Jonathan Beckwith Simbex, Lebanon NH

1. The Biomechanics of Head Impact Lessons from Helmet Sensors Jonathan Beckwith Simbex, Lebanon NH

2. Disclosure Statement Simbex receives support to conduct research from the National Institutes of Health (NIH), the Centers for Disease Control (CDC), and the National Operating Committee on Standards for Athletic Equipment (NOCSAE). As an employee of Simbex, I have the potential to financially benefit from the sale or licensing of the HIT System, the instrument used to collect the biomechanical data reported in his presentation.

3. Learning Objectives • At the end of this session, participants will be able to: • Define Head Impact Exposure (HIE) • Identify the methods for collecting and analyzing HIE data recorded during contact sports • Describe the similarities and differences in HIE sustained by athletes participating in different sports and at different skill levels within those sports • Convey how concussion prevention and detection can be improved by analyzing the relationship between head impact exposure and injury

4. Exposure to Repetitive Head ImpactsProblem Statement OVER-EXPOSURE: There is "growing and convincing evidence" that repetitive concussive and subconcussive hits to the head…lead to a degenerative brain disease known as chronic traumatic encephalopathy. Robert Cantu, MD, co-director of Boston University's Center for the Study of Traumatic Encephalopathy UNDER-REPORTING: “More than 50% of concussions go unreported by the athlete.” Michael McCrae, Clinical Journal of Sports Medicine 2004 • MISS-UNDERSTANDING: • “Why don’t they just build better helmets?” • “Maybe the solution is for players NOT to wear helmets?” Comments section from EVERY concussion-related article since the invention of the internet

5. Solving an Injury ProblemUsing Biomechanics to Help Athletes Reduce the Incidence of Injury Shoulder and Elbow Injury • Pitch Counts: Frequency • Little League: Mandated • Major Leagues/ NCAA: Not mandated, but managed carefully by many • Anterior Cruciate Ligament • Gait analysis / training • Neuromuscular training • Prophylactic bracing • Repetitive Brain Trauma • Awareness • Tackling Technique • Equipment • ???

6. What is the mechanism of “injury”

7. History of Brain Trauma BiomechanicsA Rapidly Changing Playing Field

8. Laboratory Reconstruction of Impact • Do laboratory experiments replicate what is happening on the field? • Human physiology • Human response • Sequence of multiple impact events

9. What does a 100 g hit look like… in the lab?

10. Sporting Fields: A Living Laboratory • Concussions are a significant health care issue • Estimated 1.6 - 3.8 million sports-related concussions annually in the United States 1 • Identification remains challenging • More than 50% of concussions go unreported by the athlete 2 • Signs and symptoms may not be observed, resulting in continued play (delayed dx) 3 • Instrumented helmets used since 2003 • Defined Head Impact Exposure (HIE) for contact sports: Frequency, Location, Severity 4 1 Langlois et al., J of Head Trauma Rehabil (2006) 2 McCrea et al., Clin J Sport Med (2004) 3 Duhaime et al., J of Neurology (in review) 4 Crisco et al., J of Biomech (2011)

11. Monitor: • Activities in real-time • Player impact history • Enable Improvements: • Protective Equipment • Rules and Regulation • Public Policy • Return to action decisions • Analyze: • Identify MBTI injury mechanisms Monitoring Head Impacts In Sports Head Impact Telemetry (HIT) System used to record on-field head impact exposure during helmeted activities Development of the Head Impact Telemetry System was funded in part by the National Institutes of Health – SBIR R44HD40473, R01HD048638

12. Instrumented Helmets Technology Components • 6 single-axis accelerometers positioned against the head • Real-time, on-field data collection • Provides large database of head impacts for analysis

13. Head (not Helmet) Acceleration • HMAS (head-mounted accelerometer system) • Decouples sensors from helmet and insures consistent head/sensor contact Courtesy: Virginia Tech Manoogian et al. Biomedical Sciences Instrumentation (2006)

14. What does a 100 g hit look like … on the field? Video footage provided and permission granted to replay by the University of Oklahoma Athletic Department.

15. Biomechanical Basis for mTBI Funded By: NIH: RO1HD048638, R01NS055020 CDC: R01CE001254 NOCSAE: 07-04

16. Head Impact Biomechanics in SportsWhat have we learned? • What are there differences in Head Impact Exposure (HIE) for different athlete populations • How do measures of HIE correlate with cases of diagnosed concussion – is there an “injury threshold”? • Is there an association between HIE and signs and symptoms of concussion?

17. HIT System Use in FootballData Recorded from Instrumented Players • 9 Years on-field data collection (2003 – 12) • 1,900,000+ recorded head impacts • All levels of play • Grade School: 6 teams • High School: 19 teams • NCAA: 13 teams • Pro (CFL/NFL): 2 teams

18. HIT System Use in Ice HockeyData Recorded from Instrumented Players • 6 Years on-ice data collection (2006 – 2011) • 90,000+ recorded head impacts (through 2011 season) • Levels of Play (teams) • Junior: Female (n =1), Male (n = 4) • High School: Female (n=1), Male (n =1) • NCAA: Female (n = 2), Male (n = 2)

19. Head Impact Exposure (HIE) ProfilePrimary Measures of Interest Impact Frequency # of head impacts # of head impacts > 50th, > 95th percentile (i.e. # of high magnitude impacts) Impact Location Continuous: Azimuth, Elevation Front, Left, Right, Back, Top Impact Severity Peak Linear Acceleration (g) Peak Rotational Acceleration (rad/s2) GSI, HIC, DeltaV Crisco et al., Journal of Biomechanical Engineering (2004) Chu et al., World Congress of Biomechanics (2006)

20. HIE: Impact FrequencyNumber of head impacts per season • ~10% of all college football players sustain > 1000 impacts in a season1 • Individual football players with 2,000+ head impacts in a single season • Football players sustain > 3x impacts in games than practices • Impact frequency related to playing position • Male college hockey players sustain 2x more head impacts than females2 1 Crisco et al., J Athletic Training (2010) 2 Brainard et al., Med & Science in Sports and Exercise (2011)

21. HIE: Impact LocationFootball and Ice Hockey • Football 1 • Impact location dependent on player position • Linear acceleration highest for Top impacts • Rotational acceleration highest for Front and Back • Ice Hockey 2,3 • Most frequent to Front (30%) and Back (33%) • Similar across gender within sport • Highest severity (Top 1% linear acc.) occur to the Back of the head 1 Crisco et al., J Athletic Training (2010) 2 Brainard et al., Med & Science in Sports and Exercise (2011) 3 Gwin et al., Journal of ASTM (2009)

22. HIE: Impact Severity Collegiate Football • Impacts skewed toward lower severity • 50% of all impacts < 20.0g and 1,187rad/s2 • Distribution of impact severity does not significantly change between games and practices Crisco et al., Journal of Applied Biomechanics (2011)

23. HIE: Impact Severity:Men’s and Women’s Collegiate Hockey • Males sustain impacts resulting in higher linear and angular acceleration than females • Male hockey players are: • 1.3x more likely to sustain an impact > 100 g • 1.9x more likely to sustain an impact > 5,000 rad/s2 Brainard et al. Med Sci Sports Exerc (2011)

24. Head Impact Biomechanics in SportsWhat have we learned? • What are there differences in Head Impact Exposure (HIE) for different athlete populations • How do measures of HIE correlate with cases of diagnosed concussion – is there an “injury threshold”? • Is there an association between HIE and signs and symptoms of concussion?

25. Diagnosed Concussion Events120+ diagnosed concussions recorded with HIT System Number of impacts higher on concussion days Dx-Day: 21.0 [12.0 – 36.8] Non Dx-Day: 13.8 [9.4 – 18.9] Occur most frequently to the Front Front (46%), Top (25%), Side (16%), Back (13%) Mean magnitude > top 0.5% of all impacts sustained 103 ± 34 g > 8,000 impacts with higher magnitude NOT associated with injury …what are we missing?? Beckwith et al., FIC on Traumatic Brain Injury (2011) Beckwith et al., World Congress of Brain Injury (2012) Beckwith et al. Med Sci Sports Exerc (in review)

26. Diagnosed Concussion EventsOne-size does NOT fit all!! Athlete #1 - Immediate Diagnosis: “Player was hit on the right foreheadby opposing player while running with the ball. In the same motion, player was taken to the ground where the right side of his head impact the ground. LOC occurredbut duration was undocumented. Emergency transport via spine board and local EMS.” Athlete #2 - Delayed Diagnosis: “Athlete reports that legs swept out from underneath her. She fell backward and hit her head on the ice. She got up and continued to play, noting a headache at the time but did not report the injury. She did not report anything at all until 4 hours post-game at which time she had a headache, nausea, and was feeling dizzy and mentally foggy.” 54% of cases in current study have delayed diagnosis! Beckwith et al., FIC on Traumatic Brain Injury (2011) Beckwith et al., World Congress of Brain Injury (2012) Beckwith et al. Med Sci Sports Exerc (in press)

27. Number of Head ImpactsImmediate vs. Delayed Diagnosis • 2x more head impacts sustained prior to Delayed Dx • Delayed: 32.2 ± 24.9 • Immediate: 16.5 ± 15.1 • Similar trend for ≤ 7 days prior to injury • Players sustain more head impacts on days of delayed diagnosis * * * Denotes statistical significance (Kruskal-Wallis, α = 0.05) Beckwith et al., World Congress of Brain Injury (2012) Beckwith et al. Med Sci Sports Exerc (in press)

28. Magnitude of Head ImpactsImmediate vs. Delayed Diagnosis p = 0.011; Kruskal-Wallis (α = 0.05) p = 0.284; Kruskal-Wallis (α = 0.05) • Kinematic measures derived from linear acceleration significantly higher for impacts resulting in immediate diagnosis (p < 0.05) • No statistical difference in impact location (p=0.19) Beckwith et al., World Congress of Brain Injury (2012) Beckwith et al. Med Sci Sports Exerc (in press)

29. Head Impact Biomechanics in SportsWhat have we learned? • What are there differences in Head Impact Exposure (HIE) for different athlete populations • How do measures of HIE correlate with cases of diagnosed concussion – is there an “injury threshold”? • Is there an association between HIE and signs and symptoms of concussion?

30. Impact Exposure & Clinical Outcome Head Impact Profile Magnitude Direction Incidence Frequency FE Model Subject-Specific Theoretical Prediction of Injury Outcome Measures Symptomology Balance ImPACT NP Battery Brain Physiology fMRI DTI

31. Un-Diagnosed Concussion?Cognitive Testing Indicates Potential Under-reporting % of Athletes with Abnormal Cognitive Decline Compared to Baseline • Athletes exposed to head contact but not diagnosed w/ concussion • 52% had abnormal cognitive decline (ACD) at 72hr interval • 50% at follow-up (7+ days) – still playing and having head impacts Beckwith et al. World Congress of Brain Injury (2010).

32. Head Impact Exposure Correlation with Cognitive Decline • Abnormal Cognitive Decline • Change in cognitive domain score exceeding reliable change threshold (ImPACT) • Subjects • Diagnosed with concussion • Un-diagnosed contact athletes • Un-diagnosed non-contact athletes • Outcome • Head Impact Exposure prior to cognitive testing is sensitive to abnormal cognitive decline Beckwith et al. World Congress of Brain Injury (2010).

33. Advanced Clinical Techniques Subject-Specific Finite Element Brain Models segmentation meshing DTI (Anatomical Regions) Subject Specific FE Model Subject-specific MRI

34. Preliminary Results: Correlation of FE Model Predicted Strain with DTI • Methods • 10 cases of diagnosed concussion • Subject specific model (DSSM) based on players MR image • Model Input:10 impacts recorded prior to concussion • Measure of interest: Mean and Max strain and strain rate correlated with fractional anisotropy (FA) • ROI: Corpus Callosum • Mean and Max strain and strain rate were correlated with fractional anisotropy (FA) Overlay of max map in Corpus Callosum with FA (change in FA after concussion in parenthesis) McAllister et al. Annals of Biomedical Engineering (2011)

35. On-Field Measurement of BiomechanicsWhat Have We Learned So Far? • Expanded knowledge base of impacts in the field • How do previously established mTBI thresholds translate to on-field data • Differences in sub-concussive impact distributions • Intra-sport (position groups, skill level, etc.) • Inter-sport (football, hockey, boxing, etc.) • Inter-gender (boxing, hockey) • Measures of Head Impact Exposure • Sensitive to diagnosed injury • NOT specific to diagnosis injury • Head Impact Exposure relative to signs / symptoms of injury • Diagnosis of concussion may be too variable • Need to correlate with less subjective outcome measures

36. Solving an Injury ProblemUsing Biomechanics to Help Athletes Reduce the Incidence of Injury Shoulder and Elbow Injury • Pitch Counts: Frequency • Little League: Mandated • Major Leagues/ NCAA: Not mandated, but managed carefully by many • Anterior Cruciate Ligament • Gait analysis / training • Neuromuscular training • Prophylactic bracing • Repetitive Brain Trauma • Awareness • Tackling Technique • Equipment • Rule Changes • Relevant Standards • HIE monitoring

37. Practical Outcomes of Head Impact Monitoring Research • Rule Changes • Ivy League mandates non-contact practice (Fall 2011) • Pop Warner implements rule to limit practice contact (Beginning Fall 2012) • Improved Helmet Testing • Virginia Tech develops STAR rating system for football helmets based on HIE data (Spring 2011) • STAR results publically available 1 • Consumers can now compare helmet performance • Injury Awareness • Sports Legacy Institute urges youth sports organizations to implement a “HIT Count” for all athletes2 1 http://www.sbes.vt.edu/nid.php 2 http://www.sportslegacy.org/

38. "An Ounce of Prevention, is Worth a Pound of Cure" – Ben Franklin

39. Acknowledgements • Funding • National Institutes of Health/CDC – R01HD048638, R44HD040473, R01NS055020, R01CE001254 • Riddell Sports; Easton-Bell Sports • National Operating Committee on Standards for Athletic Equipment (NOCSAE) Simbex – Bustin’ Myths since the year 2000! • Research Partners • Brown University: Trey Crisco, PhD, and Staff • Brown Athletics: Russell Fiore, and Staff • Dartmouth Medical School: Thomas McAllister, MD; Tina Duhaime, MD; Art Maerlander, PhD; Laura Flashman, PhD; Jamie Ford, PhD; Songbai Ji, PhD; and Staff • Dartmouth Athletics – Jeff Frechette, Tracy Poro, and Staff • Virginia Tech: Stefan Duma, PhD; Gunnar Brolinson, DO; and Staff • Simbex: Rick Greenwald, PhD, Jeff Chu, Jonathan Beckwith, and Staff • University of North Carolina: Kevin Guskiewicz, PhD, and Jason Mihalik, PhD, and many others • University of Oklahoma: Scott Anderson, ATC, and Brock Schnebel, MD • University of Illinois Champaign: Steve Broglio, PhD