Clinically Speaking

Choosing the Correct Specialty Control for Your Client

• By Jay Doherty
• Oct 01, 2013

When it comes to power wheelchair evaluations, choosing the correct specialty control for those in need can require notable attention by a seating clinic’s team. This process is made most effective with several strategies.

Firstly, the team needs to look at the part of the anatomy with which the individual will have the most consistent access for independent control over the power wheelchair. Put simply, where does the individual have the highest, most consistent function throughout the day? In some instances, the individual may have two consistent locations for access on his or her body that he or she can share throughout the day. However, the drawback to this scenario is that two different types of input devices/specialty controls may be necessary for independent control all day.

Secondly, the team should assess other factors that dictate proper application, such as cognition and tone. For instance, it’s important to note whether a client can understand or remember the steps involved with using the specialty control, and if he or she can release the specialty control in an emergency situation so the wheelchair stops adequately.

A Systematic Checklist

When considering a specialty control for the individual’s specific needs, I recommend taking into account the input methods in the following order, but you may use your own best judgment:

• Proportional joysticks
• Other proportional devices (chin controls, proportional head or proportional foot control, etc.)
• Switches
• Head arrays
• Head array/sip-and-puff combination
• Sip-and-puff
• Single-switch scanning

The noted order is very important since a proportional control will provide the consumer with the most control over the power wheelchair in all directions of travel. Common proportional controls are a standard joystick, mini proportional or minimal-throw proportional joysticks, proportional head arrays, touch pads, Magitek and a variety of differently configured proportional joysticks. A proportional input device can be placed virtually anywhere as long as the consumer has the control to access at least three directions of movement — forward/reverse, left, right — or ideally, four for full access.

Before moving beyond a proportional control, try changing the device’s programming. Many power wheelchair manufacturers allow the programming of a proportional joystick via the controller. Some of the programming features to look at are tremor suppression, three-direction proportional control, throw, center dead band, and reassign direction. These different features may solve control issues for the individual.

Making a Switch

After ruling out proportional controls, the team should look at nonproportional or switched-type devices. It doesn’t matter what type of switch is being utilized, as all switches work very similarly when it comes to electronics.

A switch is either activated or inactive. When a switch is activated, the wheelchair will drive the speed the drive profile is programmed. There will be four directions of control — forward, reverse, left and right — with a switch assigned to each direction. Veering directions often can be achieved by activating two switches at the same time, resulting in the power wheelchair veering forward to the right.

The benefit of switches is that they can often be placed in locations that a proportional type device will not easily fit. This provides an advantage for individuals who have an exact location with little space for that particular access point. Some examples of switched inputs are a head array, mechanical or electric switches (single and multiple), and sip-and-puff. All of these are switched input devices because the system is either on or off when the switch is activated.

When considering switched specialty controls, we need to look at what type of switch best meets the individual’s needs. Aspects to consider with switches are the size, the pressure required to activate the switch, and whether it is a mechanical switch or a powered switch, to name a few. (Keep in mind that some people need the feedback that a mechanical switch provides. When you press a mechanical switch, you feel the switch press and often can hear it click.)

For some individuals, this type of feedback is very important. The only feedback that a person typically gets from an electric switch is the wheelchair will drive in the direction of the switch he or she activated. Some individuals may fatigue quickly with powered switches. You may be thinking that doesn’t make sense, but some people will continually press hard on an electric type of switch because they don’t feel the switch depress — and that causes fatigue. If you have a person who is fatiguing while driving with an electric switch, check to see how much force he or she is using on the switch.

Once you find the best input device and location, the next step in the process is finding a way to mount the input device securely. This requires a skilled technician. After the input device is mounted, have the consumer drive the wheelchair, and ensure that he or she can use the input device while using the power seat options for repositioning, pressure relief, transfers, etc. Use of power seating can often change access to input device. This is a part of the evaluation and fitting process too often accidentally overlooked by teams. If this step is forgotten, the consumer may get home and lose contact with the input device when repositioning.

As anyone who works with power mobility and very high-end input devices knows, the evaluation process is significant, but the result is what we all strive for: a functional, independent consumer.

This article originally appeared in the October 2013 issue of Mobility Management.