Switch Scanning: A Powerful Access Tool

Transcription

1 Switch Scanning: A Powerful Access Tool Eleanor Craighead B.Sc (Log), R.SLP, S-LP(C), Augmentative Communication Specialist Renfrew Educational Services Jared Shore R.SLP, O.T. (C) Assistive Technology Team Renfrew Educational Services Definitions cont. Scanning Indirect access method for individuals with significant physical limitations, as an alternative to direct access or keyboard/mouse access. This involves the use of one or more switches to access a choice from a selection of symbols or characters. Presentation Outline Definitions When to use scanning Pros and cons of scanning Switches Site selection Switch mounting Switch training Using switches with software Using switches with communication devices Questions Scanning Definitions cont. Dedicated/Automatic Scanning - Scanning is automatic. User presses switch when scan highlights desired symbol(s). Step Scanning - Uses more than one switch. One switch steps through the choices. The other selects the symbol(s). A dwell can also be used. Inverse (Hold) Scanning Scanning is activated by holding down the switch. User releases the switch to stop the scan. User can select by dwelling on the symbol or by activating a different switch. Linear/Step scanning: the indicator moves across the cells one at a time, each time the switch is activated Definitions Switch - a device that controls the flow of current in an electric circuit, by turning the current on or off. Definitions contd. Row column scanning (column row scanning): scanning occurs across the rows first, and then down the column selected (or vice versa) Quadrant scanning: the page is divided in 4, and the scan runs through each quadrant, and then does rowcolumn scanning within the chosen quadrant. Dwell selection in automatic scanning: the indicator will select the cell after a period of inactivity which can be defined by the user. Predictive selection: only the choices that can logically follow the first selection are scanned (MINSPEAK feature) 1

2 When To Use Scanning Physical access issues primary (intended for individuals who do not have sufficient motor control for direct selection techniques) Lighted scanning visual issues FL4SH Auditory scanning cortical-visual impairment (CVI) or low vision Partner-Assisted scanning: usually low tech What Are Switches? Mechanical Capability vs. Proximity Mechanical Switch Manual activation of switch results in continuation of circuit Proximity Switch - Proximity switches open or close an electrical circuit when they come within a certain distance of an object. Infrared proximity switches work by sending out beams of invisible infrared light. A photodetector on the proximity switch detects any reflections of this light. These reflections allow infrared proximity switches to determine whether there is an object nearby. Pros of Scanning Independence! Able to get message across Access can be controlled by client Switch Site Selection 1. Reliability (consistency) of motor movement 2. Volitional nature of movement 3. Ease of movement 4. Endurance 5. Efficiency of movement 6. Previously successful movements 7. Ability to perform timed-response CONS OF SCANNING SLOW! SLOW! SLOW! Repetitive strain injury Additional equipment (switches, mounting, etc) additional cost More equipment involved = more opportunities for breakdown Fixed vs. Flexible Switch Mounting 2

3 Switch Training Software Classroom Suite Training cont. Boardmaker With SD Pro/Boardmaker + Learning Two Switch Step Scanning SCANNING WITHIN SOFTWARE: SWITCH INTERFACE (ALWAYS) IntelliSwitch BoardMaker with SD Pro/Boardmaker + Swifty Switch adapted mice DJ Switch Interface Intellikeys Keyboard 3

4 Symwriter ChooseIT! Maker It turns your text, images and sounds into choice making activities and quizzes that are automatically accessible using a mouse, whiteboard, touch monitor, keyboard or switches. It's great for helping switch users to learn to make choices using scanning techniques. Has single (automatic scan) and two switch scan settings along with programmable options (e.g. scan speed, auditory scan) The Grid 2 Switch Access Software Applications Select from several scanning strategies; use standard line scanning or first use section scanning to identify the general area of the display where the target point is located and then use line scanning to precisely position the mouse.. Once you have selected the location, choose from several button options including click, double click, drag, left or right mouse button, etc The Grid 2 (contd) The Grid 2 supports the use of up to 8 switches, although most people use just one or two. switch features include: Simple or row-column scanning Automatic, tap-to-advance or hold-to-advance scans Adjustable switch timing Hold a switch for a long time for a different action Use additional switches for extra functions Filtering of accidental switch presses Switch settings preview (for testing settings as you change them) Switch Access Software Applications cont. Discover:Switch is the only switch with scanning computer access built-in. Use any of the readymade scanning setups to get pupils working and learning straightaway. Because Discover:Switch works like the other Discover products, it's easy for teachers to learn and adapt for pupil's individual learning needs. **Replaced by DiscoverPro Software to be used with Intelliswitch 4

5 Free Web Resources Generating Devices: DYNAVOX Level 1 : Shape/Objects 10 shapes and objects which move in a variety of directions across the screen with animations that are activated if the user presses when the object moves into the target area. Level 2 : Scenes 10 scenes where the user receives an animation reward if the user activates at the right time. Objects align in both horizontal and vertical directions. Free Web Resources cont. Generating Devices contd. Dynavox products Generating Devices: PRC devices SINGLE SWITCH SCANNING 2 SWITCH SCANNING SCANNING OPTIONS IN PRC PRODUCTS SB VT/VG ECO SB VT/VG ECO PREDICTIVE SELECTION ON/OFF Dynavox contd. SCAN TYPE STEP/HOLD SCAN TYPE STEP/HOLD/AUTO SCAN TYPE AUTO/HOLD SCAN TYPE STEP/AUTO ACTIVATION DELAY ON/OFF SCAN AUTO RESTART SELECTION TYPE AUTO/MANUAL USE SCREEN AS SWITCH SCAN MODE 1/2 SCAN DIRECTION ROW/COLUMN COLUMN/ROW SCAN DIRECTION LINEAR L-R TOP-BOTTOM SCAN DIRECTION QUARTER ROW/COLUMN QUARTER COLUMN/ROW DIRECTED AUTOSCAN/STEPSCAN + EH + EH 5

6 References and Resources Dynavox contd. Webster's New World College Dictionary Copyright 2005 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc. Journal of Rehabilitation Research and Development, September/October 2000, Vol. 37(5), p Generating Devices contd. Static display devices: Smartscan (AMDI) Message Mate AdVOCAte FL4SH The handbook of augmentative and alternative communication, Sharon Glennen, Denise C. DeCoste (Google Books) Questions? 6