There’s been a lot of talk and ongoing studies about CTE and what causes the damage. So far the NFL has taken the brunt of the criticism but there’s been speculation about the effects of boxing, MMA and action sports. Now we have the first known case of that same chronic brain damage in action sports. BMX icon Dave Mirra, who died in February, suffered from CTE, a University of Toronto neuropathologist has concluded. Multiple neuropathologists confirmed the diagnosis.