This device blocks the spinal cord so that paralyzed people can use their hands again

Melanie Reid was 52 years old when she jumped on a horse, fell and broke her neck. As a result of the injury, her body was paralyzed below the chest. Fourteen years later, after intensive physical therapy, she gradually regained some function of her right hand, which is a “lifeline,” she said at a news conference. But her left hand remained “useless.”

As a journalist, the injury was devastating because she couldn’t write. Even seemingly simple everyday activities – tying her hair in a ponytail, using an ATM card, even unwrapping candy – were a challenge for her.

Thanks to the new device, he is able to do all this after just two months of use. A device called ARC-EX therapy destroys residual nerve connections at the site of spinal cord injury. Combined with physical rehabilitation, the treatment restored some functionality in the left hand – even after the stimulation was turned off.

Reid was part of a clinical trial with 60 participants that aimed to use spinal cord stimulation to regain control of both hands. Similar treatments have shown promise in paraplegic patients, restoring the ability to walk in just one day. However, they required surgery to place electrodes on the spinal cord.

However, ARC-EX therapy involves delivering two different types of electrical impulses through the skin – no surgery is required. Developed by Grégoire Courtine and colleagues at the Swiss Federal Institute of Technology, the device improved hand strength, pinching and other movements in 72 percent of participants.

Because the device is non-invasive, it is a simple addition to physical rehabilitation programs – sort of like finger pilates, the team explained. The study only included two months of stimulation, and extending the time could potentially improve results even further.

Stimulation only helps with finger and hand dexterity, not walking. But for Reid, that’s what matters. “Everyone thinks that after a spinal injury, all you want is to be able to walk again,” she said. But “the most important thing is that hands work… (and) the profits can be life-changing.”

Broken bridges

All study participants had a spinal cord fracture, approximately at the level of the neck.

With torn nerves, the brain can no longer command the body. Just like a broken telephone line, when you think “move your hand”, the signal will be lost at the moment of interruption. Scientists have long tried to fill this communication “gap” using electrodes that control muscle movement, essentially replacing damaged biological wires with artificial ones.

Spinal cord stimulation is one solution. In 2018, a man walked across a football field, years after he was left paralyzed by spinal cord injuries. With just one day of stimulation, people with complete paralysis can walk around the busy city center and kayak.

The key to recovery, the team explained, is to focus on living nerves. In most cases, even in patients who are considered to have had a “complete” spinal cord injury, there are still nerves remaining, and stimulating them can trigger regrowth and connections.

Imagine your spinal cord as a tree with branches reaching down to your skin. Now imagine that the “trunk” has been partially cut off. By pressing on the skin around the site of injury, it is possible to send electrical signals to the damaged spinal cord “trunk” and allow living neurons near the site of injury to rebuild neural connections.

“In preclinical models, we immediately improved movement after stimulation,” Courtine said. But “more importantly,” we observed the growth of new neurons, as if the body was repairing a damaged nervous system, he added. With sufficient healing, patients could potentially be able to use their hands even without stimulation.

Based on these ideas, the team built the ARC-EX device.

Lawsuit

The clinical trial involved 60 people with spinal cord damage at the neck level. All participants underwent two months of physiotherapy, followed by another two months of physiotherapy combined with ARC-EX stimulation. The group was on average about 46 years old.

As part of physical rehabilitation, each person practiced movements such as pinching, gripping, or moving their entire arm for an hour a day, up to five times a week. Although therapy improved arm and hand function, progress stopped in most patients.

The team then added ARC-EX stimulation with electrodes placed above and below the site of injury. During the therapy, the team controlled the frequency and strength of the blows, which made it easier to move the arms and hands without causing unwanted muscle “vibrations”.

The study was open-label, meaning both participants and researchers knew they were receiving stimulation. This can be a risky endeavor because of the placebo effect — when participants recover because they think they are receiving actual treatment rather than, say, sham stimulation. However, in the case of ARC-EX it is impossible to “blind” the stimulation. Immediately turning on the device causes strange sensations in participants, with the electrical impulses resembling “kind of like a humming noise,” Reid said. Turning off the device also immediately alerted participants. In one example, Reid said she “held the jar with the weights on and with the stimulation on,” but with the stimulation off – unbeknownst to her – she immediately dropped the jar.

In just eight weeks, 72 percent of participants met or exceeded goals for hand strength and dexterity – the ability to grip a cup or pinch with tweezers – as assessed by a battery of tests. Only one person experienced unintended consequences – uncontrolled muscle contractions. However, because stimulation was turned off when they occurred, the team says it is likely unrelated to ARC-EX.

The therapy not only improved hand function. Paralyzed participants also experienced less pain, had fewer breathing problems and slept better.

Enhanced therapy

Stimulation will not work for about 10 percent of people with spinal cord injuries, which have completely severed all nerve connections. But for those who still have residual nerve endings, it makes it easier to restore finger movement.

Sherown Campbell, another study participant, found ARC-EX life-changing. A self-proclaimed “tech geek”, he works constantly on his computer. “The biggest thing I was hoping to improve was focusing on hand function,” he said.

With ARC-EX therapy, his typing speed increased from 25 words per minute to 33 words per minute, “an increase of about 30 percent, which is really significant to me,” he said. But more importantly, his quality of life improved. He can cook and write again – two seemingly simple, everyday activities that give him joy but were robbed by the accident.

Thanks to the success of this trial, the device may soon hit the market. Because it is non-invasive, it can be easily integrated into existing physical therapy sessions. The team is already seeking approval in the United States, and talks with the European Union will soon take place. Pricing is unknown at this time, although Courtine says the goal is to make it widely available.

For Reid, being able to use her left hand is a huge change in her life. It’s “extraordinary,” she said. “It makes you lift your head and look at the world differently.”

Image source: ONWARD Medical NV