In a first, a robotic exoskeleton device has enabled a 39-year-old former athlete who had been completely paralysed for four years to voluntarily control his leg muscles and take thousands of steps, US scientists say.
This is the first time that a person with chronic, complete paralysis has regained enough voluntary control to actively work with a robotic device designed to enhance mobility, said researchers from the University of California - Los Angeles (UCLA).
In addition to the robotic device, the man was aided by a novel noninvasive spinal stimulation technique that does not require surgery. His leg movements also resulted in other health benefits, including improved cardiovascular function and muscle tone.
The new approach combines a battery-powered wearable bionic suit that enables people to move their legs in a step-like fashion, with a noninvasive procedure that the same researchers had previously used to enable five men who were completely paralysed to move their legs in a rhythmic motion.
That earlier achievement is believed to be the first time people who are completely paralysed have been able to relearn voluntary leg movements without surgery.
The researchers do not describe the achievement as "walking" because no one who is completely paralysed has independently walked in the absence of the robotic device and electrical stimulation of the spinal cord.
In the latest study, the researchers treated Mark Pollock, who lost his sight in 1998 and later became the first blind man to race to the South Pole.
In 2010, Pollock fell from a second-story window and suffered a spinal cord injury that left him paralysed from the waist down.
At UCLA, Pollock made substantial progress after receiving a few weeks of physical training without spinal stimulation and then just five days of spinal stimulation training in a one-week span, for about an hour a day.
"It will be difficult to get people with complete paralysis to walk completely independently, but even if they don't accomplish that, the fact they can assist themselves in walking will greatly improve their overall health and quality of life," said V Reggie Edgerton, a UCLA distinguished professor of integrative biology and physiology, neurobiology and neurosurgery.
The procedure used a robotic device manufactured by California-based Ekso Bionics which captures data that enables the research team to determine how much the subject is moving his own limbs, as opposed to being aided by the device.
The data showed that Pollock was actively flexing his left knee and raising his left leg and that during and after the electrical stimulation, he was able to voluntarily assist the robot during stepping; it was not just the robotic device doing the work.
"For people who are severely injured but not completely paralysed, there's every reason to believe that they will have the opportunity to use these types of interventions to further improve their level of function," Edgerton said.
