Subconcussive Head Impacts and Neurocognitive Function Over 3 Seasons of Youth Football

Objective: To determine the association between repetitive subconcussive head impacts and neurobehavioral outcomes in youth tackle football players. Methods: Using helmet-based sensors, we measured head impacts for 3 consecutive seasons of play in 29 male players age 9-11. Cumulative impact g’s were calculated. Players completed a battery of outcome measures before and after each season, including neuropsychological testing, vestibular-ocular sensitivity, and self- and parent-reported measures of symptoms and attention-deficit hyperactivity disorder (ADHD). Results: Average cumulative impact over 3 seasons was 13 900 g. High-intensity hits predicted worse change for self-reported social adjustment ( P = .001). Cumulative impact did not predict change in any of the outcome measures. History of ADHD, anxiety, and depression predicted worse change for self-reported symptoms and social adjustment, independent of head impacts. When players were stratified into 3 groups based on cumulative impact across all 3 seasons, differences in outcome measures existed prior to the start of the first season. These differences did not further increase over the course of the 3 seasons. Conclusion: Over 3 consecutive seasons of youth tackle football, we found no association between cumulative head impacts and neurobehavioral outcomes. Larger sample sizes and longer follow-up times would further assist in characterizing this relationship.

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Repetitive Head Impacts in Youth Football: Description and Relationship to White Matter Structure

Sports Health A Multidisciplinary Approach ◽

10.1177/1941738119865264 ◽

2019 ◽

Vol 11 (6) ◽

pp. 507-513 ◽

Cited By ~ 3

Author(s):

Kurt J. Nilsson ◽

Hilary G. Flint ◽

Yong Gao ◽

Leslie Kendrick ◽

Steve Cutchin ◽

...

Keyword(s):

White Matter ◽

Diffusion Tensor ◽

Brain Magnetic Resonance Imaging ◽

The Body ◽

Football Players ◽

Head Impacts ◽

Number Magnitude ◽

Youth Football ◽

Total Magnitude ◽

Tackle Football

Background: Few studies have examined white matter with diffusion tensor imaging in 8- to 12-year-old collision sport (CS) athletes. Hypothesis: Youth CS athletes will demonstrate change in brain fractional anisotropy (FA) after a season of CS compared with an age-matched noncollision sport (NCS) cohort, and the number, magnitude, and location of hits will correlate with changes in the brain determined via FA for CS athletes. Study Design: Prospective cohort study. Level of Evidence: Level 3. Methods: Thirty-five 8- to 12-year-old males in a youth tackle football league (CS) and 12 males from local swim teams (NCS) were recruited. Participants underwent brain magnetic resonance imaging with FA before and after the football season. Number, magnitude, and direction of head impacts were recorded for CS participants throughout the season. Results: A total of 1905 hits were recorded in the CS group for the season, 341 (17.9%) collected during 7 games and 1564 (82.1%) observed during 31 practices. No significant interaction between group (CS and NCS) and time (pre- and postseason) was observed for FA ( P > 0.05). Correlation analysis revealed a significantly positive and moderate relationship between increase of left cingulate cortex (CgC) FA from pre- to postseason and the total magnitude of lateral head impacts ( r = 0.40; P = 0.03). Conclusion: There was no significant change in FA measurement of white matter integrity in a cohort of 8- to 12-year-old males after a season of youth football, nor was any difference detected in FA between youth football players and an age-matched cohort of swimmers. There was a significant correlation between total magnitude of hits sustained by youth football players and an increase in FA in the left CgC; whether this is adaptive or pathologic remains unknown. Clinical Relevance: These data can be used within the body of knowledge to counsel patients regarding the known risks of youth tackle football regarding brain health.

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Head impact burden and change in neurocognitive function over 2 seasons of youth football participation

Neurology ◽

10.1212/01.wnl.0000550688.47301.be ◽

2018 ◽

Vol 91 (23 Supplement 1) ◽

pp. S27.1-S27

Author(s):

Sean C. Rose ◽

Keith Yeates ◽

Matthew T McCarthy ◽

Darren R Fuerst ◽

Patrick Ercole ◽

...

Keyword(s):

High School ◽

Primary School ◽

Test Performance ◽

High Intensity ◽

Behavioral Adjustment ◽

Head Impact ◽

Cumulative Impact ◽

Change Scores ◽

Head Impacts ◽

Tackle Football

ObjectiveTo determine the association of repetitive sub-concussive head impacts with neurocognitive outcomes in primary school and high school tackle football players.MethodsWe conducted a prospective cohort study of 35 primary school players age 9–12 and 20 high school players age 15–18 who each participated in 2 consecutive seasons of tackle football from 2016 to 2017. Helmet-based sensors were used to record head impacts during contact practices and games, which were summed as a cumulative impact for the 2 football seasons. Players were also divided into high intensity and low intensity groups based on whether they sustained high g-force impacts in both seasons. Players completed assessments on a variety of outcomes before the 2016 season and after the 2017 season: neuropsychological test performance, symptom ratings, vestibular-ocular function, balance, parent-completed ADHD symptoms, and self-reported behavioral adjustment.ResultsAverage cumulative impact was 6,920 (SD 4,553) g-forces combined for the 2 seasons and did not differ between age groups (p = 0.66). Twenty-one players (38%) were classified as high intensity based on individual impacts. After correcting for multiple comparisons, neither cumulative impact nor impact intensity predicted change scores from pre-2016 season to post-2017 season on any outcome measures. Instead, younger age group and history of ADHD predicted worse change scores on several cognitive measures and ADHD symptom reporting.ConclusionsOver 2 consecutive seasons of primary and high school tackle football participation, cumulative head impact burden and intensity of impacts were not found to be associated with changes in cognition, balance, vestibular-ocular function, or behavioral adjustment.

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Role of subconcussion in repetitive mild traumatic brain injury

Journal of Neurosurgery ◽

10.3171/2013.7.jns121822 ◽

2013 ◽

Vol 119 (5) ◽

pp. 1235-1245 ◽

Cited By ~ 237

Author(s):

Julian E. Bailes ◽

Anthony L. Petraglia ◽

Bennet I. Omalu ◽

Eric Nauman ◽

Thomas Talavage

Keyword(s):

Diffusion Tensor ◽

Chronic Traumatic Encephalopathy ◽

Neuropsychological Testing ◽

Axonal Injury ◽

Laboratory Data ◽

Neurological Dysfunction ◽

Neurological Injury ◽

Cumulative Impact ◽

Contact Sports ◽

Head Impacts

Research now suggests that head impacts commonly occur during contact sports in which visible signs or symptoms of neurological dysfunction may not develop despite those impacts having the potential for neurological injury. Recent biophysics studies utilizing helmet accelerometers have indicated that athletes at the collegiate and high school levels sustain a surprisingly high number of head impacts ranging from several hundred to well over 1000 during the course of a season. The associated cumulative impact burdens over the course of a career are equally important. Clinical studies have also identified athletes with no readily observable symptoms but who exhibit functional impairment as measured by neuropsychological testing and functional MRI. Such findings have been corroborated by diffusion tensor imaging studies demonstrating axonal injury in asymptomatic athletes at the end of a season. Recent autopsy data have shown that there are subsets of athletes in contact sports who do not have a history of known or identified concussions but nonetheless have neurodegenerative pathology consistent with chronic traumatic encephalopathy. Finally, emerging laboratory data have demonstrated significant axonal injury, blood-brain barrier permeability, and evidence of neuroinflammation, all in the absence of behavioral changes. Such data suggest that subconcussive level impacts can lead to significant neurological alterations, especially if the blows are repetitive. The authors propose “subconcussion” as a significant emerging concept requiring thorough consideration of the potential role it plays in accruing sufficient anatomical and/or physiological damage in athletes and military personnel, such that the effects of these injuries are clinically expressed either contemporaneously or later in life.

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Top Ten Reasons Why All Athletes Need to have Neuropsychological Testing

10.47363/jpsrr/2019(1)101 ◽

2019 ◽

pp. 1-2

Author(s):

Michael F Shaughnessy ◽

Keyword(s):

Chronic Traumatic Encephalopathy ◽

Neuropsychological Testing ◽

Head Injuries ◽

Return To Play ◽

Research Journal ◽

Post Test ◽

Control And Prevention ◽

History Of ◽

Tackle Football

Currently, we are more and more aware of head injuries, concussion and the risks and dangers of athletes being exposed to long term risk and injury.Twenty years or so ago, coaches relied on side line assessment to decide as to whether an athlete who“has had his/her bells rung” should return to play. Currently however, there is much more sophisticated sideline assessment (such as Impact) and other laptop instruments. There are many, many reasons why athletes should undergo pre-and post-test assessment as well as sideline assessment. These will be summarily discussed. These issues have also been discussed by:Arginteanu (2019) and others have clearly specified the need to be concerned and observant regardingthe concept of return to play and even return to the classroom. Hernandez, Giordano, Goubran, Parivash, Grant, Zeineh and Camarillo (2019) have discussed sports related concussions and Corman, Adame, Tsa, Ruston, Beaumont, Kamrath, Liu, Posteher, Tremblayand van Raalt, (2019) have published on sports related concussions. Rose, Yeates, Nguyen, McCarthy, Ercole, Pizzimenti, (2019)have written on youth tackle football. Engleman (2013) writing in The Rotarian pp 27-30 suggests that “youth football leagues should require coaches and encourage all parents, to take the “Heads IUP” training course available at www.cdc.gov. The web site of the U.S. Centers for Disease Control and Prevention” There is much concern about CTE (Chronic traumatic encephalopathy- which is a progressive degenerative disease of the brain. This is usually discerned in individuals who have some type of history of repetitive brain trauma or injury. This could include soccer, basketball, baseball, softball (at least many players DO wear helmets) and wrestling (in terms of wrestling, players do wear protective devices for their ears, but still may suffer concussions and head injuries. Shaughnessy and Laman (2012) have provided an excellent review of evidence based intervention and treatment/rehabilitation of traumatic brain injury. This was published in the Research Journal in Organizational Psychology and Educational Studies and is a serious review of the literature in this realm.

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Gastrocnemius Stretching Program: More Effective in Increasing Ankle/Rear-Foot Dorsiflexion When Subtalar Joint Positioned in Pronation Than in Supination

Journal of Sport Rehabilitation ◽

10.1123/jsr.2014-0191 ◽

2015 ◽

Vol 24 (3) ◽

pp. 307-314 ◽

Cited By ~ 3

Author(s):

Marie A. Johanson ◽

Megan Armstrong ◽

Chris Hopkins ◽

Meghan L. Keen ◽

Michael Robinson ◽

...

Keyword(s):

Outcome Measures ◽

Subtalar Joint ◽

Mixed Model ◽

Controlled Trial ◽

Cumulative Trauma ◽

Mixed Model Anova ◽

Main Effect ◽

Before And After ◽

History Of ◽

Analysis System

Context:Stretching exercises are commonly prescribed for patients and healthy individuals with limited extensibility of the gastrocnemius muscle.Objective:To determine if individuals demonstrate more dorsiflexion at the ankle/rear foot and less at the midfoot after a gastrocnemius-stretching program with the subtalar joint (STJ) positioned in supination compared with pronation.Design:Randomized controlled trial.Setting:Biomechanical laboratory.Participants:22 volunteers with current or recent history of lower-extremity cumulative trauma and gastrocnemius tightness (10 women and 4 men, mean age 28 y) randomly assigned to stretching groups with the STJ positioned in either pronation (n = 11) or supination (n = 11).Intervention:3-wk home gastrocnemius-stretching program using a template to place the subtalar joint in either a pronated or a supinated position.Main Outcome Measures:A 7-camera Vicon motion-analysis system measured ankle/rear-foot dorsiflexion and midfoot dorsiflexion of all participants during stretching with the STJ positioned in both pronation and supination before and after the 3-wk gastrocnemius-stretching program.Results:A 2-way mixed-model ANOVA revealed a significant interaction (P = .019). At posttest, the group who performed the 3-week stretching program with the STJ positioned in pronation demonstrated more increased ankle/rear-foot dorsiflexion when measured with the STJ in pronation than the group who performed the 3-wk stretching program with the STJ positioned in supination. No significant main effect of stretching group or interaction for dorsiflexion at the midfoot was detected (P = .755 and P = .820, respectively).Conclusion:After a 3-wk gastrocnemius-stretching program, when measuring dorsiflexion with the STJ positioned in supination, the participants who completed a 3-wk gastrocnemius stretching program with the STJ positioned in pronation showed more increased dorsiflexion at the ankle/rear foot than participants who completed the stretching program with the STJ positioned in supination.

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Practice type effects on head impact in collegiate football

Journal of Neurosurgery ◽

10.3171/2015.5.jns15573 ◽

2016 ◽

Vol 124 (2) ◽

pp. 501-510 ◽

Cited By ~ 33

Author(s):

Bryson B. Reynolds ◽

James Patrie ◽

Erich J. Henry ◽

Howard P. Goodkin ◽

Donna K. Broshek ◽

...

Keyword(s):

National Collegiate Athletic Association ◽

Collegiate Athletes ◽

Head Impact ◽

Football Players ◽

Rotational Acceleration ◽

Event Type ◽

Cumulative Impact ◽

Head Impacts ◽

Average Impact ◽

Collegiate Football

OBJECT This study directly compares the number and severity of subconcussive head impacts sustained during helmet-only practices, shell practices, full-pad practices, and competitive games in a National Collegiate Athletic Association (NCAA) Division I-A football team. The goal of the study was to determine whether subconcussive head impact in collegiate athletes varies with practice type, which is currently unregulated by the NCAA. METHODS Over an entire season, a cohort of 20 collegiate football players wore impact-sensing mastoid patches that measured the linear and rotational acceleration of all head impacts during a total of 890 athletic exposures. Data were analyzed to compare the number of head impacts, head impact burden, and average impact severity during helmet-only, shell, and full-pad practices, and games. RESULTS Helmet-only, shell, and full-pad practices and games all significantly differed from each other (p ≤ 0.05) in the mean number of impacts for each event, with the number of impacts being greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. The cumulative distributions for both linear and rotational acceleration differed between all event types (p < 0.01), with the acceleration distribution being similarly greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. For both linear and rotational acceleration, helmet-only practices had a lower average impact severity when compared with other event types (p < 0.001). However, the average impact severity did not differ between any comparisons of shell and full-pad practices, and games. CONCLUSIONS Helmet-only, shell, and full-pad practices, and games result in distinct head impact profiles per event, with each succeeding event type receiving more impacts than the one before. Both the number of head impacts and cumulative impact burden during practice are categorically less than in games. In practice events, the number and cumulative burden of head impacts per event increases with the amount of equipment worn. The average severity of individual impacts is relatively consistent across event types, with the exception of helmet-only practices. The number of hits experienced during each event type is the main driver of event type differences in impact burden per athletic exposure, rather than the average severity of impacts that occur during the event. These findings suggest that regulation of practice equipment could be a fair and effective way to substantially reduce subconcussive head impact in thousands of collegiate football players.

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Concussion related deficits in the general population predict impairments in varsity footballers

10.31234/osf.io/b2gxv ◽

2019 ◽

Author(s):

Clara Alexandra Stafford ◽

Bobby Stojanoski ◽

Conor Wild ◽

Danielle Brewer-Deluce ◽

Timothy D. Wilson ◽

...

Keyword(s):

General Population ◽

Inhibitory Control ◽

Population Level ◽

American Football ◽

Cognitive Tasks ◽

Football Players ◽

Head Impacts ◽

Demographic Questionnaire ◽

History Of

ObjectiveWe investigated the long-term cognitive effects of concussion in 19,261 members of the general population and a cohort of varsity American football players with a history of frequent head impacts, using tests that are known to be sensitive to small changes in performance. MethodsWe asked 19,261 participants to complete a demographic questionnaire and 12 cognitive tests measuring aspects of executive function, including inhibitory control. We compared the performance of those reporting a history of concussion (post-concussion) to those reporting no history of concussion (non-concussed) on the cognitive battery and four non-cognitive variables. We used the results of this population-level study to predict the profile of cognitive performance in varsity American football players, who completed the same cognitive tasks. ResultsPost-concussion and non-concussed participants did not differ on 11 of the 12 cognitive tasks employed. However, on a test of inhibitory control based on the classic Stroop paradigm, post-concussion participants showed accuracy-related impairments specific to the incongruent conditions of the task. Post-concussion participants reported higher levels of anxiety, depression, and trouble concentrating. An entirely independent sample of 74 varsity American football players demonstrated the same pattern of impairment: compared to healthy controls, they scored significantly lower on the test of inhibitory control but were indistinguishable from controls on the 11 other tasks.InterpretationSelf-reported concussion is not associated with long-term general effects on cognitive function. Nevertheless, those who report at least one concussion and those who expose themselves to long-term frequent sport-related head impacts, do have a modest, but statistically robust, deficit of inhibitory control.

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Exposure to Head Impacts and Cognitive and Behavioral Outcomes in Youth Tackle Football Players Across 4 Seasons

JAMA Network Open ◽

10.1001/jamanetworkopen.2021.40359 ◽

2021 ◽

Vol 4 (12) ◽

pp. e2140359

Author(s):

Sean C. Rose ◽

Keith Owen Yeates ◽

Joseph T. Nguyen ◽

Natalie M. Pizzimenti ◽

Patrick M. Ercole ◽

...

Keyword(s):

Behavioral Outcomes ◽

Football Players ◽

Head Impacts ◽

Tackle Football

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REPETITIVE HEAD IMPACTS IN YOUTH FOOTBALL: DESCRIPTION AND RELATIONSHIP TO WHITE MATTER STRUCTURE

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00002 ◽

2019 ◽

Vol 7 (3_suppl) ◽

pp. 2325967119S0000

Author(s):

Kurt Nilsson

Keyword(s):

White Matter ◽

Football Players ◽

Average Weight ◽

Average Height ◽

Head Impacts ◽

Repetitive Head Impacts ◽

Number Magnitude ◽

Youth Football ◽

Total Magnitude ◽

Tackle Football

Background: A growing body of evidence has suggested that repetitive head impacts (RHIs) in collision sports produce changes in white matter tracts of athletes as detected by diffusion tensor imaging (DTI). Few studies have examined DTI in 8-12 year old collision sport (CS) athletes, compared them to non-collision sports (NCS) athletes, and correlated findings to accelerometry data. We sought to explore whether, after a single season of participation in youth football, 8-12 year old male CS athletes will: 1) have change in DTI fractional anisotropy (FA) of commonly injured brain regions, 2) have FA differences when compared to an age-matched NCS cohort, and 3) whether there is a correlation between FA and number, magnitude, and location of impacts. Methods: Thirty five 8-12 year old male participants in an organized youth tackle football league were recruited (CS) and matched with twelve 8-12 year old male participants in a local swim team (NCS). Each cohort underwent brain MRI with FA at 5 regions of interest (ROIs) before the youth football season and again immediately following the football season. CS participants’ helmets were instrumented with a force switch sensor to record number, magnitude, and direction of head impacts throughout a single season. Descriptive statistics were calculated for age, height, weight, FA values in all DTI ROIs (Anterior Corona Radiata (ACR), Cingulate Cortex (CgC), Genu of the Corpus Collosum (gCC), Posterior Limb of the Internal Capsule (pllC) and Splenium of the Corpus Collosum (SCC)), magnitude of head impact recorded by accelerometry by season, game and practice, number of hits by season, game and practice and by direction (top, side and rear). A mixed model (group by time) repeated measures MANOVA was conducted to determine if there were any differences in FA between the CS group and the NCS group from pre- to post-season. Correlation and regression analyses were carried out to determine if there was a relationship between the changes of FA from pre- to post-season and number and magnitude of head impacts in the CS group. Results: The average age of participants was: CS: 10.11 years, NCS: 10.17 years. The average height of participants was: CS: 56.89±4.06 inches; NCS: 59.92±5.00 inches (p=0.04). The average weight was: CS: 84.23±21.51 lbs; NCS: 84.75±24.04 lbs, (p>0.05). A total of 1905 hits were recorded for 34 participants in the CS group for the season, 341 (17.9% of total) collected during 7 games and 1564 (82.1% of total) observed during 31 practices. A total of 301 impacts (15.8% of total) with magnitude >= 80 g were collected. For brain ROIs investigated with FA, no significant interaction between group (CS and NCS) and time (pre to post season) was observed (p>0.05). Correlation analysis revealed a significantly positive and moderate relationship between increase of left CgC FA from pre to post season and the total magnitude of lateral head impacts (r=0.40, p=0.03). Conclusion: Our cohort of 8-12 year old male football players sustained fewer impacts when compared to prior accelerometry studies on youth football, although there was a larger number of higher force impacts recorded. There was no significant change in FA measurement of white matter integrity in our youth football players after a single football season, nor was there any difference detected in FA between youth football players and an age-matched cohort of swimmers. There was a significant correlation between total magnitude of hits sustained by youth football players during the season and an increase in FA in the left CgC. Whether this finding is adaptive or pathologic remains unclear. Significance: There is no evidence that 8-12 year old male football players sustain significant white matter changes after a single season of tackle football, although there is positive correlation of FA of the left cingulate gyrus to total magnitude of head impacts over the season.

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The Effect of Muscle Fatigue on Muscle Force-Couple Activation of the Shoulder

Journal of Sport Rehabilitation ◽

10.1123/jsr.10.4.246 ◽

2001 ◽

Vol 10 (4) ◽

pp. 246-256 ◽

Cited By ~ 4

Author(s):

Timothy J. Henry ◽

Scott M. Lephart ◽

Jorge Giraldo ◽

David Stone ◽

Freddie H. Fu

Keyword(s):

Muscle Fatigue ◽

Outcome Measures ◽

Muscle Force ◽

Glenohumeral Joint ◽

Previous History ◽

Type Design ◽

Before And After ◽

History Of ◽

Male Subjects ◽

Force Couple

Context:Muscle fatigue is an important concept in regard to the muscle function of the shoulder joint. Its effect on the muscle force couples of the glenohumeral joint has not been fully identified.Objective:To examine the effects of muscle fatigue on muscle force-couple activation in the normal shoulder.Design:Pretest, posttest.Patients:Ten male subjects, age 18–30 years, with no previous history of shoulder problems.Main Outcome Measures:EMG (area) values were assessed for the anterior and middle deltoid, subscapularis, and infraspinatus muscles during 4 dynamic stabilizing exercises before and after muscle fatigue. The exercises examined were a push-up, horizontal abduction, segmental stabilization, and rotational movement on a slide board.Results:No significant differences were observed for any of the muscles tested.Conclusions:The results of our study indicate that force-couple coactivation of the glenohumeral joint is not significantly altered after muscle fatigue.

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