Assistive Technology's: Augmentative & Alternative Communication (AAC) Equipment

Overview of Augmentative & Alternative Communications Systems (AAC)

Perhaps the most often requested assistance from parents is with communication. AAC helps to build a bridge between what the child knows and wants to say and their inability to express it in words due to muscle and motor planning issues. An electronic device can help bridge the gap and enable a child to communicate his needs and thoughts.

There are many different options available to do this, and they range from very low tech (paper and pencil written communication) to very high tech (switch activated electronic devices with synthesized speech output). Cost can vary from $20 to $20,000 depending on the needs of your child. In most cases, a thorough evaluation should be done by a competent speech and occupational therapist to determine which technologies to consider. The content on this site is merely a tool to help you understand the many available options which you can discuss with your therapist(s).

On this site are somje examples of currently available electronic devices that may be suitable for your child depending on his/her needs following a complete evaluation. Often times, multiple solutions may work, and it is usually recommended to start with the least amount of technology whenever possible. whenever possible. Through extended evaluations and loan periods, your therapist(s) can better determine the best fit for your child.

Glossary of frequently used AAC terms:

DECtalk: The most common speech synthesizer used in communication devices. Voices can be programmed to simulate both female and male voices for children
through adults. (see this link for more info on DECtalk)

Digitized Speech: Unlike synthesized speech which relies on software to create spoken words, digitized speech is simply "recorded" speech. The programmer records their own words into the device, and the user then plays them back. This method requires lots of memory to store multiple phrases and cannot make words which aren't directly recorded.

Direct Selection: With direct selection, "what you push is what you get". Like a normal keyboard, pressing the "L" key, displays an "L" on the screen. This method does not require a sequence of events like "indirect selection", but simply one action produces an effect.

Dynamic Display: A dynamic display changes as you move through sequences of "communication boards" automatically. The device can be programmed to change screens when certain buttons are activated. For example, one can program a "meal" board to change to a "lunch options only" board automatically by the child pressing the "I want to eat lunch" button. This requires good memory and problem solving ability by the user, and can be extremely valuable to the intelligent person who wants
to independently use large vocabulary and context choices throughout the day.

Indirect Selection: This method requires the user to activate a sequence in order to elicit a desired response. For example, a user may use a switch to activate a scanning cursor. When the cursor reaches the desired target, the switch is activated again to "select" the target.

Keyguard: A keyguard is used to help guide the user to the correct location of a direct selection device like a keyboard. It allows the user to drag their hand(s) across the device without accidentally hitting undesired keys or selection. Holes are made over the correct areas for more accurate selections.

Membrane Keyboard: A membrane keyboard is one flat surface. The advantage is that you can make overlays which customize the layout to fit your specific needs. The disadvantage is that it is only 2 dimensional, and it can be easy to activate undesired fields without a keyguard.

Minspeak: This is different from a dynamic display as described in this glossary in that it is not a multiple "level" or overlay system. It uses pictures which carry certain meanings depending. One can string many pictures together to create a complete idea, and these pictures change in meaning depending on the context of the previously selected pictures. If this sounds confusing, you are not alone. This requires a great deal of training to learn how to use this, but can be very useful when one become proficient. Click here for more info on this, and for a comparison (biased) on Minspeak vs dynamic level systems.

Scanning: Scanning is frequently used with indirect switch selection. Typically, activation of the switch initiates a scanning sequence (linear, column-row, etc..). A second activation will select the user's desired choice. Many variations of this concept exist depending on the number of switches, and desired responses. Scanning rate is usually user adjustable.

Synthesized Speech: This is speech that the computer generates to closely resemble a human voice. A digital answering machine is an example of a product that uses synthesized speech. This method allows the computer to generate an unlimited number of possible spoken words, and takes up little memory. The most common speech synthesizer used in communication devices is DECtalk.

Word Prediction Software: Word prediction works well for "slower" typers and also for those who have difficulty with spelling, but want to be able to write proficiently. The software "predicts" what you are typing as you go. With each keystroke, the choices continue to narrow down to your desired word, until the user simply hits one key or switch to select the desired word without having to type the whole thing out. CoWriter is an example of word prediction software.

Coping.org is a Public Service of James J. Messina, Ph.D. & Constance M. Messina, Ph.D., Email: jjmess@tampabay.rr.com Š1999-2007 James J. Messina, Ph.D. & Constance Messina, Ph.D. Note: Original materials on this site may be reproduced for your personal, educational, or noncommercial use as long as you credit the authors and website.