bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of a rule change on concussions and other injuries in professional baseball
Authors: Gary Green , D’Angelo John , Coyles Jon , Valadka Alex
Published: November 2017

Objective

To evaluate the hypothesis that a rule change can lower the incidence of concussions and other injuries in professional baseball.

Design

Retrospective review of professional baseball’s electronic medical record system. All Minor (MiLB) and Major League Baseball (MLB) teams are required to use this system.

Setting

Five full MiLB and MLB seasons in the United States and Canada.

Participants

All players in MiLB and MLB were included. The 30 MLB clubs have 750 active players and play 162 games per season. MiLB has approximately 7500 active players on 200 teams that play 56-144 games annually.

Intervention

Before the 2014 season, MLB instituted a rule limiting home plate collisions between base runners and catchers.

Outcome measures

All concussions and other injuries at home plate from 2011 to 2015 were analysed by mechanism and player position.

Main results

From 2011-2013, an annual average of 117 injuries occurred at home plate in both MiLB and MLB, with an average of 4823 days lost annually. An average of 13 concussions occurred annually in both MiLB and MLB. Following the rule change, in 2014-2015 there was an annual average of 60 home plate injuries with 1592 days lost. There were 6 MiLB home plate concussions in 2014 and none in 2015. There were no home plate concussions in MLB in 2014-2015 (p=0.07). MiLB and MLB combined for approximately 660,000 athlete exposures per season.

Conclusions

This rule change was associated with a strong trend toward reduced concussions and other injuries at home plate.

Competing interests

Mr. D’Angelo and Mr. Coyles are employed by Major League Baseball. Dr. Green receives payment from Major League Baseball for his role as Medical Director. Dr. Valadka is a paid consultant to Major League Baseball. The authors have no other disclosures to report.
Head and neck size and neck strength minimise the head acceleration during repeated head impacts
Authors: Caccese Jaclyn B , Buckley Thomas A , Tierney Ryan T , Rose William C , Arbogast Kristy B , Glutting Joseph J , Kaminski Thomas W
Published: November 2017

Objective

To identify factors that contribute to head acceleration during purposeful soccer heading.

Design

Prospective.

Setting

Biomechanics laboratory.

Participants

One-hundred soccer players (42 male, 58 female, 17.1±3.5 years (range: 12-24years), 168.5±20.3 cm, 61.5±13.7 kg). Exclusionary criteria: history of neurologic disorder, cervical spine injury, or head injury in the past 6 months.

Interventions

We implemented a soccer heading paradigm that consists of controlled soccer heading (12 headers at 11.2m/s from a JUGS machine) while measuring 3D motion capture kinematics (torso and head-to-torso range-of-motion), sternocleidomastoid and upper trapezius EMG activity (peak and area), and linear and rotational accelerations using a triaxial accelerometer and gyroscope. Head mass, neck girth, and sternocleidomastoid and upper trapezius strength were also evaluated.

Outcome measures

Linear and rotational accelerations at the head center-of-gravity.

Main results

Multiple regression analyses suggest that the ten variables predicted linear (R2=0.272, p=0.002) and rotational (R2=0.259, p=0.004) acceleration; however none of the predictors individually made a significant contribution to the model. Linear and rotational accelerations were correlated with head mass (r=-?0.447, p<0.001; r=-0.467,p<0.001), neck girth (r=-0.465, p<0.001; r=-0.438, p<0.001), sternocleidomastoid strength (r=-0.386, p<0.001; r=-0.410, p<0.001), and upper trapezius strength (r=-0.311, p=0.001; r=-0.351, p<0.001).

Conclusions

Our findings suggest that head mass, neck girth, and neck strength are important in minimising head acceleration, whereby greater size and strength are associated with lower head accelerations. Soccer players with smaller head-neck segment masses and lower neck strength, may be at risk for greater head acceleration. These athletes may experience a theoretical bobble-head effect, when the neck strength is not great enough to control the mass of the head.

Competing interests

None.
Improved prediction of subconcussive neurophysiological changes by kinematic impulse
Authors: Talavage Thomas M , Breedlove Katherine M , Breedlove Evan L , Abbas Kausar , Shenk Trey , Bowman Thomas G , Nauman Eric A , Leverenz Larry J
Published: November 2017

Objective

For both subconcussive impacts and traditionally-defined concussion, neither the number of head impacts nor the magnitude has had a strong correlation to the incidence or severity of injury. Recent modelling work has suggested that impulse may be an important biomechanical factor, and therefore it is hypothesised that it may be a good predictor of subconcussive neurophysiological changes.

Design

Observational study.

Setting

American high school football team.

Participants

Nine male high school football athletes (mean age=16.4, range=15–17) volunteered. All participants were enrolled with parental consent.

Assessment of risk factors

Head impacts were monitored at all practices and games with the Head Impact Telemetry System. Baseline neurophysiology was measured prior to contact activity using a functional magnetic resonance imaging (fMRI) visual n-back task protocol. Subjects returned throughout the season and were re-evaluated according to the same protocol.

Outcome measures

Kinematic impulse was computed from head impact telemetry. Changes in neurophysiology were determined as the difference in the 2 vs. 1-back contrast. This contrast was determined for 116 anatomically defined regions of interest (ROI).

Main results

Stepwise regressions (P=0.05) relating kinematic impulse to ROI-specific changes in neurophysiology yielded significant correlations for 57/116 ROIs. 22/116 ROIs had an R2 value greater than 0.70. Correlations were found bilaterally for 16 anatomical ROIs, including the executive pre-frontal regions, basal ganglia, and thalamus.

Conclusions

The relationship between kinematic impulse and fMRI changes reported here are the strongest correlations to subconcussive changes reported to date. Correlations were observed bilaterally in regions associated with concussion symptoms.

Competing interests

None.
Previous concussion history influences neurological assessments following an acute bout of purposeful heading in women’s collegiate soccer
Authors: Kaminski Thomas W , Kimmelmann Briana , Caccese Jaclyn B , Glutting Joseph J
Published: November 2017

Objective

Do differences in neurological assessments exists in a cohort of intercollegiate soccer players with varied concussion histories after an acute bout of soccer heading?

Design

Pre-posttest.

Setting

Soccer turf field and clinic.

Participants

67 female collegiate soccer athletes (age=19.1 ± 0.9 yr.; mass=60.5 ± 5.0 kg; height=165.3 ± 5.9 cm). Based on their concussion history subjects were assigned to either the control/simulated heading [G1-17], control/heading [G2-22] 1–2 previous concussion/heading [G3-19], and 3 or more concussion/heading [G4-9] groups.

Interventions

Concussion symptoms (SX), BESS errors, ImPACT NP test scores were derived prior to and immediately after a bout of heading (15 total headers/15 minutes @ 12 m/s). Subjects returned to the clinic for post-testing immediately after heading.

Outcome measures

SX, BESS and NP scores pre and post ROT and LIN heading.

Main results

G3 (3.9±4.4) and G4 (5.1±6.0) demonstrated higher SX pre-heading compared to G1 (1.9±2.4) and G2 (3.2±3.7). Excluding G1, all groups showed elevated SX post-heading. There was a significant (p=.05) time by group interaction for SX whereby SX in G4 (7.8±7.1; 95% CI=4.9 – 10.7) were significantly (p=0.03) higher post-heading than G1 (2.0±2.5; 95% CI=−0.02 – 4.2).

Conclusions

Subjects in G4 had elevated SX at baseline, and those SX appear to be greatly exaggerated immediately following an acute bout of heading. Clinicians should carefully monitor soccer players who have experienced multiple concussions and be cognizant that they may develop concussion-like symptoms, especially after acute bouts of heading. Limitations in soccer heading should also be considered for this group of soccer athletes.

Competing interests

None.
Post-concussion abnormalities in the m60 somatosensory evoked field recorded by magnetoencephalography
Authors: Wennberg Richard , El-Rahimy Youssef , Shampur Nat , Dominguez Luis Garcia
Published: November 2017

Objective

We sought to determine whether magnetoencephalography (MEG) might reliably document the presence of neurophysiologic dysfunction after acute concussion. Based on a previous evoked potential study,1we analysed somatosensory evoked fields (SEFs) elicited by stimulation of the median nerve at the wrist.

Design

Case-control study.

Setting

Academic tertiary care centre.

Participants

Five patients with acute concussion (<10 days post-injury); mean age 32±18 yrs, 3 women. 23 age/sex matched controls with no history of concussion.

Assessment of risk factor

Independent variable, concussion.

Outcome measures

Dependent variables, bilateral peak latencies of M20, M30, and M60 SEFs.

Main results

No differences were found between patients (24 recorded values) and controls (46 recorded values) in M20 (21.7±1.6 ms vs. 22.3±1.5 ms) or M30 (35.4±3.8 ms vs. 33.5±3.3 ms) latencies. M60 latencies were significantly delayed in patients compared to controls (90.4±21.5 ms vs. 64.0±8.6 ms; Mann Whitney U-test, U=186.5, p=0.0001). All symptomatic patients had an abnormally delayed M60 value>2 SDs from the control mean on at least one side. Follow-up patient recordings showed gradual decreases in abnormal M60 latencies over months; weekly MEG and ImPACT testing in one patient showed normalisation of verbal memory at week 2, visual memory and symptom scores at week 5 and M60 latencies at week 10.

Conclusions

The M60 SEF represents the first intracortical stage of neuronal processing of external somatosensory input to the brain. In this preliminary study we found significant differences in M60 latencies between subjects with acute concussion and controls, as well as within subject changes during recovery in the weeks after concussion.

Competing interests

None.
Regulator-watching: a typology of regulatory methods adopted by sports governing bodies in concussion management
Authors: Greenhow Annette
Published: November 2017

Objective

Responses to the harm caused by sports-related concussion constitute a new interdisciplinary field of research (Doherty, 2012). Regulatory theory and principles of what constitutes ‘good’ regulation can contribute to the discussion. The aim of this research is to present a typology of regulatory responses adopted by sports governing bodies in those sports with published injury surveillance data, and to classify the responses according to the regulatory methods used by the organisations.Sports governing bodies are voluntary self-regulated associations and custodians of their sport. As the dominant regulator responsible for the development of rules and standards, the organisation carries the responsibility to provide a safe system for participants within its regulatory field, focussing on precautionary-based approaches and risk reduction strategies to preserve the health, safety and welfare of participants. The expectation is that these interventions are based on well-defined objectives and an understanding of the variety of regulatory methods available to achieve the objectives.

Design

This presentation provides the results of a review of the regulatory activities of the sports governing bodies across contact and collision sport. By adopting a qualitative research method, the regulatory actions of the organisations are classified according to the four response areas of concussion management, concussion prevention, concussion research and concussion education.

Main results

A variety of regulatory methods were employed by the organisations across each of the four categories. Early interventions focus on concussion management and concussion prevention with more recent interventions focussed on concussion education and concussion research strategies.

Conclusions

Those organisations with clearly defined objectives and comprehensive injury surveillance data reporting systems adopted regulatory methods across each of the four categories.

Competing interests

None
Baseline scat3 in professional football players: data from the canadian football league
Authors: Naidu Dhiren J , Hoeber Shane , Ashworth Nigel , Mrazik Martin
Published: November 2017

Objective

To establish baseline normative concussion data for Canadian Football League (CFL) players.

Design

Cross-Sectional.

Setting

Professional American football.

Participants

596 male professional football players from the 2014 CFL season. All asymptomatic players were included in the study. Players with a diagnosis of concussion were excluded.

Interventions (or Assessment of Risk Factors)

Data from the baseline SCAT3 assessments was collected and analysed to determine the prevalence and severity of symptoms on the symptom evaluation and average values for the cognitive and physical examination.

Outcome measures

Analysis of SCAT3 categories.

Main results

47.4% players had a previous concussion with symptoms lasting 6.28 (22.9)* days on average. Athletes reported 1.09 (2.13) symptoms with a total symptom score of 1.86 (4.09). The most frequently reported symptoms were nervousness/anxiety (11.9%), trouble falling asleep (11.2%), fatigue (11.2%), sensitivity to light (9.1%), and neck pain (7.7%). Scores for orientation, immediate memory, concentration, and delayed recall were 4.89 (0.35), 14.25 (1.23), 3.75 (1.16), and 3.79 (1.13) respectively. Balance testing revealed 0.02 (0.13), 1.91 (2.00), and 0.92 (1.36) errors on double leg, single leg, and tandem stance respectively. * parentheses indicate 1 standard deviation from the mean.

Conclusions

There are abnormalities on baseline SCAT3 testing of asymptomatic CFL players. This is consistent with past studies of similar athletic populations. This is expected as not all SCAT3 symptoms are specific for the diagnosis of concussion. Future research could be done to see if athletes who fall outside of the normative baseline values have different outcomes post concussion.

Competing interests

None.
Day of injury dizziness is related to prolonged recovery following concussion
Authors: Luoto Teemu M , Hänninen Timo , Parkkari Jari , Tuominen Markku , Iverson Grant L , Vartiainen Matti , Öhman Juha
Published: November 2017

Objective

To examine the relation between day of injury concussion symptomology and prolonged recovery.

Design

Prospective cohort.

Setting

Finnish professional ice hockey league.

Participants

SCAT3 baseline and post-injury testing has been mandatory in the Finnish ice hockey league since 2013. Of the reported injuries, between seasons 2013-2016, all cases with a day of injury SCAT3 symptom scale completed were selected. The teams’ medical staff confirmed 28 concussions, which were assessed on the day of injury.

Outcome measures

The SCAT3 symptom scale was completed on the day of injury. All 22 symptoms were analysed separately. Team medical staff followed up all concussed players and the day of return to play (RTP) was recorder for each athlete. Concussion recovery was considered prolonged if the time of RTP was over 10 days. RTP was analysed as a continuous and a dichotomized variable.

Main results

All concussed players (n=28) were Caucasian. The average age was 26.4 years (SD=4.3). The mean Symptom Score was 12.1 (SD=4.3) and the Symptom Severity 26.4 (SD=13.5), respectively. The median time to RTP was 9 days (M=21, SD=47, range=4–248) with 36% of the players being out of play for more than 10 days. There was a significant correlation between Symptom Severity and RTP (p=0.046). Symptom Score was not related to RTP. Dizziness was the only symptom with a consistent statistical relation to longer RTP (Spearman rho=0.4, p=0.029; Mann-Whitney U=4.9, p=0.038; Binary univariate logistic regression: OR=2.6, p=0.04).

Conclusions

Acute day of injury dizziness was related to prolonged recovery following concussion.

Competing interests

Teemu M. Luoto, Timo Hnninen, Jari Parkkari, Markku Tuominen, Matti Vartiainen, Juha hman: None.

Grant L. Iverson has been reimbursed by the government, professional scientific bodies, and commercial organisations for discussing or presenting research relating to mild TBI and sport-related concussion at meetings, scientific conferences, and symposiums. He has a clinical and consulting practice in forensic neuropsychology involving individuals who have sustained mild TBIs (including professional athletes). He has received research funding from several test publishing companies, including ImPACT Applications, Inc., CNS Vital Signs, and Psychological Assessment Resources (PAR, Inc.). He has not received research support from a test publishing company in the past 5 years.

None.
Use of the wii balance board to assess changes in postural balance across athletic season
Authors: Cullen Hilary M , Sun Yao , Christie Brian R , Paul Zehr E
Published: November 2017

Objective

The purpose of this study was to investigate potential utility of a customised Wii Balance Board (WBB) program to assess postural balance in an athletic population. Researchers hypothesised that WBB measures would be strongly correlated to the Balance Error Scoring System (BESS) used in concussion assessments.

Design

Cross-sectional time series. Static and dynamic balance was assessed using the WBB and BESS at three time points of an athletic season: 1) pre-season, 2) mid-season, and 3) post-season.

Setting

University research laboratory

Subjects

Intervention

Outcome measures

1) BESS, 2) WBB dynamic recovery time, and 3) WBB static Centre of Pressure (COP).

Results

WBB COP data were found to be strongly correlated with BESS scores across all time points [pre-season (r=0.689, p<0.05), mid-season (r=0.767, p<0.01), and post-season (r=0.780, p<0.01)]. There were significant differences in recovery time (p<0.005) and COPx variance for the single-leg BESS condition across all time points (p<0.005). No significant differences were observed in raw BESS scores across time points.

Conclusions

Study results support the use of a WBB as an objective tool in measuring variance in static and dynamic postural balance. This program has potential utility for clinicians when assessing balance deficits related to concussion. Planned work will examine the use of the WBB program in measuring variance in postural balance in individuals with sport-related concussion.

Competing interests

None.
An investigation of the role of a rapid sideline head injury assessment form (hiaf) in the clinical diagnosis of concussion in elite australian football
Authors: Clifton Patrick , Harcourt OAM Peter , Gastin Tom , Makdissi Michael
Published: November 2017

Objective

To investigate the role of a rapid sideline Head Injury Assessment Form (HIAF) in the clinical diagnosis of concussion in elite Australian football.

Design

Validation study

Setting/participants

The study was conducted in all 207 matches of the professional competition during the 2015 season.

Interventions

The HIAF comprised 12 individual tests based on previously validated clinical features1and video signs2of concussion. Experienced team physicians were required to complete the HIAF for any incident potentially resulting in a concussion. The HIAF directs team physicians to either permanently remove the player (9 of 12 tests), or conduct a more detailed assessment (e.g. SCAT3, 3 of 12 tests). Where possible, the tests were conducted by both direct assessment and video review of the incident. At the end of the season, data on all clinically confirmed concussions was collected from team physicians.

Main results

135 HIAFs were submitted throughout the 2015 season resulting in 44 players permanently removed from play for concussion. 8 confirmed concussions were not identified during the match. When compared to information on clinically confirmed concussions, the HIAF captured concussive incidents with 89% sensitivity (95% CI: 75.44% – 96.21%) and 98% specificity (95% CI: 92.03% – 99.72%).

Conclusions

The HIAF was demonstrated to have a high level of sensitivity and specificity. It is a useful precursor to the SCAT3 for the sideline diagnosis of concussion, in most cases providing a faster and more prescriptive assessment. A modified version of the HIAF may be useful in lower levels of competition.
King-devick (kd) test as a rinkside tool for concussion assessment
Authors: Rhine DJ , Lamvohee T , Rhine BD
Published: November 2017

Objective

King-Devick test as a rinkside tool for concussion diagnosis.

Design

KD was administered to hockey players immediately after removal from the game with a suspected concussion. Results were compared to baseline. Concussion was suspected with slowing by >5.2 sec.1

Setting

Hockey games.

Participants

Hockey players (male/female) – school-based hockey academy and a Canadian junior hockey team

Interventions

Athletic trainers were trained in the use of KD and obtained baseline KD times for players. AT’s administered the KD test to hockey players immediately after removal from the game with a suspected concussion.

Main outcome measures

KD time post-injury was compared to the KD time baseline.

Results

During the 2015–16 season, KD testing was collected on players with suspected concussion (42 concussions identified out of 148 players). Of the 42 concussions, 13 had KD sideline testing done immediately post-injury; 8/13 demonstrated >5.2 sec slowing in their KD baseline scores. All were further evaluated with a comprehensive concussion assessment protocol that included symptom scoring-balance assessments-cognitive testing. Concussion was confirmed with this diagnostic approach in 8/8 players with KD times slowed by more than 5.2 sec.

Abstarct 212 Table 1

King-Devick Sideline Assessment for Concussion: Diagnostic Difference >5.2 sec from Baseline

AGEGENDERSPORTBaselineSidelineΔKD14yrMaleHockey53.0861.088.0 sec14yrMaleHockey30.0942.8112.7215yrFemaleHockey42.553.511.015yrFemaleHockey37.054.023.017yrFemaleHockey46.554.057.5518yrMaleHockey36.8843.356.9719yrMaleHockey36.0161.024.9920yrMaleHockey39.0247.088.06

Conclusions

An ideal concussion sideline diagnostic tool should be inexpensive, portable, reproducible, fatigue-tolerant, resistant to test-retest learning and suitable for non-medical personnel.23The King-Devick test, that assesses saccadic eye movements, has these characteristics. It can be administered in less than 2-minutes. It has been reported that a post-injury slowing of KD times >5.2 seconds is diagnostic of concussion.4Sideline/rinkside KD testing with > 5.2 sec slowing compared to baseline results accurately identified concussion with 100% accuracy.
A workshop for educators on concussion led directly to the user-centredcentered design of a school board approved return to learn protocol
Authors: Carson James D , Garel Alisha , Rendely Alexandra , Moser Stefanie E , Rabinovitch Sarah T , Kraft Sari A , Fremont Pierre
Published: November 2017

Objective

To improve the educators’ knowledge and implementation of academic accommodations for optimal return to learn (RTL) after a sport-related concussion (SRC).

Design

Initially designed as a pre- post- intervention study, this qualitative report describes an unexpected but most relevant outcome of an educational intervention regarding SRC management in a school-based setting.

Setting

A sport-focused Ontario (Canada) secondary school.

Participants

94 educational staff, including teachers, administrators and psychologists.

Intervention

A workshop where educators learned about SRC management and reflected on their own experiences with some of the 63 cases of SRC managed at theirschool over the preceding 3.5 years. Participants were asked to develop RTLprotocols adapted for their environment.

Outcome measures

Capacity to develop RTL protocols to improve concussionmanagement in school-based settings.

main results

Working in small groups, participants were able to independently construct RTL protocols. As an unexpected outcome of this session, the educators formed a committee, which formalised a user-centred (teacher accepted and student focused) eight-stage post-SRCRTL protocol. In 2015 their school board accepted this protocol for use at over 200 schools. The index school initiated a daily accommodations update RTL passport.

Conclusions

Working in small groups, participants were able to independently construct RTL protocols. As an unexpected outcome of this session, the educators formed a committee, which formalised a user-centred (teacher accepted and student focused) eight-stage post-SRCRTL protocol. In 2015 their school board accepted this protocol for use at over 200 schools. The index school initiated a daily accommodations update RTL passport.

Competing interests

None.
Annual trends in follow-up visits for paediatricpediatric concussion in emergency departments and doctors’ offices in ontario, canada between 2003–2013
Authors: Fridman Liraz , Scolnik Michal , Macpherson Alison , Rothman Linda , Guttmann Astrid , Grool Anne , Rodriguez Duque Daniel , Zemek Roger L
Published: November 2017

Background

Over the past ten years, ED and physician office visits for paediatric concussion have more than quadrupled. Current concussion management guidelines recommend follow-upand clearance by a physician prior to resumption of contact activities. However, compliance with recommended follow-up is not well documented in the literature.

Objective

To examine trends in follow-up visits in accordance with current recommended guidelines for children with concussion.

Design

Retrospective population-based study.

Setting

Children and youth presenting to emergency departments (EDs) and doctors’ offices with concussion over a 10-year time period (2003–2013) in Ontario, Canada.

Outcome measures

We examined the percentage of children and youth who were seen for follow-up visit post-concussion. Trends in the percent of children with a follow-up visit following an index visit to either a doctor’s office or an ED were reported.

Main results

The proportion of children and youth assessed for concussion follow-up (N=45,150) has increased significantly (p<0.0001). In 2003, only 1010 of 7170 (14.2%) patients with an index visit for concussion had follow-up assessment; in 2009, 2733 of 10,134 (27.0%) had a follow-up visit, and by 2013, 11,806 of 21,681 (54.5%) received follow-up care.

Conclusions

Despite increasing trends in the proportion of children being examined for concussion follow-up over a 10-year period, nearly half of all children with an index visit for concussion still do not receive follow-up assessment. This suggests that ongoing efforts to improve compliance with recommended guidelines will be important.

Competing interests

None.
Predictors of recommended academic adjustments among concussed student-athletes presenting to the primary care setting
Authors: Wasserman Erin , Herzog Mackenzie , Register-Mihalik Johna , De Maio Valerie , Fonseca Janna , Phillips Kristen , Bloom O. Josh
Published: November 2017

Objective

The purpose was to describe academic ajdustments recommended by primary care physicians to paediatric concussion patients and to identify predictors of recommended adjustments.

Design

Prospective cohort.

Setting

Primary care sports medicine clinic.

Subjects

Participants were 8–18 years old, injured during organised or recreational sports, and presented to the clinic within 3 days of concussion.

Intervention

Symptom scores, average visual near-point convergence, and ImPACT composite scores were evaluated as predictors of accommodations using logistic regression.

Outcome measures

Academic adjustment information was obtained from a standardised, provider completed form. Patients with no recommendation form were excluded (N=31). Academic accommodations were grouped into: 1) cognitive (e.g. limited or no testing, extra time for schoolwork) and 2) visual-vestibular (e.g. auditory participation only, limited visual stimulants).

Results

163 patients met the inclusion criteria; 88 (54%) were male. The mean age was 14.3±2.2 years. Most patients received academic adjustment recommendations (N=140; 86%). 21 (13%) received cognitive recommendations, 13 (8%) visual-vestibular, and 105 (64%) both. The most common recommendations were: “Take rest breaks during the day as needed” (N=108, 66%), “Patient is to limit visual stimulants and screen time” (N=102, 63%), and “Allow extra time to complete tasks” (N=97, 60%). Patients with higher symptom scores (OR=1.03 per 1-point increase; 95% CI: 1.00–1.05; p=0.03) and lower processing speed scores (OR=1.07 per 1-point decrease; 95% CI: 1.01–1.13; p=0.02) were more likely to receive visual-vestibular accommodations. There were no significant predictors of cognitive adjustments.

Conclusions

Most student-athletes received academic adjustment recommendations. Symptom and neurocognitive measures may aid clinicians in decision-making about academic adjustments.

Competing interests

Study funded in part by a research grant from the National Operating Committee on Standards for Athletic Equipment.

Ms. Fonseca is employed at the study setting.

Ms. Phillips is employed at the study setting.

Dr. Bloom is employed at the study setting.
Simulations of recently observed shear shock wave physics amplify local brain accelerations by a factor of 40 in head drop experiments – future implications for concussion
Authors: Campbell Kody R , Mihalik Jason P , Tripathi Bharat B , Espindola David , Pinton Gianmarco F
Published: November 2017

Objective

Shear waves that travel in the brain are highly nonlinear and can develop into shock waves. This newly observed phenomenon could have implications for concussion. Our objective was to determine the effect of the brain’s nonlinear shear wave propagation behaviour on laboratory acquired head impact kinematics through numerical simulations.

Design

Head impact kinematics, obtained from controlled laboratory drops to cadaveric human heads, provided inputs to a one dimensional simulation of a cubically nonlinear shear wave equation solved with a piecewise parabolic method. Of the 292 drops, 125 caused significant motion about one axis. We assumed this would provide optimal conditions to create shears waves. The nonlinear and attenuation properties for the simulation were experimentally measured in fresh porcine brains with high frame-rate ultrasound.

Setting

Labratory.

Subjects

None.

Intervention

Independent variable – Nonlinear and attenuating properties of the brain.

Outcome measures

Peak Linear Tangential Acceleration (PLTA) measured at the skull was compared to the max PLTA acquired from the simulation for each of the 125 trials.

Results

There were 17 cases where nonlinearity overcame attenuation and resulted in the PLTA amplifying as high as 40 times the initial PLTA at the skull.

Conclusions

Our models of previously unobserved shear shock wave physics strongly suggest that nonlinearity is a first order parameter in brain kinematics and may have a fundamental influence on brain injury. Expanding these nonlinear simulations to three dimensions could better link head impact kinematics collected in the field with concussion risk and other head injuries.

Competing interests

Head drop data were obtained in collaboration with Drs. Cameron “Dale” Bass and Jason F. Luck (Duke University, USA) and Dr. David B. Camarillo (Stanford University, USA)

None.
The impact of concussion on brain adaptation: the use of prism glasses as a novel diagnostic tool
Authors: Little Elaine C , Emery Carolyn A , Schneider Kathryn , Dukelow Sean P
Published: November 2017

Objective

To evaluate brain adaptation following concussion. Do youth with a history of previous or acute concussion require more ball throws to land on or near a target, when wearing prism glasses (bend light to the left by 15˚), than youth with none?

Design

Cross-sectional study.

Setting

Sport Injury Prevention Research Centre, Alberta, Canada.

Participants

Ice hockey players: 21 with acute concussion [(17 males), mean age 13.8 (95% CI: 13.4, 14.2), median number of days since concussion 4 (range 2–11)], 40 reporting previous concussion(s) [(33 males), mean age 13.4 (95% CI: 13.1, 13.7), median number of days since last concussion 620 (range 90–1560)], and 40 with no concussion history [(36 males), mean age 12.9 (95% CI: 12.5, 13.2)].

Independent variable

Lifetime concussion history (yes/no) or acute concussion (<10 days).

Dependent variable

Number of throws for brain adaptation.

Main results

A significant concussion effect was identified across groups [F(2,98)=26.17, p<0.001]. Post-hoc analyses showed a difference in the number of throws in players with no concussion history versus players reporting previous concussions [−4.700 (95% CI: −8.44, −0.96)] and acute concussions [−13.440 (95% CI: −17.89, −8.99)], as well as between previous history versus acute concussion groups [−8.740 (95% CI: −13.19, −4.29)].

Conclusions

Concussion history and acute concussion appears to negatively impact brain plasticity in youth. They do not adapt as well as individuals with no concussion history. Our results support the use of a prism adaptation paradigm for identifying/quantifying short and long-term neurologic impairments in youth following concussion.

Competing interests

None.
Using neurophysiological measures to assess concussion. a case control study in one player
Authors: Cohen Adrian , Doug King , Alan Pearce J
Published: November 2017

Objective

case study presents data using multimodal assessment using impact sensors, oculomotor function and transcranial magnetic stimulation (TMS) to quantify neurophysiological changes in the acute period following concussion.

Design

Case control study.

Participants

Over one season, we evaluated a male rugby union player (age: 29 years; prior concussions: 1; last concussed >120 months) for head impacts using impact sensors (X2 Biosystems, USA) and oculomotor function (King-Devick test).1TMS (MagVenture, Denmark) protocols utilised previously published methods for concussion studies2,3with data compared to our normative database of age-group controls (33 males; mean age: 28.6±3.9 years).

Intervention

Any impact that resulted in a concussion, confirmed by the team doctor, required post-match testing utilising the King-Devick test and follow up testing for TMS at 5 d and 12 d.

Outcome measures

Time and errors completing the King-Devick test. TMS measures included latency (TMS stimulus to evoked potential onset ), evoked potential amplitude, and intracortical inhibition (TMS onset to return of uninterrupted electromyography activity).

Main results

An impact of 60.7 g/17, 114.1 rads/s2revelead a decreased King-Devick performance of 3.8 s. At 30 d King Devick remained below pre concussion baseline. Compared to controls, TMS revealed increased intracortical inhibition duration of 20.6 ms at 5 d post concussion, and returning to baseline/control levels by 12 d.

Conclusions

This novel case study demonstrates the value of using multimodal measurements in the assessment of concussion and return to play decisions.

Competing interests

None.

AJP is supported, in part, by a research grant by the Australian Football League.
Characteristics of paediatricpediatric concussion patients utilisingutilizing emergency department services prior to initial concussion clinic evaluation
Authors: Maio Valerie De , Register-Mihalik Johna , Herzog Mackenzie , Fonseca Janna , Phillips Kristen , Josh Bloom O
Published: November 2017

Objective

To evaluate characteristics of paediatric concussion patients utilising the emergency department (ED) prior to initial concussion clinic evaluation.

Design

Prospective cohort.

Setting

Clinics of an American urban/suburban family practice (12/2014–04/2015).

Subjects

Consented concussion patients 8–18 years presenting to clinic within 3 days of injury (n=195; age=14.3, SD=2.1 years; female=42.3%).

Intervention

Participants completed a systematic evaluation at initial clinic visit and survey at 4-6 weeks (73.8% follow-up). Criterion variables included demographics, prior head injury, time of injury (TOI) factors, total symptom severity, Immediate Postconcussion Assessment and Cognitive Test (ImPACT) composites, one-month persistent symptoms, one-month Paediatric Quality of Life (PedsQL).

Outcome measures

ED visit before clinic evaluation (yes/no) served as the dependent variable.

Results

ED visits were reported for 12.8% (n=25) of participants. Amnesia (36.0% vs. 10.1%; p<0.001), loss of consciousness (LOC) (20.8% vs. 6.7%; p=0.021), confusion (40.0% vs. 20.0%; p<0.0255), difficulty remembering (52.0% vs. 26.5%; p<0.0091), paresthesias (16.0% vs. 4.7%; p<0.0282), and CT imaging (60.0% vs. 0.6%; p<0.0001) were greater for the ED group. Initial symptom severity and ImPACT composite scores, and one-month outcomes of persistent symptoms and PedsQL, were no different for the ED group.

Conclusions

Paediatric patients presenting to concussion clinic with 72 hours of injury who first visited an ED, have more dramatic symptoms at the TOI, yet do not appear to have any worse initial symptom severity, ImPACT scores, or one-month persistent symptoms or PedsQL than those who presented first to clinic. Future study should evaluate these relationships in larger samples.

Competing interests

The current study is funded in part by the National Operating Committee on Standards for Athletic Equipment.

Ms. Fonseca is employed at the study setting.

Ms. Phillips is employed at the study setting.

Dr. Bloom is employed at the study setting.
Role of sport-related concussion on academic achievement among youth athletes
Authors: Russell Kelly , Selci Erin , Rozbacher Adrian , Ellis Michael
Published: November 2017

Objective

Determine change in report card grades in youth after sustaining an acute sport-related concussion.

Design

Prospective case-series.

Setting

Paediatric, multi-disciplinary concussion.

Participants

48 youth athletes (mean age 14.3; SD: 0.9; male: 57.6%) who sustained a sport-related concussion during the school year. Overall, 3 youth were lost to follow-up and 12 youth submitted only one report card.

Interventions (or assessment of risk factors)

Subsequently developing Post-Concussion Syndrome (PCS: symptomatic after 30 days), initial concussion severity (Post Concussion Symptom Scale), self-reported concussion history, sex, age, and academic accommodations during recovery.

Outcome measures

The report card immediately before the concussion and the report card immediately after medical clearance were collected. Pre-concussion and post-concussion overall and core grade-point average was calculated from report cards. Core grade-point average (GPA) included math, sciences, social studies, English, and foreign languages.

Main results

Overall GPA was 82.9% (SD 8.5%) pre-concussion and 82.7% (SD 8.0%) after concussion recovery (difference: −0.2%, 95% CI: −1.6%, 1.1%). Core GPA was 80.0% (SD 10.1%) pre-concussion and 79.4% (SD 10.4%) after concussion recovery (difference: −0.6%, 95% CI: −2.8%, 1.6%). There were no significant differences in overall or core GPA when stratified by sex, age, initial concussion severity, previous concussion history, receiving adequate school accommodations during recovery, or subsequently developing PCS.

Conclusions

There were no statistically or clinically significant changes in overall or core GPA during concussion recovery. Further research is needed to determine if there are more subtle changes in academic performance during the recovery process.

Competing interests

None.
The effects of prior concussion and contact sport participation on the brain
Authors: Churchill Nathan , Hutchison Michael , Schweizer Tom A
Published: November 2017

Objective

there is currently limited information on the neurobiological effects of contact sport participation, and interactions with history of concussion. The goal of this study is to examine the interactions between history of concussion and contact sport participation, using biomarkers of cerebral metabolites, brain function, and white matter microstructure.

Design

cross-sectional study.

Setting

sport medicine clinic, affiliated with inter-university sport program (secondary care).

Participants

43 athletes without concussion in the past 6 months were recruited, including 22 athletes without prior concussion (13 non-contact, 9 contact; 11 female) and 21 athletes with a history of concussion (13 non-contact, 8 contact; 11 female).

Outcome measures

Magnetic Resonance Imaging (MRI) was used to measure brain biomarkers: MRI spectroscopy to evaluate cerebral metabolites; functional MRI to assess brain function; diffusion tensor imaging for white matter microstructure.

Main results

athletes in contact sports with prior concussion showed significant differences in brain structure and function, relative to athletes in non-contact sports, and those in contact sports without prior injury. This included significantly elevated glutamate ratios, decreased functional connectivity of the visual and motor systems, and increased fractional anisotropy of white matter.

Conclusions

This study provides the first multi-modal MRI data showing altered brain structure and function in athletes with a history of concussion and interactions with contact sport participation. These findings provide strong preliminary evidence that athletes in contact sports may be more vulnerable to the long-term effects of sport concussion.

Competing interests

None.
Attention problems as a risk factor for concussion in youth ice-hockey players
Authors: Gerschman Tommy , Schneider Kathryn , Yeates Keith , Brooks Brian L , Kipps Courtney , Emery Carolyn
Published: November 2017

Objective

To examine attention problems in youth ice-hockey players as a risk factor for concussion.

Design

Secondary analysis of two prospective cohort studies.

Setting

Ice-rinks and Sport Medicine Centres in two Canadian cities over three ice-hockey seasons (2011/12, 2012/13, 2014/15).

Assessment of risk factors

Self-report of formal diagnosis of attention or learning disorders were collected on previously validated preseason baseline questionnaires by all participating players. Parents and players completed the Behaviour Assessment System for Children (BASC-2), which includes inattention and hyperactivity scales.

Participants

2,364 Canadian ice-hockey players (11–17 years old, 87% male).

Outcome measures

A previously validated prospective injury surveillance system was used. All suspected concussions were referred to the study physician for confirmation of diagnosis. Concussion risk ratios (RR) were estimated, including stratification by known risk factors.

Results

One-hundred ninety-two of 2,215 players (9%) self-reported attention and/or learning disorders at baseline. Overall, 256 players (11%) sustained one or more concussions during a season. Players identified as “at-risk” for attention-deficit hyperactivity disorder (ADHD), based on BASC-2 T-scores (inattention and/or hyperactivity scale) greater than 60, had a greater risk of concussion during the season based on child report [RR=1.51 (95% CI 1.13–2.04)] and parent report [2.97 (95% CI 1.65–5.34)]. In players with no history of previous concussion, the RR based on child report was 1.88 (95% CI 1.22–2.90) and based on parent report was 5.03 (95% CI 2.45–10.29).

Conclusions

Ice-hockey players identified as “at-risk” for ADHD on the basis of baseline BASC-2 scores are at a greater risk of concussion.

Competing interests

None.
Baseline symptoms are associated with post-concussion symptom frequency and severity in college and high school athletes
Authors: Teel EF , Wasserman EB , Register-Mihalik JK , Mihalik JP
Published: November 2017

Objective

To determine the association between baseline symptoms and symptom frequency and severity one day post-concussion in college and high school athletes.

Design

Prospective cohort.

Setting

USA colleges (n=26) and high schools (n=210).

Subjects

Concussed individuals (n=375; 314 males; 61 females) recruited from a baseline cohort (N=8,905).

Intervention

Baseline presence or absence for each of the 20 items on a Graded Symptom Checklist (GSC).

Outcome measures

GSC symptom frequency and severity one day post-concussion.

Results

Individuals with baseline headache (χ2(1)=10.98;P<0.001), fatigue (χ2(1)=6.06;P=0.014), sleeping more than usual (χ2(1)=16.90;P<0.001), blurred vision (χ2(1)=20.48;P<0.001), light/noise sensitivity (χ2(1)=4.67;P=0.031), and mental fogginess (χ2(1)=6.08;P=0.014) reported these symptoms at a higher frequency post-concussion. Subjects reporting the following baseline symptoms had greater severity of the same symptom post-concussion: headache (Presence: median=2; IQR=1–4; Absence: median=2, IQR=0–3;P=0.004), fatigue (Presence: median=1; IQR=0–3; Absence: median=0, IQR=0–2;P=0.017), sleeping more than usual (Presence: median=1, IQR=0–3; Absence: median=0, IQR=0–0;P<0.001), blurred vision (Presence: median=1; IQR=0–2; Absence: median=0, IQR=0–0;P<0.001), sensitivity to light and noise (Presence: median=1, IQR=0–3; Absence: median=0, IQR=0–1;P=0.010), and fogginess (Presence: median=2, IQR=0–3; Absence: median=0, IQR=0–1;P=0.002). No other symptoms at baseline were associated with post-concussion symptom frequency or severity (P>0.05).

Conclusions

Athletes reporting baseline symptoms, particularly those in physical and sleep-related domains, were more likely to report a higher frequency and severity of these same symptoms one day post-concussion. Understanding factors influencing post-concussion symptom recovery may inform clinical decision-making and offer selection criteria for appropriate active recovery strategies.

Competing interests

None.