Wearable airbag helps prevent hip fractures

A re-usable airbag, worn in a belt that opens when the wearer begins to fall, is being developed by scientists in the Netherlands.

Hip fractures in the elderly, mostly caused by falls, are a major problem world-wide, with each instance in the developing world costing the public purse thousands of dollars, while accelerating the decline in the health of sufferers.

Old people are at high risk of such an injury because our bones weaken with age, sometimes leading to osteoporosis.

Dutch entrepreneur Filippo van Hellenberg Hubar came up with the idea for a belt, and three years ago approached Dr. Heike Vallery, associate professor in biomechanical engineering at his old university, Delft University of Technology (TU Delft), to help develop it.

Vallery and her colleagues at the Faculty of Mechanical, Maritime and Materials Engineering (3mE), are experts in human walking and gaits.

Her team is developing algorithms that can predict when an elderly person will fall and these have been incorporated by van Hellenberg Hubar into his Wolk airbag prototype, which he hopes to bring to market in 2017.

"Unlike the airbags used in cars that are single use, our product will be used more often because our target group falls, on average, two to three times a year, so the Wolk is actually a re-usable product. When a fall is detected the system activates and the gas capsule releases the gas into the airbag component. After this has happened you can fold the airbag component back in, insert a new inflator, and the whole system is good to go again."

Inside the Wolk, which can be worn under most clothes, are three integrated sensors, positioned at the belt's rear and both its sides, with each programmed by Vallery's team to detect a fall.

"We try to take as much as possible from the information that we get from the sensors in this belt, in at least three locations," explained Vallery. "They are in the front and the back of your body, and thereby we can calculate accelerations and angular velocities of the body - and combined with our models of how humans move we can detect whether there is a fall about to occur or not. Then we have a little microprocessor inside, which processes the information and inflates the airbags."

Avoiding so-called 'false positives' has been difficult.

"It's quite challenging to detect a fall, but it's just as challenging to avoid mis-detections of falls, when people are just making movements that seem like falls," explained Vallery. "For example, when elderly people sit down they tend to often just slump in the chair and that kind of movement could easily be confused with a fall. So we combine all the knowledge we have on how humans behave normally with the little sensor information that we get in order to distinguish between normal movements and when someone is about to fall."

Tests so far have concentrated on healthy, young, actors trained to simulate the walking movements in the elderly and such behaviour as slumping into a chair, turning, or bending. Volunteers have also tumbled onto a mat repeatedly to help researchers create their algorithms.

The next stage of testing will involve testing 20 volunteers wearing the Wolk (which translates as Cloud in Dutch) in each of five separate nursing homes. A month of testing the 100 volunteers wearing the belt should be enough to perfect the Wolk's design, says van Hellenberg Hubar.

He believes the likely cost of around 450 euros (480 USD) per belt, plus a small fee for individual gas canisters, will be money well spent if rolled out in nursing homes and private homes. Van Hellenberg Hubar says the average cost of the first year of medical care following a hip fracture is 40,000 euros (43,000 USD), including hospitalisation, emergency procedures, and rehabilitation.

"One of the important issues that we worked on is to make this product so comfortable that people can wear it whenever they want," van Hellenburg told Reuters. "The problem with prior hip protectors is that they were bulky, often uncomfortable, and therefore people were not using them."

Professor James Goodwin, chief scientist for British elderly person's charity Age UK, said the device could have multiple benefits.

"If this device is trialled properly and is taken into the marketplace I think the impact of it could be very high, with a lot of benefits to older people and to health systems," he told Reuters. "Globally we're talking about many thousands of falls every day, with huge healthcare costs the world over - and anything that can mitigate those and reduce those will be exceptionally welcome. Not least of all, older people themselves will really welcome this device if it's going to prevent them suffering the pain and long-term injuries that result from falling over."

Goodwin said that technology itself was not a silver bullet, though, and that preventive health measures were necessary among the population before they become elderly and infirm, in addition to the authorities making public environments safe.

"What we shouldn't do is pin all our hopes on a single piece of technology," he said. "Technology is great because it moves us forward incrementally and I suppose if you went into hospital in the 1950s and you went into a hospital today they would appear worlds apart, and the answer to that is technology. But in itself one piece of technology is not going to solve a problem."

The Delft-Wolk team thinks preventing hip and wrist fractures will keep elderly people active for longer, preventing them from fearing walking, a process that causes loss of independence.

Additional features such as an alarm system which can tell when someone has fallen and is lying on the ground are planned, automatically sending a message to the emergency services. — Reuters