The impact of head impacts in sports Jason P. Mihalik, PhD, CAT(C), - PowerPoint PPT Presentation

The impact of head impacts in sports Jason P. Mihalik, PhD, CAT(C), ATC Associate Professor, Department of Exercise and Sport Science Co-Director, Matthew Gfeller Sport-Related TBI Research Center @jmihalik79

Disclosures Chief Science Officer

“ I was wearing a helmet designed to prevent concussions, so I can’t have a concussion ”

Helmet testing in 1912

Concussion: A multifaceted condition Mechanism of Physical exam injury Postural stability Symptomatology Knowledge, Concussion Attitudes, history Behaviors Traumatic Brain Cognition Treatment Injury

Head Impact Monitoring Systems

Impact Data

Neurosurgery, 2007

Mechanism of injury

Player Rotational ΔSymptom ΔSOT ΔANAM Linear Impact Case # Position* acceleration Magnitude (g) Location Scores† Composite‡ Composite‡ (rad/s 2 ) 1 OL 60.31 5419.18 Front 2 -4.88 N/A 2 RB 60.51 163.35 Top 12 -19.15 -0.20 3 LB 63.84 5923.27 Front 8 -15.68 -0.35 4 WR 66.36 5573.42 Front 23 3.85 N/A RB 5 77.68 3637.48 Top 8 -29.18 0.22 6 DB 84.07 5299.57 Front 7 -2.25 -0.26 7 DB 85.10 3274.05 Top 4 4.11 0.49 8 LB 94.20 7665.10 Front No baseline data available 9 DL 99.74 8994.40 Front 27 -4.07 0.14 10 OL 100.36 1085.26 Top 0 -2.00 1.01 11 § 3 LB 102.39 6837.62 Right 30 -60.01 -1.56 12 OL 107.07 2811.45 Top 9 -20.57 -0.76 13 § 5 RB 108.02 6711.00 Front 2 -17.79 N/A 14 DB 109.88 6632.77 Top 16 2.70 -0.06 15 § 14 DB 115.50 2303.63 Top 2 -1.49 N/A 16 DL 119.23 7974.22 Right 12 2.89 0.12 17 LB 157.50 1020.00 Front 14 0.71 0.42 18 WR 168.71 15397.07 Back 13 7.33 0.79 19 RB 173.22 4762.74 Top 32 8.08 N/A

Special teams & closing distance • 3x risk of severe impacts during special teams plays vs. offense/defense • Over 4.5x risk of severe impacts during long closing distance (>10yds) vs. short closing distance (<10yds) Ocwieja, Mihalik, ABME 2012

NFL’s 2011 kick-off rule change Table 2. Regular Season Game Kickoff Statistics in 2011; 3-year Comparison Result of Kickoff Total Fair Kick Out of Short Free or Opponent Total Year Touchbacks Returns Catches Bounds Onside Kicks Received Kickoffs 2008 2114 371 7 36 47 1 2576 2009 2004 401 12 30 36 1 2484 2010 2034 416 7 39 43 0 2539 2011 1375 1120 1 26 50 0 2572 Average 2008-2010 2050.7 396 8.7 35 42 0.7 2533 33% reduction in the number of returned kickoffs

NFL’s 2011 kick-off rule change Table 3. Significant Injuries As a Function of Kickoff Plays 2011 Regular Season; 3-year Comparison Regular Season Games Year Concussions Neck/Spine Fractures ACL Sprain All Injuries 2008 26 12 10 3 152 (N=2576) (1.0%) (0.5%) (0.4%) (0.1%) (5.9%) 2009 25 7 6 2 147 (N=2484) (1.0%) (0.3%) (0.2%) (0.1%) (5.9%) 2010 28 7 11 8 135 (N=2539) (1.1%) (0.3%) (0.4%) (0.3%) (5.3%) 2011 15 8 8 7 136 (N=2572) (0.6%) (0.3%) (0.3%) (0.3%) (5.3%) Average 2008-2010 26.3 8.7 9.0 4.3 144.7 (N=2533) (1.0%) (0.3%) (0.4%) (0.2%) (5.7%) 42% reduction in the number of concussions

High school football rules? Table 1. HS RIO™, Original Sample Competition Football Injuries by Punt, Kickoff and General Play, 2005/06-2011/12 School Years. % of Competition Injuries that General Punt Kickoff were Concussions Play Year 2005/06 23.9% 21.1% 10.8% 2006/07 19.6% 43.0% 11.2% 2007/08 19.0% 31.5% 12.3% 2008/09 18.1% 34.4% 14.0% 2009/10 14.6% 39.8% 18.9% 2010/11 37.0% 61.4% 24.3% 2011/12 35.0% 48.3% 20.8% Overall 24.0% 42.4% 16.0%

Concussion: A multifaceted condition Mechanism Head Impact of Physical exam Indicators injury Postural stability Symptomatology Knowledge, Concussion Attitudes, history Behaviors Traumatic Brain Cognition Treatment Injury

Head impact indicators

Med Sci Sport Exer, 2010

Thresholds & positive predictive values Sensitivity Specificity Positive Predictive Threshold (95% CI) (95% CI) Value 20 g 100% 56% 0.01% 50 g 95.8% 90.4% 0.1% Resultant Linear Head Acceleration 75 g 75.0% 97.0% 0.2% 100 g 45.8% 99.0% 0.4%

What does this mean for the clinician? Threshold Practice Game PV+ (n) 50 g 358 620 0.1% (1 inj) Resultant Linear Head 75 g 73 166 0.2% (<1 inj) Acceleration 100 g 24 79 0.4% (<1 inj) Number of impacts exceeding various thresholds in one complete high school football season: 16,402 total impacts collected (8791 in practice; 7611 in games)

The bottom line • There is NO reliable concussion threshold • We all want to better protect our athletes • Must take many things into account …. 1. Cost 2. Risks 3. Does it add clinical value? • Research will continue to benefit from monitoring technologies

Matthew Gfeller Center

Jason P. Mihalik, PhD, CAT(C), ATC Matthew Gfeller Sport-Related TBI Research Center jmihalik@email.unc.edu 919.962.2573 http://tbicenter.unc.edu @jmihalik79