Recently, my colleague, Ron Claughton, Account Manager with Sunrise Medical, and I presented on specialty controls at the Canadian Seating and Mobility Conference (CSMC) in Toronto. Not only did we discuss various specialty control options, but we also demonstrated the use of specialty controls both live and through videos. Therapists and vendors were given the opportunity to drive power wheelchairs using alternate input devices. Hands on is a great way to learn, but of course, not everyone is able to attend CSMC, so I thought I would share some information on specialty controls in this month’s blog article.
While a joystick is the most commonly used input device to operate a power wheelchair, not everyone has the physical ability to operate a wheelchair using a joystick and for these people specialty controls, or alternative input devices, are required. Just remember to ensure that it is not the programming of the power wheelchair that is limiting the person’s ability to drive a power wheelchair with a standard joystick gimble! (For more on the common adjustments that can be made to the programming of a power wheelchair, please refer to my article on Power Programming Basics at http://www.clinical-corner.com/2012/06/power-programming-basics/). Also consider the handle on the joystick gimble. Would a ball, knob or a goal-post handle, rather than a typical stick handle, enable the person to drive a power wheelchair safely and effectively? In addition, consider the position of the joystick. Joysticks can be mounted to the right, to the left, or anywhere in between! Would a midline mount of a standard joystick enable independent power mobility? Of course, changing the orientation of the joystick from a standard orientation to a mid-line mount may require programming changes for the active orientation of the joystick.
Proportional Input Devices
A standard joystick is an example of a proportional input device. This means that the amount of deflection on the joystick gimble will correspond with a given rate of movement of the wheelchair, similar to how a gas pedal on a car works. Thus, the further the joystick is pushed out of the neutral position in any direction, the faster the wheelchair will go. Alternative joysticks, which require very little force or deflection for activation, are available. These include the MicroPilot and Touch Drive by Switch-It, Inc. and the Proportional Mini and Micro Mini Joysticks by ASL, Inc.
Non-proportional Input Devices
A switch is an example of a non-proportional drive control. This means that the switch is either “on” or “off”, similar to how a light switch works. Each switch is pre-programmed for one direction and speed. Thus, activating the switch activates the movement of the wheelchair for a set speed and direction. Other examples of non-proportional drive controls include sip and puff and head array with switch control. (A proportional head control also is available.)
Switches can be either mechanical or electronic. Mechanical switches require a depression of the switch to activate. There are numerous choices available in mechanical switches, ranging in size and amount of force required to operate the switch. In comparison, electronic switches, such as Fibre Optic Switches (Switch-It, Inc), do not require direct touch to operate. Depending upon the programming, the fibre optic switch may be activated when an object either is detected within the adjusted range or moves from the adjusted range.
Assessment and Trial
Deciding upon what is the most ideal input device for a power wheelchair user starts with the assessment of the individual. Part of that assessment will include evaluation of the access point, or the part of the body that will be used to control the wheelchair. The access point is the point on the body for which the person can move reliably in two directions. Potential access points include the head, cheek, temporal area (with caution), mouth, chin, finger, thumb, elbow, knee, foot, and toes. Whether a proportional or non-proportional input device is chosen for an individual depends on the type with which the person has the most success. Training with, and trial of, equipment is the key to ensuring proper prescription of a specialty control. What is also important is the postural stability of the individual in the wheelchair to ensure consistent access to the specialty control. A person driving a wheelchair with a specialty control must always be able to reach the input device to operate the power wheelchair.
I have mentioned in a previous article, and I believe it bears repeating, that the use of specialty controls requires expandable electronics on the power wheelchair. If the use of specialty controls may be required for a person during the life of the power wheelchair, expandable electronics should be selected at the time of the initial wheelchair prescription to allow for the anticipated use of a specialty control. (For more information on power wheelchair electronics, please refer to my article on De-mystifying Power Wheelchairs – Selecting Electronics that can be found at http://www.clinical-corner.com/tag/power-wheelchair-electronics/.)
As therapists, we can facilitate independent mobility for individuals through thoughtful prescription of a specialty control input device. As my education counterparts at Sunrise Training and Education Programs (STEPS) in the U.S. say, Mobility is POWERful!
As always, please provide your comments, questions and suggestions regarding Clinical Corner on my blog at www.clinical-corner.com. I look forward to hearing from you!
Sheilagh Sherman, OT Reg. (Ont.)
Sunrise Medical Canada
Note: The content of this article is not meant to be prescriptive; rather, it is meant as a general resource for clinicians to then use clinical reasoning skills to determine optimal seating and mobility solutions for individual clients. Sheilagh is unable to answer questions from members of the general public. Members of the general public are directed to their own therapists or other health care professionals to ask questions regarding seating and mobility needs.
Arva, J., Furumasu, J., Harris, M., Kermoian, R., Lange, M., McCarthy, E., Pinkerton, H., Plummer, T., Roos, J., & Rosen, L. (2009) RESNA Position on the Application of Power Wheelchairs for Pediatric Users. Assistive Technology. 21, 218-226
Cook, A., Polgar, J. (2007). Cook and Hussey’s Assistive Technologies: Principles and Practice 3rd ed. Philadelphia: Mosby
Cook, A., Plogar, J. (2012) Essentials for Assistive Technologies. Philadelphia: Mosby.
Cooper, R. (1998). Wheelchair Selection and Configuration. New York: Demos Medical Publishing.
Massengale, S., Folden, D., McConnell, P., Stratton, L., & Whitehead, V. (2005) Effect of Visual Perception, Visual Function, Cognition, and Personality on Power Wheelchair Use in Adults. Assistive Technology, 17, 108-121.