Until recently, there had been little evidence-based research on how to rebuild marriages after such a tragedy. Indeed, doctors frequently warn uninjured spouses that the marriage may well be over, that the personality changes that can result from brain injury may do irreparable harm to the relationship.

Captain Kelly and Ms. Giffords largely have kept private their own experiences in this regard, and they declined to be interviewed for this article. Still, therapists are beginning to understand the obstacles that couples like them face, and what they are learning may lead to new counseling techniques to help restore the social links that give lives meaning.

Contrary to conventional wisdom, many relationships do survive after a spouse suffers a brain injury. Some studies find divorce rates well below the national average among these couples. A 2007 investigation found that the divorce rate was around 17 percent in couples followed for as long as 90 months after a spouse sustained a brain injury.

That is not to say these couples are always happy.

“Two or three years later, they want a whole lot more than simply to be alive,” said an author of the 2007 study, Jeffrey S. Kreutzer, a psychologist at Virginia Commonwealth University in Richmond. “While people may technically be married, the quality of their relationship has been seriously diminished.”

Dr. Kreutzer and other psychologists at V.C.U. are among the few therapists in the country trying to develop marriage counseling techniques tailored to couples dealing with brain injuries. Traditional marriage counselors often hope to restore people and their relationships to their original luster. For Dr. Kreutzer and his team, recovery often means teaching uninjured spouses to forge a relationship with a profoundly changed person — and helping injured spouses to accept that they are changed people.