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Tooby J, Till K, Gardner A, Stokes K, Tierney G, Weaving D, Rowson S, Ghajari M, Emery C, Bussey MD, Jones B. When to Pull the Trigger: Conceptual Considerations for Approximating Head Acceleration Events Using Instrumented Mouthguards. Sports Med 2024; 54:1361-1369. [PMID: 38460080 PMCID: PMC11239719 DOI: 10.1007/s40279-024-02012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2024] [Indexed: 03/11/2024]
Abstract
Head acceleration events (HAEs) are acceleration responses of the head following external short-duration collisions. The potential risk of brain injury from a single high-magnitude HAE or repeated occurrences makes them a significant concern in sport. Instrumented mouthguards (iMGs) can approximate HAEs. The distinction between sensor acceleration events, the iMG datum for approximating HAEs and HAEs themselves, which have been defined as the in vivo event, is made to highlight limitations of approximating HAEs using iMGs. This article explores the technical limitations of iMGs that constrain the approximation of HAEs and discusses important conceptual considerations for stakeholders interpreting iMG data. The approximation of HAEs by sensor acceleration events is constrained by false positives and false negatives. False positives occur when a sensor acceleration event is recorded despite no (in vivo) HAE occurring, while false negatives occur when a sensor acceleration event is not recorded after an (in vivo) HAE has occurred. Various mechanisms contribute to false positives and false negatives. Video verification and post-processing algorithms offer effective means for eradicating most false positives, but mitigation for false negatives is less comprehensive. Consequently, current iMG research is likely to underestimate HAE exposures, especially at lower magnitudes. Future research should aim to mitigate false negatives, while current iMG datasets should be interpreted with consideration for false negatives when inferring athlete HAE exposure.
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Affiliation(s)
- James Tooby
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK.
| | - Kevin Till
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Leeds Rhinos Rugby League Club, Leeds, UK
| | - Andrew Gardner
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Sydney School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
| | - Keith Stokes
- Centre for Health and Injury and Illness Prevention in Sport, University of Bath, Bath, UK
- Medical Services, Rugby Football Union, Twickenham, UK
| | - Gregory Tierney
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Sport and Exercise Sciences Research Institute, School of Sport, Ulster University, Belfast, UK
| | - Daniel Weaving
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - Steve Rowson
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
- Leeds Beckett University, Leeds, UK
| | - Mazdak Ghajari
- Dyson School of Design Engineering, Imperial College London, London, UK
| | - Carolyn Emery
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
- Departments of Pediatrics and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Melanie Dawn Bussey
- School of Physical Education Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Ben Jones
- Carnegie Applied Rugby Research (CARR) Centre, Carnegie School of Sport, Leeds Beckett University, Leeds, UK
- Division of Physiological Sciences, Department of Human Biology, Faculty of Health Sciences, University of Cape Town and Sports Science Institute of South Africa, Cape Town, South Africa
- School of Behavioural and Health Sciences, Faculty of Health Sciences, Australian Catholic University, Brisbane, QLD, Australia
- Rugby Football League, England Performance Unit, Red Hall, Leeds, UK
- Premiership Rugby, London, UK
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2
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Brooks JS, Dickey JP. Effect of Repetitive Head Impacts on Saccade Performance in Canadian University Football Players. Clin J Sport Med 2024; 34:280-287. [PMID: 38150378 PMCID: PMC11042529 DOI: 10.1097/jsm.0000000000001202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 11/07/2023] [Indexed: 12/29/2023]
Abstract
OBJECTIVE Investigate the effect of cumulative head impacts on saccade latency and errors, measured across two successive football seasons. DESIGN Participants were acquired from a sample of convenience-one Canadian university football team. Head impacts were collected during training camp, practices, eight regular season games, and four playoff games in each season. Saccade measurements were collected at five time points-before and after training camp, at midseason, after regular season, and after playoffs. SETTING Two seasons following players from a single USports football team during practices and games. PARTICIPANTS Players who completed a baseline saccade measurement and a minimum of one follow-up measurement were included in the study. A total of 127 players were monitored across two competitive seasons, including 61 players who participated in both seasons. INDEPENDENT VARIABLES Head impact measurements were collected using helmet-mounted sensors. MAIN OUTCOME MEASURES Saccade latency and number of errors were measured using high-speed video or electro-oculography. RESULTS On average, each head impact increased prosaccade latency by 5.16 × 10 -3 ms (95% confidence interval [CI], 2.26 × 10 -4 -1.00 × 10 -2 , P = 0.03) and antisaccade latency by 5.74 × 10 -3 ms (95% CI, 7.18 × 10 -4 -1.06 × 10 -2 , P = 0.02). These latency increases did not decrease between the two seasons; in fact, prosaccade latencies were 23.20 ms longer (95% CI, 19.40-27.14, P < 0.001) at the second season's baseline measurement than the first. The number of saccade errors was not affected by cumulative head impacts. CONCLUSIONS Repetitive head impacts in Canadian university football result in cumulative declines in brain function as measured by saccade performance. CLINICAL RELEVANCE Football organizations should consider implementing policies focused on reducing head impacts to improve player safety.
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Affiliation(s)
- Jeffrey S. Brooks
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
- Department of Mechanical and Materials Engineering, Faculty of Engineering, Western University, London, ON, Canada; and
| | - James P. Dickey
- School of Kinesiology, Faculty of Health Sciences, Western University, London, ON, Canada
- School of Biomedical Engineering, Western University, London, ON, Canada
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3
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Aguiar OMG, Chow TR, Chong H, Vakili O, Robinovitch SN. Associations between the circumstances and severity of head impacts in men's university ice hockey. Sci Rep 2023; 13:17402. [PMID: 37833303 PMCID: PMC10575878 DOI: 10.1038/s41598-023-43785-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Improved evidence on the most common and severe types of head impacts in ice hockey can guide efforts to preserve brain health through improvements in protective gear, rink design, player training, and rules of play. In this observational cohort study of men's university hockey, we compared video evidence on the circumstances of 234 head impacts to measures of head impact severity (peak linear accelerations and rotational velocities) from helmet-mounted sensors (GForceTracker). Videos were analyzed with a validated questionnaire, and paired with helmet sensor data. Shoulder-to-head impacts were more common than hand- or elbow-, but there were no differences in head impact severity between upper limb contact sites (p ≥ 0.2). Head-to-glass impacts were nearly four times more common, and just as severe as head-to-board impacts (p ≥ 0.4). Head impacts resulting in major penalties (versus no penalty), or visible signs of concussion (versus no signs), involved greater head rotational velocities (p = 0.038 and 0.049, respectively). Head impacts occurred most often to the side of the head, along the boards to players in their offensive zone without puck possession. Head impact severity did not differ between cases where the head was (versus was not) the primary site of contact (p ≥ 0.6). Furthermore, penalties were called in only 4% of cases where the head was the initial point of contact. Accordingly, rules that focus on primary targeting of the head, while important and in need of improved enforcement, offer a limited solution.
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Affiliation(s)
- Olivia M G Aguiar
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.
| | - Tim R Chow
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Helen Chong
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Omid Vakili
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Stephen N Robinovitch
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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4
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Miller LE, Patalak JP, Harper MG, Urban JE, Stitzel JD. Pilot Collection and Evaluation of Head Kinematics in Stock Car Racing. J Biomech Eng 2023; 145:1152062. [PMID: 36421028 DOI: 10.1115/1.4056322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022]
Abstract
The goal of this work was to collect on-track driver head kinematics using instrumented mouthpieces and characterize environmental exposure to accelerations and vibrations. Six NASCAR drivers were instrumented with custom-fit mouthpieces to collect head kinematic data. Devices were deployed at four tracks during practice and testing environments and configured to collect approximately 11 min of linear acceleration and rotational velocity data at 200 Hz. This continuous data collection, combined with film review, allowed extraction of complete laps of data. In addition to typical data processing methods, a moving-point average was calculated and subtracted from the overall signal for both linear acceleration and rotational velocity to determine the environmental component of head motion. The current analysis focuses on 42 full laps of data collected at four data collection events. The number of laps per track ranged from 2 to 23. Linear acceleration magnitudes for all 42 laps ranged from 2.46 to 7.48 g and rotational velocity ranged from 1.25 to 3.35 rad/s. After subtracting the moving average, linear acceleration ranged from 0.92 to 5.45 g and rotational velocity ranged from 0.57 to 2.05 rad/s. This study has established the feasibility of using an instrumented mouthpiece to measure head kinematics in NASCAR and presented a technique for isolating head motion due to cornering acceleration from those due to short-term perturbations experienced by the driver.
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Affiliation(s)
- Logan E Miller
- Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, NC 27157; Center for Injury Biomechanics, Wake Forest University, 575 N Patterson Avenue, Suite 530, Winston-Salem, NC 27101
| | - John P Patalak
- National Association for Stock Car Auto Racing, Incorporated, Daytona Beach, FL 32114
| | - Matthew G Harper
- National Association for Stock Car Auto Racing, Incorporated, Daytona Beach, FL 32114
| | - Jillian E Urban
- Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, NC 27157; Center for Injury Biomechanics, Wake Forest University, 575 N Patterson Avenue, Suite 530, Winston-Salem, NC 27101
| | - Joel D Stitzel
- Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, NC 27157; Center for Injury Biomechanics, Wake Forest University, 575 N Patterson Avenue, Suite 530, Winston-Salem, NC 27101
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5
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Cheng R, Bergmann J. Impact and workload are dominating on-field data monitoring techniques to track health and well-being of team-sports athletes. Physiol Meas 2022; 43. [PMID: 35235917 DOI: 10.1088/1361-6579/ac59db] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 03/01/2022] [Indexed: 11/12/2022]
Abstract
Participation in sports has become an essential part of healthy living in today's world. However, injuries can often occur during sports participation. With advancements in sensor technology and data analytics, many sports have turned to technology-aided, data-driven, on-field monitoring techniques to help prevent injuries and plan better player management. This review searched three databases, Web of Science, IEEE, and PubMed, for peer-reviewed articles on on-field data monitoring techniques that are aimed at improving the health and well-being of team-sports athletes. It was found that most on-field data monitoring methods can be categorized as either player workload tracking or physical impact monitoring. Many studies covered during this review attempted to establish correlations between captured physical and physiological data, as well as injury risk. In these studies, workloads are frequently tracked to optimize training and prevent overtraining in addition to overuse injuries, while impacts are most often tracked to detect and investigate traumatic injuries. This review found that current sports monitoring practices often suffer from a lack of standard metrics and definitions. Furthermore, existing data-analysis models are created on data that are limited in both size and diversity. These issues need to be addressed to create ecologically valid approaches in the future.
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Affiliation(s)
- Runbei Cheng
- Department of Engineering Science, University of Oxford, Thom Building, Parks Road, Oxford, OX1 3PJ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Jeroen Bergmann
- Department of Engineering Science, University of Oxford, Thom Building, Parks Road, Oxford, OX1 3PJ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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6
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Career Head Impact Exposure Profile of Canadian University Football Players. J Appl Biomech 2022; 38:47-57. [PMID: 35045388 DOI: 10.1123/jab.2020-0228] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/03/2021] [Accepted: 12/08/2021] [Indexed: 11/18/2022]
Abstract
This study quantified head impact exposures for Canadian university football players over their varsity career. Participants included 63 players from one team that participated in a minimum of 3 seasons between 2013 and 2018. A total of 127,192 head impacts were recorded from 258 practices and 65 games. The mean (SD) number of career impacts across all positions was 2023.1 (1296.4), with an average of 37.1 (20.3) impacts per game and 7.4 (4.4) impacts per practice. The number of head impacts that players experienced during their careers increased proportionally to the number of athletic exposures (P < .001, r = .57). Linebackers and defensive and offensive linemen experienced significantly more head impacts than defensive backs, quarterbacks, and wide receivers (P ≤ .014). Seniority did not significantly affect the number of head impacts a player experienced. Mean linear acceleration increased with years of seniority within defensive backs and offensive linemen (P ≤ .01). Rotational velocity increased with years of seniority within defensive backs, defensive and offensive linemen, running backs, and wide receivers (P < .05). These data characterize career metrics of head impact exposure for Canadian university football players and provide insights to reduce head impacts through rule modifications and contact regulations.
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Head Impact Exposure and Biomechanics in University Varsity Women's Soccer. Ann Biomed Eng 2022; 50:1461-1472. [PMID: 35041117 PMCID: PMC8765100 DOI: 10.1007/s10439-022-02914-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/01/2022] [Indexed: 11/17/2022]
Abstract
Soccer is a unique sport where players purposefully and voluntarily use their unprotected heads to manipulate the direction of the ball. There are limited soccer head impact exposure data to further study brain injury risks. The objective of the current study was to combine validated mouthpiece sensors with comprehensive video analysis methods to characterize head impact exposure and biomechanics in university varsity women’s soccer. Thirteen female soccer athletes were instrumented with mouthpiece sensors to record on-field head impacts during practices, scrimmages, and games. Multi-angle video was obtained and reviewed for all on-field activity to verify mouthpiece impacts and identify contact scenarios. We recorded 1307 video-identified intentional heading impacts and 1011 video-verified sensor impacts. On average, athletes experienced 1.83 impacts per athlete-exposure, with higher exposure in practices than games/scrimmages. Median and 95th percentile peak linear and peak angular accelerations were 10.0, 22.2 g, and 765, 2296 rad/s2, respectively. Long kicks, top of the head impacts and jumping headers resulted in the highest impact kinematics. Our results demonstrate the importance of investigating and monitoring head impact exposure during soccer practices, as well as the opportunity to limit high-kinematics impact exposure through heading technique training and reducing certain contact scenarios.
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8
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Jansen AE, McGrath M, Samorezov S, Johnston J, Bartsch A, Alberts J. Characterizing Head Impact Exposure in Men and Women During Boxing and Mixed Martial Arts. Orthop J Sports Med 2021; 9:23259671211059815. [PMID: 34901294 PMCID: PMC8664317 DOI: 10.1177/23259671211059815] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/24/2021] [Indexed: 11/16/2022] Open
Abstract
Background: The accumulation of subconcussive impacts has been implicated in permanent neurological impairment. A gap in understanding the relationship between head impacts and neurological function is the lack of precise characterization and quantification of forces that individuals experience during sports training and competition. Purpose: To characterize impact exposure during training and competition among male and female athletes participating in boxing and mixed martial arts (MMA) via an instrumented custom-fit Impact Monitoring Mouthguard (IMM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-three athletes (n = 4 women) were provided a custom-fit IMM. The IMM monitored impacts during sparring and competition. All training and competition sessions were videotaped. Video and IMM data were synchronized for post hoc data verification of true positives and substantiation of impact location. IMM data were collected from boxing and MMA athletes at a collaborating site. For each true-positive impact, peak linear acceleration and peak angular acceleration were calculated. Wilcoxon rank sum tests were used to evaluate potential differences in sport, activity type, and sex with respect to each outcome. Differences in impact location were assessed via Kruskal-Wallis tests. Results: IMM data were collected from 53 amateur training sessions and 6 competitions (session range, 5-20 minutes). A total of 896 head impacts (men, n = 786; women, n = 110) were identified using IMM data and video verification: 827 in practice and 69 during competition. MMA and boxers experienced a comparable number of impacts per practice session or competition. In general, MMA impacts produced significantly higher peak angular acceleration than did boxing impacts (P < .001) and were more varied in impact location on the head during competitions. In terms of sex, men experienced a greater number of impacts than women per practice session. However, there was no significant difference between men and women in terms of impact magnitude. Conclusion: Characteristic profiles of head impact exposure differed between boxing and MMA athletes; however, the impact magnitudes were not significantly different for male and female athletes.
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Affiliation(s)
- A Elizabeth Jansen
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio, USA
| | - Morgan McGrath
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio, USA
| | - Sergey Samorezov
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio, USA
| | - Joshua Johnston
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio, USA
| | | | - Jay Alberts
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, Ohio, USA.,Neurological Institute, Cleveland Clinic, Cleveland, Ohio, USA
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Wang T, Kenny R, Wu LC. Head Impact Sensor Triggering Bias Introduced by Linear Acceleration Thresholding. Ann Biomed Eng 2021; 49:3189-3199. [PMID: 34622314 DOI: 10.1007/s10439-021-02868-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/24/2021] [Indexed: 12/24/2022]
Abstract
Contact sports players frequently sustain head impacts, most of which are mild impacts exhibiting 10-30 g peak head center-of-gravity (CG) linear acceleration. Wearable head impact sensors are commonly used to measure exposure and typically detect impacts using a linear acceleration threshold. However, linear acceleration across the head can substantially vary during 6-degree-of-freedom motion, leading to triggering biases that depend on sensor location and impact condition. We conducted an analytical investigation with impact characteristics extracted from on-field American football and soccer data. We assumed typical mouthguard sensor locations and evaluated whether simulated multi-directional impacts would trigger recording based on per-axis or resultant acceleration thresholding. Across 1387 impact directions, a 10g peak CG linear acceleration impact would trigger at only 24.7% and 31.8% of directions based on a 10 g per-axis and resultant acceleration threshold, respectively. Anterior impact locations had lower trigger rates and even a 30 g impact would not trigger recording in some directions. Such triggering biases also varied by sensor location and linear-rotational head kinematics coupling. Our results show that linear acceleration-based impact triggering could lead to considerable bias in head impact exposure measurements. We propose a set of recommendations to consider for sensor manufacturers and researchers to mitigate this potential exposure measurement bias.
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Affiliation(s)
- Timothy Wang
- Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada
| | - Rebecca Kenny
- Faculty of Medicine, The University of British Columbia, 2194 Health Sciences Mall, Vancouver, BC, Canada
| | - Lyndia C Wu
- Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
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10
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Head Impact Research Using Inertial Sensors in Sport: A Systematic Review of Methods, Demographics, and Factors Contributing to Exposure. Sports Med 2021; 52:481-504. [PMID: 34677820 DOI: 10.1007/s40279-021-01574-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND The number and magnitude of head impacts have been assessed in-vivo using inertial sensors to characterise the exposure in various sports and to help understand their potential relationship to concussion. OBJECTIVES We aimed to provide a comprehensive review of the field of in-vivo sensor acceleration event research in sports via the summary of data collection and processing methods, population demographics and factors contributing to an athlete's exposure to sensor acceleration events. METHODS The systematic search resulted in 185 cohort or cross-sectional studies that recorded sensor acceleration events in-vivo during sport participation. RESULTS Approximately 5800 participants were studied in 20 sports using 18 devices that included instrumented helmets, headbands, skin patches, mouthguards and earplugs. Female and youth participants were under-represented and ambiguous results were reported for these populations. The number and magnitude of sensor acceleration events were affected by a variety of contributing factors, suggesting sport-specific analyses are needed. For collision sports, being male, being older, and playing in a game (as opposed to a practice), all contributed to being exposed to more sensor acceleration events. DISCUSSION Several issues were identified across the various sensor technologies, and efforts should focus on harmonising research methods and improving the accuracy of kinematic measurements and impact classification. While the research is more mature for high-school and collegiate male American football players, it is still in its early stages in many other sports and for female and youth populations. The information reported in the summarised work has improved our understanding of the exposure to sport-related head impacts and has enabled the development of prevention strategies, such as rule changes. CONCLUSIONS Head impact research can help improve our understanding of the acute and chronic effects of head impacts on neurological impairments and brain injury. The field is still growing in many sports, but technological improvements and standardisation of processes are needed.
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11
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Sako K, Tanaka Y, Tomita Y, Yoshida T, Ono Y, Kashiwagi K. Effect of jaw clenching on head acceleration during a predictable load impact. J Oral Rehabil 2021; 48:1327-1336. [PMID: 34499760 DOI: 10.1111/joor.13254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/17/2021] [Accepted: 09/01/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Jaw clenching is considered to reduce head acceleration while receiving a strong impact on the body during sport activities. OBJECTIVE The present study aimed to clarify the effect of jaw clenching on reduction of head acceleration during a predictable load impact to the body. METHODS Seven healthy participants were exposed to a predictable load impact with and without jaw clenching. We recorded the electromyographic activity of the masseter (MA) and digastricus (DIG) muscles, occlusal pressure and head acceleration throughout the experiment. RESULTS When participants were not instructed to clench their jaws, they naturally positioned their jaws without occlusal contact at the time of pendulum impact by co-contracting the jaw opener and closer muscles. When participants were instructed to clench their jaws, neither the activity of the jaw opener muscle nor the head acceleration differed at the time of pendulum impact when compared with when participants were not instructed to clench their jaws. CONCLUSIONS A slightly distanced jaw position (co-contracting the jaw opener and closer muscles without occlusal contact) might serve inherently safety for reduction of head acceleration during predictable body impact, while jaw clenching does not contribute to reduction of head acceleration in response to pendulum impact more than the distanced jaw position does. Notably, DIG activation to minimise the head acceleration in response to pendulum impact was similar in clenching and no clenching positions. This suggests that DIG may play a crucial role in the reduction of head acceleration, regardless of MA muscle activity.
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Affiliation(s)
- Kazuki Sako
- Department of Fixed Prosthodontics and Occlusion, Osaka Dental University, Hirakata, Japan
| | - Yuto Tanaka
- Department of Special Care Dentistry, Osaka Dental University Hospital, Osaka, Japan
| | - Yosuke Tomita
- Department of Physical Therapy, Faculty of Health Care, Takasaki University of Health and Welfare, Takasaki, Japan
| | - Tsuyoshi Yoshida
- Department of Physical Therapy, Faculty of Health Care, Takasaki University of Health and Welfare, Takasaki, Japan
| | - Yoshiaki Ono
- Department of Special Care Dentistry, Osaka Dental University Hospital, Osaka, Japan
| | - Kosuke Kashiwagi
- Department of Fixed Prosthodontics and Occlusion, Osaka Dental University, Hirakata, Japan
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12
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Fitzpatrick D, Thompson P, Kipps C, Webborn N. Head impact forces in blind football are greater in competition than training and increased cervical strength may reduce impact magnitude. Int J Inj Contr Saf Promot 2021; 28:194-200. [PMID: 33781178 DOI: 10.1080/17457300.2021.1905667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Paralympic Blind Association Football has the highest rate of injury of any Paralympic sport and head injuries are common. This study aims to quantify head impact incidence and magnitude in Blind Football, and to examine contributing factors. This Observational study based on a Blind Football Team comprising seven male athletes 28.63 years (SD 9.74, range 16-46) over 6 months. Head mounted impact sensors were used to measure the frequency and location of impacts, as well as their linear acceleration and rotational velocity. Cervical isometric strength and proprioception was measured. There were 374 impacts recorded in 212.5 athlete hours. There was a higher rate of impacts in matches than training (Incidence Risk Ratio 2.58, 95% CI 2.01-3.30). Greater cervical strength was associated with reduced linear acceleration of impacts (R2 = 0.1912, p = .020). Blind Football players are exposed to a greater number of head impacts in matches than training. Neck muscle strength may influence magnitude of head impact forces in this sport but further study is required to further investigate.
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Affiliation(s)
- Daniel Fitzpatrick
- Centre for Sport and Exercise Science and Medicine, University of Brighton, Brighton, UK.,Institute of Sport, Exercise and Health, University College London, London, UK
| | | | - Courtney Kipps
- Institute of Sport, Exercise and Health, University College London, London, UK
| | - Nick Webborn
- Centre for Sport and Exercise Science and Medicine, University of Brighton, Brighton, UK
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13
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Brooks JS, Redgrift A, Champagne AA, Dickey JP. The Hammer and the Nail: Biomechanics of Striking and Struck Canadian University Football Players. Ann Biomed Eng 2021; 49:2875-2885. [PMID: 33893576 PMCID: PMC8510945 DOI: 10.1007/s10439-021-02773-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/27/2021] [Indexed: 01/04/2023]
Abstract
This study sought to evaluate head accelerations in both players involved in a football collision. Players on two opposing Canadian university teams were equipped with helmet mounted sensors during one game per season, for two consecutive seasons. A total of 276 collisions between 58 instrumented players were identified via video and cross-referenced with sensor timestamps. Player involvement (striking and struck), impact type (block or tackle), head impact location (front, back, left and right), and play type were recorded from video footage. While struck players did not experience significantly different linear or rotational accelerations between any play types, striking players had the highest linear and rotational head accelerations during kickoff plays (p ≤ .03). Striking players also experienced greater linear and rotational head accelerations than struck players during kickoff plays (p = .001). However, struck players experienced greater linear and rotational accelerations than striking players during kick return plays (p ≤ .008). Other studies have established that the more severe the head impact, the greater risk for injury to the brain. This paper's results highlight that kickoff play rule changes, as implemented in American college football, would decrease head impact exposure of Canadian university football athletes and make the game safer.
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Affiliation(s)
- Jeffrey S. Brooks
- grid.39381.300000 0004 1936 8884School of Kinesiology, Faculty of Health Sciences, Western University, 1151 Richmond St., London, ON Canada
| | - Adam Redgrift
- grid.39381.300000 0004 1936 8884School of Kinesiology, Faculty of Health Sciences, Western University, 1151 Richmond St., London, ON Canada
| | - Allen A. Champagne
- grid.410356.50000 0004 1936 8331Centre for Neuroscience Studies, Queen’s University, Kingston, ON Canada ,grid.410356.50000 0004 1936 8331School of Medicine, Queen’s University, Kingston, ON Canada
| | - James P. Dickey
- grid.39381.300000 0004 1936 8884School of Kinesiology, Faculty of Health Sciences, Western University, 1151 Richmond St., London, ON Canada
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14
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Describing headform pose and impact location for blunt impact testing. J Biomech 2020; 109:109923. [PMID: 32807308 DOI: 10.1016/j.jbiomech.2020.109923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 06/26/2020] [Accepted: 06/26/2020] [Indexed: 11/22/2022]
Abstract
Reproduction of anthropomorphic test device (ATD) head impact test methods is a critical element needed to develop guidance and technologies that reduce the risk for brain injury in sport. However, there does not appear to be a consensus for reporting ATD pose and impact location for industry and researchers to follow. Thus, the purpose of this article is to explore the various methods used to report impact location and ATD head pose for sport-related head impact testing and provide recommendations for standardizing these descriptions. A database search and exclusion process identified 137 articles that met the review criteria. Only 4 of the 137 articles provided a description similar to the method we propose to describe ATD pose and impact location. We thus propose a method to unambiguously convey the impact location and pose of the ATD based on the sequence, quantifiable design, and articulation of ATD mount joints. This reporting method has been used to a limited extent in the literature, but we assert that adoption of this method will help to standardize the reporting of ATD headform pose and impact location as well as aid in the replication of impact test protocols across laboratories.
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15
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Champagne AA, Coverdale NS, Germuska M, Bhogal AA, Cook DJ. Changes in volumetric and metabolic parameters relate to differences in exposure to sub-concussive head impacts. J Cereb Blood Flow Metab 2020; 40:1453-1467. [PMID: 31307284 PMCID: PMC7308522 DOI: 10.1177/0271678x19862861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/11/2019] [Indexed: 01/15/2023]
Abstract
Structural and calibrated magnetic resonance imaging data were acquired on 44 collegiate football players prior to the season (PRE), following the first four weeks in-season (PTC) and one month after the last game (POST). Exposure data collected from g-Force accelerometers mounted to the helmet of each player were used to split participants into HIGH (N = 22) and LOW (N = 22) exposure groups, based on the frequency of impacts sustained by each athlete. Significant decreases in grey-matter volume specific to the HIGH group were documented at POST (P = 0.009), compared to baseline. Changes in resting cerebral blood flow (CBF0), corrected for partial volume effects, were observed within the HIGH group, throughout the season (P < 0.0001), suggesting that alterations in perfusion may follow exposure to sub-concussive collisions. Co-localized significant increases in cerebral metabolic rate of oxygen consumption (CMRO2|0) mid-season were also documented in the HIGH group, with respect to both PRE- and POST values. No physiological changes were observed in the LOW group. Therefore, cerebral metabolic demand may be elevated in players with greater exposure to head impacts. These results provide novel insight into the effects of sub-concussive collisions on brain structure and cerebrovascular physiology and emphasize the importance of multi-modal imaging for a complete characterization of cerebral health.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
| | - Mike Germuska
- Cardiff University Brain Research
Imaging Center, Cardiff University, Cardiff, UK
| | - Alex A Bhogal
- Department of Radiology, University
Medical Center Utrecht, Utrecht, The Netherlands
| | - Douglas J Cook
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
- Department of Surgery, Queen’s
University, Kingston, ON, Canada
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16
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Champagne AA, Distefano V, Boulanger MM, Magee B, Coverdale NS, Gallucci D, Guskiewicz K, Cook DJ. Data-informed Intervention Improves Football Technique and Reduces Head Impacts. Med Sci Sports Exerc 2020; 51:2366-2374. [PMID: 31269008 PMCID: PMC7028524 DOI: 10.1249/mss.0000000000002046] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Although sport participation is a key contributor to the physical and mental health of children and youth, exposure to subconcussive head impacts in football has raised concerns about safety for athletes. PURPOSE To demonstrate the efficacy of incorporating targeted football drills into a team's practice routine with the goal of improving players' technique and reduce exposure to subconcussive head impacts. METHODS Seventy high school football players (age, 16.4 ± 1.1 yr) were tested PRE season using a sport-specific functional assessment. Results from the testing were used to inform the design of a prepractice intervention aimed at improving tackling and blocking techniques while reducing exposure to head impacts. The assessment included drills which evaluated the players' ability to safely tackle, and block while simulating game-like situations. Testing was repeated at MID season (internal control) without an intervention, and again at POST season (experimental), after introduction of the prepractice intervention between these timepoints, administered twice weekly. All testing sessions were recorded, and subsequently reviewed by trained graders based on selected criteria defined by football coaches. A subset of 19 participants wore in-helmet accelerometers to assess the effectiveness of the intervention in decreasing head impacts during practice. RESULTS Significant improvements in blocking and tackling techniques were observed after the introduction of the intervention (P < 0.0001). Participating athletes also showed better techniques when evaluated in new game-like situations, postseason, providing evidence for proper acquisition and generalizability of these safer habits. Finally, frequency of head impacts (>15g) per practice was significantly reduced by ~30% after 1 month of training. CONCLUSION Our results suggest that data-informed methods can be used to improve coaching practices and promote safer play, which can have a positive public health impact moving forward.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, CANADA
| | - Vincent Distefano
- School of Applied Child Psychology, McGill Connections Lab, Montréal, QC, CANADA
| | | | - Blaire Magee
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, CANADA
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, CANADA
| | | | - Kevin Guskiewicz
- Matthew Gfeller Sport-Related TBI Research Center, University of North Carolina-Chapel Hill, Chapel Hill, NC
| | - Douglas J Cook
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, CANADA.,Department of Surgery, Queen's University, Kingston, ON, CANADA
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Correlation of Head Impact Exposures With Vestibulo-Ocular Assessments. J Sport Rehabil 2020; 29:310-314. [PMID: 30676193 DOI: 10.1123/jsr.2017-0282] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/07/2018] [Accepted: 12/28/2018] [Indexed: 11/18/2022]
Abstract
CONTEXT Managing a concussion injury should involve the incorporation of a multifaceted approach, including a vision assessment. The frontoparietal circuits and subcortical nuclei are susceptible to trauma from a concussion injury, leading to dysfunction of the vestibulo-ocular system. Research investigating the effect of cumulative subconcussive impacts on neurological function is still in its infancy, but repetitive head impacts may result in vestibular system dysfunction. This dysfunction could create visual deficits, predisposing the individual to further head trauma. OBJECTIVE The purpose of this study was to investigate the cumulative effect of subconcussive impacts on minimum perception time, static visual acuity, gaze stability, and dynamic visual acuity scores. DESIGN Prospective cohort. SETTING Division I university. PATIENTS Thirty-three Division I men's lacrosse players (age = 19.52 [1.20] y). INTERVENTION Competitive lacrosse season. MAIN OUTCOME MEASURES At the beginning and end of the season, the players completed a vestibulo-ocular reflex assessment, using the InVision™ system by Neurocom® to assess perception, static acuity, gaze stability, and dynamic visual acuity. Score differentials were correlated with the head impact exposure data collected via instrumented helmets. RESULTS A significant correlation was found between change in perception scores and total number of head impacts (r = .54), and between changes in dynamic visual acuity loss scores on the rightside and maximum rotational acceleration (r = .36). No statistical differences were found between preseason and postseason vestibulo-ocular reflex variables. CONCLUSIONS Cumulative subconcussive impacts may negatively affect vestibulo-ocular reflex scores, resulting in decreased visual performance. This decrease in vestibulo-ocular function may place the athlete at risk of sustaining additional head impacts or other injuries.
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18
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Relative Head Impact Exposure and Brain White Matter Alterations After a Single Season of Competitive Football: A Pilot Comparison of Youth Versus High School Football. Clin J Sport Med 2019; 29:442-450. [PMID: 31688173 DOI: 10.1097/jsm.0000000000000753] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Youth athletes are believed to be more susceptible to white matter (WM) degradation resulting from head impact exposure relative to high school (HS) athletes; this hypothesis has not been objectively tested. The purpose of this study was to determine preseason to postseason changes in WM integrity from repetitive head impacts for youth football (YFB) players compared with HS football players during a competitive football season. DESIGN Prospective cohort. SETTING One season of YFB (grades 7 and 8) and varsity HS football (grades 10-12). PATIENTS OR OTHER PARTICIPANTS Twelve YFB (13.08 ± 0.64 years) and 21 HS (17.5 ± 0.78 years) athletes. INTERVENTIONS Participants completed 2 magnetic resonance imaging sessions: preseason and postseason. Head impact exposure was recorded during practice and games using a helmet-mounted accelerometer. MAIN OUTCOME MEASURES Tract-based spatial statistics were used to evaluate group differences in preseason to postseason changes in diffusion tensor imaging, including fractional anisotropy and mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). RESULTS The HS group exhibited significant preseason to postseason reductions in MD, AD, and RD (P < 0.05, corrected) in widespread WM areas. Significant WM reductions for the YFB group were only observed for AD (P < 0.05, corrected), but was more limited in extent compared with HS. CONCLUSIONS Significant preseason to postseason AD reduction was found in both YFB and HS groups after one season of competitive play. Our results did not confirm recent speculation that younger children are more susceptible to the deleterious effects of repetitive head impacts compared with their older counterparts.
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19
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Champagne AA, Peponoulas E, Terem I, Ross A, Tayebi M, Chen Y, Coverdale NS, Nielsen PMF, Wang A, Shim V, Holdsworth SJ, Cook DJ. Novel strain analysis informs about injury susceptibility of the corpus callosum to repeated impacts. Brain Commun 2019; 1:fcz021. [PMID: 32954264 PMCID: PMC7425391 DOI: 10.1093/braincomms/fcz021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 01/08/2023] Open
Abstract
Increasing evidence for the cumulative effects of head trauma on structural integrity of the brain has emphasized the need to understand the relationship between tissue mechanic properties and injury susceptibility. Here, diffusion tensor imaging, helmet accelerometers and amplified magnetic resonance imaging were combined to gather insight about the region-specific vulnerability of the corpus callosum to microstructural changes in white-matter integrity upon exposure to sub-concussive impacts. A total of 33 male Canadian football players (meanage = 20.3 ± 1.4 years) were assessed at three time points during a football season (baseline pre-season, mid-season and post-season). The athletes were split into a LOW (N = 16) and HIGH (N = 17) exposure group based on the frequency of sub-concussive impacts sustained on a per-session basis, measured using the helmet-mounted accelerometers. Longitudinal decreases in fractional anisotropy were observed in anterior and posterior regions of the corpus callosum (average cluster size = 40.0 ± 4.4 voxels; P < 0.05, corrected) for athletes from the HIGH exposure group. These results suggest that the white-matter tract may be vulnerable to repetitive sub-concussive collisions sustained over the course of a football season. Using these findings as a basis for further investigation, a novel exploratory analysis of strain derived from sub-voxel motion of brain tissues in response to cardiac impulses was developed using amplified magnetic resonance imaging. This approach revealed specific differences in strain (and thus possibly stiffness) along the white-matter tract (P < 0.0001) suggesting a possible signature relationship between changes in white-matter integrity and tissue mechanical properties. In light of these findings, additional information about the viscoelastic behaviour of white-matter tissues may be imperative in elucidating the mechanisms responsible for region-specific differences in injury susceptibility observed, for instance, through changes in microstructural integrity following exposure to sub-concussive head impacts.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emile Peponoulas
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Itamar Terem
- Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, CA, USA
| | | | - Maryam Tayebi
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Yining Chen
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Poul M F Nielsen
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand.,Department of Engineering Science, Faculty of Engineering, University of Auckland, Auckland 1010, New Zealand
| | - Alan Wang
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Vickie Shim
- Auckland Bioengineering Institute, University of Auckland, Auckland Bioengineering House, L6, 70 Symonds Street, Auckland 1010, New Zealand
| | - Samantha J Holdsworth
- Department of Anatomy and Medical Imaging & Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand
| | - Douglas J Cook
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.,Department of Surgery, Queen's University, Kingston, ON, Canada
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20
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Development, Validation and Pilot Field Deployment of a Custom Mouthpiece for Head Impact Measurement. Ann Biomed Eng 2019; 47:2109-2121. [PMID: 31297724 DOI: 10.1007/s10439-019-02313-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/22/2019] [Indexed: 10/26/2022]
Abstract
The objective of this study was to develop a mouthpiece sensor with improved head kinematic measurement for use in non-helmeted and helmeted sports through laboratory validation and pilot field deployment in female youth soccer. For laboratory validation, data from the mouthpiece sensor was compared to standard sensors mounted in a headform at the center of gravity as the headform was struck with a swinging pendulum. Linear regression between peak kinematics measured from the mouthpiece and headform showed strong correlation, with r2 values of 0.95 (slope = 1.02) for linear acceleration, 1.00 (slope = 1.00) for angular velocity, and 0.97 (slope = 0.96) for angular acceleration. In field deployment, mouthpiece data were collected from four female youth soccer players and time-synchronized with film. Film-verified events (n = 915) were observed over 9 practices and 5 games, and 632 were matched to a corresponding mouthpiece event. This resulted in an overall sensitivity of 69.2% and a positive predictive value of 80.3%. This validation and pilot field deployment data demonstrates that the mouthpiece provides highly accurate measurement of on-field head impact data that can be used to further study the effects of impact exposure in both helmeted and non-helmeted sports.
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21
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Zuckerman SL, Reynolds BB, Yengo-Kahn AM, Kuhn AW, Chadwell JT, Goodale SE, Lafferty CE, Langford KT, McKeithan LJ, Kirby P, Solomon GS. A football helmet prototype that reduces linear and rotational acceleration with the addition of an outer shell. J Neurosurg 2019; 130:1634-1641. [PMID: 29957115 PMCID: PMC6289811 DOI: 10.3171/2018.1.jns172733] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/15/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Amid the public health controversy surrounding American football, a helmet that can reduce linear and rotational acceleration has the potential to decrease forces transmitted to the brain. The authors hypothesized that a football helmet with an outer shell would reduce both linear and rotational acceleration. The authors' objectives were to 1) determine an optimal material for a shock-absorbing outer shell and 2) examine the ability of an outer shell to reduce linear and/or rotational acceleration. METHODS A laboratory-based investigation was undertaken using an extra-large Riddell Revolution football helmet. Two materials (Dow Corning Dilatant Compound and Sorbothane) were selected for their non-Newtonian properties (changes in viscosity with shear stress) to develop an outer shell. External pads were attached securely to the helmet at 3 locations: the front boss, the side, and the back. The helmet was impacted 5 times per location at 6 m/sec with pneumatic ram testing. Two-sample t-tests were used to evaluate linear/rotational acceleration differences between a helmet with and a helmet without the outer shell. RESULTS Sorbothane was superior to the Dow Corning compound in force reduction and recovered from impact without permanent deformation. Of 5 different grades, 70-duro (a unit of hardness measured with a durometer) Sorbothane was found to have the greatest energy dissipation and stiffness, and it was chosen as the optimal outer-shell material. The helmet prototype with the outer shell reduced linear acceleration by 5.8% (from 75.4g to 71.1g; p < 0.001) and 10.8% (from 89.5g to 79.8g; p = 0.033) at the side and front boss locations, respectively, and reduced rotational acceleration by 49.8% (from 9312.8 rad/sec2 to 4671.7 rad/sed2; p < 0.001) at the front boss location. CONCLUSIONS Sorbothane (70 duro) was chosen as the optimal outer-shell material. In the outer-shell prototype helmet, the results demonstrated a 5%-10% reduction in linear acceleration at the side and front boss locations, and a 50% reduction in rotational acceleration at the front boss location. Given the paucity of publicly reported helmet-design literature and the importance of rotational acceleration in head injuries, the substantial reduction seen in rotational acceleration with this outer-shell prototype holds the potential for future helmet-design improvements.
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Affiliation(s)
- Scott L. Zuckerman
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
- Department of Neurological Surgery, Vanderbilt University School of Medicine
| | - Bryson B. Reynolds
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
- Department of Radiology, Vanderbilt University Medical Center
| | - Aaron M. Yengo-Kahn
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
- Department of Neurological Surgery, Vanderbilt University School of Medicine
| | - Andrew W. Kuhn
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
| | - Jacob T. Chadwell
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Sarah E. Goodale
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Claire E. Lafferty
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Kyle T. Langford
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Lydia J. McKeithan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Paul Kirby
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
| | - Gary S. Solomon
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine
- Department of Neurological Surgery, Vanderbilt University School of Medicine
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Caswell SV, Kelshaw P, Lincoln AE, Hepburn L, Dunn R, Cortes N. Game-Related Impacts in High School Boys' Lacrosse. Orthop J Sports Med 2019; 7:2325967119835587. [PMID: 31058198 PMCID: PMC6452429 DOI: 10.1177/2325967119835587] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background The rate of concussions in boys' lacrosse is reported to be the third highest among high school sports in the United States, but no studies have described game-related impacts among boys' lacrosse players. Purpose To characterize verified game-related impacts, both overall and those directly to the head, in boys' varsity high school lacrosse. Study Design Cross-sectional study; Level of evidence, 3. Methods A total of 77 male participants (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.05 m; mean weight, 73.4 ± 12.2 kg) were instrumented with sensors and were videotaped during 39 games. All verified game-related impacts ≥20g were summarized in terms of frequency, peak linear acceleration (PLA), and peak rotational velocity (PRV). Descriptive statistics and impact rates per player-game (PG) with corresponding 95% CIs were calculated. Results Overall, 1100 verified game-related impacts were recorded (PLA: median, 33.5g [interquartile range (IQR), 25.7-51.2]; PRV: median, 1135.5 deg/s [IQR, 790.0-1613.8]) during 795 PGs. The rate for all verified game-related impacts was 1.38 impacts per PG (95% CI, 1.30-1.47). Of these, 680 (61.8%) impacts (PLA: median, 35.9g [IQR, 26.7-55.5]; PRV: 1170.5 deg/s [IQR, 803.2-1672.8]) were directly to the head (impact rate, 0.86 impacts/PG [95% CI, 0.79-0.92]). Overall, midfielders (n = 514; 46.7%) sustained the most impacts, followed by attackers (n = 332; 30.2%), defenders (n = 233; 21.2%), and goalies (n = 21; 1.9%). The most common mechanisms for overall impacts and direct head impacts were contact with player (overall: n = 706 [64.2%]; head: n = 397 [58.4%]) and stick (overall: n = 303 [27.5%]; head: n = 239 [35.1%]), followed by ground (overall: n = 73 [6.6%]; head: n = 26 [3.8%]) and ball (overall: n = 15 [1.4%]; head: n = 15 [2.2%]). Direct head impacts were associated with a helmet-to-helmet collision 31.2% of the time, and they were frequently (53.7%) sustained by the players delivering the impact. Nearly half (48.8%) of players delivering contact used their helmets to initiate contact that resulted in a helmet-to-helmet impact. Players receiving a head impact from player contact were most often unprepared (75.9%) for the collision. Conclusion The helmet is commonly used to initiate contact in boys' high school lacrosse, often targeting defenseless opponents. Interventions to reduce head impacts should address rules and coaching messages to discourage intentional use of the helmet and encourage protection of defenseless opponents.
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Affiliation(s)
- Shane V Caswell
- Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia, USA
| | - Patricia Kelshaw
- Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia, USA
| | - Andrew E Lincoln
- MedStar Sports Medicine, Baltimore, Maryland, USA.,Department of Rehabilitation Medicine, Georgetown University Medical Center, Washington, D.C., USA
| | - Lisa Hepburn
- MedStar Sports Medicine, Baltimore, Maryland, USA
| | | | - Nelson Cortes
- Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia, USA
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McKeithan L, Hibshman N, Yengo-Kahn AM, Solomon GS, Zuckerman SL. Sport-Related Concussion: Evaluation, Treatment, and Future Directions. Med Sci (Basel) 2019; 7:medsci7030044. [PMID: 30884753 PMCID: PMC6473667 DOI: 10.3390/medsci7030044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/11/2019] [Accepted: 03/11/2019] [Indexed: 01/16/2023] Open
Abstract
Sport-related concussion (SRC) is a highly prevalent injury predominantly affecting millions of youth through high school athletes every year. In recent years, SRC has received a significant amount of attention due to potential for long-term neurologic sequelae. However, the acute symptoms and possibility of prolonged recovery account for the vast majority of morbidity from SRC. Modifying factors have been identified and may allow for improved prediction of a protracted course. Potential novel modifying factors may include genetic determinants of recovery, as well as radiographic biomarkers, which represent burgeoning subfields in SRC research. Helmet design and understanding the biomechanical stressors on the brain that lead to concussion also represent active areas of research. This narrative review provides a general synopsis of SRC, including relevant definitions, current treatment paradigms, and modifying factors for recovery, in addition to novel areas of research and future directions for SRC research.
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Affiliation(s)
- Lydia McKeithan
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Natalie Hibshman
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Aaron M Yengo-Kahn
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Gary S Solomon
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Scott L Zuckerman
- Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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24
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Carey L, Stanwell P, Terry DP, McIntosh AS, Caswell SV, Iverson GL, Gardner AJ. Verifying Head Impacts Recorded by a Wearable Sensor using Video Footage in Rugby League: a Preliminary Study. SPORTS MEDICINE - OPEN 2019; 5:9. [PMID: 30874938 PMCID: PMC6419663 DOI: 10.1186/s40798-019-0182-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/27/2019] [Indexed: 12/04/2022]
Abstract
BACKGROUND Rugby league is a full-contact collision sport with an inherent risk of concussion. Wearable instrumented technology was used to observe and characterize the level of exposure to head impacts during game play. PURPOSE To verify the impacts recorded by the x-patch™ with video analysis. STUDY DESIGN Observational case series. METHODS The x-patch™ was used on eight men's semi-professional rugby league players during the 2016 Newcastle Rugby League competition (five forwards and three backs). Game day footage was recorded by a trained videographer using a single camera located at the highest midfield location to verify the impact recorded by the x-patch™. Videographic and accelerometer data were time synchronized. RESULTS The x-patch™ sensors recorded a total of 779 impacts ≥ 20 g during the games, of which 732 (94.0%) were verified on video. In addition, 817 impacts were identified on video that did not record an impact on the sensors. The number of video-verified impacts ≥ 20 g, per playing hour, was 7.8 for forwards and 4.8 for backs (range = 3.9-19.0). Impacts resulting in a diagnosed concussion had much greater peak linear acceleration (M = 76.1 g, SD = 17.0) than impacts that did not result in a concussion (M = 34.2g, SD = 18.0; Cohen's d = 2.4). CONCLUSIONS The vast majority (94%) of impacts ≥ 20 g captured by the x-patch™ sensor were video verified in semi-professional rugby league games. The use of a secondary source of information to verify impact events recorded by wearable sensors is beneficial in clarifying game events and exposure levels.
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Affiliation(s)
- Lauchlan Carey
- Centre for Stroke and Brain Injury, School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, New South Wales Australia
| | - Peter Stanwell
- Centre for Stroke and Brain Injury, School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, New South Wales Australia
| | - Douglas P. Terry
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA USA
- Spaulding Rehabilitation Hospital, Boston, MA USA
- MassGeneral Hospital for Children™ Sport Concussion Program, & Home Base, A Red Sox Foundation and Massachusetts General Hospital Program, Boston, MA USA
| | - Andrew S. McIntosh
- School of Engineering and Australian Collaboration for Research into Injury in Sport and its Prevention, Edith Cowan University, Perth, Western Australia Australia
- Monash University Accident Research Centre, Monash University, Clayton, Victoria Australia
| | - Shane V. Caswell
- Sports Medicine Assessment Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia USA
| | - Grant L. Iverson
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA USA
- Spaulding Rehabilitation Hospital, Boston, MA USA
- MassGeneral Hospital for Children™ Sport Concussion Program, & Home Base, A Red Sox Foundation and Massachusetts General Hospital Program, Boston, MA USA
| | - Andrew J. Gardner
- Hunter New England Local Health District Sports Concussion Program, New Lambton Heights, New South Wales Australia
- Centre for Stroke and Brain Injury, School of Medicine and Public Health, University of Newcastle, Callaghan, New South Wales Australia
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Champagne AA, Coverdale NS, Nashed JY, Fernandez-Ruiz J, Cook DJ. Resting CMRO 2 fluctuations show persistent network hyper-connectivity following exposure to sub-concussive collisions. Neuroimage Clin 2019; 22:101753. [PMID: 30884366 PMCID: PMC6424143 DOI: 10.1016/j.nicl.2019.101753] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 02/20/2019] [Accepted: 03/09/2019] [Indexed: 12/20/2022]
Abstract
Exposure to head impacts may alter brain connectivity within cortical hubs such as the default-mode network (DMN). However, studies have yet to consider the confounding effects of altered resting cerebral blood flow (CBF0) and cerebrovascular reactivity (CVR) on changes in connectivity following sub-concussive impacts. Here, 23 Canadian collegiate football players were followed during a season using calibrated resting-state MRI and helmet accelerometers to examine the interplay between the neural and vascular factors that determine functional connectivity (FC). Connectivity-based analyses using blood oxygen level dependent (BOLD) and cerebral metabolic rate of oxygen consumption (CMRO2) mapping were used to study the DMN longitudinally. Network-specific decreases in CBF0 were observed one month following the season, while impaired CVR was documented at both mid-season and one month following the season, compared to pre-season baseline. Alterations in CBF0 and BOLD-based CVR throughout the season suggest that neurophysiological markers may show different susceptibility timelines following head impacts. DMN connectivity was increased throughout the season, independent of changes in cerebrovascular physiology, suggesting that alterations in FC following sub-concussive impacts are robust and independent of changes in brain hemodynamics. No significant correlations between impact kinematics and DMN connectivity changes were documented in this study. Altogether, these findings create a strong paradigm for future studies to examine the underlying neural and vascular mechanisms associated with increases in network connectivity following repeated exposure to sub-concussive collisions, in an effort to improve management of head impacts in contact sports.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Joseph Y Nashed
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Juan Fernandez-Ruiz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, Ciudad de México 04510, México.
| | - Douglas J Cook
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada; Department of Surgery, Queen's University, Room 232, 18 Stuart St, Kingston, ON K7L 3N6, Canada.
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Joodaki H, Bailey A, Lessley D, Funk J, Sherwood C, Crandall J. Relative Motion between the Helmet and Head in Football Impact Test. J Biomech Eng 2019; 141:2727820. [PMID: 30835289 DOI: 10.1115/1.4043038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Indexed: 11/08/2022]
Abstract
Approximately 1.6-3.8 million sports-related traumatic brain injuries occur each year in the US. Researchers track the head motion using a variety of techniques to study the head injury biomechanics. To understand how helmets provide head protection, quantification of the relative motion between the head and the helmet is necessary. The purpose of this study was to compare helmet and head kinematics and quantify the relative motion of helmet with respect to head during experimental representations of on-field American football impact scenarios. Seven helmet-to-helmet impact configurations were simulated by propelling helmeted crash test dummies into each other. Head and helmet kinematics were measured with instrumentation and an optical motion capture system. The analysis of results showed that, the helmets translated 12 - 41 mm and rotated up to 37 degrees with respect to the head. The peak resultant linear acceleration of the helmet was about 2 - 5 times higher than the head. The peak resultant angular velocity of the helmet ranged from 37% less to 71% more than the head, depending on the impact conditions. The results of this study demonstrate that the kinematics of the head and helmet are noticeably different and that the helmet rotates significantly with respect to the head during impacts. Therefore, capturing the helmet kinematics using a video motion tracking methodology is not sufficient to study the biomechanics of the head. Head motion must be measured independently of the helmet.
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Affiliation(s)
- Hamed Joodaki
- Center for Applied Biomechanics, Department of Mechanical and Aerospace Engineering, University of Virginia, 4040 Lewis and Clark Drive, Charlottesville, VA 22911, USA
| | - Ann Bailey
- Biocore LLC, 1621 Quail Run, Charlottesville, VA 22911, USA
| | - David Lessley
- Biocore LLC, 1621 Quail Run, Charlottesville, VA 22911, USA
| | - James Funk
- Biocore LLC, 1621 Quail Run, Charlottesville, VA 22911, USA
| | - Chris Sherwood
- Biocore LLC, 1621 Quail Run, Charlottesville, VA 22911, USA
| | - Jeff Crandall
- Center for Applied Biomechanics, Department of Mechanical and Aerospace Engineering, University of Virginia, 4040 Lewis and Clark Drive, Charlottesville, VA 22911, USA
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McIntosh AS, Willmott C, Patton DA, Mitra B, Brennan JH, Dimech-Betancourt B, Howard TS, Rosenfeld JV. An assessment of the utility and functionality of wearable head impact sensors in Australian Football. J Sci Med Sport 2019; 22:784-789. [PMID: 31000457 DOI: 10.1016/j.jsams.2019.02.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/05/2019] [Accepted: 02/21/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To assess the utility and functionality of the X-Patch® as a measurement tool to study head impact exposure in Australian Football. Accuracy, precision, reliability and validity were examined. DESIGNS Laboratory tests and prospective observational study. METHODS Laboratory tests on X-Patch® were undertaken using an instrumented Hybrid III head and neck and linear impactor. Differences between X-Patch® and reference data were analysed. Australian Football players wore the X-Patch® devices and games were video-recorded. Video recordings were analysed qualitatively for head impact events and these were correlated with X-Patch® head acceleration events. Wearability of the X-Patch® was assessed using the Comfort Rating Scale for Wearable Computers. RESULTS Laboratory head impacts, performed at multiple impact sites and velocities, identified significant correlations between headform-measured and device-measured kinematic parameters (p<0.05 for all). On average, the X-Patch®-recorded peak linear acceleration (PLA) was 17% greater than the reference PLA, 28% less for peak rotational acceleration (PRA) and 101% greater for the Head Injury Criterion (HIC). For video analysis, 118 head acceleration events (HAE) were included with PLA ≥30g across 53 players. Video recordings of X-Patch®-measured HAEs (PLA ≥30g) determined that 31.4% were direct head impacts, 9.3% were indirect impacts, 44.1% were unknown or unclear and 15.3% were neither direct nor indirect head impacts. The X-Patch® system was deemed wearable by 95-100% of respondents. CONCLUSIONS This study reinforces evidence that use of the current X-Patch® devices should be limited to research only and in conjunction with video analysis.
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Affiliation(s)
- Andrew S McIntosh
- MUARC, Monash University, Melbourne, Australia; Federation University Australia, Ballarat, Australia.
| | - Catherine Willmott
- Monash Institute of Cognitive & Clinical Neurosciences, School of Psychological Sciences, Monash University, Melbourne, Australia; Monash-Epworth Rehabilitation Research Centre, Epworth Hospital, Melbourne, Australia
| | | | - Biswadev Mitra
- National Trauma Research Institute, The Alfred Hospital, Melbourne, Australia; Department of Epidemiology & Preventive Medicine, Monash University, Melbourne, Australia
| | - James H Brennan
- National Trauma Research Institute, The Alfred Hospital, Melbourne, Australia
| | - Bleydy Dimech-Betancourt
- Monash Institute of Cognitive & Clinical Neurosciences, School of Psychological Sciences, Monash University, Melbourne, Australia; Monash-Epworth Rehabilitation Research Centre, Epworth Hospital, Melbourne, Australia
| | - Teresa S Howard
- National Trauma Research Institute, The Alfred Hospital, Melbourne, Australia; Department of Surgery, Monash University, Melbourne, Australia
| | - Jeffrey V Rosenfeld
- Department of Neurosurgery, The Alfred Hospital, Melbourne, Australia; Department of Surgery, Monash University, Melbourne, Australia
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Tiernan S, O’Sullivan D, Byrne G. Repeatability and Reliability Evaluation of a Wireless Head-band Sensor. THE ASIAN JOURNAL OF KINESIOLOGY 2018. [DOI: 10.15758/ajk.2018.20.4.70] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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29
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Myer GD, Barber Foss K, Thomas S, Galloway R, DiCesare CA, Dudley J, Gadd B, Leach J, Smith D, Gubanich P, Meehan Iii WP, Altaye M, Lavin P, Yuan W. Altered brain microstructure in association with repetitive subconcussive head impacts and the potential protective effect of jugular vein compression: a longitudinal study of female soccer athletes. Br J Sports Med 2018; 53:1539-1551. [PMID: 30323056 DOI: 10.1136/bjsports-2018-099571] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2018] [Indexed: 12/28/2022]
Abstract
PURPOSE To (1) quantify white matter (WM) alterations in female high school athletes during a soccer season and characterise the potential for normalisation during the off-season rest period, (2) determine the association between WM alterations and exposure to repetitive subconcussive head impacts, and (3) evaluate the efficacy of a jugular vein compression collar to prevent WM alterations associated with head impact exposure. METHODS Diffusion tensor imaging (DTI) data were prospectively collected from high school female soccer participants (14-18 years) at up to three time points over 9 months. Head impacts were monitored using accelerometers during all practices and games. Participants were assigned to a collar (n=24) or non-collar group (n=22). The Tract-Based Spatial Statistics approach was used in the analysis of within-group longitudinal change and between-group comparisons. RESULTS DTI analyses revealed significant pre-season to post-season WM changes in the non-collar group in mean diffusivity (2.83%±2.46%), axial diffusivity (2.58%±2.34%) and radial diffusivity (3.52%±2.60%), but there was no significant change in the collar group despite similar head impact exposure. Significant correlation was found between head impact exposure and pre-season to post-season DTI changes in the non-collar group. WM changes in the non-collar group partially resolved at 3 months off-season follow-up. DISCUSSION Microstructural changes in WM occurred during a season of female high school soccer among athletes who did not wear the collar device. In comparison, there were no changes in players who wore the collar, suggesting a potential prophylactic effect of the collar device in preventing changes associated with repetitive head impacts. In those without collar use, the microstructural changes showed a reversal towards normal over time in the off-season follow-up period.
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Affiliation(s)
- Gregory D Myer
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Departments of Pediatrics and Orthopaedic Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA.,Duke University School of Medicine, Durham, North Carolina, USA
| | - Kim Barber Foss
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Staci Thomas
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ryan Galloway
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Christopher A DiCesare
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jonathan Dudley
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Brooke Gadd
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - James Leach
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - David Smith
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul Gubanich
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | | | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Philip Lavin
- Boston Biostatistics Research Foundation, Framingham, Massachusetts, USA
| | - Weihong Yuan
- University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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30
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Buice JM, Esquivel AO, Andrecovich CJ. Laboratory Validation of a Wearable Sensor for the Measurement of Head Acceleration in Men's and Women's Lacrosse. J Biomech Eng 2018; 140:2682435. [PMID: 30029242 DOI: 10.1115/1.4040311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Indexed: 11/08/2022]
Abstract
Mild traumatic brain injuries, or concussions, can result from head acceleration during sports. Wearable sensors like the GForceTrackerTM (GFT) can monitor an athlete's head acceleration during play. The purpose of this study was to evaluate the accuracy of the GFT for use in boys' and girls' lacrosse. The GFT was mounted to either a strap connected to lacrosse goggles (helmetless) or a helmet. The assembly was fit to a Hybrid III (HIII) headform instrumented with sensors and impacted multiple times at different velocities and locations. Measurements of peak linear acceleration and angular velocity were obtained from both systems and compared. It was found that a large percent error between the GFT and headform system existed for linear acceleration (29% for helmetless and 123% for helmet) and angular velocity (48% for helmetless and 17% for helmet). Linear acceleration data transformed to the center of gravity (CG) of the head still produced errors (47% for helmetless and 76% for helmet). This error was substantially reduced when correction equations were applied based on impact location (3-22% for helmetless and 3-12% for helmet impacts at the GFT location and transformed to the CG of the head). Our study has shown that the GFT does not accurately calculate linear acceleration or angular velocity at the CG of the head; however, reasonable error can be achieved by correcting data based on impact location.
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Affiliation(s)
- Jessica M Buice
- Department of Mechanical Engineering, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, MI 48128 e-mail:
| | - Amanda O Esquivel
- Department of Mechanical Engineering, University of Michigan-Dearborn, , Dearborn, MI 48128 e-mail:
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31
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Brokaw EB, Fine MS, Kindschi KE, Santago Ii AC, Lum PS, Higgins M. Cross-sectional evaluation of visuomotor tracking performance following subconcussive head impacts. Technol Health Care 2018; 26:109-118. [PMID: 29125529 DOI: 10.3233/thc-171079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Repeated mild traumatic brain injury (mTBI) has been associated with increased risk of degenerative neurological disorders. While the effects of mTBI and repeated injury are known, studies have only recently started examining repeated subconcussive impacts, impacts that do not result in a clinically diagnosed mTBI. In these studies, repeated subconcussive impacts have been connected to cognitive performance and brain imaging changes. OBJECTIVE Recent research suggests that performance on a visuomotor tracking (VMT) task may help improve the identification of mTBI. The goal of this study was to investigate if VMT performance is sensitive to the cumulative effect of repeated subconcussive head impacts in collegiate men's lacrosse players. METHODS A cross-sectional, prospective study was completed with eleven collegiate men's lacrosse players. Participants wore helmet-mounted sensors and completed VMT and reaction time assessments. The relationship between cumulative impact metrics and VMT metrics were investigated. RESULTS In this study, VMT performance correlated with repeated subconcussive head impacts; individuals approached clinically diagnosed mTBI-like performance as the cumulative rotational velocity they experienced increased. CONCLUSION This suggests that repeated subconcussive impacts can result in measurable impairments and indicates that visuomotor tracking performance may be a useful tool for monitoring the effects of repeated subconcussive impacts.
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Affiliation(s)
- E B Brokaw
- Emerging Technologies Department, The MITRE Corporation, McLean, VA, USA
| | - M S Fine
- Emerging Technologies Department, The MITRE Corporation, McLean, VA, USA
| | - K E Kindschi
- Department of Sports Medicine, The MedStar Health Union Memorial Hospital, Baltimore, MD, USA
| | - A C Santago Ii
- Emerging Technologies Department, The MITRE Corporation, McLean, VA, USA
| | - P S Lum
- Center for Applied Biomechanics and Rehabilitation Research, The MedStar Health National Rehabilitation Hospital, Washington, DC, USA.,Department of Biomedical Engineering, The Catholic University of America, Washington, DC, USA
| | - M Higgins
- Kinesiology Department, Towson University, Towson, MD, USA
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32
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Kuo C, Sganga J, Fanton M, Camarillo DB. Head Impact Kinematics Estimation With Network of Inertial Measurement Units. J Biomech Eng 2018; 140:2679247. [PMID: 29801166 DOI: 10.1115/1.4039987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Indexed: 11/08/2022]
Abstract
Wearable sensors embedded with inertial measurement units have become commonplace for the measurement of head impact biomechanics, but individual systems often suffer from a lack of measurement fidelity. While some researchers have focused on developing highly accurate, single sensor systems, we have taken a parallel approach in investigating optimal estimation techniques with multiple noisy sensors. In this work, we present a sensor network methodology that utilizes multiple skin patch sensors arranged on the head and combines their data to obtain a more accurate estimate than any individual sensor in the network. Our methodology visually localizes subject-specific sensor transformations, and based on rigid body assumptions, applies estimation algorithms to obtain a minimum mean squared error estimate. During mild soccer headers, individual skin patch sensors had over 100% error in peak angular velocity magnitude, angular acceleration magnitude, and linear acceleration magnitude. However, when properly networked using our visual localization and estimation methodology, we obtained kinematic estimates with median errors below 20%. While we demonstrate this methodology with skin patch sensors in mild soccer head impacts, the formulation can be generally applied to any dynamic scenario, such as measurement of cadaver head impact dynamics using arbitrarily placed sensors.
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Affiliation(s)
- Calvin Kuo
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305 e-mail:
| | - Jake Sganga
- Department of Bioengineering, Stanford University, Stanford, CA 94305 e-mail:
| | - Michael Fanton
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305 e-mail:
| | - David B Camarillo
- Professor Department of Bioengineering, Stanford University, Stanford, CA 94305 e-mail:
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33
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Laboratory Evaluation of Low-Cost Wearable Sensors for Measuring Head Impacts in Sports. J Appl Biomech 2018; 34:320-326. [DOI: 10.1123/jab.2017-0256] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Advances in low-cost wearable head impact sensor technology provide potential benefits regarding sports safety for both consumers and researchers. However, previous laboratory evaluations are not directly comparable and do not incorporate test conditions representative of unhelmeted impacts. This study addresses those limitations. The xPatch by X2 Biosystems and the SIM-G by Triax Technologies were placed on a National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform with a Hybrid III neck which underwent impact tests using a pendulum. Impact conditions included helmeted, padded impactor to bare head, and rigid impactor to bare head to represent long- and short-duration impacts seen in helmeted and unhelmeted sports. The wearable sensors were evaluated on their kinematic accuracy by comparing results to reference sensors located at the headform center of gravity. Statistical tests for equivalence were performed on the slope of the linear regression between wearable sensors and reference. The xPatch gave equivalent measurements to the reference in select longer-duration impacts, whereas the SIM-G had large variance leading to no equivalence. For the short-duration impacts, both wearable sensors underpredicted the reference. This error can be improved with increases in sampling rate from 1 to 1.5 kHz. Follow-up evaluations should be performed on the field to identify error in vivo.
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Kuo C, Wu L, Loza J, Senif D, Anderson SC, Camarillo DB. Comparison of video-based and sensor-based head impact exposure. PLoS One 2018; 13:e0199238. [PMID: 29920559 PMCID: PMC6007917 DOI: 10.1371/journal.pone.0199238] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Accepted: 06/04/2018] [Indexed: 11/18/2022] Open
Abstract
Previous research has sought to quantify head impact exposure using wearable kinematic sensors. However, many sensors suffer from poor accuracy in estimating impact kinematics and count, motivating the need for additional independent impact exposure quantification for comparison. Here, we equipped seven collegiate American football players with instrumented mouthguards, and video recorded practices and games to compare video-based and sensor-based exposure rates and impact location distributions. Over 50 player-hours, we identified 271 helmet contact periods in video, while the instrumented mouthguard sensor recorded 2,032 discrete head impacts. Matching video and mouthguard real-time stamps yielded 193 video-identified helmet contact periods and 217 sensor-recorded impacts. To compare impact locations, we binned matched impacts into frontal, rear, side, oblique, and top locations based on video observations and sensor kinematics. While both video-based and sensor-based methods found similar location distributions, our best method utilizing integrated linear and angular position only correctly predicted 81 of 217 impacts. Finally, based on the activity timeline from video assessment, we also developed a new exposure metric unique to American football quantifying number of cross-verified sensor impacts per player-play. We found significantly higher exposure during games (0.35, 95% CI: 0.29-0.42) than practices (0.20, 95% CI: 0.17-0.23) (p<0.05). In the traditional impacts per player-hour metric, we observed higher exposure during practices (4.7) than games (3.7) due to increased player activity in practices. Thus, our exposure metric accounts for variability in on-field participation. While both video-based and sensor-based exposure datasets have limitations, they can complement one another to provide more confidence in exposure statistics.
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Affiliation(s)
- Calvin Kuo
- Department of Mechanical Engineering, Stanford University, Stanford CA, United States of America
| | - Lyndia Wu
- Department of Bioengineering, Stanford University, Stanford CA, United States of America
| | - Jesus Loza
- Department of Mechanical Engineering, Stanford University, Stanford CA, United States of America
| | - Daniel Senif
- Stanford Sports Medicine, Stanford University, Stanford CA, United States of America
| | - Scott C. Anderson
- Stanford Sports Medicine, Stanford University, Stanford CA, United States of America
| | - David B. Camarillo
- Department of Mechanical Engineering, Stanford University, Stanford CA, United States of America
- Department of Bioengineering, Stanford University, Stanford CA, United States of America
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35
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Miyashita TL, Diakogeorgiou E, Marrie K. The role of subconcussive impacts on sway velocities in Division I men's lacrosse players. Sports Biomech 2018; 19:180-188. [PMID: 29754531 DOI: 10.1080/14763141.2018.1458892] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Head impacts resulting in a concussion negatively affect the vestibular system, but little is known about the effect of subconcussive impacts on this system. This study's objective was to determine if subconcussive head impacts sustained over one competitive lacrosse season, effect sway velocity. Healthy Division I male lacrosse players (n = 33; aged 19.52 ± 1.20 years) wore instrumented helmets to track head impact exposures. At the beginning and end of the season the players completed an instrumented Balance Error Scoring System assessment to assess sway velocity. Score differentials were correlated to the head impact exposure data collected via instrumented helmets when averaged within participant. Paired samples t-tests revealed a post-season increase in sway velocity on the double leg stance, firm surface (p = 0.002, d = 0.59); tandem stance, firm surface (p = 0.033, d = 0.39) and double leg, foam surface (p = 0.014, d = 0.45) A significant correlation was found between change in tandem stance, firm surface sway velocities and linear acceleration (p < 0.001, r = 0.65). It appears subconcussive impacts may result in tandem stance balance deficits. Repetitive head impacts may negatively affect sway velocity, even in the absence of a diagnosed concussion injury.
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Affiliation(s)
| | | | - Kaitlyn Marrie
- Athletic Training Department, Sacred Heart University, Fairfield, CT, USA
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36
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Abstract
Background Gaining a better understanding of head impact exposures may lead to better comprehension of the possible effects of repeated impact exposures not associated with clinical concussion. Purpose To assess the correlation between head impacts and any differences associated with cognitive testing measurements pre- and postseason. Study Design Case-control study; Level of evidence, 3. Methods A total of 34 National Collegiate Athletic Association Division I men's lacrosse players wore lacrosse helmets instrumented with an accelerometer during the 2014 competitive season and were tested pre- and postseason with the Sport Concussion Assessment Tool (SCAT 3) and Concussion Vital Signs (CVS) computer-based neurocognitive tests. The number of head impacts >20g and results from the 2 cognitive tests were analyzed for differences and correlation. Results There was no significant difference between pre- and postseason SCAT 3 scores, although a significant correlation between pre- and postseason cognitive scores on the SCAT 3 and total number of impacts sustained was noted (r = -0.362, P = .035). Statistically significant improvements on half of the CVS testing components included visual reaction time (P = .037, d = 0.37), reaction time (P = .001, d = 0.65), and simple reaction time (P = .043, d = 0.37), but no correlation with head impacts was noted. Conclusion This study did not find declines in SCAT 3 or CVS scores over the course of a season among athletes who sustained multiple head impacts but no clinical concussion. Thus, it could not be determined whether there was no cognitive decline among these athletes or whether there may have been subtle declines that could not be measured by the SCAT 3 or CVS.
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37
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Miller LE, Kuo C, Wu LC, Urban JE, Camarillo DB, Stitzel JD. Validation of a Custom Instrumented Retainer Form Factor for Measuring Linear and Angular Head Impact Kinematics. J Biomech Eng 2018; 140:2671738. [DOI: 10.1115/1.4039165] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Indexed: 11/08/2022]
Abstract
Head impact exposure in popular contact sports is not well understood, especially in the youth population, despite recent advances in impact-sensing technology which has allowed widespread collection of real-time head impact data. Previous studies indicate that a custom-instrumented mouthpiece is a superior method for collecting accurate head acceleration data. The objective of this study was to evaluate the efficacy of mounting a sensor device inside an acrylic retainer form factor to measure six-degrees-of-freedom (6DOF) head kinematic response. This study compares 6DOF mouthpiece kinematics at the head center of gravity (CG) to kinematics measured by an anthropomorphic test device (ATD). This study found that when instrumentation is mounted in the rigid retainer form factor, there is good coupling with the upper dentition and highly accurate kinematic results compared to the ATD. Peak head kinematics were correlated with r2 > 0.98 for both rotational velocity and linear acceleration and r2 = 0.93 for rotational acceleration. These results indicate that a rigid retainer-based form factor is an accurate and promising method of collecting head impact data. This device can be used to study head impacts in helmeted contact sports such as football, hockey, and lacrosse as well as nonhelmeted sports such as soccer and basketball. Understanding the magnitude and frequency of impacts sustained in various sports using an accurate head impact sensor, such as the one presented in this study, will improve our understanding of head impact exposure and sports-related concussion.
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Affiliation(s)
- Logan E. Miller
- School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106
- Department of Biomedical Engineering, Wake Forest School of Medicine, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106 e-mail:
| | - Calvin Kuo
- Department of Mechanical Engineering, Stanford University, 443 Via Ortega, Room 202, Stanford, CA 94305 e-mail:
| | - Lyndia C. Wu
- Department of Bioengineering, Stanford University, 443 Via Ortega, Room 202, Stanford, CA 94305 e-mail:
| | - Jillian E. Urban
- School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106
- Department of Biomedical Engineering, Wake Forest School of Medicine, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106; Clinical and Translational Science Institute, Wake Forest School of Medicine, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106 e-mail:
| | - David B. Camarillo
- Department of Bioengineering, Stanford University, 443 Via Ortega, Room 202, Stanford, CA 94305
- Clinical and Translational Science Institute, Wake Forest School of Medicine, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106 e-mail:
| | - Joel D. Stitzel
- School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106
- Department of Biomedical Engineering, Wake Forest School of Medicine, 575 N. Patterson Avenue, Suite 120, Winston-Salem, NC 27106 e-mail:
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38
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Trotta A, Zouzias D, De Bruyne G, Ní Annaidh A. The Importance of the Scalp in Head Impact Kinematics. Ann Biomed Eng 2018; 46:831-840. [PMID: 29497893 DOI: 10.1007/s10439-018-2003-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/23/2018] [Indexed: 11/27/2022]
Abstract
The best way to reduce the risk of head injury (up to 69% reduction) is to wear a helmet. In recent years, the improvement of helmet standard tests focused on reproducing realistic impact conditions and including the effect of rotational acceleration. However, less importance has been given to the development of a realistic headform. The goal of this work was to evaluate the role of scalp tissue in head impact kinematics; both with respect to its mechanical properties and with respect to its sliding properties. An EN960 and HIII headform were subjected to linear and oblique impacts, respectively, both with and without porcine scalp attached. Different speeds, impact locations and impact surfaces were tested. Standard linear drop tests (EN960) showed that the scalp reduced the impact energy by up to 68.7% (rear impact). Oblique head impact tests showed how the headform-anvil friction coefficient changes when the HIII is covered with scalp, affecting linear and rotational accelerations. Therefore, the scalp plays an important role in head impacts and it should be realistically represented in headforms used for impact tests and in numerical models of the human head.
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Affiliation(s)
- Antonia Trotta
- UCD School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitris Zouzias
- LazerSport, Lamorierestraat 33, Antwerp, Belgium.,Department of Materials Engineering, KU Leuven, Louvain, Belgium
| | - Guido De Bruyne
- LazerSport, Lamorierestraat 33, Antwerp, Belgium.,Product Development, Faculty of Design Sciences, University of Antwerp, Antwerp, Belgium
| | - Aisling Ní Annaidh
- UCD School of Mechanical & Materials Engineering, University College Dublin, Belfield, Dublin 4, Ireland. .,School of Medicine and Medical Science, UCD Charles Institute of Dermatology, University College Dublin, Belfield, Dublin 4, Ireland.
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39
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Rowson B, Tyson A, Rowson S, Duma S. Measuring head impacts: accelerometers and other sensors. HANDBOOK OF CLINICAL NEUROLOGY 2018; 158:235-243. [PMID: 30482351 DOI: 10.1016/b978-0-444-63954-7.00023-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding the biomechanics of head injuries is essential for the development of preventive strategies and protective equipment design. However, there are many challenges associated with determining the forces that cause injury. Acceleration of the skull is often measured because it is relatively easy to quantify and relates to severity of impact, but it is difficult to relate those measurements to the type and extent of injury that occurs. Experimental work in the laboratory has used either human cadavers or volunteers. Cadavers can be instrumented with high-grade sensors that are tightly coupled to the skull for accurate measurements, but they cannot exhibit a functional response to determine a threshold for brain injury. Volunteers can also be instrumented with high-grade sensors in controlled laboratory experiments, but any head accelerations they experience must be well below an injurious level. Athletes participating in contact sports present a unique opportunity to collect biomechanical data from populations that have increased exposure to head impacts and a higher risk of head injury than the general population. Recent advances in sensor technology have allowed for more accurate measurements from instrumented athletes during play, but it is challenging to tightly couple the instrumentation to the skull to provide meaningful measurements. Because of the challenges associated with on-field measurements, it is important to consider the type of sensor used and its accuracy in the field when evaluating head impact data from athletes.
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Affiliation(s)
- Bethany Rowson
- Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA, United States
| | - Abigail Tyson
- Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA, United States
| | - Steven Rowson
- Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA, United States
| | - Stefan Duma
- Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA, United States.
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40
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Yuan W, Barber Foss KD, Thomas S, DiCesare CA, Dudley JA, Kitchen K, Gadd B, Leach JL, Smith D, Altaye M, Gubanich P, Galloway RT, McCrory P, Bailes JE, Mannix R, Meehan WP, Myer GD. White matter alterations over the course of two consecutive high-school football seasons and the effect of a jugular compression collar: A preliminary longitudinal diffusion tensor imaging study. Hum Brain Mapp 2017; 39:491-508. [PMID: 29080230 DOI: 10.1002/hbm.23859] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 10/12/2017] [Accepted: 10/16/2017] [Indexed: 12/23/2022] Open
Abstract
The cumulative effects of repetitive subclinical head impacts during sports may result in chronic white matter (WM) changes and possibly, neurodegenerative sequelae. In this pilot study, we investigated the longitudinal WM changes over the course of two consecutive high-school football seasons and explored the long-term effects of a jugular vein compression collar on these WM alterations. Diffusion tensor imaging data were prospectively collected both pre- and postseason in the two consecutive seasons. Participants were assigned into either collar or noncollar groups. Tract-based spatial statistics (TBSS) approach and region of interest-based approach were used to quantify changes in WM diffusion properties. Despite comparable exposure to repetitive head impacts, significant reductions in mean, axial, and/or radial diffusivity were identified in Season 1 in multiple WM regions in the noncollar group but not in the collar group. After an 8- to 9-month long off-season, these changes observed in the noncollar group partially and significantly reversed but also remained significantly different from the baseline. In Season 2, trend level WM alterations in the noncollar group were found but located in spatially different regions than Season 1. Last, the WM integrity in the collar group remained unchanged throughout the four time points. In conclusion, we quantitatively assessed the WM structural changes and partial reversal over the course of two consecutive high-school football seasons. In addition, the mitigated WM alterations in athletes in the collar group might indicate potential effect of the collar in ameliorating the changes against repetitive head impacts. Hum Brain Mapp 39:491-508, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Weihong Yuan
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Radiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Kim D Barber Foss
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Staci Thomas
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Christopher A DiCesare
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Jonathan A Dudley
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Katie Kitchen
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Brooke Gadd
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - James L Leach
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Radiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - David Smith
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Paul Gubanich
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ryan T Galloway
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Paul McCrory
- The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
| | - Julian E Bailes
- Department of Neurosurgery, NorthShore University Health System, Evanston, Illinois
| | - Rebekah Mannix
- The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts
| | - William P Meehan
- The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts
| | - Gregory D Myer
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts.,Departments of Pediatrics and Orthopaedic Surgery, University of Cincinnati, Cincinnati, Ohio.,Department of Orthopaedics, University of Pennsylvania, Philadelphia, Pennsylvania
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41
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Mihalik JP, Lynall RC, Wasserman EB, Guskiewicz KM, Marshall SW. Evaluating the "Threshold Theory": Can Head Impact Indicators Help? Med Sci Sports Exerc 2017; 49:247-253. [PMID: 27580157 DOI: 10.1249/mss.0000000000001089] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to determine the clinical utility of biomechanical head impact indicators by measuring the sensitivity, specificity, positive predictive value (PV+), and negative predictive value (PV-) of multiple thresholds. METHODS Head impact biomechanics (n = 283,348) from 185 football players in one Division I program were collected. A multidisciplinary clinical team independently made concussion diagnoses (n = 24). We dichotomized each impact using diagnosis (yes = 24, no = 283,324) and across a range of plausible impact indicator thresholds (10g increments beginning with a resultant linear head acceleration of 50g and ending with 120g). RESULTS Some thresholds had adequate sensitivity, specificity, and PV-. All thresholds had low PV+, with the best recorded PV+ less than 0.4% when accounting for all head impacts sustained by our sample. Even when conservatively adjusting the frequency of diagnosed concussions by a factor of 5 to account for unreported/undiagnosed injuries, the PV+ of head impact indicators at any threshold was no greater than 1.94%. CONCLUSIONS Although specificity and PV- appear high, the low PV+ would generate many unnecessary evaluations if these indicators were the sole diagnostic criteria. The clinical diagnostic value of head impact indicators is considerably questioned by these data. Notwithstanding, valid sensor technologies continue to offer objective data that have been used to improve player safety and reduce injury risk.
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Affiliation(s)
- Jason P Mihalik
- 1Department of Exercise and Sport Science, Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center, The University of North Carolina, Chapel Hill, NC; 2Curriculum in Human Movement Science, Department of Allied Health Sciences, School of Medicine, The University of North Carolina, Chapel Hill, NC; 3Injury Prevention Research Center, The University of North Carolina, Chapel Hill, NC; 4Department of Kinesiology, The University of Georgia, Athens, GA; 5Datalys Center, Indianapolis, IN; and 6Department of Epidemiology, The University of North Carolina, Chapel Hill, NC
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42
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Nano-Composite Foam Sensor System in Football Helmets. Ann Biomed Eng 2017; 45:2742-2749. [DOI: 10.1007/s10439-017-1910-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/27/2017] [Indexed: 10/18/2022]
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43
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Kuo C, Wu L, Zhao W, Fanton M, Ji S, Camarillo DB. Propagation of errors from skull kinematic measurements to finite element tissue responses. Biomech Model Mechanobiol 2017; 17:235-247. [PMID: 28856485 DOI: 10.1007/s10237-017-0957-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/20/2017] [Indexed: 11/24/2022]
Abstract
Real-time quantification of head impacts using wearable sensors is an appealing approach to assess concussion risk. Traditionally, sensors were evaluated for accurately measuring peak resultant skull accelerations and velocities. With growing interest in utilizing model-estimated tissue responses for injury prediction, it is important to evaluate sensor accuracy in estimating tissue response as well. Here, we quantify how sensor kinematic measurement errors can propagate into tissue response errors. Using previous instrumented mouthguard validation datasets, we found that skull kinematic measurement errors in both magnitude and direction lead to errors in tissue response magnitude and distribution. For molar design instrumented mouthguards susceptible to mandible disturbances, 150-400% error in skull kinematic measurements resulted in 100% error in regional peak tissue response. With an improved incisor design mitigating mandible disturbances, errors in skull kinematics were reduced to <50%, and several tissue response errors were reduced to <10%. Applying 30[Formula: see text] rotations to reference kinematic signals to emulate sensor transformation errors yielded below 10% error in regional peak tissue response; however, up to 20% error was observed in peak tissue response for individual finite elements. These findings demonstrate that kinematic resultant errors result in regional peak tissue response errors, while kinematic directionality errors result in tissue response distribution errors. This highlights the need to account for both kinematic magnitude and direction errors and accurately determine transformations between sensors and the skull.
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Affiliation(s)
- Calvin Kuo
- Department of Mechanical Engineering, Stanford University, 443 Via Ortega, Shriram Center Room 202, Stanford, CA, 94305, USA.
| | - Lyndia Wu
- Department of Bio-Engineering, Stanford University, 443 Via Ortega, Shriram Center Room 202, Stanford, CA, 94305, USA
| | - Wei Zhao
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott St, Gateway Park 4004, Worcester, MA, 01605, USA
| | - Michael Fanton
- Department of Mechanical Engineering, Stanford University, 443 Via Ortega, Shriram Center Room 202, Stanford, CA, 94305, USA
| | - Songbai Ji
- Department of Biomedical Engineering, Worcester Polytechnic Institute, 60 Prescott St, Gateway Park 4004, Worcester, MA, 01605, USA
| | - David B Camarillo
- Department of Mechanical Engineering, Stanford University, 443 Via Ortega, Shriram Center Room 202, Stanford, CA, 94305, USA.,Department of Bio-Engineering, Stanford University, 443 Via Ortega, Shriram Center Room 202, Stanford, CA, 94305, USA
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44
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Yuan W, Leach J, Maloney T, Altaye M, Smith D, Gubanich PJ, Barber Foss KD, Thomas S, DiCesare CA, Kiefer AW, Myer GD. Neck Collar with Mild Jugular Vein Compression Ameliorates Brain Activation Changes during a Working Memory Task after a Season of High School Football. J Neurotrauma 2017; 34:2432-2444. [DOI: 10.1089/neu.2016.4834] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Weihong Yuan
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - James Leach
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Thomas Maloney
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - David Smith
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Paul J. Gubanich
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Kim D. Barber Foss
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Division of Health Sciences, Department of Athletic Training, Mount St. Joseph University, Cincinnati, Ohio
- Rocky Mountain University of Health Professions, Provo, Utah
| | - Staci Thomas
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Christopher A. DiCesare
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Adam W. Kiefer
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Center for Cognition, Action and Perception, Department of Psychology, University of Cincinnati, Cincinnati, Ohio
| | - Gregory D. Myer
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio
- The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
- Department of Orthopaedics, University of Pennsylvania, Philadelphia, Pennsylvania
- The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts
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45
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Cortes N, Lincoln AE, Myer GD, Hepburn L, Higgins M, Putukian M, Caswell SV. Video Analysis Verification of Head Impact Events Measured by Wearable Sensors. Am J Sports Med 2017; 45:2379-2387. [PMID: 28541813 DOI: 10.1177/0363546517706703] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Wearable sensors are increasingly used to quantify the frequency and magnitude of head impact events in multiple sports. There is a paucity of evidence that verifies head impact events recorded by wearable sensors. PURPOSE To utilize video analysis to verify head impact events recorded by wearable sensors and describe the respective frequency and magnitude. STUDY DESIGN Cohort study (diagnosis); Level of evidence, 2. METHODS Thirty male (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.06 m; mean weight, 73.4 ± 12.2 kg) and 35 female (mean age, 16.2 ± 1.3 years; mean height, 1.66 ± 0.05 m; mean weight, 61.2 ± 6.4 kg) players volunteered to participate in this study during the 2014 and 2015 lacrosse seasons. Participants were instrumented with GForceTracker (GFT; boys) and X-Patch sensors (girls). Simultaneous game video was recorded by a trained videographer using a single camera located at the highest midfield location. One-third of the field was framed and panned to follow the ball during games. Videographic and accelerometer data were time synchronized. Head impact counts were compared with video recordings and were deemed valid if (1) the linear acceleration was ≥20 g, (2) the player was identified on the field, (3) the player was in camera view, and (4) the head impact mechanism could be clearly identified. Descriptive statistics of peak linear acceleration (PLA) and peak rotational velocity (PRV) for all verified head impacts ≥20 g were calculated. RESULTS For the boys, a total recorded 1063 impacts (2014: n = 545; 2015: n = 518) were logged by the GFT between game start and end times (mean PLA, 46 ± 31 g; mean PRV, 1093 ± 661 deg/s) during 368 player-games. Of these impacts, 690 were verified via video analysis (65%; mean PLA, 48 ± 34 g; mean PRV, 1242 ± 617 deg/s). The X-Patch sensors, worn by the girls, recorded a total 180 impacts during the course of the games, and 58 (2014: n = 33; 2015: n = 25) were verified via video analysis (32%; mean PLA, 39 ± 21 g; mean PRV, 1664 ± 619 rad/s). CONCLUSION The current data indicate that existing wearable sensor technologies may substantially overestimate head impact events. Further, while the wearable sensors always estimated a head impact location, only 48% of the impacts were a result of direct contact to the head as characterized on video. Using wearable sensors and video to verify head impacts may decrease the inclusion of false-positive impacts during game activity in the analysis.
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Affiliation(s)
- Nelson Cortes
- Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia, USA
| | | | - Gregory D Myer
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Lisa Hepburn
- MedStar Health Research Institute, Baltimore, Maryland, USA
| | | | | | - Shane V Caswell
- Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Manassas, Virginia, USA
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Kindschi K, Higgins M, Hillman A, Penczek G, Lincoln A. Video analysis of high-magnitude head impacts in men's collegiate lacrosse. BMJ Open Sport Exerc Med 2017; 3:e000165. [PMID: 29259805 PMCID: PMC5731229 DOI: 10.1136/bmjsem-2016-000165] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2017] [Indexed: 11/29/2022] Open
Abstract
Background/aim Lacrosse is one of the fastest growing sports in the USA. Efforts to minimise head injuries focus on promoting safe play through player and coach education, rules enforcement and use of effective protective equipment. The study aims to determine event characteristics of high-magnitude head impacts in men’s collegiate lacrosse competitions through video analysis. Methods Seventeen Division I men’s collegiate lacrosse players wore instrumented helmets that collected biomechanical measures of head impacts. During 15 competitions, the magnitude of linear acceleration, rotational velocity and helmet impact location were recorded. Impacts with linear accelerations above a 70 g threshold were correlated with video to confirm impact location and to determine event characteristics—source of impact and player activity at the time of impact. Results A total of 122 high-magnitude impacts were reviewed on video. Player-to-player contact (n=94, 77.0%) was the most common impact mechanism, followed by stick-to-player contact (n=11, 9.0%). Impacts occurred most often when the athlete was delivering a body check (n=39, 32.0%), fighting for loose ball possession (n=35, 28.7%) or attacking the goal (n=35, 28.7%). The most frequent impact locations were the front of the helmet (n=46, 37.8%) and the left side of the helmet (n=26, 21.3%). Conclusions In men’s collegiate lacrosse games, the majority of high-magnitude head impacts resulted from player-to-player contact when the sensored athlete did not have possession of the ball. Video analysis provides the game context for head impact mechanisms, which is critical to developing sport-specific injury prevention strategies.
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Affiliation(s)
- Kari Kindschi
- Department of Sports Medicine, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
| | | | - Andrea Hillman
- Kinesiology Department, Towson University, Towson, Maryland, USA
| | - Gregory Penczek
- Kinesiology Department, Towson University, Towson, Maryland, USA
| | - Andrew Lincoln
- Department of Sports Medicine, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
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47
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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: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Miyashita TL, Diakogeorgiou E, Marrie K. Correlation of Head Impacts to Change in Balance Error Scoring System Scores in Division I Men's Lacrosse Players. Sports Health 2017; 9:318-323. [PMID: 28060567 PMCID: PMC5496699 DOI: 10.1177/1941738116685306] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Investigation into the effect of cumulative subconcussive head impacts has yielded various results in the literature, with many supporting a link to neurological deficits. Little research has been conducted on men's lacrosse and associated balance deficits from head impacts. HYPOTHESES (1) Athletes will commit more errors on the postseason Balance Error Scoring System (BESS) test. (2) There will be a positive correlation to change in BESS scores and head impact exposure data. STUDY DESIGN Prospective longitudinal study. LEVEL OF EVIDENCE Level 3. METHODS Thirty-four Division I men's lacrosse players (age, 19.59 ± 1.42 years) wore helmets instrumented with a sensor to collect head impact exposure data over the course of a competitive season. Players completed a BESS test at the start and end of the competitive season. RESULTS The number of errors from pre- to postseason increased during the double-leg stance on foam ( P < 0.001), tandem stance on foam ( P = 0.009), total number of errors on a firm surface ( P = 0.042), and total number of errors on a foam surface ( P = 0.007). There were significant correlations only between the total errors on a foam surface and linear acceleration ( P = 0.038, r = 0.36), head injury criteria ( P = 0.024, r = 0.39), and Gadd Severity Index scores ( P = 0.031, r = 0.37). CONCLUSION Changes in the total number of errors on a foam surface may be considered a sensitive measure to detect balance deficits associated with cumulative subconcussive head impacts sustained over the course of 1 lacrosse season, as measured by average linear acceleration, head injury criteria, and Gadd Severity Index scores. If there is microtrauma to the vestibular system due to repetitive subconcussive impacts, only an assessment that highly stresses the vestibular system may be able to detect these changes. CLINICAL RELEVANCE Cumulative subconcussive impacts may result in neurocognitive dysfunction, including balance deficits, which are associated with an increased risk for injury. The development of a strategy to reduce total number of head impacts may curb the associated sequelae. Incorporation of a modified BESS test, firm surface only, may not be recommended as it may not detect changes due to repetitive impacts over the course of a competitive season.
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49
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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: 5.3] [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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50
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Myer GD, Yuan W, Barber Foss KD, Thomas S, Smith D, Leach J, Kiefer AW, Dicesare C, Adams J, Gubanich PJ, Kitchen K, Schneider DK, Braswell D, Krueger D, Altaye M. Analysis of head impact exposure and brain microstructure response in a season-long application of a jugular vein compression collar: a prospective, neuroimaging investigation in American football. Br J Sports Med 2016; 50:1276-1285. [PMID: 27307271 PMCID: PMC5099231 DOI: 10.1136/bjsports-2016-096134] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2016] [Indexed: 01/03/2023]
Abstract
Background Historical approaches to protect the brain from outside the skull (eg, helmets and mouthpieces) have been ineffective in reducing internal injury to the brain that arises from energy absorption during sports-related collisions. We aimed to evaluate the effects of a neck collar, which applies gentle bilateral jugular vein compression, resulting in cerebral venous engorgement to reduce head impact energy absorption during collision. Specifically, we investigated the effect of collar wearing during head impact exposure on brain microstructure integrity following a competitive high school American football season. Methods A prospective longitudinal controlled trial was employed to evaluate the effects of collar wearing (n=32) relative to controls (CTRL; n=30) during one competitive football season (age: 17.04±0.67 years). Impact exposure was collected using helmet sensors and white matter (WM) integrity was quantified based on diffusion tensor imaging (DTI) serving as the primary outcome. Results With similar overall g-forces and total head impact exposure experienced in the two study groups during the season (p>0.05), significant preseason to postseason changes in mean diffusivity, axial diffusivity and radial diffusivity in the WM integrity were noted in the CTRL group (corrected p<0.05) but not in the collar group (p>0.05). The CTRL group demonstrated significantly larger preseason to postseason DTI change in multiple WM regions compared with the collar group (corrected p<0.05). Discussion Reduced WM diffusivity alteration was noted in participants wearing a neck collar after a season of competitive football. Collar wearing may have provided a protective effect against brain microstructural changes after repetitive head impacts. Trial registration number NCT02696200.
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Affiliation(s)
- Gregory D Myer
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA Department of Orthopaedics, University of Pennsylvania, Philadelphia, Pennsylvania, USA The Micheli Center for Sports Injury Prevention, Waltham, Massachusetts, USA Department of Orthopaedic Surgery, University of Cincinnati, Cincinnati, Ohio, USA
| | - Weihong Yuan
- Pediatric Neuroimaging Research Consortium, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Kim D Barber Foss
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Health Sciences, Department of Athletic Training, Mount St. Joseph University, Cincinnati, Ohio, USA Rocky Mountain University of Health Professions, Provo, Utah, USA
| | - Staci Thomas
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - David Smith
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - James Leach
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Adam W Kiefer
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA Department of Psychology, Center for Cognition, Action and Perception, University of Cincinnati, Cincinnati, Ohio, USA
| | - Chris Dicesare
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Janet Adams
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul J Gubanich
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA
| | - Katie Kitchen
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Daniel K Schneider
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Daniel Braswell
- Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Division of Sports Medicine, The SPORT Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Darcy Krueger
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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