Why does a spinal cord injury stop you walking?
The spinal cord is the cable linking the brain to the muscles. When it is damaged, the "walk" message leaving the brain no longer reaches the part of the cord that drives the legs. The person is paralysed even though their legs and brain work. The problem is lost communication more than damaged legs.
Electrical stimulation of the cord can wake that region up, but it is often triggered by pre-set programmes, which force people to adapt their movements to the device.
What did the researchers do?
The team built a "brain-spine interface": a digital bridge between the brain and the spinal cord. Two implants placed on the motor cortex record brain activity (each has 64 electrodes). A computer decodes what the person wants to do with their legs and adjusts, live, the electrical stimulation applied to the spinal cord at the regions that drive walking. In plain terms, the intention to move is picked up by the implants and turned into stimulation of the spinal cord in real time and wirelessly.
The clinical trial enrolled a 38-year-old man with an incomplete injury of the neck part of the spinal cord, sustained in an accident ten years earlier. The whole system is fully implanted.
What did the bridge make possible?
The interface is calibrated within a few minutes and its reliability stayed stable for a year, including during independent use at home. The participant reports natural control over his legs: he can stand, walk, climb stairs and cross complex terrain.
Rehabilitation supported by the interface also improved his neurological recovery. He regained the ability to walk with crutches on the ground even when the interface is switched off.
Key figures
- 1 yearof stable reliability of the brain-spine bridge, including independent use at home
- a few minutesto calibrate the interface
- 1 patienta 38-year-old man, with a neck-level spinal cord injury sustained ten years earlier
What does this change for patients?
If the approach is confirmed, it could one day give people paralysed by a spinal cord injury more natural control of movement. The authors describe a framework for restoring control of movement after paralysis.
For now it is a research result obtained in one patient. It is not an available treatment.
What are the limits?
The validation was limited to one person, with a severe but partial spinal cord injury. It is not yet known whether the approach will work for other injury locations or severities. The participant had also already used spinal cord stimulation in an earlier trial, which may have made set-up easier.
The device requires major surgery (implants in the skull and on the spinal cord). The researchers stress that other studies will have to confirm these results in more people.
Living with paralysis: Mima beside you
This digital bridge was tested in one man, as research. It opens a path to restoring movement, but it is not available to patients.
Mima does not treat; she keeps you company. You can tell her about your rehabilitation, pain and tiredness, and she keeps a clear picture over the days for your team. A question to ask: "Which trials or rehabilitation programmes might be relevant to me?"
Frequently asked questions
What is a brain-spine interface?
It is a system that reads brain activity with implants and passes it, through a digital bridge, to electrical stimulation of the spinal cord, to restore control of the legs.
Does the patient walk normally?
He reports natural control of his legs with the interface on, and he walks with crutches even when it is off. It is not a cure for the injury.
Is this treatment available?
No. The study published in Nature in 2023 describes a clinical trial with a single participant. Studies in more people are needed.
Why does AI come into this?
The system has to decode brain signals in real time to know which movement the person wants to make. That translation relies on decoding models learned during calibration.
The original study
Lorach H, Galvez A, Spagnolo V, et al. “Walking naturally after spinal cord injury using a brain-spine interface.” Nature, 24 May 2023. DOI : 10.1038/s41586-023-06094-5
Read the full study in NatureThis article summarises a scientific study and is not medical advice.