Wearable exoskeleton helps paraplegics walk
Over a year ago we reported about a smart lower-limb prosthetic developed by researchers at the Vanderbilt University, and they recently presented a powered exoskeleton that enables people with severe spinal cord injuries to perform tasks such as standing, walking, sitting and climbing stairs. Although these exoskeletons haven’t yet been approved for home use, their light weight, compact size and modular design make them a noteworthy challenger of currently existing competitors.
Led by Michael Goldfarb, the H. Fort Flowers Chair in Mechanical Engineering and professor of physical medicine and rehabilitation at Vanderbilt, the researchers designed an exoskeleton which operates in a way similar to Segways. It picks up cues such as leaning forward or back in order to move forward, stand up or sit down.
Vanderbilt design has a modular design and it is lighter and slimmer compared to its currently available competition, thus making it more suitable for every day use where it grants greater degree of independence as well as easier transport since it can be snapped apart and transported by wheelchair. Weighting about 12.25kg (27 lbs), the exoskeleton developed at Vanderbilt is nearly half the weight of other currently available models from the competition.
Aside previously mentioned advantages the exoskeleton offers robotic assistance which automatically adjusts for users who have some muscle control in their legs. This allows the users to use their leg muscles activity rather than leaning in order to control the exoskeleton.
It is the also the only currently available wearable robot that incorporates a proven rehabilitation technology called functional electrical stimulation (FES). FES is a method used for patients with incomplete paraplegia where it uses small electrical pulses to paralyzed muscles, causing them to flex and gain back the strength. FES can also be used for patients with complete paraplegics, where it is used to improve circulation, change bone density and reduce muscle atrophy.
“These new devices for walking are here and they are getting better and better. However, a person has to be physically fit to use them”, said Clare Hartigan, a physical therapist at Shepherd Center where Vanderbilt devices are tested. “They have to keep their weight below 220 pounds [100kg], develop adequate upper body strength to use a walker or forearm crutches and maintain flexibility in their shoulder, hip, knee and ankle joints … which is not that easy when a person has relied on a wheelchair for months or even years.”
Persons suitable for use of this exoskeleton strap it in tightly around the torso. Rigid supports strapped to the legs and extend from the hip to the knee and from the knee to the foot are connected with hip and knee joints which are driven by computer-controlled electric motors powered by advanced batteries. In order to maintain balance, patients use the Vanderbilt exoskeleton with walkers or forearm crutches.
The university has several patents pending on the design and Parker Hannifin Corporation has signed an exclusive licensing agreement to develop a commercial version of the device, which should be introduced in 2014. Parker Hannifin hasn’t set a price for the Vanderbilt exoskeleton, but Goldfarb is hopeful that its minimalist design combined with Parker Hannifin’s manufacturing capability will translate into a product which will be affordable by individuals.