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Children with severe physical disabilities or profound and multiple learning difficulties find it very difficult to control their environment. They are denied many of the early learning and interactive experiences other children have. In order to provide activities that they can control, it has become common to use simple, battery operated toys and other devices which can be adapted for switch use. In a similar way mains operated equipment can used. Using these devices a simple, single switch can be used to provide control over equipment that the user would otherwise find impossible to operate for themselves.
Toys are adapted by using adaptor leads, which are placed
inside the battery compartment of the toy. These interrupt the current flowing
from the battery to the toy. Using the toy adaptor the toy will only operate
when the switch is pressed down. This will limit the range of activities for
the many users who can only make brief contact with the switch as they wouldn't
receive a sufficient reward for their actions.
In order to provide a greater range of activities, timer units can be connected between
the switch and the toy. These devices allow a greatly extended range of
activities to be carried out with toys.
In the same way, a mains unit can be placed between a mains appliance, such as a food mixer, and the mains socket. When a switch is connected to the control unit the mixer or other device will operate when the switch is pressed.
Choosing Battery Devices
Many simple battery operated devices can be used with switches.
All that is required is a way to place the battery adaptor lead inside the
battery compartment and then connect the switch.
When choosing devices make sure that the equipment chosen is normally operated by a basic on/off switch - more complex or radio controlled devices cannot always be readily adapted. Other equipment, such as simple, battery operated tape recorders or transistor radios are easy to adapt.
Some children find it relatively easy to understand the cause and effect relationship between their holding the switch and the toy operating, Others will require a longer period of time and a lot of encouragement to enable them to develop the necessary physical and kinetic skills to operate the toy.
It is important at this early stage of switch operation to carefully consider the type of switch skills that the child will need to develop for future use. When used without a timer device, toys such as tape recorders or cars will operate only as long as the switch is held down. This may not always be desirable as the skill that is required for future switch use generally involves being able to press and release the switch at will.
A timer unit will activate the device for a pre-set period of time with a brief press of the switch. At the end of the pre-set amount of time the timer turns the device off and the child has to reactivate it by pressing the switch again. This encourages the understanding that brief presses are needed to make something happen.
Battery timers provide a range of activities allowing toys to be con trolled in a variety of ways so the child can take part in different activities. For example, the child can control a story on tape for the rest of the class, or play music for a game of musical statues.
Mains Control Unit
Mains control units such as the Powerlink, allow switches to be used to control electrical devices, providing additional experiences.
For example, a child can take part in a cookery session by using a switch to
turn on and off a food mixer: lights and fans can be connected giving more dramatic
and appropriate rewards for older people. By using 'real' equipment, children
feel that the switch operation is more important
Developing Switch Skills on a Computer
For
children with physical disabilities, or profound and multiple learning difficulties, using
switches on a computer will be an essential way for them to interact and
control their environment. When used with appropriate software, switches can control
much of what happens on the computer screen, ranging from simple cause and
effect - where something exciting happens when the switch is pressed - to using
a switch with a word processor, where single presses of the switch can be used
to type or control the computer.
In order for any of this to happen, the user will require a suitable switch
connected to the computer via an interface, such as the Crick
USB , or, through one of the switch sockets on the IntelliKeys
Classic or IntelliKeys
USB keyboard. You will also require software that has been adapted to work
via switches.
In some cases the user will have already practised and demonstrated switch skills, using toys or other devices. Simpler switch operated equipment will be a desirable way to produce and assess switch skills. However, for some users who may not have responded to toys or other equipment, the computer may offer advantages.
When someone is in the early stages of developing switch skills it is important to remember that they will be introduced to a lot of new activities at the same time. Care is needed to ensure that the source of any problems are carefully identified. For example, a child poorly seated in front of a monitor set upon a high table may not actually be able to see the screen. In this case, the child is unlikely to develop the concept that their switch press is causing something to happen on that screen.
Before attempting to give the child control with the switch, it is important to ascertain as much as possible whether they enjoy, or are aware of, the reward being produced by the computer. It is best to do this by having an adult operate the switch and watching the child's reaction to it. For example, if an object moves across the screen, are they tracking it with their eyes.
Software that is simple and bright in nature is best. Something where the screen is completely blank and then an image will appear. Using the volume control on loudspeakers, it should be possible to check whether the child is responding to the sound, to the image, or to both.
In the early stages it is best to have both sound and image. If, however, there is any doubt about the child's hearing or visual ability it may be possible to check which is their preferred response and use that further to give them control of the computer.
Having established what the child is interested in on the computer screen, the next desirable step is to see if they can be provided with a method of controlling this for themselves.
In the early stages of control a program that can produce a reasonably exciting
and dramatic reward for a single switch press would be best. Switch programs,
such as Big Bang, provide auditory and visual rewards from a single switch press.
Throughout this learning period consistency of the positioning of the equipment and the switch is necessary. All verbal prompts used by those working with the child should be the same i.e. 'hit it', 'press it', 'now' etc.
If the child is going to be able to press their switch and see and enjoy the reward, careful positioning of the monitor, the child, and switch is necessary. Consistent verbal and physical prompts at this early stage offer encouragement. However, the aim is to get the user to interact with the computer, so, as their control develops external prompts should be reduced.
As in all activities with children with special needs, sufficient time should be given for them to become familiar with the switch activity. Frequent, short, practice sessions, once or twice a day, over a period of time will be necessary in order to develop their switch skills fully.
In some cases, children will very quickly master the task. When this happens, provide further new activities, rather than have them do the same thing over and over again.
Using the computer should not always be seen as a progression from other switch devices. As the child is mastering and developing their switch skills, they should be given a range of activities, including the computer and other switch devices.
Cause and effect
It can be quite difficult to
ascertain fully whether a child has grasped the concept of cause and effect.
For example, a child can be observed pressing the switch and then looking up at
the screen and listening to the reward. This may not always mean that they have
fully established in their mind that they are causing this reward to happen: it
may be that they quite like pressing the switch as an activity, then, when
there is something nice happening on the screen, or they hear a nice sound,
they also like watching that.
Careful observation and sound knowledge of the child and how they function in other circumstances may be necessary to ensure that they have fully developed the desired concept of cause and effect. Before moving on to more complex software, give the child time to develop their switch skills to a point where they become reasonably automatic, so that they are able to concentrate their thoughts and efforts on the result of their presses, not on their switching.