People with disabilities who find it hard to walk or use a manual wheelchair may benefit from a powered wheelchair to help them get around at home and in the community.
There are many ways to control a powered wheelchair. The most commonly seen interface is the conventional joystick. However users who are unable to use the conventional joystick due to certain physical limitations can explore different types of controllers. Here, our occupational therapist Alan Ong shows us some of these alternatives.
Different Types of Joystick Handles
This is the most commonly seen joystick. It comes as a default joystick for most of the powered wheelchairs.
The large soft ball is easier for grasp with the entire palm and allows release to make the wheelchair stop. It is an option for users who have poor finger control.
The T handle may be appropriate for users who use more gross motor movements from the elbow and shoulder to control the joystick.
The stick handle is longer and thicker and is suitable for users with reduced strength of the fingers or hands.
This U-shaped handle may be beneficial for users who use more gross motor movements from the elbow and shoulder to control the joystick. It provides more support for the hand compared to the T handle.
This handle provides a larger surface area for users with poor grasp and motor control to operate the joystick effectively.
The Large Ball handle makes grasp easier for users who find it hard to hold and use the conventional standard cone-shaped joystick.
Alternative Drive Controls
The user’s finger can function as a joystick to control the wheelchair. The wheelchair can be controlled with minimum pressure of the finger. This control may be beneficial for users with contractures or extremely limited strength and finger movement.
The user’s forearm or hand will act as a joystick on this durable, flat tablet. The tablet control may be beneficial for users who lack fine movement of the fingers and have low strength.
Users can control the wheelchair using foot movements. This may be beneficial for users who use the foot as the superior control site.
The chin control works similarly to the conventional joystick in that the user pushes the joystick in the direction they wish to go and control the speed by how much they push. The joystick can be changed to a small knob or chin cup. The chin control may be beneficial for users who are unable to use their upper and lower limbs to drive the wheelchair.
There are many different types of head control interfaces. One requires the user to have contact with the headrest. Moving forward is achieved by constant contact of the head backwards with the headrest and turning the wheelchair is achieved by angular head motion to the left and right. An integrated mode switch toggles between forward and reverse direction and provides access to non-driving operations. The head control may be beneficial for users who are unable to use their upper and lower limbs to drive the wheelchair.
Wafer Board Control
The switch of wafer board controls causes the wheelchair to move at a pre-programmed speed in one direction. There are five switches in all with four switches for direction and one for mode menu. This may be beneficial for users who find it hard to control the deflecting joystick where the more the user pushes the joystick, the faster the wheelchair moves.
Proximity Switches Control
For proximity switches, they do not need pressure to be activated. A hand or finger placed above the sensor will cause movement of the wheelchair in the appropriate direction. This may be beneficial for users who cannot sustain pressure on even the lightest touch switches.
Scanner Drive Control
There is a display with five blinking lights (four for directions and one for mode) on the scanner drive control. The lights will scan through the selections and the user will depress the switch when the command they want is lit up. This may be beneficial for users who find it hard to control the deflecting joystick where the more the user pushes the joystick, the faster the wheelchair moves. It also helps those who find it difficult to use multiple switches like the wafer board.
Sip-and-puff uses slight sucking and soft blowing action through a tube to drive the powered wheelchair. The system can distinguish between a sip and a puff and also know the strength of the sip and puff. Hard and soft sip, hard and soft puff are different commands. This may be beneficial for users who have no or poor control of the upper limbs and lower limbs and are unable to use conventional joystick, switches or head/chin controls to drive a power wheelchair.
A lot of the control interfaces that are available today make it possible for users with only one or two movements to operate a powered wheelchair. However, cognitive, perceptual and behavioural impairment may prevent certain individuals from using the powered wheelchair even if they have the necessary movements to operate the powered wheelchair. The person using the powered wheelchair needs to be able to operate it safely. Thus it is recommended that users undergo an assessment, evaluation and training by an occupational therapist or assistive technology specialist before purchasing the powered wheelchair.
Those interested may contact our Specialised Assistive Technology Centre at 6473 0446 for more information regarding assessment for suitable powered mobility equipment (powered wheelchair and scooter) and training in the use of the equipment.
Content and images sources
Assistivetech.net. (n.d.). Switches Overview – ATWiki. Retrieved November 28, 2014, from assistivetech.net
Cook, A. M., & Hussey, S. M. (2002). Assistive Technologies: Principles and Practice . St. Louis, Missouri: Mosby, Inc.
McCaskill, P. (n.d.). Retrieved November 28, 2014
Ottobock. (2014). Ottobock – Input Devices. Retrieved November 28, 2014
Permobil. (2014). Permobil. Retrieved November 24, 2014
Permobil USA. (2014). Power Wheelchair Accessories. Retrieved November 28, 2014
Stewart, D. (2014). Power Wheelchair Drive Controls. Retrieved November 24, 2014