A man who became paralysed after a diving accident six years ago regained the ability to move and feel pressure in his hands thanks to brain stimulation. Now, researchers have revealed he maintained this ability for months after the stimulation was turned off. This suggests the intervention has caused a rerouting of his neuronal connections through neuroplasticity.
āWe turned everything off completely, for many months, and yet heās maintained these gains,ā says at Feinstein Institutes for Medical Research in New York. āThatās unheard of.ā
Keith Thomas, 48, was paralysed from the chest down in July 2020. He had no sensation or control over his limbs and had significant muscle wasting, says Bouton.
Advertisement
In 2023, Bouton and his colleagues performed a double neural bypass surgery on Thomas, placing five electrodes into his brain in regions associated with arm movements and feeling. They then connected computer cables to these electrodes, so artificial intelligence could interpret his movement intentions. That information was then wired into electronic splints that stimulated his arms, hands and fingers to carry out his intended movements, enabling him to pick up coffee cups and scratch his face.
To recreate the sense of feeling, the team embedded force sensors into 3D printed wearable devices for Thomasā hands and fingers, which sent feedback via electrical stimulations into the brainās sensory areas.
After conducting a series of experiments ā which even involved ā Bouton says the team planned to stop the stimulation for about a month, to test for any lingering effects. āThen we had a fire in the building, and it actually forced us to stop stimulation for even longer than weād planned, for about three months.ā
The unexpected interruption led to surprising findings: Thomas continued to maintain strength, feeling and function in his hands. āHeās now also controlling individual fingers with even more accuracy, so thatās big,ā says Bouton.
In a video interview with Ā鶹“«Ć½, Thomas raised his elbows nearly to shoulder level and described feeling ātinglingā in his wrist in response to pressure, even when heās āunplugged from the computerā. āWhen I first felt it, it was amazing,ā he says. āIām used to it now.ā
Ā at the University of California, Davis, says the work suggests that this approach promotes lasting recovery of the nervous system. āThe goal is to help the nervous system partially heal so the person can move their own body better,ā he says.
āIf these improvements persist even when the system is turned off, then the device is doing more than temporarily restoring function,ā says at UCLA. āIt may be helping the nervous system reorganise itself through neuroplasticity.ā
This describes the brainās ability to rewire itself by forming new neural connections, such as or even . āAfter an injury such as spinal cord injury, those same mechanisms may help restore function by strengthening spared pathways or recruiting alternative circuits, allowing neural signals to travel through networks that were previously too weak to support meaningful movement,ā says Lu.
The researchers have observed stronger neural responses in Thomasā sensory cortex since the intervention.
But this is just a single case report, so itās unclear how well this approach would work on other people with paralysis from different types of injuries. at the University of Chicago, says he has spent years working on stimulation and continues to find that some respond better than others, and some not at all. āAnd we have no idea why,ā he says. āSo, the question is: can you replicate it? This is a really ambitious study, but we need to see them replicating their results in more participants before we believe the hype.ā
As to Thomasā future, āat this point now we know nothingās impossible, or anythingās possibleā, says Boulton. āI think itās possible he will continue to to improve,ā he adds.
Nature Medicine
