US student suffered 'extensive' brain damage in N. Korea

Doctors treating Otto Warmbier, the US student released by North Korea in a coma this week, said Thursday the 22-year-old had suffered severe brain damage, as his father lashed out at the reclusive regime.Warmbier experienced extensive tissue loss in all regions of the brain, doctors said, but he showed no signs of physical trauma and medical tests offered no conclusive evidence as to the cause of his neurological injuries.