Influence of sleep symptoms on recovery from concussion in collegiate athletes: a LIMBIC MATARS consortium investigation

OBJECTIVE

Changes in sleep quality and quantity are commonly endorsed by individuals following a concussion. Limited data exists examining the role of sleep disturbances within 72 hours, and throughout recovery, from concussion. The objective of this study was to determine if the number of days to symptom resolution varied between collegiate athletes with or without sleep-related symptoms following a concussion.

DESIGN

Retrospective chart review.

METHODS

Collegiate athletes (n = 539) who were diagnosed with a concussion between the 2015-2020 sport seasons participated in this retrospective chart review. Participants were divided into groups based on the presence or absence of sleep symptoms within 72 hours of a diagnosed concussion. A Mann-Whitney U test was used to compare days to symptom resolution between groups with α = 0.05.

RESULTS

Of the 539 participants, 250 (46.3%) reported sleep-related symptoms. Participants with sleep-related symptoms took significantly longer (U = 30656, p = 0.002) to report symptom resolution at rest (median [full range] = 8.00[0-423]) as compared to participants who did not report sleep-related symptoms (6.00[0-243] days).

CONCLUSION

Collegiate athletes that report sleep-related symptoms immediately following concussion (<72 hours) were observed to take, on median, two days longer to achieve symptom resolution at rest when compared to athletes who did not endorse the same symptoms.

Academic adjustments and concussion recoveries in NCAA student-athletes: a LIMBIC MATARS investigation

OBJECTIVE

The aim of this study was to investigate the association between academic adjustments and recovery from sport-related concussions (SRCs) in collegiate athletes.

MATERIALS AND METHODS

A retrospective medical chart review was performed between the 2015-2016 and 2019-2020 sport seasons at 11 Long-term Impact of Military-relevant Brain Injury Consortium Military and Tactical Athlete Research Study (LIMBIC MATARS) sites. Days between injury and symptom resolution, and injury and return to sport (dependent variables) for collegiate athletes who did or did not receive academic adjustments (independent variable) were analyzed using Mann-Whitney U tests.

RESULTS

The number of days between date of injury and symptom-resolution between those who did (median = 9 [interquartile range = 5,16]) and did not have (7[3,12]) academic adjustments were statistically different (z=-2.76, p < 0.01, r=-0.17). However, no differences were observed between days to return to sport among those who did (14[10,22]) and did not (13[8,20]) receive assigned academic adjustments (z= -1.66, p = 0.10, r= -.10).

CONCLUSIONS

Recovery trajectories were similar between athletes diagnosed with a SRC who did or did not receive academic adjustments.. Our findings suggest academic adjustments supported recovery for those who needed academic adjustments. Clinicians and healthcare professionals should assist and support collegiate athletes after SRCs on an individual basis, including academic adjustments when appropriate based on patient presentation.

The Influence of Race on Time to Symptom Resolution Following Sport Concussion in Collegiate Athletes

CONTEXT

Race has been shown to influence computerized neurocognitive test scores, motor function test scores, and reported symptomology following sport-related concussion (SRC). However, the effect race may have on recovery time following SRC remains unknown. The objective of this study was to determine the influence of race on days until symptom free from SRC in NCAA Division 1 collegiate athletes.

DESIGN

Prospective cohort study.

METHODS

Participants were Black (n = 53 [28% female]) and White (n = 150 [43.3% female]) who were on average 19.0 (1.21) and 20.2 (1.3) years of age, respectively. Data were collected from the 2015-2016 to 2020-2021 collegiate sport seasons. Participants were evaluated before and after an SRC at empirically derived time points. The primary outcome measure was time until symptom free (days). Additional outcomes included baseline and postinjury Immediate Postconcussion Assessment and Cognitive Test and Sensory Organization Test (SOT) scores. A Mann-Whitney U test compared days to symptom free between groups. Immediate Postconcussion Assessment and Cognitive Test and SOT outcome scores were analyzed using a 2 (group) × 2 (time) analysis of variance.

RESULTS

White participants had a longer median recovery time (9 d) to symptom free compared with Black participants (6 d [P = .04]). Statistically significant differences were observed between Black 87.3 (9.84) and White 90.4 (8.30) groups for Immediate Postconcussion Assessment and Cognitive Test's verbal memory composite score (P = .03). Postinjury, White participants scored significantly higher 44.5 (5.63) on visual motor speed compared with Black participants (42.4 (5.90) [P = .02]). Within-group SOT differences between baseline and postinjury testing were observed in both groups (all P < .001).

CONCLUSIONS

Black collegiate athletes achieved symptom resolution sooner than White athletes. We did not explore underlying sociocultural factors such as socioeconomic status or previous concussion education, which may have influenced our results. Future studies should explore factors that may contextualize these findings.

Exploring the relationship between contraceptive medication use and concussion recovery in female collegiate athletes: a LIMBIC MATARS consortium investigation

OBJECTIVE

While recovery from concussion is variable, women are more likely to report symptoms, experience worse outcomes, and have longer recovery trajectories following concussion than men. Preliminary data suggest that hormonal fluctuations, specifically progesterone, may be associated with this variability. This study aimed to understand the effect of contraceptive medication on concussion recovery.

METHODS

A retrospective chart review using consensus-based common data elements was conducted at 11 NCAA institutions as part of the LIMBIC MATARS consortium. Participants included female collegiate athletes diagnosed with a concussion who did (n = 117) or did not report (n = 339) contraceptive medication use. Number of days between diagnosis and symptom resolution were compared using Mann-Whitney U tests. Self-reported diagnosis of attention deficit hyperactivity disorder, concussion history, anxiety, and depression was compared using Chi-squared tests.

RESULTS

The proportions of participants who did or did not take contraceptive medication were similar across covariates. Female athletes regardless of contraceptive medication use recovered similarly following a concussion.

CONCLUSIONS

Our findings suggest that contraceptive medication use did not significantly impact concussion recovery. Future prospective investigations should examine documentation practices and operationalize terminology for hormonal contraceptive medication to better understand their role on recovery from sport-related concussion in female collegiate athletes.

Concussion diagnosis and recovery in relation to collegiate athletic department classification: a LIMBIC MATARS consortium investigation

PURPOSE

We investigated time to reach concussion diagnosis and recovery milestones in collegiate athletes relative to their schools' National Collegiate Athletic Association (NCAA) classification.

METHODS

We retrospectively examined 849 (43.1% female) concussion cases from 11 NCAA institutions (Division I Power 5 [n = 4], Division I Non-Power 5 [n = 4], and Division II/III [n = 3]) from the 2015-16 to 2019-20 athletic seasons. Our primary outcome measures were days to reach specific clinical milestones following concussion.

RESULTS

Median (IQR) time from injury to diagnosis was significantly longer at Division II/III institutions (1 [0-4] days) compared to Division I Power 5 (0 [0-1] days) and Division I Non-Power 5 (0 [0-1] days) institutions (p < 0.001). Likewise, Division II/III athletes (15 [11-22] days) took significantly longer to return to sport after concussion than Division I Power 5 (10 [7-16] days) and Division I Non-Power 5 (11 [7-18.5] days) athletes (p < 0.001).

CONCLUSION

Division II/III athletes had delayed concussion diagnoses and return to sport timelines compared to Division I athletes. Our results suggest that differences in sports medicine resources across NCAA divisions may influence injury recognition and recovery in collegiate athletes with concussion.

Placing the keystone: the LIMBIC Military and Tactical Athlete Research Study

OBJECTIVE

The LIMBIC Military and Tactical Athletic Research Study (MATARS) framework was established to confirm and extend understanding of concussion with initial studies driven by clinical data collected between 2015 and 2020 in a collegiate sports setting. The LIMBIC MATARS framework will be leveraged to apply gold-standard and innovative research designs to advance the science of concussion. This manuscript provides the background, methodology, and initial demographic data associated with the LIMBIC MATARS.

METHODS

Consensus-based common data elements were used to conduct a retrospective chart review, specific to collegiate athletes diagnosed with concussions between 2015 and 2020 at 11 universities.

RESULTS

A final sample of 1,311 (47.8% female) concussions were diagnosed during the five-year study period from athletes participating in a variety of National Collegiate Athlete Association (NCAA) sports. The LIMBIC MATARS demographic data, align with the NCAA and other pioneering multi-site concussion-related studies in terms of biological sex, race and ethnicity, and sport participation.

CONCLUSION

This pragmatic, methodological approach was used to address several a priori hypotheses related to concussion, align with other multi-site studies of concussion, and establish a consortium for future investigations.

Physical activity and recovery following concussion in collegiate athletes: a LIMBIC MATARS Consortium Investigation

OBJECTIVE

To investigate whether routine daily activities (RDA), non-prescribed exercise (Non-ERx), or prescribed exercise (ERx) were associated with recovery from sport-related concussion (SRC) in collegiate athletes.

MATERIALS AND METHODS

Data for this cross-sectional, retrospective chart review of collegiate athletes diagnosed with SRC (n = 285[39.6% female], age = 19.5 ± 1.4 years) were collected during the 2015-16 to 2019-20 athletic seasons. The independent variable was group (RDA, Non-ERx, ERx). Dependent variables included days from date of diagnosis to symptom resolution (Dx-SR) and SR to return to sport (SR-RTS).

RESULTS

Those in the Non-ERx group took nearly 1.3 times longer to achieve SR (IRR = 1.28, 95% CI: 1.11, 1.46) and, 1.8 times longer for RTS (IRR = 1.82, 95% CI: 1.11, 2.71) when compared to those in the RDA group. No other comparisons were significant.

CONCLUSION

Collegiate athletes in the Non-ERx group took approximately 1 week longer to achieve SR as compared to the RDA and ERx groups. Our findings suggest that if exercise is recommended following SRC, it must be clearly and specifically prescribed. If exercise parameters cannot be prescribed, or monitored, RDA appear to be similarly beneficial during recovery for collegiate athletes with concussion.

Access to athletic trainers and sex as modifiers of time to reach clinical milestones after sport-related concussion in collegiate athletes

OBJECTIVE

Investigate whether an athlete's biological sex and exposure to a dedicated athletic trainer (AT) were related to clinical milestones after a sports-related concussion (SRC).

DESIGN

Retrospective chart review.

METHODS

Medical charts of collegiate athletes (n = 196 [70.9% female]) diagnosed with SRC were reviewed to extract: biological sex, dedicated AT exposure for their sport (yes/no), and time (days) to reaching clinical milestones (diagnosis, symptom resolution, unrestricted return to sport [RTS]). Mann-Whitney U tests were used to determine whether time to clinical milestones differed by sex, AT exposure, or their interaction. Proportions of same-day diagnoses and times to diagnosis, symptom resolution, and unrestricted RTS were evaluated with chi-squared and spearman's rank correlations, respectively.

RESULTS

There were no significant differences in times to reaching any clinical milestone by sex, AT exposure, or their interaction (ps > 0.05). Forty-three percent of participants were diagnosed on the day of their SRC. This did not differ by sex or AT exposure (ps > 0.29). Longer times to SRC diagnosis were associated with more days to symptom resolution (ρ = 0.236, p = 0.001) and unrestricted RTS (ρ = 0.223, p < 0.001).

CONCLUSIONS

Athlete sex and AT exposure were not associated with times to reach any clinical milestone; however, delayed diagnosis was associated with longer times to reach clinical recovery.

Sport Type and Risk of Subsequent Injury in Collegiate Athletes Following Concussion: a LIMBIC MATARS Consortium Investigation

OBJECTIVE

To investigate the association between sport type (collision, contact, non-contact) and subsequent injury risk following concussion in collegiate athletes.

MATERIALS AND METHODS

This retrospective chart review of 248 collegiate athletes with diagnosed concussions (age: 20.0 ± 1.4 years; height: 179.6 ± 10.9 cm; mass: 79.0 ± 13.6 kg, 63% male) from NCAA athletic programs (n = 11) occurred between the 2015-2020 athletic seasons. Acute injuries that occurred within six months following concussion were evaluated. Subsequent injuries were grouped by lower extremity, upper extremity, trunk, or concussion. The independent variable was sport type: collision, contact, non-contact. A Cox proportional hazard model was used to assess the risk of subsequent injury between sport types.

RESULTS

Approximately 28% (70/248) of athletes sustained a subsequent acute injury within six months post-concussion. Collision sport athletes had a significantly higher risk of sustaining any injury (HR: 0.41, p < 0.001, 95% CI: 0.28, 0.62), lower extremity (HR: 0.55, p = 0.04, 95% CI: 0.32, 0.97), and upper extremity (HR: 0.41, p = 0.01, 95% CI: 0.20, 0.81) injuries following concussion. No differences between sport types were observed for other injuries.

CONCLUSION

Collision sport athletes had a higher rate of any subsequent injury, lower, and upper extremity injuries following concussion. Future research should focus on sport-specific secondary injury prevention efforts.

The Effect of Exercise on a Novel Dual-Task Assessment for Sport Concussion

PURPOSE

This study aimed to determine the effect of exercise on cognitive and motor performance and the subsequent test-retest reliability of a novel dual-task (DT) assessment in nonconcussed college students.

METHODS

Sixty nonconcussed college students (53.3% female) with an average age (±SD) of 20.5 ± 1.34 yr, height of 171.7 ± 9.33 cm, and mass of 69.3 ± 12.23 kg were included in the study. Participants were assigned to an exercise ( n = 30) or rest ( n = 30) intervention group and completed two study visits that were separated by a 2-wk test-retest interval. At each visit, participants completed a novel DT assessment that consisted of the concurrent administration of the Standardized Assessment of Concussion (SAC) and tandem gait (TG) before the exercise or rest intervention. After the DT assessment at the first visit, participants in the exercise group performed moderate-intensity exercise, whereas the rest group sat quietly for 30 min. After the intervention, both groups were readministered the DT assessment. At the second visit, the same procedures were followed, except that each group was administered the opposite intervention (e.g., the exercise group completed the rest intervention). A composite TG (cTG) score was calculated by summing the average time to complete the TG pattern during each SAC domain (immediate memory, digits backwards, months in reverse order, delayed recall). An ANCOVA was conducted to assess postintervention differences while controlling for preintervention performance. Test-retest reliability was assessed using intraclass correlation coefficients (ICC 3,2 ) with 95% confidence intervals, with all analyses performed with α = 0.05.

RESULTS

SAC and cTG performance was similar ( P values > 0.05) from preintervention to postintervention for the rest or exercise protocols. Good (rest: ICC = 0.77 (0.62-0.87); exercise: ICC = 0.84 (0.73-0.90)) and excellent (rest: ICC = 0.97 (0.94-0.98); exercise: ICC = 0.93 (0.88-0.96)) test-retest reliabilities were observed for the SAC composite score and cTG score, respectively.

CONCLUSIONS

Our DT assessment was robust to the influence of moderate-intensity exercise and demonstrated good-to-excellent test-retest reliability in a healthy collegiate sample.

Psychometric Properties of Computerized Cognitive Tools and Standard Neuropsychological Tests Used to Assess Sport Concussion: A Systematic Review

Athletic programs are more frequently turning to computerized cognitive tools in order to increase efficiencies in concussion assessment. However, assessment using a traditional neuropsychological test battery may provide a more comprehensive and individualized evaluation. Our goal was to inform sport clinicians of the best practices for concussion assessment through a systematic literature review describing the psychometric properties of standard neuropsychological tests and computerized tools. We conducted our search in relevant databases including Ovid Medline, Web of Science, PsycINFO, and Scopus. Journal articles were included if they evaluated psychometric properties (e.g., reliability, sensitivity) of a cognitive assessment within pure athlete samples (up to 30 days post-injury). Searches yielded 4,758 unique results. Ultimately, 103 articles met inclusion criteria, all of which focused on adolescent or young adult participants. Test-retest reliability estimates ranged from .14 to .93 for computerized tools and .02 to .95 for standard neuropsychological tests, with strongest correlations on processing speed tasks for both modalities, although processing speed tasks were most susceptible to practice effects. Reliability was improved with a 2-factor model (processing speed and memory) and by aggregating multiple baseline exams, yet remained below acceptable limits for some studies. Sensitivity to decreased cognitive performance within 72 h of injury ranged from 45%-93% for computerized tools and 18%-80% for standard neuropsychological test batteries. The method for classifying cognitive decline (normative comparison, reliable change indices, regression-based methods) affected sensitivity estimates. Combining computerized tools and standard neuropsychological tests with the strongest psychometric performance provides the greatest value in clinical assessment. To this end, future studies should evaluate the efficacy of hybrid test batteries comprised of top-performing measures from both modalities.

An Absence of Persistent Postural Stability Deficits Following a Sport Concussion in Collegiate Athletes

OBJECTIVE

The purpose of our study was to determine whether persistent postural stability deficits exist in athletes following sport concussion (SC) in comparison with preinjury (baseline) values using Sample Entropy (SampEn).

SETTING

Sports medicine clinic.

PATIENTS OR OTHER PARTICIPANTS

Participants consisted of 71 collegiate athletes (44 male, 27 female) with an average age of 19.9 ± 0.96 years who had a history of 1 concussion that occurred during their time as a collegiate athlete.

DESIGN

In our prospective, cohort design participants completed the Sensory Organization Test (SOT) at baseline, upon reporting symptom-free following a diagnosed SC, and upon establishing a new baseline prior to the start of the subsequent sport season.

MAIN OUTCOME MEASURES

The SOT's condition scores were calculated and analyzed in alignment with the manufacturer's instructions. SampEn was calculated in the anterior-posterior (AP) and medial-lateral (ML) directions from the center-of-pressure oscillations over the 20-second time series for each SOT condition. The SOT and SampEn outcome scores for each condition were analyzed with repeated-measures analyses of variance.

RESULTS

Significant main effects were observed for the SOT's conditions 3 ( F1.6, 114.8 = 7.83, P = .001, η2 = 0.10 [0.02-0.20]), 5 ( F1.8, 126.8 = 11.53, P < .001, η2 = 0.14 [0.04-0.25]), and 6 ( F1.9, 134.5 = 25.11, P < .001, η2 = 0.26 [0.14-0.37]), with significant improvements across time. Significant main effects were also observed for SampEn in the AP direction for conditions 3 ( F2, 140 = 7.59, P = .001, η2 = 0.10 [0.02-0.19]) and 6 ( F2, 140 = 6.22, P = .003, η2 = 0.08 [0.011-0.170]), with significant improvements across time.

CONCLUSIONS

Following a diagnosed SC, our results suggest that collegiate athletes returned if not exceeded baseline values at the symptom-free and new baseline assessments. The application of linear and nonlinear measures of postural stability following a SC yielded similar outcomes in conjunction with a baseline assessment. Our findings support the clinical utility of the baseline SC assessment when evaluating persisting balance deficits when using linear or nonlinear measures.

Racial identity and concussion diagnosis and recovery trajectories in collegiate athletes: a LIMBIC MATARS investigation

OBJECTIVE

To determine if there were concussion diagnosis and recovery disparities between collegiate athletes with Black and White racial identities.

DESIGN

Retrospective cohort study.

METHODS

Concussion information was extracted from NCAA athlete medical files at LIMBIC MATARS member institutions from the 2015-16' to 2019-20' academic years. A total of 410 concussions from 9 institutions were included that provided all independent (i.e. racial identity of Black or White) and dependent variable information (i.e. dates of injury, diagnosis, symptom resolution, and return to sport) that were analyzed using Mann-Whitney U tests. The sample consisted of 114 (27.8%) concussions sustained by Black athletes and 296 (72.1%) sustained by White athletes.

RESULTS

The overall sample had a median of 0 days between injury occurrence to diagnosis, 7 days to symptom resolution, and 12 days to return to sport. No significant timing differences were observed for concussion diagnosis (p = .14), symptom resolution (p = .39), or return to sport (p = 0.58) between collegiate athletes with Black versus White racial identities.

CONCLUSIONS

These findings may reflect equitable access to onsite sports medicine healthcare resources that facilitate concussion management in the collegiate sport setting. Future work should explore these associations with a larger and more diverse sample of collegiate athletes.

Concussion: Beyond the Cascade

Sport concussion affects millions of athletes each year at all levels of sport. Increasing evidence demonstrates clinical and physiological recovery are becoming more divergent definitions, as evidenced by several studies examining blood-based biomarkers of inflammation and imaging studies of the central nervous system (CNS). Recent studies have shown elevated microglial activation in the CNS in active and retired American football players, as well as in active collegiate athletes who were diagnosed with a concussion and returned to sport. These data are supportive of discordance in clinical symptomology and the inflammatory response in the CNS upon symptom resolution. In this review, we will summarize recent advances in the understanding of the inflammatory response associated with sport concussion and broader mild traumatic brain injury, as well as provide an outlook for important research questions to better align clinical and physiological recovery.

Microglial activation persists beyond clinical recovery following sport concussion in collegiate athletes

Introduction

In concussion, clinical and physiological recovery are increasingly recognized as diverging definitions. This study investigated whether central microglial activation persisted in participants with concussion after receiving an unrestricted return-to-play (uRTP) designation using [18F]DPA-714 PET, an in vivo marker of microglia activation.

Methods

Eight (5 M, 3 F) current athletes with concussion (Group 1) and 10 (5 M, 5 F) healthy collegiate students (Group 2) were enrolled. Group 1 completed a pre-injury (Visit1) screen, follow-up Visit2 within 24 h of a concussion diagnosis, and Visit3 at the time of uRTP. Healthy participants only completed assessments at Visit2 and Visit3. At Visit2, all participants completed a multidimensional battery of tests followed by a blood draw to determine genotype and study inclusion. At Visit3, participants completed a clinical battery of tests, brain MRI, and brain PET; no imaging tests were performed outside of Visit3.

Results

For Group 1, significant differences were observed between Visits 1 and 2 (p < 0.05) in ImPACT, SCAT5 and SOT performance, but not between Visit1 and Visit3 for standard clinical measures (all p > 0.05), reflecting clinical recovery. Despite achieving clinical recovery, PET imaging at Visit3 revealed consistently higher [18F]DPA-714 tracer distribution volume (VT) of Group 1 compared to Group 2 in 10 brain regions (p < 0.001) analyzed from 164 regions of the whole brain, most notably within the limbic system, dorsal striatum, and medial temporal lobe. No notable differences were observed between clinical measures and VT between Group 1 and Group 2 at Visit3.

Discussion

Our study is the first to demonstrate persisting microglial activation in active collegiate athletes who were diagnosed with a sport concussion and cleared for uRTP based on a clinical recovery.

Concussion Assessment and Management Practices Among Irish and Canadian Athletic Therapists: An International Perspective

CONTEXT

Certified athletic therapists in Ireland and Canada serve essential concussion assessment and management roles, but their healthcare practices and concussion knowledge are unestablished.

OBJECTIVE

To examine Irish and Canadian athletic therapist cohorts: 1) concussion knowledge, 2) current concussion assessment and management techniques across all job settings, and 3) concussion assessment and management practices associations with years of clinical experience and highest degree attained.

DESIGN

Cross-sectional cohort.

SETTING

Online survey.

PATIENTS OR OTHER PARTICIPANTS

Licensed Irish (49.7%;n=91/183) and Canadian (10.1%;n=211/2,090) athletic therapists.

MAIN OUTCOME MEASURES

Athletic therapists completed an online survey assessing their demographics, concussion knowledge (symptom recognition, patient-clinician scenarios), annual concussions assessed, and assessment and return-to-play (RTP) measures using a modified, previously validated survey. Symptom recognition consisted of 20 (8 true, 12 false) signs and symptoms recognition questions scored as total correct. Descriptive statistics and odds ratios (OR) were used to examine survey responses where appropriate.

RESULTS

Irish (86.8%;n=46/53) and Canadian (93.4%;n=155/166) athletic therapists indicated RTP guidelines as the most common method for determining RTP. Symptom recognition was 72.8±17.0% among Irish and 76.6±17.0% among Canadian athletic therapists. Irish (91.2%;n=52/57) and Canadian (95.3%;n=161/178) athletic therapists reported standardized sideline assessments as the most common concussion assessment method. Irish and Canadian athletic therapists' two-domain (Irish:38.6%[n=22/57]; Canadian:73.6%[n=131/178]) and three-domain (Irish:3.5%[n=2/57]; Canadian:19.7%[n=35/178]) minimum assessments (i.e. symptoms, balance, and/or neurocognitive) were not associated with education or clinical experience (p≥0.068), except for Canadian athletic therapists with Master's degrees having greater odds of completing two-domain assessments at initial evaluation than those with Bachelor's degrees (OR[95%CI]=1.8[1.41-1.95]).

CONCLUSIONS

Irish and Canadian athletic therapists demonstrated similar concussion knowledge to prior research; however, the majority did not fully adhere to international consensus concussion assessment guidelines as evidenced by low two- and three- domain assessment use. Athletic therapists should aim to implement multidimensional concussion assessments to ensure optimal healthcare practices and patient safety.

Reevaluating clinical assessment outcomes after unrestricted return to play following sport-related concussion

PRIMARY OBJECTIVE

The objective of this study was to examine neurocognition, postural control, and symptomology at multiple timepoints following concussion. We hypothesized that collegiate athletes would perform similar to or better than their baseline in terms of each outcome at both timepoints.

RESEARCH DESIGN

This was a retrospective study of 71 collegiate athletes (18.3 ± 0.89 years old; 182.2 ± 10.05 cm; 84.2 ± 20.07 kg) to observe changes in outcomes from a previously established clinical protocol.

METHODS AND PROCEDURES

Participants were administered ImPACT™, the Sensory Organization Test (SOT), and the revised head injury scale (HIS-r) prior to their seasons (baseline); upon reporting symptom-free following concussion (post-injury); and approximately 8-months after return-to-play to establish a new baseline.

MAIN OUTCOMES AND RESULTS

There were no changes in ImPACT scores or HIS-r reporting over time. ImPACT total symptom score (TSS) decreased over time (p = .002, η_p² = 0.08). Significant main effects occurred for the SOT equilibrium score (p < .01, η_p² = 0.34) and Vestibular sensory ratio (p < .001, η_p² = 0.22).

CONCLUSIONS

Our data suggest no decline in neurocognition, balance, or symptom burden approximately eight months post-injury. As clinicians continue to explore "best practices" for concussion management and potential long-term implications of these injuries it is important to monitor outcome measures longitudinally.

Mood, Psychological, and Behavioral Factors of Health-Related Quality of Life Throughout Recovery From Sport Concussion

OBJECTIVE

To measure alterations in mood, psychological, and behavioral factors in collegiate athletes throughout recovery from sport concussion (SC) compared with matched controls.

SETTING

University research laboratory.

PARTICIPANTS

Twenty (55% female) division I collegiate athletes with SC (19.3 ± 1.08 years old, 1.77 ± 0.11 m, 79.6 ± 23.37 kg) and 20 (55% female) uninjured matched controls (20.8 ± 2.17 years old, 1.77 ± 0.10 m, 81.9 ± 23.45 kg).

DESIGN

Longitudinal case control.

MAIN MEASURES

Self-reported concussion-related symptoms, anxiety, resilience, stigma, sleep disturbance, fatigue, and appetite were assessed at 3 time points in the SC group: T1 (≤72 hours of SC), T2 (7 days after T1), and TF (after symptom resolution). Control participants were evaluated at similar intervals. Group and group-by-sex differences were assessed using repeated-measures analyses of variance. Post hoc analyses were performed with Tukey's honestly significant difference (HSD) and paired-sample t tests.

RESULTS

The SC group had greater sleep disturbance than controls at T1 (P = .001; d = 1.21) and endorsed greater stigma at all time points (P ≤ .03; d ≥ 0.80). Stigma (F(2) = 3.68; P = 0.03; η2p = 0.12), sleep disturbance (F(2) = 5.27; P = .008; η2p = 0.15), and fatigue (F(2) = 3.46; P = .04; η2p = 0.11) improved throughout recovery in those with SC only. No differences were observed between males and females (P > .05).

CONCLUSION

Sleep disturbance and stigma were negatively affected by SC, highlighting potential areas for clinical interventions to maximize recovery in males and females.

On-Field Performance of an Instrumented Mouthguard for Detecting Head Impacts in American Football

Wearable sensors that accurately record head impacts experienced by athletes during play can enable a wide range of potential applications including equipment improvements, player education, and rule changes. One challenge for wearable systems is their ability to discriminate head impacts from recorded spurious signals. This study describes the development and evaluation of a head impact detection system consisting of a mouthguard sensor and machine learning model for distinguishing head impacts from spurious events in football games. Twenty-one collegiate football athletes participating in 11 games during the 2018 and 2019 seasons wore a custom-fit mouthguard instrumented with linear and angular accelerometers to collect kinematic data. Video was reviewed to classify sensor events, collected from instrumented players that sustained head impacts, as head impacts or spurious events. Data from 2018 games were used to train the ML model to classify head impacts using kinematic data features (127 head impacts; 305 non-head impacts). Performance of the mouthguard sensor and ML model were evaluated using an independent test dataset of 3 games from 2019 (58 head impacts; 74 non-head impacts). Based on the test dataset results, the mouthguard sensor alone detected 81.6% of video-confirmed head impacts while the ML classifier provided 98.3% precision and 100% recall, resulting in an overall head impact detection system that achieved 98.3% precision and 81.6% recall.

The Effect of Muscle Activation on Head Kinematics During Non-injurious Head Impacts in Human Subjects

In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact.

Institutionally Based ImPACT Test® Normative Values May Differ from Manufacturer-Provided Normative Values

OBJECTIVE

The necessity for pre-injury baseline computerized neurocognitive assessments versus comparing post-concussion outcomes to manufacturer-provided normative data is unclear. Manufacturer-provided norms may not be equivalent to institution-specific norms, which poses risks for misclassifying the presence of impairment when comparing individual post-concussion performance to manufacturer-provided norms. The objective of this cohort study was to compare institutionally derived normative data to manufacturer-provided normative values provided by ImPACT® Applications, Incorporated.

METHOD

National Collegiate Athletic Association Division 1 university student athletes (n = 952; aged 19.2 ± 1.4 years, 42.5% female) from one university participated in this study by completing pre-injury baseline Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) assessments. Participants were separated into 4 groups based on ImPACT's age and gender norms: males <18 years old (n = 186), females <18 years old (n = 165), males >19 years old (n = 361) or females >19 years old (n = 240). Comparisons were made between manufacturer-provided norms and institutionally derived normative data for each of ImPACT's clinical composite scores: Verbal (VEM) and Visual (VIM) Memory, Visual Motor Speed (VMS), and Reaction Time (RT). Outcome scores were compared for all groups using a Chi-squared goodness of fit analysis.

RESULTS

Institutionally derived normative data indicated above average performance for VEM, VIM, and VMS, and slightly below average performance for RT compared to the manufacturer-provided data (χ2 ≥ 20.867; p < 0.001).

CONCLUSIONS

Differences between manufacturer- and institution-based normative value distributions were observed. This has implications for an increased risk of misclassifying impairment following a concussion in lieu of comparison to baseline assessment and therefore supports the need to utilize baseline testing when feasible, or otherwise compare to institutionally derived norms rather than manufacturer-provided norms.

A-16 The Clinical Utility of a Novel Dual-Task Assessment for Sport-Related Concussion in Collegiate Athletes

Objective

To compare the clinical utility of a novel dual-task assessment for sport-related concussion (SRC) to other commonly-used clinical measures in collegiate athletes.

Method

Participants consisted of 38 collegiate athletes (19 concussed and 19 matched comparisons, 53% male, age = 20.0 ± 1.34 years, height = 178.2 ± 12.12 cm, mass = 83.4 ± 21.89 kg). Participants were administered the dual-task assessment, Balance Error Scoring System (BESS), Standardized Assessment of Concussion (SAC), and tandem gait (TG) test within 48 hours (T1), at 5 days (T2), and when symptom-free (T3) following a diagnosed SRC. The novel dual-task assessment consisted of concurrent administration of the SAC and TG. The ImPACT and Sensory Organization Test (SOT) were administered at T3 in alignment with the university’s concussion management policy. Sensitivity, specificity, and diagnostic accuracy using receiver operator curve analyses were calculated for each measure for T1-T3 using previously established interpretation guidelines.

Results

For sensitivity, a range of values were observed from T1-T3 for the dual-task (88%–37%), BESS (47%–47%), SAC (53%–26%), TG test (53%–11%). Similarly, a range of specificity values were observed for the dual-task (58%–84%), BESS (84%–63%), SAC (79%–84%), and TG test (95%–100%) from T1-T3. At T3, the ImPACT and SOT were observed to have a sensitivity of 32% and 100% and specificity of 16% and 100%, respectively. A range of diagnostic accuracy values were observed from T1-T3 for the dual-task (84%–62%), BESS (59%–50%), SAC (64%–56%), TG test (82%–71%), ImPACT (T3 = 66%), and SOT (T3 = 50%).

Conclusions

The dual-task assessment had comparable or higher diagnostic accuracy as other commonly-used clinical measures of SRC throughout clinical recovery in collegiate athletes.

Whole-Body Metabolism, Carbohydrate Utilization, and Caloric Energy Balance After Sport Concussion: A Pilot Study

BACKGROUND

Sport concussion (SC) causes an energy crisis in the brain by increasing energy demand, decreasing energy supply, and altering metabolic resources. Whole-body resting metabolic rate (RMR) is elevated after more severe brain injuries, but RMR changes are unknown after SC. The purpose of this study was to longitudinally examine energy-related changes in collegiate athletes after SC.

HYPOTHESIS

RMR and energy consumption will increase acutely after SC and will return to control levels with recovery.

STUDY DESIGN

Case-control study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 20 collegiate athletes with SC (mean age, 19.3 ± 1.08 years; mean height, 1.77 ± 0.11 m; mean weight, 79.6 ± 23.37 kg; 55% female) were compared with 20 matched controls (mean age, 20.8 ± 2.17 years; mean height, 1.77 ± 0.10 m; mean weight, 81.9 ± 23.45 kg; 55% female). RMR, percentage carbohydrate use (%CHO), and energy balance (EBal; ratio between caloric consumption and expenditure) were assessed 3 times: T₁, ≤72 hours after SC; T₂, 7 days after T₁; and T_F, after symptom resolution. A 2 × 2 × 3 (group × sex × time) multivariate analysis of variance assessed RMR, %CHO, and EBal. Changes in RMR, %CHO, and EBal (T₁ to T_F) were correlated with days to symptom-free and days to return to play in the concussed group.

RESULTS

Women reported being symptom-free (median, 6 days; range, 3-10 days) sooner than men (median, 11 days; range, 7-16 days). RMR and %CHO did not differ across time between groups or for group × sex interaction. SC participants had higher EBal than controls at T₁ (P = 0.016) and T₂ (P = 0.010). In men with SC, increasing %CHO over time correlated with days to symptom-free (r = 0.735 and P = 0.038, respectively) and days to return to play (r = 0.829 and P = 0.021, respectively).

CONCLUSION

Participants with SC were in energy surplus acutely after injury. Although women recovered more quickly than men, men had carbohydrate metabolism changes that correlated with recovery time.

CLINICAL RELEVANCE

This pilot study shows that male and female student-athletes may have differing physiologic responses to SC and that there may be a role for dietary intervention to improve clinical outcomes after SC.

If Not Now, When? An Absence of Neurocognitive and Postural Stability Deficits in Collegiate Athletes with One or More Concussions

A history of concussion has been associated with decreased neurocognitive function and postural control. The purpose of our study was to compare neurocognitive function and postural control in collegiate athletes with and without varying histories of concussion. Collegiate athletes were divided into groups based on 0 (n = 129), 1 (n = 91), 2 (n = 52), and 3+ (n = 34) prior concussions. Participants in each group were carefully matched by sport, sex, height, weight, and age. Athletes were administered the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT™) and the Sensory Organization Test (SOT) as part of a standard of care pre-season assessment. Group ImPACT (Verbal and Visual Memory, Visual Motor Speed, and Reaction Time) and SOT (Equilibrium Score and Somatosensory, Visual, and Vestibular sensory ratios) outcome scores were compared using one-way analyses of variance (ANOVAs). Coefficients of variation (CVs) were also calculated for each outcome score and were compared using two-sample tests with 95% confidence intervals (CIs). Participants with and without a history of concussion were not significantly different for any ImPACT or SOT outcome score (p's > 0.10). Groups (0, 1, 2, and 3+ previous concussions) were not different from each other for any ImPACT or SOT outcome score (p's ≥ 0.11). Likewise, the CVs associated with each ImPACT and SOT outcome score did not vary significantly between outcome scores for any group comparison (p ≥ 0.09). Our findings suggest that a history of one or more concussions does not influence neurocognitive performance or postural stability in collegiate athletes at their pre-season baseline assessment.

The Influence of Hormonal Contraceptives on Baseline ImPACT Performance

Purpose

Our study examined the influence of hormonal contraceptives (HC) on pre-injury (baseline) ImPACT performance in female collegiate athletes.

Methods

Participants in our cross-sectional study consisted of 304 NCAA Division I female athletes who self-reported taking (HC+ [n=154]) or not taking (HC- [n=154]) HC. HC+ participants were matched to HC- participants for height, weight, sport, and position. HC+ participants had an average age of 19.0±1.33 years, height of 170.5–8.70 cm, and mass of 64.2–10.58 kg. HC- participants had an average age of 19.0±1.24 years, height of 170.3–9.19 cm, and mass of 64.2–9.75 kg. Participants completed ImPACT as part of their preseason baseline assessment. Only participants with valid ImPACT assessments were included in our analyses. Chi-squared (χ2) tests were performed to compare groups in terms of medical history variables. Independent t-tests were used to compare groups in terms of demographic variables, self-reported hours of sleep, and ImPACT (Verbal and Visual Memory, Visual Motor Speed [VMS], Reaction Time [RT], and Total Symptom Severity [TSS]) outcome scores. Analyses were performed with α=0.05.

Results

No differences were observed between groups for demographic variables, hours of sleep, or medical history variables (p<0.05). For VMS, the HC- group (42.9+5.63) scored significantly worse (t[304]=2.17, p=0.03; d=0.25; 95% CI [0.1, 2.7]) than the HC+ group (44.3+5.67). For RT, the HC- group (0.55+0.06) performed significantly slower (t[304]=-2.02, p=0.05; d=0.23; 95% CI [-0.03, -0.0003]) than the HC+ group (0.54+0.05).

Conclusion

Our results suggest HCs may influence ImPACT performance in female collegiate athletes. Clinicians must consider the role of HCs when interpreting ImPACT outcome scores.

The Test-Retest Reliability of a Clinically-Relevant Dual-Task Assessment in Healthy College Students

Purpose

The dual-task (DT) paradigm consists of concurrent administration of motor and cognitive tasks which may demonstrate improved measurement properties of the included tasks as compared to independent administration. Our study examined the test-retest reliability of a clinically-relevant DT assessment.

Methods

Our prospective cohort study included 60 (53.3% female) healthy, recreationally active college students (Age=20.5–1.34 years; Height=171.7–9.33 cm). Participants completed the Standardized Assessment of Concussion (SAC) and timed tandem gait (TTG) test concurrently for the DT assessment at two time points separated by a two-week test-retest interval. The SAC composite score (45 points) was calculated by summing the domain scores of immediate memory (30 points) which consisted of a 10-word list, concentration (5 points), and delayed recall (10 points). The TTG composite score was calculated by summing the mean time to complete the TTG during each SAC task (3 trials for immediate memory, up to 5 trials for the digits-backwards task, and one trial for the months in reverse order and delayed recall tasks). Mixed-model intraclass correlation coefficients (ICC[3,1]) with 95% confidence intervals were calculated to evaluate test-retest reliability between time points for the SAC and TTG composite scores.

Results

Mean SAC (39.4–3.80 vs. 39.6–3.49 points) and TTG (52.1–9.44 vs. 48.2–8.33 sec) composite scores were observed at time points 1 and 2, respectively. Moderate (ICC[3,1]=0.56 [0.26, 0.74]) and good (ICC[3,1]=0.88 [0.80, 0.93]) test-retest reliability were observed for the SAC and TTG composite scores, respectively.

Conclusion

Test-retest reliability for our DT assessment aligns with previously established values for independent administration of the SAC and TTG.

Running biomechanics as measured by wearable sensors: effects of speed and surface

Running biomechanics research has traditionally occurred in the laboratory, but with the advent of wearable sensors measurement of running biomechanics may shift outside the laboratory. The purpose was to determine if RunScribe™ wearable sensors could detect differences in kinematic, kinetic and spatiotemporal measures during runs at two speeds and on two different surfaces. Fifteen recreational runners (7 males, 8 females; age = 20.0 ± 3.1 years) participated. While wearing sensors on the heels of their shoes, participants completed four 1600 m runs on both track and grass surfaces. On each surface, the first 1600 m was at a self-selected slow speed followed by the second 1600 m at a self-selected fast pace. The sensors quantified several kinetic, kinematic and spatiotemporal measures. Repeated measures ANOVAs compared the effects of surface and speed. The spatiotemporal measures of stride length, cycle time and contact time were predictably affected by increased running speed and increased surface stiffness, as were the kinematic and kinetic measurements of maximum pronation velocity, maximum pronation excursion, impact g, and braking g (p < 0.050). The RunScribe™ sensors identified expected changes in running biomechanics measures at different speeds and on varying surfaces.

Return to Learn After Sport-Related Concussion: A Survey of Secondary School and Collegiate Athletic Trainers

CONTEXT

Recent recommendations have emphasized return-to-learn (RTL) protocols to aid athletes in recovery from sport-related concussion (SRC) but have been based primarily on anecdotal evidence.

OBJECTIVE

To investigate the RTL practices of certified athletic trainers (ATs) after an SRC.

DESIGN

Cross-sectional study.

SETTING

Online survey.

PATIENTS OR OTHER PARTICIPANTS

A total of 1083 individuals (27%) from a random sample of 4000 ATs in the National Athletic Trainers' Association membership database completed an electronic survey. Participants consisted of 729 self-identified secondary school ATs (SSATs; 67.3%; experience = 14.0 ± 9.7 years) and 354 self-identified collegiate ATs (CATs; 32.7%; experience = 13.4 ± 9.7 years).

MAIN OUTCOME MEASURE(S)

We used χ² analyses to assess respondent differences related to current knowledge, current practices, and available resources. Independent t tests were used to compare SSATs and CATs on years of certification and annual number of SRCs evaluated.

RESULTS

Of our total respondents, 41.2% (n = 446) correctly indicated the absence of evidence-based RTL guidelines. Whereas most (73.9%, n = 800) respondents had an established RTL policy, only 38.1% (n = 413) used such guidelines in their clinical practice. Most (97.1%, n = 708) SSATs and 82.2% (n = 291) of CATs had access to (a) mental health professional(s); however, minorities of SSATs (21.4%, n = 156) and CATs (37.0%, n = 131) never accessed these resources to care for concussed student-athletes.

CONCLUSIONS

Our results suggested that, despite the absence of empirical evidence, most surveyed ATs incorporated some form of RTL protocol in their SRC management policy. The varying AT knowledge, clinical practices, and resources highlighted by our results should be considered when creating or refining an RTL protocol.

Sport Concussion and the Female Athlete

Sport concussion (SC) has emerged as a major health concern in the medical community and general public owing to increased research and media attention, which has primarily focused on male athletes. Female athletes have an equal, if not increased, susceptibility to SC. An ever-growing body of research continues to compare male and female athletes in terms of SC before and after an injury. Clinicians must be cognizant of this literature to make evidence-based clinical decision when providing care to female athletes and discern between dated and/or unsupported claims in terms of SC.

The test-retest reliability of three computerized neurocognitive tests used in the assessment of sport concussion

Computerized neurocognitive tests (CNTs) are widely used at all competitive levels of sport to assess sport concussion (SC). Whereas there are multiple CNTs available, little is known about how some of the most popular platforms compare. The purpose of this study was to investigate the test-retest reliability of the Automated Neuropsychological Assessment Metrics (ANAM), Concussion Vital Signs (CVS) and the Immediate Postconcussion and Cognitive Testing battery (ImPACT) using clinically relevant time points in healthy college-age participants. Participants were healthy college-age students (N=128) randomly assigned into one of three groups which were administered ANAM, CVS, or ImPACT at Days 1, 45 and 50. Intraclass correlation coefficients (ICCs) and Pearson correlations were used to assess reliability of the various CNT scores and subtest scores between time points. Participants were tested approximately 47.1±2.75days after time point 1 and approximately 7.0±2.45days after time point 2. ICC values ranged from 0.18 (Procedural Reaction Time) to 0.53 (Mathematical Processing and Simple Reaction Time 1) for ANAM, 0.14 (Continuous Performance Test) to 0.85 (Reaction Time) for CVS, and 0.19 (Verbal Memory) to 0.89 (Visual Motor Speed) for ImPACT. Significant improvements (p<0.05) across time were observed for (7/10) CNS Vital Signs composite scores, but no additional significant changes in performance were observed for the remaining CNTs. Overall, weak to strong reliability coefficients for ANAM, CVS, and ImPACT were observed when using clinically relevant time points of repeated administration.

TWO-DIMENSIONAL VIDEO ANALYSIS IS COMPARABLE TO 3D MOTION CAPTURE IN LOWER EXTREMITY MOVEMENT ASSESSMENT

BACKGROUND

Although 3D motion capture is considered the "gold standard" for recording and analyzing kinematics, 2D video analysis may be a more reasonable, inexpensive, and portable option for kinematic assessment during pre-participation screenings. Few studies have compared quantitative measurements of lower extremity functional tasks between 2D and 3D.

PURPOSE

To compare kinematic measurements of the trunk and lower extremity in the frontal and sagittal planes between 2D video camera and 3D motion capture analyses obtained concurrently during a SLS.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twenty-six healthy, recreationally active adults volunteered to participate. Participants performed three trials of the single leg squat on each limb, which were recorded simultaneously by three 2D video cameras and a 3D motion capture system. Dependent variables analyzed were joint displacement at the trunk, hip, knee, and ankle in the frontal and sagittal planes during the task compared to single leg quiet standing.

RESULTS

Dependent variables exhibited moderate to strong correlations between the two measures in the sagittal plane (r = 0.51-.093), and a poor correlation at the knee in the frontal plane (r = 0.308) at (p ≤ 0.05) All other dependent variables revealed non-significant results between the two measures. Bland-Altman plots revealed strong agreement in the average mean difference in the amount of joint displacement between 2D and 3D in the sagittal plane (trunk = 1.68 º, hip = 2.60 º, knee = 0.74 º, and ankle = 3.12 º). Agreement in the frontal plane was good (trunk = 7.92 °, hip = -8.72 º, knee = -6.62 º, and ankle = 3.03 °).

CONCLUSION

Moderate to strong relationships were observed between 2D video camera and 3D motion capture analyses at all joints in the sagittal plane, and the average mean difference was comparable to the standard error of measure with goniometry. The results suggest that despite the lack of precision and ability to capture rotations, 2D measurements may provide a pragmatic method of evaluating sagittal plane joint displacement for assessing gross movement displacement and therein risk of lower extremity injury.

LEVEL OF EVIDENCE

3.

Exertional Heat Illness in American Football Players: When Is the Risk Greatest?

CONTEXT

Knowledge about the specific environmental and practice risks to participants in American intercollegiate football during preseason practices is limited. Identifying risks may mitigate occurrences of exertional heat illness (EHI).

OBJECTIVE

To evaluate the associations among preseason practice day, session number, and wet bulb globe temperature (WBGT) and the incidence of EHI.

DESIGN

Descriptive epidemiology study.

SETTING

Sixty colleges and universities representing 5 geographic regions of the United States.

PATIENTS OR OTHER PARTICIPANTS

National Collegiate Athletic Association football players.

MAIN OUTCOME MEASURE(S)

Data related to preseason practice day, session number, and WBGT. We measured WBGT every 15 minutes during the practice sessions and used the mean WBGT from each session in the analysis. We recorded the incidence of EHIs and calculated the athlete-exposures (AEs).

RESULTS

A total of 553 EHI cases and 365 810 AEs were reported for an overall EHI rate of 1.52/1000 AEs (95% confidence interval [CI] = 1.42, 1.68). Approximately 74% (n = 407) of the reported EHI cases were exertional heat cramps (incidence rate = 1.14/1000 AEs; 95% CI = 1.03, 1.25), and about 26% (n = 146) were a combination of exertional heat syncope and heat exhaustion (incidence rate = 0.40/1000 AEs; 95% CI = 0.35, 0.48). The highest rate of EHI occurred during the first 14 days of the preseason period, and the greatest risk was during the first 7 days. The risk of EHI increased substantially when the WBGT was 82.0°F (27.8°C) or greater.

CONCLUSIONS

We found an increased rate of EHI during the first 14 days of practice, especially during the first 7 days. When the WBGT was greater than 82.0°F (27.8°C), the rate of EHI increased. Sports medicine personnel should take all necessary preventive measures to reduce the EHI risk during the first 14 days of practice and when the environmental conditions are greater than 82.0°F (27.8°C) WBGT.

Treatment of Head and Neck Injuries in the Helmeted Athlete

Sport-related concussion treatment includes three major phases: initial evaluation at the time of the injury, treatment while the patient is symptomatic, and evaluation of the readiness for a gradual return to participation. Each concussion evaluation should include similar elements: assessment of symptoms, assessment of cognitive ability, assessment of coordination (of the eyes, upper extremities, and lower extremities), and assessment for additional injuries. The spine-boarding recommendations from the American College of Emergency Physicians, National Association of EMS Physicians, and National Athletic Trainers' Association have changed. These recommendations include both decreased use of spinal immobilization and removal of the helmet and shoulder pads prior to securing the athlete to the board when sufficient numbers of trained providers are present. Preseason training and pregame meetings or "medical time outs" should become standard practice for the sidelines medical team (including the athletic trainer, team physician, emergency response personnel, and possibly others).

The sensitivity and specificity of clinical measures of sport concussion: three tests are better than one

CONTEXT

A battery of clinical measures of neurocognition, balance and symptoms has been recommended for the management of sport concussion (SC) but is based on variable evidence.

OBJECTIVE

To examine the sensitivity and specificity of a battery of tests to assess SC in college athletes.

DESIGN

Cross-sectional.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Division 1 athletes diagnosed with a SC (n=40) who were 20.2±1.60 years of age and 180.5±11.12 cm tall and healthy athletes (n=40) who were 19.0±0.93 years of age and 179.1±11.39 cm tall were enrolled.

INTERVENTIONS

Participants were administered Immediate Postconcussion Assessment and Cognitive Test (ImPACT), the Sensory Organization Test (SOT) and the Revised Head Injury Scale (HIS-r) prior to and up to 24 h following injury between the 2004 and 2014 sport seasons. Sensitivity and specificity were calculated using predictive discriminant analyses (PDA) and clinical interpretation guidelines.

MAIN OUTCOME MEASURES

Outcome measures included baseline and postinjury ImPACT, SOT and HIS-r composite scores.

RESULTS

Using PDA, each clinical measure's sensitivity ranged from 55.0% to 77.5% and specificity ranged from 52.5% to 100%. The test battery possessed a sensitivity and specificity of 80.0% and 100%, respectively. Using clinical interpretation guidelines, sensitivity ranged from 55% to 97.5% individually, and 100% when combined.

CONCLUSIONS

Our results support a multidimensional approach to assess SC in college athletes which correctly identified 80-100% of concussed participants as injured. When each test was evaluated separately, up to 47.5% of our sample was misclassified. Caution is warranted when using singular measures to manage SC.

A Preliminary Formula to Predict Timing of Symptom Resolution for Collegiate Athletes Diagnosed With Sport Concussion

CONTEXT

Symptom presentation and recovery after sport concussion (SC) are variable. Empirically based models documenting typical symptom duration would assist health care providers in managing return to play after SC.

OBJECTIVE

To develop a prediction model for SC symptom duration.

DESIGN

Cross-sectional study.

SETTING

Two National Collegiate Athletic Association Division I university laboratories.

PATIENTS OR OTHER PARTICIPANTS

Seventy-six (51 male and 25 female) concussed athletes with an average age of 19.5 ± 1.65 years who were evaluated within 24 hours of diagnosis.

INTERVENTION(S)

Participants completed the Revised Head Injury Scale (HIS-r), Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and Sensory Organization Test within 24 hours of SC diagnosis.

MAIN OUTCOME MEASURE(S)

A stepwise multivariate regression incorporating ImPACT and Sensory Organization Test composites and HIS-r symptom severity-duration was used to predict the number of days athletes reported symptoms after SC. The resulting regression formula was cross-validated using the Stine cross-validation coefficient.

RESULTS

The final formula consisted of the HIS-r's self-reported neck pain, drowsiness, tingling, and nervousness duration and ImPACT total symptom severity (R = 0.62, R(2) = 39%, R(2)(adj) = 34.2%, P < .001). Approximately 29% (R(2)(cv) = 29%) of the variance associated with total days symptomatic after SC was explained by our preliminary formula when cross-validated. The current formula correctly identified 76% of participants who recovered within 10 days of injury.

CONCLUSIONS

Our results suggest that self-reported duration of 4 symptoms during the initial 24 hours after injury along with total symptom severity as measured by ImPACT accounted for a considerable amount of variance associated with days symptomatic after SC in collegiate athletes. Until the formula is cross-validated in a college-aged sample, caution is warranted in using it clinically.

The Acute Management of Sport Concussion in Pediatric Athletes

During the past two decades the focus on sport concussion has increased significantly. Young athletes represent the most vulnerable population to sustain a sport concussion yet receive the least amount of attention. Specifically, young athletes who sustain a sport concussion can go unrecognized and continue to participate in sport putting them at an increased risk for a more significant injury. The purpose of this review is to provide a clinical framework for the evaluation and management of sport concussion. In addition, this review provides considerations for health care professionals in regard to clinical measures and follow-up strategies during the acute phase following concussion in young concussed athletes following injury.

Balance performance with a cognitive task: a continuation of the dual-task testing paradigm

CONTEXT

To ensure that concussed athletes return to play safely, we need better methods of measuring concussion severity and monitoring concussion resolution.

OBJECTIVE

To develop a dual-task model that assesses postural stability and cognitive processing in concussed athletes.

DESIGN

Repeated measures study.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty healthy, college-aged students (10 men, 10 women; age  =  20 ± 1.86 years, height  =  173 ± 4.10 cm, mass  =  71.83 + 35.77 kg).

INTERVENTION(S)

Participants were tested individually in 2 sessions separated by 2 days. In one session, a balance task and a cognitive task were performed separately. In the other session, the balance and cognitive tasks were performed concurrently. The balance task consisted of 6 conditions of the Sensory Organization Test performed on the NeuroCom Smart Balance Master. The cognitive task consisted of an auditory switch task (3 trials per condition, 60 seconds per trial).

MAIN OUTCOME MEASURE(S)

For the balance test, scores for each Sensory Organization Test condition; the visual, vestibular, somatosensory, and visual-conflict subscores; and the composite balance score were calculated. For the cognitive task, response time and accuracy were measured.

RESULTS

Balance improved during 2 dual-task conditions: fixed support and fixed visual reference (t18  =  -2.34, P < .05) and fixed support and sway visual reference (t18  =  -2.72, P  =  .014). Participants' response times were longer (F1,18  =  67.77, P < .001, η2  =  0.79) and choice errors were more numerous under dual-task conditions than under single-task conditions (F1,18  =  5.58, P  =  .03, η2  =  0.24). However, differences were observed only during category-switch trials.

CONCLUSIONS

Balance was either maintained or improved under dual-task conditions. Thus, postural control took priority over cognitive processing when the tasks were performed concurrently. Furthermore, dual-task conditions can isolate specific mental processes that may be useful for evaluating concussed individuals.