A 16-electrode array implanted into the lower region of his spinal cord, which stimulated spinal nerves with continuous electrical activity and training helped to restore function.
The results are potentially revolutionary, as they indicate that the spinal cord is able to recover its function years after becoming damaged.
Previous studies in animals with lower limb paralysis have shown that continuous electrical stimulation of the spinal cord below the area of damage allows an animal to stand and perform locomotion-like movements. That's because the stimulation allows information about proprioception – the perception of body position and muscle effort – to be received from the lower limbs by the spinal cord. The spinal cord, in turn, allows lower limb muscles to react and support the body without any information being received from the brain
Lancet (2011) - Effect of epidural stimulation of the lumbosacral spinal cord on voluntary movement, standing, and assisted stepping after motor complete paraplegia: a case study
First, the man had extensive training in which his legs were moved by physiotherapists while his weight was supported by a harness. During this time no improvement was observed.
He then had a 16-electrode array implanted into the lower region of his spinal cord, which stimulated spinal nerves with continuous electrical activity. When the implant was switched on and he was helped into the correct position, he succeeded in holding his own body weight and standing on his first attempt.
Then something unexpected happened. Seven months into training on how to stand using the implant, he tried to move his toe while the stimulation was on. "He just started trying to move his toe," says Angeli. "He was like, 'look it's wiggling!' Further testing showed that he was able to move his leg and ankle, too – indicating that voluntary signals from the brain were crossing the lesion.
Over time, the volunteer also gained increased bladder control and sexual function, and had better temperature regulation. All of these abilities involve input from the brain, confirming information could now be sent across the damaged area of the spine, as long as the stimulation was on.