Life on Wheels (54 page)

Finally, think about how the effort needed to operate a manual chair will affect your health in the long run. Many manual chair riders with 20 or so years of pushing behind them find that their shoulders begin to give out. You are better off using a manual chair if you can, but not at the expense of your longterm health.

A special category of power wheelchairs is the outdoor chair. They have stronger motors, bigger batteries, independent suspension for rough terrain, and wider tires all around with deeper tread for traction. Teftec was the first company to develop an outdoor chair, after 14-year-old Jimmy Finch had his neck broken in an auto accident, hit by a drunk driver. It was a high-level injury, allowing Jimmy no use of his hands or arms.

Teftec was born when, after attending a variety of expo shows and wheelchair workshops, Jim and his father took up the challenge of designing an outdoor power wheelchair that could be driven by someone independently who had high quadriplegia. The result was the OmegaTrac
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frontwheel drive, heavy-duty wheelchair, first introduced at the MedTrade medical products show in 1995 in Atlanta. Being engineered and manufactured for great strength, Teftec has also found an audience in people who are large. www.teftec.com.

Many people with low-level quadriplegia have sufficient arm strength to push a chair, perhaps aided by handrims with knobs that are easier to grasp than rims alone. The development of “power assist” wheels (page 199) makes pushing a manual chair an option for more people, though this chair might not be a final, full-time solution to their mobility needs. Some of these riders use a manual chair at all times, whereas others switch between manual and power chairs, depending on distance and surface and whether they might need to be lifted up stairs, load the chair into a car, and other such criteria. You might use a power chair to go to and from work but use a manual chair at home and at the office. A blend of the two types can be the ideal strategy for your mobility. It is an approach that does not waste your energy or overuse your body.

Yet another solution is a three-or four-wheeled scooter. Scooters are considerably less expensive than power chairs but can give a manual chair user additional mobility for traveling longer distances or climbing steep slopes. They require greater upper body balance, and only certain products can be configured with the specialized pressure-relief seating many riders require. Some users find a scooter preferable as a full-time solution, but, for people unable to walk, this is far less the case.

An option that first appeared in the late 1990s is the power assist chair—in most cases a standard manual chair modified with power assist wheels.

Thanks to advances in computer chips, this design uses small processors and software that read the user’s push on the wheels and sends signals to small motors at each wheel hub to “assist” with a little added power to spare the user from having to provide all of the force of the push. The greatest beneficiaries of this are people with low-level quadriplegia, at risk of overstraining from pushing a standard manual chair but hard pressed to resist getting one for the added flexibility it provides. Power assist is for people who don’t have sufficient strength or balance to do all of the work of pushing an unassisted manual chair on their own.

The system adds a lot of weight to the chair—battery pack, motors, modified wheels with controls—but the weight is more than made up for by the benefits of the power assist. Compared to a power chair, the weight savings is substantial in comparison. The wheels typically have a switch to choose different gears, since you want more power out on the open road compared to the short distances you’ll travel in your home. It is also possible to turn the system off, but then you are pushing a very heavy chair. The wheels can be removed so the chair can be loaded into the trunk of a car— clearly not an option for most power chairs.

The technology is not entirely mature and takes some getting used to. It is not as if you are pushing a manual chair and it’s just easier. Power assisted chairs have a different feel. When you first try it, you might find it lurches on you until you get the feel for how to interact with it. And because the chair is battery-powered, your range is limited by how long the charge lasts—shorter when you are handling more uphill slopes. All of this said, many users get the feel of its unique personality and find this is the perfect option for their needs.

Frank Mobility of Oakdale, Pennsylvania offers the EMotion wheels, and Quickie Designs/Sunrise Medical offers their Xtender power assist option. These systems add approximately $6,000 to the price of the manual chair, in some cases more than the cost of a power chair. Some find it worth the extra expense.

Inventor Dean Kamen has gained a degree of fame for his high-tech design of the iBot wheelchair—which has gotten a lot of exposure in the media for some of the particularly unique abilities it offers, most notably the ability to climb stairs and to elevate and balance on two wheels (Figure 4-1).

Anyone who has gotten good at wheelies knows how secure one can feel once you get the hang of the gentle forward and backward adjustments to the wheels that keep you from falling over. This is what the iBot does when it is in “standing” mode. Gyroscopes and constant monitoring from the onboard computer read your center of gravity and continually adjust, providing for a surprisingly secure feeling knowing you’re in a wheelchair that is balancing on two wheels. The benefits: reaching those higher shelves and getting up to eye-contact height during conversations with a standing person. This technology has been transferred over to the Segue™, the two-wheeled standing scooters that are becoming more commonly visible being used by airport security staff, for example.

There are actually six wheels on an iBot, part of a wheel assembly that rotates as a whole to lift the chair in space. It also is how the chair is able to climb stairs; as the assembly rotates under the seat, the upper set of wheels moves to the step below. Stair climbing requires either that the user be able to hold onto a railing as they do it or have a walking helper who assists behind the chair. The iBot is also able to traverse soft surfaces, including sand.

The price tag is very high, and, at publication, the US government had yet to authorize their purchase under the Medicare program. The Veterans Administration, though, has indeed been buying iBots for qualified users. Not anyone can use it—there is an evaluation you must go through to determine if you have the cognitive and physical ability necessary for safe use of this latest, most-advanced wheelchair technology.

There are a number of decisions that are unique to choosing a manual chair, beginning with narrowing down the choice between the two primary types—rigid or folding. The wheels are also very different between manual and power wheelchairs, not the least because you put your hands on them with a manual chair. That relationship is crucial for how easily and safely you’ll be able to propel your chair—and so how fluid your mobility will be.

It used to be that most manual wheelchairs folded. But a mechanical engineer will tell you that when you push a folding wheelchair, some energy is lost in the flexing of the frame. Less of the force (and effort) of your push translates into forward motion. The loss of energy in a flexible frame led chair designers to come up with the rigid frame chair. According to Doe Cayting of Wheelchairs of Berkeley:

Freed of the mechanism for folding, a rigid chair also has fewer parts and is therefore much lighter and less prone to maintenance problems. With fewer moving components, the frame has more strength. More of the energy of your push translates into motion. The rigid chair design also allows for the angle of the seat frame to be adjustable, impossible with a folding chair because the vertical supports for the chair back are part of the frame structure. The familiar cross-frame structure underneath the seat of the typical wheelchair is not needed with a rigid chair, streamlining its appearance. For those who want to reduce the visual emphasis on their disability and will be pushing greater distances in an average day, the rigid frame design has come to be a de facto standard. Figure 4-2 shows a typical rigid chair.

The front structure that supports the footrest is typically integrated into the frame of the chair, rather than being removable or “swingaway” footrests (although there are some rigid frame products that offer this option). But along with the changes in design fostered by the rigid frame approach, the angle of the footrest has come in closer so that one’s feet do not extend out so far from the body. This user has noted the occasional difficulty of fixed footrests but finds a rigid chair necessary because of its more rugged construction:

However, rigid chairs can be bulky for transporting in a car and do not neatly fold up when they need to be out of the way.

You will want to consider what kind of terrain you will be traveling over. Rigid frames are best for hard, reasonably level surfaces. On uneven terrain, a rigid chair will give you a harder ride. And because the frame does not flex, one or more wheels might not be in contact with the ground on uneven terrain, resulting in a possible degree of loss of control, which can be dangerous.

Rigid frame chairs are so responsive that just minor movements of your body can be enough to adjust direction—a technique riders can use to make fine adjustments as they wheel. Some people find rigid chairs a little oversensitive, but many swear by them and will never go back to a folding design.

There are a few important reasons why some riders still prefer folding chairs. Folding chairs are likely to fit in most vehicles. On uneven surfaces, all four wheels of a folding chair are better able to remain in contact with the surface because of its flexible frame. The flexible frame also absorbs small bumps and vibrations in your ride. Figure 4-3 shows a typical folding chair.

Some riders prefer a folding chair’s ability to fold into a more compact unit important for a variety of reasons that relate specifically to their daily life.

Wheelchair makers have put considerable effort into building folding frame chairs that are also ultralight, as well as improving the structure to keep flexing to a minimum and so not waste as much energy of the push. There have also been attempts at alternative designs that attempt to achieve the best of both worlds—rigid-frame performance in a folding frame. Quickie/Sunrise Medical, Kuschall, and Nissin are companies that offer such products. It remains the holy grail of the wheelchair industry.