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An independent assessment and engineering service for persons with a disability who require Special Controls
in order to be able to access powered wheelchair mobility or other Assistive Technology.

Assessment methods    


I have been working in the field of Special Controls for powered chair users since 1993, and I am pleased to be able to offer you the following services:

Special Controls systems can be broadly categorized into five sub-divisions. As detailed below they mirror the general sequence of events taken during an assessment. They start with the easiest to use systems, i.e. simple joysticks, and progress through to the more limited systems such as the scanning controllers. Typical clinical scenarios are included but they are only for the loosest of guidance.

1) Off Axis mounted remote Joysticks.

These are useful where the client has some limb function but good hand/foot control. A number of different Joystick knobs are available, as is an adapter for fitting P+G joystick knobs onto CDL type joysticks.

2) Simple multiple switches, e.g. the SMARTIE box.

These may be useful where the client has good arm control but has little control of the hands. The latest version of the SMARTIE BOX is suitable for use outdoors.

3) Custom/multiple switches to clients individual requirements.

Useful for clients with poor hand/arm control. Switches may be distributed about the chair or the client in an attempt to improve the level of control the client has.

4) Scanning type wheelchair controllers and switch systems

For clients with little or no control of the limbs. In the latter case head switches or Sip/Puff systems can be tried. Scanning wheelchair control systems also lend themselves to interfacing to environmental controls or other switch activated devices.

5) Extremely limited mobility systems.

This sort of system is used for young persons with severe learning difficulties and/or physical disability. The system may only provide one or two directions and have switch filtering on the inputs. Special Controls would not ordinarily be supplied to a client who could not grasp the concept of their own mobility within a closed environment. However, recent advances in technology include collision avoidance and track following systems which can be very usefull where a client is learning slowly, or has defective vision.

Important Principals for Successful Special Controls Assessments


There are three important principals to a successful special controls assessment for the more severely disabled client, these are:-

1) Disregard custom and practice.

2) Bring the control device to the client, not the other way round.

3) Observation.

Of the three the most important is OBSERVATION !

a) Observation of the client, in particular those parts of the anatomy that seem to be under conscious control. This will tell you what sort of activation devices you can use, the direction they can be used in and where to place them.

b) When controls are being tried, observation for the appropriate activation and release responses in terms of directional control and object avoidance. The merest hint of understanding of the requirements for mobility, even if the client is presently unable to achieve effective activation at the moment suggests that improvement will take place.

c) Observation of the mechanical set-up of any existing wheelchair provision. It is so often the case that the place you want to put something already has something there or needs to be removed regularly for access to the client or other systems. In particular check that you can still get to any charging socket etc.


Posture

For effective powered mobility the client should be in the most relaxed position possible. This is sometimes contrary to the requirements of some of the Physio's and OT's who may be looking for a more upright and functional position. Either a compromise should be reached, or provision made for both types of posture within the seating.


Optimum joystick position

I have often found that the best position for a remote joystick is with the palm just above the knee. Unfortunately this is not always possible to achieve. Whichever position is chosen, confirm that the client has sufficient strength to operate the joystick fully in all directions. If a client has a particular bias to one direction, it can sometimes be useful to angle the joystick housing so that the clients easiest movement is in line with Forwards on the joystick.


Programming

The programming of the control box can make a vast difference to the success of the assessment and the ultimate level of control achieved by the user. This is particularly so when the client is using switches to control the chair. Again, observation is the key. If you observe that the chair is tending to "Kangaroo" a little, generating a startle reflex in the client, or just making it difficult for the client to control the chair effectively, then the acceleration needs backing of for that direction. This seems to be less of a problem where deceleration is concerned.


Feedback

For a client who is very new to switch controlled mobility it is sometimes helpful to have the speed set very low, but the acceleration turned up full. This generates immediate feedback that something has happened as a result of pressing the switch, even if they are startled by it in the first instance. They usually become used to it quite quickly. Once the client has become a little more proficient the speed can be increased and the acceleration decreased to more appropriate levels.

Helpline

If you find yourself a bit stuck during an assessment out in the field, you can always try giving the service a ring. We can't offer any guarantees but we will try and help as much as possible.

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