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There’s new hope that paralyzed people may soon walk again. Researchers from Switzerland were successful in sending electrical signals to the spine of three men who were completely paralyzed after spinal cord injuries. Within days, all three men could move their torso and legs performing activities such as walking, swimming, and cycling.

Normally, the nerves in the spinal cord send a message to the brain that it wants to move. But a spinal cord injury can severely weaken that communication.

This research, recently published in Nature Medicine, used a device filled with electrodes to boost nerve signals involved in moving your torso and legs. The device was personalized and implanted on each person’s spine where the wires would connect to a neurostimulator in the abdomen. The researchers paired the software the device runs on with a tablet that the men can use to choose which activity they want to do in order to stimulate the right nerves, whether it’s standing or walking up the stairs.

“The real surprise to me was how much we sped up this process,” Andreas Rowald, PhD, research group leader in the department of medical informatics, biometry, and epidemiology at Friedrich Alexander University Erlangen-Nürnberg, and lead author of the study, told Verywell. “In my mind, I thought we would get them to move in a few weeks or a few months but I was not anticipating that we would have them walking on the very first day.”

For Rowald, the goal of getting paralyzed people to move again is personal. When he was younger, he sustained an accident during a weightlifting training session where he temporarily lost motor control of his legs and struggled with chronic back pain. His experience and his research in physics soon made him interested in how movement works and what could cause a loss of movement.

“The human nervous system functions on electricity and I became really interested in how information is relayed from point A to point B, but more importantly, how can I intercept this communication?” he said.

There have been many attempts to help paralyzed people walk again. Scientists have tried repairing the spinal injury directly and electrically stimulating the leg muscle, with little success. A study published this month in Advanced Science found that cell therapy using stem cells could be a potential mechanism for regenerating lost nerves in spinal cord injuries. However, these findings are still in their early phases and it may take years before it’s tested on humans.

But stimulating the spinal cord, also known as epidural electrical stimulation, has been extensively studied in animal models with promising results. A 2014 study published in Science Translational Medicine showed rats with complete spinal cord injuries could move freely when given an epidural electrical stimulation. Research in primates with a spinal cord injury implanted with an epidural electrical stimulation device boosted communication between the brain and spine and improved their walking patterns.

In 2018, a study published in Nature showed the first results of electrical stimulation to the spinal cord in humans with spinal cord injury. After several months, patients recovered voluntary control over paralyzed muscles without stimulation. When given stimulation, patients could walk or go cycling.

But Rowald says that while past research has made great strides in restoring movement, getting someone to take steps again took months. The landmark of his recent paper showed that after just one day, patients with complete spinal cord injury were walking again.

The study invited three patients between 29 and 41 who were paralyzed from a thoracic spinal cord injury to undergo an invasive surgery implanting a paddle-shaped device that would electrically stimulate nerves in the spinal cord. Each patient could not move or feel their legs but had at least six centimeters of the spinal cord below the injured site.

The team first used a generic version of the device to confirm it would target the correct spinal cord segment and then tailored the device for each person’s spinal cord. The device was implanted directly onto the spinal cord where it targeted nerves in the dorsal root—an area where nerves travel to communicate with the brain—in the lower back and tailbone.

Eleven days after the surgery, and one day after testing the electrical stimulation, all three participants were able to walk, stand, swim, and move their torsos. Software in the device could communicate with a tablet where it directs the device to stimulate different movements.

Michel Roccati was one of the three patients who received an implant. A motorcycle accident in 2017 severed his spinal cord and eliminated any feeling in his legs. With the implant, Roccati is regaining movement he has not experienced in years. “I stand up, walk where I want to, I can walk the stairs—it’s almost a normal life,” he told the BBC.

Researchers are one step closer to restoring movement in paralyzed patients. While the research is still early, it gives further evidence that therapeutic alternatives can be made to speed up the recovery time for people with motor impairments.

The device is a huge accomplishment in this field of research, but Rowald cautions its far from a cure for paralysis. While the device stimulated the three men to quickly walk again, their movements were clumsy and jerky. They also needed more training to support their body weight. All men could take about 300 steps but needed body support.

Further, there is always a risk with surgery. Implanting the device requires an invasive surgical procedure because it is placed underneath the vertebra on top of the nervous system. For this reason, people with spinal cord injuries are an ideal group because there is less concern that the researchers can cause damage in the area.

But the number of eligible patients narrows because you need at least six centimeters of uninjured spinal cord below the injury. Younger individuals may be a good group to try this technology out because they have a better chance of recovery.

Rowald said finding a less invasive approach to implant the device can reduce the risk of further injury. “The scalability of this technology would [then] increase dramatically,” he added. “We could use it with people of different age groups, different neurological dysfunctions, and different disease profiles.”

Another concern is the high cost of creating the device—limiting who can afford this intervention. But Rowald assured that the computational optimization done in the study could be a useful framework for clinicians or companies who want to invest more research into implant design and, hopefully, scale down the cost when creating their own interventions.

The researchers plan to expand these findings into a larger clinical trial in the United States and Europe. Further research will look into making the device more accessible by connecting the software to smartphones or wearables, such as the Apple Watch, according to STAT.

“I’m very confident that four to six years from now, we can actually have this [device] in clinics across the world,” Rowald said.

Rowald A, Komi S, Demesmaeker R, et al. Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis. Nat Med. 2022;28(2):260-271. doi:10.1038/s41591-021-01663-5

Katsnelson A. Spinal stimulation steps up. Lab Anim. 2018;47:310. doi:10.1038/s41684-018-0181-x

Wertheim L, Edri R, Goldshmit Y, et al. Regenerating the injured spinal cord at the chronic phase by engineered iPSCs-derived 3D neuronal networks. Adv Sci. Published online February 7, 2022. doi:10.1002/advs.202105694

Wenger N, Moraud EM, Raspopovic S, et al. Closed-loop neuromodulation of spinal sensorimotor circuits controls refined locomotion after complete spinal cord injury. Sci Transl Med. 2014 Sep 24;6(255):255ra133. doi:10.1126/scitranslmed.3008325

Capogrosso M, Milekovic T, Borton D, et al. A brain–spine interface alleviating gait deficits after spinal cord injury in primates. Nature. 2016;539(7628):284-288. doi:10.1038/nature20118

Wagner FB, Mignardot JB, Le Goff-Mignardot CG, et al. Targeted neurotechnology restores walking in humans with spinal cord injury. Nature. 2018;563(7729):65-71. doi:10.1038/s41586-018-0649-2

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