Meet the Irish software engineer helping paralyzed people walk again


Cathal Harte of NeuroRestore is developing software with the goal of interpreting the brain’s intentions to help restore motor function.

Researchers in Switzerland are working on groundbreaking trials that could give paralyzed people back the ability to walk by sending electrical impulses to targeted nerves.

NeuroRestore is a center for research, innovation and treatment focused on “electroceuticals” – a type of neurotherapy that uses electrical stimulation to help neurological function. There are various potential applications for this, such as improving motor function in people who have suffered a stroke or who have Parkinson’s disease.

But a key area of ​​research is restoring motor function to people with chronic spinal cord injury. NeuroRestore researchers worked on a clinical feasibility study called Stimo, which showed very positive results in experimental treatments to help people with complete paralysis walk.

One of the people working on this technology is Cathal Harte, an Irish software engineer who joined NeuroRestore in 2020. He leads the center’s clinical software development efforts.

Cathal Harte. Image: NeuroRestore

The NeuroRestore center was created by the Defitech Foundation, the Vaud University Hospital Center, the Faculty of Biology and Medicine of the University of Lausanne and the Federal Polytechnic School of Lausanne (EPFL).

Some of the team behind NeuroRestore made headlines in 2018 after helping David Mzee, a man who lost the use of his legs to a spinal cord injury, to walk again thanks to to continuous electrical stimulation and a pacemaker type implant.

“I was hired to bring the next-gen software, which really opened the door to the possibilities of doing things automatically,” Harte told

Harte and the NeuroRestore team aim for this software to eventually interpret the brain’s motor intentions and translate them into targeted epidural spinal stimulation that can restore movement to people with paralysis.

Develop the software

Harte said the first generation of NeuroRestore software was more simplistic. It allowed users to make “visual judgments” about electrical stimulation using a separate app.

An important part of software development is testing different stimulation parameters on different nerves. The team can look at this electromyography, or EMG, data to see which muscles are activated by stimulating specific nerves.

“Data is a critical part of the mapping process, it’s for the good of the patient right in front of you,” Harte said.

This data is then used to understand exactly how to stimulate the nerves to create a specific movement, such as a walking motion. Thanks to everything built into the latest version of the software, Harte said it’s possible to incorporate machine learning.

“We know exactly what configuration we’re sending, we know exactly how long we’re pacing,” he explained. “We can annotate all the muscle signals with this information, send it all to a machine learning program, and then it can make the calls.”

Harte explained that machine learning is an important step in bringing this kind of technology to the product stage.

“When you’re a dedicated research team, you have a patient every six months or so, you can do that with a bunch of really smart people in the room, manually looking at the data,” Harte said. “But if you want to bring that to hundreds of thousands of people, you have to automate that stuff.”

Stimo Results

One of the participants in the Stimo study is Michel Roccati, an Italian who became paralyzed after a motorcycle accident.

Harte said previous patients in the Stimo trials had some ability to move their legs, so the focus was on helping with the rehabilitation process and giving them “the missing parts of their walking habits”. Roccati couldn’t move his legs at all, but Harte said the results were “incredibly successful” and the man was able to walk again.

“First of all, it’s just because of his attitude. He’s an incredibly dedicated guy. He’s really motivated to do this,” Harte said.

After inserting a surgical implant into his spinal cord, the NeuroRestore team attached two remote controls to Roccati’s walker.

These controls were connected wirelessly via a tablet that transmits signals to a pacemaker in his abdomen, which then relays the signals to the implant that stimulates specific neurons.

“It triggers a left step or a right step. And if he does not trigger a separate step to the left, he engages a standing stimulation. So basically it gives him autonomy to walk.

NeuroRestore said the three patients involved in this trial followed a training regimen based on stimulation programs and were able to regain muscle mass, move more independently and participate in social activities like having a drink while standing in a bar.

On the medical front

Some of the possible products that could be created from these studies are presented by Onward Medical, a medical technology company that has a research partnership with NeuroRestore and participated in the Stimo study.

Onward is developing two technological platforms based on targeted nerve stimulation to try to solve several medical problems.

For example, the company’s ArcEx platform aims to improve physical movement of hand and arm function for people with spinal cord injuries. It is an external device that includes a wearable stimulator and a wireless programmer.

The other device, ArcIm, is an implantable pulse generator and lead placed near the spinal cord. This device was used in the Stimo study, but Onward believes it may help in other areas such as improving sexual function, bladder and bowel control.

Brain spine interface

One trial Harte said he’s excited about is NeuroRestore’s Brain Spine Interface study, which aims to digitally bridge the brain and spinal cord to restore motor control to paralyzed limbs.

Using various brain recording techniques such as electroencephalography, electrocorticography and intracortical recordings, the center said it is possible to decode motor intentions and translate them into targeted stimulations.

“There’s an implanted brain decoder, what you do is you remove parts of the skull and replace them with a sensor,” Harte explained. “Then you train pattern recognition algorithms to say, OK, think about wiggling your left leg, think about wiggling your toe, think about various things and it learns those brain states.

“And so it’s able to match what it’s sensing with the intentions, and then we turn those intentions into spinal cord stimulation.”

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