Biomechanical Forces of Concussions February 20, 2013 Martin Mrazik, PhD, R.Psych. University of Alberta
Acknowledgements
The Problem
In the News The Globe and Mail (March 15, 2011): Bob Probert s brain damage a cautionary tale for today s NHLers
Head Hits at Their Worst
Concussion? A complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. McCrory et al, CJSM, 2009
Chronic Traumatic Encephalopathy
Look on the bright side For a few seconds you forgot you were a Calgary Flame
Current Challenges
Sport Concussion Hockey Canada: 550,000 + minor hockey players Hockey USA: 583,000 + minor hockey players Estimated 3.8 million sports head injuries/year (CDC, 2010) Guskiewicz (2010); 6% of college athletes NHL: Benson et al (2011, CMAJ) 1.8 concussions/1000 player hours or 7.7 % of players 70% had resolution: 7 to 10 days
Elite Hockey Concussion Study (Emery et al. 2011-2012) Calgary (17.78 concussions/100 players) Edmonton (19.16 concussions/100 players) Overall 18.17 concussions/100 players 2X previously reported rate
To tell or not to tell? Or if an athlete is injured.
The Challenge of Concussions Mrazik & Perra 2012 What would you do? Total Male Female Stop playing and tell the 143(78.6) 124(80.1) 19(70.4) coach or trainer What did you do? Total Male Female Stopped playing and told my coach or trainer 28(43.8) 22(42.3) 6(50.)
In the March 2012 Clinical Journal of Sports Medicine, 3 Richard M. Greenwald, PhD of the Thayer School of Engineering at Dartmouth College, says the best way to reduce underreporting of brain injury in sports is widespread real-time monitoring of head impact exposure (e.g. number, severity, location, and cumulative impact)
How to Measure Biomechanical Force
Biomechanical Force Pudenz & Shelden (1970 s) Primate studies using cinematography of the brain Theorized 2 types of forces causing damage to brain tissue Linear Rotational acceleration Genneralli et al (1980 s) Impact of acceleration forces in primates
Biomechanical Force National Football League (Pellman et al., 2003) Video Surveillance to reproduce biomechanical force Developed the Wayne State Tolerance Curve Relationship between physical force and head trauma
Biomechanical Force Computer generated models Lack generalizability (Guskiewicz et al., 2011) Naunheim et al. (2000) Football player (29.2g) Hockey player (35.0g) Soccer (unreliable measures) Mihalik et al (2008) 88 football players Peak impact < 20 g s
Biomechanical Force Mihalik et al. (2008) 13 fourteen year-old hockey players Peak force was < 20g s Mihalik et al. (2010) 16 fourteen year-old hockey players Anticipated had less severe impacts than unanticipated Open ice had higher force than by the boards
Current Questions/Controversies Is there a threshold of a concussion? When should a player be checked for a possible concussion? What is the outcome of multiple, high intensity hits during the course of a season? Career?
Safebrain Systems
Safebrain specs Light weight (< 8 g s); attached to outside of helmet The C.I.A. Sensor patented 3-axis accelerometer based on a powerful 16-bit microprocessor. a data-logger and real-time clock to provide time-stamped G force-readings Adjustable threshold
Safebrain Systems
Safebrain Systems
Safebrain Systems
Safebrain Systems
The Data Sample: 4 teams Alberta, Saskatchewan & Ontario 3 Boys teams, 1 Girls Team Biomechanical Data N = 11, 445 hits among 72 athletes Average season = 21 games Average of 136.26 hits per game over 15g Average = 7.57 hits/player per game; Range = 0 to 50
The Data Biomechanical Data Average G-force = 19.01 G s (total force) Average Duration = 9.93ms (Range 2ms 64ms)
The Data Heavy vs light 19.14 18.94 11.96 11.57 8.95 5.93 heavy light heavy light heavy light Frequency Duration Intensity
The First Hit
The Data 30 A Typical Hit 25 20 15 G-Force 10 5 Series1 Series2 Series3 Series4 0 1 2 3 4 5 6 7 8 9 10-5 -10-15
The Second Hit
The Data 40 Concussion 30 20 10 Series1 G-Force 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Series2 Series3 Series4-10 -20-30
2011-2012 Results Neurocognitive Testing 90.00 80.00 70.00 60.00 50.00 40.00 Series1 Series2 30.00 20.00 10.00 0.00 Verbal Memory Visual Memory Visual Motor Reaction Time Impulse Control Symptoms
Protecting Future Brains
A Solution?
Education: Recovery Model Concussion Recovery Model vs. Orthopedic Recovery Model Concussions need to be managed differently than orthopedic injuries. No pain. No gain. Does not apply.
When in Doubt, Sit Them Out! No athlete with a concussion should continue to play or return to a game after sustaining a concussion.
Summary Concussions are a significant concern in sport Modern technology is allowing us to manage concussions better than ever We can all contribute to promoting good education and safeplay
Thank-You for Coming! Dr. Martin Mrazik 6-135 Education North Department of Educational Psychology University of Alberta Phone: 780-492-8052 E-mail: mrazik@ualberta.ca