ANDREA SEABROOK, host:
Welcome back to All Things Considered from NPR News. I'm Andrea Seabrook. Dave Savage has been living with just one hand for 35 years because of a workplace accident. Now, thanks to a hand transplant, he's teaching scientists new things about the human brain. See, this Michigan man can feel things with his new hand because his brain seems to be rewiring itself. NPR's Richard Knox has a story.
RICHARD KNOX: Dave Savage, who's 56, says he wakes up every morning happy to realize that he has two hands again.
Mr. DAVID SAVAGE: It's like you're waking up from a bad dream. You've had this dream all night long, you know, like you are falling or whatever. And you wake up, and you're just laying in bed. It's that kind of feeling.
KNOX: He was 19 when his right hand was mangled in a metal-stamping machine. He's lived most of his life with a hook in place of a hand. Then, almost two years ago, he became the third American to get a hand transplant from a cadaver donor. His new hand is still gaining strength, but he puts it to good use.
Mr. SAVAGE: I can swing a hammer. I can throw a football. I can throw a baseball. I couldn't do that with a hook. The everyday things in life, turn doorknobs, you know, turn on light switches.
KNOX: When a limb is amputated, the parts of the brain that control it and register feeling, hot and cold, pressure and pain, go blank. It's almost like deleting a computer program. Gradually, the brain uses that empty real estate for other things. Experts have long assumed that this brain reorganization is irreversible, especially years after an amputation. But Savage is proving them wrong. Neuroscientist Scott Frey of the University of Oregon is studying Savage's brain. He says it's remodeling itself again.
Dr. SCOTT FREY (Department of Psychology, University of Oregon): What was remarkable is really that, after 35 years of complete deprivation, this sensory map of the hand could be that reversible in a mere four months after a hand transplant.
KNOX: The findings are in the journal Current Biology. Frey thinks, whatever brain functions took over that blank area have gone back to where they belong. Now, Savage is only one patient, but researchers think the fact that his middle-aged brain could rewire itself this way has big implications, for instance, for the design of better artificial limbs.
Dr. FREY: We're entering a really exciting era right now, where the ability to marry technology to the human brain is becoming a very real thing.
KNOX: Frey thinks the brain's newfound flexibility might lead to prostheses that function more naturally and maybe even have a sense of touch. Dr. Warren Breidenbach is the surgeon at Jewish Hospital in Louisville who did Savage's hand transplant. He sees other implications.
Dr. WARREN BREIDENBACH (Surgeon, Jewish Hospital, Louisville): It means that a stroke victim who has lost the ability to function could possibly recapture it as long as the brain was not scarred or actually dead tissue.
KNOX: Maybe even years after a stroke. Hand transplant patients get intense and long lasting physical therapy. That may be one reason their brains recover so well. Breidenbach also thinks the brain's ability to adapt might one day open the door for people born without a hand.
Dr. BREIDENBACH: So, here's the question. If someone is born without a hand, and I put a new hand on, will they be able to feel? The first step of answering that question would be doing patients like Mr. Savage.
KNOX: Researchers may soon have more patients like Dave Savage to study. 44 hands have been transplanted around the world so far, almost all with good success. Breidenbach says some U.S. centers are gearing up to do more. One reason may be the growing number of military amputees. It's no accident that much of this research is funded by the Department of Defense. Richard Knox, NPR News.