The proverbial story of overcoming paralysis tends to start with the legs: Superman vows to walk again; a soap opera character steps out of their wheelchair. “I think society has a tendency to focus solely on the walking aspect of disability,” says Ian Ruder, a magazine editor with the United Spinal Association, a nonprofit advocacy group for people with spinal cord injuries and disorders. But Ruder, who has used a wheelchair following an injury 23 years ago, says even restoring just a fraction of his hand function would improve his quality of life more than walking. “The difference between being able to pinch with my thumb and not be able to pinch with my thumb is hard to understand for most people,” Ruder says. “That would unlock a whole new level of independence.”
Ruder isn’t alone in feeling that way. Surveys of people with quadriplegia find that they rate regaining hand, bladder, core, and sexual function as higher priorities than walking. Yet effective and accessible technologies for restoring motor function to a person’s own upper limb—rather than via a prosthetic device—have been scarce. Earlier this month, however, researchers from the University of Washington’s departments of rehabilitation medicine and electrical and computer engineering reported that they’d restored some hand function in six people using an electrical current delivered through patches on their necks. The benefits emerged quickly and lasted for several months after the trial without continued stimulation—all without any invasive surgery.
“It’s totally exciting,” says Ruder, who was not involved in the study. “The possibility of restoring function with such a noninvasive and simple approach is huge.”
The lower body, especially the limbs, get more research attention, in part because arm and hand movement is a more complicated dance of motor neurons, muscles, and joints. Researchers have tried to replace or restore that function with a gamut of technologies, from brain-computer interfaces (BCIs) and prosthetics to electrical stimulation for nerves and muscles. Implanted BCIs show promise, but they require surgery to position a chip that reads brain activity, translates it into usable commands, and is worn long-term—and there are costs and infection risks associated with that. Fatma Inanici, a rehabilitation and neuroscience researcher in the Chet Moritz Lab at the University of Washington and lead author of the study, works on something more accessible. “Instead of doing surgery,” she says, “you can put the electrodes over the skin and turn on the device to stimulate the spinal cord.”
Inanici’s work, published in IEEE Transactions on Neural Systems and Rehabilitation Engineering, builds on earlier evidence that getting current into the spinal cord improves mobility. Her team’s trial tested whether pairing that stimulation with physical rehabilitation training for the participants’ hands would allow them to accomplish activities that they couldn’t achieve with training alone. Six people paralyzed by spinal cord injuries joined the trial, each with a range of different abilities, from nearly no hand function to over 50 percent. For a month, they worked each week with a personal coach, pinching beads, stacking blocks, and tying knots. But rehab only got them so far. “All of these things were frustratingly difficult for me,” says Jessie Owen, a teacher from Washington and one of the participants. “I didn’t make much progress.”
The next month, Inanici and her team stuck two flexible round hydrogel electrodes to the back of each participant’s neck, right above the collar. Each patch was about as flat and wide as a quarter, and wired to a stimulator the size of a chunky old cell phone.