Last year two paralyzed people briefly stood again, aided by a device that electrically stimulates the lower spinal cord. They were among the first beneficiaries of a hugely promising technique that researchers hope could one day enable many paralyzed people to walk again.
The spinal cord carries the brain signals that control movement of the limbs. If the cord gets clipped by disease or injury, the communication lines go dead; because nerve fibers have limited ability to regrow, the resulting paralysis can be permanent. But starting in the 1990s, UCLA neuroscientist Reggie Edgerton showed that when stimulated with small electrical pulses, the spinal cord can wake up those nerve fibers and coordinate standing and walking—without any input from the brain. Edgerton implanted electrodes in paralyzed rats, then stimulated their spinal cords while researchers moved the animals’ legs in a stepping motion on a treadmill. After four to eight weeks of ...
