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O'Sullivan DM, Fife GP. Biomechanical head impact characteristics during sparring practice sessions in high school taekwondo athletes. J Neurosurg Pediatr 2017; 19:662-667. [PMID: 28387642 DOI: 10.3171/2017.1.peds16432] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this study was to monitor head impact magnitude and characteristics, such as impact location and frequency, at high school taekwondo sparring sessions. METHODS Eight male high school taekwondo athletes participated in this study. The head impact characteristics were recorded by X-Patch, a wireless accelerometer and gyroscope, during 6 taekwondo sparring sessions. The outcome measures were the peak linear acceleration ( g = 9.81 msec2), peak rotational acceleration, rotational velocity, and Head Injury Criterion. RESULTS A total of 689 impacts occurred over 6 sessions involving the 8 athletes. There was an average of 24 impacts per 100 minutes, and there were significant differences in the frequency of impacts among both the sessions and individual athletes. In order of frequency, the most commonly hit locations were the side (38.2%), back (35.7%), and front (23.8%) of the head. CONCLUSIONS The data indicate that there is a relatively high number of head impacts experienced by taekwondo athletes during sparring practice. According to the rotational acceleration predicting impact severity published in previous research, 17.1% of the impacts were deemed to be a moderate and 15.5% were deemed to be severe.
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Affiliation(s)
- David M O'Sullivan
- Department of Sports Science, Pusan National University, Busan, Republic of Korea; and
| | - Gabriel P Fife
- Department of Health and Human Performance, Texas State University, San Marcos, Texas
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103
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O'Connor KL, Rowson S, Duma SM, Broglio SP. Head-Impact-Measurement Devices: A Systematic Review. J Athl Train 2017; 52:206-227. [PMID: 28387553 DOI: 10.4085/1062-6050.52.2.05] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT With an estimated 3.8 million sport- and recreation-related concussions occurring annually, targeted prevention and diagnostic methods are needed. Biomechanical analysis of head impacts may provide quantitative information that can inform both prevention and diagnostic strategies. OBJECTIVE To assess available head-impact devices and their clinical utility. DATA SOURCES We performed a systematic search of the electronic database PubMed for peer-reviewed publications, using the following phrases: accelerometer and concussion, head impact telemetry, head impacts and concussion and sensor, head impacts and sensor, impact sensor and concussion, linear acceleration and concussion, rotational acceleration and concussion, and xpatch concussion. In addition to the literature review, a Google search for head impact monitor and concussion monitor yielded 15 more devices. STUDY SELECTION Included studies were performed in vivo, used commercially available devices, and focused on sport-related concussion. DATA EXTRACTION One author reviewed the title and abstract of each study for inclusion and exclusion criteria and then reviewed each full-text article to confirm inclusion criteria. Controversial articles were reviewed by all authors to reach consensus. DATA SYNTHESIS In total, 61 peer-reviewed articles involving 4 head-impact devices were included. Participants in boxing, football, ice hockey, soccer, or snow sports ranged in age from 6 to 24 years; 18% (n = 11) of the studies included female athletes. The Head Impact Telemetry System was the most widely used device (n = 53). Fourteen additional commercially available devices were presented. CONCLUSIONS Measurements collected by impact monitors provided real-time data to estimate player exposure but did not have the requisite sensitivity to concussion. Proper interpretation of previously reported head-impact kinematics across age, sport, and position may inform future research and enable staff clinicians working on the sidelines to monitor athletes. However, head-impact-monitoring systems have limited clinical utility due to error rates, designs, and low specificity in predicting concussive injury.
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Affiliation(s)
| | - Steven Rowson
- School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg
| | - Stefan M Duma
- School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg
| | - Steven P Broglio
- NeuroTrauma Research Laboratory, University of Michigan, Ann Arbor
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104
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O'Connor KL, Peeters T, Szymanski S, Broglio SP. Individual Impact Magnitude vs. Cumulative Magnitude for Estimating Concussion Odds. Ann Biomed Eng 2017; 45:1985-1992. [PMID: 28455786 DOI: 10.1007/s10439-017-1843-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/24/2017] [Indexed: 11/28/2022]
Abstract
Helmeted impact devices have allowed researchers to investigate the biomechanics of head impacts in vivo. While increased impact magnitude has been associated with greater concussion risk, a definitive concussive threshold has not been established. It is likely that concussion risk is not determined by a single impact itself, but a host of predisposing factors. These factors may include genetics, fatigue, and/or prior head impact exposure. The objective of the current paper is to investigate the association between cumulative head impact magnitude and concussion risk. It is hypothesized that increased cumulative magnitudes will be associated with greater concussion risk. This retrospective analysis included participants that were recruited from regional high-schools in Illinois and Michigan from 2007 to 2014 as part of an ongoing study on concussion biomechanics. Across seven seasons, 185 high school football athletes were instrumented with the Head Impact Telemetry system. Out of 185 athletes, 31 (17%) sustained a concussion, with two athletes sustaining two concussions over the study period, yielding 33 concussive events. The system recorded 78,204 impacts for all concussed players. Linear acceleration, rotational acceleration, and head impact telemetry severity profile (HITsp) magnitudes were summed within five timeframes: the day of injury, three days prior to injury, seven days prior to injury, 30 days prior to injury, and prior in-season exposure. Logistic regressions were modeled to explain concussive events based on the singular linear acceleration, rotational acceleration, and HITsp event along with the calculated summations over time. Linear acceleration, rotational acceleration, and HITsp all produced significant models estimating concussion (p < 0.05). The strongest estimators of a concussive impact were the linear acceleration (OR = 1.040, p < 0.05), rotational acceleration (OR = 1.001, p < 0.05), and HITsp (OR = 1.003, p < 0.05) for the singular impact rather than any of the cumulative magnitude calculations. Moreover, no cumulative count measure was significant for linear or rotational acceleration. Results from this investigation support the growing literature indicating cumulative magnitude is not related to concussion likelihood. Cumulative magnitude is a simplistic measure of the total exposure sustained by a player over a given period. However, this measure is limited as it assumes the brain is a static structure unable to undergo self-repair. Future research should consider how biological recovery between impacts may influence concussion risk.
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Affiliation(s)
- Kathryn L O'Connor
- NeuroTrauma Research Laboratory, University of Michigan School of Kinesiology, Ann Arbor, MI, USA.
| | - Thomas Peeters
- Erasmus School of Economics, Postbus 1738, 3000 DR, Rotterdam, The Netherlands
| | - Stefan Szymanski
- University of Michigan School of Kinesiology, Ann Arbor, MI, USA
| | - Steven P Broglio
- NeuroTrauma Research Laboratory, University of Michigan Injury Center, University of Michigan School of Kinesiology, Ann Arbor, MI, USA
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105
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Internal Jugular Vein Compression: A Novel Approach to Mitigate Blast Induced Hearing Injury. Otol Neurotol 2017; 38:591-598. [DOI: 10.1097/mao.0000000000001332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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106
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VIRANI SHANE, RUSSELL COLINN, BRUSCHETTA MEGANL, HUA KEVINNGOC, POTVIN BRIGITTEM, COX DAVIDN, ROBINOVITCH STEPHENN. The Effect of Shoulder Pad Design on Head Impact Severity during Checking. Med Sci Sports Exerc 2017; 49:573-580. [DOI: 10.1249/mss.0000000000001136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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107
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Gates KM, Lane ST, Varangis E, Giovanello K, Guskiewicz K. Unsupervised Classification During Time-Series Model Building. MULTIVARIATE BEHAVIORAL RESEARCH 2017; 52:129-148. [PMID: 27925768 PMCID: PMC8549846 DOI: 10.1080/00273171.2016.1256187] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Researchers who collect multivariate time-series data across individuals must decide whether to model the dynamic processes at the individual level or at the group level. A recent innovation, group iterative multiple model estimation (GIMME), offers one solution to this dichotomy by identifying group-level time-series models in a data-driven manner while also reliably recovering individual-level patterns of dynamic effects. GIMME is unique in that it does not assume homogeneity in processes across individuals in terms of the patterns or weights of temporal effects. However, it can be difficult to make inferences from the nuances in varied individual-level patterns. The present article introduces an algorithm that arrives at subgroups of individuals that have similar dynamic models. Importantly, the researcher does not need to decide the number of subgroups. The final models contain reliable group-, subgroup-, and individual-level patterns that enable generalizable inferences, subgroups of individuals with shared model features, and individual-level patterns and estimates. We show that integrating community detection into the GIMME algorithm improves upon current standards in two important ways: (1) providing reliable classification and (2) increasing the reliability in the recovery of individual-level effects. We demonstrate this method on functional MRI from a sample of former American football players.
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Affiliation(s)
| | | | - E Varangis
- a University of North Carolina , Chapel Hill
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108
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Abstract
Context: Concussive injuries are at the forefront of sports medicine research. Recently, researchers have used a variety of head- and helmet-based impact-monitoring devices to quantify impacts sustained during contact sport participation. This review provides an up-to-date collection of head accelerometer use at the youth, high school, and collegiate levels. Evidence Acquisition: PubMed was searched for articles published between 1980 and 2015 using the terms accelerometer and concussion, impact sensor and concussion, head impact telemetry system, head impact telemetry, and linear acceleration and concussion. An additional Google search was performed to capture devices without publications. Study Design: Clinical review. Level of Evidence: Level 4. Results: Twenty-four products track and/or record head impact for clinical or research use. Ten of these head impact devices have publications supporting their utility. Conclusion: Head impact measuring devices can describe athlete exposure in terms of magnitude and/or frequency, highlighting their utility within a multimodal approach for concussion assessment and diagnosis.
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Affiliation(s)
- Richelle M Williams
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,NeuroTrauma Research Laboratory, University of Michigan, Ann Arbor, Michigan
| | - Margaret Dowling
- NeuroTrauma Research Laboratory, University of Michigan, Ann Arbor, Michigan.,School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Kathryn L O'Connor
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,NeuroTrauma Research Laboratory, University of Michigan, Ann Arbor, Michigan
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109
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Nyanzu M, Siaw-Debrah F, Ni H, Xu Z, Wang H, Lin X, Zhuge Q, Huang L. Improving on Laboratory Traumatic Brain Injury Models to Achieve Better Results. Int J Med Sci 2017; 14:494-505. [PMID: 28539826 PMCID: PMC5441042 DOI: 10.7150/ijms.18075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/31/2017] [Indexed: 11/30/2022] Open
Abstract
Experimental modeling of traumatic brain injury (TBI) in animals has identified several potential means and interventions that might have beneficial applications for treating traumatic brain injury clinically. Several of these interventions have been applied and tried with humans that are at different phases of testing (completed, prematurely terminated and others in progress). The promising results achieved in the laboratory with animal models have not been replicated with human trails as expected. This review will highlight some insights and significance attained via laboratory animal modeling of TBI as well as factors that require incorporation into the experimental studies that could help in translating results from laboratory to the bedside. Major progress has been made due to laboratory studies; in explaining the mechanisms as well as pathophysiological features of brain damage after TBI. Attempts to intervene in the cascade of events occurring after TBI all rely heavily on the knowledge from basic laboratory investigations. In looking to discover treatment, this review will endeavor to sight and state some central discrepancies between laboratory models and clinical scenarios.
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Affiliation(s)
- Mark Nyanzu
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Felix Siaw-Debrah
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Haoqi Ni
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Zhu Xu
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Hua Wang
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Xiao Lin
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Qichuan Zhuge
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Lijie Huang
- Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325000, China.,Department of Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
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110
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Collins MW, Kontos AP, Okonkwo DO, Almquist J, Bailes J, Barisa M, Bazarian J, Bloom OJ, Brody D, Cantu R, Cardenas J, Clugston J, Cohen R, Echemendia R, Elbin R, Ellenbogen R, Fonseca J, Gioia G, Guskiewicz K, Heyer R, Hotz G, Iverson GL, Jordan B, Manley G, Maroon J, McAllister T, McCrea M, Mucha A, Pieroth E, Podell K, Pombo M, Shetty T, Sills A, Solomon G, Thomas DG, Valovich McLeod TC, Yates T, Zafonte R. Statements of Agreement From the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion Meeting Held in Pittsburgh, October 15-16, 2015. Neurosurgery 2016; 79:912-929. [PMID: 27741219 PMCID: PMC5119544 DOI: 10.1227/neu.0000000000001447] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Conventional management for concussion involves prescribed rest and progressive return to activity. Recent evidence challenges this notion and suggests that active approaches may be effective for some patients. Previous concussion consensus statements provide limited guidance regarding active treatment. OBJECTIVE To describe the current landscape of treatment for concussion and to provide summary agreements related to treatment to assist clinicians in the treatment of concussion. METHODS On October 14 to 16, 2015, the Targeted Evaluation and Active Management (TEAM) Approaches to Treating Concussion meeting was convened in Pittsburgh, Pennsylvania. Thirty-seven concussion experts from neuropsychology, neurology, neurosurgery, sports medicine, physical medicine and rehabilitation, physical therapy, athletic training, and research and 12 individuals representing sport, military, and public health organizations attended the meeting. The 37 experts indicated their agreement on a series of statements using an audience response system clicker device. RESULTS A total of 16 statements of agreement were supported covering (1) Summary of the Current Approach to Treating Concussion, (2) Heterogeneity and Evolving Clinical Profiles of Concussion, (3) TEAM Approach to Concussion Treatment: Specific Strategies, and (4) Future Directions: A Call to Research. Support (ie, response of agree or somewhat agree) for the statements ranged from to 97% to 100%. CONCLUSION Concussions are characterized by diverse symptoms and impairments and evolving clinical profiles; recovery varies on the basis of modifying factors, injury severity, and treatments. Active and targeted treatments may enhance recovery after concussion. Research is needed on concussion clinical profiles, biomarkers, and the effectiveness and timing of treatments. ABBREVIATIONS ARS, audience response systemCDC, Centers for Disease Control and PreventionDoD, Department of DefensemTBI, mild traumatic brain injuryNCAA, National Collegiate Athletic AssociationNFL, National Football LeagueNIH, National Institutes of HealthRCT, randomized controlled trialRTP, return to playSRC, sport- and recreation-related concussionTBI, traumatic brain injuryTEAM, Targeted Evaluation and Active Management.
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Affiliation(s)
- Michael W. Collins
- Department of Orthopaedic Surgery, UPMC Sports Medicine Concussion Program, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Anthony P. Kontos
- Department of Orthopaedic Surgery, UPMC Sports Medicine Concussion Program, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David O. Okonkwo
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jon Almquist
- Fairfax Family Practice Comprehensive Concussion Center, Fairfax, Virginia
| | - Julian Bailes
- Department of Neurosurgery, NorthShore University Health System, Chicago, Illinois
| | - Mark Barisa
- Baylor Institute for Rehabilitation, Frisco, Texas
| | - Jeffrey Bazarian
- Department of Emergency Medicine, University of Rochester, Rochester, New York
| | - O. Josh Bloom
- Carolina Sports Concussion Clinic, Cary, North Carolina
| | - David Brody
- Department of Neurology, Washington University, St. Louis, Missouri
| | - Robert Cantu
- Dr. Robert C. Cantu Concussion Center, Emerson Hospital, Boston University, Concord, Massachusetts
| | - Javier Cardenas
- Department of Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Jay Clugston
- Community Health and Family Medicine, University of Florida, Gainesville, Florida
| | - Randall Cohen
- Athletics Department, University of Arizona, Tucson, Arizona
| | - Ruben Echemendia
- Psychological and Neurobehavioral Associates, State College, Pennsylvania
| | - R.J. Elbin
- Office for Sports Concussion Research, University of Arkansas, Fayetteville, Arkansas
| | - Richard Ellenbogen
- Department of Neurological Surgery University of Washington, Seattle, Washington
| | - Janna Fonseca
- Carolina Sports Concussion Clinic, Cary, North Carolina
| | - Gerard Gioia
- Division of Neuropsychology, Children’s National Health System, Washington, District of Columbia
| | - Kevin Guskiewicz
- College of Arts and Sciences, University of North Carolina, Chapel Hill, North Carolina
| | - Robert Heyer
- Carolinas Medical Center, Charlotte, North Carolina
| | - Gillian Hotz
- Neuroscience Center, University of Miami Miller School of Medicine, Miami, Florida
| | - Grant L. Iverson
- Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Massachusetts General Hospital, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Barry Jordan
- Neurorehabilitation, Burke Rehabilitation & Research, White Plains, New York
| | - Geoffrey Manley
- Department of Neurological Surgery, University of California at San Francisco, San Francisco, California
| | - Joseph Maroon
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | | | - Michael McCrea
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Anne Mucha
- University of Pittsburgh Medical Center Centers for Rehabilitation Services, Pittsburgh, Pennsylvania
| | - Elizabeth Pieroth
- Neurological Institute, NorthShore University Health System, Chicago, Illinois
| | - Kenneth Podell
- Houston Methodist Concussion Center, Houston Methodist Hospital, Houston, Texas
| | - Matthew Pombo
- Department of Orthpoedics, Emory University Healthcare, Atlanta, Georgia
| | - Teena Shetty
- Department of Neurology, Hospital for Special Surgery, Weill Cornell Medical College, New York City, New York
| | - Allen Sills
- Department of Neurosurgery, Vanderbilt University, Vanderbilt Sports Concussion Center, Nashville, Tennessee
| | - Gary Solomon
- Department of Neurosurgery, Vanderbilt University, Vanderbilt Sports Concussion Center, Nashville, Tennessee
| | - Danny G. Thomas
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Pediatric Emergency Medicine, Children’s Hospital of Wisconsin, Wauwatosa, Wisconsin
| | | | - Tony Yates
- Pittsburgh Steelers, Pittsburgh, Pennsylvania
| | - Ross Zafonte
- Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Massachusetts General Hospital, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
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111
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Drake A, Haut Donahue TL, Stansloski M, Fox K, Wheatley BB, Donahue SW. Horn and horn core trabecular bone of bighorn sheep rams absorbs impact energy and reduces brain cavity accelerations during high impact ramming of the skull. Acta Biomater 2016; 44:41-50. [PMID: 27544811 DOI: 10.1016/j.actbio.2016.08.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 06/20/2016] [Accepted: 08/16/2016] [Indexed: 10/21/2022]
Abstract
UNLABELLED Bighorn sheep (Ovis canadensis) routinely experience violent impacts to the head as part of intraspecific fighting. Dynamic 3D finite element models of the skull and horns of a male bighorn sheep were developed to gain an understanding of the roles that the horn and bone materials and structure play in absorbing the impact that occurs during ramming. The geometry and volume mesh of the model were derived from CT scan images. The models included the horn, bony horn core, and bone of the skull. The horn core fills a portion of the hollow horn and consists of a thin cortical bone shell filled with foam-like trabecular bone. Two modified models were also created: one with the distal half of the horn length removed to assess the effects of the tapered spiral geometry of the horn, and one with the internal trabecular bone material of the horn core removed. The trabecular bone material stored three times more strain energy during impact than the horn material in the intact model. Removing half of the horn length had the effect of increasing translational accelerations in the brain cavity by 49%. Removing the trabecular bone in the horn core resulted in a 442% increase in rotational accelerations within the brain cavity. These findings support the investigation of novel bioinspired materials and designs that could be used in mitigating brain injuries and in other applications involving high-impact collisions. STATEMENT OF SIGNIFICANCE Bighorn sheep routinely experience violent impacts to the head and horns without apparent negative consequences to the brain or horns. A portion of the horn is filled with a thin cortical bone shell containing foam-like trabecular bone. We developed novel dynamic finite element models of the skull and horns of bighorn sheep to gain an understanding of the roles that the horn and bone materials play in absorbing the impact that occurs during ramming. The study revealed that both horn and bone materials and the structures made from these materials (i.e., tapered spiral horns and foam-like trabecular bone struts) are important for absorbing impact energy and reducing brain cavity accelerations.
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112
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Dambinova SA, Maroon JC, Sufrinko AM, Mullins JD, Alexandrova EV, Potapov AA. Functional, Structural, and Neurotoxicity Biomarkers in Integrative Assessment of Concussions. Front Neurol 2016; 7:172. [PMID: 27761129 PMCID: PMC5050199 DOI: 10.3389/fneur.2016.00172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/21/2016] [Indexed: 12/20/2022] Open
Abstract
Concussion is a complex, heterogeneous process affecting the brain. Accurate assessment and diagnosis and appropriate management of concussion are essential to ensure that athletes do not prematurely return to play or others to work or active military duty, risking re-injury. To date, clinical diagnosis relies primarily on evaluating subjects for functional impairment using instruments that include neurocognitive testing, subjective symptom report, and neurobehavioral assessments, such as balance and vestibular-ocular reflex testing. Structural biomarkers, defined as advanced neuroimaging techniques and biomarkers assessing neurotoxicity and immunoexcitotoxicity, may complement the use of functional biomarkers. We hypothesize that neurotoxicity AMPA, NMDA, and kainite receptor biomarkers might be utilized as a part of comprehensive approach to concussion evaluations, with the goal of increasing diagnostic accuracy and facilitating treatment planning and prognostic assessment.
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Affiliation(s)
| | - Joseph C. Maroon
- Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
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113
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Abstract
OBJECTIVE To measure neurocognitive functioning in college and professional football players after game participation. STUDY DESIGN Retrospective, cross-sectional cohort design. PARTICIPANTS Ninety-four male university and professional football players. INTERVENTION All participants completed Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) testing at baseline, and either at postconcussion (group 1) or postgame (group 2) participation. MAIN OUTCOME MEASURES Results from the 5 ImPACT composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time and Impulse Control) and Total Symptom Score. RESULTS Repeated-measures analysis of variance demonstrated a significant main effect for time (improvements) in 3 of 5 domains for the postconcussion group, but no improvements in the postgame group. The postconcussion group presented with significantly improved results on 4 of 5 ImPACT domains compared with the postgame group at the follow-up time interval. CONCLUSIONS Participation in a football game with potential cumulative head contacts did not yield increased symptoms or cognitive impairment. However, the absence of improvement in cognitive functioning in noninjured football players, which was found in those players who were returned to play after an injury, may suggest that there is a measureable impact as a result of playing football.
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114
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Rowson S, Bland ML, Campolettano ET, Press JN, Rowson B, Smith JA, Sproule DW, Tyson AM, Duma SM. Biomechanical Perspectives on Concussion in Sport. Sports Med Arthrosc Rev 2016; 24:100-7. [PMID: 27482775 PMCID: PMC4975525 DOI: 10.1097/jsa.0000000000000121] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Concussions can occur in any sport. Often, clinical and biomechanical research efforts are disconnected. This review paper analyzes current concussion issues in sports from a biomechanical perspective and is geared toward Sports Med professionals. Overarching themes of this review include the biomechanics of the brain during head impact, role of protective equipment, potential population-based differences in concussion tolerance, potential intervention strategies to reduce the incidence of injury, and common biomechanical misconceptions.
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Affiliation(s)
- Steven Rowson
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA
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115
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Miyashita T, Diakogeorgiou E, Marrie K, Danaher R. Frequency and Location of Head Impacts in Division I Men's Lacrosse Players. ACTA ACUST UNITED AC 2016. [DOI: 10.3928/19425864-20160503-01] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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116
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Warren KM, Islam MM, LeDuc PR, Steward R. 2D and 3D Mechanobiology in Human and Nonhuman Systems. ACS APPLIED MATERIALS & INTERFACES 2016; 8:21869-21882. [PMID: 27214883 DOI: 10.1021/acsami.5b12064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mechanobiology involves the investigation of mechanical forces and their effect on the development, physiology, and pathology of biological systems. The human body has garnered much attention from many groups in the field, as mechanical forces have been shown to influence almost all aspects of human life ranging from breathing to cancer metastasis. Beyond being influential in human systems, mechanical forces have also been shown to impact nonhuman systems such as algae and zebrafish. Studies of nonhuman and human systems at the cellular level have primarily been done in two-dimensional (2D) environments, but most of these systems reside in three-dimensional (3D) environments. Furthermore, outcomes obtained from 3D studies are often quite different than those from 2D studies. We present here an overview of a select group of human and nonhuman systems in 2D and 3D environments. We also highlight mechanobiological approaches and their respective implications for human and nonhuman physiology.
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Affiliation(s)
- Kristin M Warren
- Departments of Mechanical Engineering, Biomedical Engineering, Computational Biology, and Biological Sciences, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Md Mydul Islam
- Department of Mechanical and Aerospace Engineering and Burnett School of Biomedical Sciences, University of Central Florida , Orlando, Florida 32827, United States
| | - Philip R LeDuc
- Departments of Mechanical Engineering, Biomedical Engineering, Computational Biology, and Biological Sciences, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Robert Steward
- Department of Mechanical and Aerospace Engineering and Burnett School of Biomedical Sciences, University of Central Florida , Orlando, Florida 32827, United States
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A Review of Instrumented Equipment to Investigate Head Impacts in Sport. Appl Bionics Biomech 2016; 2016:7049743. [PMID: 27594780 PMCID: PMC4993933 DOI: 10.1155/2016/7049743] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/23/2016] [Indexed: 11/18/2022] Open
Abstract
Contact, collision, and combat sports have more head impacts as compared to noncontact sports; therefore, such sports are uniquely suited to the investigation of head impact biomechanics. Recent advances in technology have enabled the development of instrumented equipment, which can estimate the head impact kinematics of human subjects in vivo. Literature pertaining to head impact measurement devices was reviewed and usage, in terms of validation and field studies, of such devices was discussed. Over the past decade, instrumented equipment has recorded millions of impacts in the laboratory, on the field, in the ring, and on the ice. Instrumented equipment is not without limitations; however, in vivo head impact data is crucial to investigate head injury mechanisms and further the understanding of concussion.
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Swift NB, Hsiung BK, Kennedy EB, Tan KT. Dynamic impact testing of hedgehog spines using a dual-arm crash pendulum. J Mech Behav Biomed Mater 2016; 61:271-282. [DOI: 10.1016/j.jmbbm.2016.03.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/24/2016] [Accepted: 03/20/2016] [Indexed: 01/01/2023]
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Schmidt JD, Guskiewicz KM, Mihalik JP, Blackburn JT, Siegmund GP, Marshall SW. Head Impact Magnitude in American High School Football. Pediatrics 2016; 138:peds.2015-4231. [PMID: 27432843 DOI: 10.1542/peds.2015-4231] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects (α = 0.05). RESULTS The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P = .03); contact with another player (linear, rotational, HITsp: P < .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P < .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P < .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered.
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Affiliation(s)
- Julianne D Schmidt
- Department of Kinesiology, and Concussion Research Laboratory, University of Georgia, Athens, Georgia;
| | - Kevin M Guskiewicz
- Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, Department of Exercise and Sport Science, Injury Prevention Research Center
| | - Jason P Mihalik
- Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, Department of Exercise and Sport Science, Injury Prevention Research Center
| | - J Troy Blackburn
- Department of Exercise and Sport Science, Neuromuscular Research Laboratory, and
| | - Gunter P Siegmund
- MEA Forensic Engineers & Scientists, Richmond, British Columbia, Canada; and School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stephen W Marshall
- Injury Prevention Research Center, Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina
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Bandwidth and sample rate requirements for wearable head impact sensors. J Biomech 2016; 49:2918-2924. [PMID: 27497499 DOI: 10.1016/j.jbiomech.2016.07.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 07/02/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022]
Abstract
Wearable inertial sensors measure human head impact kinematics important to the on-going development and validation of head injury criteria. However, sensor specifications have not been scientifically justified in the context of the anticipated field impact dynamics. The objective of our study is to determine the minimum bandwidth and sample rate required to capture the impact frequency response relevant to injury. We used high-bandwidth head impact data as ground-truth measurements, and investigated the attenuation of various injury criteria at lower bandwidths. Given a 10% attenuation threshold, we determined the minimum bandwidths required to study injury criteria based on skull kinematics and brain deformation in three different model systems: helmeted cadaver (no neck), unhelmeted cadaver (no neck), and helmeted dummy impacts (with neck). We found that higher bandwidths are required for unhelmeted impacts in general and for studying strain rate injury criteria. Minimum gyroscope bandwidths of 300Hz in helmeted sports and 500Hz in unhelmeted sports are necessary to study strain rate based injury criteria. A minimum accelerometer bandwidth of 500Hz in unhelmeted sports is necessary to study most injury criteria. Current devices typically sample at 1000Hz, with gyroscope bandwidths below 200Hz, which are not always sufficient according to these requirements. With hard contact test conditions, the identified requirements may be higher than most soft contacts on the field, but should be satisfied to capture the worst contact, and often higher risk, scenarios relative to the specific sport or activity. Our findings will help establish standard guidelines for sensor choice and design in traumatic brain injury research.
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121
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Hwang S, Ma L, Kawata K, Tierney R, Jeka JJ. Vestibular Dysfunction after Subconcussive Head Impact. J Neurotrauma 2016; 34:8-15. [PMID: 26885560 DOI: 10.1089/neu.2015.4238] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Current thinking views mild head impact (i.e., subconcussion) as an underrecognized phenomenon that has the ability to cause significant current and future detrimental neurological effects. Repeated mild impacts to the head, however, often display no observable behavioral deficits based on standard clinical tests, which may lack sensitivity. The current study investigates the effects of subconcussive impacts from soccer heading with innovative measures of vestibular function and walking stability in a pre- 0-2 h, post- 24 h post-heading repeated measures design. The heading group (n = 10) executed 10 headers with soccer balls projected at a velocity of 25 mph (11.2 m/sec) over 10 min. Subjects were evaluated 24 h before, immediately after, and 24 h after soccer heading with: the modified Balance Error Scoring System (mBESS); a walking stability task with visual feedback of trunk movement; and galvanic vestibular stimulation (GVS) while standing with eyes closed on foam. A control group (n = 10) followed the same protocol with no heading. The results showed significant decrease in trunk angle, leg angle gain, and center of mass gain relative to GVS for the heading group compared with controls. Medial-lateral trunk orientation displacement and velocity during treadmill walking increased immediately after mild head impact for the heading group compared with controls. Controls showed an improvement in mBESS scores over time, indicating a learning effect, which was not observed with the heading group. These results suggest that mild head impact leads to a transient dysfunction in vestibular processing, which deters walking stability during task performance.
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Affiliation(s)
- Sungjae Hwang
- Department of Kinesiology, Temple University , Philadelphia, Pennsylvania
| | - Lei Ma
- Department of Kinesiology, Temple University , Philadelphia, Pennsylvania
| | - Keisuke Kawata
- Department of Kinesiology, Temple University , Philadelphia, Pennsylvania
| | - Ryan Tierney
- Department of Kinesiology, Temple University , Philadelphia, Pennsylvania
| | - John J Jeka
- Department of Kinesiology, Temple University , Philadelphia, Pennsylvania
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Schmidt JD, Pierce AF, Guskiewicz KM, Register-Mihalik JK, Pamukoff DN, Mihalik JP. Safe-Play Knowledge, Aggression, and Head-Impact Biomechanics in Adolescent Ice Hockey Players. J Athl Train 2016; 51:366-72. [PMID: 27111585 DOI: 10.4085/1062-6050-51.5.04] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Addressing safe-play knowledge and player aggression could potentially improve ice hockey sport safety. OBJECTIVES To compare (1) safe-play knowledge and aggression between male and female adolescent ice hockey players and (2) head-impact frequency and severity between players with high and low levels of safe-play knowledge and aggression during practices and games. DESIGN Cohort study. SETTING On field. PATIENTS OR OTHER PARTICIPANTS Forty-one male (n = 29) and female (n = 12) adolescent ice hockey players. INTERVENTION(S) Players completed the Safe Play Questionnaire (0 = less knowledge, 7 = most knowledge) and Competitive Aggressiveness and Anger Scale (12 = less aggressive, 60 = most aggressive) at midseason. Aggressive penalty minutes were recorded throughout the season. The Head Impact Telemetry System was used to capture head-impact frequency and severity (linear acceleration [g], rotational acceleration [rad/s(2)], Head Impact Technology severity profile) at practices and games. MAIN OUTCOME MEASURE(S) One-way analyses of variance were used to compare safe play knowledge and aggression between sexes. Players were categorized as having high or low safe-play knowledge and aggression using a median split. A 2 × 2 mixed-model analysis of variance was used to compare head-impact frequency, and random-intercept general linear models were used to compare head-impact severity between groups (high, low) and event types (practice, game). RESULTS Boys (5.8 of 7 total; 95% confidence interval [CI] = 5.3, 6.3) had a trend toward better safe-play knowledge compared with girls (4.9 of 7 total; 95% CI = 3.9, 5.9; F1,36 = 3.40, P = .073). Less aggressive male players sustained significantly lower head rotational accelerations during practices (1512.8 rad/s (2) , 95% CI = 1397.3, 1637.6 rad/s(2)) versus games (1754.8 rad/s (2) , 95% CI = 1623.9, 1896.2 rad/s(2)) and versus high-aggression players during practices (1773.5 rad/s (2) , 95% CI = 1607.9, 1956.3 rad/s (2) ; F1,26 = 6.04, P = .021). CONCLUSIONS Coaches and sports medicine professionals should ensure that athletes of all levels, ages, and sexes have full knowledge of safe play and should consider aggression interventions for reducing head-impact severity among aggressive players during practice.
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Affiliation(s)
- Julianne D Schmidt
- Department of Kinesiology and Concussion Research Laboratory, University of Georgia, Athens
| | - Alice F Pierce
- Carolina Family Practice and Sports Medicine - A Duke Health Clinic, Cary, NC
| | - Kevin M Guskiewicz
- Department of Exercise and Sport Science, Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, and Injury Prevention Research Center, University of North Carolina at Chapel Hill
| | - Johna K Register-Mihalik
- Department of Exercise and Sport Science, Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, and Injury Prevention Research Center, University of North Carolina at Chapel Hill
| | - Derek N Pamukoff
- Department of Kinesiology, California State University at Fullerton
| | - Jason P Mihalik
- Department of Exercise and Sport Science, Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, and Injury Prevention Research Center, University of North Carolina at Chapel Hill
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Dickson TJ, Trathen S, Waddington G, Terwiel FA, Baltis D. A human factors approach to snowsport safety: Novel research on pediatric participants' behaviors and head injury risk. APPLIED ERGONOMICS 2016; 53 Pt A:79-86. [PMID: 26674407 DOI: 10.1016/j.apergo.2015.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 08/14/2015] [Accepted: 08/16/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVE This study applied a human factors approach to snowsport resort systems to contribute to the understanding of the incidence and severity of pediatric snowsport head accelerations. BACKGROUND Previous research indicates low magnitude head accelerations are common among snowsport participants. This study adds to the knowledge of snowsport safety by measuring aspects of participants' snowsport behavior and linking this with head acceleration data. METHOD School-aged students (n = 107) wore telemetry-fitted helmets and Global Positioning System (GPS) devices during snowsport activity. Data was collected over 159 sessions (total hours 701). Head accelerations recorded by the telemetry units were compared with GPS-generated data. RESULTS This study found speeds attained normally exceed the testing rating for which helmets are designed; lower rates of head accelerations compared to earlier studies and that when head accelerations did occur they were generally below the threshold for concussions. CONCLUSION Pediatric snowsport head accelerations are rare and are generally of low magnitude. Those most at risk of a head acceleration >40 g were male snowboarders. Given the recorded speeds in first time participants, increased targeting of novice snowsport participants to encourage education about the use of protective equipment, including helmets, is warranted. Post event recall was not a good indicator of having experienced a head impact. Consideration should be given to raising the standard design speed testing for snowsport helmet protective devices to reflect actual snowsport behaviors.
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Affiliation(s)
- Tracey J Dickson
- Research Institute for Sport and Exercise, University of Canberra, University Avenue, Canberra, ACT 2601, Australia.
| | - Stephen Trathen
- Research Institute for Sport and Exercise, University of Canberra, University Avenue, Canberra, ACT 2601, Australia.
| | - Gordon Waddington
- Research Institute for Sport and Exercise, University of Canberra, University Avenue, Canberra, ACT 2601, Australia.
| | - F Anne Terwiel
- Faculty of Adventure, Culinary Arts and Tourism, Thompson Rivers University, McGill Road, Kamloops, British Columbia, V2C 5N3, Canada.
| | - Daniel Baltis
- Faculty of Health, University of Canberra, ACT 2601, Australia
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Bowman TG, Breedlove KM, Breedlove EL, Dodge TM, Nauman EA. Impact attenuation properties of new and used lacrosse helmets. J Biomech 2015; 48:3782-7. [DOI: 10.1016/j.jbiomech.2015.08.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 08/27/2015] [Accepted: 08/29/2015] [Indexed: 11/29/2022]
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125
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Clark M, Guskiewicz K. Sport-Related Traumatic Brain Injury. TRANSLATIONAL RESEARCH IN TRAUMATIC BRAIN INJURY 2015. [DOI: 10.1201/b18959-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Sundman M, Doraiswamy PM, Morey RA. Neuroimaging assessment of early and late neurobiological sequelae of traumatic brain injury: implications for CTE. Front Neurosci 2015; 9:334. [PMID: 26441507 PMCID: PMC4585087 DOI: 10.3389/fnins.2015.00334] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/04/2015] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) has been increasingly accepted as a major external risk factor for neurodegenerative morbidity and mortality. Recent evidence indicates that the resultant chronic neurobiological sequelae following head trauma may, at least in part, contribute to a pathologically distinct disease known as Chronic Traumatic Encephalopathy (CTE). The clinical manifestation of CTE is variable, but the symptoms of this progressive disease include impaired memory and cognition, affective disorders (i.e., impulsivity, aggression, depression, suicidality, etc.), and diminished motor control. Notably, mounting evidence suggests that the pathology contributing to CTE may be caused by repetitive exposure to subconcussive hits to the head, even in those with no history of a clinically evident head injury. Given the millions of athletes and military personnel with potential exposure to repetitive subconcussive insults and TBI, CTE represents an important public health issue. However, the incidence rates and pathological mechanisms are still largely unknown, primarily due to the fact that there is no in vivo diagnostic tool. The primary objective of this manuscript is to address this limitation and discuss potential neuroimaging modalities that may be capable of diagnosing CTE in vivo through the detection of tau and other known pathological features. Additionally, we will discuss the challenges of TBI research, outline the known pathology of CTE (with an emphasis on Tau), review current neuroimaging modalities to assess the potential routes for in vivo diagnosis, and discuss the future directions of CTE research.
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Affiliation(s)
- Mark Sundman
- Duke-UNC Brain Imaging and Analysis Center, Duke University Medical Center Durham, NC, USA
| | - P Murali Doraiswamy
- Department of Psychiatry, Duke University Medical Center Durham, NC, USA ; Duke Institute for Brain Sciences, Duke University Medical Center Durham, NC, USA
| | - Rajendra A Morey
- Duke-UNC Brain Imaging and Analysis Center, Duke University Medical Center Durham, NC, USA
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Tormos CJ, Abraham C, Madihally SV. Improving the stability of chitosan–gelatin-based hydrogels for cell delivery using transglutaminase and controlled release of doxycycline. Drug Deliv Transl Res 2015; 5:575-84. [DOI: 10.1007/s13346-015-0258-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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128
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MUNCE THAYNEA, DORMAN JASONC, THOMPSON PAULA, VALENTINE VERLED, BERGERON MICHAELF. Head Impact Exposure and Neurologic Function of Youth Football Players. Med Sci Sports Exerc 2015; 47:1567-76. [DOI: 10.1249/mss.0000000000000591] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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129
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Guskiewicz K, Teel E, McCrea M. Concussion: key stakeholders and multidisciplinary participation in making sports safe. Neurosurgery 2015; 75 Suppl 4:S113-8. [PMID: 25232875 DOI: 10.1227/neu.0000000000000494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
As unstructured play declines, organized sports leagues have become a highly popular form of physical activity in young people. As concussive injuries are garnering increased media attention and public awareness, there is a growing concern for athlete safety. Although athletic trainers and physicians play a large role in keeping athletes healthy and safe, this article investigates nontraditional, multidisciplinary teams that are involved in promoting athlete safety, including the role of equipment makers, coaches, referees, governing bodies of sport, lawmakers, and fans. As opposed to a focus on diagnosing or managing concussive injuries, this article seeks to promote injury prevention strategies.
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Affiliation(s)
- Kevin Guskiewicz
- *Department of Exercise and Sport Science, University of North Carolina at Chapel Hill; ‡Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center; §Human Movement Science Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; ¶Departments of Neurosurgery and Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin; ‖Clement Zablocki Milwaukee VA Medical Center, Milwaukee, Wisconsin
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Dorminy M, Hoogeveen A, Tierney RT, Higgins M, McDevitt JK, Kretzschmar J. Effect of soccer heading ball speed on S100B, sideline concussion assessments and head impact kinematics. Brain Inj 2015; 29:1158-1164. [DOI: 10.3109/02699052.2015.1035324] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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131
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132
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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: 3.9] [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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Ji S, Zhao W, Ford JC, Beckwith JG, Bolander RP, Greenwald RM, Flashman LA, Paulsen KD, McAllister TW. Group-wise evaluation and comparison of white matter fiber strain and maximum principal strain in sports-related concussion. J Neurotrauma 2015; 32:441-54. [PMID: 24735430 DOI: 10.1089/neu.2013.3268] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sports-related concussion is a major public health problem in the United States and yet its biomechanical mechanisms remain unclear. In vitro studies demonstrate axonal elongation as a potential injury mechanism; however, current response-based injury predictors (e.g., maximum principal strain, ε(ep)) typically do not incorporate axonal orientations. We investigated the significance of white matter (WM) fiber orientation in strain estimation and compared fiber strain (ε(n)) with ε(ep) for 11 athletes with a clinical diagnosis of concussion. Geometrically accurate subject-specific head models with high mesh quality were created based on the Dartmouth Head Injury Model (DHIM), which was successfully validated (performance categorized as "good" to "excellent"). For WM regions estimated to be exposed to high strains using a range of injury thresholds (0.09-0.28), substantial differences existed between ε(n) and ε(ep) in both distribution (Dice coefficient of 0.13-0.33) and extent (∼ 5-10-fold differences), especially at higher threshold levels and higher rotational acceleration magnitudes. For example, an average of 3.2% vs. 29.8% of WM was predicted above an optimal threshold of 0.18 established from an in vivo animal study using ε(n) and ε(ep), respectively, with an average Dice coefficient of 0.14. The distribution of WM regions with high ε(n) was consistent with typical heterogeneous patterns of WM disruptions in diffuse axonal injury, and the group-wise extent at the optimal threshold matched well with the percentage of WM voxels experiencing significant longitudinal changes of fractional anisotropy and mean diffusivity (3.2% and 3.44%, respectively) found from a separate independent study. These results suggest the significance of incorporating WM microstructural anisotropy in future brain injury studies.
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Affiliation(s)
- Songbai Ji
- 1 Thayer School of Engineering, Dartmouth College , Hanover, New Hampshire
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Daniel RW, Rowson S, Duma SM. Head impact exposure in youth football: middle school ages 12-14 years. J Biomech Eng 2015; 136:094501. [PMID: 24950298 DOI: 10.1115/1.4027872] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Indexed: 11/08/2022]
Abstract
The head impact exposure experienced by football players at the college and high school levels has been well documented; however, there are limited data regarding youth football despite its dramatically larger population. The objective of this study was to investigate head impact exposure in middle school football. Impacts were monitored using a commercially available accelerometer array installed inside the helmets of 17 players aged 12-14 years. A total of 4678 impacts were measured, with an average (±standard deviation) of 275 ± 190 impacts per player. The average of impact distributions for each player had a median impact of 22 ± 2 g and 954 ± 122 rad/s², and a 95th percentile impact of 54 ± 9 g and 2525 ± 450 rad/s². Similar to the head impact exposure experienced by high school and collegiate players, these data show that middle school football players experience a greater number of head impacts during games than practices. There were no significant differences between median and 95th percentile head acceleration magnitudes experienced during games and practices; however, a larger number of impacts greater than 80 g occurred during games than during practices. Impacts to the front and back of the helmet were most common. Overall, these data are similar to high school and college data that have been collected using similar methods. These data have applications toward youth football helmet design, the development of strategies designed to limit head impact exposure, and child-specific brain injury criteria.
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135
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Measurement of Hybrid III Head Impact Kinematics Using an Accelerometer and Gyroscope System in Ice Hockey Helmets. Ann Biomed Eng 2014; 43:1896-906. [DOI: 10.1007/s10439-014-1197-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
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136
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Neck Strengthening Recommendations for Concussion Risk Reduction in Youth Sport. INTERNATIONAL JOURNAL OF ATHLETIC THERAPY AND TRAINING 2014. [DOI: 10.1123/ijatt.2014-0043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mannix R, Berglass J, Berkner J, Moleus P, Qiu J, Andrews N, Gunner G, Berglass L, Jantzie LL, Robinson S, Meehan WP. Chronic gliosis and behavioral deficits in mice following repetitive mild traumatic brain injury. J Neurosurg 2014; 121:1342-50. [PMID: 25267088 DOI: 10.3171/2014.7.jns14272] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECT With the recent increasing interest in outcomes after repetitive mild traumatic brain injury (rmTBI; e.g., sports concussions), several models of rmTBI have been established. Characterizing these models in terms of behavioral and histopathological outcomes is vital to assess their clinical translatability. The purpose of this study is to provide an in-depth behavioral and histopathological phenotype of a clinically relevant model of rmTBI. METHODS The authors used a previously published weight-drop model of rmTBI (7 injuries in 9 days) in 2- to 3-month-old mice that produces cognitive deficits without persistent loss of consciousness, seizures, gross structural imaging findings, or microscopic evidence of structural brain damage. Injured and sham-injured (anesthesia only) mice were subjected to a battery of behavioral testing, including tests of balance (rotarod), spatial memory (Morris water maze), anxiety (open field plus maze), and exploratory behavior (hole-board test). After behavioral testing, brains were assessed for histopathological outcomes, including brain volume and microglial and astrocyte immunolabeling. RESULTS Compared with sham-injured mice, mice subjected to rmTBI showed increased exploratory behavior and had impaired balance and worse spatial memory that persisted up to 3 months after injury. Long-term behavioral deficits were associated with chronic increased astrocytosis and microgliosis but no volume changes. CONCLUSIONS The authors demonstrate that their rmTBI model results in a characteristic behavioral phenotype that correlates with the clinical syndrome of concussion and repetitive concussion. This model offers a platform from which to study therapeutic interventions for rmTBI.
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138
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Head impact exposure in youth football: elementary school ages 7-8 years and the effect of returning players. Clin J Sport Med 2014; 24:416-21. [PMID: 24326933 DOI: 10.1097/jsm.0000000000000055] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To provide data describing the head impact exposure of 7- to 8-year-old football players. DESIGN Head impact data were collected from 19 players over the course of 2 seasons using helmet-mounted accelerometer arrays. SETTING Data were collected from 2 youth football teams in Blacksburg, VA, spanning 2 seasons. PARTICIPANTS A total of 19 youth football players aged 7-8 years. INDEPENDENT VARIABLES Type of session (practice or game) and the player's experience. MAIN OUTCOME MEASURES Head impact frequency, acceleration magnitude, and impact location for games, practices, and the season as a whole were measured. RESULTS The average instrumented player sustained 9 ± 6 impacts per practice, 11 ± 11 impacts per game, and 161 ± 111 impacts per season. The average instrumented player had a median impact of 16 ± 2 g and 686 ± 169 rad/s and a 95th percentile impact of 38 ± 13 g and 2052 ± 664 rad/s throughout a season. Impacts of 40 g or greater tended to occur more frequently in practices than in games, and practices had a significantly higher 95th percentile impact magnitude than games (P = 0.023). Returning players had significantly more impacts than first time players (P = 0.007). CONCLUSIONS These data are a further step toward developing effective strategies to reduce the incidence of concussion in youth football and have applications toward youth-specific football helmet designs.
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139
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Conder RL, Conder AA. Heart rate variability interventions for concussion and rehabilitation. Front Psychol 2014; 5:890. [PMID: 25165461 PMCID: PMC4131496 DOI: 10.3389/fpsyg.2014.00890] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/27/2014] [Indexed: 02/01/2023] Open
Abstract
The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.
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Affiliation(s)
- Robert L. Conder
- Department of Sports Neuropsychology, Carolina Neuropsychological ServiceRaleigh, NC, USA
| | - Alanna A. Conder
- Pediatric and Sports Neuropsychology, Carolina Neuropsychological ServiceRaleigh, NC, USA
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140
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Davenport EM, Whitlow CT, Urban JE, Espeland MA, Jung Y, Rosenbaum DA, Gioia GA, Powers AK, Stitzel JD, Maldjian JA. Abnormal white matter integrity related to head impact exposure in a season of high school varsity football. J Neurotrauma 2014; 31:1617-24. [PMID: 24786802 DOI: 10.1089/neu.2013.3233] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The aim of this study was to determine whether the cumulative effects of head impacts from a season of high school football produce magnetic resonance imaging (MRI) measureable changes in the brain in the absence of clinically diagnosed concussion. Players from a local high school football team were instrumented with the Head Impact Telemetry System (HITS™) during all practices and games. All players received pre- and postseason MRI, including diffusion tensor imaging (DTI). Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) was also conducted. Total impacts and risk-weighted cumulative exposure (RWE), including linear (RWELinear), rotational (RWERotational), and combined components (RWECP), were computed from the sensor data. Fractional, linear, planar, and spherical anisotropies (FA, CL, CP, and CS, respectively), as well as mean diffusivity (MD), were used to determine total number of abnormal white matter voxels defined as 2 standard deviations above or below the group mean. Delta (post-preseason) ImPACT scores for each individual were computed and compared to the DTI measures using Spearman's rank correlation coefficient. None of the players analyzed experienced clinical concussion (N=24). Regression analysis revealed a statistically significant linear relationship between RWECP and FA. Secondary analyses demonstrated additional statistically significant linear associations between RWE (RWECP and RWELinear) and all DTI measures. There was also a strong correlation between DTI measures and change in Verbal Memory subscore of the ImPACT. We demonstrate that a single season of football can produce brain MRI changes in the absence of clinical concussion. Similar brain MRI changes have been previously associated with mild traumatic brain injury.
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Affiliation(s)
- Elizabeth M Davenport
- 1 Advanced Neuroscience Imaging Research (ANSIR) Laboratory , Wake Forest School of Medicine, Winston-Salem, North Carolina
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141
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Angoa-Pérez M, Kane MJ, Briggs DI, Herrera-Mundo N, Viano DC, Kuhn DM. Animal models of sports-related head injury: bridging the gap between pre-clinical research and clinical reality. J Neurochem 2014; 129:916-31. [PMID: 24673291 DOI: 10.1111/jnc.12690] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 12/14/2022]
Abstract
Sports-related head impact and injury has become a very highly contentious public health and medico-legal issue. Near-daily news accounts describe the travails of concussed athletes as they struggle with depression, sleep disorders, mood swings, and cognitive problems. Some of these individuals have developed chronic traumatic encephalopathy, a progressive and debilitating neurodegenerative disorder. Animal models have always been an integral part of the study of traumatic brain injury in humans but, historically, they have concentrated on acute, severe brain injuries. This review will describe a small number of new and emerging animal models of sports-related head injury that have the potential to increase our understanding of how multiple mild head impacts, starting in adolescence, can have serious psychiatric, cognitive and histopathological outcomes much later in life. Sports-related head injury (SRHI) has emerged as a significant public health issue as athletes can develop psychiatric and neurodegenerative disorders later in life. Animal models have always been an integral part of the study of human TBI but few existing methods are valid for studying SRHI. In this review, we propose criteria for effective animal models of SRHI. Movement of the head upon impact is judged to be of primary importance in leading to concussion and persistent CNS dysfunction.
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Affiliation(s)
- Mariana Angoa-Pérez
- Research & Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA; Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
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142
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Assessment, Management and Knowledge of Sport-Related Concussion: Systematic Review. Sports Med 2014; 44:449-71. [DOI: 10.1007/s40279-013-0134-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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143
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Broglio SP, Martini D, Kasper L, Eckner JT, Kutcher JS. Estimation of head impact exposure in high school football: implications for regulating contact practices. Am J Sports Med 2013; 41:2877-84. [PMID: 24001576 PMCID: PMC4351256 DOI: 10.1177/0363546513502458] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Increased attention is being placed on the role of subconcussive impacts to the head during football participation and long-term cognitive health. Some have suggested that mitigating impacts to the head can be achieved by reducing or eliminating contact football practices. The effect that this might have on the number and magnitude of impacts is unknown. PURPOSE To estimate the effect of limiting contact practices on the frequency and magnitude of head impacts through the retrospective assessment of in vivo head impact data. STUDY DESIGN Cross-sectional study; Level of evidence, 3. METHODS Data on impact magnitude and frequency were collected with the Head Impact Telemetry System during the 2009 football season among 42 varsity high school football athletes (mean age, 16.2 ± 0.6 years; mean height, 180.9 ± 7.2 cm; mean weight, 89.8 ± 20.1 kg). Head impacts were compared between player positions and session types (noncontact practice, contact practice, and game). These results were used to estimate the frequency and magnitude of head impacts when contact sessions were restricted. RESULTS The participants collectively sustained 32,510 impacts over the 15-week season. The typical athlete sustained a mean of 774 ± 502 impacts during the season, with linemen (center, guard, and offensive or defensive tackle positions) sustaining the highest number of impacts per athlete (1076 ± 541), followed by tight ends, running backs, and linebackers (779 ± 286); wide receivers, cornerbacks, and safeties (417 ± 266); and quarterbacks (356 ± 433). When viewed by session type, noncontact practices (n = 21) accounted for 1998 total impacts (2.4 ± 1.4 per athlete per session), contact practices (n = 36) accounted for 16,346 impacts (10.5 ± 7.7 per athlete per session), and games (n = 14) accounted for 14,166 impacts (24.1 ± 19.1 per athlete per session). Significantly more impacts occurred during games when compared with contact (P = .02) and noncontact practices (P < .001), and contact practices yielded significantly more impacts than noncontact practices (P = .02). Limiting contact practices to once per week would result in a 18% reduction in impacts for the duration of a season, while eliminating all contact practices would further reduce seasonal impacts by 39% across all players. Impact magnitudes were significantly highest during game sessions compared with contact and noncontact practices. CONCLUSION Our findings suggest that limiting or eliminating contact football practices may reduce the number of head impacts sustained by athletes over the course of a season, although the effect that such rule changes may have on the magnitude of head impacts during practice sessions is less clear. As such, the potential effect of reductions in contact practices on athletes' long-term cerebral health remains unknown.
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Affiliation(s)
| | | | - Luke Kasper
- University of Louisiana at Lafayette, Lafayette, Louisiana
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144
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Beckwith JG, Greenwald RM, Chu JJ, Crisco JJ, Rowson S, Duma SM, Broglio SP, McAllister TW, Guskiewicz KM, Mihalik JP, Anderson S, Schnebel B, Brolinson PG, Collins MW. Timing of concussion diagnosis is related to head impact exposure prior to injury. Med Sci Sports Exerc 2013; 45:747-54. [PMID: 23135364 DOI: 10.1249/mss.0b013e3182793067] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Concussions are commonly undiagnosed in an athletic environment because the postinjury signs and symptoms may be mild, masked by the subject, or unrecognized. This study compares measures of head impact frequency, location, and kinematic response before cases of immediate and delayed concussion diagnosis. METHODS Football players from eight collegiate and six high school teams wore instrumented helmets during play (n = 1208), of which 95 were diagnosed with concussion (105 total cases). Acceleration data recorded by the instrumented helmets were reduced to five kinematic metrics: peak linear and rotational acceleration, Gadd severity index, head injury criterion, and change in head velocity (Δv). In addition, each impact was assigned to one of four general location regions (front, back, side, and top), and the number of impacts sustained before injury was calculated over two periods (1 and 7 days). RESULTS All head kinematic measures associated with injury, except peak rotational acceleration (P = 0.284), were significantly higher for cases of immediate diagnosis than delayed diagnosis (P < 0.05). Players with delayed diagnosis sustained a significantly higher number of head impacts on the day of injury (32.9 ± 24.9, P < 0.001) and within 7 d of injury (69.7 ± 43.3, P = 0.006) than players with immediate diagnosis (16.5 ± 15.1 and 50.2 ± 43.6). Impacts associated with concussion occurred most frequently to the front of the head (46%) followed by the top (25%), side (16%), and back (13%) with the number of impacts by location independent of temporal diagnosis (χ(3) = 4.72, P = 0.19). CONCLUSIONS Concussions diagnosed immediately after an impact event are associated with the highest kinematic measures, whereas those characterized by delayed diagnosis are preceded by a higher number of impacts.
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145
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Beckwith JG, Greenwald RM, Chu JJ, Crisco JJ, Rowson S, Duma SM, Broglio SP, McAllister TW, Guskiewicz KM, Mihalik JP, Anderson S, Schnebel B, Brolinson PG, Collins MW. Head impact exposure sustained by football players on days of diagnosed concussion. Med Sci Sports Exerc 2013; 45:737-46. [PMID: 23135363 DOI: 10.1249/mss.0b013e3182792ed7] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study compares the frequency and severity of head impacts sustained by football players on days with and without diagnosed concussion and to identify the sensitivity and specificity of single-impact severity measures to diagnosed injury. METHODS One thousand two hundred eight players from eight collegiate football teams and six high school football teams wore instrumented helmets to measure head impacts during all team sessions, of which 95 players were diagnosed with concussion. Eight players sustained two injuries and one sustained three, providing 105 injury cases. Measures of head kinematics (peak linear and rotational acceleration, Gadd severity index, head injury criteria (HIC15), and change in head velocity (Δv)) and the number of head impacts sustained by individual players were compared between days with and without diagnosed concussion. Receiver operating characteristic curves were generated to evaluate the sensitivity and specificity of each kinematic measure to diagnosed concussion using only those impacts that directly preceded diagnosis. RESULTS Players sustained a higher frequency of impacts and impacts with more severe kinematic properties on days of diagnosed concussion than on days without diagnosed concussion. Forty-five injury cases were immediately diagnosed after head impact. For these cases, peak linear acceleration and HIC15 were most sensitive to immediately diagnosed concussion (area under the curve = 0.983). Peak rotational acceleration was less sensitive to diagnosed injury than all other kinematic measures (P = 0.01), which are derived from linear acceleration (peak linear, HIC15, Gadd severity index, and Δv). CONCLUSIONS Players sustained more impacts and impacts of higher severity on days of diagnosed concussion than on days without diagnosed concussion. In addition, of historical measures of impact severity, those associated with peak linear acceleration are the best predictors of immediately diagnosed concussion.
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146
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Hildenbrand KJ, Vasavada AN. Collegiate and High School Athlete Neck Strength in Neutral and Rotated Postures. J Strength Cond Res 2013; 27:3173-82. [DOI: 10.1519/jsc.0b013e31828a1fe2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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147
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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: 368] [Impact Index Per Article: 30.7] [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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148
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The Effect of Visual and Sensory Performance on Head Impact Biomechanics in College Football Players. Ann Biomed Eng 2013; 42:1-10. [DOI: 10.1007/s10439-013-0881-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
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149
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Cobb BR, Urban JE, Davenport EM, Rowson S, Duma SM, Maldjian JA, Whitlow CT, Powers AK, Stitzel JD. Head impact exposure in youth football: elementary school ages 9-12 years and the effect of practice structure. Ann Biomed Eng 2013; 41:2463-73. [PMID: 23881111 PMCID: PMC3825505 DOI: 10.1007/s10439-013-0867-6] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/08/2013] [Indexed: 11/24/2022]
Abstract
Head impact exposure in youth football has not been well-documented, despite children under the age of 14 accounting for 70% of all football players in the United States. The objective of this study was to quantify the head impact exposure of youth football players, age 9–12, for all practices and games over the course of single season. A total of 50 players (age = 11.0 ± 1.1 years) on three teams were equipped with helmet mounted accelerometer arrays, which monitored each impact players sustained during practices and games. During the season, 11,978 impacts were recorded for this age group. Players averaged 240 ± 147 impacts for the season with linear and rotational 95th percentile magnitudes of 43 ± 7 g and 2034 ± 361 rad/s2. Overall, practice and game sessions involved similar impact frequencies and magnitudes. One of the three teams however, had substantially fewer impacts per practice and lower 95th percentile magnitudes in practices due to a concerted effort to limit contact in practices. The same team also participated in fewer practices, further reducing the number of impacts each player experienced in practice. Head impact exposures in games showed no statistical difference. While the acceleration magnitudes among 9–12 year old players tended to be lower than those reported for older players, some recorded high magnitude impacts were similar to those seen at the high school and college level. Head impact exposure in youth football may be appreciably reduced by limiting contact in practices. Further research is required to assess whether such a reduction in head impact exposure will result in a reduction in concussion incidence.
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Affiliation(s)
- Bryan R Cobb
- School of Biomedical Engineering & Sciences, Virginia Tech-Wake Forest University, 440 ICTAS Building, Stanger St., Blacksburg, VA, 24061, USA
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150
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Hutchison MG, Comper P, Meeuwisse WH, Echemendia RJ. A systematic video analysis of National Hockey League (NHL) concussions, part II: how concussions occur in the NHL. Br J Sports Med 2013; 49:552-5. [DOI: 10.1136/bjsports-2013-092235] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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