Tele-Collaboration in Speech and Hearing Sciences: Augmentative and Alternative Communication



About scanning
   What is scanning?
Scanning demo









*Introduction & Demo

What is scanning?

We can give you the dry, textbook definition......
Scanning is where the items in the selection set are presented sequentially over time and the user makes a selection indirectly, typically via one or two switches. (This is in contrast to direct selection where all items in the selection set are available at the same time and the user goes straight for the one he/she wants)

But describing scanning is nothing like seeing scanning, so here is a computer simulation. After you look at it for a moment, read further as we describe the aspects of scanning that are important to understand.

Scanning Demo: Varying the speed

Start the demo by clicking with your mouse on "Start" then
control the switch by clicking on the "Switch" button.

In the scanning demo above, you should note the following;

1) This is single switch scanning. When you click your mouse on the "switch" the scanner will select the item that was highlighted at that moment. Go ahead and practice writing some words.

2) You can control the scanning speed in this demonstration. When you click on "slow" or "fast" you will see that you can make the cursor travel at different rates through the selection set. You should practice in particular with the "fast" scanning speed and see how difficult it can be to compose a message accurately when the speed is too fast for you.

3) The scanning shown here is "linear" where the cursor moves from one item to the next through the entire set. You can see how slow linear scanning is. We will present other scanning patterns shortly.

4) This is scanning with the alphabet as the selection set. Scanning can also be done with simple line drawings, complex symbols or printed words as we will show you.

Continue on to "Scanning Patterns"   


University of Washington, Dept. of Speech & Hearing Sciences, Tele-Collaboration Project. 1999-2000, UW-SPHSC, including all photographs and images unless otherwise noted. Comments: URL: