New bionic legs help paraplegics walk again

Stephanie Sablan tries out eLegs in a bid to regain mobility

Stephanie Sablan was driving home from her grandmother’s house late at night last January, down the scenic Route 101 in Northern California. Sablan picked up her phone and typed a text message to her boyfriend to say she’d be there in half an hour. Before she hit send, she looked up and was surprised by a curve in the road. She swung the steering wheel to avoid the central reservation, but went too far, and the car flipped over – once, twice, three times, four times.

As the car tumbled, Sablan was thrown out of the passenger-side window – “I wasn’t wearing my seat belt,” she says – and landed in the grass beside the highway. “I tried to get up, but I couldn’t move my legs.”

Sablan, 24, is now paralysed from the waist down. But six months after the accident, she is walking again, with the help of a bionic device that interprets arm gestures to move the legs.

At a physical therapy session at Santa Clara Valley Medical Center, Sablan practises using eLegs, this new device. An artificially intelligent computer strapped to her back processes the intention of movements in her arms and sends a signal to the motorised braces on her hips and legs to step forward. In a swift movement, one knee bends and her heel lifts up and settles on the floor, almost as naturally as it did before her accident.

It will be at least another two years before people like Stephanie Sablan will be able to have a pair of eLegs at home, where the device’s designers hope it will enable people to perform normal daily functions, such as walking to the bathroom to brush their teeth, or to the car to drive to work.

The device was put through its first trials in San Jose this spring, and will roll out to a total of 10 rehabilitation centres across the US this year. Dr Akshat Shah, who is overseeing the study, hopes that one day he’ll be able to send his patients home with a set of electronic legs instead of a wheelchair.

“For spinal cord injury, we haven’t had a major breakthrough in 20, 30 years,” says Dr Shah. “This could be a game changer.”

The bionic exoskeleton was first developed at Berkeley Bionics – a robotics lab located about 90 miles north of where Stephanie Sablan had her car accident – by graduate students from the University of California at Berkeley. As the engineers fine-tune the software in eLegs, Berkeley Bionics’ chief executive Eythor Bender imagines an even broader range of uses – and markets – for exoskeletons such as these in the future.

“There are stroke victims and the ageing population,” Bender said. “Maybe there’s a simpler version of eLegs to help those with arthritis get around.”

Another device the company designed for the military, to help soldiers carry heavy loads, could be extended to firefighters or postal workers. “We look at ourselves as a company that is mastering the merger of the man and the machine,” Bender added.

At this stage of her rehabilitation, Sablan’s eLegs are used primarily to boost her strength. Walking in the device in a square around the rehabilitation centre constitutes a serious workout: her arm muscles flex, her breath quickens and the sweat builds up on her brow.

“Make-up!” she calls, in jest, her humour undimmed by her disability. Her mother brings a small towel and blots Sablan’s forehead as she catches her breath. As she adjusts her arms in the crutches to start again, the tattoo on her inner right forearm ripples over her tendons. “No pain … fight forever,” it reads in neat cursive.

These were the words Lady Gaga uttered in a voicemail message to Sablan the night before she tried eLegs for the first time. Yes, the Lady Gaga. Sablan is a huge fan, and when her friends saw the iconic rock star in concert the night before Sablan’s eLegs trial, they persuaded Lady Gaga to call Sablan to wish her luck.

The tattoo is the latest of six Sablan has had. She gets one every year on her birthday, to commemorate what she’s been through the previous year. The notion of fighting for ever seemed appropriate when she turned 24 in March, a couple of months after losing the use of her legs, and a couple of weeks after learning to use them again with eLegs.

“To just be standing up and not sitting down is pure bliss,” she says.

April Dembosky is the FT’s San Francisco correspondent

Jackson Pollock: physicist (and painter)

The American abstract expressionist artist Jackson Pollock, once dubbed “Jack the Dripper” by Time magazine, was in fact a “stream painter” who harnessed fluid dynamics as his co-author, according to a new analysis of his work.

A study in Physics Today by a team from Boston College and Harvard University argues that Pollock “creatively ceded some of the responsibility for the appearance of his work to natural phenomena”.

The academics – two physicists and one art historian – argue that Pollock focused less on incidental drop splashes than on flowing continuous lines, and that he dispensed pigment in a “refined” way to control the flow rate. By changing the lateral speed, flow rate and height of the jet, he was able to vary the width of his traces and have the freedom to paint in three dimensions.

By analysing the tight loops and coils in his painting “Untitled 1948-49”, the authors suggest Pollock was exploring the role of fluid instabilities: “Pollock’s arm was slowing down while turning … he purposefully varied the conditions in order to elicit coiling instability in his viscous jet.”

Whether their deductions will be of potential use to future physics-inclined artists is open to debate. But at the very least, as they conclude: “Using the tools of physics and art history, one may begin to delineate the intersection of what is aesthetically viable and what is physically possible.”

Taking steps to make school children fitter

While children from deprived backgrounds are often perceived to be at greater risk of obesity, a new study suggests that they may be more likely than their more privileged contemporaries to benefit from taking healthier forms of transport to school.

Medical experts have long believed that a shift towards children being driven to school has contributed to the obesity epidemic. The proportion of American students who walk or cycle to class has fallen from more than two-fifths to less than one-sixth in the last three decades of the 20th century.

Physical activity typically increases up to age 10, as parents become more confident in their children. But it drops off once they reach secondary school, when they normally travel further.

Yet in an article in Pediatrics, academics from the University of Montréal showed that among 7,700 Canadian students in the public school system, “active transport” is more widespread among poorer families than among their richer counterparts.

The researchers found more walkers and cyclers among urban than rural children; among those from families with “inadequate incomes”; and those from single-parent families. Children with an older sibling also adopted healthier modes of transport.

The study could suggest the importance of public health education measures to encourage cycling and walking into secondary education.

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