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Bartsch A, Rooks TF. Head Impacts in the Top 1% by Peak Linear Acceleration and/or Work Cause Immediate Concussion Signs and 'Check Engine' Responses in Military Service Members and Civilian Athletes. Ann Biomed Eng 2024; 52:2780-2793. [PMID: 37926788 DOI: 10.1007/s10439-023-03393-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/21/2023] [Indexed: 11/07/2023]
Abstract
PURPOSE Historically, head impact monitoring sensors have suffered from single impact measurement errors, leading to their data described by clinical experts as 'clinically irrelevant.' The purpose of this study was to use an accurate impact monitoring mouthguard system and (1) define head impact distributions for military service members and civilians and (2) determine if there was a dose-response relationship between accurately measured head impact magnitudes versus observations of concussion signs. METHODS A laboratory-calibrated commercial impact monitoring mouthguard system, along with video and hardware to confirm the sensor was on the teeth during impacts, was used to acquire 54,602 head acceleration events (HAE) in 973 military and civilian subjects over 3,449 subject days. RESULTS There were 17,551 head impacts (32% of HAE) measured with peak linear acceleration (PLA) > 10 g and 37,051 low-g events (68% of HAE) in the range of activities of daily living < 10 g PLA. The median of all HAE and of all head impacts was 8 g/15 g PLA and 1 J/4 J Work, respectively. The top 1% of head impacts were above 47 g and 32 J, respectively. There were fifty-six (56) head impacts where at least one clinical indicator of a concussion sign was observed. All the clinical indicator impacts were in the top 1% by magnitude of PLA, Work, or both. The median magnitude of these 'check engine' impacts was 58 g and 48 J. This median magnitude was substantially larger than the median of all HAE as well as the median of all head impacts. CONCLUSION This study shows a correlation between single head impacts in the top 1% by peak linear acceleration and/or Work and clinical indicators of concussion signs in civilians and military service members.
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Affiliation(s)
- Adam Bartsch
- Prevent Biometrics, 4600 West 77th, Minneapolis, MN, 55435, USA.
| | - Tyler F Rooks
- US Army Aeromedical Research Laboratory, Fort Rucker, AL, USA
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2
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Emerson HN, Claiborne TL, Liberi V, Kelleran KJ. A comparison of sub-concussive impact attenuating capabilities of ice hockey helmets with and without XRD foam. J Sci Med Sport 2024; 27:697-701. [PMID: 39013696 DOI: 10.1016/j.jsams.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 03/25/2024] [Accepted: 05/14/2024] [Indexed: 07/18/2024]
Abstract
OBJECTIVES To compare the impact attenuating capabilities between ice hockey helmets manufactured with and without XRD impact protection foam, worn with and without a XRD skullcap, at reducing sub-concussive head accelerations. DESIGN Quasi-experimental laboratory. METHODS Ice hockey helmets were fit onto a Hybrid III 50th Head Form Head and dropped 25 times onto the left temporal side for each condition: XRD foam helmet, XRD foam helmet with XRD skullcap adjunct, non-XRD foam helmet, and non-XRD foam helmet with XRD skullcap adjunct. The helmets were dropped from a height that resulted in sub-concussive linear accelerations (25-80 g's). Using a tri-axial accelerometer, peak linear accelerations (g) were measured, and the average was used to compare impact attenuation properties across the four conditions. RESULTS The highest linear accelerations were observed in the XRD foam helmet without skullcap (32.97 ± 0.61 g) and were significantly greater (p < 0.001) than the XRD helmet with skullcap (21.38 ± 0.76 g). The helmet without XRD foam elicited the lowest peak linear accelerations (16.10 ± 0.73 g) which were significantly lower than the XRD foam helmet regardless of whether the skullcap was added (p < 0.001). CONCLUSIONS Although sub-concussive loads are potentially just as dangerous, much of the research regarding helmet and skullcap efficacy appears to be at high concussive impacts; <70 g's. The findings suggest that helmets with incorporated XRD foam, either within the design or added as an adjunct, are less effective at attenuating linear accelerations at sub-concussive levels than the low-density foam helmet.
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Affiliation(s)
- Hannah N Emerson
- Department of Exercise Science & Athletic Training, Adrian College, United States of America.
| | - Tina L Claiborne
- Department of Exercise Science & Athletic Training, Adrian College, United States of America
| | - Victor Liberi
- Department of Exercise Science & Athletic Training, Adrian College, United States of America
| | - Kyle J Kelleran
- Department of Emergency Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, United States of America
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Otsubo S, Shigemori Y, Endo S, Fukushima H, Tachihara M, Goto K, Tsurusaki R, Otsuka N, Masuda K, Zhang Y. Characteristics of Intracranial Kinetic Loads When Sports-Related Concussion Occurs in Men's Rhythmic Gymnastics. Brain Sci 2024; 14:835. [PMID: 39199526 PMCID: PMC11353157 DOI: 10.3390/brainsci14080835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 07/29/2024] [Accepted: 08/09/2024] [Indexed: 09/01/2024] Open
Abstract
This study aimed to clarify the differences between the previously reported mechanisms of sports-related concussion (SRC) injuries without a loss of consciousness in contact and collision sports and the mechanisms of SRC injuries in our cases. Based on two videos of SRC injuries occurring during a men's rhythmic gymnastics competition (three people were injured), the risk of SRC occurrence was estimated from various parameters using a multibody analysis and eight brain injury evaluation criteria. In the present study, the three SRC impacts that occurred in men's rhythmic gymnastics showed significant characteristics in duration compared to previously reported cases in the contact sports. This suggests that the occurrence of SRC may have been caused by a different type of impact from that which causes SRC in contact sports (e.g., tackling). In addition, calculation of the strain indicating the rate of brain deformation suggested a risk of nerve swelling in all cases involving type 2 axonal injuries. Therefore, when reexamining sports-related head injuries, it is important to recognize the characteristics and mechanisms of SRC that occur in each different sport, as well as the symptoms and course of SRC after injury.
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Affiliation(s)
- Shunya Otsubo
- Center for Education and Innovation, Sojo University, Kumamoto 860-0082, Japan;
| | - Yutaka Shigemori
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan;
- Department of Neurological Surgery, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan; (H.F.); (M.T.); (K.G.); (K.M.)
| | - Sena Endo
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan; (S.E.); (Y.Z.)
| | - Hiroshi Fukushima
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan; (H.F.); (M.T.); (K.G.); (K.M.)
| | - Muneyuki Tachihara
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan; (H.F.); (M.T.); (K.G.); (K.M.)
| | - Kyosuke Goto
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan; (H.F.); (M.T.); (K.G.); (K.M.)
- Department of Rehabilitation, Fukuoka University Hospital, Fukuoka 814-0180, Japan
| | - Rino Tsurusaki
- Faculty of Human Sciences, Kyushu Sangyo University, Fukuoka 813-0004, Japan;
| | - Nana Otsuka
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan;
| | - Kentaro Masuda
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka 814-0180, Japan; (H.F.); (M.T.); (K.G.); (K.M.)
| | - Yuelin Zhang
- Faculty of Science and Technology, Sophia University, Tokyo 102-8554, Japan; (S.E.); (Y.Z.)
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Lau JS, Lust CAC, Lecques JD, Hillyer LM, Mountjoy M, Kang JX, Robinson LE, Ma DWL. n-3 PUFA ameliorate functional outcomes following repetitive mTBI in the fat-1 mouse model. Front Nutr 2024; 11:1410884. [PMID: 39070251 PMCID: PMC11272621 DOI: 10.3389/fnut.2024.1410884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/28/2024] [Indexed: 07/30/2024] Open
Abstract
Purpose Repeated mild traumatic brain injuries (mTBI) are a continuing healthcare concern worldwide, given its potential for enduring adverse neurodegenerative conditions. Past research suggests a potential protective effect of n-3 polyunsaturated fatty acids (PUFA) in experimental models of mTBI. The aim of this study was to investigate whether the neuroprotective benefits of n-3 PUFA persist following repetitive weight drop injury (WDI). Methods Male fat-1 mice (n = 12), able to endogenously convert n-6 PUFA to n-3 PUFA, and their wild type (WT) counterparts (n = 12) were maintained on a 10% w/w safflower diet. At 9-10 weeks of age, both groups received one mild low-impact WDI on the closed cranium daily, for three consecutive days. Following each WDI, time to righting reflex and seeking behaviour were measured. Neurological recovery, cognitive, motor, and neurobehavioural outcomes were assessed using the Neurological Severity Score (NSS) over 7 days (168 h) post-last WDI. Brains were assessed for cerebral microhemorrhages by Prussian blue and cellular damage by glial fibrillary acidic protein (GFAP) staining. Results Fat-1 mice exhibited significantly faster righting reflex and seeking behaviour time, and lower mean NSS scores and at all post-WDI time points (p ≤ 0.05) compared to WT mice. Immunohistochemistry showed no significant difference in presence of cerebral microhemorrhage however, fat-1 mice had significantly lower GFAP staining in comparison to WT mice (p ≤ 0.05). Conclusion n-3 PUFA is effective in restoring cognitive, motor, and behavioural function after repetitive WDI, which may be mediated through reduced cellular damage of the brain.
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Affiliation(s)
- Jessi S. Lau
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Cody A. C. Lust
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | | | - Lyn M. Hillyer
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Margo Mountjoy
- Department of Family Medicine, McMaster University, Hamilton, ON, Canada
| | - Jing X. Kang
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Lindsay E. Robinson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - David W. L. Ma
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Tooby J, Till K, Gardner A, Stokes K, Tierney G, Weaving D, Rowson S, Ghajari M, Emery C, Bussey MD, Jones B. When to Pull the Trigger: Conceptual Considerations for Approximating Head Acceleration Events Using Instrumented Mouthguards. Sports Med 2024; 54:1361-1369. [PMID: 38460080 PMCID: PMC11239719 DOI: 10.1007/s40279-024-02012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2024] [Indexed: 03/11/2024]
Abstract
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.
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Affiliation(s)
- James Tooby
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK.
| | - Kevin Till
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Leeds Rhinos Rugby League Club, Leeds, UK
| | - Andrew Gardner
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
| | - Keith Stokes
- Centre for Health and Injury and Illness Prevention in Sport, University of Bath, Bath, UK
- Medical Services, Rugby Football Union, Twickenham, UK
| | - Gregory Tierney
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Sport and Exercise Sciences Research Institute, School of Sport, Ulster University, Belfast, UK
| | - Daniel Weaving
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - Steve Rowson
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
- Leeds Beckett University, Leeds, UK
| | - Mazdak Ghajari
- Dyson School of Design Engineering, Imperial College London, London, UK
| | - Carolyn Emery
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Departments of Pediatrics and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Melanie Dawn Bussey
- School of Physical Education Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Ben Jones
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Division of Physiological Sciences, Department of Human Biology, Faculty of Health Sciences, University of Cape Town and Sports Science Institute of South Africa, Cape Town, South Africa
- School of Behavioural and Health Sciences, Faculty of Health Sciences, Australian Catholic University, Brisbane, QLD, Australia
- Rugby Football League, England Performance Unit, Red Hall, Leeds, UK
- Premiership Rugby, London, UK
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Hoogenboom WS, Rubin TG, Ambadipudi K, Cui MH, Ye K, Foster H, Elkouby E, Liu J, Branch CA, Lipton ML. Evolving brain and behaviour changes in rats following repetitive subconcussive head impacts. Brain Commun 2023; 5:fcad316. [PMID: 38046094 PMCID: PMC10691880 DOI: 10.1093/braincomms/fcad316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 09/26/2023] [Accepted: 11/19/2023] [Indexed: 12/05/2023] Open
Abstract
There is growing concern that repetitive subconcussive head impacts, independent of concussion, alter brain structure and function, and may disproportionately affect the developing brain. Animal studies of repetitive subconcussive head impacts are needed to begin to characterize the pathological basis and mechanisms underlying imaging and functional effects of repetitive subconcussive head impacts seen in humans. Since repetitive subconcussive head impacts have been largely unexplored in animals, we aimed to characterize the evolution of imaging, behavioural and pathological effects of repetitive subconcussive head impacts in awake adolescent rodents. Awake male and female Sprague Dawley rats (postnatal Day 35) received 140 closed-head impacts over the course of a week. Impacted and sham-impacted animals were restrained in a plastic cone, and unrestrained control animals were included to account for effects of restraint and normal development. Animals (n = 43) underwent repeated diffusion tensor imaging prior to and over 1 month following the final impact. A separate cohort (n = 53) was assessed behaviourally for fine motor control, emotional-affective behaviour and memory at acute and chronic time points. Histological and immunohistochemical analyses, which were exploratory in nature due to smaller sample sizes, were completed at 1 month following the final impact. All animals tolerated the protocol with no overt changes in behaviour or stigmata of traumatic brain injury, such as alteration of consciousness, intracranial haemorrhage or skull fracture. We detected longitudinal, sex-dependent diffusion tensor imaging changes (fractional anisotropy and axial diffusivity decline) in corpus callosum and external capsule of repetitive subconcussive head impact animals, which diverged from both sham and control. Compared to sham animals, repetitive subconcussive head impact animals exhibited acute but transient mild motor deficits. Repetitive subconcussive head impact animals also exhibited chronic anxiety and spatial memory impairment that differed from the control animals, but these effects were not different from those seen in the sham condition. We observed trends in the data for thinning of the corpus callosum as well as regions with elevated Iba-1 in the corpus callosum and cerebral white matter among repetitive subconcussive head impact animals. While replication with larger study samples is needed, our findings suggest that subconcussive head impacts cause microstructural tissue changes in the developing rat brain, which are detectable with diffusion tensor imaging, with suggestion of correlates in tissue pathology and behaviour. The results point to potential mechanisms underpinning consequences of subconcussive head impacts that have been described in humans. The congruence of our imaging findings with human subconcussive head impacts suggests that neuroimaging could serve as a translational bridge to advance study of injury mechanisms and development of interventions.
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Affiliation(s)
- Wouter S Hoogenboom
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
- Department of Clinical Investigation, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
- Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
| | - Todd G Rubin
- Department of Neurology, Icahn School of Medicine at Mount Sinai, NewYork, NY 10029, USA
| | - Kamalakar Ambadipudi
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
- Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
| | - Min-Hui Cui
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
- Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
| | - Kenny Ye
- Department of Epidemiology & Population Health, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
| | - Henry Foster
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
| | - Esther Elkouby
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
| | - Jinyuan Liu
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
| | - Craig A Branch
- The Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10641, USA
- Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10461, USA
| | - Michael L Lipton
- Department of Radiology, Columbia University Irving Medical Center, NewYork, NY 10032, USA
- Department of Biomedical Engineering, Columbia University, NewYork, NY 10032, USA
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Smoliga JM, Deshpande SK, Binney ZO. Interaction of Surface Type, Temperature, and Week of Season on Concussion Risk in the National Football League: A Bayesian Analysis. Epidemiology 2023; 34:807-816. [PMID: 37732833 DOI: 10.1097/ede.0000000000001657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
BACKGROUND Artificial turf fields and environmental conditions may influence sports concussion risk, but existing research is limited by uncontrolled confounding factors, limited sample size, and the assumption that risk factors are independent of one another. The purpose of this study was to examine how playing surface, time of season, and game temperature relate to diagnosed concussion risk in the National Football League (NFL). METHODS This retrospective cohort study examined data from the 2012 to the 2019 NFL regular season. We fit Bayesian negative binomial regression models to relate how playing surface, game temperature, and week of the season independently related to diagnosed concussion risk and any interactions among these factors. RESULTS We identified 1096 diagnosed concussions in 1830 games. There was a >99% probability that concussion risk was reduced on grass surface (median incidence rate ratio [IRR] = 0.78 [95% credible interval: 0.68, 0.89]), >99% probability that concussion risk was lower at higher temperatures (IRR = 0.85 [0.76,0.95] for each 7.9 °C), and >91% probability that concussion risk increased with each week of the season (IRR = 1.02 [1.00,1.04]). There was an >84% probability for a surface × temperature interaction (IRR = 1.01 [0.96, 1.28]) and >75% probability for a surface × week interaction (IRR = 1.02 [0.99, 1.05]). CONCLUSIONS Diagnosed concussion risk is increased on artificial turf compared with natural grass, and this is exacerbated in cold weather and, independently, later in the season. The complex interplay between these factors necessitates accounting for multiple factors and their interactions when investigating sports injury risk factors and devising mitigation methods.
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Affiliation(s)
- James M Smoliga
- From the Department of Physical Therapy, One University Parkway, High Point University, High Point, NC
- Doctor of Physical Therapy Program (Seattle), Tufts University School of Medicine, Boston, MA
| | - Sameer K Deshpande
- Department of Statistics, University of Wisconsin, 7225B Medical Sciences Center, Madison, WI
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Simulated Astronaut Kinematics and Injury Risk for Piloted Lunar Landings and Launches While Standing. Ann Biomed Eng 2022; 50:1857-1871. [PMID: 35818016 DOI: 10.1007/s10439-022-03002-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/27/2022] [Indexed: 12/30/2022]
Abstract
During future lunar missions, astronauts may be required to pilot vehicles while standing, and the associated kinematic and injury response is not well understood. In this study, we used human body modeling to predict unsuited astronaut kinematics and injury risk for piloted lunar launches and landings in the standing posture. Three pulses (2-5 g; 10-150 ms rise times) were applied in 10 directions (vertical; ± 10-degree offsets) for a total of 30 simulations. Across all simulations, motion envelopes were computed to quantify displacement of the astronaut's head (max 9.0 cm forward, 7.0 cm backward, 2.1 cm upward, 7.3 cm downward, 2.4 cm lateral) and arms (max 25 cm forward, 35 cm backward, 15 cm upward, 20 cm downward, 20 cm lateral). All head, neck, lumbar, and lower extremity injury metrics were within NASA's tolerance limits, except tibia compression forces (0-1543 N upper tibia; 0-1482 N lower tibia; tolerance-1350 N) and revised tibia index (0.04-0.58 upper tibia; 0.03-0.48 lower tibia; tolerance-0.43) for the 2.7 g/150 ms pulse. Pulse magnitude and duration contributed over 80% to the injury metric values, whereas loading direction contributed less than 3%. Overall, these simulations suggest piloting a lunar lander vehicle in the standing posture presents a tibia injury risk which is potentially outside NASA's acceptance limits and warrants further investigation.
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9
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Rowson B, Duma SM. A Review of Head Injury Metrics Used in Automotive Safety and Sports Protective Equipment. J Biomech Eng 2022; 144:1140295. [PMID: 35445266 DOI: 10.1115/1.4054379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Indexed: 11/08/2022]
Abstract
Despite advances in the understanding of human tolerances to brain injury, injury metrics used in automotive safety and protective equipment standards have changed little since they were first implemented nearly a half-century ago. Although numerous metrics have been proposed as improvements over the ones currently used, evaluating the predictive capability of these metrics is challenging. The purpose of this review is to summarize existing head injury metrics that have been proposed for both severe head injuries, such as skull fractures and traumatic brain injuries (TBI), and mild traumatic brain injuries (mTBI) including concussions. Metrics have been developed based on head kinematics or intracranial parameters such as brain tissue stress and strain. Kinematic metrics are either based on translational motion, rotational motion, or a combination of the two. Tissue-based metrics are based on finite element model simulations or in vitro experiments. This review concludes with a discussion of the limitations of current metrics and how improvements can be made in the future.
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Affiliation(s)
- Bethany Rowson
- Institute for Critical Technology and Applied Science (ICTAS), Virginia Tech, 437 Kelly Hall, 325 Stanger Street, Blacksburg, VA 24061
| | - Stefan M Duma
- Institute for Critical Technology and Applied Science (ICTAS), Virginia Tech, 410H Kelly Hall, 325 Stanger Street, Blacksburg, VA 24061
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Consensus Head Acceleration Measurement Practices (CHAMP): Laboratory Validation of Wearable Head Kinematic Devices. Ann Biomed Eng 2022; 50:1356-1371. [PMID: 36104642 PMCID: PMC9652295 DOI: 10.1007/s10439-022-03066-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/25/2022] [Indexed: 12/15/2022]
Abstract
Wearable devices are increasingly used to measure real-world head impacts and study brain injury mechanisms. These devices must undergo validation testing to ensure they provide reliable and accurate information for head impact sensing, and controlled laboratory testing should be the first step of validation. Past validation studies have applied varying methodologies, and some devices have been deployed for on-field use without validation. This paper presents best practices recommendations for validating wearable head kinematic devices in the laboratory, with the goal of standardizing validation test methods and data reporting. Key considerations, recommended approaches, and specific considerations were developed for four main aspects of laboratory validation, including surrogate selection, test conditions, data collection, and data analysis. Recommendations were generated by a group with expertise in head kinematic sensing and laboratory validation methods and reviewed by a larger group to achieve consensus on best practices. We recommend that these best practices are followed by manufacturers, users, and reviewers to conduct and/or review laboratory validation of wearable devices, which is a minimum initial step prior to on-field validation and deployment. We anticipate that the best practices recommendations will lead to more rigorous validation of wearable head kinematic devices and higher accuracy in head impact data, which can subsequently advance brain injury research and management.
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11
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Wusk Z, Rowson S. Football Shoulder Pad Design and Its Effect on Head Kinematics in Shoulder-to-Helmet Impacts. Ann Biomed Eng 2022; 50:1444-1451. [PMID: 36097091 DOI: 10.1007/s10439-022-03063-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/10/2022] [Indexed: 11/01/2022]
Abstract
Shoulder-to-helmet (STH) impacts have been shown to cause approximately twenty percent of concussions in football yet little research has investigated shoulder pad design and STH impacts. This study aimed to characterize STH impacts and identify the effect of shoulder pad design on the struck head kinematics. Additional padding was added to a shoulder pad, and was then compared to an unmodified control shoulder pad. Participants performed a series of tests where they struck a helmeted Hybrid III dummy with both shoulder pad variations to compare struck head linear and rotational kinematics. The study found the modified shoulder pad reduced peak linear acceleration by 31% (Δµ = - 9.13 g's (- ∞, - 7.25), (p = 4.10e-08)), rotational acceleration by 28% (Δµ = - 565 rad s-2(- ∞, - 435), (p = 2.10e-07)), peak rotational velocity by 10% (Δµ = - 2.42 rad s-1 (- ∞, - 1.54), (p = 6.9e-05)), and increased impact duration by 40% (Δµ = 9.96 ms (8.06, ∞), (p = 1.142e-08)). Impact response corridors were developed for both shoulder pad conditions and can be used to establish a controlled lab test setup that replicates STH impacts. Our findings suggest that shoulder pads have the potential to reduce head injury in football and warrant further research.
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Affiliation(s)
- Zachary Wusk
- Biomedical Engineering and Mechanics, Virginia Tech, 325 Stanger Street, Blacksburg, VA, 24061, USA
| | - Steve Rowson
- Biomedical Engineering and Mechanics, Virginia Tech, 325 Stanger Street, Blacksburg, VA, 24061, USA.
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12
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Seifert J, Shah AS, Harezlak J, Rowson S, Mihalik JP, Riggen L, Duma S, Brooks A, Cameron KL, Giza CC, Goldman J, Guskiewicz KM, Houston MN, Jackson JC, McGinty G, Pasquina P, Broglio SP, McAllister TW, McCrea MA, Stemper BD. Time Delta Head Impact Frequency: An Analysis on Head Impact Exposure in the Lead Up to a Concussion: Findings from the NCAA-DOD Care Consortium. Ann Biomed Eng 2022; 50:1473-1487. [PMID: 35933459 PMCID: PMC9652163 DOI: 10.1007/s10439-022-03032-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 07/18/2022] [Indexed: 11/30/2022]
Abstract
Sport-related concussions can result from a single high magnitude impact that generates concussive symptoms, repeated subconcussive head impacts aggregating to generate concussive symptoms, or a combined effect from the two mechanisms. The array of symptoms produced by these mechanisms may be clinically interpreted as a sport-related concussion. It was hypothesized that head impact exposure resulting in concussion is influenced by severity, total number, and frequency of subconcussive head impacts. The influence of total number and magnitude of impacts was previously explored, but frequency was investigated to a lesser degree. In this analysis, head impact frequency was investigated over a new metric called ‘time delta’, the time difference from the first recorded head impact of the day until the concussive impact. Four exposure metrics were analyzed over the time delta to determine whether frequency of head impact exposure was greater for athletes on their concussion date relative to other dates of contact participation. Those metrics included head impact frequency, head impact accrual rate, risk weighted exposure (RWE), and RWE accrual rate. Athletes experienced an elevated median number of impacts, RWE, and RWE accrual rate over the time delta on their concussion date compared to non-injury sessions. This finding suggests elevated frequency of head impact exposure on the concussion date compared to other dates that may precipitate the onset of concussion.
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Affiliation(s)
- Jack Seifert
- Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA.,Neuroscience Research Labs, Clement J. Zablocki Veterans Affairs Medical Center, Research 151, 5000 W. National Ave., Milwaukee, WI, 53295, USA
| | - Alok S Shah
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.,Neuroscience Research Labs, Clement J. Zablocki Veterans Affairs Medical Center, Research 151, 5000 W. National Ave., Milwaukee, WI, 53295, USA
| | - Jaroslaw Harezlak
- Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Steven Rowson
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
| | - Jason P Mihalik
- Matthew Gfeller Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Larry Riggen
- Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USA
| | - Stefan Duma
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
| | - Alison Brooks
- Department of Orthopedics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Kenneth L Cameron
- John A. Feagin Jr. Sports Medicine Fellowship, Keller Army Hospital, United States Military Academy, West Point, NY, USA
| | - Christopher C Giza
- Departments of Neurosurgery and Pediatrics, UCLA Steve Tisch BrainSPORT Program, David Geffem School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Joshua Goldman
- Departments of Neurosurgery and Pediatrics, UCLA Steve Tisch BrainSPORT Program, David Geffem School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Kevin M Guskiewicz
- Matthew Gfeller Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Megan N Houston
- John A. Feagin Jr. Sports Medicine Fellowship, Keller Army Hospital, United States Military Academy, West Point, NY, USA
| | - Jonathan C Jackson
- Department of Sports Medicine, United States Air Force Academy, Colorado Springs, CO, USA
| | - Gerald McGinty
- Department of Sports Medicine, United States Air Force Academy, Colorado Springs, CO, USA
| | - Paul Pasquina
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Steven P Broglio
- Michigan Concussion Center, University of Michigan, Ann Arbor, MI, USA
| | | | - Michael A McCrea
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.,Neuroscience Research Labs, Clement J. Zablocki Veterans Affairs Medical Center, Research 151, 5000 W. National Ave., Milwaukee, WI, 53295, USA
| | - Brian D Stemper
- Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA. .,Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA. .,Neuroscience Research Labs, Clement J. Zablocki Veterans Affairs Medical Center, Research 151, 5000 W. National Ave., Milwaukee, WI, 53295, USA.
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13
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Arbogast KB, Caccese JB, Buckley TA, McIntosh AS, Henderson K, Stemper BD, Solomon G, Broglio SP, Funk JR, Crandall JR. Consensus Head Acceleration Measurement Practices (CHAMP): Origins, Methods, Transparency and Disclosure. Ann Biomed Eng 2022; 50:1317-1345. [PMID: 35920964 PMCID: PMC9652170 DOI: 10.1007/s10439-022-03025-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/13/2022] [Indexed: 11/30/2022]
Abstract
The use of head kinematic measurement devices has recently proliferated owing to technology advances that make such measurement more feasible. In parallel, demand to understand the biomechanics of head impacts and injury in sports and the military has increased as the burden of such loading on the brain has received focused attention. As a result, the field has matured to the point of needing methodological guidelines to improve the rigor and consistency of research and reduce the risk of scientific bias. To this end, a diverse group of scientists undertook a comprehensive effort to define current best practices in head kinematic measurement, culminating in a series of manuscripts outlining consensus methodologies and companion summary statements. Summary statements were discussed, revised, and voted upon at the Consensus Head Acceleration Measurement Practices (CHAMP) Conference in March 2022. This manuscript summarizes the motivation and methods of the consensus process and introduces recommended reporting checklists to be used to increase transparency and rigor of future experimental design and publication of work in this field. The checklists provide an accessible means for researchers to apply the best practices summarized in the companion manuscripts when reporting studies utilizing head kinematic measurement in sport and military settings.
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Affiliation(s)
- Kristy B Arbogast
- Center for Injury Research and Prevention, Children's Hospital of Philadelphia, 2716 South St., PA, 19146, Philadelphia, USA. .,Department of Pediatrics, University of Pennsylvania, PA, Philadelphia, USA.
| | - Jaclyn B Caccese
- The Ohio State University Chronic Brain Injury Program, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Thomas A Buckley
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA
| | - Andrew S McIntosh
- McIntosh Consultancy and Research, Sydney, NSW, Australia.,Monash University Accident Research Centre, Monash University, Melbourne, VIC, Australia.,School of Engineering, Edith Cowan University, Perth, WA, Australia
| | | | - Brian D Stemper
- Joint Department of Biomedical Engineering, Medical College of Wisconsin & Marquette University, Milwaukee, WI, USA.,Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.,Neuroscience Research, Zablocki Veterans Affairs Medical Center, Milwaukee, WI, USA
| | - Gary Solomon
- National Football League Player Health and Safety, New York, NY, USA
| | - Steven P Broglio
- Michigan Concussion Center, University of Michigan, Ann Arbor, MI, USA
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14
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Best Practices for Conducting Physical Reconstructions of Head Impacts in Sport. Ann Biomed Eng 2022; 50:1409-1422. [PMID: 35876938 DOI: 10.1007/s10439-022-03024-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/13/2022] [Indexed: 11/01/2022]
Abstract
Physical reconstructions are a valuable methodology for quantifying head kinematics in sports impacts. By recreating the motion of human heads observed in video using instrumented test dummies in a laboratory, physical reconstructions allow for in-depth study of real-world head impacts using well-established surrogates such as the Hybrid III crash test dummy. The purpose of this paper is to review all aspects of the physical reconstruction methodology and discuss the advantages and limitations associated with different choices in case selection, study design, test surrogate, test apparatus, text matrix, instrumentation, and data processing. Physical reconstructions require significant resources to perform and are therefore typically limited to small sample sizes and a case series or case-control study design. Their accuracy may also be limited by a lack of dummy biofidelity. The accuracy, repeatability, and sensitivity of the reconstruction process can be characterized and improved by good laboratory practices and iterative testing. Because wearable sensors have their own limitations and are not available or practical for many sports, physical reconstructions will continue to provide a useful and complementary approach to measuring head acceleration in sport for the foreseeable future.
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15
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American Football Helmet Effectiveness Against a Strain-Based Concussion Mechanism. Ann Biomed Eng 2022; 50:1498-1509. [PMID: 35816264 DOI: 10.1007/s10439-022-03005-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/30/2022] [Indexed: 12/23/2022]
Abstract
Brain strain is increasingly being used in helmet design and safety performance evaluation as it is generally considered as the primary mechanism of concussion. In this study, we investigate whether different helmet designs can meaningfully alter brain strains using two commonly used metrics, peak maximum principal strain (MPS) of the whole brain and cumulative strain damage measure (CSDM). A convolutional neural network (CNN) that instantly produces detailed brain strains is first tested for accuracy for helmeted head impacts. Based on N = 144 impacts in 12 impact conditions from three random and representative helmet models, we conclude that the CNN is sufficiently accurate for helmet testing applications, for elementwise MPS (success rate of 98.6%), whole-brain peak MPS and CSDM (coefficient of determination of 0.977 and 0.980, with root mean squared error of 0.015 and 0.029, respectively). We then apply the technique to 23 football helmet models (N = 1104 impacts) to reproduce elementwise MPS. Assuming a concussion would occur when peak MPS or CSDM exceeds a threshold, we sweep their thresholds across the value ranges to evaluate the number of predicted hypothetical concussions that different helmets sustain across the impact conditions. Relative to the 12 impact conditions tested, we find that the "best" and "worst" helmets differ by an average of 22.5% in terms of predicted concussions, ranging from 0 to 42% (the latter achieved at the threshold value of 0.28 for peak MPS and 0.4 for CSDM, respectively). Such a large variation among helmets in strain-based concussion predictions demonstrate that helmet designs can still be optimized in a clinically meaningful way. The robustness and accuracy of the CNN tool also suggest its potential for routine use for helmet design and safety performance evaluation in the future. The CNN is freely available online at https://github.com/Jilab-biomechanics/CNN-brain-strains .
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16
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Head Impact Kinematics and Brain Deformation in Paired Opposing Youth Football Players. J Appl Biomech 2022; 38:136-147. [PMID: 35483702 DOI: 10.1123/jab.2021-0098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 01/31/2022] [Accepted: 03/03/2022] [Indexed: 11/18/2022]
Abstract
Head impact exposure is often quantified using peak resultant kinematics. While kinematics describes the inertial response of the brain to impact, they do not fully capture the dynamic brain response. Strain, a measure of the tissue-level response of the brain, may be a better predictor of injury. In this study, kinematic and strain metrics were compared to contact characteristics in youth football. Players on 2 opposing teams were instrumented with head impact sensors to record impact kinematics. Video was collected to identify contact scenarios involving opposing instrumented players (ie, paired contact scenarios) and code contact characteristics (eg, player role, impact location). A previously validated, high-resolution brain finite element model, the atlas-based brain model, was used to simulate head impacts and calculate strain metrics. Fifty-two paired contact scenarios (n = 105 impacts) were evaluated. Lighter players tended to have greater biomechanical metrics compared to heavier players. Impacts to the top of the helmet were associated with lower strain metrics. Overall, strain was better correlated with rotational kinematics, suggesting these metrics may be better predictors of the tissue-level brain response than linear kinematics. Understanding the effect of contact characteristics on brain strain will inform future efforts to improve sport safety.
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17
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An interdisciplinary computational model for predicting traumatic brain injury: Linking biomechanics and functional neural networks. Neuroimage 2022; 251:119002. [PMID: 35176490 DOI: 10.1016/j.neuroimage.2022.119002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 01/19/2022] [Accepted: 02/12/2022] [Indexed: 11/22/2022] Open
Abstract
The brain is a complex network consisting of neuron cell bodies in the gray matter and their axonal projections, forming the white matter tracts. These neurons are supported by an equally complex vascular network as well as glial cells. Traumatic brain injury (TBI) can lead to the disruption of the structural and functional brain networks due to disruption of both neuronal cell bodies in the gray matter as well as their projections and supporting cells. To explore how an impact can alter the function of brain networks, we integrated a finite element (FE) brain mechanics model with linked models of brain dynamics (Kuramoto oscillator) and vascular perfusion (Balloon-Windkessel) in this study. We used empirical resting-state functional magnetic resonance imaging (MRI) data to optimize the fit of our brain dynamics and perfusion models to clinical data. Results from the FE model were used to mimic injury in these optimized brain dynamics models: injury to the nodes (gray matter) led to a decrease in the nodal oscillation frequency, while damage to the edges (axonal connections/white matter) progressively decreased coupling among connected nodes. A total of 53 cases, including 33 non-injurious and 20 concussive head impacts experienced by professional American football players were simulated using this integrated model. We examined the correlation of injury outcomes with global measures of structural connectivity, neural dynamics, and functional connectivity of the brain networks when using different lesion methods. Results show that injurious head impacts cause significant alterations in global network topology regardless of lesion methods. Changes between the disrupted and healthy functional connectivity (measured by Pearson correlation) consistently correlated well with injury outcomes (AUC≥0.75), although the predictive performance is not significantly different (p>0.05) to that of traditional kinematic measures (angular acceleration). Intriguingly, our lesion model for gray matter damage predicted increases in global efficiency and clustering coefficient with increases in injury risk, while disrupting axonal connections led to lower network efficiency and clustering. When both injury mechanisms were combined into a single injury prediction model, the injury prediction performance depended on the thresholds used to determine neurodegeneration and mechanical tolerance for axonal injury. Together, these results point towards complex effects of mechanical trauma to the brain and provide a new framework for understanding brain injury at a causal mechanistic level and developing more effective diagnostic methods and therapeutic interventions.
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18
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Wu S, Zhao W, Barbat S, Ruan J, Ji S. Instantaneous Brain Strain Estimation for Automotive Head Impacts via Deep Learning. STAPP CAR CRASH JOURNAL 2021; 65:139-162. [PMID: 35512787 DOI: 10.4271/2021-22-0006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Efficient brain strain estimation is critical for routine application of a head injury model. Lately, a convolutional neural network (CNN) has been successfully developed to estimate spatially detailed brain strains instantly and accurately in contact sports. Here, we extend its application to automotive head impacts, where impact profiles are typically more complex with longer durations. Head impact kinematics (N=458) from two public databases were used to generate augmented impacts (N=2694). They were simulated using the anisotropic Worcester Head Injury Model (WHIM) V1.0, which provided baseline elementwise peak maximum principal strain (MPS). For each augmented impact, rotational velocity (vrot) and the corresponding rotational acceleration (arot) profiles were concatenated as static images to serve as CNN input. Three training strategies were evaluated: 1) "baseline", using random initial weights; 2) "transfer learning", using weight transfer from a previous CNN model trained on head impacts drawn from contact sports; and 3) "combined training", combining previous training data from contact sports (N=5661) for training. The combined training achieved the best performances. For peak MPS, the CNN achieved a coefficient of determination (R2) of 0.932 and root mean squared error (RMSE) of 0.031 for the real-world testing dataset. It also achieved a success rate of 60.5% and 94.8% for elementwise MPS, where the linear regression slope, k, and correlation coefficient, r, between estimated and simulated MPS did not deviate from 1.0 (when identical) by more than 0.1 and 0.2, respectively. Cumulative strain damage measure (CSDM) from the CNN estimation was also highly accurate compared to those from direct simulation across a range of thresholds (R2 of 0.899-0.943 with RMSE of 0.054-0.069). Finally, the CNN achieved an average k and r of 0.98±0.12 and 0.90±0.07, respectively, for six reconstructed car crash impacts drawn from two other sources independent of the training dataset. Importantly, the CNN is able to efficiently estimate elementwise MPS with sufficient accuracy while conventional kinematic injury metrics cannot. Therefore, the CNN has the potential to supersede current kinematic injury metrics that can only approximate a global peak MPS or CSDM. The CNN technique developed here may offer enhanced utility in the design and development of head protective countermeasures, including in the automotive industry. This is the first study aimed at instantly estimating spatially detailed brain strains for automotive head impacts, which employs >8.8 thousand impact simulations generated from ~1.5 years of nonstop computations on a high-performance computing platform.
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Affiliation(s)
- Shaoju Wu
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA 01605, USA
| | - Wei Zhao
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA 01605, USA
| | | | - Jesse Ruan
- Tianjin University of Science and Technology, Tianjin, 300222, China
| | - Songbai Ji
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA 01605, USA
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19
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Meliambro J, Karton C, Cournoyer J, Post A, Hoshizaki TB, Gilchrist MD. Comparison of head impact frequency and magnitude in youth tackle football and ice hockey. Comput Methods Biomech Biomed Engin 2021; 25:936-951. [PMID: 34615414 DOI: 10.1080/10255842.2021.1987420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Repetitive head impacts are a growing concern for youth and adolescent contact sport athletes as they have been linked to long term negative brain health outcomes. Of all contact sports, tackle football and ice hockey have been reported to have the highest incidence of head or brain injury however, each sporting environment is unique with distinct rules and regulations regarding contact and collisions. The purpose of this research was to measure and compare the head impact frequency and estimated magnitude of brain tissue strain, amongst youth tackle football and ice hockey players during game play. Head impact frequency was documented by video analysis of youth tackle football and ice hockey game play. Impact magnitude was determined through physical laboratory reconstructions and finite element modelling to estimate brain tissue strains. Tackle football demonstrated significantly higher impact frequency (P < 0.01) and magnitude of estimated brain tissue strains (P < 0.01) compared to ice hockey. A significantly higher number of higher strain head impacts were documented in tackle football when compared to ice hockey (P < 0.01). These differences suggest that youth football players may experience increased frequency and magnitude of estimated brain tissue strains in comparison to youth hockey.
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Affiliation(s)
- Julia Meliambro
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Clara Karton
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Janie Cournoyer
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Andrew Post
- School of Human Kinetics, University of Ottawa, Ottawa, Canada.,School of Mechanical & Materials Engineering, University College Dublin, Dublin, Ireland
| | | | - Michael D Gilchrist
- School of Mechanical & Materials Engineering, University College Dublin, Dublin, Ireland
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20
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Huang W, Shishehbor M, Guarín-Zapata N, Kirchhofer ND, Li J, Cruz L, Wang T, Bhowmick S, Stauffer D, Manimunda P, Bozhilov KN, Caldwell R, Zavattieri P, Kisailus D. A natural impact-resistant bicontinuous composite nanoparticle coating. NATURE MATERIALS 2020; 19:1236-1243. [PMID: 32807923 DOI: 10.1038/s41563-020-0768-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Nature utilizes the available resources to construct lightweight, strong and tough materials under constrained environmental conditions. The impact surface of the fast-striking dactyl club from the mantis shrimp is an example of one such composite material; the shrimp has evolved the capability to localize damage and avoid catastrophic failure from high-speed collisions during its feeding activities. Here we report that the dactyl club of mantis shrimps contains an impact-resistant coating composed of densely packed (about 88 per cent by volume) ~65-nm bicontinuous nanoparticles of hydroxyapatite integrated within an organic matrix. These mesocrystalline hydroxyapatite nanoparticles are assembled from small, highly aligned nanocrystals. Under impacts of high strain rates (around 104 s-1), particles rotate and translate, whereas the nanocrystalline networks fracture at low-angle grain boundaries, form dislocations and undergo amorphization. The interpenetrating organic network provides additional toughening, as well as substantial damping, with a loss coefficient of around 0.02. An unusual combination of stiffness and damping is therefore achieved, outperforming many engineered materials.
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Affiliation(s)
- Wei Huang
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USA
- Department of Materials Science and Engineering, University of California, Irvine, CA, USA
| | - Mehdi Shishehbor
- Lyles School of Civil Engineering, Purdue University, West Lafayette, IN, USA
| | | | | | - Jason Li
- Oxford Instruments Asylum Research, Goleta, CA, USA
| | - Luz Cruz
- Materials Science and Engineering Program, University of California, Riverside, CA, USA
| | - Taifeng Wang
- Materials Science and Engineering Program, University of California, Riverside, CA, USA
| | | | | | | | - Krassimir N Bozhilov
- Central Facility for Advanced Microscopy and Microanalysis, University of California, Riverside, CA, USA
| | - Roy Caldwell
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Pablo Zavattieri
- Lyles School of Civil Engineering, Purdue University, West Lafayette, IN, USA
| | - David Kisailus
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, USA.
- Department of Materials Science and Engineering, University of California, Irvine, CA, USA.
- Materials Science and Engineering Program, University of California, Riverside, CA, USA.
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21
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Reynier KA, Alshareef A, Sanchez EJ, Shedd DF, Walton SR, Erdman NK, Newman BT, Giudice JS, Higgins MJ, Funk JR, Broshek DK, Druzgal TJ, Resch JE, Panzer MB. The Effect of Muscle Activation on Head Kinematics During Non-injurious Head Impacts in Human Subjects. Ann Biomed Eng 2020; 48:2751-2762. [PMID: 32929556 DOI: 10.1007/s10439-020-02609-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022]
Abstract
In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact.
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Affiliation(s)
- Kristen A Reynier
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, USA
| | - Ahmed Alshareef
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, USA
| | | | - Daniel F Shedd
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, USA
| | - Samuel R Walton
- Department of Kinesiology, University of Virginia, Charlottesville, VA, USA
| | - Nicholas K Erdman
- Department of Kinesiology, University of Virginia, Charlottesville, VA, USA
| | - Benjamin T Newman
- Department of Radiology, University of Virginia, Charlottesville, VA, USA
| | - J Sebastian Giudice
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, USA
| | - Michael J Higgins
- Department of Kinesiology, University of Virginia, Charlottesville, VA, USA
| | | | - Donna K Broshek
- Neurocognitive Assessment Lab, University of Virginia, Charlottesville, VA, USA
| | - Thomas J Druzgal
- Department of Radiology, University of Virginia, Charlottesville, VA, USA
| | - Jacob E Resch
- Department of Kinesiology, University of Virginia, Charlottesville, VA, USA
| | - Matthew B Panzer
- Center for Applied Biomechanics, University of Virginia, Charlottesville, VA, USA.
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22
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Gabrieli D, Vigilante NF, Scheinfeld R, Rifkin JA, Schumm SN, Wu T, Gabler LF, Panzer MB, Meaney DF. A Multibody Model for Predicting Spatial Distribution of Human Brain Deformation Following Impact Loading. J Biomech Eng 2020; 142:091015. [PMID: 32266930 PMCID: PMC7247535 DOI: 10.1115/1.4046866] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/06/2020] [Indexed: 11/08/2022]
Abstract
With an increasing focus on long-term consequences of concussive brain injuries, there is a new emphasis on developing tools that can accurately predict the mechanical response of the brain to impact loading. Although finite element models (FEM) estimate the brain response under dynamic loading, these models are not capable of delivering rapid (∼seconds) estimates of the brain's mechanical response. In this study, we develop a multibody spring-mass-damper model that estimates the regional motion of the brain to rotational accelerations delivered either about one anatomic axis or across three orthogonal axes simultaneously. In total, we estimated the deformation across 120 locations within a 50th percentile human brain. We found the multibody model (MBM) correlated, but did not precisely predict, the computed finite element response (average relative error: 18.4 ± 13.1%). We used machine learning (ML) to combine the prediction from the MBM and the loading kinematics (peak rotational acceleration, peak rotational velocity) and significantly reduced the discrepancy between the MBM and FEM (average relative error: 9.8 ± 7.7%). Using an independent sports injury testing set, we found the hybrid ML model also correlated well with predictions from a FEM (average relative error: 16.4 ± 10.2%). Finally, we used this hybrid MBM-ML approach to predict strains appearing in different locations throughout the brain, with average relative error estimates ranging from 8.6% to 25.2% for complex, multi-axial acceleration loading. Together, these results show a rapid and reasonably accurate method for predicting the mechanical response of the brain for single and multiplanar inputs, and provide a new tool for quickly assessing the consequences of impact loading throughout the brain.
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Affiliation(s)
- David Gabrieli
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210. S. 33rd Street, Philadelphia, PA 19104
| | - Nicholas F. Vigilante
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210. S. 33rd Street, Philadelphia, PA 19104
| | - Rich Scheinfeld
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210. S. 33rd Street, Philadelphia, PA 19104
| | - Jared A. Rifkin
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210. S. 33rd Street, Philadelphia, PA 19104
| | - Samantha N. Schumm
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210. S. 33rd Street, Philadelphia, PA 19104
| | - Taotao Wu
- Department of Mechanical and Aerospace Engineering, Center for Applied Biomechanics, University of Virginia, P.O. Box 400237, Charlottesville, VA 22904
| | - Lee F. Gabler
- Department of Mechanical and Aerospace Engineering, Center for Applied Biomechanics, University of Virginia, P.O. Box 400237, Charlottesville, VA 22904
| | - Matthew B. Panzer
- Departments of Mechanical and Aerospace Engineering and Biomedical Engineering, Center for Applied Biomechanics, University of Virginia, P.O. Box 400237, Charlottesville, VA 22904
| | - David F. Meaney
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104
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23
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Tiernan S, Meagher A, O'Sullivan D, O'Keeffe E, Kelly E, Wallace E, Doherty CP, Campbell M, Liu Y, Domel AG. Concussion and the severity of head impacts in mixed martial arts. Proc Inst Mech Eng H 2020; 234:1472-1483. [PMID: 32799750 DOI: 10.1177/0954411920947850] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Concern about the consequences of head impacts in US football has motivated researchers to investigate and develop instrumentation to measure the severity of these impacts. However, the severity of head impacts in unhelmeted sports is largely unknown as miniaturised sensor technology has only recently made it possible to measure these impacts in vivo. The objective of this study was to measure the linear and angular head accelerations in impacts in mixed martial arts, and correlate these with concussive injuries. Thirteen mixed martial arts fighters were fitted with the Stanford instrumented mouthguard (MiG2.0) participated in this study. The mouthguard recorded linear acceleration and angular velocity in 6 degrees of freedom. Angular acceleration was calculated by differentiation. All events were video recorded, time stamped and reported impacts confirmed. A total of 451 verified head impacts above 10g were recorded during 19 sparring events (n = 298) and 11 competitive events (n = 153). The average resultant linear acceleration was 38.0624.3g while the average resultant angular acceleration was 256761739 rad/s2. The competitive bouts resulted in five concussions being diagnosed by a medical doctor. The average resultant acceleration (of the impact with the highest angular acceleration) in these bouts was 86.7618.7g and 756163438 rad/s2. The average maximum Head Impact Power was 20.6kW in the case of concussion and 7.15kW for the uninjured athletes. In conclusion, the study recorded novel data for sub-concussive and concussive impacts. Events that resulted in a concussion had an average maximum angular acceleration that was 24.7% higher and an average maximum Head Impact Power that was 189% higher than events where there was no injury. The findings are significant in understanding the human tolerance to short-duration, high linear and angular accelerations.
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Affiliation(s)
| | | | - David O'Sullivan
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Eoin O'Keeffe
- Division of Sports Science, Pusan National University, Busan, Republic of Korea
| | - Eoin Kelly
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland
| | - Eugene Wallace
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland
| | - Colin P Doherty
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland.,Academic Unit of Neurology, Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Matthew Campbell
- Division of Sports Science, Pusan National University, Busan, Republic of Korea
| | - Yuzhe Liu
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - August G Domel
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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24
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Laksari K, Fanton M, Wu LC, Nguyen TH, Kurt M, Giordano C, Kelly E, O'Keeffe E, Wallace E, Doherty C, Campbell M, Tiernan S, Grant G, Ruan J, Barbat S, Camarillo DB. Multi-Directional Dynamic Model for Traumatic Brain Injury Detection. J Neurotrauma 2020; 37:982-993. [PMID: 31856650 PMCID: PMC7175617 DOI: 10.1089/neu.2018.6340] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Given the worldwide adverse impact of traumatic brain injury (TBI) on the human population, its diagnosis and prediction are of utmost importance. Historically, many studies have focused on associating head kinematics to brain injury risk. Recently, there has been a push toward using computationally expensive finite element (FE) models of the brain to create tissue deformation metrics of brain injury. Here, we develop a new brain injury metric, the brain angle metric (BAM), based on the dynamics of a 3 degree-of-freedom lumped parameter brain model. The brain model is built based on the measured natural frequencies of an FE brain model simulated with live human impact data. We show that it can be used to rapidly estimate peak brain strains experienced during head rotational accelerations that cause mild TBI. In our data set, the simplified model correlates with peak principal FE strain (R2 = 0.82). Further, coronal and axial brain model displacement correlated with fiber-oriented peak strain in the corpus callosum (R2 = 0.77). Our proposed injury metric BAM uses the maximum angle predicted by our brain model and is compared against a number of existing rotational and translational kinematic injury metrics on a data set of head kinematics from 27 clinically diagnosed injuries and 887 non-injuries. We found that BAM performed comparably to peak angular acceleration, translational acceleration, and angular velocity in classifying injury and non-injury events. Metrics that separated time traces into their directional components had improved model deviance compare with those that combined components into a single time trace magnitude. Our brain model can be used in future work to rapidly approximate the peak strain resulting from mild to moderate head impacts and to quickly assess brain injury risk.
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Affiliation(s)
- Kaveh Laksari
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona
- Department of Bioengineering, Stanford University, Stanford, California
| | - Michael Fanton
- Department of Mechanical Engineering, Stanford University, Stanford, California
| | - Lyndia C. Wu
- Department of Bioengineering, Stanford University, Stanford, California
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Taylor H. Nguyen
- Department of Bioengineering, Stanford University, Stanford, California
| | - Mehmet Kurt
- Department of Bioengineering, Stanford University, Stanford, California
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - Chiara Giordano
- Department of Bioengineering, Stanford University, Stanford, California
| | - Eoin Kelly
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland
| | - Eoin O'Keeffe
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Eugene Wallace
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland
| | - Colin Doherty
- Department of Neurology, Health Care Centre, Hospital 5, St James's Hospital, Dublin, Ireland
| | - Matthew Campbell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Stephen Tiernan
- Department of Mechanical Engineering, Technological University Dublin, Tallaght, Dublin, Ireland
| | - Gerald Grant
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | | | | | - David B. Camarillo
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona
- Department of Bioengineering, Stanford University, Stanford, California
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25
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Cox BA, Kindle BJ, Goyeneche N, Hackel JG, Andrews JR, Saper MG. Ultrasound-guided platelet-rich plasma injection for a high-grade sternocleidomastoid tear in a professional football player. CURRENT ORTHOPAEDIC PRACTICE 2019. [DOI: 10.1097/bco.0000000000000731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Fukuda T, Koike S, Miyakawa S, Fujiya H, Yamamoto Y. Magnitude and frequency of head impact among university American football players. ACTA ACUST UNITED AC 2019. [DOI: 10.7600/jpfsm.8.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Takashi Fukuda
- Faculty of Sport and Health Science, University of Tsukuba
| | - Sekiya Koike
- Faculty of Sport and Health Science, University of Tsukuba
| | | | - Hiroto Fujiya
- Department of Sports Medicine, St. Marianna University School of Medicine
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27
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Laksari K, Kurt M, Babaee H, Kleiven S, Camarillo D. Mechanistic Insights into Human Brain Impact Dynamics through Modal Analysis. PHYSICAL REVIEW LETTERS 2018; 120:138101. [PMID: 29694192 DOI: 10.1103/physrevlett.120.138101] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 10/26/2017] [Indexed: 06/08/2023]
Abstract
Although concussion is one of the greatest health challenges today, our physical understanding of the cause of injury is limited. In this Letter, we simulated football head impacts in a finite element model and extracted the most dominant modal behavior of the brain's deformation. We showed that the brain's deformation is most sensitive in low frequency regimes close to 30 Hz, and discovered that for most subconcussive head impacts, the dynamics of brain deformation is dominated by a single global mode. In this Letter, we show the existence of localized modes and multimodal behavior in the brain as a hyperviscoelastic medium. This dynamical phenomenon leads to strain concentration patterns, particularly in deep brain regions, which is consistent with reported concussion pathology.
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Affiliation(s)
- Kaveh Laksari
- Department of Bioemedical Engineering, University of Arizona, Tucson, Arizona 95719, USA
| | - Mehmet Kurt
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA
| | - Hessam Babaee
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Svein Kleiven
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Huddinge 114 28, Sweden
| | - David Camarillo
- Department of Bioengineering, Stanford University, Stanford, California 94305, USA
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28
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Ellenbogen RG, Batjer H, Cardenas J, Berger M, Bailes J, Pieroth E, Heyer R, Theodore N, Hsu W, Nabel E, Maroon J, Cantu R, Barnes R, Collins J, Putukian M, Lonser R, Solomon G, Sills A. National Football League Head, Neck and Spine Committee’s Concussion Diagnosis and Management Protocol: 2017-18 season. Br J Sports Med 2018; 52:894-902. [DOI: 10.1136/bjsports-2018-099203] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 11/04/2022]
Abstract
One of the National Football League’s (NFL) Head, Neck and Spine Committee’s principal goals is to create a ‘best practice’ protocol for concussion diagnosis and management for its players. The science related to concussion diagnosis and management continues to evolve, thus the protocol has evolved contemporaneously. The Fifth International Conference on Concussion in Sport was held in Berlin in 2016, and guidelines for sports concussion diagnosis and management were revised and refined. The NFL Head, Neck and Spine Committee has synthesised the most recent empirical evidence for sports concussion diagnosis and management including the Berlin consensus statement and tailored it to the game played in the NFL. One of the goals of the Committee is to provide a standardised, reliable, efficient and evidence-based protocol for concussion diagnosis and management that can be applied in this professional sport during practice and game day. In this article, the end-of-season version of the 2017–18 NFL Concussion Diagnosis and Management Protocol is described along with its clinical rationale. Immediate actions for concussion programme enhancement and research are reviewed. It is the Committee’s expectation that the protocol will undergo refinement and revision over time as the science and clinical practice related to concussion in sports crystallise
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29
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Abstract
My objectives are to review: 1) a brief history of sport-related concussion (SRC) and chronic traumatic encephalopathy (CTE), 2) the evolution of CTE in American professional football, 3) the data regarding SRC/CTE as they relate to depression and suicide, 4) the data on the neurocognitive effects of subconcussion/repetitive head trauma (with emphases on heading the ball in soccer and early exposure to football), 5) the evidence related to SRC and neurodegenerative diseases, 6) the published studies of CTE, 7) the NINDS neuropathological criteria for CTE, 8) public beliefs about SRC/CTE, and 9) the scientific questions regarding CTE.
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Affiliation(s)
- Gary Solomon
- a Department of Neurological Surgery, Vanderbilt Sports Concussion Center , Vanderbilt University School of Medicine , Nashville , Tennessee , USA
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30
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Abstract
OBJECTIVE Although 70% of football players in the United States are youth players (6-14 years old), most research on head impacts in football has focused on high school, collegiate, or professional populations. The objective of this study was to identify the specific activities associated with high-magnitude (acceleration > 40g) head impacts in youth football practices. METHODS A total of 34 players (mean age 9.9 ± 0.6 years) on 2 youth teams were equipped with helmet-mounted accelerometer arrays that recorded head accelerations associated with impacts in practices and games. Videos of practices and games were used to verify all head impacts and identify specific drills associated with each head impact. RESULTS A total of 6813 impacts were recorded, of which 408 had accelerations exceeding 40g (6.0%). For each type of practice drill, impact rates were computed that accounted for the length of time that teams spent on each drill. The tackling drill King of the Circle had the highest impact rate (95% CI 25.6-68.3 impacts/hr). Impact rates for tackling drills (those conducted without a blocker [95% CI 14.7-21.9 impacts/hr] and those with a blocker [95% CI 10.5-23.1 impacts/hr]) did not differ from game impact rates (95% CI 14.2-21.6 impacts/hr). Tackling drills were observed to have a greater proportion (between 40% and 50%) of impacts exceeding 60g than games (25%). The teams in this study participated in tackling or blocking drills for only 22% of their overall practice times, but these drills were responsible for 86% of all practice impacts exceeding 40g. CONCLUSIONS In youth football, high-magnitude impacts occur more often in practices than games, and some practice drills are associated with higher impact rates and accelerations than others. To mitigate high-magnitude head impact exposure in youth football, practices should be modified to decrease the time spent in drills with high impact rates, potentially eliminating a drill such as King of the Circle altogether.
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Affiliation(s)
- Eamon T Campolettano
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia
| | - Steven Rowson
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia
| | - Stefan M Duma
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia
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31
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Jadischke R, Viano DC, McCarthy J, King AI. The Effects of Helmet Weight on Hybrid III Head and Neck Responses by Comparing Unhelmeted and Helmeted Impacts. J Biomech Eng 2016; 138:2540447. [DOI: 10.1115/1.4034306] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Indexed: 11/08/2022]
Abstract
Most studies on football helmet performance focus on lowering head acceleration-related parameters to reduce concussions. This has resulted in an increase in helmet size and mass. The objective of this paper was to study the effect of helmet mass on head and upper neck responses. Two independent test series were conducted. In test series one, 90 pendulum impact tests were conducted with four different headform and helmet conditions: unhelmeted Hybrid III headform, Hybrid III headform with a football helmet shell, Hybrid III headform with helmet shell and facemask, and Hybrid III headform with the helmet and facemask with mass added to the shell (n = 90). The Hybrid III neck was used for all the conditions. For all the configurations combined, the shell only, shell and facemask, and weighted helmet conditions resulted in 36%, 43%, and 44% lower resultant head accelerations (p < 0.0001), respectively, when compared to the unhelmeted condition. Head delta-V reductions were 1.1%, 4.5%, and 4.4%, respectively. In contrast, the helmeted conditions resulted in 26%, 41%, and 49% higher resultant neck forces (p < 0.0001), respectively. The increased neck forces were dominated by neck tension. In test series two, testing was conducted with a pneumatic linear impactor (n = 178). Fourteen different helmet makes and models illustrate the same trend. The increased neck forces provide a possible explanation as to why there has not been a corresponding reduction in concussion rates despite improvements in helmets ability to reduce head accelerations.
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Affiliation(s)
- Ron Jadischke
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48201
- McCarthy Engineering Inc., Windsor, ON N9C 4E4, Canada e-mail:
| | - David C. Viano
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48201
- ProBiomechanics LLC, Bloomfield Hills, MI 48304 e-mail:
| | - Joe McCarthy
- McCarthy Engineering Inc., Windsor, ON N9C 4E4, Canada e-mail:
| | - Albert I. King
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48201 e-mail:
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32
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King DA, Hume PA, Gissane C, Clark TN. Similar head impact acceleration measured using instrumented ear patches in a junior rugby union team during matches in comparison with other sports. J Neurosurg Pediatr 2016; 18:65-72. [PMID: 26942267 DOI: 10.3171/2015.12.peds15605] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Direct impact with the head and the inertial loading of the head have been postulated as major mechanisms of head-related injuries, such as concussion. METHODS This descriptive observational study was conducted to quantify the head impact acceleration characteristics in under-9-year-old junior rugby union players in New Zealand. The impact magnitude, frequency, and location were collected with a wireless head impact sensor that was worn by 14 junior rugby players who participated in 4 matches. RESULTS A total of 721 impacts > 10g were recorded. The median (interquartile range [IQR]) number of impacts per player was 46 (IQR 37-58), resulting in 10 (IQR 4-18) impacts to the head per player per match. The median impact magnitudes recorded were 15g (IQR 12g-21g) for linear acceleration and 2296 rad/sec(2) (IQR 1352-4152 rad/sec(2)) for rotational acceleration. CONCLUSIONS There were 121 impacts (16.8%) above the rotational injury risk limit and 1 (0.1%) impact above the linear injury risk limit. The acceleration magnitude and number of head impacts in junior rugby union players were higher than those previously reported in similar age-group sports participants. The median linear acceleration for the under-9-year-old rugby players were similar to 7- to 8-year-old American football players, but lower than 9- to 12-year-old youth American football players. The median rotational accelerations measured were higher than the median and 95th percentiles in youth, high school, and collegiate American football players.
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Affiliation(s)
- Doug A King
- Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Patria A Hume
- Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Conor Gissane
- School of Sport, Health and Applied Science, St Mary's University, Twickenham, Middlesex, United Kingdom and
| | - Trevor N Clark
- Australian College of Physical Education, Faculty of Sport Performance, Sydney Olympic Park, New South Wales, Australia
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33
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Richards D, Ivarsson BJ, Scher I, Hoover R, Rodowicz K, Cripton P. Ice hockey shoulder pad design and the effect on head response during shoulder-to-head impacts. Sports Biomech 2016; 15:385-96. [DOI: 10.1080/14763141.2016.1163414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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34
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Ban VS, Madden CJ, Bailes JE, Hunt Batjer H, Lonser RR. The science and questions surrounding chronic traumatic encephalopathy. Neurosurg Focus 2016; 40:E15. [DOI: 10.3171/2016.2.focus15609] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recently, the pathobiology, causes, associated factors, incidence and prevalence, and natural history of chronic traumatic encephalopathy (CTE) have been debated. Data from retrospective case series and high-profile media reports have fueled public fear and affected the medical community's understanding of the role of sports-related traumatic brain injury (TBI) in the development of CTE. There are a number of limitations posed by the current evidence that can lead to confusion within the public and scientific community. In this paper, the authors address common questions surrounding the science of CTE and propose future research directions.
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Affiliation(s)
- Vin Shen Ban
- 1Department of Neurological Surgery, University of Texas, Southwestern Medical Center, Dallas, Texas
| | - Christopher J. Madden
- 1Department of Neurological Surgery, University of Texas, Southwestern Medical Center, Dallas, Texas
| | - Julian E. Bailes
- 2Department of Neurological Surgery, NorthShore University HealthSystem, University of Chicago Pritzker School of Medicine, Evanston, Illinois; and
| | - H. Hunt Batjer
- 1Department of Neurological Surgery, University of Texas, Southwestern Medical Center, Dallas, Texas
| | - Russell R. Lonser
- 3Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio
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35
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Wu LC, Nangia V, Bui K, Hammoor B, Kurt M, Hernandez F, Kuo C, Camarillo DB. In Vivo Evaluation of Wearable Head Impact Sensors. Ann Biomed Eng 2016; 44:1234-45. [PMID: 26289941 PMCID: PMC4761340 DOI: 10.1007/s10439-015-1423-3] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for α(mag)) and the skull cap (320% NRMS error for a(mag), 500% for α(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.
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Affiliation(s)
- Lyndia C Wu
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA
| | - Vaibhav Nangia
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Kevin Bui
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA
| | - Bradley Hammoor
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA
| | - Mehmet Kurt
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA
| | - Fidel Hernandez
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Calvin Kuo
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - David B Camarillo
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA.
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA.
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Abstract
OBJECT
Helmets are used for sports, military, and transportation to protect against impact forces and associated injuries. The common belief among end users is that the helmet protects the whole head, including the brain. However, current consensus among biomechanists and sports neurologists indicates that helmets do not provide significant protection against concussion and brain injuries. In this paper the authors present existing scientific evidence on the mechanisms underlying traumatic head and brain injuries, along with a biomechanical evaluation of 21 current and retired football helmets.
METHODS
The National Operating Committee on Standards for Athletic Equipment (NOCSAE) standard test apparatus was modified and validated for impact testing of protective headwear to include the measurement of both linear and angular kinematics. From a drop height of 2.0 m onto a flat steel anvil, each football helmet was impacted 5 times in the occipital area.
RESULTS
Skull fracture risk was determined for each of the current varsity football helmets by calculating the percentage reduction in linear acceleration relative to a 140-g skull fracture threshold. Risk of subdural hematoma was determined by calculating the percentage reduction in angular acceleration relative to the bridging vein failure threshold, computed as a function of impact duration. Ranking the helmets according to their performance under these criteria, the authors determined that the Schutt Vengeance performed the best overall.
CONCLUSIONS
The study findings demonstrated that not all football helmets provide equal or adequate protection against either focal head injuries or traumatic brain injuries. In fact, some of the most popular helmets on the field ranked among the worst. While protection is improving, none of the current or retired varsity football helmets can provide absolute protection against brain injuries, including concussions and subdural hematomas. To maximize protection against head and brain injuries for football players of all ages, the authors propose thresholds for all sports helmets based on a peak linear acceleration no greater than 90 g and a peak angular acceleration not exceeding 1700 rad/sec2.
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Affiliation(s)
- John Lloyd
- 1BRAINS, Inc., San Antonio
- 2James A. Haley VA Medical Center, Tampa
| | - Frank Conidi
- 3Florida Center for Headache and Sports Neurology, Palm Beach Gardens; and
- 4Florida State University, College of Medicine, Tallahassee, Florida
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37
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Talavage TM, Nauman EA, Leverenz LJ. The Role of Medical Imaging in the Recharacterization of Mild Traumatic Brain Injury Using Youth Sports as a Laboratory. Front Neurol 2016; 6:273. [PMID: 26834695 PMCID: PMC4717183 DOI: 10.3389/fneur.2015.00273] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/28/2015] [Indexed: 11/13/2022] Open
Abstract
The short- and long-term impact of mild traumatic brain injury (TBI) is an increasingly vital concern for both military and civilian personnel. Such injuries produce significant social and financial burdens and necessitate improved diagnostic and treatment methods. Recent integration of neuroimaging and biomechanical studies in youth collision-sport athletes has revealed that significant alterations in brain structure and function occur even in the absence of traditional clinical markers of "concussion." While task performance is maintained, athletes exposed to repetitive head accelerations exhibit structural changes to the underlying white matter, altered glial cell metabolism, aberrant vascular response, and marked changes in functional network behavior. Moreover, these changes accumulate with accrued years of exposure, suggesting a cumulative trauma mechanism that may culminate in categorization as "concussion" and long-term neurological deficits. The goal of this review is to elucidate the role of medical imaging in recharacterizing TBI, as a whole, to better identify at-risk individuals and improve the development of preventative and interventional approaches.
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Affiliation(s)
- Thomas M Talavage
- School of Electrical and Computer Engineering, Weldon School of Biomedical Engineering, Purdue University , West Lafayette, IN , USA
| | - Eric A Nauman
- Department of Basic Medical Sciences, School of Mechanical Engineering, Weldon School of Biomedical Engineering, Purdue University , West Lafayette, IN , USA
| | - Larry J Leverenz
- Department of Health and Kinesiology, Purdue University , West Lafayette, IN , USA
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38
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Teramoto M, Petron DJ, Cross CL, Willick SE. Style of Play and Rate of Concussions in the National Football League. Orthop J Sports Med 2015; 3:2325967115620365. [PMID: 26740957 PMCID: PMC4687838 DOI: 10.1177/2325967115620365] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background: The majority of studies on concussion in the National Football League (NFL) focus on testing, evaluation, and outcomes. Meanwhile, there is a paucity of research on how a team’s style of play influences the risk of concussion. Hypothesis: Style of play, such as offensive and defensive strategies, is associated with the rate of concussions in the NFL. Study Design: Descriptive epidemiology study. Methods: The current study retrospectively analyzed data from the 2012 to 2014 NFL regular seasons. Reported numbers of concussions were stratified by each team and each position and were compared based on style of play, including offensive scheme (West Coast offense, Air Coryell offense, or other offensive schemes) and defensive alignment (3-4 or 4-3), attempts statistics, per-drive statistics, and offensive and defensive productions, along with strength of schedule (SoS) and team quality measured by simple rating system (SRS). Data analyses included descriptive statistics, 1-way analysis of variance, correlation analysis, and regression analysis. Results: There were 437 documented concussions during the 2012 to 2014 NFL regular seasons, with a mean 4.6 concussions per season per team. In general, players most involved in pass plays reported more concussions. The number of concussions sustained by offensive players was significantly higher among the teams adopting the West Coast offense (mean, 3.0) than among those utilizing the Air Coryell offense (mean, 1.6; P = .006) or those with non–West Coast offenses combined (mean, 1.9; P = .004). The multiple regression analysis revealed that the West Coast offense or not, SoS, and SRS explained 25.3% of the variance in the number of concussions by offensive players. After accounting for SRS, the West Coast offense was found to be a significant predictor of the number of concussions (P = .007), while there was a tendency for SoS to be inversely associated with the number of concussions (P = .105). None of the variables for attempts statistics, per-drive statistics, and offensive production were significantly associated with the number of concussions in the regression analysis. Conclusion: In the NFL, players most involved in pass plays appear to be at increased risk for concussions. The West Coast offense may be associated with a greater risk of concussion. Furthermore, teams with easier schedules may have more players sustaining concussions.
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Affiliation(s)
- Masaru Teramoto
- Division of Physical Medicine & Rehabilitation, University of Utah, Salt Lake City, Utah, USA
| | - David J Petron
- Department of Orthopaedic Surgery, University of Utah, Salt Lake City, Utah, USA
| | - Chad L Cross
- Department of Physical & Life Sciences, Nevada State College, Henderson, Nevada, USA
| | - Stuart E Willick
- Division of Physical Medicine & Rehabilitation, University of Utah, Salt Lake City, Utah, USA
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Courtney A, Courtney M. The Complexity of Biomechanics Causing Primary Blast-Induced Traumatic Brain Injury: A Review of Potential Mechanisms. Front Neurol 2015; 6:221. [PMID: 26539158 PMCID: PMC4609847 DOI: 10.3389/fneur.2015.00221] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/05/2015] [Indexed: 11/13/2022] Open
Abstract
Primary blast-induced traumatic brain injury (bTBI) is a prevalent battlefield injury in recent conflicts, yet biomechanical mechanisms of bTBI remain unclear. Elucidating specific biomechanical mechanisms is essential to developing animal models for testing candidate therapies and for improving protective equipment. Three hypothetical mechanisms of primary bTBI have received the most attention. Because translational and rotational head accelerations are primary contributors to TBI from non-penetrating blunt force head trauma, the acceleration hypothesis suggests that blast-induced head accelerations may cause bTBI. The hypothesis of direct cranial transmission suggests that a pressure transient traverses the skull into the brain and directly injures brain tissue. The thoracic hypothesis of bTBI suggests that some combination of a pressure transient reaching the brain via the thorax and a vagally mediated reflex result in bTBI. These three mechanisms may not be mutually exclusive, and quantifying exposure thresholds (for blasts of a given duration) is essential for determining which mechanisms may be contributing for a level of blast exposure. Progress has been hindered by experimental designs, which do not effectively expose animal models to a single mechanism and by over-reliance on poorly validated computational models. The path forward should be predictive validation of computational models by quantitative confirmation with blast experiments in animal models, human cadavers, and biofidelic human surrogates over a range of relevant blast magnitudes and durations coupled with experimental designs, which isolate a single injury mechanism.
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Affiliation(s)
- Amy Courtney
- Exponent Engineering and Scientific Consulting, Philadelphia, PA, USA
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40
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Oeur RA, Karton C, Post A, Rousseau P, Hoshizaki TB, Marshall S, Brien SE, Smith A, Cusimano MD, Gilchrist MD. A comparison of head dynamic response and brain tissue stress and strain using accident reconstructions for concussion, concussion with persistent postconcussive symptoms, and subdural hematoma. J Neurosurg 2015; 123:415-22. [DOI: 10.3171/2014.10.jns14440] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
Concussions typically resolve within several days, but in a few cases the symptoms last for a month or longer and are termed persistent postconcussive symptoms (PPCS). These persisting symptoms may also be associated with more serious brain trauma similar to subdural hematoma (SDH). The objective of this study was to investigate the head dynamic and brain tissue responses of injury reconstructions resulting in concussion, PPCS, and SDH.
METHODS
Reconstruction cases were obtained from sports medicine clinics and hospitals. All subjects received a direct blow to the head resulting in symptoms. Those symptoms that resolved in 9 days or fewer were defined as concussions (n = 3). Those with symptoms lasting longer than 18 months were defined as PPCS (n = 3), and 3 patients presented with SDHs (n = 3). A Hybrid III headform was used in reconstruction to obtain linear and rotational accelerations of the head. These dynamic response data were then input into the University College Dublin Brain Trauma Model to calculate maximum principal strain and von Mises stress. A Kruskal-Wallis test followed by Tukey post hoc tests were used to compare head dynamic and brain tissue responses between injury groups. Statistical significance was set at p < 0.05.
RESULTS
A significant difference was identified for peak resultant linear and rotational acceleration between injury groups. Post hoc analyses revealed the SDH group had higher linear and rotational acceleration responses (316 g and 23,181 rad/sec2, respectively) than the concussion group (149 g and 8111 rad/sec2, respectively; p < 0.05). No significant differences were found between groups for either brain tissue measures of maximum principal strain or von Mises stress.
CONCLUSIONS
The reconstruction of accidents resulting in a concussion with transient symptoms (low severity) and SDHs revealed a positive relationship between an increase in head dynamic response and the risk for more serious brain injury. This type of relationship was not found for brain tissue stress and strain results derived by finite element analysis. Future research should be undertaken using a larger sample size to confirm these initial findings. Understanding the relationship between the head dynamic and brain tissue response and the nature of the injury provides important information for developing strategies for injury prevention.
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Affiliation(s)
| | | | - Andrew Post
- 1School of Human Kinetics, University of Ottawa
| | | | | | - Shawn Marshall
- 2Clinical Epidemiology, Ottawa Hospital Research Institute, Ottawa, Ontario
| | - Susan E. Brien
- 3Department of Neurosurgery, Centre de Santé et de Services Sociaux (CSSS) Gatineau (Hull site), Quebec, Canada
| | - Aynsley Smith
- 4Department of Orthopedics and Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota
| | - Michael D. Cusimano
- 5Injury Prevention Research Office and Division of Neurosurgery, St. Michael's Hospital, and University of Toronto, Ontario, Canada; and
| | - Michael D. Gilchrist
- 6School of Mechanical and Materials Engineering, University College Dublin, Ireland
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41
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Rousseau P, Hoshizaki TB. Defining the effective impact mass of elbow and shoulder strikes in ice hockey. Sports Biomech 2015; 14:57-67. [DOI: 10.1080/14763141.2015.1025236] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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42
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Wilcox BJ, Beckwith JG, Greenwald RM, Raukar NP, Chu JJ, McAllister TW, Flashman LA, Maerlender AC, Duhaime AC, Crisco JJ. Biomechanics of head impacts associated with diagnosed concussion in female collegiate ice hockey players. J Biomech 2015; 48:2201-4. [PMID: 25913243 DOI: 10.1016/j.jbiomech.2015.04.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/30/2015] [Accepted: 04/02/2015] [Indexed: 11/16/2022]
Abstract
Epidemiological evidence suggests that female athletes may be at a greater risk of concussion than their male counterparts. The purpose of this study was to examine the biomechanics of head impacts associated with diagnosed concussions in a cohort of female collegiate ice hockey players. Instrumented helmets were worn by 58 female ice hockey players from 2 NCAA programs over a three year period. Kinematic measures of single impacts associated with diagnosed concussion and head impact exposure on days with and without diagnosed concussion were evaluated. Nine concussions were diagnosed. Head impact exposure was greater in frequency and magnitude on days of diagnosed concussions than on days without diagnosed concussion for individual athletes. Peak linear accelerations of head impacts associated with diagnosed concussion in this study are substantially lower than those previously reported in male athletes, while peak rotational accelerations are comparable. Further research is warranted to determine the extent to which female athletes' biomechanical tolerance to concussion injuries differs from males.
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Affiliation(s)
- Bethany J Wilcox
- Bioengineering Laboratory, Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI, USA.
| | | | - Richard M Greenwald
- Simbex, Lebanon, NH, USA; Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Neha P Raukar
- Department of Emergency Medicine, The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | | | - Thomas W McAllister
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Laura A Flashman
- Department of Psychiatry, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Arthur C Maerlender
- Center for Brain Biology and Behavior, University of Nebraska - Lincoln, Lincoln, NE, USA
| | | | - Joseph J Crisco
- Bioengineering Laboratory, Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI, USA
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43
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Forbes CR, Glutting JJ, Kaminski TW. Examining Neurocognitive Function in Previously Concussed Interscholastic Female Soccer Players. APPLIED NEUROPSYCHOLOGY-CHILD 2014; 5:14-24. [PMID: 25495584 DOI: 10.1080/21622965.2014.933108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Awareness of sport-related concussions in soccer has gained recent attention in the medical community. Interestingly, purposeful heading-a unique yet strategic and inherent part of soccer-involves repeated subconcussive blows to the head. We divided 210 female interscholastic soccer players into control (CON [never concussed]) and experimental (EXP [previously concussed]) groups. We assessed neurocognitive performance using the Automated Neuropsychological Assessment Metrics computer program before and after the players' competitive season. Headers were recorded at all sanctioned matches. Data were analyzed using a series of one-way analyses of covariance and t tests. Both groups essentially played in the same number of games (EXP = 16.1 vs. CON = 16.1) and had an equal number of total headers (EXP = 24.9 vs. CON = 24.3). Additionally, headers per game were surprisingly low in both groups (1.4 in EXP vs. 1.3 in CON). Unexpectedly, there were no significant differences between the EXP and CON groups across all dependent variables measured (p > .05). This study suggests that although previously concussed players involve themselves in purposeful heading (i.e., subconcussive insults) throughout a competitive season, there appear to be no negative consequences on neuropsychological test performance or concussion-related symptoms. Additional research is needed to determine what may result during the course of a playing career.
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Affiliation(s)
- Cameron R Forbes
- a Department of Psychology , University of Delaware , Newark , Delaware
| | | | - Thomas W Kaminski
- c Department of Kinesiology & Applied Physiology, Human Performance Laboratory , University of Delaware , Newark , Delaware
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44
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Stone JL, Patel V, Bailes JE. The History of Neurosurgical Treatment of Sports Concussion. Neurosurgery 2014; 75 Suppl 4:S3-S23. [DOI: 10.1227/neu.0000000000000488] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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45
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Hoshizaki TB, Post A, Oeur RA, Brien SE. Current and Future Concepts in Helmet and Sports Injury Prevention. Neurosurgery 2014; 75 Suppl 4:S136-48. [DOI: 10.1227/neu.0000000000000496] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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46
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Helmer KG, Pasternak O, Fredman E, Preciado RI, Koerte IK, Sasaki T, Mayinger M, Johnson AM, Holmes JD, Forwell LA, Skopelja EN, Shenton ME, Echlin PS. Hockey Concussion Education Project, Part 1. Susceptibility-weighted imaging study in male and female ice hockey players over a single season. J Neurosurg 2014; 120:864-72. [PMID: 24490839 DOI: 10.3171/2013.12.jns132093] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECT Concussion, or mild traumatic brain injury (mTBI), is a commonly occurring sports-related injury, especially in contact sports such as hockey. Cerebral microbleeds (CMBs), which appear as small, hypointense lesions on T₂*-weighted images, can result from TBI. The authors use susceptibility-weighted imaging (SWI) to automatically detect small hypointensities that may be subtle signs of chronic and acute damage due to both subconcussive and concussive injury. The goal was to investigate how the burden of these hypointensities changes over time, over a playing season, and postconcussion, in comparison with subjects who did not suffer a medically observed and diagnosed concussion. METHODS Images were obtained in 45 university-level adult male and female ice hockey players before and after a single Canadian Interuniversity Sports season. In addition, 11 subjects (5 men and 6 women) underwent imaging at 72 hours, 2 weeks, and 2 months after concussion. To identify subtle changes in brain tissue and potential CMBs, nonvessel clusters of hypointensities on SWI were automatically identified, and a hypointensity burden index was calculated for all subjects at the beginning of the season (BOS), the end of the season (EOS), and at postconcussion time points (where applicable). RESULTS A statistically significant increase in the hypointensity burden, relative to the BOS, was observed for male subjects with concussions at the 2-week postconcussion time point. A smaller, nonsignificant rise in the burden for female subjects with concussions was also observed within the same time period. There were no significant changes in burden for nonconcussed subjects of either sex between the BOS and EOS time points. However, there was a statistically significant difference in the burden between male and female subjects in the nonconcussed group at both the BOS and EOS time points, with males having a higher burden. CONCLUSIONS This method extends the utility of SWI from the enhancement and detection of larger (> 5 mm) CMBs, which are often observed in more severe cases of TBI, to cases involving smaller lesions in which visual detection of injury is difficult. The hypointensity burden metric proposed here shows statistically significant changes over time in the male subjects. A smaller, nonsignificant increase in the burden metric was observed in the female subjects.
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Affiliation(s)
- Karl G Helmer
- Massachusetts General Hospital/Massachusetts Institute of Technology/Harvard Medical School/
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47
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Bailes JE, Petraglia AL, Omalu BI, Nauman E, Talavage T. Role of subconcussion in repetitive mild traumatic brain injury. J Neurosurg 2013; 119:1235-45. [PMID: 23971952 DOI: 10.3171/2013.7.jns121822] [Citation(s) in RCA: 344] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Research now suggests that head impacts commonly occur during contact sports in which visible signs or symptoms of neurological dysfunction may not develop despite those impacts having the potential for neurological injury. Recent biophysics studies utilizing helmet accelerometers have indicated that athletes at the collegiate and high school levels sustain a surprisingly high number of head impacts ranging from several hundred to well over 1000 during the course of a season. The associated cumulative impact burdens over the course of a career are equally important. Clinical studies have also identified athletes with no readily observable symptoms but who exhibit functional impairment as measured by neuropsychological testing and functional MRI. Such findings have been corroborated by diffusion tensor imaging studies demonstrating axonal injury in asymptomatic athletes at the end of a season. Recent autopsy data have shown that there are subsets of athletes in contact sports who do not have a history of known or identified concussions but nonetheless have neurodegenerative pathology consistent with chronic traumatic encephalopathy. Finally, emerging laboratory data have demonstrated significant axonal injury, blood-brain barrier permeability, and evidence of neuroinflammation, all in the absence of behavioral changes. Such data suggest that subconcussive level impacts can lead to significant neurological alterations, especially if the blows are repetitive. The authors propose “subconcussion” as a significant emerging concept requiring thorough consideration of the potential role it plays in accruing sufficient anatomical and/or physiological damage in athletes and military personnel, such that the effects of these injuries are clinically expressed either contemporaneously or later in life.
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Affiliation(s)
- Julian E. Bailes
- 1Department of Neurosurgery, NorthShore University Health System, University of Chicago Pritzker School of Medicine, Evanston, Illinois
| | - Anthony L. Petraglia
- 2Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York
| | - Bennet I. Omalu
- 3Department of Pathology, University of California, Davis, California
| | - Eric Nauman
- 4School of Mechanical Engineering
- 5Weldon School of Biomedical Engineering; and
| | - Thomas Talavage
- 5Weldon School of Biomedical Engineering; and
- 6School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana
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48
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Bartsch A, Benzel E, Miele V, Prakash V. Editorial: Leather football helmets. J Neurosurg 2013; 119:803-4. [DOI: 10.3171/2012.12.jns122174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Adam Bartsch
- Spine Research Laboratory, and
- Cleveland Traumatic Neuromechanics Consortium; and
| | - Edward Benzel
- Spine Research Laboratory, and
- Cleveland Traumatic Neuromechanics Consortium; and
- Department of Neurosurgery, Neurological Institute, Cleveland Clinic
| | - Vincent Miele
- Cleveland Traumatic Neuromechanics Consortium; and
- Department of Neurosurgery, Neurological Institute, Cleveland Clinic
- Department of Neurosurgery, West Virginia University, Morgantown, West Virginia
| | - Vikas Prakash
- Cleveland Traumatic Neuromechanics Consortium; and
- Department of Mechanical Engineering, Case Western Reserve University, Cleveland, Ohio; and
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49
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Forbes JA, Awad AJ, Zuckerman S, Carr K, Cheng JS. Association between biomechanical parameters and concussion in helmeted collisions in American football: a review of the literature. Neurosurg Focus 2013. [PMID: 23199422 DOI: 10.3171/2012.9.focus12288] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The authors' goal was to better define the relationship between biomechanical parameters of a helmeted collision and the likelihood of concussion. METHODS The English-language literature was reviewed in search of scholarly articles describing the rotational and translational accelerations observed during all monitored impact conditions that resulted in concussion at all levels of American football. RESULTS High school players who suffer concussion experience an average of 93.9g of translational acceleration (TA) and 6505.2 rad/s(2) of rotational acceleration (RA). College athletes experience an average of 118.4g of TA and 5311.6 rad/s(2) of RA. While approximately 3% of collisions are associated with TAs greater than the mean TA associated with concussion, only about 0.02% of collisions actually result in a concussion. Associated variables that determine whether a player who experiences a severe collision also experiences a concussion remain hypothetical at present. CONCLUSIONS The ability to reliably predict the incidence of concussion based purely on biomechanical data remains elusive. This study provides novel, important information that helps to quantify the relative insignificance of biomechanical parameters in prediction of concussion risk. Further research will be necessary to better define other factors that predispose to concussion.
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Affiliation(s)
- Jonathan A Forbes
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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50
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Dashnaw ML, Petraglia AL, Bailes JE. An overview of the basic science of concussion and subconcussion: where we are and where we are going. Neurosurg Focus 2013. [PMID: 23199428 DOI: 10.3171/2012.10.focus12284] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
There has been a growing interest in the diagnosis and management of mild traumatic brain injury (TBI), or concussion. Repetitive concussion and subconcussion have been linked to a spectrum of neurological sequelae, including postconcussion syndrome, chronic traumatic encephalopathy, mild cognitive impairment, and dementia pugilistica. A more common risk than chronic traumatic encephalopathy is the season-ending or career-ending effects of concussion or its mismanagement. To effectively prevent and treat the sequelae of concussion, it will be important to understand the basic processes involved. Reviewed in this paper are the forces behind the primary phase of injury in mild TBI, as well as the immediate and delayed cellular events responsible for the secondary phase of injury leading to neuronal dysfunction and possible cell death. Advanced neuroimaging sequences have recently been developed that have the potential to increase the sensitivity of standard MRI to detect both structural and functional abnormalities associated with concussion, and have provided further insight into the potential underlying pathophysiology. Also discussed are the potential long-term effects of repetitive mild TBI, particularly chronic traumatic encephalopathy. Much of the data regarding this syndrome is limited to postmortem analyses, and at present there is no animal model of chronic traumatic encephalopathy described in the literature. As this arena of TBI research continues to evolve, it will be imperative to appropriately model concussive and even subconcussive injuries in an attempt to understand, prevent, and treat the associated chronic neurodegenerative sequelae.
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Affiliation(s)
- Matthew L Dashnaw
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York 14642, USA
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