Assoc Prof Andrew Gardner

Objectives: To provide normative reference values for the Sport Concussion Assessment Tool ¿ 5th Edition for elite-level male rugby league players. Design: A descriptive cross-sectional study. Methods: Baseline Sport Concussion Assessment Tool ¿ 5th Edition scores were obtained from 1005 National Rugby League players during the 2018 and 2019 preseasons. Normative values were calculated for the Standardized Assessment of Concussion, Symptom Evaluation (i.e., severity and number), and the Modified Balance Error Scoring System for each group and in total. Players self-identified their cultural heritage or ethnicity to be 'Pasifika (Pacific Islander) or Maori' (n = 243; 24.2 %) or 'Indigenous Australian' (n = 82; 8.2 %). Those who identified as any other race, ethnicity, or cultural heritage were combined into a single group (n = 680; 67.7 %). Results: In total the median Standardized Assessment of Concussion score was 27 (interquartile range = 25¿28), the median symptom severity was 0 (interquartile range = 0¿2), the median symptom number was 0 (interquartile range = 0¿1), and the median the Modified Balance Error Scoring System error score was 3 (interquartile range = 1¿5). Reporting 4 of 22 symptoms and 6 of 132 on the total severity score was uncommon. There was no significant difference between the cultural heritage or ethnicity groups for Standardized Assessment of Concussion scores, symptom severity or number, or Modified Balance Error Scoring System errors (p-values > 0.05). Conclusions: This normative data will assist with the clinical interpretation of Sport Concussion Assessment Tool ¿ 5th Edition scores following a concussion in the National Rugby League.

Objectives: Identify tackle characteristics associated with concussions in male professional rugby league. Design: Case-control study. Methods: Tackles resulting in 196 clinically diagnosed concussions and 6592 non-concussive tackles were analysed, from the men's rugby league Super League between 2018 and 2022. Eleven tackle characteristics were coded for each tackle, and Firth penalised logistic regression models were employed to identify influential variables through forward stepwise selection. Three multivariate models were produced; all (i.e., ball-carrier and tackler), tackler, and ball-carrier concussions. Results: Of the 196 concussions, 70 % occurred to the tackler and 30 % to the ball-carrier. Initial impact location on the ball-carrier was identified as a predictor in all models, specifically the shorts, upper- and lower-leg (OR 9.1¿12.3, compared to shoulder) for tacklers and head/neck (OR 66.1, compared to shoulder) for ball-carriers. Tackler head placement in front of the ball-carrier (OR 8.5, compared to away from the body) and a ball-carrier leading arm in any position (OR 4.8¿22.1, compared to no leading arm) provided the greatest odds of a tackler concussion. For player's body position the greatest risk of concussion for all players was observed when both players were falling/diving (OR 8.8, compared to both players upright). One (OR 4.9, compared to two) and four (OR 3.7, compared to two) defender tackles provide the greatest odds for all concussions. Conclusions: Concussion prevention strategies should aim to reduce head impacts by deterring initial contact with the ball-carrier's head/neck. Tackle technique should prioritise making initial impact with the torso and avoid the head being in front of the ball-carrier and any leading arms.

Objectives: This study investigated the disclosure and reasons for non-disclosure of possible concussions and their symptoms in National Rugby League Women's (NRLW) Premiership players in Australia. Design: Cross sectional survey. Methods: During the 2022 NRLW season, NRLW players were invited to participate in a voluntary, anonymous, online survey exploring (i) player demographics, (ii) rugby playing history, (iii) concussion disclosure, and (iv) instances of, and reasons for, non-disclosure of possible concussions to medical staff during the past two seasons. Logistic regression analyses were used to identify reasons for non-disclosure of possible concussions in NRLW players. Results: Of the 132 eligible participants, 86 players responded to the survey and 63 % (n = 54/86) reported that they always disclosed a possible concussion during the past two seasons. A substantial number of NRLW players surveyed (n = 32/86, 37 %) did not disclose a possible concussion to their team or medical staff on one or more occasions. Sixty-three players (73 %) always reported symptoms during a medical assessment. Twenty-three players (27 %) did not disclose their symptoms during a medical assessment, primarily during or after a game or training session (n = 12/23, 52 %). Of the players who did not disclose their possible concussion symptoms, the two main reasons for non-disclosure were 'not wanting to be ruled out of the game or training session' (n = 8/23,35 %) and not being 'sure if the symptoms were related to concussion' (n = 8/23, 35 %). Most surveyed players (n = 74/86, 86 %) reported attending mandatory concussion education sessions at their respective clubs. Conclusion: We found high rates of non-disclosure amongst NRLW players, which is inconsistent with previous research suggesting that women are more aware of their symptoms than men and more likely to disclose their concussions. Not wanting to be ruled out of the game or training session and being unsure if the symptoms were related to concussion were the two most common reasons for nondisclosure. Concussion education initiatives could promote a supportive culture fostering disclosure amongst all stakeholders to ensure optimal player welfare.

Purpose: Head acceleration events (HAEs) are a growing concern in contact sports, prompting two rugby governing bodies to mandate instrumented mouthguards (iMGs). This has resulted in an influx of data imposing financial and time constraints. This study presents two computational methods that leverage a dataset of video-coded match events: cross-correlation synchronisation aligns iMG data to a video recording, by providing playback timestamps for each HAE, enabling analysts to locate them in video footage; and post-synchronisation event matching identifies the coded match event (e.g. tackles and ball carries) from a video analysis dataset for each HAE, this process is important for calculating the probability of match events resulting in HAEs. Given the professional context of iMGs in rugby, utilising commercial sources of coded match event datasets may expedite iMG analysis. Methods: Accuracy and validity of the methods were assessed via video verification during 60 rugby matches. The accuracy of cross-correlation synchronisation was determined by calculating synchronisation error, whilst the validity of post-synchronisation event matching was evaluated using diagnostic accuracy measures (e.g. positive predictive value [PPV] and sensitivity). Results: Cross-correlation synchronisation yielded mean synchronisation errors of 0.61¿0.71¿s, with all matches synchronised within 3¿s' error. Post-synchronisation event matching achieved PPVs of 0.90¿0.95 and sensitivity of 0.99¿1.00 for identifying correct match events for SAEs. Conclusion: Both methods achieved high accuracy and validity with the data sources used in this study. Implementation depends on the availability of a dataset of video-coded match events; however, integrating commercially available video-coded datasets offers the potential to expedite iMG analysis, improve feedback timeliness, and augment research analysis.

Objectives: To evaluate if the tackler correctly adhering, or not, to four different instructions of legal front-on one-on-one torso tackles altered the tackler and/or ball carrier peak inertial head kinematics. Design: Controlled laboratory study. Methods: Fifteen rugby-code players measured with three-dimensional optoelectronic motion capture performed two tackle instructions from the Australian National Rugby League coaching manual on under (Dominant National Rugby League) and over (Smother National Rugby League) the ball tackles, and two novel variants of these (under, Dominant, Torso Stick; over, Smother, Pop, Lock). A series of mixed general linear models identified if the tackler adhering (n = 455), or not (n = 139) to the tackle instructions altered peak inertial head kinematics. Results: The tackler's peak inertial head kinematics did not significantly change whether or not they adhered to each of the tackle instructions. When the tackler did adhere to the instructions, the ball carrier sustained a lower peak inertial head kinematics (p < 0.01) in the Smother National Rugby League tackle but higher peak inertial head kinematics in the Smother, Pop, Lock. Conclusions: The ball carriers' inertial head kinematics but not the tacklers were increased when the tackler adhered to this study's variants of the over and under the ball tackle instructions, suggesting that the tacklers were more effective in their tackle performance than the traditional tackle instructions when adhering to the tackle instruction. Greater adherence to the under the ball instructions suggests that the over the ball instruction is a more challenging technique to learn.

Background: The risk of concussion at the elite level of rugby league has been extensively evaluated. However, there has been very little concussion research conducted at the semi-elite level. Purpose: To examine cases of medically diagnosed concussion from a single season of adult men's semi-elite rugby league. Methods: A retrospective review of the 2019 Queensland Cup season head injury assessment surveillance program was completed. All Head Injury Assessment (HIA) cases, including cases of medically diagnosed concussion were retrospectively video reviewed and game play characteristic variables along with video signs of concussion were coded. This data was combined with the return to play data to form the research database. Results: There were 132 players removed for HIAs in 170 games. There were 36 players medically diagnosed with concussions, which equates to an incidence rate was 6.11 concussions per 1000 player match hours, or one concussion every 4.7 matches. All concussions occurred in a tackle event, where the player was struck in the head/face. Possible balance disturbance was the most commonly observed video sign (97.2 ¿%; 35/36), with slow to stand also commonly observed in concussed players (91.7 ¿%; 33/36). Most concussed players (63.9 ¿%; 23/36) did not miss a game following the concussion. Conclusion: This is one of the first studies to review video footage of concussions in sub-elite rugby league. These findings build on the growing body of video analysis research in rugby league and suggest that the retrospective review of the video of incidents may offer insights into modifiable risk factors that may help reduce concussion in rugby league.

Head acceleration events (HAEs) are acceleration responses of the head following external short-duration collisions. The potential risk of brain injury from a single high-magnitude HAE or repeated occurrences makes them a significant concern in sport. Instrumented mouthguards (iMGs) can approximate HAEs. The distinction between sensor acceleration events, the iMG datum for approximating HAEs and HAEs themselves, which have been defined as the in vivo event, is made to highlight limitations of approximating HAEs using iMGs. This article explores the technical limitations of iMGs that constrain the approximation of HAEs and discusses important conceptual considerations for stakeholders interpreting iMG data. The approximation of HAEs by sensor acceleration events is constrained by false positives and false negatives. False positives occur when a sensor acceleration event is recorded despite no (in vivo) HAE occurring, while false negatives occur when a sensor acceleration event is not recorded after an (in vivo) HAE has occurred. Various mechanisms contribute to false positives and false negatives. Video verification and post-processing algorithms offer effective means for eradicating most false positives, but mitigation for false negatives is less comprehensive. Consequently, current iMG research is likely to underestimate HAE exposures, especially at lower magnitudes. Future research should aim to mitigate false negatives, while current iMG datasets should be interpreted with consideration for false negatives when inferring athlete HAE exposure.

Introduction: Some ultra-high exposure boxers from the 20th century suffered from neurological problems characterized by slurred speech, personality changes (e.g., childishness or aggressiveness), and frank gait and coordination problems, with some noted to have progressive Parkinsonian-like signs. Varying degrees of cognitive impairment were also described, with some experiencing moderate to severe dementia. The onset of the neurological problems often began while they were young men and still actively fighting. More recently, traumatic encephalopathy syndrome (TES) has been proposed to be present in athletes who have a history of contact (e.g., soccer) and collision sport participation (e.g., American-style football). The characterization of TES has incorporated a much broader description than the neurological problems described in boxers from the 20th century. Some have considered TES to include depression, suicidality, anxiety, and substance abuse. Purpose: We carefully re-examined the published clinical literature of boxing cases from the 20th century to determine whether there is evidence to support conceptualizing psychiatric problems as being diagnostic clinical features of TES. Methods: We reviewed clinical descriptions from 155 current and former boxers described in 21 articles published between 1928 and 1999. Results: More than one third of cases (34.8%) had a psychiatric, neuropsychiatric, or neurobehavioral problem described in their case histories. However, only 6.5% of the cases were described as primarily psychiatric or neuropsychiatric in nature. The percentages documented as having specific psychiatric problems were as follows: depression = 11.0%, suicidality = 0.6%, anxiety = 3.9%, anger control problems = 20.0%, paranoia/suspiciousness = 11.6%, and personality change = 25.2%. Discussion: We conclude that depression, suicidality (i.e., suicidal ideation, intent, or planning), and anxiety were not considered to be clinical features of TES during the 20th century. The present review supports the decision of the consensus group to remove mood and anxiety disorders, and suicidality, from the new 2021 consensus core diagnostic criteria for TES. More research is needed to determine if anger dyscontrol is a core feature of TES with a clear clinicopathological association. The present findings, combined with a recently published large clinicopathological association study, suggest that mood and anxiety disorders are not characteristic of TES and they are not associated with chronic traumatic encephalopathy neuropathologic change.

Objective: The tackle is the most injurious event in rugby league and carries the greatest risk of concussion. This study aims to replicate previous research conducted in professional men's rugby league by examining the association between selected tackle characteristics and head impact events (HIEs) in women's professional rugby league. Methods: We reviewed and coded 83 tackles resulting in an HIE and every tackle (6,318 tackles) that did not result in an HIE for three seasons (2018¿2020) of the National Rugby League Women's (NRLW) competition. Tackle height, body position of the tackler and ball carrier, as well as the location of head contact with the other player's body were evaluated. Propensity of each situation that caused an HIE was calculated as HIEs per 1,000 tackles. Results: The propensity for tacklers to sustain an HIE was 6.60 per 1,000 tackles (95% CI: 4.87¿8.92), similar to that of the ball carrier (6.13 per 1,000 tackles, 95% CI: 4.48¿8.38). The greatest risk of an HIE to either the tackler or ball carrier occurred when head proximity was above the sternum (21.66 per 1,000 tackles, 95% CI: 16.55¿28.35). HIEs were most common following impacts between two heads (287.23 HIEs per 1,000 tackles, 95% CI: 196.98¿418.84). The lowest propensity for both tackler (2.65 per 1,000 tackles, 95% CI: 0.85¿8.20) and ball carrier HIEs (1.77 per 1,000 tackles, 95% CI: 0.44¿7.06) occurred when the head was in proximity to the opponent's shoulder and arm. No body position (upright, bent or unbalanced/off feet) was associated with an increased propensity of HIE to either tackler or ball carrier. Conclusions: In the NRLW competition, tacklers and ball carriers have a similar risk of sustaining an HIE during a tackle, differing from men's NRL players, where tacklers have a higher risk of HIEs. Further studies involving larger samples need to validate these findings. However, our results indicate that injury prevention initiatives in women's rugby league should focus on how the ball carrier engages in contact during the tackle as well as how the tackler executes the tackle.

Objectives: To quantify the incidence of concussion and compare between playing levels in male rugby league. Design: Retrospective cohort. Methods: Between 2016 and 2022, medically diagnosed concussions in Super League, Championship, and Academy competitions were reported to the Rugby Football League via club medical staff. Anonymised data were analysed using generalised linear mixed-effects models by season, month, and between competitions. Results: Overall, 1403 concussions were identified from 104,209 player-match hours. Concussion incidence for Super League, Championship, and Academy was 15.5, 10.5, and 14.3 per 1000 player-match hours, respectively. Championship concussion incidence was significantly lower than the Super League (p < 0.001) and Academy (p < 0.001). No significant differences were identified between years for Super League (range: 13.3 to 18.8 per 1000 player-match hours) and Championship (range: 8.4 to 12.1 per 1000 player-match hours). In Academy (range: 9.6 to 20.5 per 1000 player-match hours), concussion incidence was significantly greater in 2021 compared to earlier years (2016, p = 0.01 and 2017, p = 0.03). No significant differences were identified between months for any competition. Conclusions: The incidence of concussion is greater in Super League and Academy compared to the Championship. Academy concussion incidence has increased over time. Different factors between and within competitions, such as changes to medical standards and knowledge, could have influenced the identification and diagnosis of concussion.

Background: Individuals with migraine disorders may be affected differently by concussions compared to individuals without migraine disorders. Prior studies on this topic have had mixed results. The purpose of this study was to systematically examine clinical outcomes following a sport-related concussion in athletes who have a pre-injury history of migraines. Methods: All studies published prior to 15 May 2021 that examined pre-injury migraines as a possible predictor of clinical recovery from concussion were included. The search included (i) sport/athlete-related terms, (ii) concussion-related terms, and (iii) diverse predictor/modifier terms. After removing duplicates, 5,118 abstracts were screened, 538 full-text articles were reviewed, and 27 articles were included for narrative synthesis without meta-analysis (n = 25 with unique samples). Risk of bias was assessed using the domain-based Quality In Prognosis Studies (QUIPS) tool. Results: Most studies did not find pre-injury migraines to be associated with concussion outcome, but several of these studies had small or very small sample sizes, as well as other methodological weaknesses. Risk of bias varied greatly across studies. Some of the larger, better-designed studies suggested pre-injury migraines may be a risk factor for worse concussion outcome. Most articles examined pre-injury migraines as an exploratory/secondary predictor of concussion outcome; very few were designed to examine migraine as the primary focus of the study. Migraine history was predominantly based on self-report and studies included minimal information about migraine (e.g., age of onset, frequency/severity, past treatment). Effect sizes were usually not reported or able to be calculated from reported study data. Conclusion: There is some evidence to suggest that pre-injury migraines may be a vulnerability factor for a worse outcome following concussion, with studies having the lowest risk of bias reporting a positive association. Future studies should focus on improving methodological quality when assessing the relationship between pre-injury migraines and concussion outcome and better characterizing pre-injury migraine status. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019128292, identifier: PROSPERO 2019 CRD42019128292.

Background: Higher neck strength has been postulated to reduce head impact magnitude during purposeful heading in football. Objectives: This pilot trial explored the effect of a neck exercise programme on (1) neck strength and (2) head impact magnitude during heading in male and female adolescent football players. Methods: Boys and girls (aged 12¿17¿years) were randomised by team to the intervention (5¿weeks of supervised neuromuscular neck exercises integrated into part 2 of the FIFA 11 + , completed three times per week) or the control group (usual part 2 of the FIFA 11 + , no neck exercises). Outcomes included isometric neck strength and head impact magnitude (peak linear acceleration and peak angular velocity) during standardised heading from a throw-in (at baseline and 6¿weeks) plus completion of an evaluation survey by intervention players and coaches. Results: In total, 52 players (n = 31 intervention; n = 21 control) completed the study. Mixed-model analysis of variance (ANOVA) revealed significant differences in neck strength variables (p < 0.001), peak linear acceleration (p = 0.04) and peak angular velocity (p = 0.04) between the intervention and control groups over time. Intervention players demonstrated increases in mean composite neck strength (53.8% intervention vs 15.6% control) as well as decreases in mean peak linear head acceleration during heading (- 11.8% vs - 5.0%) from baseline to follow-up. Reduction in peak angular velocity was more pronounced in girls (- 27.7%) than boys (- 11.5%) in the intervention group. The addition of neck exercises into part 2 of the FIFA 11 + was feasible and accepted by players and coaches. Conclusion: On average, players who completed neck exercises demonstrated an increase in isometric neck strength and a decrease in head impact magnitude during heading. These exercises were easily incorporated into usual training. Australian New Zealand Clinical Trials Registry (no: ACTRN12619001375145).

Objective: To examine the relationship between video-identified onfield motor incoordination, the acute assessment of concussion, and recovery time during three seasons of National Rugby League (NRL) play. Methods: Blows to the head ("head impact events") were recorded by sideline video operators and medical staff. Any player with a suspected concussion underwent a Head Injury Assessment in which he was taken off the field and medically evaluated, including the administration of the Sports Concussion Assessment Tool, 5th Edition (SCAT5). Video footage was later examined to determine the presence or absence of onfield motor incoordination following the head impact event. Results: Motor incoordination was identified in 100/1,706 head impact events (5.9%); 65 of the 100 instances of motor incoordination (65.0%) were ultimately medically diagnosed with a concussion. In 646 athletes for whom SCAT5 data were available, those with motor incoordination were more likely to report both dizziness and balance problems than those without motor incoordination, but there were no group differences on an objective balance test. Additionally, there was no relationship between presence/absence of motor incoordination and number of games missed or time to medical clearance for match play. Conclusion: In NRL players, motor incoordination is a readily observable onfield sign that is strongly associated with a medical diagnosis of concussion and with self-reported dizziness/balance problems. However, onfield motor incoordination is not associated with objective balance performance and it is not predictive of time to recover following concussion.

BACKGROUND: Consensus on the definition of extant video signs of concussion have recently been proposed by representatives of international sporting codes for global consistency across professional leagues. OBJECTIVE: To review the reliability of the proposed international consensus video signs of concussion in National Rugby League (NRL) head impact events (HIEs). METHODS: The video signs of concussion were coded for every HIE during the 2019 NRL season. Coding was conducted blinded to the concussion status. Frequency, sensitivity, specificity, and a receiver operating characteristic curve were calculated. RESULTS: There were 943 HIEs identified over the 2019 NRL season, of which 106 resulted in a diagnosed concussion. The most frequently observed video sign in concussed athletes was blank/vacant look (54%), which was also the most sensitive video sign (0.54, CI: 0.44-0.63), while the most specific was tonic posturing (0.99, CI: 0.99-1.00). In 43.4% of diagnosed concussions none of the 6 video signs were present. The 6 video signs demonstrated a "fair"ability to discriminate between concussion and nonconcussion HIEs (area under the curve = 0.76). CONCLUSION: International consensus agreement between collision sports for extant video signs of concussion and the definition of those extant video signs are clinically important. The selection of signs requires rigorous assessment to examine their predictive value across all sports and within individual sports, and to determine further video signs to compliment and improve the identification of possible concussion events within various sports. The current study demonstrated that, for NRL-related HIEs, the diagnostic accuracy of video signs varies.

The tackle is the in-game activity with the greatest risk for injury in collision sports. Qualitative match analysis has associated injury risk with tackle technique (e.g. tackle height, head position before contact). This exploratory study used gold-standard three-dimensional (3D) motion capture to investigate whether prior instructions to a tackler to execute different torso tackle types altered their tackle technique. Fifteen amateur-level rugby code players performed four sets of 10 tackle trials after instructions from an expert coach: two Australian National Rugby League (NRL) coaching manual instructions on upper and lower torso tackle height (UpperNRL, LowerNRL); and two novel variants that altered the tackler's contact with the ball carrier's upper torso (UpperPop) via a vertical 'pop action', or mid-torso (MidTorso) via increasing the contact height to the mid-torso. 3 D motion capture confirmed a favourable 'head up and forward' gaze focus on ball carrier before contact and a 'straight back' posture was more evident in UpperPop instruction than other instructions, with the least flexion for the head, trunk, trunk-pelvis, thoracolumbar and lumbopelvic (p < 0.01). MidTorso also attained a more optimal 'head up and forward' and a 'straight back' posture than a LowerNRL (p < 0.001). 'Leg drive on contact' revealed ankle, hip (p < 0.01) and thigh angles (p < 0.05) differences, likely to reflect the UpperPop 'pop action' instruction than other instructions. For coaches, this study demonstrated that amateur-level rugby-code players could follow instruction from an expert coach to execute tackling techniques within a session. Inclusion of tackle specific coaching instruction training program may be a viable injury reduction strategy.

Background: Exposure to thousands of head and body impacts during a career in contact and collision sports may contribute to current or later life issues related to brain health. Wearable technology enables the measurement of impact exposure. The validation of impact detection is required for accurate exposure monitoring. In this study, we present a method of automatic identification (classification) of head and body impacts using an instrumented mouthguard, video-verified impacts, and machine-learning algorithms. Methods: Time series data were collected via the Nexus A9 mouthguard from 60 elite level men (mean age = 26.33; SD = 3.79) and four women (mean age = 25.50; SD = 5.91) from the Australian Rules Football players from eight clubs, participating in 119 games during the 2020 season. Ground truth data labeling on the captures used in this machine learning study was performed through the analysis of game footage by two expert video reviewers using SportCode and Catapult Vision. The visual labeling process occurred independently of the mouthguard time series data. True positive captures (captures where the reviewer directly observed contact between the mouthguard wearer and another player, the ball, or the ground) were defined as hits. Spectral and convolutional kernel based features were extracted from time series data. Performances of untuned classification algorithms from scikit-learn in addition to XGBoost were assessed to select the best performing baseline method for tuning. Results: Based on performance, XGBoost was selected as the classifier algorithm for tuning. A total of 13,712 video verified captures were collected and used to train and validate the classifier. True positive detection ranged from 94.67% in the Test set to 100% in the hold out set. True negatives ranged from 95.65 to 96.83% in the test and rest sets, respectively. Discussion and conclusion: This study suggests the potential for high performing impact classification models to be used for Australian Rules Football and highlights the importance of frequencies <150 Hz for the identification of these impacts.

Rugby league has been identified as a contact sport with a high incidence of concussion. Research has been conducted to describe incidence and mechanisms of concussion in rugby league, however the risks associated with injury events (shoulder, hip, head to head) are unknown. The purpose of this study was to describe the common injury events leading to concussion in the National Rugby League and compare these events through analysis of dynamic response and brain tissue deformation. Twenty-seven impact videos of concussive injuries were physically reconstructed to obtain linear and rotational accelerations of the head. Dynamic response data were input into the University College Dublin Brain Trauma Model (UCDBTM) to calculate maximum principal strain (MPS). Head-to-head events produced a short duration event with an average peak linear and peak rotational acceleration of 205g and 15,890 rad/s2, respectively, which were significantly greater than the longer duration hip-to-head (24.7g and 2650 rad/s2) and shoulder-to-head (24.2g and 3280 rad/s2) impacts. There were no differences in MPS between events. These results suggest that risk of strain to the brain may be produced by short and long duration acceleration events. Thus, both of these accelerations need to be accounted for in the development of improved head and body protection in rugby. In addition, this data demonstrates that these events cause a risk of concussion requiring efforts to limit or modify how energy is transferred to the head.

Objective: To establish normative reference values for the Sport Concussion Assessment Tool-5th Edition (SCAT5) for the new National Rugby League Women's Premiership. Methods: Preseason SCAT5 baseline testing was administered individually to all National Rugby League Women's Premiership players (N = 117). Testing was completed by the medical staff. Normative reference values were calculated for the components of the SCAT5, including the Standardized Assessment of Concussion, modified Balance Error Scoring System, and the Symptom Scale. A small case series of players who sustained concussions were included to illustrate the use of the new normative data. Results: The median Standardized Assessment of Concussion total score was 27.0 (M = 26.9, SD = 2.1). The median modified Balance Error Scoring System score was 2.0 (M = 2.4, SD = 2.2). The median number of symptoms score was 1.0 (M = 3.2, SD = 4.7) and the median symptom severity score was 2.0 (M = 5.4, SD = 8.2). The most common baseline symptom was fatigue or low energy (33%), followed by trouble sleeping (24%), headache (23%), neck pain (22%), and difficulty remembering (21%). In the total sample, 41% reported no symptoms. The clinical interpretation of these new normative data to a case series of women with concussions is provided. Conclusions: Normative reference values are provided for the SCAT5 for women who are professional rugby league players. Using these normative data will improve clinical interpretation of SCAT5 scores following a concussion.

Objective: To examine the effect of prior concussion history on cognitive test performance and concussion symptom reporting among adolescent youth rugby league athletes.Participants: Participants were male elite level youth rugby league players (N = 73; Mean Age = 15.8; SD = 0.9; range = 14¿18 years).Main Outcome Measure: CogSport performance based on participants group; those who reported no previous concussions (n = 30),1¿2 previous concussions (n = 19), and =3 previous concussions (n = 29).Results: 73 participants with valid CogSport scores were included in the cognitive analyses. All participants were included in the symptom analyses. There were no differences between the groups with 0,1¿2, or =3 previous concussions for processing speed, attention, learning, or working memory. There was atrend for those with multiple prior concussions to report more baseline preseason symptoms.Conclusions: There were no differences in scores on the CogSport test among those with ahistory of 0,1¿2, or =3 prior concussions. Consistent with prior studies, youth with ahistory of multiple past concussions are more likely to endorse baseline preseason symptoms.

Objective: In recent years, it has been proposed that depression represents one clinical subtype of chronic traumatic encephalopathy (CTE). This is the first study to examine the specificity of the research criteria for the clinical diagnosis of CTE in men with depression from the general population. Methods: Data from the National Comorbidity Survey Replication, an in-person survey that examined the prevalence and correlates of mental disorders in the United States, were used for this study. Men diagnosed as having a major depressive episode in the past 30 days were included (N=101; mean age=39.4 years, SD=12.9, range=18¿71). They were deemed to meet research criteriafor CTE if they presented with the purported supportive clinical features of CTE (e.g., impulsivity and substance abuse, anxiety, apathy, suicidality, and headache). Results: Approximately half of the sample (52.5%) met the proposed research criteria for CTE (i.e., traumatic enceph-alopathy syndrome). If one accepts the delayed-onset criterion as being present, meaning that the men in the sample were presenting with depression years after re-tirement from sports or the military, then 83.2% of this sample would meet the research criteria for diagnosis. Conclusions: The clinical problems attributed to CTE, such as depression, suicidality, anxiety, anger control problems, and headaches, co-occurred in this sample of men with depression from the general population¿illustrating that these problems are not specific or unique to CTE. More research is needed to determine whether depression is, in fact, a clinical subtype of CTE.

Objectives: To prospectively evaluate single/dual-task timed-up-and-go (TUG) and tandem gait performance among children and adolescents with concussion and healthy controls. Design: Repeated measures. Methods: Participants with concussion (n = 23; age = 14.1 ± 2.5 years; 52% female) completed single/dual-task TUG, tandem gait, and symptom assessments 6.7 ± 2.6 and 23.3 ± 6.1 days post injury. The control group (n = 27; age = 14.1 ± 2.3 years; 48% female) completed the same protocol initially and 10.7 ± 16.1 days later. All participants completed single-task (undivided attention) and dual-task (divided attention) tests. The primary outcome variable was test completion time. Results: The concussion group completed single-task (concussion group mean = 11.1 ± 1.9 vs. control group mean 9.9 ± 1.4 s, p = 0.027) and dual-task (concussion group mean = 14.4 ± 3.3 vs. control group mean 12.7 ± 1.9 s, p = 0.047) TUG tests slower than the control group across both time points. The concussion group completed dual-task tandem gait tests slower than the control group at both time points (21.3 ± 6.3 vs. 16.8 ± 5.5 s, p = 0.006), and were slower in the single-task condition at the first test (19.8 ± 5.4 vs. 13.8 ± 4.4 s, p = 0.003). Symptoms were significantly worse for the concussion group compared to the control group at the first (34.1 ± 21.4 vs. 3.9 ± 9.1, p < 0.001), but not the second test (9.1 ± 12.0 vs. 2.2 ± 6.8; p = 0.08). Conclusions: Slower dual-task TUG and tandem gait times were detected across both time points for the concussion group relative to the control group. In contrast, single-task tandem gait deficits appeared to improve in a similar fashion as symptoms, suggesting increased complexity from the addition of a cognitive task allows for the detection of persistent post-concussion deficits that might take longer to resolve.

In the 20th century, chronic traumatic encephalopathy (CTE) was conceptualized as a neurological disorder affecting some active and retired boxers who had tremendous exposure to neurotrauma. In recent years, the two research groups in the USA who have led the field have asserted definitively that CTE is a delayed-onset and progressive neurodegenerative disease, with symptoms appearing in midlife or decades after exposure. Between 2005 and 2012 autopsy cases of former boxers and American football players described neuropathology attributed to CTE that was broad and diverse. This pathology, resulting from multiple causes, was aggregated and referred to, in toto, as the pathology 'characteristic' of CTE. Preliminary consensus criteria for defining the neuropathology of CTE were forged in 2015 and published in 2016. Most of the macroscopic and microscopic neuropathological findings described as characteristic of CTE, in studies published before 2016, were not included in the new criteria for defining the pathology. In the past few years, there has been steadily emerging evidence that the neuropathology described as unique to CTE may not be unique. CTE pathology has been described in individuals with no known participation in collision or contact sports and no known exposure to repetitive neurotrauma. This pathology has been reported in individuals with substance abuse, temporal lobe epilepsy, amyotrophic lateral sclerosis, multiple system atrophy, and other neurodegenerative diseases. Moreover, throughout history, some clinical cases have been described as not being progressive, and there is now evidence that CTE neuropathology might not be progressive in some individuals. Considering the current state of knowledge, including the absence of a series of validated sensitive and specific biomarkers, CTE pathology might not be inexorably progressive or specific to those who have experienced repetitive neurotrauma.

U SYNOPSIS: Sport-related concussion is common in full-contact and collision sports. Epidemiology studies use different types of surveillance systems and concussion definitions. Concussion incidence rates vary across age, sex, sport, and level of competition. Incidence rates are increasing, likely due to higher rates of reporting following improved knowledge and increased regulations. In this review, we summarize 7 key concepts related to concussion epidemiology: concussion definition, changes in concussion knowledge, reliability and accuracy of injury surveillance systems, conservative management and return to play, reliability of self-report, incidence of concussion across levels of play, and understanding the behaviors of players, coaches, and medical personnel from a multidisciplinary management perspective.

Objective: In recent years, it has been proposed that problems with anger control and depression define clinical features of chronic traumatic encephalopathy (CTE). The authors examined anger problems and depression in middle-aged men from the general population and related those findings to the proposed clinical criteria for CTE. Methods: A sample of 166 community-dwelling men ages 40¿60 was extracted from the normative database of the National Institutes of Health Toolbox. All participants denied prior head injury or traumatic brain injury (TBI). Participants completed scales assessing anger, hostility, aggression, anxiety, and depression. Results: In response to the item "I felt angry," 21.1% of men reported "sometimes," and 4.8% reported "often." When asked "If I am provoked enough I may hit another person," 11.4% endorsed the statement as true. There were moderate correlations between anger and anxiety (Spearman's r=0.61) and between depression and affective anger (r=0.51), hostility (r=0.56), and perceived hostility (r=0.35). Participants were dichotomized into a possible depression group (N=49) and a no-depression group (N=117) on the basis of the question "I feel depressed," specific to the past 7 days. The possible depression group reported higher anxiety (p<0.001, Cohen's d=1.51), anger (p<0.001, Cohen's d=0.96), and hostility (p<0.001, Cohen's d=0.95). Conclusions: Some degree of anger and aggression are reported by a sizable minority of middle-aged men in the general population with no known history of TBI. Anger and hostility are correlated with depression and anxiety, indicating that all tend to co-occur. The base rates and comorbidity of affective dysregulation in men in the general population is important to consider when conceptualizing CTE phenotypes.

With the continued advancement in technology, such as increasingly sophisticated neuroimaging parameters, and the ongoing development of various scientific fields, like serum and blood biomarkers, genetics, and physiology, traumatic brain injury (TBI) research is a dynamic field of study. TBI remains a significant public health concern and research has continued to grow exponentially over the past decade. This review provides an overview of the frontiers of TBI research, from sports concussion to severe TBI, from acute and subacute injury to long-term/chronic outcomes, from assessment and management to prognosis, specifically examining recent neuroimaging, biomarkers, genetics, and physiologic studies.

Primary Objective: This study reviewed the available sideline Sport Concussion Assessment Tool-Third Edition (SCAT3) performance of players who were removed from play using the 'concussion interchange rule' (CIR), the available video footage of these incidences, and associated return to play and concussion diagnosis decisions. Research Design: Descriptive, observational case series. Methods and Procedures: Data were collected from all NRL players who used the CIR during the 2014 season. Main Outcomes and Results: Complete SCAT3 and video analysis data were available for 38 (23%) of 167 uses of the concussion interchange rule, of which 20 (52.6%) players were medically diagnosed with concussion. Those with video evidence of unresponsiveness performed more poorly on the modified Balance Error Scoring System (M-BESS; p¿=.04; Cohen's d¿=.69) and reported greater symptoms (p¿=.03; d¿=.51). Similarly, players with a vacant stare reported greater symptoms (p¿=.05; d¿=.78). Those who demonstrated three signs (unresponsiveness, vacant stare and gait ataxia) performed more poorly on the M-BESS (p¿=.03; d¿=¿1.4) and reported greater symptoms than those with no observable signs (p¿=.03; d¿=¿1.4). Conclusions: The SCAT3 is sensitive to the acute effects of concussion in professional athletes; however, a minority of injured athletes might go undetected by this test.

Objective Systematic review of possible long-term effects of sports-related concussion in retired athletes. Data sources Ten electronic databases. Study selection Original research; incidence, risk factors or causation related to long-term mental health or neurological problems; individuals who have suffered a concussion; retired athletes as the subjects and possible long-term sequelae defined as >10 years after the injury. Data extraction Study population, exposure/outcome measures, clinical data, neurological examination findings, cognitive assessment, neuroimaging findings and neuropathology results. Risk of bias and level of evidence were evaluated by two authors. Results Following review of 3819 studies, 47 met inclusion criteria. Some former athletes have depression and cognitive deficits later in life, and there is an association between these deficits and multiple prior concussions. Former athletes are not at increased risk for death by suicide (two studies). Former high school American football players do not appear to be at increased risk for later life neurodegenerative diseases (two studies). Some retired professional American football players may be at increased risk for diminishment in cognitive functioning or mild cognitive impairment (several studies), and neurodegenerative diseases (one study). Neuroimaging studies show modest evidence of macrostructural, microstructural, functional and neurochemical changes in some athletes. Conclusion Multiple concussions appear to be a risk factor for cognitive impairment and mental health problems in some individuals. More research is needed to better understand the prevalence of chronic traumatic encephalopathy and other neurological conditions and diseases, and the extent to which they are related to concussions and/or repetitive neurotrauma sustained in sports.

Background Sports concussion is a risk for players involved in high impact, collision sports. Post-concussion, the majority of symptoms subside within 7¿10 days, but can persist in 10¿20% of athletes. Understanding the effects of sports concussion on sensorimotor systems could inform physiotherapy treatment. Objective To explore changes in sensorimotor function in the acute phase following sports concussion. Design Prospective cohort study. Methods Fifty-four players from elite rugby union and league teams were assessed at the start of the playing season. Players who sustained a concussion were assessed three to five days later. Measures included assessments of balance (sway velocity), vestibular system function (vestibular ocular reflex gain; right-left asymmetry), cervical proprioception (joint position error) and trunk muscle size and function. Results During the playing season, 14 post-concussion assessments were performed within 3¿5 days of injury. Significantly decreased sway velocity and increased size/contraction of trunk muscles, were identified. Whilst not significant overall, large inter-individual variation of test results for cervical proprioception and the vestibular system was observed. Limitations The number of players who sustained a concussion was not large, but numbers were comparable with other studies in this field. There was missing baseline data for vestibular and cervical proprioception testing for some players. Conclusions Preliminary findings post-concussion suggest an altered balance strategy and trunk muscle control with splinting/over-holding requiring consideration as part of the development of appropriate physiotherapy management strategies.

Risk factors for concussion in active-duty military service members are poorly understood. The present study examined the association between self-reported concussion history and genetics (apolipoprotein E [APOE], brain-derived neurotrophic factor [BDNF], and D2 dopamine receptor genes [DRD2]), trait personality measures (impulsive-sensation seeking and trait aggression-hostility), and current alcohol use. The sample included 458 soldiers who were preparing to deploy for Operation Iraqi Freedom/Operation Enduring Freedom. For those with the BDNF Met/Met genotype, 57.9% (11/19) had a history of one or more prior concussions, compared with 35.6% (154/432) of those with other BDNF genotypes (p = 0.049, odds ratio [OR] = 2.48). APOE and DRD2 genotypes were not associated with risk for past concussions. Those with the BDNF Met/Met genotype also reported greater aggression and hostility personality characteristics. When combined in a predictive model, prior military deployments, being male, and having the BDNF Met/Met genotype were independently associated with increased lifetime history of concussions in active-duty soldiers. Replication in larger independent samples is necessary to have more confidence in both the positive and negative genetic associations reported in this study.

Chronic traumatic encephalopathy (CTE) has been described in the literature as a neurodegenerative disease with: (i) localized neuronal and glial accumulations of phosphorylated tau (p-tau) involving perivascular areas of the cerebral cortex, sulcal depths, and with a preference for neurons within superficial cortical laminae; (ii) multifocal axonal varicosities and axonal loss involving deep cortex and subcortical white matter; (iii) relative absence of beta-amyloid deposits; (iv) TDP-43 immunoreactive inclusions and neurites; and (v) broad and diverse clinical features. Some of the pathological findings reported in the literature may be encountered with age and other neurodegenerative diseases. However, the focality of the p-tau cortical findings in particular, and the regional distribution, are believed to be unique to CTE. The described clinical features in recent cases are very similar to how depression manifests in middle-aged men and with frontotemporal dementia as the disease progresses. It has not been established that the described tau pathology, especially in small amounts, can cause complex changes in behavior such as depression, substance abuse, suicidality, personality changes, or cognitive impairment. Future studies will help determine the extent to which the neuropathology is causally related to the diverse clinical features.

Objectives: Concussion remains one of the inherent risks of participation in rugby league. While other injuries incurred by rugby league players have been well studied, less focus and attention has been directed towards concussion. Review method: The current review examined all articles published in English from 1900 up to June 2013 pertaining to concussion in rugby league players. Data sources: Publications were retrieved via six databases using the key search terms: rugby league, league, football; in combination with injury terms: athletic injuries, concussion, sports concussion, sports-related concussion, brain concussion, brain injury, brain injuries, mild traumatic brain injury, mTBI, traumatic brain injury, TBI, craniocerebral trauma, head injury and brain damage. Observational, cohort, correlational, cross-sectional and longitudinal studies were all included. Results: 199 rugby league injury publications were identified. 39 (20%) were related in some way to concussion. Of the 39 identified articles, 6 (15%) had the main aim of evaluating concussion, while the other 33 reported on concussion incidence as part of overall injury data analyses. Rugby league concussion incidence rates vary widely from 0.0 to 40.0/1000 playing hours, depending on the definition of injury (time loss vs no time loss). The incidence rates vary across match play versus training session, seasons (winter vs summer) and playing position (forwards vs backs). The ball carrier has been found to be at greater risk for injury than tacklers. Concussion accounts for 29% of all injuries associated with illegal play, but only 9% of injuries sustained in legal play. Conclusions: In comparison with other collision sports, research evaluating concussion in rugby league is limited. With such limited published rugby league data, there are many aspects of concussion that require attention, and future research may be directed towards these unanswered questions.

Prognostic models can guide clinical management and increase statistical power in clinical trials. The availability and adequacy of prognostic models for mild traumatic brain injury (MTBI) is uncertain. The present study aimed to (1) identify and evaluate multivariable prognostic models for MTBI, and (2) determine which pre-, peri-, and early post-injury variables have independent prognostic value in the context of multivariable models. An electronic search of MEDLINE, PsycINFO, PubMed, EMBASE, and CINAHL databases for English-language MTBI cohort studies from 1970-2013 was supplemented by Web of Science citation and hand searching. This search strategy identified 7789 articles after removing duplicates. Of 182 full-text articles reviewed, 26 met eligibility criteria including (1) prospective inception cohort design, (2) prognostic information collected within 1 month post-injury, and (3) 2+variables combined to predict clinical outcome (e.g., post-concussion syndrome) at least 1 month later. Independent reviewers extracted sample characteristics, study design features, clinical outcome variables, predictor selection methods, and prognostic model discrimination, calibration, and cross-validation. These data elements were synthesized qualitatively. The present review found no multivariable prognostic model that adequately predicts individual patient outcomes from MTBI. Suboptimal methodology limits their reproducibility and clinical usefulness. The most robust prognostic factors in the context of multivariable models were pre-injury mental health and early post-injury neuropsychological functioning. Women and adults with early post-injury anxiety also have worse prognoses. Relative to these factors, the severity of MTBI had little long-term prognostic value. Future prognostic studies should consider a broad range of biopsychosocial predictors in large inception cohorts.

Objective: The aim of the current review was to systematically evaluate the available evidence on concussion in Rugby Union and to conduct a meta-analysis of findings regarding the incidence of concussion.

Traumatic brain injury (TBI) is a common condition that is often complicated by neuropsychiatric sequelae that can have major impacts on function and quality of life. An alteration in the sense of smell is recognized as a relatively common complication of TBI; however in clinical practice, this complication may not be sought or adequately characterized. We conducted a systematic review of studies concerned with olfactory functioning following TBI. Our predetermined criteria led to the identification of 25 studies published in English, which we examined in detail. We have tabulated the data from these studies in eight separate tables, beginning with Table 1, which highlights each study's key findings, and we provide a summary/synthesis of the findings in the accompanying results and discussion sections. Despite widely differing methodologies, the studies attest to a high frequency of post-TBI olfactory dysfunction and indicate that its presence can serve as a potential marker of additional structural or functional morbidities. © 2014 Schofield, Moore and Gardner.