New York ? Nearly 10 years after a brain injury left a firefighter virtually mute, he suddenly started talking to his wife and sons last weekend. A couple of years ago, it happened with a severely injured car accident victim who’d spent 19 years in silence.

And before that, a paralyzed policeman whose brain had been damaged in a shooting suddenly regained his speech after eight years.

Normally, brain-injured patients who get better do so within the first five years, especially in the first two years, and usually the change is gradual.

So what’s the explanation for these reports of long-delayed, sudden improvement?

“We really don’t know for sure what’s going on,” says Anthony Stringer, director of neuropsychology in the department of rehabilitation medicine at the Emory University School of Medicine.

While the answer might involve some long-delayed change in the brain, experts said Tuesday, a sudden improvement might also result from a far different cause, like a change in medications or treatment of some other medical condition that’s been suppressing mental function.

Experts say such cases are so rare they don’t have much to study, and note that news accounts usually leave out the details needed to evaluate possible causes.

Catching up

The latest case involves firefighter Donald Herbert, 43, who has lived at a nursing home in suburban Buffalo for more than seven years.

In December 1995, the roof of a burning home collapsed on him. He went without oxygen for several minutes before he was rescued, and he ended up blind with little, if any, memory. He was largely mute and showed little awareness of his surroundings.

But last Saturday, he suddenly asked for his wife, Linda. And over the next 14 hours, until he fell asleep early Sunday morning, he chatted with her, his four sons and other family and friends, catching up on what he’d missed.

“How long have I been away?” Herbert had asked.

“We told him almost 10 years,” said his uncle, Simon Manka. “He thought it was only three months.”

The nursing home and the family have declined to describe his condition since then or discuss medical details of the case.

Other cases

There have been a few other widely publicized examples of brain-damaged patients showing sudden improvement after a number of years. In 2003, an Arkansas man, severely disabled and largely silent for 19 years after a car accident, stunned his mother by saying “Mom” and then asking for a Pepsi. His brain function remained limited, his family said months later.

And Tennessee police officer Gary Dockery, left paralyzed and mute after a 1988 shooting, began speaking to his family one day in 1996, telling jokes and recounting annual winter camping trips. But after 18 hours, he never repeated the unbridled conversation of that day, though he remained more alert than he had been. He died the following year of a blood clot on his lung.

None of these people were in a “persistent vegetative state” like Terri Schiavo, the Florida woman whose feeding-tube case raised anguished end-of-life ethical discussions.

Recovery possibilities

So what might explain long-delayed, sudden recoveries from brain injury?

One possibility is that the brain may have been impaired not just by the injury, but by some other condition, such as an infection or unrecognized seizure. When that other condition is treated or removed, the person’s mental status improves, even though the effect of the brain injury itself is unchanged.

“Something is holding them down further” than the brain injury itself does, said Dr. Ross Zafonte, chair of the department of physical medicine and rehabilitation at the University of Pittsburgh.

For example, some people have longstanding but subtle seizures after a head injury that can induce confusion, and when they are treated, “Boom, people get better,” Bernat said. “I’ve seen that happen.”

Liver disease, lung problems, anemia, infections and diabetes can also contribute to neurological problems, he said. So can side effects from certain drugs, and so a change in medication might bring about a sharp improvement in mental status, he said.

“I’m not saying that’s the case here (with the firefighter),” he said, “but these are the kinds of details we would need to know in order to properly interpret what happened.”