Timing of concussion diagnosis is related to head impact exposure prior to injury.

@article{Beckwith2013TimingOC,
  title={Timing of concussion diagnosis is related to head impact exposure prior to injury.},
  author={Jonathan Beckwith and Richard M. Greenwald and Jeffrey J. Chu and Joseph J. Crisco and Steven Rowson and Stefan M. Duma and Steven P. Broglio and Thomas W. McAllister and Kevin M. Guskiewicz and Jason P. Mihalik and Scott A. Anderson and Brock E. Schnebel and Per Gunnar Brolinson and Michael W. Collins},
  journal={Medicine and science in sports and exercise},
  year={2013},
  volume={45 4},
  pages={
          747-54
        }
}
PURPOSE Concussions are commonly undiagnosed in an athletic environment because the postinjury signs and symptoms may be mild, masked by the subject, or unrecognized. This study compares measures of head impact frequency, location, and kinematic response before cases of immediate and delayed concussion diagnosis. METHODS Football players from eight collegiate and six high school teams wore instrumented helmets during play (n = 1208), of which 95 were diagnosed with concussion (105 total cases… 

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