 And if you see a child alone in a car in the heat, call 911 to get them out. Greg Johnson, UND hockey's all-time leading scorer, has been posthumously diagnosed with CTE. That's according to his family and the Concussion Legacy Foundation. CTE, or chronic traumatic encephalopathy, is a degenerative brain disease that affects people with repeated concussions and head trauma. Johnson died by suicide five years ago this week.