Hand transplant recovery sheds new light on touch – Quincy Herald-Whig | Illinois & Missouri News, Sports

By LAURAN NEERGAARD AP Medical Writer

WASHINGTON (AP) - Recovery of feeling can gradually improve for years after a hand transplant, suggests a small study that points to changes in the brain, not just the new hand, as a reason.

Research presented Sunday at a meeting of the Society for Neuroscience sheds light on how the brain processes the sense of touch, and adapts when it goes awry. The work could offer clues to rehabilitation after stroke, brain injury, maybe one day even spinal cord injury.

"It holds open the hope that we may be able to facilitate that recovery process," said Dr. Scott Frey, a cognitive neuroscientist at the University of Missouri in Columbia.

When surgeons attach a new hand, nerves from the stump must regenerate into the transplanted limb to begin restoring different sensations, hot or cold, soft or hard, pressure or pain. While patients can move a new hand fairly soon, how quickly they regain feeling and what sensations they experience vary widely.

After all, the sense of touch isn't just about stimulating nerves in the skin. Those nerves fire signals to a specific brain region to decipher what you're touching and how to react. Lose a limb and the brain quickly rewires, giving those neurons new jobs. Frey's work shows the area that once operated a right hand can start giving the left hand a boost.

Brain scans suggest those changes are at least partially reversible if someone gets a hand transplant years later. But little is known about how the brain's reorganization affects recovery.

Telling where on the palms or fingers they're being touched without looking is a persistent problem for hand transplant recipients, and a function of the brain's main sensory area. Frey's team compared four transplant recipients, four patients whose own hands were reattached immediately after injury, and 14 uninjured people.

The longer the time since their surgeries, the more accurately patients located a light touch, Frey reported. Two who've had transplanted hands for eight and 10 years, respectively, were almost as accurate as uninjured people. So were two patients whose own hands were reattached 1 and three years earlier.

Nerve regeneration is thought to take about two years, Frey said.

More here:
Hand transplant recovery sheds new light on touch - Quincy Herald-Whig | Illinois & Missouri News, Sports