Dr. Geoffrey Manley, a neurosurgeon at the University of California, San Francisco, wants the medical establishment to change the way it deals with brain injuries. His work is motivated in part by what happened to a police officer he treated in 2002, just after completing his medical training.

The man arrived at the emergency room unconscious, in a coma. He had been in a terrible car crash while pursuing a criminal.

Two days later, Dr. Manley’s mentor said it was time to tell the man’s family there was no hope. His life support should be withdrawn. He should be allowed to die.

Dr. Manley resisted. The patient’s brain oxygen levels were encouraging. Seven days later the policeman was still in a coma. Dr. Manley’s mentor again pressed him to talk to the man’s family about withdrawing life support. Again, Dr. Manley resisted.

Ten days after the accident, the policeman began to come out of his coma. Three years later he was back at work and was named San Francisco Police Officer of the Month. In 2010, he was Police Officer of the Year

“That case, and another like it,” Dr. Manley said, “changed my practice.”

But little has changed in the world of traumatic brain injuries since Dr. Manley’s patient woke up. Assessments of who will recover and how severely patients are injured are pretty much the same, which results in patients being told they “just” have a concussion, who then have trouble getting care for recurring symptoms like memory lapses or headaches. And it results in some patients in the position of that policemen, who have their life support withdrawn when they might have recovered.