Assessing Student's Needs for Assistive Technology (ASNAT)

Chapter 6 – Assistive Technology for Recreation …
Selecting Switches
Switches are frequently used to improve access to a device such as a radio, tape player, toy or computer.
They are commonly used during the training process to teach concepts such as cause and effect. In
selecting a switch, the first question to ask is, “What do you want a switch to do?” Switches come in a
variety of shapes, textures, sizes and activation modes. However, virtually any item can be turned into a
switch by using the Taction Pad (Adaptivation). Taction Pads are clear, adhesive backed, touch
sensitive patches that can be adhered to any surface or object.
Take time to think about what the switch will do. Activities that involve water or cooking may not work
well with a light sensitive switch that can get gummed up with food. A switch that is to be activated by
hand or foot may need to be bigger than one activated by fingertip. So the end use and location are
significant in the choice of a switch.
Consider:
♦ What is the most consistent movement the child makes and controls?
♦ What part of the body will be used to activate the switch?
♦ Is the switch appropriately durable for this? Is it the right size?
♦ Is the child capable of producing the amount of pressure required by the switch?
♦ Will use of the switch fatigue the child? If so, how long can it be used before fatigue is a factor?
♦ Will continued use cause contractures? If so, can the switch location be varied during the day?
♦ Does the use of the switch require an undesirable body position or movement?
Most switches are activated by touching them in some way. The most common is a round pressure
switch such as the Jelly Bean ® switch (Ablenet), but there are many other styles available. Please note
the resources listed at the end of this article, if you are not familiar with common sources of switches
and adapted toys. If a child cannot directly activate a switch, can they move their body in a way that a
movement based switch or a remote type switch could be activated? Movement based switches react as
their name implies, to a movement the child makes. Common ones are the mercury switch and a light
sensitive switch. Moving the mercury from one side to the other activates the mercury switch. A child
might wear the switch on his/her head and tilt the head to the side to activate the switch. It could also be
strapped on the hand and then turning the hand over would activate the switch.
A light sensitive switch responds to a movement over the light sensor blocking the light, which then
triggers the switch. There are also switches that work on the principle of a remote control. Some will
interface with a computer, (e.g., the Tracker 2000). Using a head controlled sensor to point at the screen
the computer is equipped with a receiver that interprets where the mouse is on the screen activating the
area. Other switches work with an interface to control various electronic equipment in the environment.
Another consideration for switch use is the fatigue factor. Does this child tire easily? Fatigue can play a
crucial role in how long a child can use a switch in the same position. Frequently changing the position
of the child and/or the switch placement is often a useful way to prolong the child’s ability to use
assistive technology. Careful observation and record keeping can help identify a child’s preferences for
position and switch location. The preferred position can then be saved for tasks with a high cognitive
demand. Utilize the more challenging access mode(s) or position(s) for lower cognitive load tasks and
preferred
Assessing Students’ Needs for Assistive Technology (2004) 160