scholarly journals Subconcussive brain vital signs changes predict head-impact exposure in ice hockey players

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Shaun D Fickling ◽  
Aynsley M Smith ◽  
Michael J Stuart ◽  
David W Dodick ◽  
Kyle Farrell ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Vital Sign ◽  
Brain Function ◽  
Point Of Care ◽  
Vital Signs ◽  
Head Impact ◽  
Ice Hockey ◽  
Head Impacts ◽  
Hockey Players ◽  
The Brain

Abstract The brain vital signs framework is a portable, objective, neurophysiological evaluation of brain function at point-of-care. We investigated brain vital signs at pre- and post-season for age 14 or under (Bantam) and age 16–20 (Junior-A) male ice hockey players to (i) further investigate previously published brain vital sign results showing subconcussive cognitive deficits and (ii) validate these findings through comparison with head-impact data obtained from instrumented accelerometers. With a longitudinal study design, 23 male ice hockey players in Bantam (n = 13; age 13.63 ± 0.62) and Tier II Junior-A (n = 10; age 18.62 ± 0.86) divisions were assessed at pre- and post-season. None were diagnosed with a concussion during the season. Cognitive evoked potential measures of Auditory sensation (N100), Basic attention (P300) and Cognitive processing (N400) were analysed as changes in peak amplitudes and latencies (six standard scores total). A regression analysis examined the relationship between brain vital signs and the number of head impacts received during the study season. Significant pre/post differences in brain vital signs were detected for both groups. Bantam and Junior-A players also differed in number of head impacts (Bantam: 32.92 ± 17.68; Junior-A: 195.00 ± 61.08; P < 0.001). Importantly, the regression model demonstrated a significant linear relationship between changes in brain vital signs and total head impacts received (R = 0.799, P = 0.007), with clear differences between the Bantam and Junior-A groups. In the absence of a clinically diagnosed concussion, the brain vital sign changes appear to have demonstrated the compounding effects of repetitive subconcussive impacts. The findings underscored the importance of an objective physiological measure of brain function along the spectrum of concussive impacts.

scholarly journals Relationships between Head Impacts, Competitive Aggression, and Risk-taking Behavior in Collegiate Ice Hockey Players

2019 ◽  
Vol 34 (5) ◽  
pp. 780-780
Author(s):  
M S DiFabio ◽  
T A Buckley
Keyword(s):  
Risk Taking ◽  
Sensation Seeking ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Impact Loads ◽  
Head Impacts ◽  
Hockey Players ◽  
Risk Taking Behavior ◽  
Sensation Seeking Scale

Abstract Purpose To examine relationships between head impact kinematics sustained over a season and competitive aggression and self-reported risk-taking behavior in collegiate club ice-hockey athletes. Methods Twenty male ice-hockey players (19.9±1.2 y.o, 1.8±0.06 m, 78.5±5.7 kg) completed the Competitive Anger and Aggression Scale (CAAS, Range:0-84) and the Brief Sensation Seeking Scale (BSSS, Range:8-40) during the preseason as measures of competitive aggression and risk-taking behavior with higher/lower reflecting higher/lower aggression and risk taking. Penalty minutes (PM) and games played (GP) were taken from official game records. Head impact kinematics (number of impacts, linear mean, peak, cumulative acceleration) were recorded by tri-axial accelerometers worn during games/practices. Spearman correlation was performed to examine relationships between variables. Results The mean number of impacts was 76.6±54.9 (range: 6–171); mean and cumulative acceleration were 36.3±4.2g (range:27.8–42.2g) and 2829.4±2024.9g (range:198.4–6527.2g), respectively. Neither CAAS (mean: 48.7±10.9, range: 24–64) nor BSSS scores (mean: 25.3±4.4, range:15–32) were significantly related to impact kinematics. GP was significantly correlated with number of impacts (r=.63, p=.003) and cumulative linear acceleration (r=.61, p=.004). PM was significantly correlated with number of impacts (r=.52, p=.20) and cumulative linear acceleration (r=.55, p=.13). Conclusion There were no relationships between the head impact kinematics and self-reported aggressiveness or risk taking behavior, but more PM was strongly related to higher head impact loads. Considering PM may be useful in aiding to identify athletes who may sustain higher head impact loads, however, self-reports of behavior may not be.

scholarly journals THE EFFECT OF A BODY CHECKING RULE CHANGE ON HEAD IMPACT BIOMECHANICS IN BANTAM ICE HOCKEY ATHLETES

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0021
Author(s):  
Patricia R. Combs ◽  
Cassie B. Ford ◽  
Elizabeth F. Teel ◽  
Erin B. Wasserman ◽  
Michael J. Cools ◽  
...  
Keyword(s):  
Injury Risk ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Rotational Acceleration ◽  
Body Checking ◽  
Head Impacts ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics ◽  
Hockey Players

Background: Body checking is the most common injury mechanism in ice hockey. Rule changes have sought to mitigate body checking exposure among youth players. In 2011, USA Hockey changed the legal body checking age from Pee Wee (11/12-year-olds) to Bantam (13/14-year-olds). Interestingly, Bantam players with checking experience during Pee Wee had a lower concussion risk relative to Bantam players without checking experience in a sample of Canadian youth hockey players. Understanding the head impact biomechanics underlying these findings could further elucidate the consequences of this rule change. Purpose: To determine the association between Pee Wee checking exposure and head impact biomechanics in a cohort of Bantam players. Methods: We prospectively collected data on Bantam ice hockey players during the 2006/07-2009/10 seasons and the 2012-2013 season. The 2006/07-2009/10 cohort (n= 61, age=13.9±0.5 years, height=168.2±8.7 cm, mass=59.9±10.4 kg) was allowed to body check (BC) as a Pee Wee player. The 2012-2013 cohort (n=15, age=13.3±0.4 years, height=167.5±7.4 cm, mass=57.5±8.6 kg) was not permitted to body check (NBC) as a Pee Wee player. Over the course of each season, head impacts were measured using in-helmet accelerometers. Only head impacts with linear acceleration ≥10 g were included in our analysis. Main outcome measures were mean linear acceleration (g) and rotational acceleration (rad/s2). Levene’s tests assessed equality of variance between groups. We employed mixed effects models to assess group differences in mean linear and rotational acceleration between BC and NBC groups. Results: The BC and NBC groups did not differ in height (t74=0.28, p=0.78) or mass (t74=0.84, p=0.40). When assessing group differences in head impact biomechanics, the NBC experienced significantly greater linear acceleration (F1,74=4.36, p=0.04) and greater rotational acceleration (F1,74=21.2, p<0.001) relative to the BC group. On average, the NBC group experienced 23.1 ± 0.87 g linear acceleration and 1993.5 ± 68.4 rad/s2 rotational acceleration compared to the BC group, which experienced 21.2 ± 0.30 g linear acceleration and 1615.9 ± 45.2 rad/s2 rotational acceleration. Conclusions: Bantam ice hockey players without body checking experience during their Pee Wee years experienced greater average linear and rotational acceleration relative to players with Pee Wee body checking experience. While removing body checking from Pee Wee ice hockey may reduce short-term injury risk, these athletes may demonstrate more high-risk head impact biomechanics when legally allowed to body check. Future research should continue to examine the influence of policy changes on head impact biomechanics and injury risk in youth ice hockey. [Figure: see text]

scholarly journals Effect of Head Impact Exposures on Changes in Cognitive Testing

2018 ◽  
Vol 6 (3) ◽  
pp. 232596711876103 ◽  
Author(s):  
Eleni Diakogeorgiou ◽  
Theresa L. Miyashita
Keyword(s):  
Reaction Time ◽  
National Collegiate Athletic Association ◽  
Assessment Tool ◽  
Vital Signs ◽  
Head Impact ◽  
Cognitive Testing ◽  
Repeated Impact ◽  
Level Of Evidence ◽  
Head Impacts ◽  
Significant Difference

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 >20 g 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.

scholarly journals Spectrum of acute clinical characteristics of diagnosed concussions in college athletes wearing instrumented helmets

2012 ◽  
Vol 117 (6) ◽  
pp. 1092-1099 ◽  
Author(s):  
Ann-Christine Duhaime ◽  
Jonathan G. Beckwith ◽  
Arthur C. Maerlender ◽  
Thomas W. McAllister ◽  
Joseph J. Crisco ◽  
...  
Keyword(s):  
Collegiate Athletes ◽  
Head Impact ◽  
Ice Hockey ◽  
Future Research ◽  
Impact Event ◽  
Head Impacts ◽  
Presenting Symptoms ◽  
Wide Range ◽  
Impact Events ◽  
Specific Impact

Object Concussive head injuries have received much attention in the medical and public arenas, as concerns have been raised about the potential short- and long-term consequences of injuries sustained in sports and other activities. While many student athletes have required evaluation after concussion, the exact definition of concussion has varied among disciplines and over time. The authors used data gathered as part of a multiinstitutional longitudinal study of the biomechanics of head impacts in helmeted collegiate athletes to characterize what signs, symptoms, and clinical histories were used to designate players as having sustained concussions. Methods Players on 3 college football teams and 4 ice hockey teams (male and female) wore helmets instrumented with Head Impact Telemetry (HIT) technology during practices and games over 2–4 seasons of play. Preseason clinical screening batteries assessed baseline cognition and reported symptoms. If a concussion was diagnosed by the team medical staff, basic descriptive information was collected at presentation, and concussed players were reevaluated serially. The specific symptoms or findings associated with the diagnosis of acute concussion, relation to specific impact events, timing of symptom onset and diagnosis, and recorded biomechanical parameters were analyzed. Results Data were collected from 450 athletes with 486,594 recorded head impacts. Forty-eight separate concussions were diagnosed in 44 individual players. Mental clouding, headache, and dizziness were the most common presenting symptoms. Thirty-one diagnosed cases were associated with an identified impact event; in 17 cases no specific impact event was identified. Onset of symptoms was immediate in 24 players, delayed in 11, and unspecified in 13. In 8 cases the diagnosis was made immediately after a head impact, but in most cases the diagnosis was delayed (median 17 hours). One diagnosed concussion involved a 30-second loss of consciousness; all other players retained alertness. Most diagnoses were based on self-reported symptoms. The mean peak angular and rotational acceleration values for those cases associated with a specific identified impact were 86.1 ± 42.6g (range 16.5–177.9g) and 3620 ± 2166 rad/sec2 (range 183–7589 rad/sec2), respectively. Conclusions Approximately two-thirds of diagnosed concussions were associated with a specific contact event. Half of all players diagnosed with concussions had delayed or unclear timing of onset of symptoms. Most had no externally observed findings. Diagnosis was usually based on a range of self-reported symptoms after a variable delay. Accelerations clustered in the higher percentiles for all impact events, but encompassed a wide range. These data highlight the heterogeneity of criteria for concussion diagnosis, and in this sports context, its heavy reliance on self-reported symptoms. More specific and standardized definitions of clinical and objective correlates of a “concussion spectrum” may be needed in future research efforts, as well as in the clinical diagnostic arena.

scholarly journals Head Impact Kinematics do not Predict In-Season Concussion or Lower Extremity Injury in Ice Hockey

Neurology ◽  
2019 ◽  
Vol 93 (14 Supplement 1) ◽  
pp. S30.2-S31
Author(s):  
Melissa DiFabio ◽  
Katherine Breedlove ◽  
Thomas Buckley
Keyword(s):  
Lower Extremity ◽  
Linear Acceleration ◽  
Mean Value ◽  
Small Sample ◽  
Head Impact ◽  
Ice Hockey ◽  
Lower Extremity Injury ◽  
Extremity Injury ◽  
Head Impacts ◽  
Increased Risk

ObjectiveTo examine if head impact kinematics (HIK) predict in-season concussion or acute lower extremity injury (LEI) in collegiate ice hockey.BackgroundSustaining head impacts in sport regularly may be damaging to long-term neurological health. Individuals who sustain higher head impact loads may be at increased risk for concussion, and furthermore, individuals who sustain a concussion are more likely to sustain a subsequent LEI than those without a history of concussion.Design/MethodsTwenty-nine collegiate club male ice hockey players (age: 20.2 ± 1.4) over the 2015-2018 seasons completed a survey at the conclusion of their season of LEI and concussion in-season. HIK (number of impacts, and mean, peak, and cumulative linear acceleration) were recorded via tri-axial accelerometers (Triax, Nowalk, CT) that each player wore for games/practices with a 10g impact threshold. Two binary logistic regressions were performed to determine if either sustaining a concussion or LEI was predicted by HIK.ResultsThere was no relationship between LEI or concussion with number of impacts (β:-0.018, p = 0.711, 95% CI:-0.12-0.84; β:-0.039, p = 0.55, 95% CI: -0.21-0.08, respectively), or mean (β:0.041, p = 0.79, 95% CI: -0.26-0.38; β:-0.040, p = 0.81, 95% CI: -0.37-0.32), peak (β:-0.065, p = 0.14, 95% CI: -0.16-0.01; β:0.0007, p = 0.99, 95% CI: -0.09-0.09), or cumulative acceleration (β:0.001, p = 0.42, 95% CI: -0.001-0.004; β:0.001, p = 0.55, 95% CI:-0.002-0.005). 7/29 players sustained a LEI and 6/29 sustained a concussion. Mean value for number of impacts was 59.7 ± 49.1 (range:3-171); mean acceleration: 33.9 ± 5.3g (range:22.0-42.22), peak: 71.8 ± 19.0g (range: 30.8-108.4); cumulative: 2,108.5 ± 1,793.8g (range 71.8-6517.2).ConclusionsThe main finding of this study is that greater HIK do not predict whether individuals sustained either an acute LEI or concussion during the season, albeit from a small sample. As HIK load is related to concussion incidence, it is possible HIK load may also be related to LEI, however, these results suggest HIK alone is not related to either in an ice hockey cohort.

scholarly journals Is the Brain an Early or Late Component of Essential Hypertension?

2020 ◽  
Vol 33 (6) ◽  
pp. 482-490 ◽  
Author(s):  
John Richard Jennings ◽  
Matthew F Muldoon ◽  
Alan F Sved
Keyword(s):  
Essential Hypertension ◽  
Cognitive Processing ◽  
Brain Function ◽  
Specific Pattern ◽  
Cerebrovascular Function ◽  
Causative Factors ◽  
Inflammatory Activation ◽  
System Activation ◽  
The Brain ◽  
Sympathetic Nervous System Activation

Abstract The brain’s relationship to essential hypertension is primarily understood to be that of an end-organ, damaged late in life by stroke or dementia. Emerging evidence, however, shows that heightened blood pressure (BP) early in life and prior to traditionally defined hypertension, relates to altered brain structure, cerebrovascular function, and cognitive processing. Deficits in cognitive function, cerebral blood flow responsivity, volumes of brain areas, and white matter integrity all relate to increased but prehypertensive levels of BP. Such relationships may be observed as early as childhood. In this review, we consider the basis of these relationships by examining the emergence of putative causative factors for hypertension that would impact or involve brain function/structure, e.g., sympathetic nervous system activation and related endocrine and inflammatory activation. Currently, however, available evidence is not sufficient to fully explain the specific pattern of brain deficits related to heightened BP. Despite this uncertainty, the evidence reviewed suggests the value that early intervention may have, not only for reducing BP, but also for maintaining brain function.

scholarly journals Hockey Concussion Education Project, Part 2. Microstructural white matter alterations in acutely concussed ice hockey players: a longitudinal free-water MRI study

2014 ◽  
Vol 120 (4) ◽  
pp. 873-881 ◽  
Author(s):  
Ofer Pasternak ◽  
Inga K. Koerte ◽  
Sylvain Bouix ◽  
Eli Fredman ◽  
Takeshi Sasaki ◽  
...  
Keyword(s):  
White Matter ◽  
Extracellular Space ◽  
Axonal Injury ◽  
Free Water ◽  
Ice Hockey ◽  
Microstructural Alterations ◽  
Hockey Players ◽  
Before And After ◽  
The Brain

Object Concussion is a common injury in ice hockey and a health problem for the general population. Traumatic axonal injury has been associated with concussions (also referred to as mild traumatic brain injuries), yet the pathological course that leads from injury to recovery or to long-term sequelae is still not known. This study investigated the longitudinal course of concussion by comparing diffusion MRI (dMRI) scans of the brains of ice hockey players before and after a concussion. Methods The 2011–2012 Hockey Concussion Education Project followed 45 university-level ice hockey players (both male and female) during a single Canadian Interuniversity Sports season. Of these, 38 players had usable dMRI scans obtained in the preseason. During the season, 11 players suffered a concussion, and 7 of these 11 players had usable dMRI scans that were taken within 72 hours of injury. To analyze the data, the authors performed free-water imaging, which reflects an increase in specificity over other dMRI analysis methods by identifying alterations that occur in the extracellular space compared with those that occur in proximity to cellular tissue in the white matter. They used an individualized approach to identify alterations that are spatially heterogeneous, as is expected in concussions. Results Paired comparison of the concussed players before and after injury revealed a statistically significant (p < 0.05) common pattern of reduced free-water volume and reduced axial diffusivity and fractional anisotropy following elimination of freewater. These free-water–corrected measures are less affected by partial volumes containing extracellular water and are therefore more specific to processes that occur within the brain tissue. Fractional anisotropy was significantly increased, but this change was no longer significant following the free-water elimination. Conclusions Concussion during ice hockey games results in microstructural alterations that are detectable using dMRI. The alterations that the authors found suggest decreased extracellular space and decreased diffusivities in white matter tissue. This finding might be explained by axonal injury and/or by increased cellularity of glia cells. Even though these findings in and of themselves cannot determine whether the observed microstructural alterations are related to long-term pathology or persistent symptoms, they are important nonetheless because they establish a clearer picture of how the brain responds to concussion.

Head Kinematics by Contact Scenarios in Youth Ice Hockey

Neurology ◽  
2020 ◽  
Vol 95 (20 Supplement 1) ◽  
pp. S1.1-S1
Author(s):  
Abigail Swenson ◽  
Logan Miller ◽  
Jillian Urban ◽  
Joel Stitzel
Keyword(s):  
Rotational Velocity ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Contact Sports ◽  
Head Impacts ◽  
Rigorous Study ◽  
Improving Accuracy ◽  
Impact Events

ObjectiveThe objective of this pilot study was to characterize head impact exposure in a sample of youth boys' ice hockey using a novel instrumented mouthpiece, improving accuracy.BackgroundFrom 2010 to 2018 youth ice hockey saw a 15% increase in participation, despite growing concerns for concussion risk in contact sports. While contact sports with similar rates of concussion have been subjected to rigorous study, head impact exposure in youth ice hockey has been largely underexplored. Existing youth studies have utilized helmet-mounted sensors, which are associated with error due to poor coupling with the skull.Design/MethodsCustom mouthpieces containing a tri-axial accelerometer and gyroscope were fit to seven enrolled athletes, and monitored during practices and games throughout the season. Linear acceleration and rotational velocity of the head were recorded for 60 ms when 5 g was exceeded on any axis for at least 3 ms. Time-synchronized film was reviewed to identify the contact scenario and head contact. Summary statistics of kinematics were calculated by scenario and presence of head contact.ResultsA total of 465 events were recorded over 25 weeks. Of these events 25% involved head contact; 92% of all contact scenarios were board checks, falls, or ice checks. Events involving head contact (i.e., head impacts) had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 8.1 [30.9] g, 7.9 [20.2] rad/s, and 614 [2673] rad/s2, respectively. Events not involving head contact had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 6.6 [43.8] g, 6.5 [17.5] rad/s, and 455 [4115] rad/s2, respectively.ConclusionsThe majority of the recorded events could be classified as board checks, falls, or ice checks. Median peak kinematics were higher for head impacts than non-head impact events. In contrast, 95th percentile linear and angular accelerations were greater for impacts not involving head contact.

scholarly journals A prospective study of physician-observed concussion during a varsity university hockey season: metabolic changes in ice hockey players. Part 4 of 4

2012 ◽  
Vol 33 (6) ◽  
pp. E4 ◽  
Author(s):  
Emilie Chamard ◽  
Hugo Théoret ◽  
Elaine N. Skopelja ◽  
Lorie A. Forwell ◽  
Andrew M. Johnson ◽  
...  
Keyword(s):  
Prospective Study ◽  
Diffusion Tensor ◽  
Metabolic Changes ◽  
Observer Design ◽  
Ice Hockey ◽  
Future Research ◽  
Prospective Clinical Study ◽  
Head Impacts ◽  
Hockey Players ◽  
A Prospective Study

Object Despite negative neuroimaging findings using traditional neuroimaging methods such as MRI and CT, sports-related concussions have been shown to cause neurometabolic changes in both the acute and subacute phases of head injury. However, no prospective clinical study has used an independent physician-observer design in the monitoring of these changes. The objective of this study was to evaluate the effects of repetitive concussive and sub-concussive head impacts on neurometabolic concentrations in a prospective study of two Canadian Interuniversity Sports (CIS) ice hockey teams using MR spectroscopy (MRS). Methods Forty-five ice hockey players (25 men and 20 women) participated in this study. All participants underwent pre- and postseason MRI, including spectroscopy imaging, using a 3-T MRI machine. The linear combination model was used to quantify the following ratios: glutamate/creatine-phosphocreatine (Cr), myoinositol/Cr, and N-acetylaspartate (NAA)/Cr. Individuals sustaining a medically diagnosed concussion were sent for MRI at 72 hours, 2 weeks, and 2 months after injury. Results No statistically significant differences were observed between athletes who were diagnosed with a concussion and athletes who were not clinically diagnosed as sustaining a concussion. Although no statistically significant longitudinal metabolic changes were observed among athletes who were diagnosed with a concussion, the results demonstrated a predictable pattern of initial impairment, followed by a gradual return to ratios that were similar to, but lower than, baseline ratios. No significant pre- to postseason changes were demonstrated among men who were not observed to sustain a concussion. However, a substantively significant decrease in the NAA/Cr ratio was noted among the female hockey players (t(13) = 2.58, p = 0.02, η2 = 0.34). Conclusions A key finding in this study, from the standpoint of future research design, is the demonstration of substantively significant metabolic changes among the players who were not diagnosed with a concussion. In addition, it may explain why there are few statistically significant differences demonstrated between players who were diagnosed with a concussion and players who were not diagnosed with a concussion (that is, the potency of the independent variable was diminished by the fact that the group of players not diagnosed with a concussion might be better described as a subgroup of the players who may have sustained a concussion but were not observed and diagnosed with a concussion). This result suggests that definitions of concussion may need to be revisited within sports with high levels of repetitive subconcussive head impacts. Future analysis of these data will examine the relationships between the modes of MRI (diffusion tensor imaging, MRS, and susceptibility-weighted MR imaging) used in this study, along with other more sensitive evaluative techniques. This type of intermodal comparison may improve the identification of concussions that were previously dependent on the unreliable self-reporting of recognized concussion symptomatology by the athlete or on poorly validated neuropsychological tests.

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