Heavy Duty Power Wheelchairs

The powered wheelchair controller and its associated modules and components serve as the command center for use of the wheelchair and its functions. There are two types of commonly used controllers found on wheelchairs today, integral controllers and modular controllers. Integral controllers contain all of the necessary components in one housing with the joystick. Modular controllers have separate components for the various functions and wheelchair controlling elements. Both will include a joystick or some type of user interface as part of the system.

Some wheelchair models, especially the less sophisticated or less costly ones, allow no choice of controllers and come standard with an integral controller. The integral controller is used for basic mobility applications when no additional or special control features are anticipated. A user who can be expected to have little or no change in functional status over a long period of time, and whose powered wheelchair requires no special or sophisticated features, would be a good candidate for this type of control.

The technically higher end wheelchairs will sometimes offer a wide array of controller components and configurations. This is done to allow and accommodate the use of different types of controls and interfaces. It allows for mixing and matching of components to accommodate such function enhancers as sip and puff controls, specialty switches, powered seating systems, and even external devices such as environmental control units or communication devices. For example, the use of a sip and puff, head array system, or chin control, would be difficult or impossible to interface with most integral controller systems since these systems can not accommodate them. The electronics do not allow for interfacing or communicating with these devices.With a modular system the item can be added to the wheelchair as long as the appropriate interface module is also added or is already onboard.

The primary and the most important trade off on these systems is flexibility. If flexibility in functional control of the wheelchair features is required or anticipated then the modular system is the way to go. If not, the integral system should work well.

This is turning into a “Who's on second?” thing, therefore it's time for some pictures and some ups and downs.

• Integral is less costly.
• Integral is simpler and easier to deal with.
• Modular is more flexible and allows greater latitude in choosing the types of interfaces and controls.
• Devices such as environmental control units and communication systems can be operated through a modular system.
• Various types of driving controls such as head array, sip & puff, touch pad, and chin controls can be added with a modular system.
• With a modular system, if user function or ability changes the existing system can be modified or added to without replacing the entire wheelchair.
  
  

• Integral is less flexible and cannot easily be expanded on.
• Integral control is much larger.
• Integral is to large to center or offset mount on the wheelchair.
• Modular is more expensive.
• Modular requires experience or training to setup when adding features.
• Modular systems may require components and interfaces from multiple aftermarket sources to achieve the desired result.
• Components for a modular system must be compatible with existing electronics.
• Many compatibility issues may arise when setting up a complex integrated system.
• Modular controllers increase the wheelchairs level of complexity.

Lateral trunk supports are also known as laterals, lateral supports, lateral thoracic supports, and trunk stabilizers. They are rectangular or square shaped devices that mount to the back posts of the wheelchair and rest against the user's trunk. Most often they are used in pairs, one on each side of the trunk.

Laterals come in a number of different sizes and padding densities. Size and shape will vary depending on manufacturer and style. The most common styles are planar (flat) or contoured (shaped). The amount of contouring may also vary between styles and manufacturers. Many models can be ordered with hardware that allows the lateral to swing away from the user and out of the way. This makes getting in and out of the chair much easier. Laterals are available from the wheelchair manufacturer or can be purchased from a number of aftermarket sources.

These positioning accessories are most often used to increase the user's trunk stability and balance. They can also serve as a tactile reminder. When the user comes in contact with the device they know that they are out of position and can adjust their position or request assistance. Laterals are sometimes used in an effort to control spinal scoliosis ("S" curve of the spine). This tactic may work in those cases were the scoliosis is flexible and can easily be reduced. In cases where the scoliosis is rigid, laterals may cause discomfort and tissue damage (wounds). This is especially true if the lateral is placed on the apex (high point) of the spinal curvature. That brings us nicely to the issue of placement.

If the trunk can be placed in an upright neutral sitting position, but the user can not maintain this position, then the laterals can be placed opposite each other on each side of the trunk. This will add the needed external support to hold the user in position. Many users and professionals think that the laterals have to be placed exactly opposite each other on the trunk. This is not true, and in certain cases may result in poor outcomes and in discomfort to the user. In those cases where you are dealing with a spinal curvature you need to consider uneven or oblique placement of the laterals. One lateral should be placed just under the apex of the spinal curve. The second lateral should be placed on the opposite side of the trunk and above the opposing one. This will set up the proper dynamics for reducing the curve (if flexible) and supporting the trunk.

In order to work well these devices must make contact with the trunk. If they do not make contact with the user there will be no support. If they are too tight, the user may have a problem with breathing. If they are placed too low, support is lost and the trunk may "lean" over the laterals. If placed too high they may impinge on the axilla (armpit) and cause damage to the brachial plexus, irritate the surrounding skin, and restrict shoulder and arm movement.

• Aids in trunk support and stability.
• Improves balance and posture.
• Helps maintain the user in a functional position.
• Prevents further postural decay.
• Diminishes the need for repetitive repositioning of the user during the day.
• Improves appearance.
  
  

• If placed too low they are ineffective.
• If placed too high they may irritate axilla, brachial plexus, surrounding tissue, and limit shoulder and arm movement.
• May be difficult to mount to backrest in proper location.
• When the pad is under pressure the swing-away release may get stubborn.
• Even contact of the entire pad against the body is difficult to realize since there are no adjustments for angling the pad in or out.
• If the user changes position the laterals will most likely no longer be aligned correctly.
• They add another layer of complexity to the entire unit.

A mounting arm for the joystick with an articulating (hinged) joint that makes it possible to swing the control away and back. Most models have a tension mechanism for locking the arm into the forward position. These items can be obtained from the wheelchair manufacturer or a number of aftermarket sources. Depending on the source there are slight differences in design. These devices are primarily used to allow powered wheelchair users to get closer to and under tables, desks, etc.

• Makes it possible to move the joystick out of the way to get closer to tables, desks, and workstations.

• The position locking mechanism or the moving parts may loosen after time making the joystick box wobbly and difficult to lock and hold in place.
• User may not be able to manage the device independently.
• Most often this device is an optional upgrade to the wheelchair and will add extra expense.