Identification

• Augmentative and alternative communication, or AAC, includes all forms of communication other than oral speech. These include communication that everyone uses such as gestures, writing, facial expressions, pictures and symbols.
  
  AAC also includes special augmentative aids such as electronic devices, pictures or symbol boards that enable individuals to express thoughts, emotions, wants and needs. These devices enable those with severe communication disorders to build their self-worth, independence, academic and vocational skills, and social connections.
  
  

Function of Direct Selection

• Basically, there are three types of AAC: direct input,scanning and encoding. Direct input is the fastest.
  
  With direct input, the person indicates the desired word by pointing a body part or a pointing aid at a symbol/picture/word. Pointing aids may be a stick held in the fist or the mouth, or a light beam attached to the head by a headband.
  
  For those with poor motor control, other devices may include a camera and high-speed microprocessor that detects small eye movements. For those with some speech, a computer decodes their spoken words and prints them out.
  
  

Function of Scanning and Encoding

• Another type of communication is scanning. Choices are presented and the person indicates her choice by an eye blink or a nod, or a light goes over the rows of choices and she activates some type of switch to stop on the desired symbol.
  
  A variation is encoding, a sort of speed-dialing process where a numerical code represents a common phrase. For example, the number 1 could mean "I want a drink," 2 means "I am hungry" and so on.
  
  

Features

• A communication device may use one of three different types of representation: single meaning pictures, alphabet-based systems and semantic compaction.
  
  With single meaning pictures, an advantage is that literacy is not required, and the time it takes is short. The disadvantage is that a large amount of picture symbols must be available to the person for adequate communication.
  
  With alphabet-based systems, literacy is required and it takes longer to communicate thoughts, but the amount of symbols is limited to the alphabet. Word prediction can speed the process somewhat, but can be inaccurate or bothersome.
  
  For semantic compaction method devices, a short combination of symbols is used. Literacy is not required but training is needed to use the system well.
  
  

Types

• AAC includes low-tech methods, such as pencil and paper for those with both literacy and motor skills, to communication boards or books, to devices that produce speech or written words based on person's input. The speech-generating device, or SGD, may produce speech in a variety of languages.
  
  To determine the best augmentative and alternative communication technology, a person should consult with a trained speech pathologist to consider the person's level of functioning, communication strengths and weaknesses, and communication needs. A system should be set up based on the individual's unique needs and capabilities.