The researchers recently demonstrated in a study that the exoskeleton -- which looks more like superhero armor than medical equipment -- was safe and well-tolerated and could be worn while the children walked on their own.
"Our exoskeleton provides assistance to improve upright posture when worn while still requiring the person to control their own muscles and stability," said Diane Damiano, chief of the Functional and Applied Biomechanics section in the NIH Clinical Center's Rehabilitation Medicine Department and a co-author of the study.
"Children with cerebral palsy have a physical disability that persists their entire life, so they need to be continuously monitoring and working to maintain their motor functioning as part of their everyday lives," she said. "Wearable devices could provide a novel mechanism to do this."
Cerebral palsy is caused by abnormal development in the part of the brain that controls movement. Although there is no cure, supportive treatments, medications and surgery
can help improve motor skills.
In the US, cerebral palsy is the most common motor disability in childhood, affecting about one in 323 children, according to the Centers for Disease Control and Prevention
. In the United Kingdom, about one in 400 children has a type of cerebral palsy, according to the National Health Service
'The children were pretty excited'
The recent exoskeleton study involved seven children with cerebral palsy, 5 to 19 years old, who all had some difficulty walking due to crouch gait, in which the knees are excessively flexed.
Over a period of about eight to 12 weeks, each child was tested in the exoskeleton and practiced walking with the technology in a lab across the floor and on a treadmill during six visits with the researchers. Each visit lasted about a couple of hours, of which about 30 minutes to an hour was spent walking over ground.
The researchers found that, as the children walked across the lab floor, the exoskeleton reduced crouch by changing their posture and assisting in the extension of their knees.
While wearing the exoskeleton, six of the seven children showed posture and walking improvements equivalent to or greater than improvements typically seen from invasive orthopedic surgery, the researchers noted in the study.
"Most of the children were pretty excited to feel the way that this device changed how they walked," said Thomas Bulea, staff scientist in the center's Rehabilitation Medicine Department and lead author of the study.
"More striking was the reaction we saw on a lot of the parents' faces," he said. "Several, if not most of them, expressed surprise at the visible effects of the exoskeleton during walking."
Yet more research is needed before robotic exoskeletons could be made available to children with cerebral palsy nationwide.
After all, the study involved a small number of participants. The robotic exoskeleton needs to be tested with many more children before it could be made widely available, Bulea said.
"The biggest limitation is that this was a relatively small study," he said, adding that it involved only children with crouch gait from cerebral palsy who were able to walk on their own without crutches or a walker.
"So generalizing the results of the study beyond the sample with that inclusion criterion should be done with caution," he said, adding that the researchers plan to continue testing the exoskeleton on other children and conditions.
"The big question that we're looking to answer going forward is, how do these improvements in walking and muscle activity that we see with the exoskeleton affect their walking in the long term?" Bulea said.
"How does it, or does it, change their walking pattern when they're not using the exoskeleton? And that's a question that is still very much open," he said. "We're still a long way off from this being a commercially available product. We're excited by the promise that this initial study showed, but we still have to do more studies to establish the effectiveness of this as a rehabilitation device."
'In the future, I expect we will see more and more exoskeletons'
Steven Collins, associate professor of mechanical engineering at Stanford University, called the results "very promising."
"The exoskeleton was able to reduce crouch to a similar degree as some surgeries, without being invasive," said Collins, who was not involved in the study.
Yet the long-term impact of using exoskeletons remains to be tested, he said.
In the study, children did not use the exoskeleton over a prolonged time period, Collins said, and the data showed that there was some muscle resistance to the device even though it was improving their posture.
"It's not clear whether that would change with prolonged use," Collins said.
"In the future, I expect we will see more and more exoskeletons like this used in children's medicine," he said. "Exoskeletons are versatile and controllable, so they can adapt alongside their users. In some cases, this may make them better than surgery."
Michael Goldfarb, who has developed lower-limb exoskeletons for adults
paralyzed below the waist with his team, said he often receives emails and phone calls from parents of children with cerebral palsy asking whether such devices are available for youngsters.
"So I'm really happy to see that this group has done the work that they have," said Goldfarb, a professor and director of the Center for Intelligent Mechatronics at Vanderbilt University, who was not involved in the study.
"If my children had cerebral palsy, I would want to do everything I could so that their lives would be minimally impacted by it," he said.
However, he added, more work is needed.
"Children grow so fast," Goldfarb said. "You have to have devices that can be light but also adjustable as far as size if you're going to keep working with children of different sizes and different ages."