Almost 18,000 Americans experience traumatic spinal cord injuries every year. Many of these people are unable to use their hands and arms and can't do everyday tasks such as eating, grooming or drinking water without help.
In a small study of physical therapy combined with a non-invasive method of stimulating spinal-cord nerve cells, University of Washington researchers helped six Seattle-area participants regain some hand and arm mobility. That increased mobility lasted three to six months after treatment ended. The research team published the findings in the journal IEEE Transactions on Neural Systems and Rehabilitation Engineering.
Research participant Jon Schlueter works with Dr Fatma Inanici, as she tests his motor skills early in the study. Image credit: Marcus Donner/Center for Neurotechnology
“We use our hands for everything — eating, brushing our teeth, buttoning a shirt. Spinal cord injury patients rate regaining hand function as the absolute first priority for the treatment, five to six times more important than anything else that they ask for help on,” said lead author Dr Fatma Inanici. She completed this research as a doctoral student of rehabilitation medicine in the UW School of Medicine.
“At the beginning of our study,” Inanici said, “I didn't expect such an immediate response starting from the very first stimulation session. As a rehabilitation physician, my experience was that there was always a limit to how much people would recover. But now it looks like that's changing. It's so rewarding to see these results.”
After a spinal cord injury, many patients undergo physical therapy to try to regain mobility. Recently a series of studies showed that implanting a stimulator to deliver electric current to a damaged spinal cord could help paralyzed patients walk again.
The researchers from the Center for Neurotechnology combined stimulation with standard physical therapy exercises. The nerve stimulation, however, does not require surgery. Instead, it involves small patches stuck like Band-Aids to a participant's skin around the injury site, where they deliver electrical pulses.
The researchers recruited six people with chronic symptoms from spinal injuries. All participants had been injured for at least a year and a half. Some participants couldn't wiggle their fingers or thumbs while others had some mobility at the study's outset.
To explore the viability of skin-surface stimulation, the researchers designed a five-month training program. In the first month, the researchers monitored participants' baseline limb movements each week. In the second month, the team put participants through intensive physical therapy three times a week for two hours at a time. In the third month, participants continued physical therapy training and added neural stimulation.
“We turned on the device, but they continued doing the exact same exercises they did the previous month, progressing to slightly more difficult versions if they improved,” Inanici said.
For the last two months of the study, participants were divided into two groups: Those with less severe injuries received another month of training alone and then a month of training plus stimulation. Patients with more severe injuries received the opposite — training and stimulation first, followed by training-only.
Some participants regained some hand function with training alone, and all six saw improvement when stimulation was combined.
Among the participants, Jessie Owen had lost use of her hands in a car accident five years ago, and Jon Schlueter had lost use of his hands after a diving accident 13 years ago. Both regained mobility in their hands, as this YouTube video shows. Download pictures and videos from here.
“Both people who had no hand movement at the beginning of the study started moving their hands again during stimulation, and were able to produce a measurable force between their fingers and thumb,” said senior author Chet Moritz, an associate professor of electrical and computer engineering and of rehabilitation medicine and physiology. “That's a dramatic change, to go from being completely paralyzed below the wrists down to moving your hands at will.”
Some participants noticed other improvements, including a more normal heart rate and better regulation of body temperature and bladder function.
The team followed up with participants for up to six months after training and found that the improvements remained, despite lack of continued stimulation.
“We think these stimulators bring the nerves that make your muscles contract very close to being active. They don't actually cause the muscle to move, but they get it ready to move. It's primed, like the sprinter at the start of a race,” said Moritz, who co-directs the Center for Neurotechnology. “Then when someone with a spinal cord injury wants to move, the few connections that might have been spared around the injury are enough to cause those muscles to contract.”
The results of this study have already informed the design of an international, multisite clinical trial that will Moritz will co-lead. UW Medicine will be one of the sites.
“We're seeing a common theme across universities: Stimulating the spinal cord electrically is making people better,” Moritz said. “But it does take motivation. The stimulator helps you do the exercises, and the exercises help you get stronger, but the improvements are incremental. Over time, however, they add up into something that's really astounding.”
Source: University of Washington