Advance made in paralysis recovery
Researchers excited by electrical implant tests
WASHINGTON — Three people whose legs were paralyzed for years can stand and take steps again thanks to an electrical implant that zaps the injured spinal cord, researchers reported Monday.
The milestone, reported by two teams of scientists working separately, isn’t a cure. The patients walk only with assistance, holding on to a rolling walker or with other help to keep their balance. Switch off the spinal stimulator and they no longer can voluntarily move their legs.
But during one physical therapy session at the Mayo Clinic, 29-yearold Jered Chinnock moved back and forth enough to cover about the length of a football field.
“I’m really excited about this,” said Johns Hopkins University rehabilitation expert Dr. Cristina Sadowsky, who wasn’t involved in the new research. It tapped into “residual connections that are not being used” after a spinal cord injury.
Still, “not everybody who has a similar injury will respond the same,” cautioned Sadowsky, who directs spinal cord therapy at Baltimore’s Kennedy Krieger Institute.
Severe spinal cord injuries leave the brain’s “get moving” instructions unable to reach the nerves that activate muscles. Researchers have tried other technologies, such as encasing patients in robotic-like exoskeletons or implanting muscle stimulators, to help move paralyzed limbs.
With the new approach, the three patients are taking steps under their own power, intentionally moving, according to the reports published Monday by Nature Medicine and the New England Journal of Medicine.
How does it work? One theory: Circuits of nerves below the injury site are dormant, but still living. Applying electrical current, in customized patterns, could wake up some of those circuits and, with rigorous rehab to revive the rusty connections, eventually enable them to receive simple commands.
“Recovery can happen if you have the right circumstances,” said University of Louisville professor Susan Harkema, who co-authored the New England Journal study. The spinal cord “relearns to do things, not as well as it did before, but it can function.”