Before he was director of the Human Engineering Research Laboratories, Rory Cooper was customizing his own wheelchairs for racing.
His racer was lighter than traditional chairs, optimized for racing on the road, but many of its modifications have since become commonplace in
Before he was director of the Human Engineering Research Laboratories, Rory Cooper was customizing his own wheelchairs for racing.
His racer was lighter than traditional chairs, optimized for racing on the road, but many of its modifications have since become commonplace in wheelchairs designed for everyday use. Cooper's chair demonstrated the importance of performance and functionality, ensuring that the user's quality of life is improved by restoring or augmenting as much of their capability as possible.
Ultralight wheelchairs, for example, not only increase wheelchair usability but reduce the risk of injury. Their light weight and ergonomics, developed through a focus on performance, led to designs that dramatically reduced instances of upper body injury, like rotator cuff and carpal tunnel injuries, in patients using manual chairs.
With the old designs, Cooper says, about 80% of manual wheelchair users developed these issues within five years.
"By understanding the ergonomics, the physiology, and also the interaction between the body and the wheelchair and the activity," he says, "that incidence is down to about 20%."
Hugh Herr, head of the awesomely-named Biomechatronics group at the MIT Media Lab and a double amputee himself, has developed multiple advanced prostheses that require no more metabolic energy than a natural limb --- a breakthrough in assistive technology. The Ottobock emPower ankle/foot prosthesis, for example, uses a robotic Achilles tendon and calf muscles to provide a push forward, leading to a more natural and stable gait.
"There's a deep, deep relationship between the functionality of the device and a person's identity of what their body is," Herr says. Although Herr believes that functionality alone is not enough to create that corporeal conception. The more that an assistive device is linked to the nervous system in a bidirectional way --- where the nervous system influences the prosthesis and vice versa --- the more a user feels the prosthesis to be part of their organic body, rather than merely an external tool.
Herr is studying not only brain control of synthetic motors but how sensory feedback from the bionic limb creates "neurological embodiment."
"That level of ownership and identity over the device completely changes the perception of how the person views the device, and whether they believe it is beautiful or not," Herr says. While the jury is still out, he theorizes that neuro-embodiment may be increased by devices which resemble biological features, like the emPower foot/ankle.
Hugh Herr, head of the Biomechatronics group at the MIT Media Lab.
“There’s a deep, deep relationship between the functionality of the device and a person’s identity of what their body is.”
High-level performance not only impacts how individuals perceive their assistive devices, but may also influence society's perception as well. Herr cites the blade-like prosthesis made famous by South African sprinter Oscar Pistorius as an example. While some devices that aren't "biomimetic" --- meaning they aren't designed to resemble an organic body part --- can inspire unwanted curiosity and attention (and even outright fear or aversion), if they achieve a certain level of performance, they can become something beautiful or awe-inspiring.
Seeing Pistorius flash his blades, slicing through space and time, the very unnatural-looking prosthesis transcends its appearance and becomes a magnificent tool, something to be praised for its performance and power --- the way that a Formula 1 car engenders awe when a Toyota Corolla does not.
Advanced Prosthetics Built to Use---and to Last
Function means little, however, if the device cannot hold up to consistent use.
"The fact that the person relies on the technology to replace or augment some function that is either impaired or no longer there means that (assistive technology) has super high reliability requirements," Cooper says. Since the loss of an assistive device can lead to a major impact on a user's quality of life, ensuring the devices work for as long as possible and with minimal maintenance is an important aspect of their design.
Durability must be balanced with