A study [1] published Wednesday in PLOS ONE found evidence of brain injuries that could lead to cognitive issues in college football player -- even in cases where the football players did not suffer concussions. The study was based on analysis of players on three college football teams. The injuries -- which did not involve concussions -- were identified with blood tests to show the potential for blood-brain barrier disruption. The danger took place in cases of "repeated sub-concussive events."