Three paralysed patients have been able to walk again, thanks to precise electrical stimulation of their
spinal cords via a wireless implant, Swiss scientists said.
According to the study published in the journals Nature and Nature Neuroscience, after a few months of training the
patients with chronic paraplegia were able to control previously paralysed leg muscles even in the absence of electrical
The study, called STIMO (STImulation Movement Overground), establishes a new therapeutic framework to improve
recovery from spinal cord injury, said researchers from the Ecole Polytechnique Federale de Lausanne (EPFL) and the
Lausanne University Hospital (CHUV) in Switzerland.
All patients involved in the study recovered voluntary control of leg muscles that had been paralysed for many years, they
Unlike the findings of two independent studies published recently in the US on a similar concept, neurological function was
shown to persist beyond training sessions even when the electrical stimulation was turned off.
"Our findings are based on a deep understanding of the underlying mechanisms which we gained through years of
research on animal models. We were thus able to mimic in real time how the brain naturally activates the spinal cord," said
EPFL neuroscientist Gregoire Courtine.
"All the patients could walk using body weight support within one week. I knew immediately that we were on the right
path," said CHUV neurosurgeon Jocelyne Bloch, who surgically placed the implants in the patients.
"The exact timing and location of the electrical stimulation are crucial to a patient's ability to produce an intended
movement. It is also this spatiotemporal coincidence that triggers the growth of new nerve connections," said Courtine.
This study achieves an unprecedented level of precision in electrically stimulating spinal cords, researchers said.
"The targeted stimulation must be as precise as a Swiss watch. In our method, we implant an array of electrodes over the
spinal cord which allows us to target individual muscle groups in the legs," said Bloch.