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Access Features in AAC

Introduction
Identifying the most appropriate access method for an individual can be immensely complex if he or she has significant motor impairments. This website is not designed to help you make such decisions. It is very important that you have assistance in making these decisions from a team of AAC experts. See the Introduction to Device Features for leads on locating such individuals.

There are two broad categories of access methods for AAC devices and strategies. You can find more information on these access methods in Dowden & Cook (in press) listed in the References.

1) Direct selection
2) Indirect selection

1. Direct Selection Methods: Direct selection means that the individual specifically indicates the desired item in the selection set, without any intermediary steps (Dowden & Cook, in press). There are three types of direction selection methods used for AAC devices and low tech strategies:
   a) pointing with physical contact & force
   b) pointing without physical contact
   c) pointing with contact and no force
   d) picking up and exchanging

a. Pointing with physical contact & force: This is the most common method, used in the greatest number of devices. Access can be achieved through finger pointing or via headwand or mouthstick. Here are some of the many devices accessible via this type of direct selection:

     LightWriter from Zygo Inc.:

                  
          (Click picture to enlarge)

     AlphaTalker from Prentke Romich Co.:

                  
          (Click picture to enlarge.)

b. Pointing without physical contact: This is the method used by devices accessed via eye-gaze or light pointers, for example:

     Pathfinder (using a light pointer) from Prentke Romich Co.:

                  
          (Click picture to enlarge.)

     ERICA (using eye-gaze) from Erica Inc.:

                  
          (Click picture to enlarge.)

c. Pointing with contact but no force: This is the most common method used with communication books and boards, where the user touches the item but does not need to provide pressure:

     Communication Placemat for a Child:

                  
          (Click picture to enlarge.)

d. Picking up and exchanging: This method is often called the Picture Exchange Communication System (PECS), but any type of printer or tangible symbol can be used this way. I

     Picture Exchange Communication System (PECS):
              (Image from Communication Made Easy)

                  
          (Click picture to enlarge.)

  
2. Indirect Selection Methods: Selection via an Indirect Selection Method involves intermediary steps by the device before the individual can make a selection. There are three categories of indirect selection, usually considered only for individuals who cannot use the faster direct selection methods (Dowden & Cook, in press).

a. Scanning with Single or Dual Switches: This access method is the most common type of indirect selection, where the selection set is presented sequentially either visually or aurally. The user can make a selection in many different ways.

This access method is available on a wide variety of large and small devices, for example:

     Vanguard from Prentke Romich Co.:

                  
          (Click picture to enlarge.)

     Holly.com from Communication Devices, Inc.:

                  
          (Click picture to enlarge.)

    An Alphabet Board for Partner Assisted Scanning: For more information on this technique, see the glossary: Partner Assisted Scanning

                  
          (Click picture to enlarge.)

b. Directed Scanning: In directed scanning, there are elements of direct selection and single-switch scanning. The individual uses a multi-switch array, for example a joystick or arrow keys to move the cursor in the desired direction and to make a selection. There are not many devices that are capable of directed scanning, but they include:

     DynaVox 3100 from DynaVox Systems, Inc.:

                  
           (Click picture to enlarge.)

     Pathfinder from Prentke Romich Co.:

                  
          (Click picture to enlarge.)

c. Coded Access: Dowden & Cook (2002) use the term "coded access" to describe the use of a sequence of body movements that retrieve unique items in a selection set. They emphasize that this is distinct from a sequence of selections to make a message, as in encoding. For more details, see Dowden & Cook (2002). This access method is not available in most devices. Here are some devices that permit coded access, however:

     Macaw from Zygo Inc.:

            
          (Click picture to enlarge)

     ETRAN Board - Accessed through Eye Codes:

     Darci Too from The Darci Institute:

                  
          (Click picture to link to DARCI.)

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University of Washington, Dept. of Speech & Hearing Sciences, Tele-Collaboration Project. © 1999-2002, UW-SPHSC, including all photographs and images unless otherwise noted. Comments: tcollab@u.washington.edu. URL: http://depts.washington.edu/augcomm