Clothing that can help people learn how to walk again after a stroke is the brainchild of a Harvard team reinventing the way we use robot technology

Conor Walsh’s laboratory at Harvard University is not your everyday research centre. There are no bench-top centrifuges, no fume cupboards for removing noxious gases, no beakers or crucibles, no racks of test tubes and only a handful laptop computers. Instead, the place is dominated by clothing.

On one side of the lab stands a group of mannequins dressed in T-shirts and black running trousers. Behind them, there are racks of sweatshirts and running shoes. On another wall of shelves, shorts and leggings have been carefully folded and labelled for different-size wearers. On my recent visit, one student was sewing a patch on a pair of slacks.

Walk in off the street and you might think you had stumbled into a high-class sports shop. But this is no university of Nike. This is the Harvard Biodesign Lab, home of a remarkable research project that aims to revolutionise the science of “soft robotics” and, in the process, transform the fortunes of stroke victims by helping them walk again.

“Essentially, we are making clothing that will give power to people who have suffered mobility impairment and help them move,” says Professor Walsh, head of the biodesign laboratory. “It will help them lift their feet and walk again. It is the ultimate in power-dressing.”

Last week, at a ceremony in Los Angeles, 35-year-old Walsh was awarded a Rolex award for enterprise for his work. He plans to use the prize money – 100,000 Swiss francs (about £82,000) – to expand “soft robotics” to develop suits that could also enhance the ability of workers and soldiers to lift and carry weights and also improve other areas of medical care, including treatments for patients suffering from Parkinson’s disease, cerebral palsy and other ailments that affect mobility.

Walsh is a graduate – in manufacturing and mechanical engineering – of Trinity College Dublin. While a student, he became fascinated with robotics after he read about the exoskeletons being developed in the United States to help humans handle heavy loads. Essentially, an exoskeleton is a hard, robot-like shell that fits around a user and moves them about. Think of the metal suit worn by Robert Downey Jr in Iron Man or the powered skeletal frame Sigourney Weaver used in Aliens to deal with the acid-dribbling extraterrestrial that threatened her spaceship.

“I thought that it all looked really, really cool,” says Walsh. So he applied, and was accepted, to study at the Massachusetts Institute of Technology (MIT) under biomechatronics expert Professor Hugh Herr. But when Walsh began working on rigid exoskeletons, he found the experience unsatisfactory. “It was like being inside a robotic suit of armour. It was hard, uncomfortable and ponderous and the suit didn’t always move the way a human would,” he says.

So when Walsh moved to Harvard, where he set up the biodesign lab, he decided to take a different approach to the problem. “I saw immediately that if you had a softer suit that accentuated the right actions, was comfy to wear and didn’t encumber you, it could have huge biomedical applications,” he says. “I began to wonder: can we make wearable robots soft?”

The answer turned out to be yes. Walsh, assisted by colleagues Terry Ellis, Louis Award and Ken Holt of Boston University, worked with experts in electronics, mechanical engineering, materials science and neurology to create an ingenious, low-tech way to boost walking: the soft exosuit. A band of cloth is wrapped around a person’s calf muscles. Pulleys, made from bicycle brake cables, are attached to these calf wraps and the other ends of the cables fitted to a power pack worn on a patient’s back. When the wearer starts to lift his foot to take a step, the power pack pulls the cables and this helps the wearer lift their leg. Then, as their foot swings forward, another cable, attached to the toecap of their shoes, tightens to help raise the toe so that it does not drag on the ground as they swing their legs forward. This condition is known as “foot drop” and it is a common difficulty for stroke patients.

In this way, an often critical problem for someone who can no longer control their muscles properly is alleviated. They can lift their legs and, just as importantly, keep their toes from turning down so that they do not drag on the ground and make them stumble. It is the perfect leg-up, in short.

“Designing robotic devices that target specific joints just hadn’t been done before,” says Walsh. “People had only looked at constructing a full-leg exoskeleton. We are targeting just one joint, not a whole leg. Crucially, in the case of strokes, it is the one that is often most badly impaired. Also, we have managed to keep our materials very light and easily wearable. Simple is best. That is our mantra.”

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Originally, the pulleys that lifted the cables that helped wearers’ raise their legs and toes were powered by a trolley-like device that trundled alongside them. One of the key improvements involved in Walsh’s project has been to reduce that power pack to a size that can be worn reasonable comfortably. The unit weighs 10lbs (4.5kg) and Walsh expects his team will be able to make further reductions in the near future. “Motors are going to get lighter, batteries are going to get lighter. That will all be of great benefit, without doubt.”

The packs are also fitted with devices known as inertial measurement units (IMU), which analyse the forces created by foot movements and raise and lower the brake-cable pulleys. These sensors have to work with millisecond accuracy for the system to work properly. “Timing is absolutely critical,” says Walsh.

Test runs have already proved successful, however. Videos of stroke patients wearing soft exosuits and walking on treadmills reveal a marked improvement in their movement. Once fitted with the suits, they no longer clutch the handrails and their strides become much quicker and more confident. “We are not saying our system is the only solution to impaired mobility,” adds Walsh. “There will always be a place for hard exoskeleton power suits, for example, for people who are completely paralysed. But for less severe problems, soft robotic suits, with their lightness and flexibility, are a better solution.”

Every year, about 110,000 people suffer a stroke in the UK. Most patients survive but strokes are still the third-largest cause of death, after heart disease and cancer, in this country. Strokes occur when the blood supply to the brain is stopped due to a blood clot or when a weakened blood vessel bursts. One impact affects how muscles work. As the Stroke Association points out, your brain sends signals to your muscles, through your nerves, to make them move. A stroke, in damaging your brain, disrupts these signals. Classic symptoms include foot drop and loss of stamina. Patients feel tired and become more clumsy, making it even more difficult to control their movements.

“Patients often withdraw from life. They stop going out and miss out on all sort of social events – their grandchildren’s sports events or parties,” says Ignacio Galiana of the Wyss Institute for Biologically Inspired Engineering at Harvard University, which is also involved in the soft exosuit project. “They prefer to stay at home and to stop exercising because it is so tiring and draining. They withdraw from the world. By making it possible to walk normally again we hope we can stop that sort of thing happening.”

The soft exosuits will not be worn all of the time, it is thought, but instead be put on for a few hours so patients can get out of their homes without exhausting themselves. The devices should also help in physiotherapy sessions aimed at restoring sufferers’ ability to walk. “This is a new tool that will greatly extend and accelerate rehabilitation therapy for stroke patients,” says Walsh. “Patients no longer have to think about the process of moving. It starts to come naturally to them, as it was before they had their stroke.”

As to timing, Walsh envisages that his team will be able to get their prototypes on to the market in about three years. Nor will soft exoskeleton use be confined to stroke cases. “Cerebral palsy, Alzheimer’s, multiple sclerosis, Parkinson’s, old age: patients with any of these conditions could benefit,” adds Walsh. “When muscles no longer generate sufficient forces to allow people to walk, soft, wearable robots will be able to help them.”

Source: https://www.theguardian.com/science/2016/nov/20/robot-exosuit-harvard-helps-stroke-sufferers-walk-again