Control Systems: Different Ways of Driving

by Kathy Wechsler on September 1, 2004 - 2:49pm

If the standard joystick is no longer an option for driving your power wheelchair, don't be discouraged. No matter what type of disability you have, there's a wheelchair control system that can be configured to help you operate your chair.

Finding the right wheelchair control system takes the specialized knowledge that only a team of experts can offer, said Mike Mansfield, a certified rehabilitation technology supplier (CRTS) and president of Rehab Specialists in San Francisco.

Just as in buying a new wheelchair or fitting your existing one with a new back or cushion, choosing a new control system requires the help of a physician, a physical therapist (PT) or occupational therapist (OT), and a reliable medical equipment supplier.

Ideally, the supplier should be certified through either the Assistive Technology and Rehabilitation Engineering Society of North America or the National Registry of Rehabilitation Technology Suppliers. (See "Control System Resources.")

Tracie Cross of Adorno Mobility in Houston recommends contacting your local MDA office for a list of reputable suppliers who are familiar with muscular dystrophy.

What's out there?

Almost all wheelchair manufacturers allow you to upgrade your chairs control system, said Mansfield, who's worked with people served at Stanford University's MDA clinic and the Forbes Norris MDA/ALS Research Center.

Most power chairs by Permobil, Quickie, Invacare, 21st Century Scientific and Pride come with standard electronics. But they also include the option to upgrade the control box's electronics to suit your needs.

That means you can continue using your own chair and choose a driving system from a range of driving arrays. Whether you select a system controlled by head movement, breath, body heat or something else depends on which part of your body has the most strength or control.

Armed with knowledge of the options on the market, you're ready to talk to your PT or OT and equipment provider about getting evaluated for a wheelchair control system.

Using your head

The term head array describes a device that lets you drive your chair using only your head. These devices require some neck strength to operate the switches and sensors placed in the padding of the chairs headrest. Adaptive Switch Laboratories (ASL), Creative Rehab Associates and Switch-It offer head array devices.

Overhead view of Jon Whitmer's head array device
Jon Whitmer drives his Permobil Chairman 2K with an ASL head array device. The control system is mounted on the chair. (Whitmer uses noninvasive ventilation during the day.)
A member of Magitek's team adjusts Roy Lemert's control system
Steve Lautzenhiser, a member of the Magitek team, makes final adjustments on Roy Lemert's Magitek Drive Control System. Seat tilt and recline actuators on Lemert's Invacare power chair are also controlled by the Magitek system.
TaDarius Moore
TaDarius Moore drives his power chair with small color-coded electric buttons from Tash.
Alan Houghton
Alan Houghton uses a minijoystick with a Haims harness and a head switch that came with his Permobil wheelchair.

Jon Whitmer of Billings, Mont., has a head array device by ASL, with three main switches in his headrest that activate the control box. The switch in back tells the chair to go forward or reverse, and the two side switches control left and right turns.

Whitmer, 33, activates a light beam switch with his chin or tongue to change modes (such as going from drive to tilt/recline) or put the chair into standby.

Whitmer, who has Duchenne MD, has used a control system for nine years. He recently purchased a Permobil chair with a new ASL device that lets him activate switches with his head to operate the chair, control the leg rests, elevate the seat, as well as tilt and recline.

"I'd recommend ASL. It seems to me that it's more user-friendly," Whitmer said. He said some other devices were covered with fabric and harder to push, but "with the ASL head array, its right there, you don't have to mash anything. You just have to get close."

Decisions, decisions

Coming in all shapes and sizes, switches can be attached to any part of your wheelchair so you can use your foot, toe, knee, trunk or shoulder to send signals to the control box and drive your chair.

Or, sensors can be mounted on your eyeglasses, an earpiece or a special headband, letting you drive by tilting your head. You can design a custom control device with the help of ASL, Magitek, Stealth Products or Whitmyer Biomechanix.

A Magitek system acts as a "joystick in space," said company co-founder Steve Lautzenhiser. It works by placing miniature tilt sensors on your head, hand, finger, foot or elsewhere. The sensors can be moved, adjusted, or divided and placed in other locations.

Lautzenhiser says this system allows precise control of the wheelchair, with more adaptability than other fixed-headrest based systems offer. Activating the tilt sensors does require some physical movement.

"Our systems can accommodate a diverse set of applications for solving difficult mobility challenges because the migratory tilt sensors are fully proportional and very natural to use," Lautzenhiser said.

Tash and Stealth Products also offer a variety of adaptable buttons and switches.

TaDarius Moore of Nashville, Tenn., has spinal muscular atrophy and maneuvers his wheelchair using small color-coded electric buttons mounted on a tray in front of him. TaDarius, 9, has had his Jellybean Drive System from Tash for four years.

He says he likes this system because it allows him to get around.

The chin is in

Chin controls cover a large range of products. You can get a cup-shaped joystick handle that attaches to your chair just below your chin or a minijoystick that mounts midline.

A harness system or brace can hold the joystick where you need it. The Haims Harness System, made by Permobil, can also accommodate a joystick to be used with the lips or tongue.

If you can only perform minimal movements, your best bet may be a minijoystick. This small and compact joystick can be placed anywhere on your chair for maximum accessibility the armrest, legrest or anywhere else you have movement.

Manufactured by HMC International and offered by ASL, Pride, Permobil or Invacare, the minijoystick makes it easy to maneuver your chair using your finger, hand, chin or tongue.

Alan Houghton of New York has Lou Gehrig's disease, and he uses his chin to manipulate a minijoystick attached to a brace around his neck. With this device, he can drive and also control his chairs other functions such as adjusting his legrests. A button attached to the right side of his headrest allows him to change modes.

"I like that [this system] doesn't take a lot of energy, but allows for a lot of flexibility," said Houghton, 57, a cancer researcher and oncologist at Memorial Sloan-Kettering Cancer Center. "It makes it so that I can get around and work all day."

Hot air and other cool stuff

If your lungs are strong and aren't easily fatigued, you can go with a sip-and-puff device. By taking sips of air or blowing into a strawlike tube, you tell the wheelchair what to do. Switch-It, Origin Instruments and Therafin offer sip-and-puff systems.

New Abilities Systems makes a tongue-touch keypad that fits in the roof of your mouth.

Stealth Products, ASL and Switch-It make proximity switches, which are triggered by your body heat. You don't even have to touch the switch to activate one-step commands such as on/off.

For those with the most limited movement, fiber optics from ASL and Switch-It may be the best choice. These tiny fibers are extremely sensitive to the lightest touch.

Finger-touch keypads from PG Drives Technology and Switch-It also allow driving with the movement of your finger.

You can even get a joystick mounted on the back of your chair for a caregiver to operate.

"The sky's the limit," said Cross of Adorno Mobility about the current options.

KEMPF manufactures a voice-operated wheelchair control system. With the KATALAVOX, you can also use a throat microphone or a headrest microphone to pick up your vocal vibrations. This is a new product that's still being perfected, Mansfield said.

The chin mount minijoystick from ASL can be placed right where you need it.
Using the Gatlin tray with fiber optics by ASL, you can drive your wheelchair with a finger.

Future technology promises that you can operate your chair with your thoughts by wearing a skullcap covered by electrodes to monitor the electrical activity of your brain.

Planning and paying

As you consider your choices for a wheelchair control system, it's important to keep the lines of communication open, said Cross, an assistive technology provider (ATP) with nine years experience as a PT.

It's also a good idea to plan ahead for future needs, especially if your disease is progressive. Getting the equipment before you absolutely need it can keep you from being stuck with no means of mobility.

Specialty control systems aren't cheap. They can range in price from $1,500 to $8,000 for an extremely complicated system.

If an alternative driving device is deemed medically necessary, your health insurance should cover it. Medicare or Medicaid may help pay for these products if they're deemed medically necessary. If you're adding a control system to your existing chair, MDA will pay up to $500 every year for repairs or modifications.

Control System Resources

Adaptive Switch Laboratories
(800) 626-8698
www.asl-inc.com

Creative Rehab Associates
(830) 693-6030

Dynamic Controls
(440) 979-0657
www.dynamic-controls.co.nz

HMC International
www.hmc-products.com

KEMPF-KATALAVOX
(800) 255-6174
www.katalavox.com

Magitek
(800) 347-9928
www.magitek.com

New Abilities Systems
(800) 829-8889
www.newabilities.com

Origin Instruments
(972) 606-8740
www.orin.com

PG Drives Technology
(714) 712-7911
www.pgdt.com

Stealth Products
(800) 965-9229
www.stealthproducts.com

Switch-It
(800) 376-9888
www.switchit-inc.com

Tash
(800) 463-5685
www.tashinc.com

Therafin
(800) 843-7234
www.therafin.com

Whitmyer Biomechanix
(877) 944-8246
www.whitbio.com

Invacare
www.invacare.com

Quickie Wheelchairs
www.quickie-wheelchairs.com

Permobil
www.Permobilusa.com

Pride
www.pridemobility.com

Sunrise Medical
www.sunrisemedical.com

21st Century Scientific
www.21stcenturyscientific.com

Assistive Technology and Rehabilitation Engineering Society of North America (RESNA)
www.resna.org

National Registry of Rehabilitation Technology Suppliers (NRRTS)
www.nrrts.org

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