Assistive Technology - Augmentative and Alternative Communication

Augmentative and Alternative Communication

Augmentative and alternative communication (AAC) is an umbrella term that encompasses methods of communication for those with impairments or restrictions on the production or comprehension of spoken or written language. AAC systems are extremely diverse and depend on the capabilities of the user. They may be as basic as pictures on a board that the are used to request food, drink, or other care; or they can be advanced speech generating devices, based on speech synthesis, that are capable of storing hundreds of phrases and words.

Modern use of AAC began in the 1950s with systems for users who had lost the use of speech following surgical procedures. During the 1960s the use of manual sign language grew greatly, but it was not until the 1980s that AAC began to emerge as an area in its own right. AAC is now used for a wide variety of speech impairments. Studies show that AAC use does not impede the development of speech, and may even result in a modest increase in speech production.

A great diversity of diagnoses, including cerebral palsy, intellectual impairment, autism, and many others, cover varying degrees of communication impairment. AAC interventions are highly individualized, taking into account specific abilities of language comprehension, social-relational characteristics, learning strengths and weaknesses, and developmental patterns for specific types of intellectual disabilities. AAC can be used to aid both spoken and written language, and can supplement or replace speech and writing as necessary. AAC can be a permanent addition to a person's communication or a temporary aid. The systems used in AAC include gestures, hand signals, photographs, pictures, line drawings, words and letters, which can be used alone or in combination to communicate.

Aided AAC makes great use of symbols, particularly for non-literate users, as well as a large variety of input methods. The specific access method will depend on the skills and abilities of the user. Body parts, pointers, adapted mice, joysticks, or eye tracking could be used, whereas switch access scanning is often used for indirect selection. In many cases, rate enhancements methods may be used to speed up the generation of messages. Clearly, an evaluation of a user's abilities and requirements is necessary to match a user with the most appropriate AAC method, input approach, and vocabulary. This evaluation requires the input of family, particularly for early intervention. Respecting ethnicity and family beliefs are key to a family-centered and ethnically competent approach. Adult AAC users generally have satisfying relationships with family and friends and engage in pleasurable and interesting life activities.