Standing, walking, climbing stairs – these are activities that many people take for granted. Yet, for some people who experience spinal cord injuries, even taking a few steps may be impossible.
A new device could change that. It has already allowed patients who had a complete loss of voluntary movement below their spinal cord injuries to stand up and take steps, according to a study published Monday in the Nature Medicine journal.
“Within a single day, activity-specific stimulation programs enabled these three individuals to stand, walk, cycle, swim and control trunk movements,” said the study. Researchers said the technology may be commercially available in three to four years.
All three participants in the STIMO clinical trial, led by Dr. Jocelyne Bloch from Lausanne University Hospital and Grégoire Courtine of the Swiss Federal Institute of Technology, were men age 29 to 41, according to CNN. Overall, 16 electrodes were surgically implanted between the men’s vertebrae and spinal cord membrane, along with pacemakers implanted under the skin of their abdomens.
These pacemakers sent currents to the electrodes. Researchers used a tablet computer to “initiate unique sequences of electrical pulses,” that activated the patient’s muscles through the device, said CNN.
“It's a very emotional moment, because [patients] realize they can step,” Bloch said.
While the electrodes can stay in place for life, the pacemaker must be replaced after nine years.
“I am free,” said Michel Roccati of Italy, one of the study participants.
He lost the ability to walk in 2017 after a motorcycle accident left him with a complete spinal cord injury. “I can walk wherever I want to.”
People with the STIMO device can regain voluntary movement only when they are receiving stimulation. When the device is off, the movement is no longer possible.
Roccati and the other study patients received one to two hours of physical therapy four times a week after their surgeries. As they trained with the device, the patients built up greater endurance for more activities. One participant could stand for two hours at a time, another could walk for 500 meters independently and another climbed up stairs.
“The more they train, the more they achieve, so they need the motivation to be able to stand a long time,” Bloch said.
Researchers have been investigating the use of electrical stimulation for spinal cord injuries for around 30 years. What sets the recent study apart is its electrode array, developed by Onward Medical. According to CNN, the array is wider and longer than those used in similar studies.
Bloch said it allows access to a broader area of the spinal cord to stimulate both trunk and leg muscles. The researchers also developed an algorithm to optimally place the array.
Dr. Nandan Lad, a neurosurgeon at Duke University who was not involved in the study but conducts similar research, said the precise neurosurgical placement of the electrodes is key to the study’s ability to stimulate necessary muscle groups so quickly. Indeed, the study is the first report of complete spinal injury patients taking steps on a treadmill just a day after surgery.
Previous studies have relied on participants’ intent to move and the brain signals that follow. This study uses a timed sequence of stimulations generated using motor responses to electric jolts.
“These pre-established sequences trigger movement and attempt to mimic the natural pattern of muscle activation needed to walk,” said CNN.
Study researchers redesigned technology initially used to alleviate pain by targeting spinal cord roots.
Earlier studies out of the University of Louisville demonstrated that people who were completely paralyzed but still had sensation could walk again with several months of rehabilitation through electrical stimulation to the spinal cord.
Researchers who conducted the recent study plan to work with Onward Medical to adapt the device for everyday use and integrate its programs into smartphones and smartwatches. They also plan to scale up clinical trials in the U.S.
Onward “has has received three Breakthrough Device Designations from the [U.S. Food and Drug Administration],” for research and an FDA pivotal trial with 65 subjects completed enrollment in December, said a press release.
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