of consciousness was seen between practice and game-related SRCs (1.3% vs 3.2%; P < .001); and female and male SRCs in high contact sports (1.2% vs 4.0%; P < .001). Differential longer SRT (>21 d) was seen between new and recurrent SRCs (9.4% vs 15.9%; P < .001).

CONCLUSION

Headache was the most commonly reported symptom. Notable group differences in the prevalence of amnesia, loss of consciousness, and SRT may be associated with more severe SRCs, warranting further attention.

Concussion Office Based Rehabilitation Assessment: A Novel Clinical Tool for Concussion Assessment and Management

The Concussion Office Based Rehabilitation Assessment (COBRA) is a novel tool constructed to ensure a comprehensive assessment of patients who may have sustained a concussion. The SCAT-5 (Sport Concussion Assessment Tool) has long been the gold standard for concussion assessment, however, it was designed as a sideline tool and its utility can be seen to decrease after a few days post-concussion. It also does not prompt evaluation of all the phenotypes of concussion. As such, the COBRA was created to assess the majority of potential manifestations of concussion in the office setting a day or two after an injury has been sustained. The COBRA utilizes the eight phenotypes of concussion as a guide to assess each of the potential biopsychosocial features that can be associated with these injuries and can be used to guide evidence-based treatments. Through early identification of concussion phenotypes, the clinician may start optimal treatment and hopefully prevent prolonged recovery and persisting symptoms.

Increased Risk of Musculoskeletal Injury Following Sport-Related Concussion: A Perception-Action Coupling Approach

Recent studies have concluded that athletes have increased risk of musculoskeletal injury following sport-related concussion. While an underlying explanation is still unknown, perceptual-motor control may be implicated in this increased risk. Some authors have purported that indirect perception (i.e., a "top-down" view of neuromuscular control) may be disrupted following sport-related concussion. Direct perception theory states that the athlete and environment are inextricably linked in a continuous perception-action coupling loop. That is, the athlete is able to directly perceive opportunities for action (e.g., "affordances") in the environment. Based on these notions, the aim of the current paper was to introduce a theoretical model that argues that sport-related concussion may dysregulate the direct perception process, potentially increasing behavioral risk of musculoskeletal injury during sport. Our model is integrated with a sport-related concussion clinical treatment model, which highlights individualized profiles that characterize the heterogeneous response to sport-related concussion. These profiles have a typical constellation of symptoms (e.g., anxiety, fatigue, ocular dysfunction, etc.), which themselves have been associated with disrupted perception-action coupling, independent of sport-related concussion. Therefore, we argue that athletes who have not re-established perception-action coupling loops following sport-related concussion may be at increased risk of subsequent musculoskeletal injury.

Evaluation of current post-concussion protocols

The growing number of concussions and mild traumatic brain injuries (mTBI) with the lack of evidence-based treatment options is a continuous health concern. This creates problems when evaluating and providing efficacious symptom management to patients suffering from post-concussion syndrome (PCS). Numerous pharmacological and non-pharmacological agents have been utilized in an attempt to treat PCS. Some of these approaches include physical therapy, analgesics, antidepressants, and nutraceuticals. Although these treatments have had some success, there has been inconsistent outcomes, with some examples of patients' symptoms worsening. Among pharmaceutical agents, fluoxetine has been a popular choice for the symptom management of PCS. Although some patients have had symptom resolution with the use of fluoxetine, there is still a lack of conclusive data. Of the several biochemical changes that occur in a patient's brain following a concussion, an increase in reactive oxygen species (ROS) is of particular concern. In order to counteract the responses of the brain, antioxidants, such as ascorbic acid, have been utilized to reverse the damaging cellular effects. However, this may inadvertently cause an increase in ROS, rather than a reduction. Although there is a lack of consistency in exactly when each treatment was used in the post-injury interval, it is important that we analyze the strengths and weaknesses of the most commonly used agents due to the lack of a set protocol. The studies were chosen in a non-exhaustive manner and were not consistent in patients' post-injury intervals, in addition to other baseline characteristics. However, over-arching claims that some treatments may benefit more than others can be made. This review evaluates both the pharmaceutical and non-pharmaceutical protocols that are most commonly utilized in post-concussive patients for their efficacy in treatment of post-concussive syndrome (PCS).

The relationship between depressive symptoms, somatic complaints, and concussion history with poor sleep in collegiate athletes

OBJECTIVE

Ongoing exploration of factors related to poor sleep in collegiate athletes is important as understanding of the risks and consequences of poor sleep in this specific population increases.

DESIGN

Retrospective cohort study.

SETTING

University in the Pacific Northwest.

PARTICIPANTS

One-hundred thirty-seven male and female collegiate athletes across 5 collision, contact, and limited contact team sports.

MEASUREMENTS

Depressive symptoms (Patient Health Questionnaire 9; PHQ-9), anxiety symptoms (General Anxiety Disorder 7; GAD-7), and somatic complaints (Patient Health Questionnaire 15; PHQ-15). Sleep quality (Pittsburgh Sleep Quality Index; PSQI) used both a cutoff score ≥6 and a cutoff score of ≥8, indicating "poor sleep quality" to reduce threats to divergent validity.

RESULTS

Poor sleep quality as defined by PSQI ≥ 6 was present in 53% of athletes, and as defined by PSQI ≥ 8 was identified in 33.5% of the cohort. There were no differences in the incidence of poor sleepers between sport, race/ethnicity, or sex. Multiple regression analysis revealed that depressive symptoms, somatic complaints, Caucasian race, male sex, and number of concussions were significant predictors of poor sleep (P < .05). The model accounted for 43% of the variance in PSQI and primarily by depressive symptoms explaining 9% of reported sleep quality variability. Anxiety symptoms, sport category, and history of migraines were not significant predictors of poor sleep quality.

CONCLUSIONS

A high incidence of poor sleep among collegiate athletes was observed regardless of sport, and may be related to depressive symptoms, somatic complaints, Caucasian race, male sex, and historical number of concussions.

Concussion Symptom Cutoffs for Identification and Prognosis of Sports-Related Concussion: Role of Time Since Injury

BACKGROUND

Symptom reporting with scales such as the Post-Concussion Symptom Scale (PCSS) is one of the most sensitive markers of concussed status and/or recovery time, It is known that time from injury until initial clinic visit affects symptom presentation and recovery outcomes, but no study to date has evaluated changes in clinical cutoff scores for the PCSS based on earlier versus later clinical presentation postconcussion.

PURPOSE

To evaluate if time since injury after sports-related concussion (SRC) affects clinical cutoff scores for total PCSS and PCSS factors in differentiating athletes with SRC from healthy controls and predicting prolonged recovery (>30 days) after SRC.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A chart review was conducted of clinical data from patients with SRC (age, 13-25 years; n = 588; female, n = 299) who presented to concussion specialty clinics. Participants were categorized on the basis of time from injury: early (≤7 days; n = 348) and late (8-21 days; n = 240). Outcomes were total symptom severity (ie, total PCSS score) and total score for each of 4 symptom factors (cognitive/migraine/fatigue [CMF], affective, sleep, and somatic). Area under the curve (AUC) analyses were conducted using the Youden index to optimize sensitivity and specificity cutoffs.

RESULTS

In the early group, the CMF factor (cutoff, ≥7; AUC = 0.944), affective factor (cutoff, ≥1; AUC = 0.614), and total PCSS (cutoff, ≥7; AUC = 0.889) differentiated athletes with SRC from controls. In the late group, the CMF factor cutoff was reduced (cutoff, ≥4; AUC = 0.945), while the total PCSS score (cutoff, ≥7; AUC = 0.892), affective factor (cutoff, ≥1; AUC = 0.603), and sleep factor (cutoff, ≥1; AUC = 0.609) remained the same. In the early cohort, the CMF factor was the strongest predictor of protracted recovery (cutoff, ≥23; AUC = 0.717), followed by the total PCSS (cutoff, ≥39; AUC = 0.695) and affective factor (cutoff, ≥2; AUC = 0.614). The affective factor (cutoff, ≥1; AUC = 0.642) and total PCSS (cutoff, ≥35; AUC = 0.592) were significant predictors in the late cohort, but the cutoff threshold was reduced.

CONCLUSION

The findings indicate that PCSS symptom clinical cutoffs for identifying injury and recovery prognosis change on the basis of time since injury. Specifically, the combination of CMF, affective, and sleep factors is the best differentiator of athletes with SRC from controls regardless of time since injury. Furthermore, the CMF factor is the most robust predictor of prolonged recovery if the patient is within 1 week of SRC, whereas the affective factor is the most robust predictor of prolonged recovery if the patient is within 2 to 3 weeks of SRC.

Association of time to initial clinic visit with prolonged recovery in pediatric patients with concussion

OBJECTIVE

No studies to date have investigated the role of early clinical care in time to recovery from concussion in a pediatric population. The purpose of this study was to investigate the role of clinic presentation timing (≤ 7 days [early] compared to 8-20 days [late] from injury) in concussion assessment performance and risk for prolonged recovery (> 30 days) in pediatric concussion.

METHODS

This study is a retrospective cross-sectional study from a concussion clinic between April 2016 and January 2019, including 218 children and adolescents with diagnosed concussion, separated based on clinic presentation timing following injury: early (≤ 7 days) and late (8-20 days). Outcomes were recovery time, Postconcussion Symptom Scale (PCSS), Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Vestibular/Ocular Motor Screen (VOMS), and demographics, medical history, and injury information. A general linear model and chi-square analyses were used to assess differences between early and late presentation, along with logistic regression, to predict prolonged recovery (> 30 days).

RESULTS

Those with early presentation reported higher symptoms on VOMS subtests (79%-85%) compared to those with late presentation (61%-78%), with the exception of near-point of convergence distance and visual motion sensitivity (VMS). The strongest predictor of prolonged recovery was number of days to first clinic visit (OR 9.8). Positive VMS (OR 5.18), history of headache/migraine (OR 4.02), and PCSS score (OR 1.04) were also predictive of prolonged recovery.

CONCLUSIONS

Despite patients in the early presentation group presenting with more positive VOMS scores, the early presentation group recovered sooner than patients in the late presentation group. Even after controlling for vestibular dysfunction, history of headache or migraine, and total symptom severity, days to first visit remained the most robust predictor of recovery > 30 days. These findings suggest that early, specialized medical care and intervention for children and adolescents with recent concussion is associated with normal recovery time. Clinicians should educate children and parents on the potential importance of early treatment to improve the odds of positive outcomes following concussion.

Clinical predictors of post-injury anxiety in adolescent patients following concussion

The purpose of the current study was to examine predictors (e.g., pre-injury anxiety and sub-types, concussion symptom severity, neurocognitive performance, and vestibular/ocular-motor impairment) of post-injury anxiety scores following concussion among youth aged 10-18 years. This observational cohort study enrolled patients (n = 129) within 30 days of a diagnosed concussion. Patients completed Screening for Child Anxiety Related Disorders-Child Reports (SCARED-C), Generalized Anxiety Disorder-7 (GAD-7), Post-concussion Symptom Scale, neurocognitive testing, and Vestibular-Ocular Motor Screening. Logistic regression analyses were conducted to evaluate the role of risk factors and clinical outcomes as predictors of mild (GAD-7 > 5) and moderate levels (GAD-7 > 10) of post-injury anxiety. Twenty-two percent (n = 28) of patients reported clinical levels of pre-injury anxiety, and 13% (n = 17) reported clinical levels of post-injury anxiety. The logistic regression model predicting mild or greater anxiety was significant (R² = 31.7%; p < 0.001) and supported pre-injury panic symptoms (OR = 1.38) and total symptom severity (OR = 1.04) as the most robust predictors. The logistic regression model predicting clinical anxiety was significant (R² = 47.2%; p < 0.001) and supported non-SRC injury type (OR = 9.48), vestibular dysfunction (OR = 1.74) and pre-injury panic symptoms (OR = 1.57) as the most robust predictors. Results suggest that clinicians should employ measures of pre-injury and post-injury emotional functioning when evaluating and treating concussion among adolescents. Moreover, these results highlight the importance of assessing different types of pre-injury and post-injury anxiety in the context of concussion management.

Concussion Epidemiology in Youth Sports: Sports Study of a Statewide High School Sports Program

BACKGROUND

Current research on concussion incidence in youth athletes (age <18 years) is small and limited by variability in injury reporting and diagnostic methodology.

HYPOTHESIS

Concussion injuries commonly occur in high school sports programs. The likelihood of concussion among student-athletes (aged 13-18 years) depends on the sport they are participating in as well as the sex of the athlete.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A retrospective analysis of all Hawaii high school athletes aged 13 to 18 years participating in 14 sports from 2011 through 2017 was performed as part of a statewide standardized concussion assessment and management program.

RESULTS

A total of 5993 concussions were identified among 92,966 athletes. The overall concussion rate was 0.96 (95% CI, 0.94-0.99). Girls' judo had the highest concussion rate (1.92; 95% CI, 1.68-2.17) followed by football (1.60; 95% CI, 1.53-1.66). The concussion rate for boys (1.0; 95% CI, 0.97-1.03) was higher than that for girls (0.91; 95% CI, 0.87-0.95); however, in 4 of the 5 sports in which both girls and boys participated, girls had a higher rate of concussion injury.

CONCLUSION

The likelihood of concussion among student-athletes aged 13 to 18 years may be higher than previously thought and varies depending on sport and sex.

CLINICAL RELEVANCE

Epidemiologic data on concussion injury in children and adolescents are useful in accurately determining the relative risks of high school sports participation and may be valuable in determining the appropriate allocation of health care and scholastic resources for student-athletes, as well as the impact of rule and training modifications designed to improve participant safety.

Sport Concussion Assessment Tool: baseline and clinical reference limits for concussion diagnosis and management in elite Rugby Union

OBJECTIVES

Rugby Union has adapted the Sports Concussion Assessment Tool (SCAT) into an abridged off-field concussion screen and the complete SCAT is used during diagnostic screens performed after head impact events. No firm guidelines exist as to what should be considered "abnormal" and warrant further evaluation. This study evaluates SCAT performances in 13,479 baseline SCAT assessments, and proposes clear reference limits for each sub-component of the SCAT5. Baseline reference limits are proposed to guide management of baseline testing by identifying abnormal sub-tests, enhancing the clinical validity of baseline screens, while clinical reference limits are identified to support concussion diagnosis when no baseline is available.

DESIGN

Cross sectional census sample.

METHODS

13,479 baseline SCATs from 7565 elite male rugby players were evaluated. Baseline reference limits were identified for each sub-test as the sub-test result achieved by approximately 5% of the population, while clinical references limits corresponded to the sub-test score achieved by as close as possible to 50% of the cohort.

RESULTS

Players reported symptoms 35% (95% CI 1.29-1.42) more frequently during SCAT5 than SCAT3 baseline assessments (mean 1.4±2.7 vs 1.0±2.4). Ceiling effects were identified for many cognitive sub-tests within the SCAT. Baseline and Clinical reference limits corresponding to the worst performing 5th percentile and 50th percentile were described.

CONCLUSIONS

Targeted baseline re-testing should be repeated when abnormal sub-tests are identified according to proposed baseline reference limits, while a more conservative clinical reference limit supports concussion diagnosis during screens in diagnostic settings.

Association of sleep symptoms with mood and vestibular subtypes following sport-related concussion

Sport-related concussion (SRC) is a heterogenous injury with diverse symptoms and impairments that can be aggregated into clinical subtypes (cognitive, headache/migraine, vestibular, ocular-motor, anxiety/mood). Sleep disruption has been defined as potential exacerbating conditions that may accompany the five clinical subtypes. The authors sought to better characterize the role of impaired sleep in each clinical subtype and to identify other risk factors for sleep impairment after SRC. 281 patients (15.3 ± 2.1 years) aged 10-22 years within 21 days of SRC completed the Post-Concussion Symptom Scale (PCSS), the Vestibular/Ocular Motor Screening (VOMS), and a clinical assessment to identify clinical subtype. Subjects were then divided into HIGH (≥7; n = 82) and LOW (≤3; n = 132) sleep symptom groups for comparison. HIGH participants had greater proportions of females (p < 0.001), history of psychiatric disorder (p < 0.001); total PCSS (p < 0.001); and impairment on all VOMS items (p < 0.001). HIGH participants were associated with mood/anxiety (p < 0.001), vestibular (p = 0.003) and ocular (p = 0.03) subtypes. Results of a logistic regression (LR) model with adjusted odds ratios (OR) to predict HIGH sleep symptoms supported anxiety/mood profile (OR = 2.98), vestibular profile (OR = 2.81), psychiatric history (OR = 4.99), and history of motion sickness (OR = 2.13) as significant predictors. Prescribing behavioral and sleep interventions may improve outcomes in cases where these factors co-occur.

Improving Concussion Management by Including Driving Recommendations for Adolescents with Concussions: A Quality Improvement Project

Introduction

Motor vehicle collisions are the leading cause of death in adolescents. A concussion is a common injury sustained by adolescents and may impair their driving abilities during the acute phase of recovery. Healthcare providers do not consistently perform counseling of adolescents regarding driving after a concussion. This quality improvement project's goal was to increase the incidence of primary care sports medicine physicians providing driving recommendations to 75% of adolescents who suffered from concussions.

Methods

Between August 2017 to August 2018, a "smart phrase" implemented in the electronic health record system reminded providers during office visits to provide driving recommendations to patients 15 years old and older who presented to the sports medicine clinic for evaluation of concussion. Performing monthly retrospective chart reviews determined the frequency of patients who received driving recommendations during the initial visit.

Results

We achieved the goal of providing driving recommendations to 75% of concussed patients by the second month. This progress was maintained through the remainder of the year, except for 1 month (December). Forty-three percent of patients with concussions evaluated met inclusion criteria, and of those, 48% were actively driving before their concussion. The most common medical reason for restricting driving was vestibular or ocular dysfunction.

Conclusion

This quality improvement project showed that providing driving instructions to concussion patients by implementing a smart phrase into the electronic health record system was impactful and sustainable.

Early Aerobic Exercise for the Treatment of Acute Pediatric Concussions

Sport-related concussion is a common injury that has garnered the attention of the media and general public because of the potential for prolonged acute symptoms and increased risk for long-term impairment. Currently, a growing body of evidence supports the use of various therapies to improve recovery after a concussion. A contemporary approach to managing concussion symptoms is to use aerobic exercise as treatment. To date, several studies on both pediatric and adult patients have established that controlled aerobic exercise is a safe and effective way to rehabilitate patients experiencing delayed recovery after concussion. However, less is known about the utility of an early exercise protocol for optimizing recovery after acute concussion and reducing the risk for persistent postconcussive symptoms, particularly in pediatric populations. Thus, the purpose of our paper was to review and evaluate the available literature on the implementation of aerobic exercise for the treatment of acute pediatric concussion.

Recommendations for initial examination, differential diagnosis, and management of concussion and other head injuries in high-level football

Head injuries can result in substantially different outcomes, ranging from no detectable effect to transient functional impairments to life‐threatening structural lesions. In high‐level international football (soccer) tournaments, on average, one head injury occurs in every third match. Making the diagnosis and determining the severity of a head injury immediately on‐pitch or off‐field is a major challenge for team physicians, especially because clinical signs of a brain injury can develop over several minutes, hours, or even days after the injury. A standardized approach is useful to support team physicians in their decision whether the player should be allowed to continue to play or should be removed from play after head injury. A systematic, football‐specific procedure for examination and management during the first 72 hours after head injuries and a graduated Return‐to‐Football program for high‐level players have been developed by an international group of experts based on current national and international guidelines for the management of acute head injuries. The procedure includes seven stages from the initial on‐pitch examination to the graduated Return‐to‐Football program. Details of the assessments and the consequences of different outcomes are described for each stage. Criteria for emergency management (red flags), removal from play (orange flags), and referral to specialists for further diagnosis and treatment (persistent orange flags) are provided. The guidelines for return to sport after concussion‐type head injury are specified for football. Thus, the present paper presents a comprehensive procedure for team physicians after a head injury in high‐level football.

Medical Disqualification Following Concussion in Collegiate Student-Athletes: Findings from the CARE Consortium

BACKGROUND

The absence of evidence-based guidelines make medical disqualification (MDQ) following concussion one of the most challenging decision-making processes faced by sports medicine professionals.

OBJECTIVE

We aimed to compare premorbid and postmorbid factors between student-athletes that were and were not medically disqualified from sport following a concussion.

METHODS

Among 1832 student-athletes diagnosed with concussion within the CARE Consortium, 53 (2.9%) were medically disqualified (MDQ +) and 1779 (97.1%) were not medically disqualified (MDQ-). We used contingency tables and descriptive statistics for an initial evaluation of a broad list of premorbid and postmorbid factors. For those factors showing association with MDQ status, we calculated odds ratios and 95% confidence intervals for the odds of being MDQ + in the presence of the identified factor.

RESULTS

History of 2 (OR: 3.2, 95% CI 1.5, 6.9) or 3 + (OR: 7.4, 95% CI 3.4, 15.9) previous concussions; 1 + headaches in past 3 months (OR: 1.8, 95% CI 1.0, 3.2); immediate removal from play (OR: 2.4, 95% CI 1.2, 4.9); alcohol (OR: 2.6, 95% CI 1.2, 5.4), tobacco (OR: 3.3, 95% CI 1.1, 9.5), or marijuana use since injury (OR: 5.4, 95% CI 1.5, 19.0); as well as prolonged recovery due to mental health alterations (OR: 5.3, 95% CI 2.0, 14.1) or motivation/malingering (OR: 7.5, 95% CI 3.3, 17.0) increased odds of being MDQ + . The MDQ + group took longer to become asymptomatic relative to the MDQ- group (MDQ + : 23.5 days, 95% CI 15.8, 31.2; MDQ-: 10.6 days, 95% CI 9.5, 11.6; p < 0.001).

CONCLUSIONS

MDQ following concussion was relatively rare. We identified three patterns related to MDQ following concussion: (1) concussion and headache history were the only premorbid factors that differed (2) initial concussion presentation was more severe and more immediate in the MDQ + group, and (3) post-concussion recovery outcomes expressed the greatest differences between groups.

Going Beyond the State Law: Investigating High School Sport-Related Concussion Protocols

CONTEXT

State laws provide general guidelines for sport-related concussion (SRC) management, but do not comprehensively address the multiple layers of management for this complex injury. While high schools are encouraged to develop a SRC protocol that includes both state law tenets and additional management practices, the execution of this warrants examination.

OBJECTIVE

To investigate state law compliance and practice components included in high school SRC protocols, and determine whether the degree of sports medicine coverage influenced protocol quality.

DESIGN

Qualitative document analysis.

SETTING

High school athletics.

PARTICIPANTS

In total, 184 Pennsylvania high schools [24.3% of schools statewide; full-time athletic trainer=149, part-time athletic trainer=13, missing=21] voluntarily provided copies of their protocol from the 2018-2019 academic year.

MAIN OUTCOME MEASURES

Four athletic trainers conducted document analyses using a 67-item component analysis guide. Frequencies were computed for included protocol components related to the state law, preparticipation and prevention, recognition and assessment, and management. The difference in the total number of included components (max 60) by sports medicine coverage was assessed using a Mann-Whitney U test.

RESULTS

There was heterogeneity in components included in the submitted protocols. Only 23.4% included all mandatory state law tenets. Immediate removal from play was noted in 67.4% of protocols, while only 1.6% contained prevention strategies. Return-to-play was addressed more frequently than return-to-learn (74.5% versus 32.6%). The sample had a mean of 15.5±9.7 total components per protocol. Schools with full-time sports medicine coverage had significantly more protocol components than those with part-time athletic trainers (15 [8.5-22.5] versus 6 [3-10.5] median components; U = 377.5, p < .001) Conclusions: School-level written SRC protocols were often missing components of the state law and additional best practice recommendations. Full-time sports medicine coverage in high schools is recommended to increase SRC protocol and healthcare quality.

Average symptom severity and related predictors of prolonged recovery in pediatric patients with concussion

The purpose of this study is to compare the predictive utility of total number of individual symptoms endorsed, total symptom severity, and average symptom severity on prolonged recovery among children/adolescents with a concussion. Patients (n = 115) completed the Post-Concussion Symptom Scale (PCSS) at their initial clinical visit (7.9 ± 6.6 days) days post-injury. PCSS outcomes were total symptom severity (i.e., total PCSS score), number of symptoms endorsed (i.e., number out of 22-items on the PCSS with a symptom score >0) and average symptom severity (i.e., mean of scores for each of the 22-items on the PCSS, not just endorsed symptoms). Logistic regression was performed with all symptom measures and recovery time >30 days as the binary outcome. Logistic regression indicated that average symptom severity (OR = 1.9; p = 0.01) and later time to first clinical visit (OR = 5.0; p < 0.001) were the only significant predictors of recovery time. Average symptom severity at initial clinic visit and earlier clinical visit may be a better predictor of recovery time than total number of symptoms endorsed or total symptom severity among children and adolescents.

Prognosis for Persistent Post Concussion Symptoms using a Multifaceted Objective Gait and Balance Assessment Approach

BACKGROUND

Concussion prognosis is a challenging clinical task. Identification of measures useful for persistent symptom risk can help optimize treatment pathways and allow clinicians to offer appropriate anticipatory guidance.

RESEARCH QUESTION

Can a multifaceted single/dual-task postural control assessment within one week of a diagnosed concussion identify the odds of developing persistent post-concussion symptoms (PPCS; symptoms that persist for more than 28 days post-concussion)?

METHODS

We conducted a prospective cohort study of youth and young adult athletes who were evaluated within 7 days of injury, and followed until they no longer reported concussion symptoms. Participants were grouped into those who developed PPCS and those who did not. During the initial evaluation, participants completed a postural control evaluation in single/dual-task conditions. We calculated six gait performance variables (in single/dual-task conditions), nine quiet stance performance variables, and three cognitive task performance (standing and walking) variables. We conducted between-group comparisons to identify candidate PPCS prognostic variables, and multivariable models to adjust for covariates (age, post-injury evaluation time, history of concussion, and BMI).

RESULTS

Sixty-six participants completed the study: 24% reported PPCS (mean age = 16.9 ± 3.5 years; 50% female; evaluated 4.2 ± 1.9 days post-injury) and 74% (mean age = 18.3 ± 3.0 years; 52% female; evaluated 3.5 ± 1.6 days post-injury) did not. Between-group comparisons indicated greater dual-task transverse plane center-of-mass (COM) range of motion (ROM) (13.1 ± 4.3 vs. 9.9 ± 2.5 degrees; p = 0.013) and lateral step variability (5.1 ± 1.4 vs. 4.0 ± 1.2 cm; p = 0.003) for the PPCS group relative to the no PPCS group. After multivariable modeling, dual-task transverse plane COM ROM (adjusted odds ratio = 1.34, 95% CI = 1.07, 1.68) and lateral step variability (adjusted odds ratio = 1.85, 95% CI = 1.13, 3.05) were significantly associated with PPCS.

SIGNIFICANCE

Dual-task transverse plane movement and lateral step variability demonstrate viable prognostic ability for PPCS among youth and young adult athletes and, along with other established factors, may add incremental value to PPCS prognosis models.

Presence of Neck or Shoulder Pain Following Sport-Related Concussion Negatively Influences Recovery

Our objective was to examine the effect of current neck or shoulder pain on concussion outcomes. Variables included symptom resolution and return-to-sport time, symptom severity, amount of school missed, and sleep disturbances. Three hundred twelve patients (37% female; median age = 15.0 years; evaluated median = 9 days postinjury) reported experiencing current neck or shoulder pain at initial evaluation, and 268 did not (31% female; median age = 14.7 years; evaluated median = 8 days postinjury). Neck or shoulder pain was associated with longer symptom resolution time (β = 6.38, 95% confidence interval [CI] = 2.44, 10.31; P = .002), more severe symptoms (β = 7.06, 95% CI = 4.91, 9.21; P < .001), and greater odds of missing >5 days of school (adjusted odds ratio [aOR] = 1.89, 95% CI = 1.23, 2.93; P = .004), and postinjury sleep problems (aOR = 2.20, 95% CI = 1.51, 3.21; P < .001). Experiencing neck or shoulder pain during the initial postinjury clinical evaluation was associated with worsened clinical outcomes. Clinicians may consider referral to early rehabilitation following concussion among those who report neck or shoulder pain.

Utility of a novel perceptual-motor control test for identification of sport-related concussion beyond current clinical assessments

Clinically feasible metrics, that can inform the concussion recovery decision making process by evaluating a unique domain beyond current testing domains (e.g., balance, neurocognition, symptoms, vestibular/ocular function) are still in need. The purpose of this study was to compare perceptual-motor control in adolescent athletes ≤21 days of sport-related concussion and healthy controls and evaluate the association of perceptual-motor control to the outcomes of commonly-used sport-related concussion clinical assessments. Athletes (age: 12-18 years) with sport-related concussion (n = 48) and healthy controls (n = 24) completed the Perception-Action Coupling Task (PACT), whose outcomes are mean reaction, movement, initiation, response time, and accuracy. ImPACT outcomes are verbal/visual memory scores, motor processing speed, and reaction time. Vestibular-Ocular Motor Screen (VOMS) outcomes are symptoms from: smooth pursuit, horizontal/vertical saccades, near-point of convergence, horizontal/vestibular ocular-reflex, and visual motion sensitivity. CONCUSSED demonstrated ~5% deficit in overall perceptual-motor accuracy during PACT compared to CONTROLS (p = 0.03). PACT accuracy negatively correlated with smooth pursuits(r = -0.29), and horizontal (r = -0.35)/vertical (r = -0.30) saccades. The C5.0 decision tree determined PACT accuracy was the most relevant predictor of sport-related concussion when no visual motion sensitivity symptoms were reported and Visual Memory was >66. Perceptual-motor control tests may complement current sport-related concussion assessments when neurocognition and vestibular/ocular motor system are not grossly impaired.

The effect of cognitive dual-tasks on dynamic postural sway during gait using inertial measurement units

OBJECTIVE

To investigate the influence of cognitive dual-tasks on dynamic postural sway variability, measured with a single inertial measurement unit, in healthy collegiate athletes during dual-task gait.

APPROACH

Thirty-four athletes ambulated down and back a 10-meter course. Root mean square values of postural sway acceleration were calculated for four sway-planes. Single and dual-task trial times were calculated from gait initiation to termination. Single and dual-task root mean square values were compared using Wilcoxon signed rank tests for each sway plane to determine significance. The relative difference between each sway measures and trial times for single and dual-task gait (i.e. dual-task cost was calculated). Spearman's correlation was used to analyze the association between dual-task cost of sway and trial time data.

MAIN RESULTS

During dual-task conditions, participants ambulated slower and demonstrated a significant reduction in root mean square sway in all planes of motion. The greatest decreases were in the medial-lateral (Z = -4.83, p < 0.001, ES = -0.83) and superior-inferior planes (Z = -4.93, p < 0.001, ES = -0.85). Increased trial time cost was associated with a decrease in dual-task cost of postural sway (p < 0.05).

SIGNIFICANCE

Performing a cognitive task while ambulating decreased postural sway variability in task-relevant planes of motion compared to single-task conditions. Reduced dual-task cost of sway variability during gait was associated with maintained trial times between single and dual-tasks. These data support the use of instrumented dual-task gait assessment to evaluate postural sway variability.

What they know and who they are telling: Concussion knowledge and disclosure behaviour in New Zealand adolescent rugby union players

The purpose of this study was to survey high school rugby players from a range of ethnic, geographic and socioeconomic backgrounds in New Zealand (NZ) to gain an understanding of concussion knowledge, awareness of NZ Rugby's (NZR) guidelines and attitudes towards reporting behaviours. Male and female high school rugby players (n= 416) from across NZ were surveyed. The findings indicated that 69% of players had sustained a suspected concussion, and 31% had received a medical diagnosis of concussion. 63% of players indicated they were aware of NZR's guidelines. Māori and Pasifika players were less likely to be aware of the guidelines compared to NZ European, Adjusted OR 0.5, p = 0.03. Guideline awareness was significantly higher for those from high decile schools when compared to low (Unadjusted OR 1.63, p = 0.04); however, when ethnicity and school locations were controlled for this became non-significant (Adjusted OR= 1.3, p=0.37). The coach was the key individual for the provision of concussion information and disclosure of symptoms for players. The findings of this study will inform the development and delivery of NZR's community concussion initiative and how these examined factors influence a high school player's concussion knowledge and reporting behaviour.

Development of a Peer Education Program to Improve Concussion Knowledge and Reporting in Collegiate Athletes

CONTEXT

A novel peer concussion-education program (PCEP) was developed to enhance concussion knowledge and reporting among collegiate student-athletes.

OBJECTIVE

To describe the PCEP and its development and implementation.

DESIGN

Program development consisting of a literature review, focus group, and pilot implementation.

SETTING

Athletics department at a college participating at the National Collegiate Athletic Association Division II-sanctioned competition level.

PATIENTS OR OTHER PARTICIPANTS

Fifteen student-athletes from the women's soccer and men's lacrosse teams participated in the focus group. Four peer concussion educators (PCEs) were debriefed after the pilot implementation of the PCEP with the women's soccer and men's lacrosse teams.

DATA COLLECTION AND ANALYSIS

Focus-group data were analyzed qualitatively. The PCEs were debriefed, and responses were organized into recommendation types.

RESULTS

The literature review contributed information that supported the development of the PCEP's conceptual model. Focus-group results provided information used to train the PCEs and refine the PCEP's education modules. The pilot implementation and PCE debriefing supplied information used to further revise the education modules, PCE training, and PCEP implementation procedure.

CONCLUSIONS

The PCEP was developed based on the Theory of Reasoned Action and Planned Behavior and uses a peer-mediated, cognitive-behavioral, and interdisciplinary model to enhance concussion knowledge of and reporting by collegiate student-athletes. After a focus-group discussion and pilot implementation, we revised the PCEP and its education modules and developed an online manual to facilitate broad dissemination.

Association of Time Since Injury to the First Clinic Visit With Recovery Following Concussion

Importance

Recovery after concussion varies, with adolescents taking longer (approximately 30 days) than adults. Many factors have been reported to influence recovery, including preinjury factors, perceptions about recovery, comorbid conditions, and sex. However, 1 factor that may play a role in recovery but has received little attention from researchers is the timeliness of clinical evaluation and care.

Objective

To investigate the association of time since injury with initiation of clinical care on recovery time following concussion.

Design, Setting, and Participants

This retrospective, cross-sectional study was conducted in a sports medicine clinic between August 2016 and March 2018. Eligible participants were aged 12 to 22 years and had a diagnosed, symptomatic concussion; patients were excluded if recovery data were incomplete. Participants were divided into 2 groups: those seen within 7 days of the injury (early) vs between 8 and 20 days of the injury (late). Data were analyzed between June 2019 and August 2019.

Exposures

Time from injury (concussion) to initiation of clinical care.

Main Outcomes and Measures

Recovery time; testing with the Post-Concussion Symptom Scale, Immediate Post-Concussion Assessment and Cognitive Testing, and Vestibular/Ocular Motor Screening instruments; demographic factors, medical history, and injury information.

Results

A total of 416 individuals were eligible, and 254 (61.1%) were excluded, leaving 162 (38.9%) in analyses. The early group (98 patients) and late group (64 patients) did not differ in age (mean [SD] age, early, 15.3 [1.6] years; late, 15.4 [1.6] years), number of female patients (early, 51 of 98 [52.0%]; late, 40 of 64 [62.5%]), or other demographic, medical history, or injury information. The groups also were similar on symptom severity, cognitive, ocular, and vestibular outcomes at the first clinic visit. Results from a logistical regression supported being in the late group (adjusted odds ratio, 5.8 [95% CI, 1.9-17.6]; P = .001) and visual motion sensitivity symptoms greater than 2 (adjusted odds ratio, 4.5 [95% CI, 1.1-18.0]; P = .04) as factors significantly associated with recovery time.

Conclusions and Relevance

Findings suggest that earlier initiation of clinical care is associated with faster recovery after concussion. Other factors may also influence recovery time. Further research is needed to determine the role of active rehabilitation and treatment strategies, as well as demographic factors, medical history, and injury characteristics on the current findings.

Less Than Half of Patients Recover Within 2 Weeks of Injury After a Sports-Related Mild Traumatic Brain Injury: A 2-Year Prospective Study

OBJECTIVE

To describe clinical recovery time and factors that might impact on recovery after a sports-related mild traumatic brain injury (SR-mTBI; concussion).

DESIGN

Prospective cohort study (level IV evidence).

SETTING

New Zealand Sports Concussion Clinic.

PARTICIPANTS

Eight hundred twenty-two patients presenting within 14 days of a SR-mTBI/concussion over a 2-year period.

MAIN OUTCOME MEASURES

Clinical recovery measured as number of days after injury.

INTERVENTIONS METHODS

Participants were assessed and managed using a standardized protocol consisting of relative rest followed by controlled cognitive and physical loading. A reassessment was performed 14 days after injury with initiation of an active rehabilitation program consisting of a subsymptom threshold exercise program ± cervicovestibular rehabilitation (if required) for participants who remained symptomatic. Participants were then assessed every 2 weeks until clinical recovery.

RESULTS

A total of 594 participants were eligible for analysis (mean age 20.2 ± 8.7 years, 77% males) and were grouped into 3 age cohorts: children (≤12 years), adolescents (13-18 years), and adults (≥19 years). Forty-five percent of participants showed clinical recovery within 14 days of injury, 77% by 4 weeks after injury, and 96% by 8 weeks after injury. There was no significant difference in recovery time between age groups. Prolonged recovery was more common in females (P = 0.001), participants with "concussion modifiers" (P = 0.001), and with increased time between injury and the initial appointment (P = 0.003).

CONCLUSIONS

This study challenges current perceptions that most people with a SR-mTBI (concussion) recover within 10 to 14 days and that age is a determinant of recovery rate. Active rehabilitation results in high recovery rates after SR-mTBI.

Video Analysis of Concussion Exposures in a National Collegiate Athletic Association Division I Football Team

Background:

Research into improving player safety of sport-related concussion (SRC) in American football has been an ongoing endeavor. In an attempt to better understand the incidence of SRCs in American football, research has focused on the characteristics of SRC during gameplay. Determining SRC specifics and assessing them quantitatively can help identify high-risk scenarios and predict exposure risk.

Purpose:

To identify and assess the incidence of SRCs in a National Collegiate Athletic Association football team by comparing field location, player positions, collision partners, and player cues.

Study Design:

Descriptive epidemiology study.

Methods:

We used physician sideline reports of diagnosed concussions from a Division I football team from September 2010 to December 2018. Game videos were analyzed to identify the field location where the SRC occurred, collision partner, and player behavior postconcussion. The incidence of in-game SRCs by position was also assessed. We used the “words of estimative probability” model to categorize each concussion as certain, almost certain, probable, or even on the basis of our confidence in identifying them using game film.

Results:

This study examined 44 SRCs that occurred over 9 seasons. The SRC incidence was significantly higher in the middle defense (5-20 yards from the line of scrimmage) compared with all other field locations (relative risk, 2.46; 95% CI, 1.14-5.29; P < .05). In-game collision partners were most commonly defensive backs. The most common player cue was a hand to helmet/face mask. The positions with the highest SRC incidence by athlete-exposure, game position, and position play belonged to the defensive backs, wide receivers, and running backs.

Conclusion:

The middle defense had a significantly higher incidence of SRCs than all other field locations. We pose a new method to categorize concussions during video analysis by using words of estimative probability. Knowledge of SRC gameplay characteristics can potentially guide the medical staff and medical observer to better identify them.

Quantitative and qualitative analysis of head and body impacts in American 7v7 non-tackle football

Objectives

Non-tackle American football is growing in popularity, and it has been proposed as a safer alternative for young athletes interested in American football. Little is known about the nature of head contact in the sport, which is necessary to inform the extent to which protective headgear is warranted. The objective of this study was to identify the location, types and frequency of head and body contacts in competitive 7v7 non-tackle American football.

Methods

Video analysis was used to document the type, frequency and mechanism of contacts across a series of under 12, under 14 and high school non-tackle tournament games. A subset of impacts was quantitatively analysed via 3-D model-based image matching to calculate the preimpact and postimpact speed of players’ heads and the change in resultant translational and rotational velocities.

Results

The incidence rate of head contact was found to be low (3.5 contacts per 1000 athlete-plays). Seventy-five per cent of head contacts were caused by a head-to-ground impact. No head-to-head contacts were identified. Most contacts occurred to the rear upper (occiput) or side upper (temporal/parietal) regions. Head-to-ground impact was associated with a maximum preimpact velocity of 5.9±2.2 m/s and a change in velocity of 3.0±1.1 m/s.

Conclusion

Non-tackle football appears to represent a lower contact alternative to tackle football. The distribution of head impact locations, mechanisms and energies found in the present study is different than what has been previously reported for tackle football. The existing tackle football standards are not appropriate to be applied to the sport of non-tackle football, and sport-specific head protection and headgear certification standards must be determined.

Recent Trends in Youth Concussions: A Brief Report

Objectives

Concussions and mild traumatic brain injuries are important medical issues, particularly among youth as the long-term health consequences of these injuries can become increasingly problematic. The purpose of this study was to examine recent trends in diagnosed concussions among pediatric patients in a large health care system.

Methods

This was a retrospective, population-based epidemiology study design that queried all patient files (pediatrics included) using electronic medical health records and further stratified patients based on type of concussion, age, sex, and year from 2013 to 2018.

Results

Electronic health records from a cohort of 8 832 419 (n_males = 4 246 492; n_females = 4 585 931) patient visits were assessed for concussion diagnosis and filtered for those whose concussive event led to a loss of consciousness (LOC) or not (nLOC). Of these patients, 12 068 were diagnosed with a concussion (LOC = 3 699; nLOC = 8 369) with an overall incidence rate of 1.37 concussions per 1000 patients. Overall, the number of patients diagnosed with a concussion increased by 5063 (LOC = 1351; nLOC = 3712) from 2013 to 2018. Males and females presented with similar rates of concussions 5919 (49.05%) and 6149 concussions (50.95%), respectively. Of total diagnosed concussions, 4972 (LOC = 815; nLOC = 4157) were under the age of 18 and represented 41.2% of all diagnosed concussions with an incidence rate of 6.79 per 1000 patients.

Conclusion

The number of concussions diagnosed appear to be on the rise with the largest number of concussions being diagnosed in those under the age of 18. Future studies should seek to determine primary causality and the long-term health implications of concussions with or without LOC.

In-clinic event related potentials after sports concussion: A 4-year study

PURPOSE

Electrophysiological event-related potentials (ERP's) have been reported to change after concussion. The objective of this study is to use a simple 2-tone auditory P300 ERP in routine clinical settings to measure changes from baseline after concussion and to determine if these changes persist at return to play when other standard measures have normalized.

METHODS

Three-hundred sixty-four (364) student athletes, aged 17-23 years, participating in contact sports were tracked over consecutive years. In this blinded study P300, plus physical reaction times and Trail Making tests, were collected alongside standard clinical evaluations. Changes in these measures after concussion were compared to clinical outcomes over various stages of post-injury recovery.

RESULTS

Concussed players experienced significant reaction time and/or P300 amplitude changes compared to pre-concussion baseline measurements (p< 0.005). P300 changes persisted in 38% of the players after standard measures, including reaction times, had cleared. Many of those players slow to normalize were part of the sub-concussive symptom group and/or appeared more prone to repeat concussions.

CONCLUSION

These data suggest significant P300 amplitude changes after concussion that are quantifiable and consistent. These changes often normalized slower than other standard assessments. More data are needed to determine if slow normalization relates to sub-concussive or repeated events.

Combined Optokinetic Treatment and Vestibular Rehabilitation to Reduce Visually Induced Dizziness in a Professional Ice Hockey Player After Concussion: A Clinical Case

Background: The appropriate detection and therapy of concussion symptoms are of great importance to avoid long-term impairment and absence from pre-concussive activities, such as sport, school or work. Post-traumatic headache and dizziness are known as risk factors of persistent symptoms after a concussion. Dizziness has even been classified as a predictor for symptom persistence. One type of dizziness, which has never been considered is visually induced dizziness (VID) often develops as a consequence of vestibular impairment. This manuscript presents the clinical case of a 25-year-old male, professional ice hockey player, whereby a therapeutic approach to VID after concussion is demonstrated.

Case: A detailed interdisciplinary clinical and laboratory-assisted neurological, neurovestibular and ocular-motor examination was performed 20 days post-concussion, which indicated VID symptoms. Thus, the player qualified for a 5-day combined vestibular, balance and optokinetic therapy, which aimed to reduce the player's increased sensitivity to visual information. Each treatment day consisted of two sessions: vestibular/ocular-motor training and exposure to optokinetic stimuli combined with postural control exercises. The optokinetic stimulus was delivered in the form of a rotating disk. VID symptoms were recorded daily via posturography and a visual analog scale prior to the optokinetic sessions. The player improved over the course of each treatment day and was able to return to ice hockey 15 days after the final treatment session. Three months later the player reported no symptoms in the follow up questionnaire.

Conclusion: The combination of vestibular, balance and optokinetic therapy led to remission of VID symptoms in a professional ice hockey player after multiple concussions, within a short time frame after his last concussion. Thus, this case study highlights the significant benefit of treating post-concussive VID symptoms utilizing a multi-modal approach.

The Epidemiology of Sport-Related Concussion: What the Rehabilitation Clinician Needs to Know

Sport-related concussion is common in full-contact and collision sports. Epidemiology studies use different types of surveillance systems and concussion definitions. Concussion incidence rates vary across age, sex, sport, and level of competition. Incidence rates are increasing, likely due to higher rates of reporting following improved knowledge and increased regulations. In this review, we summarize 7 key concepts related to concussion epidemiology: concussion definition, changes in concussion knowledge, reliability and accuracy of injury surveillance systems, conservative management and return to play, reliability of self-report, incidence of concussion across levels of play, and understanding the behaviors of players, coaches, and medical personnel from a multidisciplinary management perspective. J Orthop Sports Phys Ther 2019;49(11):768-778. doi:10.2519/jospt.2019.9105.

Relationship Between the King-Devick Test and Commonly Used Concussion Tests at Baseline

CONTEXT

Comprehensive assessments are recommended to evaluate sport-related concussion (SRC). The degree to which the King-Devick (KD) test adds novel information to an SRC evaluation is unknown.

OBJECTIVE

To describe relationships at baseline among the KD and other SRC assessments and explore whether the KD provides unique information to a multimodal baseline concussion assessment.

DESIGN

Cross-sectional study.

SETTING

Five National Collegiate Athletic Association institutions participating in the Concussion Assessment, Research and Education (CARE) Consortium.

PATIENTS OR OTHER PARTICIPANTS

National Collegiate Athletic Association student-athletes (N = 2258, age = 20 ± 1.5 years, 53.0% male, 68.9% white) in 11 men's and 13 women's sports.

MAIN OUTCOME MEASURE(S)

Participants completed baseline assessments on the KD and (1) the Symptom Inventory of the Sport Concussion Assessment Tool-3rd edition, (2) the Brief Symptom Inventory-18, (3) the Balance Error Scoring System, (4) the Standardized Assessment of Concussion (SAC), (5) the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test battery, and (6) the Vestibular/Ocular Motor Screening tool during their first year in CARE. Correlation coefficients between the KD and the 6 other concussion assessments in isolation were determined. Assessments with ρ magnitude >0.1 were included in a multivariate linear regression analysis to evaluate their relative association with the KD.

RESULTS

Scores for SAC concentration, ImPACT visual motor speed, and ImPACT reaction time were correlated with the KD (ρ = -0.216, -0.276, and 0.164, respectively) and were thus included in the regression model, which explained 16.8% of the variance in baseline KD time (P < .001, Cohen f² = 0.20). Better SAC concentration score (β = -.174, P < .001), ImPACT visual motor speed (β = -.205, P < .001), and ImPACT reaction time (β = .056, P = .020) were associated with faster baseline KD performance, but the effect sizes were small.

CONCLUSIONS

Better performance on cognitive measures involving concentration, visual motor speed, and reaction time was weakly associated with better baseline KD performance. Symptoms, psychological distress, balance, and vestibular-oculomotor provocation were unrelated to KD performance at baseline. The findings indicate limited overlap at baseline among the CARE SRC assessments and the KD.