1. Vanderbilt Sports Concussion Center, Vanderbilt University Medical Center, Nashville, TN, USA
2. Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
3. Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA
4. Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center, University of North Carolina, Chapel Hill, NC, USA
5. Injury Prevention Research Center, University of North Carolina, Chapel Hill, NC, USA
6. Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
7. Department of Neurological Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
8. Health and Safety Department, National Football League, New York, NY, USA