SYMBOL SET HIERARCHY
By Liz Mann, MA, CCC/SLP
The selection of an appropriate symbol system for a child needs toÂ address several aspects of their abilities and needs. Just as a childÂ crawls before they walk, so to does a child’s symbol selection follow aÂ natural hierarchy. A child whoÂ does not have an understanding of basicÂ cause and effect should not be using a high tech communication deviceÂ with abstract picture symbols. Just because a communication deviceÂ is expensive and has lots of bells and whistles, doesnâ€™t necessarilyÂ make right for your child.
There is a symbol set hierarchy that can beÂ followed to determine which communication system would work best. Â Of course every child and every situation is different, but this hierarchyÂ can help to give you a broader knowledge of the natural progression of using a communication system. (See illustration below)
A pre-symbolic communicator is someone who doesnâ€™t understandÂ that picture symbols or objects represent something real. We needÂ to start by teaching the pre-symbolic communicator basic cause andÂ effect. They have to understand that when they purposefully act onÂ their environment they can get something highly motivating to themÂ in return. The key is to find activities that are highly motivating to theÂ child by establishing response patterns. A child at this level might use aÂ single switch to teach basic cause and effective or a single message voiceÂ output device like a BigMack.
After a child has mastered non-symbolic communication, the next stepÂ is for the child to learn how to use objects, photographs, or pictureÂ symbols. The child will begin with object-to-object representations. The child will exchange or select an object in order to receive itsÂ identical pair. When they understand that an object represents anotherÂ object you can usually move on to placing a photograph of the object with the object. You have to teach the child that photograph representsÂ the object desired. It is still very important to use highly motivatingÂ activities. A child at this level might use a mid tech communicationÂ device such as a GoTalk 4 or just a couple of single message voice outputÂ devices.
After the child fully understands photographs you can move ontoÂ picture symbols or line drawings. When the child is able to understandÂ line drawings, they are able to refer to objects that are not right in front of them. It is important to determine how many pictures they are ableÂ to distinguish between at one time, what size should the picture symbolÂ be, whether or not they can string two or more pictures together, and if they are able to identify items by label, function, and category. If aÂ child is able to identify items by label, function, and category, and theyÂ show emerging skills in their ability to string to more picture symbols together they a probably ready for a high tech communication device.
Children who use Augmentative and Alternative Communication orÂ AAC require a lot of practice with their communication systems. It isÂ important to remember that you are teaching your child a new language, and they need to have plenty of practice and be provided with lots ofÂ models. For child to want to communicate they have to know that theirÂ attempts at communication are meaningful.