bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative behaviourbehavior modification strategies to reduce concussion risk in high school american football athletes
Authors: Wasserman Erin B , Mihalik Jason P , Campbell Kody R , Combs Patricia , Fraser Melissa A , Grand Erin , Nocera Maryalice , Register-Mihalik Johna K , Guskiewicz Kevin M , Marshall Stephen W
Published: November 2017

Objective

To improve tackling and blocking techniques to reduce concussion in high school American football players, and to evaluate the program’s feasibility and acceptance.

Design

Clustered quasi-experimental study.

Setting

High schools.

Participants

Varsity American high school football players on three teams (two intervention; one control).

Interventions

All players wore in-helmet head impact accelerometers. “High-risk” intervention team players were selected and attended clinician-coach-player mentoring sessions designed to change playing technique. Accelerometer data were used for “high-risk” selection and during mentoring sessions to reinforce the technique-driven intervention.

Outcome measures

The change in top-of-head impacts and impacts with peak linear acceleration>60 g was compared between intervention and control subjects using linear risk models. Coaches and players completed post-season exit surveys.

Main results

Ninety-seven players (70 intervention; 27 control) participated. Thirteen (19%) intervention players were identified as “high risk” and received mentoring. The mentored players’ high magnitude impacts (percent>60 g) in practices dropped 1.9 percent from pre-intervention to post-intervention. There was no change in non-mentored players. In post-season surveys, mentored players “strongly agreed” (56%) or “agreed” (44%) that the study improved their playing behaviours. Among intervention team coaches, three (43%) thought the study was “very effective” in changing football player behaviours about safe play, and the remaining four (57%) thought it was “effective.”

Conclusions

There is growing concern head impact frequency and severity may result in neurological issues for some athletes later in life. If head impact frequency and severity can be reduced through behavioural intervention, this can have a great public health impact.

Competing interests

This study is funded by a grant from the National Centre for Injury Prevention and Control (Grant #R49CE002479).
Quantification of postural control deficits in patients with recent concussion: an inertial-sensor based approach
Authors: Doherty Cailbhe , Caulfield Brian , Ryan John , Komaba Yusuke , Inomata Akihiro , Zhao Liang
Published: November 2017

Objective

To quantify postural control ability in a group with concussion compared with a ‘healthy’ control group.

Design

Case-control study.

Setting

University Biomechanics Laboratory.

Participants

Fifteen concussion patients (4 females, 11 males) and a group of fifteen age- and sex- matched controls. Participants were excluded if they had any: lower extremity injury that may affect gait; history of cognitive deficiencies; history of ≥3 previous concussions; loss of consciousness following the concussion for >1 minute; a previously documented concussion in the previous year

Independent variable

Group; Task (3 stance variants of the Balance Error Scoring System [BESS])

Outcome measures

Sway area as computed using a force-plate and sway volume as computed from an accelerometer placed on the sacrum during performance of the BESS.

Main results

Concussed patients exhibited increased sway area (1500 mm2[95% CI: 900 to 2000 mm2] vs 650 mm2[95% CI: 520 to 780 mm2] p=0.02) and sway volume (9.5 m3s–6[95%CI: 8 to 20 m3s–6] vs 2.80 m3s–6[95% CI: 1.8 to 3.6 m3s–6]) in the bilateral stance position of the BESS. The sway volume metric also had excellent accuracy in identifying task ‘errors’ (tandem stance: 95% CI: 80–96%, p<0.001; unilateral stance: 95% CI: 85–95%, p<0.001).

Conclusions

Individuals with concussion display increased postural sway during bilateral stance. The sway volume that was calculated from the accelerometer data not only differentiated a group with concussion from a healthy control group, but successfully identified when task errors had occurred. This may be of value in the development of a pitch-side assessment system for concussion.

Competing interests

None.
Age and sport are associated with higher odds of playing through a concussion and delayed removal from play
Authors: Zuckerman Scott L , Kuhn Andrew W , Yengo-Kahn Aaron M , Kerr Zachary Y , Totten Doug J , Solomon Gary S , Sills Allen K
Published: November 2017

Objective

To elucidate situational factors and individual characteristics related to playing through a sport-related concussion (SRC) and delayed removal from play.

Design

Retrospective cross-sectional analysis.

Setting

A single comprehensive sports-concussion centre.

Participants

250 middle school, high school, and collegiate athletes who sustained an SRC and presented to a regional concussion center between 2011 and 2015.

Intervention

Standardised in-depth phone interviews.

Outcome measures

Gender, race, age, competition level, sport, concussion history, practice/game, and collision awareness, among other variables, were incorporated into a multivariate regression model to determine if any of these variable could significantly predict the likelihood of playing through a sport-related concussion versus immediate removal from play.

Main results

Age (p=0.047) and sport (p=0.006) were both significantly associated with playing through a concussion. For every additional year of age, the odds of playing through an SRC decreased by 1.32 [95% CI: 1.00–1.72]. Football players were much more likely to attempt to “play through” a concussion when compared to baseball/softball, basketball, cheerleading, lacrosse, rugby and volleyball athletes (OR 5.41 [95% CI: 1.62–18.2] to 71.4 [95% CI: 4.93–1,000] times the odds of playing through an SRC for various sports, with all differences reaching statistical significance).

Conclusions

Younger age and certain sports (football) were significantly associated with delayed removal from play after a SRC in middle school, high school, and collegiate athletes. Given these results, sports medicine practitioners may be better able to identify situational and individual characteristics of athletes who may be more likely play through a SRC.

Competing interests

GS Solomon receives consulting fees from the Tennessee Titans (NFL), the Nashville Predators (NHL), and the athletic departments of several universities, all fees paid to institution. In addition he is a member of the ImPACT Scientific Advisory Board, and receives reimbursement for expenses to board meetings. AK Sills is a consulting physician to the Nashville Predators (uncompensated) and also serves as an unaffiliated neurotrauma consultant for the NFL. SL Zuckerman, AW Kuhn, AM Yengo-Kahn, ZY Kerr, DJ Totten, report no conflicts of interest.
Blue card: referees’ perspectives of a rugby union concussion recognition and management programme
Authors: Sullivan John , Collins Kyal , Grey Andrew , Handcock Phil
Published: November 2017

Objective

The Northland (New Zealand) Rugby Union developed an innovative concussion recognition and management programme (Blue Card) as part of its player welfare responsibilities for club (community) players. The referee is empowered to issue a Blue Card (BC) to any player they suspect of being concussed, thus removing them from the game. The purpose of this descriptive study was to investigate the referees’ perspectives on having this added responsibility, and whether this detracted from their enjoyment of refereeing.

Design

Cross-sectional survey.

Setting

Northland Rugby Union headquarters

Participants

Twenty-one amateur male referees who officiated in club-level rugby matches covered by the Northland Rugby Union Blue (NRUBC) programme during the 2014 season volunteered to participate.

Outcome measures

Custom-designed survey instrument using both open and closed questions.

Main results

The referees had between 2 and 35 (mean=12.1) seasons of refereeing experience with 81% (17/21) claiming a good or average knowledge of concussion. The majority (20/21) reported that they had sufficient training for their expanded role. Two thirds (14/21) of the respondents did not think that the additional responsibility impacted on their refereeing satisfaction. Over the season nine (9) BCs were issued by 7 of the participating referees, with 5 indicating that they were “very confident” in their decision.

Conclusions

The referees indicated that they were well prepared to handle the added responsibility as on-field concussion gatekeepers, and this role did not detract from their enjoyment of refereeing the game. Additional insight into how the NRUBC programme is received by players, teammates and their families, needs investigation.

Competing interests

S.J Sullivan, A Gray and P Handcock: None.

K Collins was involved in the development of the Northland Blue Card Programme but was not involved in the data analysis.

None.
Concussion diagnosis: the king-devick test in the canadian football league
Authors: J Naidu Dhiren , Mrazik Martin
Published: November 2017

Objective

To conduct a sensitivity analysis of the King-Devick (K-D) test in professional football.

Design

Prospective cohort.

Setting

Professional football.

Participants:

269 professional football players from the Canadian Football League (CFL). There were 24 concussions to analyse.

Intervention

The K-D test was added to the existing CFL concussion protocol (medical and SCAT3). All participants completed K-D assessments at baseline, at the time of injury/concussion (TOI), and at medical clearance prior to return to play (RTP). 20 controls were re-tested post-baseline.

Outcome measures

K-D scores were analysed to construct a sensitivity analysis.

Main results

TOI K-D results were significantly higher (mean=50.21, range: 35.4–107.4) than baseline K-D results (mean=44.3, range 28.4–66.4; p<0.01). TOI K-D results yielded 94% sensitivity and 80% specificity for diagnosing concussions. Four groups emerged from the TOI data. In Group 1, 4/4 were asymptomatic within 24 hours and scores were better (lower) than baseline; Group 2 were asymptomatic within 72 hours and 8/9 had abnormal (poorer) scores; Group 3 were asymptomatic within 11 days and 5/5 had abnormal scores. Group 4 were symptomatic by season’s end and 4/4 had abnormal scores. 18/18 players who RTP had better K-D scores than baseline prior to RTP.

Conclusions

The K-D test proved to be useful for concussion diagnosis. Interestingly, the players in Group 1 had normal TOI K-D scores and were asymptomatic in <24 hours. More research is needed and the CFL will continue this next season.

Competing interests

None.
Receded near point of convergence and gait are associated after concussion
Authors: Howell David R , O’Brien Michael J , Raghuram Aparna , Shah Ankoor S , Meehan William P
Published: November 2017

Objective

To examine post-concussion gait among patients with and without receded near point of convergence (NPC) and uninjured controls.

Design

Prospective observational study.

Setting

Regional sport-concussion clinic.

Participants

Thirty-one patients presented 10.1 [95% CI=8.1, 12.1] days post-concussion (57% female, age=16.5 [15.4, 17.7]); 38 controls were tested (55% female, age=15.5 [13.6, 17.4]). Participants completed symptom, NPC, and single/dual-task gait assessments. Exclusion criteria were a current lower extremity injury or diagnosed learning disability.

Intervention

The effect of group (receded NPC, normal NPC, control) and task (single/dual) were evaluated via ANOVA. NPC and gait correlations were calculated.

Outcome measures

NPC was the patient-reported diplopia point while a fixation target moved toward the nose. Receded NPC was >5 cm from the tip of the nose. Three inertial sensors quantified gait; variables included average gait speed, cadence, and stride length.

Results

Nineteen concussion patients presented with receded NPC, 12 did not. Symptom severity was not significantly different between groups (27.1 [18.6, 35.6] vs. 26.3 [17.1, 35.5]). Those with receded NPC exhibited slower average gait speed (1.02 [0.93, 1.11] m/s vs. 1.19 [1.14, 1.24] m/s, p<0.001) and shorter stride lengths (1.11 [1.05, 1.18] m vs. 1.27 [1.23, 1.31] m, p=0.001) than controls. Near NPC and single-task gait speed were moderately correlated (ρ=−0.54, p= 0.002).

Conclusions

Adolescents with receded NPC post-concussion exhibited significant gait-related alterations compared to healthy controls; those with normal NPC did not. Vergence and gross motor system dysfunction may be interrelated following concussion and may provide useful information to post-concussion evaluations.

Competing interests

Dr. Meehan receives royalties from ABC-Clio publishing for the sale of his book, Kids, Sports, and Concussion: A guide for coaches and parents, and royalties from Wolters Kluwer for working as an author for UpToDate. He is under contract with ABC-Clio publishing for a future book entitled, Concussions, and with Springer International publishing for a future book entitled, Head and Neck Injuries in Young Athletes. His research is funded, in part, by a grant from the National Football League Players Association and by philanthropic support from the National Hockey League Alumni Association through the Corey C. Griffin Pro-Am Tournament. Dr. O’Brien receives royalties from Wolters Kluwer for working as an author for UpToDate. He is under contract with Springer International publishing for a book entitled, Head and Neck Injuries in Young Athletes. Drs. Howell, Shah, and Raghuram have no conflicts of interest to report.
Recognition and knowledge of on-field management of concussion amongst english professional, semi-professional and amateur rugby union referees
Authors: Gallagher Tom , Mias Ed , Kipps Courtney
Published: November 2017

Objective

to investigate the knowledge and practice of Rugby Union referees regarding the recognition and management of concussion in English professional and semi-professional rugby.

Design

email survey questionnaire.

Setting

English Rugby Union Premiership, Championship and National Leagues.

Participants

All 180 actively practicing referees in England in the Premiership, Championship and National Leagues.

Outcome measures

Actual and perceived knowledge of concussion, and subjective confidence in diagnosing concussion.

Main results

22 referees with an average age 34.77 years (Range 26-49 SD 6.13) and returned surveys. The referees’ level of officiating ranged from Premiership (Level 1) to regional games (Level 8) with the highest proportion of referees officiating at Level 1 (31.80%). A high percentage of referees recognised functional disturbances including loss of balance (90%), slurred speech (73%), dizziness (95%) and blurred vision (100%) as signs of concussion. 59.09% rated their knowledge of concussion as average and 18.18%% good or excellent. Overall, 72% of referees felt they could subjectively diagnose concussion, the professional referees were more confident in diagnosing a concussion versus the amateur referees.

Conclusions

Referees generally have a good knowledge of concussion and its management although 54.54% have had no previous education. The majority wanted to learn more on the subject (90.90%) but the methods which they are currently using to learn are varied and not standardised. Practical group sessions (59.09%) and online resources (45.45%) were recognised as the most popular method of learning. Further education regarding recognition and on-field management of concussion is recommended for rugby union referees. Future studies should focus on participant information retention after using such resources as HeadCase.

Competing interests

None.
Acute rest does not predict symptom recovery in collegiate student athletes
Authors: Buckley Thomas A , Munkasy Barry A , Clouse Brandy P , Evans Kelsey M
Published: November 2017

Objective

To assess the effect of acute cognitive and physical activity level and sleep on concussion recovery.

Design

Prospective.

Setting:

College sports medicine.

Participants:

Forty-one college student athletes (51.2% Female; Age: 19.6 + 1.2 years) diagnosed with sports-related concussions.

Interventions

The independent variables were the participant’s self-reported physical and cognitive activity levels (1–5 based on Majerske) and the number of hours slept the first two days post-concussion.

Outcome measures

The dependent variables were the number of days until the participant 1) self-report asymptomatic and 2) had full return-to-participation which required achieving baseline values on balance, cognitive, neuropsychological testing and completing a progressive return to activity protocol. The independent variables (activity levels and sleep) were used as predictors of recovery with a linear regression.

Main results

The participants were asymptomatic 4.7 + 2.8 (95% CI: 3.8–5.5) days and returned-to-participation 13.0 + 4.2 (95% CI: 11.8–14.3) days post-concussion. Participants reported a mean 7.8 + 1.9 hours of sleep per night and low physical (1.4 + 0.7) and cognitive (2.7 + 1.4) activity levels. There were no significant correlations and the overall model did not predict days until asymptomatic (F=1.224, P=0.315) or return-to-participation time (F=0.036, P=0.991). None of the independent variables were significant predictors.

Conclusions

The activity levels and reported sleep in the first two days post-concussion did not predict recovery time. This finding is consistent with emerging literature suggesting acutely restricting activity may not improve concussion recovery time. Future studies should utilise sleep logs and objectively measure activity levels.

Competing interests

None.
Botulinum toxin a for adolescents with persisting post-concussion headaches: a case series
Authors: Purtzki Jacqueline , Chan Catherine
Published: November 2017

Objective

To present safety and tolerability of treating persistent post-concussive headaches with botulinum toxin A (Botox) in adolescents.

Design

Retrospective case series.

Setting

A tertiary rehabilitation hospital interdisciplinary outpatient concussion clinic for adolescents aged 12–18 years.

Participants

Seven patients ages 15–18 with persistent post-concussion headaches.

Interventions

1. Comprehensive assessment by an interdisciplinary rehab team. 2. Establishing the diagnosis of chronic daily headache disorder with 15 headaches per month, 8 of them meeting pediatric migraine criteria. Headache treatment included neck exercises, physiotherapy, CBT, mindfulness, oral prophylactic and abortive migraine medications as well as Botox. Patients selected had prolonged debilitating headaches, had failed other treatment options, and/or had specific circumstances precluding use of other treatment options, were unable to attend school, tolerate daily activities. 3. Discussion of potential side effects of Botox, complications of injection, review of current literature evidence. Verbal consent obtained.

Clinical monitoring of adverse events of injection, side effects of Botox, effect on daily activities and headaches.

Main results

There were no adverse events related to the injection of Botox. Some patients experienced a transient flare up of headaches after injection. All patients reported that injections and post-injection side effects were tolerable. Reduction in headaches was variable.

Conclusions

Based on this small clinical sample of adolescents with severe persistent post-concussion headaches, Botox appears to be a well-tolerated and safe treatment option. Prospective, RCT studies are required to confirm this preliminary clinical impression.

Competing interests

None.
Efficiency of an active rehabilitation intervention in a slow-to-recover paediatric population following a sport-related concussion
Authors: Fait Phil , Imhoff Sarah , Carrier-Toutant Frédérike , Geneviève Boulard
Published: November 2017

Objective

The aim of this study was to identify whether the addition of an individualised Active Rehabilitation Intervention to standard care influences recovery of young patients who are slow to recover following a sport-related concussion and remain symptomatic at rest.

Design

Quasi-experimental, prospective study Setting: Interdisciplinary private concussion clinic

Subjects

Fifteen participants aged 15±2 years.

Intervention

Standard care and an individualised Active Rehabilitation Intervention which included: 1) low- to high-intensity aerobic training; 2) specific coordination exercises; and, 3) balance exercises.

Outcome measures

List of symptoms before and after the intervention, duration of symptoms, adherence to the individualised exercice program.

Results

The Active Rehabilitation Intervention lasted 49 (SD=17 days) days. The duration of the intervention was correlated to self-reported adherence (x=84.64 19.63%, r=−0.792, p<0.001). The average postconcussion symptom inventory (PCSI) score went from a total of 36.85±23.21 points to 4.31±5.04 points after the intervention (Z=−3.18, p=0.001).

Conclusions

A progressive sub-maximal Active Rehabilitation Intervention may represent an important asset in the recovery of young patients who are slow to recover following a sport-related concussion.

Competing interests

Phil Fait: Co-owner of the Cortex Mdecine et Radaptation clinic Sarah Imhoff, Frdrike Carrier-Toutant, Genevive Boulard: None.
Serum neurofilament light concentration increases following a season of american football
Authors: Wallace Colin , Henrik Zetterberg , Kim Henriksen , Paul van Donkelaar
Published: November 2017

Objective

To examine neurofilament light (NF-L), a microtubule-associated protein widely regarded to be central nervous system (CNS) specific, concentrations in serum prior to and following a season of contact (American football) and non-contact (cross-country running) in elite, collegiate-aged athletes.

Design

Prospective cohort.

Setting

Laboratory.

Participants

13 male American football athletes (19±1.2 years) and 11 cross-country runners (20±1.9 years).

Intervention

Pre- and post-season blood samples were obtained from all participants and spun at 2000 g for 10 minutes to extract serum. NF-L was detected through the isolation of individual immunocomplexes on pragmatic beads using standard ELISA reagents. The beads were then trapped in single-molecule, femtolitre-sized wells, allowing for a digital readout of each individual bead. The digital nature of this technique allows an average of 1000x sensitivity increase over conventional assays.

Outcome measures

Analysis of pre- and post-season serum samples provide NF-L concentrations.

Results

Serum samples from American football players showed a significant increase (p=0.04) from pre-season NF-L serum concentrations (95% CI: 6.51 – 9.19 pg/mL) to post-season (95% CI: 7.08 – 11.70 pg/mL). Serum NF-L concentrations in cross-country runners showed no change (p=0.57) from pre-season (95% CI: 5.05 – 6.94 pg/mL) to post-season (95% CI: 5.05 – 6.88 pg/mL).

Conclusions

Experiencing repetitive subconcussive head-trauma throughout a season of American football elevates serum NF-L concentrations. This finding indicates multiple head-impacts may lead to CNS axonal damage.

Competing interests

None.
Spinal control is related to concussion in professional footballers
Authors: Leung Felix , Hides Julie A , Franettovich Smith Melinda M , Mendis Dilani M , Smith Nigel A , Cooper Andrew J , Treleaven Julia , Choy Nancy Low
Published: November 2017

Objective

To examine whether physical measurements of the sensorimotor system predict concussion incurred by footballers.

Design

Prospective cohort study.

Setting

Australian professional sport setting.

Participants

Fifty-three rugby union and rugby league players.

Assessment of risk factors

Physical measurements including balance (sway across six test conditions), vestibular function (assessments of oculo-motor and vestibular ocular reflex) and spinal control (cervical joint position error and trunk muscle size and contraction ability) were performed during the preseason.

Outcome measures

Concussion injuries during the season were diagnosed and recorded by club medical staff.

Results

Age, height, weight, and years playing football were not associated with concussion in the season (p=0.43, 0.43, 0.19, 0.25). Preseason cross-sectional area of the multifidus muscle at the L5 vertebral level was 10% smaller in players who went on to sustain a season concussion compared to those who did not: mean difference (95% confidence interval) 1.0 cm2(0.1 cm2to 1.9 cm2), p=0.031. This difference in size was moderate (effect size 0.7) and exceeds the minimal detectable change of 0.4 cm2. There were no significant differences observed for the other measures, p>0.05.

Conclusions

Optimal spinal control is likely to be a key requirement in a physically demanding sport such as football. The multifidus is one of the muscles crucial for spinal control, and our findings report this measure to be predictive of footballers sustaining a concussion. This novel finding provides preliminary evidence that warrants further investigation as to the possible importance of spinal control in prevention programs

Competing interests

None.
Association between concussion history and knowledge among italian youth soccer athletes
Authors: Filali Naji , McLeod Tamara Valovich , Bacon Cailee Welch , Bellini Gianandrea , Amaddeo Paolo , Cornali Claudio
Published: November 2017

Objective

To compare concussion-based knowledge between Italian youth soccer athletes who reported a previously diagnosed concussion or concussion-like symptoms and those without prior concussion history.

Design

Cross sectional.

Setting

Self-reported survey.

Subjects

Male soccer athletes (n=766, age=16.9 ± 1.3 years, experience=6.6 ± 3.9 years) from 25 club teams across three professional leagues in Italy.

Intervention

The independent variables studied were diagnosed concussion group (prior diagnosed concussion vs. no diagnosed concussion) and self-reported concussion symptom group (experienced concussion-like symptoms vs. no concussion-like symptoms).

Outcome measures

The dependent variables were total knowledge scores, measured through accurate endorsement of symptoms and responses to true and false prompts. Independent t-tests were used to determine group differences.

Results

45 (6%) respondents indicated they sustained a physician-diagnosed concussion. The mean number of diagnosed concussions was 0.065±0.3 (range 0–3). 198 (26.2%) respondents indicated they had experienced concussion-like symptoms. The mean frequency of self-reported concussion-like symptoms was 0.54±1.3 (range: 0–15). There were no significant differences in concussion symptom knowledge (P=0.616, 13.9±2.0 vs. 14.1±2.2) or true and false knowledge (P=0.390, 10.7±1.8 vs. 10.4±1.7) between the group with a previously diagnosed concussion compared to the one without. There were also no significant differences in concussion symptom knowledge (P=0.499, 14.2±2.1 vs 14.1±2.2) or true and false knowledge (P=0.256, 10.5±1.6 vs. 10.4±1.8) between the group that had experienced concussion-like symptoms compared to the group that had not.

Conclusions

These results suggest the necessity for targeted knowledge-based interventions for youth athletes, especially for those who sustain and report concussions.

Competing interests

None.
Circulating microrna as novel early biomarker of concussion in elite athletes
Authors: SU Zhangjie , Di pietro Valentina , Davies David , Wang Michael , Evans Shaun , Hill Lisa , Grey Michael , Belli Antonio
Published: November 2017

Objective

This study aims to investigate the role of microRNAs in early and late assessments of concussed athletes. Our hypothesis is that expression of certain microRNAs is altered following concussion, and these microRNAs have the potential to become novel biomarkers for early detection and monitoring of concussion.

Design

Prospective observational case control study.

Setting

University research centre, single centre.

Participants

15 concussed athletes divided into 2 groups: Group A (n=9, assessed within a week post-concussion, median 4 days) and B (n=6, assessed over 2 weeks, median 31 days); and 8 age-matched healthy volunteers. Inclusion criteria: male/female elite athletes in contact sports (aged 18-40) who suffered concussion(s) in the games, and being symptomatic with normal neuro-radiological findings at enrolment.

Outcome measures

Levels of microRNAs (miR-21, miR-335, miR-425-5p, and miR-502) were measured in blood samples obtained from all participants.

Main results

miR425-5p was significantly down-regulated in Group A compared with Group B and healthy volunteers (grouping effect p=0.014; post hoc tests p=0.009 and 0.028, respectively). The level of miR425-5p correlated with the interval between assessment and concussion (r2=0.88, p<0.001). No differences were found in other microRNA assessed between the groups.

Conclusions

miR-425-5p is down-regulated in the early phase following sport concussion, and reaches normal levels in the late period, suggesting that it may be a unique microRNA signature for concussion. This makes miR-435-5p a promising candidate biomarker for early evaluation of concussion and monitoring of its recovery. Further longitudinal studies are on-going to establish the time course of miR-425-5p normalisation after concussion.

Competing interests

None.

Abstract 5 Figure 1
Concussion and mild traumatic brain injury (mtbi): towards a better integration of the two constructs
Authors: Frémont Pierre , Truchon Catherine
Published: November 2017

Objective

To analyse the potential ways to reunite the mTBI and concussion constructs in order to harmonise screening, diagnosis and management.

Design

Narrative review.

Setting

In Quebec, the initial management of concussions sustained in a sport or school-based setting falls under the authority of the Ministry of education and sports whereas the Ministry of health governs the clinical management of mTBI. The recent work of a task force on concussions in Quebec has emphasised the need to achieve a unified understanding and operationalization of the two constructs so that persons affected receive consistent information and care.

Main results

Sport and school-based concussion management is generally based on the Concussion In Sport Group definition whereas the Quebec health care system relies on the 5 diagnostic criteria proposed by the WHO task force in 2004. Although the 5 classification criteria of mTBI include normal values, the actual definition requires the presence of one or more abnormal criteria. In a public health care system, such a definition structures access to limited public resources. However unfavourable evolution can occur in the absence of phenomena such as LOC or PTA. Yet these cases represent a potentially serious health condition if proper identification and management is not initiated.

Conclusion

So far, sport, education and health care stakeholders in Quebec have agreed that the constructs of concussion and TBI must be revisited and better integrated. This process raises challenges and opportunities in terms of operationalization and management. Studies on prognostic indicators should guide this analysis.

Conclusion

Competing interests Pierre Frémont is chair of the Canadian Concussion Collaborative.

None.
Effect of a history of 3+ previous concussions on centre of pressure variables during quiet stance
Authors: Dierijck Jill K , Wright Alexander D , Bryk Kelsey , Smirl Jonathan D , Donkelaar Paul van
Published: November 2017

Objective

To determine the influence of a history of 3+ previous concussions on quiet stance.

Design

Retrospective cohort.

Setting

Laboratory.

Participants

Eighty-seven male (age range 17–22) contact-sport athletes (football and hockey) entered the study. Participants were recruited from the same sport teams and tested during the pre-season. Exclusion criteria: concussion in the prior 6 months, or history of 1 or 2 concussions. Forty-four met the inclusion criteria: thirty-one had no previous concussions, and thirteen had a history of 3+ concussions.

Interventions

Participants held quiet upright stance on a force plate (NDI True Impulse) with feet hip-width apart and hands on hips with eyes-open (1 min), and closed (1 min). Independent variables included condition (2) and concussion history (2).

Outcome measures

Root-mean-square displacement (RMSd), and mean velocity of centre-of-pressure (COP) in the anterior/posterior (AP) and medial/lateral (ML) directions.

Main results

Mixed ANOVA indicated a significant condition effect in ML-RMSd (p=0.015, 95% CI: 0.032–0.277) between eyes-open and eyes-closed conditions. ML mean velocity also displayed a significant condition effect (p=0.025, 95% CI: 0.025–0.358). In contrast to the effect of visual input, there was no main effect of concussion history on these metrics.

Conclusions

A history of 3+ concussions does not appear to result in long-term deficits controlling in quiet stance. Those ML variables were sensitive to condition and indicate that frontal plane COP movements may be more sensitive than those in the sagittal plane. These findings are important as a history of concussion does not appear to alter quiet stance balance control mechanisms.

Competing interests

None.
Interrelationships among neuroimaging biomarkers, neuropsychological test data, and symptom reporting in a cohort of retired national football league (nfl) players
Authors: Zuckerman Scott L , Kuhn Andrew W , Solomon Gary S , Sills Allen K , Casson Ira R
Published: November 2017

Objective

To assess interrelationships among neuroimaging findings with neurocognitive test performance and symptom endorsement in a cohort of retired professional (NFL) football players.

Design

Prospective cohort study.

Setting

Neurology clinic.

Participants

Forty-five retired NFL players.

Intervention

MRI scan assessment of cavum septum pellucidi, global mean score of Fractional Anisotropy (FA), and microhemorrhages.

Outcome measures

Nine neuropsychological tests and multiple symptom and depression scores. Associations among the three independent neuroimaging results with these outcome measures were assessed utilising Pearson’s, Spearman’s Rank, and Point-Biserial Correlations.

Results

The retirees reported an average of 6.9 (±6.2) concussions and 13.0 (±7.9) sport-related “dings” in the NFL. Assessment of cavum septum pellucidum yielded a negative finding in 10 subjects (22%), while 32 (71%) had a small, and 3 (7%) had a large one. Four (9%) of the subjects had microhemorrhages present and average FA mean was 0.459 (±0.035). Number of sport-related “dings” was correlated with an increased risk of microhemorrhages (r=0.305, p=0.042). The majority (50.8%) of the correlations obtained among the three neuroimaging parameters and the neurocognitive/symptom scores were below the threshold of a “small” effect size (r<0.10). The remaining (49.2%) correlations fell somewhere between “small” and “medium” effect sizes (0.1< r<0.3). However, all correlations were statistically non-significant.

Conclusions

The current results demonstrate minimal and statistically non-significant correlations among neuroimaging, neurocognitive, and symptom scores examined in a cohort of NFL retirees. While an often-accepted paradigm, certain neuroimaging findings may not relate consistently and directly with neurocognitive test performance and clinical symptom burden.

Competing interests

None.

GS Solomon receives consulting fees from the Tennessee Titans (NFL), the Nashville Predators (NHL), and the athletic departments of several universities; all fees paid to institution. In addition he is a member of the ImPACT Scientific Advisory Board and receives reimbursement for expenses to board meetings

AK Sills is a consulting physician to the Nashville Predators (uncompensated) and also serves as an unaffiliated neurotrauma consultant for the NFL

Examinations of the NFL retirees were sponsored by the National Football League (NFL) and coordinated with the NFL Players Association (NFLPA). IR Casson served as a member of the NFL MTBI Committee from 1994-2009 and as a co-chair from 2007-2009. He has done consulting for law firms and insurance companies.
Higher head accelerations observed in female athletes than in male athletes across age
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 compare linear and rotational acceleration across age and gender in controlled purposeful soccer heading.

Design

Prospective study.

Setting

Biomechanics laboratory.

Participants

One-hundred soccer players (42 male, 58 female, 17.1±3.5 years, 168.5±20.3 cm, 61.5±13.7 kg) classified as collegiate, high school (HS), or youth (12–14 years) male (MS) or female (FS) soccer players.

Exclusionary criteria

history of neurologic disorder, cervical spine injury, or head injury in the past 6 months.

Interventions

We implemented a unique soccer heading paradigm that allows for precise control of head impact magnitude, direction, and frequency to model repetitive head impacts in sport. This model consists of controlled soccer heading (12 headers at 11.2 m/s from a JUGS machine) while measuring linear and rotational accelerations using a triaxial accelerometer and gyroscope affixed to the back of the head. Linear accelerations were transformed to the head center-of-gravity using 3D motion capture data and standard rigid body dynamics equations.

Outcome measures

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

Main results

[Average±Standard Deviation (95% Confidence Interval)] Collegiate [42.4±11.5 g (36.8–47.9); 3.35±0.87 krad/s2(2.9–3.8)], HS [38.5±13.1 g (32.2–44.8); 3.16±1.01 krad/s2(2.7–3.7)], and youth [40.5±14.9 g(33.1–47.9); 3.20±1.24 krad/s2(2.6–3.8)] FS produced higher linear and rotational accelerations than both the collegiate [26.1±9.5 g(21.7–30.6); 2.13±1.07 krad/s2(1.6–2.6)] (linear: p<0.001, p?= 0.012, p=0.002; rotational: p=0.002, p=0.015, p=0.011, respectively) and HS [26.7±5.9 g(23.2–30.1); 2.18±0.40 krad/s2(2.0–2.4)] (linear: p=0.002, p=0.045, p?= 0.012; rotational: p=0.011, p=0.052, p=0.040, respectively) MS.

Conclusions

Collegiate and HS FS have higher head accelerations than their male counterparts, but at the youth level, there are no differences across gender. These data suggest that FS may be exposed to greater cumulative head accelerations from repeated heading of a soccer ball over a career than MS.

Competing interests

None.
Neurovascular coupling response is maintained despite exposure to repetitive sub-concussive head trauma over the course of one contact-sport season
Authors: Smirl Jonathan D , Wright Alexander D , Bouilane Kevin , Bryk Kelsey , Jakovac Michael , Donkelaar Paul van
Published: November 2017

Objective

To examine how head-impact exposures affect the elevation in cerebral blood velocity (CBV) in the posterior cerebral artery (PCA) during visual tasks.

Design

Prospective Cohort.

Setting

Laboratory.

Participants

To date: 40 male contact-sport athletes (19.4±1.2 years) and 3 cross-country athletes (20.0±1.0 years) have completed testing (non-contact controls).

Intervention

Transcranial Doppler ultrasound indexed PCA CBV during visual tasks. Participants closed their eyes (20-seconds), and when prompted, opened them and completed a visual task (40-seconds). Testing occurred prior-to and upon-completion-of the competitive athletic season. Raw traces from each trial were averaged to enhance the signal-to-noise ratio of outcome measurements. Independent variable tested was time (2).

Outcome

Eyes-closed CBV (cm/s), peak elevation in CBV (cm/s), relative change in CBV (%) and total activation during the first 30 seconds of the task (indexed via area under the curve-AUC). Head-impact exposure was characterised in a subset of contact-sport athletes (n=29) using the xPatch (X2 Biosystems).

Main results

RM-ANOVA indicated the contact-sport season had no effects on any outcome metrics: Eyes-closed CBV (p=0.181), peak CBV (p=0.117),% CBV elevation (p=0.252) and AUC (p=0.366), despite experiencing cumulative peak linear accelerations of 8147.2±6215.5g, and cumulative peak rotational accelerations of 34.5×106± 59.0×106rad/?s2.

Conclusions

The results from this study suggest neurovascular coupling metrics are maintained throughout a contact-sport season. This indicates nutrient delivery is maintained for neurocognitive challenges despite possible impairments in cerebrovasculature’s ability to buffer blood pressure challenges associated elevations in rotational accelerations experienced during a contact-sport season.

Competing interests

None.
Outcomes after sport-related concussion: does socioeconomic status matter?
Authors: Zuckerman Scott L , Kuhn Andrew W , Yengo-Kahn Aaron M , Zalneraitis Brian Holt , Solomon Gary S , Sills Allen K
Published: November 2017

Objective

To determine the impact of socioeconomic status (SES) on outcomes after sport-related concussion (SRC) in a regional sports concussion centre.

Design

Retrospective cohort study.

Setting

Comprehensive sports concussion centre.

Participants

282 youth, high school, and collegiate student-athletes.

Intervention

All patients seen at a comprehensive sports concussion centre were contacted after their injury for in-depth telephone interviews. Subsequent demographic data was also collected.

Outcome measures

SES was defined based on six variables: cost of living percentile, median income percentile, % college graduates, % homeowners, county type, and insurance. Outcomes after SRC were defined as the following three variables: days of symptom duration, days of missed school, and days of missed practice.

Main results

A total of 282 student-athletes were studied. The median age was 15.8 years (range 11.6–22.2). American football was the most common sport (32.2%). After multivariate cox-regression analysis, no relationship between SES and symptom duration or missed practice was seen. For the outcome of missed school, insurance status had a significant relationship, where those with private insurance had fewer missed days of school than those with public insurance (HR 0.46, 95% CI: 0.26–0.83, p=0.009).

Conclusions

In a regional cohort of youth, high school and collegiate student-athletes, SES had largely no impact on the outcomes of symptom duration, missed school, and missed practice. The only significant relationship was that those with private insurance returned to school quicker than those with public insurance, which may represent increased access to rehabilitation resources after SRC.

Competing interests

None.

GS Solomon receives consulting fees from the Tennessee Titans (NFL), the Nashville Predators (NHL), and the athletic departments of several universities, all fees paid to institution. In addition he is a member of the ImPACT Scientific Advisory Board and receives reimbursement for expenses to board meetings.

AK Sills is a consulting physician to the Nashville Predators (uncompensated) and also serves as an unaffiliated neurotrauma consultant for the NFL.
The prevalence of concussion within the military academies: findings from the concussion assessment, research, and education (care) consortium
Authors: O’Connor Kathryn L , Dain Allred C , Cameron Kenneth L , Campbell Darren E , Houston Megan N , Johnson Brian R , D’Lauro Chris , McGinty Gerald , O’Donnell Patrick G , Peck Karen Y , Svoboda Steven J , McCrea Michael , McAllister Thomas , Broglio Steven P
Published: November 2017

Objective

Describe prevalence and risk factors for concussion among USA Service Academy cadets.

Design

Prospective.

Setting

Three USA Service Academies.

Participants

NCAA and non-NCAA athlete cadets (n=7636, 22% female) enrolled in the CARE Consortium (2014–2015).

Assessment of risk factors

NCAA status, contact-sport, gender, and brief sensation seeking scale (BSSS) were examined as risk factors for previous concussion.

Outcome measures

Number of previous concussions.

Main results

21% of cadets reported a previous concussion with median time from injury being 2.5 years (IQR 0.99–4.57). At least one previous concussion occurred in 18% of freshman prior to Service Academy enrollment and 12% of sophomore through senior cadets sustained a concussion during their time at the academy. Cadets who are NCAA athletes had a 1.57 (95% CI: 1.12–2.19) greater odds of sustaining a concussion at the academy than non-NCAA cadets. Poisson regression modelling the number of previous concussions revealed significant main effects for contact-sport and BSSS. Controlling for BSSS, contact-sport cadets had 1.82 (95% CI: 1.69–1.95) times the prevalence rate of previous concussion compared to non-contact sport athletes. Additionally, controlling for contact-sport, higher BSSS scores increased prevalence of previous concussions by 1.17 (95% CI: 1.10–1.24) times.

Conclusions

Overall concussion prevalence among all service academy cadets is similar to prevalence of concussion previously reported for NCAA athletes. Within the academies, cadets who are also NCAA athletes have greater odds of concussion, likely due to increased risk exposure. Contact-sport status and increased sensation seeking is associated with increased number of previous concussions.

Competing Interests/ Acknowledgements

This project was supported, in part, with support from the Grand Alliance Concussion Assessment, Research, and Education (CARE) Consortium, funded, in part by the National Collegiate Athletic Association (NCAA) and the Department of Defense (DOD).

The U.S. Army Medical Research Acquisition Activity, 820 Chandler Street, Ford Detrick MD 21702–5014 is the awarding and administering acquisition office.

This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program under Award NO W81XWH-14-2-0151. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense (DHP funds.)
Eye movement and white matter integrity in patients with post-concussion syndrome
Authors: Taghdiri Foad , Irwin Samantha , Multani Namita , Tarazi Apameh , Ebraheem Ahmed , Chung Jonathan , Khodadadi Mozghan , Goswami Ruma , Wennberg Richard , Green Robin , Mikulis Dave , Tator Charles , Eizenman Moshe , Tartaglia Maria Carmela
Published: November 2017

Objective

To assess eye movements in patients with post-concussion syndrome (PCS) and use diffusion tensor imaging (DTI) to determine relationship between eye movements and white matter integrity.

Design

cross-sectional study.

Intervention

Attention and executive function were tested using Visual Attention Scanning Technology (VAST) [EL-MAR Inc., Toronto, Ontario, Canada]. In a matching task, the normalised number of transitions (NNT) to a master image before making the first selection was used as a surrogate of working memory. During this task, subjects view a set of slides, each slide includes a master image and six variants, and they have to select a variant that is similar to the master (only one variant is an exact replica of the master).

Outcome measures

We related performance on VAST to white matter integrity using Tract-Based Spatial Statistics of DTI metrics such as fractional anisotropy (FA) for whole brain analyses as well as seed-based probabilistic tractography analysis of the superior longitudinal fasciculus (SLF), Cingulum tract, and Uncinate fasciculus (UF).

Main results

60 participants (mean age 34.3 years, SD 13.8) had a mean of 4 concussions. There were negative correlations between whole brain FA and NNT (r=−0.501, p<0.001). In addition, when we performed probabilistic tractography analyses, we found a negative correlation between the FA of right SLF and NNT (r=−0.332, p=0.009).

Conclusions

Impaired performance on eye tracking measures of attention and executive function may reflect alterations in white matter tracts.

Competing interests

None.

Moshe Eizenman is a director in EL-MAR Inc.