Soft wearable robotic exosuits can help patients walk after strokes, a new study finds. Stroke is the leading cause of disability in the United States. More than 6.5 million Americans are stroke survivors, and the vast majority of them never fully recover the ability to walk. "The fact that many stroke survivors can't, say, walk to the store can in turn lead to a downward spiral when it comes to their health and quality of life," Conor Walsh, a soft roboticist at Harvard University. Recent breakthroughs in exoskeleton technology have shown promise as advances over canes, walkers, orthotics, and other traditional aides for stroke patients.

Thanks to science fiction, we can't think about artificial intelligence without summoning the ghost of 2001: A Space Odyssey's killer AI HAL 9000; we have to make the obligatory Terminator reference in any story about cutting edge robots; and the picture that immediately springs to mind when we mention robotic exoskeletons are bulky pieces of kit straight out of Iron Man or the underrated Tom Cruise flick Edge of Tomorrow. However, when it comes to that last research topic, investigators at the Harvard Biodesign Lab are doing everything they can to change our perceptions and convince us that robotic exoskeletons don't have to be rigid cages surrounding a person's limbs, applying torque directly to their joints to aid them with a specific motion. While this approach can be hugely promising in helping individuals with paraplegia, it's less necessary in other scenarios. For example, in situations where you have an individual with gait impairments, but who still has function in their lower limbs (such as a post-stroke patients or individuals with multiple sclerosis), applying the same approach is a bit like using a sledgehammer to crack a nut. The considerable weight of rigid exoskeletons and the energy expenditure they therefore prompt in the person wearing them isn't something to be sniffed at.

Last year, US Army-funded plans for a flexible exosuit designed to help soldiers carry heavy loads were revealed. Now, a new study has shown exactly how much energy the soft exosuit can save. Results published in a new paper show the suit reduces the effort it takes to walk by 23 per cent, by assisting the wearer's ankles and hips every time they take a step. The suit reduces the effort it takes to walk by 23 per cent, by assisting the wearer's ankles and hips every time they take a step. The Harvard suit comprises a waist belt, two thigh pieces and two calf straps, connected by cables to two motors mounted on a backpack.

Those leg motors include sensors to detect "the slightest intention of movement," and an onboard computer then follows the child's steps to create the smoothest mechanical gait possible. Because children are constantly growing and moving, the whole setup is designed with telescoping supports that get taller with the patient. CSIC's "smart" approach is similar to the algorithm that SRI Ventures recently built into the Superflex soft exosuit, and with a little tweaking the algorithm could probably help extend the CISC suit's five-hour battery life. Finally, the CISC is currently testing the exoskeleton with three child volunteers in Madrid and Barcelona, but in the U.S., Harvard engineers have teamed up with ReWalk Robotics to test and eventually market a similar, soft exosuit designed for adults with limited mobility.