SENSwitcher Software - Using Assistive Input Devices

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Using Assistive Input Devices

SENSwitcher can be operated using a wide range of input devices, which include:

• The left mouse button or equivalent on roller ball, joysticks etc.
• The space bar or equivalent on standard or adapted keyboards.
• Concept keyboards - An overlay is available from the  download area.
• Any switch via an interface which can emulate the space bar or left mouse button

When using the program with people with profound and multiple learning difficulties, or those with restricted or involuntary movements, it is important to ensure that the correct switch is being used and that it is positioned so that the user can access it without physical discomfort

Little has been published on the subject of switch assessment although some information is available on the Internet and in books. The Priory Woods School Assistive Technology Skills Progression document (which can be downloaded from the Northern Grid web site offers the following advice.

"An accurate assessment will be required to identify a reliable, consistent and repeatable movement that the child will be able to make from their normal seating position (this may include side lying benches and prone standing frames if this is the child's MOST comfortable position for accessing the computer). Several issues also need to be considered;

• · The child's medical condition including expected course and prognosis and other related medical issues such as skin conditions, which could affect movement.
  
  
• · Physical functioning, which movements are voluntary and which are involuntary. What is the range of movement? Is it accurate? How quickly can the movement be made and how much pressure can be applied?
  
  
• · Is there any sensory impairment, which may affect the use of the equipment? Visual difficulties, hearing impairment, tactile problems?
  
  
• · Are there any known perceptual problems to consider? Hand to eye coordination, tracking or scanning difficulties, problems with the left or right side, spatial relationships?"

Switch assessments should be multidisciplinary, drawing on the skills of the teacher, occupational therapist, physiotherapist, speech therapist and the child's parents to help identify movement patterns, known motivations, likes and dislikes etc. to aid the assessment process. Correctly identifying a reliable, repeatable and consistent movement and selecting the right switch to match that movement are critical factors for successful learning for people who require assistive devices to enable them to access the curriculum.

CASE STUDY ONE - Using Switches Roger (5) is a young boy with ataxic cerebral palsy and a severe learning difficulty, who is just learning to use switches to operate the computer. Following an assessment a suitable switch was identified and mounted near to Roger's right hand. Roger activates the switch by lateral movement of his hand and arm, a movement, which is reliable, repeatable, consistent and comfortable for him in his normal seating position. SENSwitcher was used initially at a single press cause and effect level to encourage Roger to activate the switch. Roger quickly understood and internalised the relationship between the switch and the on-screen animations and rapidly moved on to switch building (activating the switch a set number of times to 'build up' the screen before triggering the animation).

Teachers and other professionals are currently working with the Northern Grid to develop a web based 'expert system' to provide a framework for switch assessments. The system will be published on the Northern Grid web site in the near future.

There is a vast array of switches available on the market today, covering many different methods of activation and placement. Information and advice is available from a number of commercial companies on the Internet, their contacts details can be found in the
 appendix to this document.

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