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Meier TB, Giraldo-Chica M, España LY, Mayer AR, Harezlak J, Nencka AS, Wang Y, Koch KM, Wu YC, Saykin AJ, Giza CC, Goldman J, DiFiori JP, Guskiewicz KM, Mihalik JP, Brooks A, Broglio SP, McAllister T, McCrea MA. Resting-State fMRI Metrics in Acute Sport-Related Concussion and Their Association with Clinical Recovery: A Study from the NCAA-DOD CARE Consortium. J Neurotrauma 2019; 37:152-162. [PMID: 31407610 DOI: 10.1089/neu.2019.6471] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
There has been a recent call for longitudinal cohort studies to track the physiological recovery of sport-related concussion (SRC) and its relationship with clinical recovery. Resting-state functional magnetic resonance imaging (rs-fMRI) has shown potential for detecting subtle changes in brain function after SRC. We investigated the effects of SRC on rs-fMRI metrics assessing local connectivity (regional homogeneity; REHO), global connectivity (average nodal strength), and the relative amplitude of slow oscillations of rs-fMRI (fractional amplitude of low-frequency fluctuations; fALFF). Athletes diagnosed with SRC (n = 92) completed visits with neuroimaging at 24-48 h post-injury (24 h), after clearance to begin the return-to-play (RTP) progression (asymptomatic), and 7 days following unrestricted RTP (post-RTP). Non-injured athletes (n = 82) completed visits yoked to the schedule of matched injured athletes and served as controls. Concussed athletes had elevated symptoms, worse neurocognitive performance, greater balance deficits, and elevated psychological symptoms at the 24-h visit relative to controls. These deficits were largely recovered by the asymptomatic visit. Concussed athletes still reported elevated psychological symptoms at the asymptomatic visit relative to controls. Concussed athletes also had elevated REHO in the right middle and superior frontal gyri at the 24-h visit that returned to normal levels by the asymptomatic visit. Additionally, REHO in these regions at 24 h predicted psychological symptoms at the asymptomatic visit in concussed athletes. Current results suggest that SRC is associated with an acute alteration in local connectivity that follows a similar time course as clinical recovery. Our results do not indicate strong evidence that concussion-related alterations in rs-fMRI persist beyond clinical recovery.
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Brett BL, Wu Y, Mustafi SM, Harezlak J, Giza CC, DiFiori JP, Guskiewicz KM, Mihalik JP, McAllister TW, Broglio SP, McCrea MA, Meier TB. White Matter Abnormalities on Diffusion Tensor Imaging Following Recovery from Sport-Related Concussion and Risk of Subsequent Re-injury. Arch Clin Neuropsychol 2019. [DOI: 10.1093/arclin/acz026.06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Purpose
A recent systematic review determined that the physiological effects of concussion may persist beyond clinical recovery. Preclinical models suggest that these physiological effects are accompanied by a window of cerebral vulnerability that is associated with risk for subsequent, more severe injury. This study examined the association between persistent diffusion tensor imaging signal following clinical recovery of sport-related concussion and risk of re-injury.
Methods
Average mean diffusivity (MD) was obtained in a region-of-interest (ROI) in which concussed athletes showed significantly elevated MD acutely after injury (<48 hours), at an asymptomatic timepoint, 7-days post-return to play, and 6 months post-injury relative to controls. The relationship between MD in the identified ROI and risk of sustaining a subsequent concussion over a 1-year period was examined with a binary logistic regression (re-injured, yes/no).
Results
Eleven of 83 concussed athletes suffered a second concussion within a 1-year period. The relationship between MD at 7-days post return to play and risk of sustaining a secondary injury within 1-year showed a non-significant trend (X2(1)=4.17, p=.057, B=0.03, SE=0.017; Nagelkerke R2=0.16). Mean differences in MD between the repeat injury and non-reinjured group at 7-days post return to play produced a large effect, d=.75. MD in the a priori ROI at the other recovery time points did not predict elevated risk of re-injury.
Conclusion
These preliminary findings suggest that a large effect size was present in the relationship between persistent diffusion signal abnormalities and risk for subsequent re-injury. This provides support for a window of cerebral vulnerability following concussion, though further examination is needed.
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Rowson S, Campolettano ET, Duma SM, Stemper B, Shah A, Harezlak J, Riggen L, Mihalik JP, Guskiewicz KM, Giza C, Brooks A, Cameron K, McAllister T, Broglio SP, McCrea M. Accounting for Variance in Concussion Tolerance Between Individuals: Comparing Head Accelerations Between Concussed and Physically Matched Control Subjects. Ann Biomed Eng 2019; 47:2048-2056. [PMID: 31342336 PMCID: PMC6785592 DOI: 10.1007/s10439-019-02329-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/17/2019] [Indexed: 11/22/2022]
Abstract
Researchers have been collecting head impact data from instrumented football players to characterize the biomechanics of concussion for the past 15 years, yet the link between biomechanical input and clinical outcome is still not well understood. We have previously shown that even though concussive biomechanics might be unremarkable in large datasets of head impacts, the impacts causing injury are of high magnitude for the concussed individuals relative to their impact history. This finding suggests a need to account for differences in tolerance at the individual level. In this study, we identified control subjects for our concussed subjects who demonstrated traits we believed were correlated to factors thought to affect injury tolerance, including height, mass, age, race, and concussion history. A total of 502 college football players were instrumented with helmet-mounted accelerometer arrays and provided complete baseline assessment data, 44 of which sustained a total of 49 concussion. Biomechanical measures quantifying impact frequency and acceleration magnitude were compared between groups. On average, we found that concussed subjects experienced 93.8 more head impacts (p = 0.0031), 10.2 more high magnitude impacts (p = 0.0157), and 1.9 × greater risk-weighted exposure (p = 0.0175) than their physically matched controls. This finding provides further evidence that head impact data need to be considered at the individual level and that cohort wide assessments may be of little value in the context of concussion.
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Swartz EE, Myers JL, Cook SB, Guskiewicz KM, Ferrara MS, Cantu RC, Chang H, Broglio SP. A helmetless-tackling intervention in American football for decreasing head impact exposure: A randomized controlled trial. J Sci Med Sport 2019; 22:1102-1107. [PMID: 31204104 DOI: 10.1016/j.jsams.2019.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 04/01/2019] [Accepted: 05/30/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To evaluate a behavioral intervention to reduce head impact exposure in youth playing American football. DESIGN Nested randomized controlled trial. METHODS Participants, ages 14-17 years, wore head impact sensors (SIM-G™) during two seasons of play. Those randomized to the intervention group underwent weekly tackling/blocking drills performed without helmets (WoH) and shoulder pads while the control group trained as normal, matching frequency and duration. Research personnel provided daily oversight to maintain fidelity. Head impact frequency (≥10g) per athlete exposure (ImpAE) was analyzed over time (two 11-week seasons) using mixed effect models or ANCOVA. Secondary outcomes included exposure-type (training, game) and participation level (entry-level versus upper-level secondary education). RESULTS One-hundred fifteen participants (59 WoH, 56 control) met compliance criteria, contributing 47,382 head impacts and 10,751 athlete exposures for analysis. WoH had fewer ImpAE during games compared to control participants at weeks 4 (p=0.0001 season 1, p=0.0005 season 2) and 7 (p=0.0001 both seasons). Upper-level WoH participants had less ImpAE during games than their matched controls at weeks 4 (p=0.017 and p=0.026) and 7 (p=0.037 and p=0.014) in both seasons, respectively. Upper-level WoH also had fewer ImpAE during training at week 7 (p=0.015) in season one. CONCLUSIONS Tackling and blocking drills performed without a helmet during training reduced the frequency of head impacts during play, especially during games. However, these differences disappeared by the end of the season. Future research should explore the frequency of behavioral intervention and a dose-response relationship considering years of player experience. TRIAL REGISTRATION ClinicalTrials.gov # NCT02519478.
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Northam WT, Cools MJ, Boyd M, Mihalik JP, Guskiewicz KM, Carneiro KA. Evaluating Acute Sport-related Concussion In The Primary Care Setting: Are We Dropping The Ball? Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000562709.36183.5f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lynall RC, Blackburn JT, Guskiewicz KM, Marshall SW, Plummer P, Mihalik JP. Functional balance assessment in recreational college-aged individuals with a concussion history. J Sci Med Sport 2019; 22:503-508. [DOI: 10.1016/j.jsams.2018.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/25/2018] [Accepted: 10/21/2018] [Indexed: 10/27/2022]
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McCrea M, Broglio S, McAllister T, Zhou W, Zhao S, Katz B, Kudela M, Harezlak J, Nelson L, Meier T, Marshall SW, Guskiewicz KM. Return to play and risk of repeat concussion in collegiate football players: comparative analysis from the NCAA Concussion Study (1999-2001) and CARE Consortium (2014-2017). Br J Sports Med 2019; 54:102-109. [PMID: 31036562 DOI: 10.1136/bjsports-2019-100579] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 01/04/2023]
Abstract
OBJECTIVE We compared data from the National Collegiate Athletic Association (NCAA) Concussion Study (1999-2001) and the NCAA-Department of Defense Concussion Assessment, Research and Education (CARE) Consortium (2014-2017) to examine how clinical management, return to play (RTP) and risk of repeat concussion in collegiate football players have changed over the past 15 years. METHODS We analysed data on reported duration of symptoms, symptom-free waiting period (SFWP), RTP and occurrence of within-season repeat concussion in collegiate football players with diagnosed concussion from the NCAA Study (n=184) and CARE (n=701). RESULTS CARE athletes had significantly longer symptom duration (CARE median=5.92 days, IQR=3.02-9.98 days; NCAA median=2.00 days, IQR=1.00-4.00 days), SFWP (CARE median=6.00 days, IQR=3.49-9.00 days; NCAA median=0.98 days, IQR=0.00-4.00 days) and RTP (CARE median=12.23 days, IQR=8.04-18.92 days; NCAA median=3.00 days, IQR=1.00-8.00 days) than NCAA Study athletes (all p<0.0001). In CARE, there was only one case of repeat concussion within 10 days of initial injury (3.7% of within-season repeat concussions), whereas 92% of repeat concussions occurred within 10 days in the NCAA Study (p<0.001). The average interval between first and repeat concussion in CARE was 56.41 days, compared with 5.59 days in the NCAA Study (M difference=50.82 days; 95% CI 38.37 to 63.27; p<0.0001). CONCLUSION Our findings indicate that concussion in collegiate football is managed more conservatively than 15 years ago. These changes in clinical management appear to have reduced the risk of repetitive concussion during the critical period of cerebral vulnerability after sport-related concussion (SRC). These data support international guidelines recommending additional time for brain recovery before athletes RTP after SRC.
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Klein AP, Tetzlaff JE, Bonis JM, Nelson LD, Mayer AR, Huber DL, Harezlak J, Mathews VP, Ulmer JL, Sinson GP, Nencka AS, Koch KM, Wu YC, Saykin AJ, DiFiori JP, Giza CC, Goldman J, Guskiewicz KM, Mihalik JP, Duma SM, Rowson S, Brooks A, Broglio SP, McAllister T, McCrea MA, Meier TB. Prevalence of Potentially Clinically Significant Magnetic Resonance Imaging Findings in Athletes with and without Sport-Related Concussion. J Neurotrauma 2019; 36:1776-1785. [PMID: 30618331 DOI: 10.1089/neu.2018.6055] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Previous studies have shown that mild traumatic brain injury (mTBI) can cause abnormalities in clinically relevant magnetic resonance imaging (MRI) sequences. No large-scale study, however, has prospectively assessed this in athletes with sport-related concussion (SRC). The aim of the current study was to characterize and compare the prevalence of acute, trauma-related MRI findings and clinically significant, non-specific MRI findings in athletes with and without SRC. College and high-school athletes were prospectively enrolled and participated in scanning sessions between January 2015 through August 2017. Concussed contact sport athletes (n = 138; 14 female [F]; 19.5 ± 1.6 years) completed up to four scanning sessions after SRC. Non-concussed contact (n = 135; 15 F; 19.7 ± 1.6) and non-contact athletes (n = 96; 15 F; 20.0 ± 1.7) completed similar scanning sessions and served as controls. Board-certified neuroradiologists, blinded to SRC status, reviewed T1-weighted and T2-weighted fluid-attenuated inversion recovery and T2*-weighted and T2-weighted images for acute (i.e., injury-related) or non-acute findings that prompted recommendation for clinical follow-up. Concussed athletes were more likely to have MRI findings relative to contact (30.4% vs. 15.6%; odds ratio [OR] = 2.32; p = 0.01) and non-contact control athletes (19.8%; OR = 2.11; p = 0.04). Female athletes were more likely to have MRI findings than males (43.2% vs. 19.4%; OR = 2.62; p = 0.01). One athlete with SRC had an acute, injury-related finding; group differences were largely driven by increased rate of non-specific white matter hyperintensities in concussed athletes. This prospective, large-scale study demonstrates that <1% of SRCs are associated with acute injury findings on qualitative structural MRI, providing empirical support for clinical guidelines that do not recommend use of MRI after SRC.
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Dompier TP, Kucera KL, Drezner JA, Casa DJ, Register-Mihalik JK, Guskiewicz KM. Sudden Death and Catastrophic Injury Reporting: A Call to Action for Athletic Trainers. J Athl Train 2019; 54:122-123. [PMID: 30668135 DOI: 10.4085/1062-6050-77-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Register-Mihalik JK, Sarmiento K, Vander Vegt CB, Guskiewicz KM. Considerations for Athletic Trainers: A Review of Guidance on Mild Traumatic Brain Injury Among Children From the Centers for Disease Control and Prevention and the National Athletic Trainers' Association. J Athl Train 2019; 54:12-20. [PMID: 30608870 DOI: 10.4085/1062-6050-451-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Centers for Disease Control and Prevention recently published an evidence-based guideline, "Diagnosis and Management of Mild Traumatic Brain Injury (mTBI) Among Children." The guideline has many applications for athletic trainers. The following commentary provides considerations for athletic trainers regarding the guideline in conjunction with the current National Athletic Trainers' Association position statement "Management of Sport Concussion" and the "Consensus Statement on Concussion in Sport-The 5th International Conference on Concussion in Sport Held in Berlin, October 2016."
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Teel EF, Register-Mihalik JK, Appelbaum LG, Battaglini CL, Carneiro KA, Guskiewicz KM, Marshall SW, Mihalik JP. Randomized Controlled Trial Evaluating Aerobic Training and Common Sport-Related Concussion Outcomes in Healthy Participants. J Athl Train 2018; 53:1156-1165. [PMID: 30562056 DOI: 10.4085/1062-6050-7-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Aerobic exercise interventions are increasingly being prescribed for concussion rehabilitation, but whether aerobic training protocols influence clinical concussion diagnosis and management assessments is unknown. OBJECTIVE To investigate the effects of a brief aerobic exercise intervention on clinical concussion outcomes in healthy, active participants. DESIGN Randomized controlled clinical trial. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Healthy (uninjured) participants (n = 40) who exercised ≥3 times/week. INTERVENTION(S) Participants were randomized into the acute concussion therapy intervention (ACTIVE) training or nontraining group. All participants completed symptom, cognitive, balance, and vision assessments during 2 test sessions approximately 14 days apart. Participants randomized to ACTIVE training completed six 30-minute exercise sessions that progressed from 60% to 80% of individualized maximal oxygen consumption (V˙o2max) across test sessions, while the nontraining group received no intervention. MAIN OUTCOME MEASURE(S) The CNS Vital Signs standardized scores, Vestibular/Ocular Motor Screening near-point convergence distance (cm), and Graded Symptom Checklist, Balance Error Scoring System, and Standardized Assessment of Concussion total scores. RESULTS An interaction effect was found for total symptom score ( P = .01); the intervention group had improved symptom scores between sessions (session 1: 5.1 ± 5.8; session 2: 1.9 ± 3.6). Cognitive flexibility, executive functioning, reasoning, and total symptom score outcomes were better but composite memory, verbal memory, and near-point convergence distance scores were worse at the second session (all P values < .05). However, few changes exceeded the 80% reliable change indices calculated for this study, and effect sizes were generally small to negligible. CONCLUSIONS A brief aerobic training protocol had few meaningful effects on clinical concussion assessment in healthy participants, suggesting that current concussion-diagnostic and -assessment tools remain clinically stable in response to aerobic exercise training. This provides normative data for future researchers, who should further evaluate the effect of ACTIVE training on clinical outcomes among concussed populations. TRIAL REGISTRATION NUMBER ClinicalTrials.gov : NCT02872480.
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Stemper BD, Shah AS, Harezlak J, Rowson S, Mihalik JP, Duma SM, Riggen LD, Brooks A, Cameron KL, Campbell D, DiFiori JP, Giza CC, Guskiewicz KM, Jackson J, McGinty GT, Svoboda SJ, McAllister TW, Broglio SP, McCrea M. Comparison of Head Impact Exposure Between Concussed Football Athletes and Matched Controls: Evidence for a Possible Second Mechanism of Sport-Related Concussion. Ann Biomed Eng 2018; 47:2057-2072. [PMID: 30362082 PMCID: PMC6785644 DOI: 10.1007/s10439-018-02136-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/18/2018] [Indexed: 12/14/2022]
Abstract
Studies of football athletes have implicated repetitive head impact exposure in the onset of cognitive and brain structural changes, even in the absence of diagnosed concussion. Those studies imply accumulating damage from successive head impacts reduces tolerance and increases risk for concussion. Support for this premise is that biomechanics of head impacts resulting in concussion are often not remarkable when compared to impacts sustained by athletes without diagnosed concussion. Accordingly, this analysis quantified repetitive head impact exposure in a cohort of 50 concussed NCAA Division I FBS college football athletes compared to controls that were matched for team and position group. The analysis quantified the number of head impacts and risk weighted exposure both on the day of injury and for the season to the date of injury. 43% of concussed athletes had the most severe head impact exposure on the day of injury compared to their matched control group and 46% of concussed athletes had the most severe head impact exposure for the season to the date of injury compared to their matched control group. When accounting for date of injury or season to date of injury, 72% of all concussed athletes had the most or second most severe head impact exposure compared to their matched control group. These trends associating cumulative head impact exposure with concussion onset were stronger for athletes that participated in a greater number of contact activities. For example, 77% of athletes that participated in ten or more days of contact activities had greater head impact exposure than their matched control group. This unique analysis provided further evidence for the role of repetitive head impact exposure as a predisposing factor for the onset of concussion. The clinical implication of these findings supports contemporary trends of limiting head impact exposure for college football athletes during practice activities in an effort to also reduce risk of concussive injury.
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Vander Vegt CB, Register-Mihalik JK, Ford CB, Rodrigo CJ, Guskiewicz KM, Mihalik JP. Baseline Concussion Clinical Measures Are Related to Sensory Organization and Balance. Med Sci Sports Exerc 2018; 51:264-270. [PMID: 30239494 DOI: 10.1249/mss.0000000000001789] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to examine relationships among baseline demographics, symptom severity, computerized neurocognitive outcomes, and balance performance in collegiate athletes. METHODS Collegiate varsity athletes (N = 207, age = 19.3 ± 1.0 yr) participating in an ongoing clinical research program who completed concussion baseline assessments including a demographic questionnaire, a graded symptom checklist, a neurocognitive assessment, and the Sensory Organization Test (SOT) were included in this study. The SOT composite equilibrium score (COMP) and three sensory ratio scores-vestibular (VEST), visual (VIS), and somatosensory (SOM)-were used to describe athletes' overall sensory organization and ability to use input from each sensory system to maintain balance. Separate stepwise multiple linear regression models were performed for each SOT outcome. Total symptom severity level and CNS Vital Signs domain scores served as predictor variables. RESULTS Stepwise regression models for COMP (R = 0.18, F4,201 = 11.29, P < 0.001), VEST (R = 0.14, F4,201 = 8.16, P < 0.001), and VIS (R = 0.10, F4,201 = 5.52, P < 0.001) were all significant. Faster reaction times and higher executive function scores were associated with higher COMP and VEST scores in separate models. Those with faster reaction times also had significantly higher VIS scores. CONCLUSION Reaction time and executive function demonstrated significant relationships with SOT balance performance. These cognitive processes may influence athletes' ability to organize and process higher-order information and generate appropriate responses to changes in their environment, with respect to balance and injury risk. Future investigations should consider these relationships after injury, and clinicians should be mindful of this relationship when considering concussion management strategies.
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Register-Mihalik JK, Williams RM, Marshall SW, Linnan LA, Mihalik JP, Guskiewicz KM, McLeod TCV. Demographic, Parental, and Personal Factors and Youth Athletes' Concussion-Related Knowledge and Beliefs. J Athl Train 2018; 53:768-775. [PMID: 30198745 DOI: 10.4085/1062-6050-223-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT: Currently, significant attention is focused on improving care for patients with concussions through legislative mandates that include educational interventions. Few researchers have examined young athletes' concussion knowledge and the factors that may influence their knowledge. OBJECTIVE: To use the socioecological model to examine demographic, parental, and personal factors associated with youth athletes' knowledge of concussion. Our ultimate goal is to inform the planning and implementation of youth sport concussion-related interventions. DESIGN: Cross-sectional survey. SETTING: Gymnasium and classroom. PATIENTS OR OTHER PARTICIPANTS: North Carolina and Arizona youth athletes (n = 225; age = 8 to 15 years) active in football, boys' or girls' soccer, boys' or girls' ice hockey, or boys' or girls' lacrosse in 2012-2013. MAIN OUTCOME MEASURE(S): Participants completed a validated, self-administered survey. The intention and belief measures were guided by the theory of planned behavior. Perceptions of concussion and intention to seek care were examined using descriptive statistics. Athletes' concussion knowledge was modeled using linear regressions and generalized estimating equations, with child demographic and personal factors and parental knowledge and attitudes about concussion as predictors. RESULTS: Geography, sport, parental attitudes toward concussion, and athlete age were associated with athlete knowledge in the univariable analyses ( P < .10). In the multivariable model, geographic location (North Carolina versus Arizona, mean difference [MD] = 2.2, 95% confidence interval [CI] = 1.1, 3.2), sport (girls' soccer versus girls' lacrosse, MD = 2.2, 95% CI = 0.7, 3.6), more favorable parental attitudes toward concussion (MD = 1.2 for a 2-standard deviation shift; 95% CI = 0.3, 2.1), and older age (>12 years, MD = 1.6; 95% CI = 0.5, 2.6) were associated with better knowledge about concussion. CONCLUSIONS: Geographic location, sport, parental attitudes about concussion, and athlete's age influenced athletes' concussion-related perceptions, indicating the need to address multiple levels of the socioecological model when targeting youth sport interventions. Parental interventions that translate to an improved culture of youth sport by improving youth athletes' perceptions and experiences are key areas for future work.
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Mustafi SM, Harezlak J, Koch KM, Nencka AS, Meier TB, West JD, Giza CC, DiFiori JP, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio SP, Saykin AJ, McCrea M, McAllister TW, Wu YC. Acute White-Matter Abnormalities in Sports-Related Concussion: A Diffusion Tensor Imaging Study from the NCAA-DoD CARE Consortium. J Neurotrauma 2018; 35:2653-2664. [PMID: 29065805 DOI: 10.1089/neu.2017.5158] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sports-related concussion (SRC) is an important public health issue. Although standardized assessment tools are useful in the clinical management of acute concussion, the underlying pathophysiology of SRC and the time course of physiological recovery after injury remain unclear. In this study, we used diffusion tensor imaging (DTI) to detect white matter alterations in football players within 48 h after SRC. As part of the NCAA-DoD CARE Consortium study of SRC, 30 American football players diagnosed with acute concussion and 28 matched controls received clinical assessments and underwent advanced magnetic resonance imaging scans. To avoid selection bias and partial volume effects, whole-brain skeletonized white matter was examined by tract-based spatial statistics to investigate between-group differences in DTI metrics and their associations with clinical outcome measures. Mean diffusivity was significantly higher in brain white matter of concussed athletes, particularly in frontal and subfrontal long white matter tracts. In the concussed group, axial diffusivity was significantly correlated with the Brief Symptom Inventory and there was a similar trend with the symptom severity score of the Sport Concussion Assessment Tool. In addition, concussed athletes with higher fractional anisotropy performed better on the cognitive component of the Standardized Assessment of Concussion. Overall, the results of this study are consistent with the hypothesis that SRC is associated with changes in white matter tracts shortly after injury, and these differences are correlated clinically with acute symptoms and functional impairments.
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Nencka AS, Meier TB, Wang Y, Muftuler LT, Wu YC, Saykin AJ, Harezlak J, Brooks MA, Giza CC, Difiori J, Guskiewicz KM, Mihalik JP, LaConte SM, Duma SM, Broglio S, McAllister T, McCrea MA, Koch KM. Stability of MRI metrics in the advanced research core of the NCAA-DoD concussion assessment, research and education (CARE) consortium. Brain Imaging Behav 2018; 12:1121-1140. [PMID: 29064019 PMCID: PMC6445663 DOI: 10.1007/s11682-017-9775-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The NCAA-DoD Concussion Assessment, Research, and Education (CARE) consortium is performing a large-scale, comprehensive study of sport related concussions in college student-athletes and military service academy cadets. The CARE "Advanced Research Core" (ARC), is focused on executing a cutting-edge investigative protocol on a subset of the overall CARE athlete population. Here, we present the details of the CARE ARC MRI acquisition and processing protocol along with preliminary analyzes of within-subject, between-site, and between-subject stability across a variety of MRI biomarkers. Two experimental datasets were utilized for this analysis. First, two "human phantom" subjects were imaged multiple times at each of the four CARE ARC imaging sites, which utilize equipment from two imaging vendors. Additionally, a control cohort of healthy athletes participating in non-contact sports were enrolled in the study at each CARE ARC site and imaged at four time points. Multiple morphological image contrasts were acquired in each MRI exam; along with quantitative diffusion, functional, perfusion, and relaxometry imaging metrics. As expected, the imaging markers were found to have varying levels of stability throughout the brain. Importantly, between-subject variance was generally found to be greater than within-subject and between-site variance. These results lend support to the expectation that cross-site and cross-vendor advanced quantitative MRI metrics can be utilized to improve analytic power in assessing sensitive neurological variations; such as those effects hypothesized to occur in sports-related-concussion. This stability analysis provides a crucial foundation for further work utilizing this expansive dataset, which will ultimately be freely available through the Federal Interagency Traumatic Brain Injury Research Informatics System.
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Kerr ZY, Thomas LC, Simon JE, McCrea M, Guskiewicz KM. Association Between History of Multiple Concussions and Health Outcomes Among Former College Football Players: 15-Year Follow-up From the NCAA Concussion Study (1999-2001). Am J Sports Med 2018; 46:1733-1741. [PMID: 29620911 DOI: 10.1177/0363546518765121] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Previous research has examined associations between concussion history and adverse health outcomes among former professional football players. Less is known about the potential effects of concussion among former college football players without additional exposure at the professional level. PURPOSE To examine the association between concussion and adverse health outcomes in a cohort of former college football players without exposure to professional football, 15 years after their playing careers ended. STUDY DESIGN Cross-sectional study; Level of evidence, 3. METHODS A sample of 204 former collegiate football players (23.4% of eligible athletes with available contact information)-all of whom played at least 1 season of football from 1999 to 2001 in the National Collegiate Athletic Association (NCAA) and had no professional football exposure-completed a general health survey that assessed lifetime concussion history and included the following: the Veterans RAND 36 Item Health Survey, containing a physical composite score (PCS) and mental composite score (MCS); the depression module of the Patient Health Questionnaire; and the 4-item CAGE alcohol dependence questionnaire (for "cutting down, annoyance by criticism, guilty feeling, and eye-openers"). Multivariable binomial regression models estimated adjusted prevalence ratios (PRs) with 95% CIs while controlling for demographics and playing history covariates through forward selection model building. RESULTS Most participants reported a concussion history (84.3%). Overall, 22.1% and 39.2% of participants reported a PCS and an MCS <50, respectively (indicating worse health than the US national average); 19.1% reported Patient Health Questionnaire scores ≥10 (indicating moderate/severe depression); and 24.8% reported CAGE scores ≥2 (indicating alcohol dependence). The prevalence of having an MCS <50 was higher among those reporting ≥3 versus 0 concussions (PR, 2.5; 95% CI, 1.3-4.9). Controlling for body mass index (BMI), the prevalence of moderate/severe depression was higher among those reporting ≥3 versus 0 concussions (PR, 4.2; 95% CI, 1.0-16.3). Controlling for BMI, the prevalence of having a PCS <50 was higher among those reporting ≥3 versus 1 or 2 concussions (PR, 2.6; 95% CI, 1.3-5.0) but not 0 concussions (PR, 1.5; 95% CI, 0.6-3.6). No associations were found for alcohol dependence. CONCLUSION Associations between a history of multiple concussions and adverse health outcomes were found among former collegiate football players without professional football exposure but were limited to those reporting ≥3 prior concussions. Because only 23.4% of eligible athletes responded to the survey, the possibility of ascertainment bias exists, and our findings should thus be interpreted with some caution. Continued examination within nonprofessional football populations is needed, but findings highlight the need for prevention efforts to reduce concussion incidence.
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Register-Mihalik JK, Cameron KL, Linnan LA, Kay MC, Houston MN, Peck KY, Hennink- Kaminski HJ, Svoboda SJ, Gildner P, Kerr ZY, Guskiewicz KM, Marshall SW. Factors Associated with Intention to Disclose Concussive Symptoms among Service Academy Cadets. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538723.96055.a4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vander Vegt CB, Register-Mihalik JK, Kostogiannes VT, Campbell KR, Guskiewicz KM, Mihalik JP. Baseline Visual Measures in High School Football Players With and Without Previous Concussion. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535842.76458.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cabell GH, Teel EF, Hanson ED, Mihalik JP, Guskiewicz KM. The Test-retest Reliability And Exercise-driven Changes Of UCH-L1 In Healthy, Recreationally Active College Students. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538747.81701.2e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kerr ZY, Thomas LC, Simon JE, McCrea M, Guskiewicz KM. Concussion Is Associated With Adverse Health Outcomes. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535091.80647.81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Asken BM, Bauer RM, Guskiewicz KM, McCrea MA, Schmidt JD, Giza CC, Snyder AR, Houck ZM, Kontos AP, McAllister TW, Broglio SP, Clugston JR, Anderson S, Bazarian J, Brooks A, Buckley T, Chrisman S, Collins M, DiFiori J, Duma S, Dykhuizen B, Eckner JT, Feigenbaum L, Hoy A, Kelly L, Langford TD, Lintner L, McGinty G, Mihalik J, Miles C, Ortega J, Port N, Putukian M, Rowson S, Svoboda S. Immediate Removal From Activity After Sport-Related Concussion Is Associated With Shorter Clinical Recovery and Less Severe Symptoms in Collegiate Student-Athletes. Am J Sports Med 2018; 46:1465-1474. [PMID: 29558195 PMCID: PMC6988451 DOI: 10.1177/0363546518757984] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Timely removal from activity after concussion symptoms remains problematic despite heightened awareness. Previous studies indicated potential adverse effects of continuing to participate in physical activity immediately after sustaining a concussion. Hypothesis/Purpose: The purpose was to determine the effect of timing of removal from play after concussion on clinical outcomes. It was hypothesized that immediate removal from activity after sport-related concussion (SRC) would be associated with less time missed from sport, a shorter symptomatic period, and better outcomes on acute clinical measures. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS Data were reported from the National Collegiate Athletic Association and Department of Defense Grand Alliance: Concussion Awareness, Research, and Education (CARE) Consortium. Participants with 506 diagnosed SRCs from 18 sports and 25 institutions and military service academies were analyzed and classified as either immediate removal from activity (I-RFA) or delayed removal from activity (D-RFA). Outcomes of interest included time missed from sport attributed to their SRC, symptom duration, and clinical assessment scores. RESULTS There were 322 participants (63.6%) characterized as D-RFA. I-RFA status was associated with significantly less time missed from sport ( R2 change = .022-.024, P < .001 to P = .001) and shorter symptom duration ( R2 change = .044-.046, P < .001 [all imputations]) while controlling for other SRC recovery modifiers. These athletes missed approximately 3 fewer days from sport participation. I-RFA athletes had significantly less severe acute SRC symptoms and were at lower risk of recovery taking ≥14 days (relative risk = .614, P < .001, small-medium effect size) and ≥21 days (relative risk = .534, P = .010, small effect size). CONCLUSION I-RFA is a protective factor associated with less severe acute symptoms and shorter recovery after SRC. Conveying this message to athletes, coaches, and others involved in the care of athletes may promote timely injury reporting.
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Clark MD, Varangis EML, Champagne AA, Giovanello KS, Shi F, Kerr ZY, Smith JK, Guskiewicz KM. Effects of Career Duration, Concussion History, and Playing Position on White Matter Microstructure and Functional Neural Recruitment in Former College and Professional Football Athletes. Radiology 2018; 286:967-977. [PMID: 29087238 PMCID: PMC5834225 DOI: 10.1148/radiol.2017170539] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Purpose To better understand the relationship between exposure to concussive and subconcussive head impacts, white matter integrity, and functional task-related neural activity in former U.S. football athletes. Materials and Methods Between 2011 and 2013, 61 cognitively unimpaired former collegiate and professional football players (age range, 52-65 years) provided informed consent to participate in this cross-sectional study. Participants were stratified across three crossed factors: career duration, concussion history, and primary playing position. Fractional anisotropy (FA) and blood oxygen level-dependent (BOLD) percent signal change (PSC) were measured with diffusion-weighted and task-related functional magnetic resonance imaging, respectively. Analyses of variance of FA and BOLD PSC were used to determine main or interaction effects of the three factors. Results A significant interaction between career duration and concussion history was observed; former college players with more than three concussions had lower FA in a broadly distributed area of white matter compared with those with zero to one concussion (t29 = 2.774; adjusted P = .037), and the opposite was observed for former professional players (t29 = 3.883; adjusted P = .001). A separate interaction between concussion history and position was observed: Nonspeed players with more than three concussions had lower FA in frontal white matter compared with those with zero to one concussion (t25 = 3.861; adjusted P = .002). Analysis of working memory-task BOLD PSC revealed a similar interaction between concussion history and position (all adjusted P < .004). Overall, former players with lower FA tended to have lower BOLD PSC across three levels of a working memory task. Conclusion Career duration and primary playing position seem to modify the effects of concussion history on white matter structure and neural recruitment. The differences in brain structure and function were observed in the absence of clinical impairment, which suggested that multimodal imaging may provide early markers of onset of traumatic neurodegenerative disease. © RSNA, 2017 Online supplemental material is available for this article.
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Beckwith JG, Zhao W, Ji S, Ajamil AG, Bolander RP, Chu JJ, McAllister TW, Crisco JJ, Duma SM, Rowson S, Broglio SP, Guskiewicz KM, Mihalik JP, Anderson S, Schnebel B, Gunnar Brolinson P, Collins MW, Greenwald RM. Estimated Brain Tissue Response Following Impacts Associated With and Without Diagnosed Concussion. Ann Biomed Eng 2018; 46:819-830. [PMID: 29470745 DOI: 10.1007/s10439-018-1999-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 02/15/2018] [Indexed: 11/28/2022]
Abstract
Kinematic measurements of head impacts are sensitive to sports concussion, but not highly specific. One potential reason is these measures reflect input conditions only and may have varying degrees of correlation to regional brain tissue deformation. In this study, previously reported head impact data recorded in the field from high school and collegiate football players were analyzed using two finite element head models (FEHM). Forty-five impacts associated with immediately diagnosed concussion were simulated along with 532 control impacts without identified concussion obtained from the same players. For each simulation, intracranial response measures (max principal strain, strain rate, von Mises stress, and pressure) were obtained for the whole brain and within four regions of interest (ROI; cerebrum, cerebellum, brain stem, corpus callosum). All response measures were sensitive to diagnosed concussion; however, large inter-athlete variability was observed and sensitivity strength depended on measure, ROI, and FEHM. Interestingly, peak linear acceleration was more sensitive to diagnosed concussion than all intracranial response measures except pressure. These findings suggest FEHM may provide unique and potentially important information on brain injury mechanisms, but estimations of concussion risk based on individual intracranial response measures evaluated in this study did not improve upon those derived from input kinematics alone.
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Lynall RC, Pietrosimone B, Kerr ZY, Mauntel TC, Mihalik JP, Guskiewicz KM. Osteoarthritis Prevalence in Retired National Football League Players With a History of Concussion and Lower Extremity Injury. J Athl Train 2018; 52:518-525. [PMID: 28653870 DOI: 10.4085/1062-6050-52.2.03] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
CONTEXT Dynamic balance deficits have been described postconcussion, even after athletes return to play. Lower extremity (LE) musculoskeletal injury rates increase for up to 1 year after concussion, but the long-term musculoskeletal implications of concussion are unclear. OBJECTIVE To (1) examine the association of concussion and LE injury histories with osteoarthritis (OA) prevalence in retired National Football League players and (2) examine the association of concussion and LE injury histories with OA prevalence in those ≤55 years of age. DESIGN Case-control study. SETTING Survey. PATIENTS OR OTHER PARTICIPANTS We administered the Health Survey of Retired National Football League Players, which collects information about demographics, OA, LE injury, and concussion history. MAIN OUTCOME MEASURE(S) Twelve discrete categories were created based on concussion and LE injury history, ranging from 0 concussions and 0 LE injuries (referent group) to 3+ concussions and 2+ LE injuries. Binomial regression analysis modeled lifetime OA prevalence. Covariates were body mass index, age at the time of the survey, and total years playing professional football. RESULTS Complete data were available for 2696 participants. Lifetime OA prevalence was smallest in the referent group (21.1%) and largest in the 3+ concussion and 2+ LE group (50.6%; 2.5 times the referent; 95% confidence interval [CI] = 2.1, 3.1). Participants in all concussion groups (1, 2, 3+) who reported a history of 0 LE injuries had a greater OA prevalence than the referent group. When participants were stratified by age, the ≤55 years of age, 3+ concussions, and 2+ LE injuries group prevalence ratio (3.6; 95% CI = 2.7, 5.2) was larger than that of the >55 years of age, 3+ concussions, and 2+ LE injuries group (1.8; 95% CI = 1.3, 2.4) compared with the respective referent groups. CONCLUSIONS Concussion with or without a history of LE injury may be an important moderator of OA. Future researchers should seek to better understand the mechanisms that influence the association among concussion, LE injury, and OA.
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Kuzminski SJ, Clark MD, Fraser MA, Haswell CC, Morey RA, Liu C, Choudhury KR, Guskiewicz KM, Petrella JR. White Matter Changes Related to Subconcussive Impact Frequency during a Single Season of High School Football. AJNR Am J Neuroradiol 2018; 39:245-251. [PMID: 29269405 DOI: 10.3174/ajnr.a5489] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 10/03/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND PURPOSE The effect of exposing the developing brain of a high school football player to subconcussive impacts during a single season is unknown. The purpose of this pilot study was to use diffusion tensor imaging to assess white matter changes during a single high school football season, and to correlate these changes with impacts measured by helmet accelerometer data and neurocognitive test scores collected during the same period. MATERIALS AND METHODS Seventeen male athletes (mean age, 16 ± 0.73 years) underwent MR imaging before and after the season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis. RESULTS The mean number of impacts over a 10-g threshold sustained was 414 ± 291. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant (P < .05, corrected) decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The effects were strongest in the fornix-stria terminalis, where decreases in fractional anisotropy correlated with worsening visual memory. CONCLUSIONS Our findings suggest that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level.
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Kerr ZY, Register-Mihalik JK, Kay MC, DeFreese JD, Marshall SW, Guskiewicz KM. Concussion Nondisclosure During Professional Career Among a Cohort of Former National Football League Athletes. Am J Sports Med 2018; 46:22-29. [PMID: 28942673 DOI: 10.1177/0363546517728264] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Despite a focus on the incidence and effects of concussion, nondisclosure of sports-related concussions among retired players from the National Football League (NFL) has yet to be examined. PURPOSE Examine the prevalence of and factors associated with nondisclosure of sports-related concussions in former NFL athletes. STUDY DESIGN Cross-sectional study; Level of evidence, 3. METHODS A sample of 829 former NFL players completed a general health survey. This historical cohort included players who had played before World War II to 2001. Respondents retrospectively recalled sports-related concussions that they sustained during their professional careers and whether at least one of these sports-related concussions was not reported to medical staff. We computed the prevalence of nondisclosure among those recalling sport-related concussions during their professional careers. Multivariable binomial regression estimated adjusted prevalence ratios (PR) with 95% confidence intervals (CIs) controlling for race/ethnicity, number of years played, primary position played, professional career concussion history, and playing era. Playing era was categorized by whether the majority of a player's career was before or after a 1976 rule change to limit contact ("spearing"). RESULTS Overall, 417 (50.3%) respondents reported they had sustained a concussion and did not inform medical staff at least once during their professional playing career. Nonwhite respondents had a higher prevalence of nondisclosure than white/non-Hispanic respondents (adjusted PR = 1.19; 95% CI, 1.02-1.38). An interaction between professional career concussion history and playing era was also found ( P = .08). Compared with those in the pre-spearing rule change group with 1 or 2 concussions, all other groups had larger prevalences of nondisclosure (increases ranging from 41% to 153% in multivariable models). Across concussion strata, nondisclosure prevalence was generally higher in the post-spearing rule change group than the pre-spearing rule change group, with the largest differences found among those with 1 or 2 concussions or those with 3 or 4 concussions. CONCLUSION A large proportion of former NFL players in this historical cohort reported at least one instance of not disclosing sports-related concussions to medical staff. Future research on concussion nondisclosure needs to identify mechanisms to improve football players' intentions to disclose concussion-related symptoms to health care providers and to equip health care providers with more effective strategies for timely identification of concussion.
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Santo A, Lynall RC, Guskiewicz KM, Mihalik JP. Clinical Utility of the Sport Concussion Assessment Tool 3 (SCAT3) Tandem-Gait Test in High School Athletes. J Athl Train 2017; 52:1096-1100. [PMID: 29172647 DOI: 10.4085/1062-6050-52.11.26] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Dynamic balance during functional movement may provide important clinical information after concussion. The Sport Concussion Assessment Tool, version 3 (SCAT3), includes a timed tandem-gait test (heel-to-toe walking) administered with a pass-fail scoring system. Minimal evidence supports inclusion of the tandem-gait test in the SCAT3, especially in high school athletes. OBJECTIVE To determine (1) the percentage of healthy high school athletes who passed (best trial ≤14 seconds) the tandem-gait test at baseline, (2) the association between sex and test performance (pass versus fail), and (3) the relationships among sex, age, height, and tandem-gait test score. DESIGN Cross-sectional study. SETTING High school sports medicine center. PATIENTS OR OTHER PARTICIPANTS Two hundred athletes from 4 high schools (age = 15.8 ± 1.2 years, height = 170.3 ± 10.3 cm, weight = 64.8 ± 14.5 kg). MAIN OUTCOME MEASURE(S) Healthy participants completed 4 trials of the SCAT3 tandem-gait test and a demographic questionnaire. Outcome measures were passing rate at baseline on the tandem-gait test and tandem-gait test score (time). RESULTS Overall, 24.5% (49/200) of participants passed the test. Sex and performance were associated (χ2 = 15.15, P < .001), with a passing rate of 38.6% (32/83) for males and 14.5% (17/117) for females. The regression model including predictor variables of sex and height, with the outcome variable of tandem-gait test score and time, was significant ( R2 = 0.20, P < .01). CONCLUSIONS Our findings suggest that the tandem-gait test had a high false-positive rate in high school athletes. Given that more than 75% of healthy participants failed the tandem-gait test, the 14-second cutoff appears to have limited clinical utility in the adolescent population. Functional movement deficits after concussion need to be accounted for, but the 14-second cutoff for the SCAT3 tandem-gait test does not appear to be an ideal way to assess these deficits in high school athletes.
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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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Teel EF, Marshall SW, Shankar V, McCrea M, Guskiewicz KM. Predicting Recovery Patterns After Sport-Related Concussion. J Athl Train 2017; 52:288-298. [PMID: 28387552 DOI: 10.4085/1062-6050-52.1.12] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Clinicians sometimes treat concussed individuals who have amnesia, loss of consciousness (LOC), a concussion history, or certain symptom types more conservatively, but it is unclear whether recovery patterns differ in individuals with these characteristics. OBJECTIVE To determine whether (1) amnesia, LOC, and concussion history influence the acute recovery of symptoms, cognition, and balance; and (2) cognition and balance are influenced by acute symptom type. DESIGN Cohort study. SETTING Seven sports at 26 colleges and 210 high schools. PATIENTS OR OTHER PARTICIPANTS A total of 8905 collegiate (n = 1392) and high school (n = 7513) athletes. MAIN OUTCOME MEASURE(S) The Graded Symptom Checklist, Standardized Assessment of Concussion, and Balance Error Scoring System were administered to all athletes during the preseason. To allow us to track recovery patterns, athletes diagnosed with a concussion (n = 375) repeated these assessments immediately after the injury, 3 hours postinjury, 1 day postinjury, and at 2, 3, 5, 7, and 90 days after injury. RESULTS Athletes who experienced amnesia had markedly greater deficits in and a slower recovery trajectory on measures of symptoms, cognition, and balance. Athletes with 2 or more prior concussions demonstrated poorer balance than those with no previous history. Otherwise, LOC and concussion history largely did not affect symptoms, cognition, or balance. Greater deficits in balance scores were observed in athletes with all symptom types. Regardless of these characteristics, most athletes recovered within 7 to 10 days. CONCLUSIONS Athletes who experienced amnesia had more symptoms and greater deficits in cognition and balance. Symptoms and cognitive or balance deficits were not consistently associated with LOC or concussion history. Acute symptoms had a strong influence on balance scores and, to a lesser extent, on cognition. However, we found no evidence to support more cautious return-to-play decisions for athletes with these characteristics, as group recovery occurred within normal timelines. Our study supports current clinical practice: recommending that athletes be withheld from activity until they are asymptomatic, followed by a graduated return-to-play progression.
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Broglio SP, Guskiewicz KM, Norwig J. If You're Not Measuring, You're Guessing: The Advent of Objective Concussion Assessments. J Athl Train 2017; 52:160-166. [PMID: 28387562 DOI: 10.4085/1062-6050-51.9.05] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sport-related concussion remains one of the most complex injuries presented to sports medicine professionals. Although the injury has been recognized since ancient times, the concussion-assessment process has seen significant advances over the last 30 years. This review outlines the addition of objective measures to the clinical evaluation of the concussed athlete, beginning in the 1980s and continuing through the modern age. International and domestic organizations now describe standardized symptom reports, neurostatus and neurocognitive-function evaluations, and postural-control measures as standards of medical care, a significant shift from a short time ago. Despite this progression, much about the injury remains unknown, including new clinical and research-based assessment techniques and how the injury may influence the athlete's cognitive health over the long term.
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Wasserman EB, Mihalik JP, Campbell KR, Combs P, Fraser MA, Grand E, Nocera M, Register-Mihalik JK, Guskiewicz KM, Marshall SW. Innovative behaviourbehavior modification strategies to reduce concussion risk in high school american football athletes. Br J Sports Med 2017. [DOI: 10.1136/bjsports-2016-097270.174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Lynall RC, Blackburn JT, Guskiewicz KM, Marshall SW, Plummer P, Mihalik JP. Deficits in dynamic balance during tandem gait after concussion may be exacerbated by dual-tasks. Br J Sports Med 2017. [DOI: 10.1136/bjsports-2016-097270.128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Echemendia RJ, Broglio SP, Davis GA, Guskiewicz KM, Hayden KA, Leddy JJ, Meehan WP, Putukian M, Sullivan SJ, Schneider KJ, McCrory P. What tests and measures should be added to the SCAT3 and related tests to improve their reliability, sensitivity and/or specificity in sideline concussion diagnosis? A systematic review. Br J Sports Med 2017; 51:895-901. [DOI: 10.1136/bjsports-2016-097466] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 11/03/2022]
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Fraser MA, Grooms DR, Guskiewicz KM, Kerr ZY. Ball-Contact Injuries in 11 National Collegiate Athletic Association Sports: The Injury Surveillance Program, 2009-2010 Through 2014-2015. J Athl Train 2017; 52:698-707. [PMID: 28535098 DOI: 10.4085/1062-6050-52.3.10] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Surveillance data regarding injuries caused by ball contact in collegiate athletes have not been well examined and are mostly limited to discussions of concussions and catastrophic injuries. OBJECTIVE To describe the epidemiology of ball-contact injuries in 11 National Collegiate Athletic Association (NCAA) sports during the 2009-2010 through 2014-2015 academic years. DESIGN Descriptive epidemiology study. SETTING Convenience sample of NCAA programs in 11 sports (men's football, women's field hockey, women's volleyball, men's baseball, women's softball, men's and women's basketball, men's and women's lacrosse, and men's and women's soccer) during the 2009-2010 through 2014-2015 academic years. PATIENTS OR OTHER PARTICIPANTS Collegiate student-athletes participating in 11 sports. MAIN OUTCOME MEASURE(S) Ball-contact-injury rates, proportions, rate ratios, and proportion ratios with 95% confidence intervals were based on data from the NCAA Injury Surveillance Program during the 2009-2010 through 2014-2015 academic years. RESULTS During the 2009-2010 through 2014-2015 academic years, 1123 ball-contact injuries were reported, for an overall rate of 3.54/10 000 AEs. The sports with the highest rates were women's softball (8.82/10 000 AEs), women's field hockey (7.71/10 000 AEs), and men's baseball (7.20/10 000 AEs). Most ball-contact injuries were to the hand/wrist (32.7%) and head/face (27.0%) and were diagnosed as contusions (30.5%), sprains (23.1%), and concussions (16.1%). Among sex-comparable sports (ie, baseball/softball, basketball, and soccer), women had a larger proportion of ball-contact injuries diagnosed as concussions than men (injury proportion ratio = 2.33; 95% confidence interval = 1.63, 3.33). More than half (51.0%) of ball-contact injuries were non-time loss (ie, participation-restriction time <24 hours), and 6.6% were severe (ie, participation-restriction time ≥21 days). The most common severe ball-contact injuries were concussions (n = 18) and finger fractures (n = 10). CONCLUSION Ball-contact-injury rates were the highest in women's softball, women's field hockey, and men's baseball. Although more than half were non-time-loss injuries, severe injuries such as concussions and fractures were reported.
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Mihalik JP, Sumrall AZ, Yeargin SW, Guskiewicz KM, King KB, Trulock SC, Shields EW. Environmental and Physiological Factors Affect Football Head Impact Biomechanics. Med Sci Sports Exerc 2017; 49:2093-2101. [PMID: 28509764 DOI: 10.1249/mss.0000000000001325] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Recent anecdotal trends suggest a disproportionate number of head injuries in collegiate football players occur during preseason football camp. In warmer climates, this season also represents the highest risk for heat-related illness among collegiate football players. Because concussion and heat illnesses share many common symptoms, we need 1) to understand if environmental conditions, body temperature, and hydration status affect head impact biomechanics; and 2) to determine if an in-helmet thermistor could provide a valid measure of gastrointestinal temperature. METHODS A prospective cohort of 18 Division I college football players (age, 21.1 ± 1.4 yr; height, 187.7 ± 6.6 cm; mass, 114.5 ± 23.4 kg). Data were collected during one control and three experimental sessions. During each session, the Head Impact Telemetry System recorded head impact biomechanics (linear acceleration, rotational acceleration, and severity profile) and in-helmet temperature. A wet bulb globe device recorded environmental conditions, and CorTemp™ Ingestible Core Body Temperature Sensors recorded gastrointestinal temperature. RESULTS Our findings suggest that linear acceleration (P = 0.57), rotational acceleration (P = 0.16), and Head Impact Technology severity profile (P = 0.33) are not influenced by environmental or physiological conditions. CONCLUSIONS We did not find any single or combination of predictors for impact severity. Rotational acceleration was approaching significance between our early experimental sessions when compared with our control session. More research should be conducted to better understand if rotational accelerations are a component of impact magnitudes that are affected due to changes in environmental conditions, body temperature, and hydration status.
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Makdissi M, Schneider KJ, Feddermann-Demont N, Guskiewicz KM, Hinds S, Leddy JJ, McCrea M, Turner M, Johnston KM. Approach to investigation and treatment of persistent symptoms following sport-related concussion: a systematic review. Br J Sports Med 2017; 51:958-968. [DOI: 10.1136/bjsports-2016-097470] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2017] [Indexed: 11/03/2022]
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Lynall RC, Campbell KR, Blackburn JT, Guskiewicz KM, Marshall SW, Plummer P, Mihalik JP. Dynamic Balance Deficits Following Concussion. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518416.44622.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vander Vegt CB, Register-Mihalik JK, Rodrigo CJ, Kay MC, Guskiewicz KM, Mihalik JP. Association Between Concussion History, Demographic Characteristics, And Sensory Organization In Collegiate Athletes. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518012.08713.d0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Register-Mihalik JK, Bloom OJ, Fonseca J, Phillips K, Kay MC, Vander Vegt CB, Gallini JW, Guskiewicz KM, De Maio VJ. Relationship Between Initial Post-concussion Presentation And Health-related Quality Of Life At One Month Post-injury In Pediatric Concussion Patients. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518015.54454.1e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Manley G, Gardner AJ, Schneider KJ, Guskiewicz KM, Bailes J, Cantu RC, Castellani RJ, Turner M, Jordan BD, Randolph C, Dvořák J, Hayden KA, Tator CH, McCrory P, Iverson GL. A systematic review of potential long-term effects of sport-related concussion. Br J Sports Med 2017; 51:969-977. [PMID: 28455362 PMCID: PMC5466926 DOI: 10.1136/bjsports-2017-097791] [Citation(s) in RCA: 365] [Impact Index Per Article: 52.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2017] [Indexed: 12/14/2022]
Abstract
Objective Systematic review of possible long-term effects of sports-related concussion in retired athletes. Data sources Ten electronic databases. Study selection Original research; incidence, risk factors or causation related to long-term mental health or neurological problems; individuals who have suffered a concussion; retired athletes as the subjects and possible long-term sequelae defined as >10 years after the injury. Data extraction Study population, exposure/outcome measures, clinical data, neurological examination findings, cognitive assessment, neuroimaging findings and neuropathology results. Risk of bias and level of evidence were evaluated by two authors. Results Following review of 3819 studies, 47 met inclusion criteria. Some former athletes have depression and cognitive deficits later in life, and there is an association between these deficits and multiple prior concussions. Former athletes are not at increased risk for death by suicide (two studies). Former high school American football players do not appear to be at increased risk for later life neurodegenerative diseases (two studies). Some retired professional American football players may be at increased risk for diminishment in cognitive functioning or mild cognitive impairment (several studies), and neurodegenerative diseases (one study). Neuroimaging studies show modest evidence of macrostructural, microstructural, functional and neurochemical changes in some athletes. Conclusion Multiple concussions appear to be a risk factor for cognitive impairment and mental health problems in some individuals. More research is needed to better understand the prevalence of chronic traumatic encephalopathy and other neurological conditions and diseases, and the extent to which they are related to concussions and/or repetitive neurotrauma sustained in sports.
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McCrory P, Meeuwisse W, Dvorak J, Aubry M, Bailes J, Broglio S, Cantu RC, Cassidy D, Echemendia RJ, Castellani RJ, Davis GA, Ellenbogen R, Emery C, Engebretsen L, Feddermann-Demont N, Giza CC, Guskiewicz KM, Herring S, Iverson GL, Johnston KM, Kissick J, Kutcher J, Leddy JJ, Maddocks D, Makdissi M, Manley GT, McCrea M, Meehan WP, Nagahiro S, Patricios J, Putukian M, Schneider KJ, Sills A, Tator CH, Turner M, Vos PE. Consensus statement on concussion in sport—the 5thinternational conference on concussion in sport held in Berlin, October 2016. Br J Sports Med 2017; 51:838-847. [DOI: 10.1136/bjsports-2017-097699] [Citation(s) in RCA: 917] [Impact Index Per Article: 131.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 11/03/2022]
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Schneider KJ, Leddy JJ, Guskiewicz KM, Seifert T, McCrea M, Silverberg ND, Feddermann-Demont N, Iverson GL, Hayden A, Makdissi M. Rest and treatment/rehabilitation following sport-related concussion: a systematic review. Br J Sports Med 2017; 51:930-934. [PMID: 28341726 DOI: 10.1136/bjsports-2016-097475] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2017] [Indexed: 12/19/2022]
Abstract
AIM OR OBJECTIVE The objective of this systematic review was to evaluate the evidence regarding rest and active treatment/rehabilitation following sport-related concussion (SRC). DESIGN Systematic review. DATA SOURCES MEDLINE (OVID), CINAHL (EbscoHost), PsycInfo (OVID), Cochrane Central Register of Controlled Trials (OVID), SPORTDiscus (EbscoHost), EMBASE (OVID) and Proquest DissertationsandTheses Global (Proquest) were searched systematically. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Studies were included if they met the following criteria: (1) original research; (2) reported SRC as the diagnosis; and (3) evaluated the effect of rest or active treatment/rehabilitation. Review articles were excluded. RESULTS Twenty-eight studies met the inclusion criteria (9 regarding the effects of rest and 19 evaluating active treatment). The methodological quality of the literature was limited; only five randomised controlled trials (RCTs) met the eligibility criteria. Those RCTs included rest, cervical and vestibular rehabilitation, subsymptom threshold aerobic exercise and multifaceted collaborative care. SUMMARY/CONCLUSIONS A brief period (24-48 hours) of cognitive and physical rest is appropriate for most patients. Following this, patients should be encouraged to gradually increase activity. The exact amount and duration of rest are not yet well defined and require further investigation. The data support interventions including cervical and vestibular rehabilitation and multifaceted collaborative care. Closely monitored subsymptom threshold, submaximal exercise may be of benefit. SYSTEMATIC REVIEW REGISTRATION PROSPERO 2016:CRD42016039570.
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Clark MD, Asken BM, Marshall SW, Guskiewicz KM. Descriptive Characteristics of Concussions in National Football League Games, 2010-2011 to 2013-2014. Am J Sports Med 2017; 45:929-936. [PMID: 28056179 DOI: 10.1177/0363546516677793] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Despite a high reported incidence rate of concussion, little is known about the on-field characteristics of injurious head impacts in National Football League (NFL) games. PURPOSE To characterize on-field features (location, player position, and time during game) and biomechanical features (anticipation status, closing distance, impact location and type) associated with concussions in NFL games over a 4-season period (2010-2011 to 2013-2014). STUDY DESIGN Descriptive epidemiology study. METHODS We analyzed video of a subset of reported, in-game concussions for the 2010-2011 to 2013-2014 seasons. These videos represented a sample of injuries that were diagnosed and reported on the same day and that could be clearly associated with an in-game collision as captured on video. We determined anticipation status, closing distance, impact location on the injured player's helmet, and impact type (helmet-to-helmet, helmet-to-body, or helmet-to-ground). Associations between these variables were analyzed by use of descriptive statistics and tests of association. RESULTS A total of 871 diagnosed concussions were reported as occurring during NFL preseason, regular season, and postseason games for the 2010-2011, 2011-2012, 2012-2013, and 2013-2014 seasons. A total of 1324 games were played during this period, giving a concussion incidence rate of 0.658 per game (95% CI, 0.61-0.70). From the video-reviewed subset (n = 429; 49.3%), the majority of injurious impacts occurred with good anticipation (57.3%) and <10 yards of closing distance (59.0%). An association was found between anticipation status and play type ([Formula: see text] = 27.398, P < .001), largely because injuries occurring on pass plays were more likely to be poorly anticipated than injuries during run plays (43.0% vs 21.4%; [Formula: see text] = 14.78, P < .001). Kick returns had the greatest proportion of well-anticipated impacts (78%) and the greatest proportion of impacts with ≥10 yards of closing distance (80%). The type of impact was approximately equally divided between helmet-to-helmet, helmet-to-body, and helmet-to-ground types. The impact location was broadly distributed over the helmet of the injured player. CONCLUSION In-game concussions in the NFL occurred through a diverse variety of mechanisms, surprisingly tended to be well-anticipated, and, also surprisingly, occurred with <10 yards of closing distance. The impacts causing concussion were broadly distributed over the helmet. More concussions occurred during the second half of game play, but we do not have evidence to explain this finding.
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Kucera KL, Yau RK, Register-Mihalik J, Marshall SW, Thomas LC, Wolf S, Cantu RC, Mueller FO, Guskiewicz KM. Traumatic Brain and Spinal Cord Fatalities Among High School and College Football Players — United States, 2005–2014. MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT 2017; 65:1465-1469. [DOI: 10.15585/mmwr.mm6552a2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Schmidt JD, Guskiewicz KM, Mihalik JP, Blackburn JT, Siegmund GP, Marshall SW. Head Impact Magnitude in American High School Football. Pediatrics 2016; 138:peds.2015-4231. [PMID: 27432843 DOI: 10.1542/peds.2015-4231] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects (α = 0.05). RESULTS The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P = .03); contact with another player (linear, rotational, HITsp: P < .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P < .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P < .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered.
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Pietrosimone B, Golightly YM, Mihalik JP, Guskiewicz KM. Concussion Frequency Associates with Musculoskeletal Injury in Retired NFL Players. Med Sci Sports Exerc 2016; 47:2366-72. [PMID: 25871466 DOI: 10.1249/mss.0000000000000684] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Concussion is commonly associated with immediate and persistent alterations in motor function affecting postural control and gait. Patients with lower extremity joint injury have demonstrated functional alterations in the cerebral cortex, suggesting that musculoskeletal injury may be linked to alterations in brain function. Therefore, we examined the associations between concussion frequency and lower extremity musculoskeletal injury sustained during professional careers of National Football League (NFL) players in a cross-sectional study. METHODS An inclusive health history survey was mailed to 3647 NFL players who retired during 1930-2001. Respondents reported total concussion frequency (zero, one, two, or three or more) and presence (yes/no) of specific knee and ankle musculoskeletal injury during their NFL career. Separate logistic regression models were used to estimate associations between concussion frequency and each musculoskeletal injury type, adjusting for number of years played in the NFL, body mass index while playing in the NFL, and playing position. RESULTS Data from 2429 players (66.6% response rate) were available for analysis. Nearly 61% reported experiencing a concussion while competing in the NFL. Meniscal tear was the most commonly reported musculoskeletal injury (32%). Compared with NFL players who did not sustain a concussion, retired NFL players with one, two, or three or more concussions had between 18% and 63%, 15% and 126%, and 73% and 165% higher odds of reporting various musculoskeletal injuries, respectively. CONCLUSIONS A history of concussions was associated with a history of musculoskeletal injuries during NFL careers. These data suggest that a higher number of concussions is linked with higher odds of reporting a musculoskeletal injury.
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Asken BM, Mihalik JP, Schmidt JD, Littleton AC, Guskiewicz KM, Hopfinger JB. Visual Performance Measures and Functional Implications in Healthy Participants: A Sports Concussion Perspective. ACTA ACUST UNITED AC 2016. [DOI: 10.3928/19425864-20160204-03] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Schmidt JD, Pierce AF, Guskiewicz KM, Register-Mihalik JK, Pamukoff DN, Mihalik JP. Safe-Play Knowledge, Aggression, and Head-Impact Biomechanics in Adolescent Ice Hockey Players. J Athl Train 2016; 51:366-72. [PMID: 27111585 DOI: 10.4085/1062-6050-51.5.04] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Addressing safe-play knowledge and player aggression could potentially improve ice hockey sport safety. OBJECTIVES To compare (1) safe-play knowledge and aggression between male and female adolescent ice hockey players and (2) head-impact frequency and severity between players with high and low levels of safe-play knowledge and aggression during practices and games. DESIGN Cohort study. SETTING On field. PATIENTS OR OTHER PARTICIPANTS Forty-one male (n = 29) and female (n = 12) adolescent ice hockey players. INTERVENTION(S) Players completed the Safe Play Questionnaire (0 = less knowledge, 7 = most knowledge) and Competitive Aggressiveness and Anger Scale (12 = less aggressive, 60 = most aggressive) at midseason. Aggressive penalty minutes were recorded throughout the season. The Head Impact Telemetry System was used to capture head-impact frequency and severity (linear acceleration [g], rotational acceleration [rad/s(2)], Head Impact Technology severity profile) at practices and games. MAIN OUTCOME MEASURE(S) One-way analyses of variance were used to compare safe play knowledge and aggression between sexes. Players were categorized as having high or low safe-play knowledge and aggression using a median split. A 2 × 2 mixed-model analysis of variance was used to compare head-impact frequency, and random-intercept general linear models were used to compare head-impact severity between groups (high, low) and event types (practice, game). RESULTS Boys (5.8 of 7 total; 95% confidence interval [CI] = 5.3, 6.3) had a trend toward better safe-play knowledge compared with girls (4.9 of 7 total; 95% CI = 3.9, 5.9; F1,36 = 3.40, P = .073). Less aggressive male players sustained significantly lower head rotational accelerations during practices (1512.8 rad/s (2) , 95% CI = 1397.3, 1637.6 rad/s(2)) versus games (1754.8 rad/s (2) , 95% CI = 1623.9, 1896.2 rad/s(2)) and versus high-aggression players during practices (1773.5 rad/s (2) , 95% CI = 1607.9, 1956.3 rad/s (2) ; F1,26 = 6.04, P = .021). CONCLUSIONS Coaches and sports medicine professionals should ensure that athletes of all levels, ages, and sexes have full knowledge of safe play and should consider aggression interventions for reducing head-impact severity among aggressive players during practice.
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