A team of Swiss researchers have successfully helped three paraplegic patients walk again.

Called STIMO (STImulation Movement Overground), the framework utilizes physical therapy and a wireless implant that sends precisely timed electrical signals along the spinal cord. STIMO has proven to be effective and precise enough that patients can move joints without the aid of the electrical pulses.

"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 neuroscientist Grégoire Courtine of the Swiss Federal Institute of Technology in Lausanne, Switzerland (EPFL) in a statement released by the institute.

A stimulated walk

The STIMO study used these electrical pulses in a targeted way. A collection of electrodes were placed along the patients' spinal cords in a way that allowed the scientists to target individual groups of muscles in the legs. The pulses mimicked the signals the brain would send to produce walking movements.

For their part, the patients had to line up their brain's intention to walk with the pulses. The theory was that synchronized pulses from the implant with the steps might get the nervous system — previously inert and leaving the patients unable to walk — working again.

It didn't take long for the patients and the scientists to start seeing results.

"All three study participants were able to walk with body-weight support after only one week of calibration, and voluntary muscle control improved tremendously within five months of training," Courtine said in the statement. "The human nervous system responded even more profoundly to the treatment than we expected."

Patients engaged in long sessions of rehabilitation, often walking more than 1 kilometer (0.6 miles) with the aid of the implant. According to the institute's statement, "these longer, high-intensity training sessions proved crucial for triggering activity-dependent plasticity — the nervous system's intrinsic ability to reorganize nerve fibers — which leads to improved motor function even when the electrical stimulation is turned off."

You can learn more about the research in the video below.

According to a report from The Verge, one of the study's participants, David Mzee, was able to move a toe in his paralyzed left leg sometime last year. Another participant, Gert-Jan Oskam, is able to walk along the ground with crutches. The third, Sebastian Tobler, can use a walker to move now.

Stepping is still a challenge, however. All three men still mainly use wheelchairs to get around, but Mzee and Oskam can take a few steps on their own using crutches, even without the use of the implant's pulses.

Courtine and his team published their findings in the journal Nature. A complementary study was published in Nature Neuroscience.

Next steps

There's still a lot of work to be done until implants like these are available to a wider audience. To that end, Courtine and Lausanne University Hospital neurosurgeon Jocelyne Bloch, who was also involved in the study, have co-founded GTX medical. The organization will use the findings from the studies and attempt to turn the STIMO process into one that can be used at hospitals and clinics.

"We are building next-generation neurotechnology that will also be tested very early post-injury, when the potential for recovery is high and the neuromuscular system has not yet undergone the atrophy that follows chronic paralysis. Our goal is to develop a widely accessible treatment," Courtine said.

3 paralyzed men are learning to walk again
STIMO (STImulation Movement Overground) involves physical therapy and targeted electrical stimulation to help the brain regain control over paralyzed muscles.