In a move that gives cautious hope to the millions of people suffering some form of paralysis, a team of researchers from UCLA, Caltech and the University of Louisville has given a man rendered paralyzed from the chest down after a hit-and-run accident in 2006 the ability to stand and take his first tentative steps in four years.
The team used a stimulating electrode array implanted into the man’s body to provide continual direct electrical stimulation to the lower part of the spinal cord that controls movement of the hips, knees, ankles and toes, to mimic the signals the brain usually sends to initiate movement.
Instead of bypassing the nervous system to directly stimulate the leg muscles, the electrical signals provided by the array stimulate the spinal cord’s own neural network so it can use the sensory input derived from the legs to direct muscle and joint movements. The stimulation therefore doesn’t induce movement, but taps into a network of spinal cord nerves that are capable of initiating movement on their own without the help of the brain, which then work together with cues from the legs to direct muscle movement.
The research team’s work builds on previous research at UCLA that showed animals with spinal-cord injuries could stand, balance, bear weight and take coordinated steps while the outermost part of the spinal canal – or epidural space – is stimulated.
Thanks to the breakthrough the test subject, 25 year old Rob Summers, is able to supply the muscular push required to stand up and remain standing for up to four minutes at a time. With periodic assistance, Summers is able to stand for up to an hour, and with the aid of a harness support and some assistance from a therapist he is able to take steps on a treadmill.
