Researchers at Georgia Tech realized that because people with concussions walk funny, they can detect concussees by imaging and analyzing their walks. Check out the Youtube video of the concussion detection system demo.
Meanwhile, a recent article in MIT Technology Review describes technology for Sensing Brain Pressure without Surgery. People with concussions or serious hemorrhages need to be monitored for pressure on the brain (which could further damage brain tissue). Right now, the monitoring technique involves drilling a hole in the skull and inserting a catheter. MIT researchers are developing ultrasound as a new non-invasive technique for this role.