Seemingly simple things like talking to people at eye level and reaching things on shelves can be a huge drawback for those in wheelchairs. Sitting in a wheelchair for extended periods can also lead to the increased risk of certain infections and blood circulation problems. A robotic exoskeleton called REX puts wheelchair users back on their feet, enabling a person to stand, walk and go up and down stairs and slopes.

Since that’s where the money is, the he main focus of robotic exoskeletons has generally been in seeking to increase the capabilities of military ground personnel – one example being the HULC powered robotic exoskeleton from Lockheed Martin. When Robert Irving was diagnosed with Multiple Sclerosis it was the catalyst for him and his childhood friend, Richard Little, to put turn their engineering skills to the task of developing an exoskeleton that was a practical standing and walking alternative to wheelchairs.

The result is REX, an exoskeleton made of strong, lightweight materials that is designed to support and hold a person comfortably as they move. Users strap themselves in to the robotic legs with a number of Velcro and buckled straps that fit around the legs along with a belt that fits around the user’s waist. While most robotic exoskeletons we’ve looked at, such as the HAL, augment human motion, this is generally not an option for wheelchair-bound users so REX is controlled using a joystick that sits at the wearer’s waist level.

Upward mobility

When wearing REX users can stand up, walk, move sideways, turn around, go up and down steps, as well as walk on flat, hard surfaces including ramps and slopes. It is powered by a custom-made rechargeable battery that will typically provide two hours of active use on a full charge. To extend running time the battery can be easily swapped out for a fully charged one.

Little and Irving formed a company called Rex Biotics which produces the REX in Auckland, New Zealand. The company is in the process of concluding all the tests required prior to putting REX on the market in Europe and Australia. It will also be seeking FDA approval so that REX can be put on the market in the USA.

Not for everyone

Before purchasing the REX, potential customers will need to complete a medical check with their own physician as well as a series of checks for range of motion with a qualified physical therapist to ensure they have no contraindications to standing and walking. To meet REX’s balance and loading constraints, customers will also need to be between 4’8” (146cm) and 6’4” (195cm) tall, with a weight of less than 220lb (100kg) and a hip width of less than 15” (380mm). Rex Biotics will also provide full training and a customized fitting over the course of approximately two weeks for buyers of the device.

The company says REX is only really suitable for manual wheelchair users who can self-transfer and operate hand controls and REX’s developers are quick to point out that REX is not intended as a replacement for a wheelchair, but as a complement to a wheelchair.

Tick of approval

One of the first people to try REX is Hayden Allen, who suffered a spinal cord injury and became a full-time wheelchair user with doctors telling him he would never walk again.

“I’ll never forget what it was like to see my feet walking under me the first time I used REX,” says Hayden, who is 6’4” (193cm) tall when standing. “People say to me, ‘look up when you’re walking’ but I just can’t stop staring down at my feet moving.”

Allen can be seen using REX in the video below, and it’s hard to argue against the potential for the device when looking at the smile on his face.

Regarding REX, Dr Richard Roxburgh, Auckland neurologist and Medical Advisor to the Muscular Dystrophy Association says, "For many of my patients REX represents the first time they’ve been able to stand up and walk for years. There are obvious immediate benefits in terms of mobility, improved social interaction and self-image. There are also likely to be major long-term health and quality of life benefits through reducing the complications of being in a wheelchair all the time. I think that this will also enable people to stay well longer; this means that those who have conditions where disease modifying treatments are coming over the next five to ten years, will be in better shape when those treatments finally arrive.”

Rex Bionics CEO, Jenny Morel, says the company expects to conclude internal testing of REX shortly and will then have a preliminary release in Auckland to allow the company to track what happens when people take REX home. Sales are expected to commence in New Zealand by the end of 2010 and elsewhere by the middle of 2011. It is expected to cost about US$150,000.

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