المؤلفون: Stefan M. Duma, Qiuting Wen, Larry D. Riggen, Andrew S. Nencka, Thomas W. McAllister, Steven P. Broglio, Nahla M. H. Elsaid, Christopher C. Giza, Andrew R. Mayer, Zikai Lin, Jaroslaw Harezlak, Kevin M. Koch, Jason P. Mihalik, John P. DiFiori, Timothy B. Meier, Kevin M. Guskiewicz, Yu-Chien Wu, Michael McCrea, Stephen M. LaConte, Andrew J. Saykin, Yang Wang, Sourajit M. Mustafi

المصدر: Neurology. 95:e781-e792

مصطلحات موضوعية: Adult, Male, medicine.medical_specialty, Adolescent, Football, Poison control, Corpus callosum, Asymptomatic, Corpus Callosum, White matter, Young Adult, 03 medical and health sciences, 0302 clinical medicine, Physical medicine and rehabilitation, Concussion, medicine, Humans, Brain Concussion, biology, business.industry, Proportional hazards model, Athletes, 030229 sport sciences, medicine.disease, biology.organism_classification, White Matter, Diffusion Magnetic Resonance Imaging, Diffusion Tensor Imaging, medicine.anatomical_structure, Athletic Injuries, Female, Neurology (clinical), medicine.symptom, business, 030217 neurology & neurosurgery, Diffusion MRI

الوصف: ObjectiveTo study longitudinal recovery trajectories of white matter after sports-related concussion (SRC) by performing diffusion tensor imaging (DTI) on collegiate athletes who sustained SRC.MethodsCollegiate athletes (n = 219, 82 concussed athletes, 68 contact-sport controls, and 69 non–contact-sport controls) were included from the Concussion Assessment, Research and Education Consortium. The participants completed clinical assessments and DTI at 4 time points: 24 to 48 hours after injury, asymptomatic state, 7 days after return-to-play, and 6 months after injury. Tract-based spatial statistics was used to investigate group differences in DTI metrics and to identify white-matter areas with persistent abnormalities. Generalized linear mixed models were used to study longitudinal changes and associations between outcome measures and DTI metrics. Cox proportional hazards model was used to study effects of white-matter abnormalities on recovery time.ResultsIn the white matter of concussed athletes, DTI-derived mean diffusivity was significantly higher than in the controls at 24 to 48 hours after injury and beyond the point when the concussed athletes became asymptomatic. While the extent of affected white matter decreased over time, part of the corpus callosum had persistent group differences across all the time points. Furthermore, greater elevation of mean diffusivity at acute concussion was associated with worse clinical outcome measures (i.e., Brief Symptom Inventory scores and symptom severity scores) and prolonged recovery time. No significant differences in DTI metrics were observed between the contact-sport and non–contact-sport controls.ConclusionsChanges in white matter were evident after SRC at 6 months after injury but were not observed in contact-sport exposure. Furthermore, the persistent white-matter abnormalities were associated with clinical outcomes and delayed recovery time.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::faa35ac6b0c96941bfa8d293e5a4daa0
https://doi.org/10.1212/wnl.0000000000009930

المؤلفون: Jonathan T. Macy, Steven W. Zonner, Keisuke Ejima, Keisuke Kawata, Zachary W. Bevilacqua, Sharlene D. Newman, Megan E. Huibregtse

المصدر: Neurology. 93:S28.2-S28

مصطلحات موضوعية: medicine.medical_specialty, Football players, business.industry, American football, Regression analysis, medicine.disease, Serum samples, Inflammatory biomarkers, Physical medicine and rehabilitation, Concussion, Heart rate, medicine, Neurology (clinical), Exertion, business

الوصف: ObjectiveThe purpose of this investigation was to examine the relationships between subconcussive head impact frequency and magnitude and measures of physical exertion and muscle damage.BackgroundSubconcussive head impacts, or impacts that do not present with concussion symptoms, are gaining traction as a major public health concern. However, there is a gap in knowledge about the contribution of physiological variables, such as muscle damage and physical exertion, to neurological measures used to assess subconcussive impact-dependent changes. The unknown contribution of physical exertion and strenuous exercise is often listed as a limitation in field studies of subconcussive head impacts.Design/MethodsFifteen high school football players wore mouthguards installed with triaxial accelerometers and gyroscopes in order to quantify the linear and rotational accelerations of every head impact sustained throughout one season (practices and games). Additionally, serum samples were collected at twelve time points (pre-season, pre- and post-competition for five in-season games, and post-season) and assayed for CK-MM, the skeletal muscle-specific isoenzyme of creatine kinase. Subjects wore heart rate monitors during the five games, and heart rate data were used to estimate physical exertion in terms of excess post-exercise oxygen consumption (EPOC).ResultsMixed-effect regression modeling (MRM) showed significant and positive associations between CK-MM and subconcussive head impact kinematic variables, in addition to a significant and positive association between CK-MM and EPOC. The models were adjusted for cumulative head impact exposures up to each game and the pre-season serum CK-MM levels, when applicable.ConclusionsWhen investigating subconcussive head impacts, the effects of muscle damage should be considered when using correlated outcome measures, such as inflammatory biomarkers and vestibular assessments.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::df95d999dfdb48413f815363eb934fb8
https://doi.org/10.1212/01.wnl.0000581108.75442.9b

المؤلفون: Baxter B. Allen, Steven Karceski

المصدر: Neurology. 88:e74-e77

مصطلحات موضوعية: medicine.medical_specialty, Injury control, Head impact, Poison control, Human factors and ergonomics, Football, medicine.disease, Suicide prevention, Occupational safety and health, 03 medical and health sciences, 0302 clinical medicine, Physical medicine and rehabilitation, 030225 pediatrics, Injury prevention, medicine, Neurology (clinical), Medical emergency, Psychology, human activities, 030217 neurology & neurosurgery

الوصف: In their article “Symptoms from repeated intentional and unintentional head impact in soccer players,” Stewart et al.1 explore the link between heading the soccer ball and the development of neurologic symptoms. In contact sports, most notably football,2 there is a link between so-called subconcussive hits and the development of long-term neurologic symptoms. The authors, in previous work,3 saw a similar link between heading the ball in soccer and poorer scores on a memory function test.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::ccffdcfd2caacf5db06c6149a5bd80e3
https://doi.org/10.1212/wnl.0000000000003669

المؤلفون: Sergey Samorezov, Michael McCrea, John Humm, Adam J. Bartsch, Alok S. Shah, Jay L. Alberts, Brian D. Stemper, Vincent J. Miele, Edward C. Benzel, Rajiv Dama

المصدر: Neurology. 91:S1.2-S1

مصطلحات موضوعية: medicine.medical_specialty, business.product_category, biology, Athletes, American football, Football, medicine.disease, biology.organism_classification, Test (assessment), Athletic training, Hybrid III, Physical medicine and rehabilitation, Concussion, medicine, Neurology (clinical), Mouthguard, business, Psychology

الوصف: BackgroundAlthough concussion continues to be a major source of acute and chronic injury in automotive, athletic and military arenas, concussion injury mechanisms and risk functions are ill-defined. To overcome this knowledge gap, we have developed, tested and deployed a head impact monitoring mouthguard (IMM) system. The IMM system was first calibrated in 731 laboratory tests against Hybrid III and NOCSAE headforms with Reference kinematic sensors. Next, during on-field play involving n = 54 amateur American athletes in football and boxing, there were tens of thousands of kinematic signatures collected by the IMM. A total of 890 true positive head impacts were confirmed using a combination of signal processing and NINDS/NIH Common Data Elements methods [1].MethodsLaboratory tests were conducted using an American football helmet (n = 451), padded headform (n = 99) or bare head (n = 181). The IMM included kinematics sensors, along with associated microprocessor, battery and data transmission. Peak linear acceleration (PLA) at headform center of gravity (cg) was compared in each test between Reference and IMM.54 athletes in football and boxing aged 11 to 22 were consented. Impact with cg PLA as low as 7 g were collected during practices/games.Results/discussionLaboratory data fit a linear model close to ideal y = x + 0, R2 = 1. There were >100,000 triggering events, with 890 true positives. “False positives” contained high frequency data not indicative of head motion. The median/99th percentile of (PLA) and (PAA) were 20/50 g, and 1700 rad/s2/4600 rad/s2. There were no diagnosed concussions. One athlete was removed by athletic training staff after a significant head impact.ConclusionsIn the future, head impact dynamics data must be correlated with sensitive and specific assessments of cognitive, executive, vision and balance parameters in order to determine the concussion assessment threshold.Disclosures: Dr. Bartsch has nothing to disclose. Dr. Dama has nothing to disclose. Dr. Samorezov has nothing to disclose. Dr. Alberts has received personal compensation for activities with Boston Scientific Corporation. Dr. Benzel has nothing to disclose. Dr. Miele has nothing to disclose. Dr. Shah has nothing to disclose. Dr. Humm has nothing to disclose. Dr. McCrea has nothing to disclose. Dr. Stemper has nothing to disclose.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::8eb16fd93e1366b648b3cc45e2e1f097
https://doi.org/10.1212/01.wnl.0000550620.51257.e3

المؤلفون: Thomas Blaine Hoshizaki, Michael D. Gilchrist, Clara Karton

المصدر: Neurology. 91:S1.1-S1

مصطلحات موضوعية: medicine.medical_specialty, Percentile, Event type, business.industry, American football, Football, Head trauma, Drop tower, Hybrid III, Physical medicine and rehabilitation, Medicine, Neurology (clinical), business, Gage factor

الوصف: In American football repetitive brain trauma is associated with high risk of neurologic disorders. Head contact is integral to the game, resulting in high frequency of head contacts during a game/season. Low energy impacts that do not manifest signs recognized as injury still present metabolic and/or physiologic changes within the brain. The purpose was to estimate player position specific brain trauma profiles based on strain magnitude and impact frequency. Head impacts from 32 game films of professional football were documented and categorized based on event type, head location, and velocity for 8 positions. Inbound velocity was calculated using Kinovea 0.8.20 software. Events were reconstructed using 50th percentile Hybrid III headform, unbiased neckform, linear impactor (collisions) and monorail drop tower (falls). Maximum principal strain (MPS) within the cerebrum was calculated using UCDBTM. Frequency [p < 0.0005] and magnitude [p < 0.0005] were significantly different between the 8 positions. No significant differences in frequencies between the following; quarterback, wide receiver, and defensive back; running back, tight end, and linebacker; and between offensive and defensive linemen. Approximately 60% of documented impacts were received by linemen and tight end. The magnitudes of impacts experienced by quarterbacks were significantly different to all positions excluding wide receiver and defensive back. Wide receiver experienced significantly different magnitudes than both linemen; and differences were found between offensive linemen and defensive back. Approximately 95% of impacts experienced by linemen were below 17% MPS. Conversely, over 90% of impacts documented for quarterback were above moderate strain magnitudes (>17%). Results show risks of repetitive trauma and injury vary with position; some experience high frequency impacts of low magnitude while others receive lower hit counts of higher magnitudes. Findings showed that tight end and running back are particularly risky with relatively high brain strain magnitudes coupled with high frequency making them susceptible to high trauma loads.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::615e231fd77325c5e84e1da13c40ec51
https://doi.org/10.1212/wnl.0000000000006599

المؤلفون: Vincent J. Miele, Sergey Samorezov, Adam J. Bartsch, Edward C. Benzel

المصدر: Neurology. 93:S10.1-S10

مصطلحات موضوعية: medicine.medical_specialty, High energy, Head (linguistics), Head impact, media_common.quotation_subject, Fidelity, American football, Concussive injury, medicine.disease, medicine.anatomical_structure, Physical medicine and rehabilitation, Concussion, Forehead, medicine, Neurology (clinical), Psychology, media_common

الوصف: ObjectiveThe aim of this study was to investigate head impact doses in American football. We analyzed time-synchronized video and data collected during n = 445 player-games of American football resulting in 2851video-verified impacts. Cases where a player sustained impacts and on video was demonstrably witnessed to meet the NFL’s “No-go” criteria were analyzed in-depth.BackgroundIn 2011, after reviewing scalar on-field kinematics data leading concussion clinicians concluded “Recent studies suggest that a concussive injury threshold is elusive, and may, in fact, be irrelevant when predicting the clinical outcome”.1 It is likely that higher fidelity estimates of spatial and temporal impact parameters will clarify the currently unclear impact dose-response relationship.Design/MethodsA total of 2851 video-verified head impacts were identified from 445 player-games. Each event was time-synchronized to video. Any events collected when the athlete was not being impacted in the head were discarded. The remaining true positive events were scrutinized based on published methods to confirm a head impact occurred in the video and the computed motion was physically realistic and matched the video.ResultsWe found a median of 5 video-verified head impacts per player-game, which is far fewer than published studies without video verification.11 For the four players with “No-go” impacts, all were to the side/rear. Coronal plane impact sensitivity has been a hypothesized clinical injury mechanism12 and our results support that hypothesis.ConclusionsWe did not see high PLA/PAA impacts without obvious player “No-go” observations. This finding disagrees with other studies that have reported high PLA/PAA impacts without any demonstrable “No-go” observations13. High energy impacts to the side and rear of the head are more damaging than similar magnitude impacts to the forehead. Armed with this knowledge, clinicians should have more fidelity in their understanding of real-time impact location and severity, and how it relates to athlete concussion risk.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::6dc37b04d11d6a54361075674356d918
https://doi.org/10.1212/01.wnl.0000580920.17339.01

المؤلفون: Joel D. Stitzel, Joseph A. Maldjian, Derek K. Jones, Christopher T. Whitlow, Mirellie Kelley, Jillian E. Urban, Alexander K. Powers

المصدر: Neurology. 91:S2.2-S2

مصطلحات موضوعية: medicine.medical_specialty, biology, Athletes, Head impact, business.industry, Context (language use), Football, medicine.disease, biology.organism_classification, Physical medicine and rehabilitation, Quartile, Concussion, medicine, Linear acceleration, Injury mechanisms, Neurology (clinical), business, human activities

الوصف: Approximately 1.1–1.9 million sport-related concussions among athletes ≤18 years of age occur annually in the United States, but there is limited understanding of the biomechanics and injury mechanisms associated with concussions among lower level football athletes. Therefore, the objective of this study was to combine biomechanical head impact data with video analysis to characterize youth and HS football concussion injury mechanisms. Head impact data were collected from athletes participating on 22 youth and 6 HS football teams between 2012 and 2017. Video was recorded, and head impact data were collected during all practices and games by instrumenting players with the Head Impact Telemetry (HIT) System. For each clinically diagnosed concussion, a video abstraction form was completed, which included questions concerning the context in which the injury occurred. Linear acceleration, rotational acceleration, and impact location were used to characterize the concussive event and each injured athlete's head impact exposure on the day of the concussion. A total of 9 (5 HS and 4 youth) concussions with biomechanics and video of the event were included in this study. The mean [range] linear and rotational acceleration of the concussive impacts were 62.9 [29.3–118.4] g and 3,056.7 [1,046.8–6,954.6] rad/s2, respectively. Concussive impacts were the highest magnitude impacts for 6 players and in the top quartile of impacts for 3 players on the day of injury. Concussions occurred in both practices (N = 4) and games (N = 5). The most common injury contact surface was helmet-to-helmet (N = 5), followed by helmet-to-ground (N = 3) and helmet-to-body (N = 1). All injuries occurred during player-to-player contact scenarios, including tackling (N = 4), blocking (N = 4), and collision with other players (N = 1). The biomechanics and injury mechanisms of concussions varied among athletes in our study; however, concussive impacts were among the highest severity for each player and all concussions occurred as a result of player-to-player contact.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::cd605731c48b5ece93ea27a268b96df3
https://doi.org/10.1212/01.wnl.0000550623.36010.20

المؤلفون: Thomas Blaine Hoshizaki, Janie Cournoyer

المصدر: Neurology. 91:S3.1-S3

مصطلحات موضوعية: Angular acceleration, medicine.medical_specialty, business.industry, media_common.quotation_subject, Severity of injury, American football, 030229 sport sciences, Brain tissue, Kinematics, 03 medical and health sciences, Hybrid III, 0302 clinical medicine, Physical medicine and rehabilitation, Linear acceleration, Medicine, 030212 general & internal medicine, Neurology (clinical), Consciousness, business, media_common

الوصف: IntroductionLoss of consciousness (LOC) occurs with approximately 8 percent of concussions in professional American football and has been associated with severity of injury (1, 2). However it is unknown how LOC relates to severity of head impact responses. The purpose of this study was to compare the head accelerations and brain tissue deformation between cases of concussions with and without LOC in elite American football to inform prevention strategies.MethodsConcussive injuries with and without LOC from helmet-to-helmet and shoulder collisions as well as falls in elite American football were reconstructed in laboratory using hybrid III headform to obtain peak linear and rotational acceleration and maximum principal strain, cumulative strain damage at 10%, and strain rate metrics in 5 brain regions associated with loss of consciousness.ResultsImpact velocity, peak linear and rotational acceleration were greater in the LOC group than the no LOC group. The brain tissue deformation metrics were greater in the LOC group than the no LOC group. Linear acceleration was most predictive for cases of helmet-to-helmet collisions whereas shoulder collisions were best predicted by rotational acceleration. The best overall predictor was impact velocity.Discussion/conclusionThe presence of a loss of consciousness in concussive impacts is a result of greater magnitude of brain tissue trauma. This was primarily caused by greater impact velocities in head impacts leading to LOC. Rules aiming at mitigating this aspect of the game would decrease the risk of a loss of consciousness in this sport. Each type of events resulted in different values of kinematic data and brain tissue deformation, which suggests that studies evaluating risk of concussions based 1 type of event cannot be generalized.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::3accc891bacd2e8dd0d511b91377c1e8
https://doi.org/10.1212/01.wnl.0000550687.39137.ef

المؤلفون: Thomas Blaine Hoshizaki, Bianca Brigitte Rock

المصدر: Neurology. 91:S2.1-S2

مصطلحات موضوعية: Percentile, medicine.medical_specialty, biology, Head impact, Athletes, Head injury, biology.organism_classification, medicine.disease, Hybrid III, Chronic traumatic encephalopathy, Physical medicine and rehabilitation, Football soccer, Elite, medicine, Neurology (clinical), Psychology, human activities

الوصف: IntroductionTrauma related neuropathologies including recent reports involving chronic traumatic encephalopathy (CTE) in 8 soccer players have been concerning. Purposeful sub-concussive head impacts, known as headers, are an integral part of the game. The purpose of this study was to describe dynamic head response and brain tissue strains for front ball-to-head impacts in elite soccer.MethodsVideo analysis thirteen (13) Champion's League soccer footage was completed to establish reconstruction parameters of head impact events. Analysis of 5 (5) front ball-to-head events were reconstructed using a Hybrid III 50th percentile headform and a pneumatic linear impactor. The University College Dublin Brain Trauma Model was used to calculate maximum principal strain (MPS).Results and discussionRecorded head impact velocities during elite soccer game play were 3.5–23.0 m/s. Most purposeful head-to-ball impacts occurred on the front-temporal region of the head (66.4%) at 0–15 degrees of cervical flexion. There was an average of 1.5 unintentional head impacts and 62.2 headers per game; 49.6% of headers occurred at an inbound velocity below 10 m/s. The lowest velocity reconstructed was 4.7 m/s, yielding 12.8 g and 604 rad/s2 for peak resultant linear and rotational accelerations, respectively; the MPS for this impact was 0.09. Neurophysiologic changes and functional impairment have been reported in past research on sub-concussive impacts with 5%–15% strain. The mean 0.11 MPS yielded in this study reflects a potential for these changes in elite soccer athletes.ConclusionThe main objective of this analysis was to identify impact characteristics and quantify dynamic cerebral response and brain tissue deformation in elite soccer game play. Further research must include cervical muscle activation, the level of play and player position, inbound ball-to-head velocities during different game play events and appropriate impact characteristics to appropriately characterize risk of injury in the attempts of mitigating risk of head injury during soccer game play.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::0d546cac45866d4cbdf4570951bb2d79
https://doi.org/10.1212/01.wnl.0000550622.28386.5a

المؤلفون: Bajaj Nikesh

المصدر: Neurology. 91:S23.4-S24

مصطلحات موضوعية: medicine.medical_specialty, business.industry, American football, League, medicine.disease, Return to play, Physical medicine and rehabilitation, Concussion, Health care, medicine, Neurology (clinical), Psychology, business, human activities

الوصف: Concussion evaluation and treatment has been widely less widely publicized in soccer vs American football. However, a recent assessment found that in the previous FIFA World Cup in 2014, 63% of events when players involved in head collisions were not assessed by sideline healthcare personnel within the 64 matches of the tournament. The upcoming 2018 FIFA World Cup should be approached with a more critical eye in order to improve the rate of concussion assessment in head collisions. US Soccer National Team's Concussion policy “players who are suspected of having sustained a concussion shall be removed from play immediately and evaluated by team medical staff.” Not all head collisions are required to be examined and a physician is not required to perform the sideline evaluation. Since the start of the 2018 Major League Soccer season, at least 2 incidents of concussion diagnosis were instances which an initial evaluation allowed the player to return to play when a concussion diagnosis was made later. A detailed examination of professional soccer both on the American and World stage exposes gaps in concussion policy that must be addressed to improve the approach to athlete brain health.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::3732c25e40f403ed8c6f9a42647c942a
https://doi.org/10.1212/01.wnl.0000550650.66298.fb