Radical spinal implant helps paralysed patients walk again
Electrodes were implanted in five patients and all regained some movement
■
Asmall group of paraplegic patients have once again been able to take steps after researchers implanted a device to electrically stimulate their spinal cords.
Two separate teams of scientists have revealed for the first time that the technique, together with physical training, has allowed three out of the five individuals treated to walk again after losing all voluntary movement below the site of the injury.
“It is incredible to be able to be in there and actually see them taking their first steps,” said Dr Claudia Angeli of Kentucky Spinal Cord Injury Research Centre at the University of Louisville, and a co-author of one of the studies. “It is an emotional time for the individual [themselves] because it is something that they have been told they are never going to be able to do again.”
In a study published in the New England Journal of Medicine, Angeli and colleagues report that they implanted an array of 16 electrodes in the lower back of four patients, paralysed after mountain bike or traffic accidents several years before. The device, originally developed many years ago for pain control, was placed below the site of injury, covering regions that send sensorimotor signals to the legs while a battery was implanted in the abdominal wall, allowing the frequency of the stimulation, its intensity and duration, to be ■ tweaked wirelessly. Electrical activity produced by muscles in the legs was monitored during the sessions.
“We know the spinal cord has the ability to organise very detailed motor activity,” said Angeli. “But before the injury it was getting commands from the brain and it was getting information from the environment as well.”
Angeli said that it is thought that when the implanted device is turned on, the resulting electrical stimulation raises the excitability of the spinal cord — in a sense making it more alert. “It is like it is more aware, it actually can listen to that little whisper from the brain that is still there and it can generate the motor pattern,” said Angeli.
All four of the individuals had lost all motor control below the site of the injury, although two had some level of sensation.
After implantation of the device and locomotor training, the latter two were eventually able to walk over ground unassisted. One was able to walk after 81 sessions of stimulation over 15 weeks, while the other was able to walk after 278 sessions.
The other two individuals became able to stand and sit independently and one was also able to make some stepping motions on a treadmill when supported.