Association Between Antemortem FLAIR White Matter Hyperintensities and Neuropathology in Brain Donors Exposed to Repetitive Head Impacts

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000013012
Author(s):  
Madeline Uretsky ◽  
Sylvain Bouix ◽  
Ronald J. Killiany ◽  
Yorghos Tripodis ◽  
Brett Martin ◽  
...  
Keyword(s):  
White Matter ◽  
White Matter Hyperintensities ◽  
Microvascular Disease ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Head Impacts ◽  
Repetitive Head Impacts ◽  
Pathological Correlation ◽  
Daily Function

Background and Objectives:Late neuropathologies of repetitive head impacts from contact sports can include chronic traumatic encephalopathy (CTE) and white matter degeneration. White matter hyperintensities (WMH) on fluid attenuated inversion recovery (FLAIR) MRI scans are often viewed as microvascular disease from vascular risk, but might have unique underlying pathologies and risk factors in the setting of repetitive head impacts. We investigated the neuropathological correlates of antemortem WMH in brain donors exposed to repetitive head impacts. The association between WMH, and repetitive head impact exposure and informant-reported cognitive and daily function were tested.Methods:This imaging-pathological correlation study included symptomatic deceased men exposed to repetitive head impacts. Donors had antemortem FLAIR scans from medical records and were without evidence of CNS neoplasm, large vessel infarcts, hemorrhage, and/or encephalomalacia. WMH were quantified using log-transformed values for total lesion volume (TLV), calculated using the lesion prediction algorithm from the Lesion Segmentation Toolbox. Neuropathological assessments included semi-quantitative ratings of white matter rarefaction, cerebrovascular disease, p-tau severity (CTE stage, dorsolateral frontal cortex), and Aβ. Among football players, years of play was a proxy for repetitive head impact exposure. Retrospective informant-reported cognitive and daily function were assessed using the Cognitive Difficulties Scale (CDS) and Functional Activities Questionnaire (FAQ). Regression models controlled for demographics, diabetes, hypertension, and MRI resolution. Statistical significance was defined as p<0.05.Results:The sample included 75 donors: 67 football players and 8 non-football contact sport athletes and/or military veterans. Dementia was the most common MRI indication (64%). Fifty-three (70.7%) had CTE at autopsy. Log-TLV was associated with white matter rarefaction (OR=2.32, 95% CI=1.03,5.24, p=0.04), arteriolosclerosis (OR=2.38, 95% CI=1.02,5.52, p=0.04), CTE stage (OR=2.58, 95% CI=1.17,5.71, p=0.02), and dorsolateral frontal p-tau severity (OR=3.03, 95% CI=1.32,6.97, p=0.01). There was no association with Aβ. More years of football play was associated with log-TLV (b=0.04, 95% CI=0.01,0.06, p=0.01). Greater log-TLV correlated with higher FAQ (unstandardized beta=4.94, 95% CI=0.42,8.57, p=0.03) and CDS scores (unstandardized beta=15.35, 95% CI=-0.27,30.97, p=0.05).Discussion:WMH might capture long-term white matter pathologies from repetitive head impacts, including those from white matter rarefaction and p-tau, in addition to microvascular disease. Prospective imaging-pathological correlation studies are needed.Classification of Evidence:This study provides Class IV evidence of associations between FLAIR white matter hyperintensities, and neuropathological changes (white matter rarefaction, arteriolosclerosis, p-tau accumulation), years of American football play, and reported cognitive symptoms in symptomatic brain donors exposed to repetitive head impacts.

scholarly journals Similar head impact acceleration measured using instrumented ear patches in a junior rugby union team during matches in comparison with other sports

2016 ◽  
Vol 18 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Doug A. King ◽  
Patria A. Hume ◽  
Conor Gissane ◽  
Trevor N. Clark
Keyword(s):  
Injury Risk ◽  
Linear Acceleration ◽  
Rugby Union ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Head Impacts ◽  
Impact Acceleration ◽  
The Impact ◽  
Rugby Players

OBJECTIVE Direct impact with the head and the inertial loading of the head have been postulated as major mechanisms of head-related injuries, such as concussion. METHODS This descriptive observational study was conducted to quantify the head impact acceleration characteristics in under-9-year-old junior rugby union players in New Zealand. The impact magnitude, frequency, and location were collected with a wireless head impact sensor that was worn by 14 junior rugby players who participated in 4 matches. RESULTS A total of 721 impacts > 10g were recorded. The median (interquartile range [IQR]) number of impacts per player was 46 (IQR 37–58), resulting in 10 (IQR 4–18) impacts to the head per player per match. The median impact magnitudes recorded were 15g (IQR 12g–21g) for linear acceleration and 2296 rad/sec2 (IQR 1352–4152 rad/sec2) for rotational acceleration. CONCLUSIONS There were 121 impacts (16.8%) above the rotational injury risk limit and 1 (0.1%) impact above the linear injury risk limit. The acceleration magnitude and number of head impacts in junior rugby union players were higher than those previously reported in similar age-group sports participants. The median linear acceleration for the under-9-year-old rugby players were similar to 7- to 8-year-old American football players, but lower than 9- to 12-year-old youth American football players. The median rotational accelerations measured were higher than the median and 95th percentiles in youth, high school, and collegiate American football players.

Behavioral Tackling Interventions Decrease Head Impact Frequency in American Football Players: A Critically Appraised Topic

2020 ◽  
pp. 1-7
Author(s):  
Ashley E. Evans ◽  
Madeline Curtis ◽  
Marguerite (Meg) Montjoy ◽  
Erica Beidler
Keyword(s):  
High School ◽  
Injury Prevention ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Clinical Question ◽  
Impact Frequency ◽  
Bottom Line ◽  
Head Impacts ◽  
Different Types

Context: The rate of sport-related concussion diagnosis has significantly increased in recent years, which has created a need for injury prevention initiatives. There have been efforts put forth by researchers and American football organizations to teach athletes how to tackle properly in order to decrease the number of subconcussive head impacts and concussions. Clinical Question: Does the implementation of a behavioral tackling intervention decrease the head impact frequency in American football players? Clinical Bottom Line: There is moderate SORT Level B evidence to support the use of behavioral tackling interventions as a means for reducing head impact frequency in football athletes. All four included studies found a significant reduction in head impacts following a behavioral tackling intervention with study findings ranging from a 26–33% reduction in impact frequency. These findings were consistent in youth, high school, and college football players and for different types of behavioral tackling interventions. Therefore, these results indicate that behavioral tackling interventions have the potential to reduce the number of head impacts sustained by American football players, which may ultimately lead to a reduction in concussion occurrence as well.

scholarly journals Age at First Exposure to Repetitive Head Impacts Is Associated with Smaller Thalamic Volumes in Former Professional American Football Players

2018 ◽  
Vol 35 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Vivian Schultz ◽  
Robert A. Stern ◽  
Yorghos Tripodis ◽  
Julie Stamm ◽  
Pawel Wrobel ◽  
...  
Keyword(s):  
American Football ◽  
Football Players ◽  
Head Impacts ◽  
Repetitive Head Impacts

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

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.

History of Chronic Traumatic Encephalopathy

2020 ◽  
Vol 40 (04) ◽  
pp. 353-358
Author(s):  
Robert C. Cantu ◽  
Charles Bernick
Keyword(s):  
Chronic Traumatic Encephalopathy ◽  
Neurological Impairment ◽  
American Football ◽  
Football Players ◽  
Long Term Effects ◽  
Public Attention ◽  
Head Impacts ◽  
Repetitive Head Impacts ◽  
History Of ◽  
Initial Description

AbstractThe long-term effects of repetitive head impacts have been recognized for close to a century. What is now referred to as chronic traumatic encephalopathy (CTE) was first described by Martland in 1928 in a series of boxers. Over the years, several important articles were published, including Critchley's 1957 report where he introduced the term “chronic traumatic encephalopathy,” Robert's study in 1969 which provided evidence of the prevalence of neurological impairment in retired fighters, and Corsellis' initial description of the pathology of CTE. However, what brought public attention to the issue of CTE in sports were the postmortem findings of CTE pathology in professional American football players, initially reported by Omalu and subsequently in a large series by McKee. There is now standardization of pathological criteria for CTE and recognition that it can be seen across all activities that involve repetitive head impacts.

scholarly journals Comparison of video-based and sensor-based head impact exposure

2017 ◽  
Author(s):  
Calvin Kuo ◽  
Lyndia Wu ◽  
Jesus Loza ◽  
Daniel Senif ◽  
Scott C. Anderson ◽  
...  
Keyword(s):  
Angular Position ◽  
Head Impact ◽  
American Football ◽  
Rear Side ◽  
Football Players ◽  
Head Impacts ◽  
Video Assessment ◽  
Impact Location ◽  
Video Observations ◽  
Time Stamps

AbstractPrevious research has sought to quantify head impact exposure using wearable kinematic sensors. However, many sensors suffer from poor accuracy in estimating impact kinematics and count, motivating the need for additional independent impact exposure quantification for comparison. Here, we equipped seven collegiate American football players with instrumented mouthguards, and video recorded practices and games to compare video-based and sensor-based exposure rates and impact location distributions. Over 50 player-hours, we identified 271 helmet contact periods in video, while the instrumented mouthguard sensor recorded 2,032 discrete head impacts. Matching video and mouthguard real-time stamps yielded 193 video-identified helmet contact periods and 217 sensor-recorded impacts. To compare impact locations, we binned matched impacts into frontal, rear, side, oblique, and top locations based on video observations and sensor kinematics. While both video-based and sensor-based methods found similar location distributions, our best method utilizing integrated linear and angular position only correctly predicted 81 of 217 impacts. Finally, based on the activity timeline from video assessment, we also developed a new exposure metric unique to American football quantifying number of cross-verified sensor impacts per player-play. We found significantly higher exposure during games (0.35, 95% CI: 0.29-0.42) than practices (0.20, 95% CI: 0.17-0.23) (p<0.05). In the traditional impacts per player-hour metric, we observed higher exposure during practices (4.7) than games (3.7) due to increased player activity in practices. Thus, our exposure metric accounts for variability in on-field participation. While both video-based and sensor-based exposure datasets have limitations, they can complement one another to provide more confidence in exposure statistics.

scholarly journals Advanced mapping of the human white matter microstructure better separates elite sports participation

2020 ◽  
Author(s):  
Bradley Caron ◽  
Daniel Bullock ◽  
Lindsey Kitchell ◽  
Brent McPherson ◽  
Derek Alexander Kellar ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Tissue ◽  
Sports Participation ◽  
Tissue Structure ◽  
Football Players ◽  
Model Parameters ◽  
Head Impacts ◽  
Repetitive Head Impacts ◽  
Brain White Matter

Collision-sport athletes, especially football players, are exposed to a higher number of repetitive head impacts. Little is known, however, regarding the effects of long-term exposure to repetitive head impacts on brain tissue structure and the locations (i.e. superficial or deep tissue structures) affected. On top of this, little is known about the effects of highly competitive, strenuous, long-term athletics on brain tissue structure. We investigated this relationship using advanced microstructural mapping techniques. Specifically, we examined the baseline differences in collegiate athletic participants by using two models of the diffusion-weighted magnetic resonance imaging signal (the Diffusion Tensor and NODDI model). DTI and NODDI parameters were mapped in both cortical and subcortical structures, as well as in the major white matter tracts. Three groups of young adults participated in our study; IU football players, cross country runners, and non-athlete students. For both models, athletes were found to have consistently higher measures of microstructure than controls. The NODDI model parameters showed stronger results indicating that it might be more sensitive to capturing differences in brain white matter tissue microstructure than the DTI model. This was the first investigation into the effects of repetitive head impacts to use an open-source data processing platform brainlife.io. Data and analyses for this study are available at https://doi.org/10.25663/brainlife.pub.14.

Repetitive head impacts in a collegiate football season: Exposure and effects

2021 ◽  
pp. 174795412110272
Author(s):  
Laura D Wilson ◽  
Rachel A Hildebrand ◽  
Trang Le ◽  
Brett A McKinney
Keyword(s):  
Reaction Time ◽  
American Football ◽  
Division I ◽  
Football Players ◽  
Short Term ◽  
Head Impacts ◽  
Repetitive Head Impacts ◽  
The Past ◽  
Acute Increase ◽  
Collegiate Football

This study describes exposure to repetitive head impacts (RHI) by player position and activity during a collegiate football season, and investigates the relationship between RHI and acute (i.e., daily and weekly) and short-term (i.e., pre- to post-season) changes in balance, reaction time, symptoms, and cognition. We recorded RHI exposure in twenty Division I collegiate American football players during a single season using the Riddell InSite system. Participants sustained 4,586 impacts (4.20% high impact, i.e., >63 g; 95.79% low impact, i.e., 20–63 g). Greatest exposure to RHI was observed in running backs and defensive ends during games, and tight ends and defensive ends during practices. Running plays and team drills placed players at greatest risk for exposure during practice. Cumulative RHI exposure across the season was associated with short-term declines in reaction time (p = 0.045), but not balance or cognition. Acute decline in balance was associated with the number of impacts sustained in the past week (p < 0.05), but not the past 24 hours (p > 0.05). Acute increase in total symptom score was also associated with the number of impacts sustained in the past week (p < 0.01), but not the past 24 hours (p > 0.05). Reaction time did not decline based on impact exposure in the past 24 hours or week. This study identifies activities and positions that may put players at risk for RHI exposure, and demonstrates that RHI sustained during the course of typical American football play by non-concussed individuals may result in small changes in balance, reaction time, and symptoms, but not cognition.

scholarly journals Disparate Associations of Years of Football Participation and a Metric of Head Impact Exposure with Neurobehavioral Outcomes in Former Collegiate Football Players

2021 ◽  
pp. 1-13
Author(s):  
Benjamin L. Brett ◽  
Amy M. Nader ◽  
Zachary Y. Kerr ◽  
Avinash Chandran ◽  
Samuel R. Walton ◽  
...  
Keyword(s):  
Sport Participation ◽  
Verbal Learning ◽  
Brief Symptom Inventory ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Structured Interviews ◽  
Head Impacts ◽  
Exposure Estimate ◽  
Neurobehavioral Outcomes

Abstract Objectives: Years of sport participation (YoP) is conventionally used to estimate cumulative repetitive head impacts (RHI) experienced by contact sport athletes. The relationship of this measure to other estimates of head impact exposure and the potential associations of these measures with neurobehavioral functioning are unknown. We investigated the association between YoP and the Head Impact Exposure Estimate (HIEE), and whether associations between the two estimates of exposure and neurobehavioral functioning varied. Methods: Former American football players (N = 58; age = 37.9 ± 1.5 years) completed in-person evaluations approximately 15 years following sport discontinuation. Assessments consisted of neuropsychological assessment and structured interviews of head impact history (i.e., HIEE). General linear models were fit to test the association between YoP and the HIEE, and their associations with neurobehavioral outcomes. Results: YoP was weakly correlated with the HIEE, p = .005, R 2 = .13. Higher YoP was associated with worse performance on the Symbol Digit Modalities Test, p = .004, R 2 = .14, and Trail Making Test-B, p = .001, R 2 = .18. The HIEE was associated with worse performance on the Delayed Recall trial of the Hopkins Verbal Learning Test-Revised, p = .020, R 2 = .09, self-reported cognitive difficulties (Neuro-QoL Cognitive Function), p = .011, R 2 = .10, psychological distress (Brief Symptom Inventory-18), p = .018, R 2 = .10, and behavioral regulation (Behavior Rating Inventory of Executive Function for Adults), p = .017, R 2 = .10. Conclusions: YoP was marginally associated with the HIEE, a comprehensive estimate of head impacts sustained over a career. Associations between each exposure estimate and neurobehavioral functioning outcomes differed. Findings have meaningful implications for efforts to accurately quantify the risk of adverse long-term neurobehavioral outcomes potentially associated with RHI.

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