Augmentative and Alternative Communication (AAC)

Persons with neurological disorders such as cerebral palsy may experience varying degrees of language and/or speech pathology. Individuals with cerebral palsy may experience significant oral-motor dysfunction which may preclude normal speech production. Additionally, cognitive deficits may occasionally be present which delay usual language development (this, however, should never be assumed). Speech pathology must be addressed promptly as the ability to express one's self and communicate with others is crucial for social and cognitive development.

Some form of Augmentative and Alternative Communication (AAC) is often required for those with significant communicative disability. AAC in effect is defined as any combination of expressive modalities, other than the spoken word, which assists an individual to communicate with others. These modalities may involve the use of various types of symbols, signs, gestures, or the written word. Also included within AAC are digital text-to-speech devices, such as the Pathfinder, as well as visual output devices (such as speech to text). A variety of assistive technology devices are available. Although AAC often incorporates the use of assistive technology, this is not necessarily the case. Communication may be enhanced by non-technical interventions as well. Whenever possible, AAC should be used to supplement rather than replace speech.

AAC intervention often involves the identification and expansion of specific communication signals currently used by an individual. These signals are in effect symbols. Symbols are the basic elements of all language. Symbols represent an arbitrary yet accepted relationship between a sign and its intended meaning. Some types of symbols include graphic (e.g., writing), auditory, gestural (sign language), tactile, or vocal. Within the context of AAC, symbol use may be analyzed and expanded upon in order to establish a common basis for communication. Additionally, several artificial symbol sets have been constructed for use in AAC and are commercially available. Some examples of these include lexigrams, Sigsymbols, and Blissymbols. Symbol systems typically utilize a display screen with an interactive interface. Symbol selection proceeds by use of direct selection or scanning. In direct selection, the user indicates his or her intended symbol by indicating their choice from a static display of items, via pointing, eyegaze, or other method. Scanning symbol selection involves scrolling displays of items from which the user indicates choice, typically by releasing a button. Use of such symbol systems potentially allows more expressive communication than use of simple symbol sets.

Occasionally a person with significant motor disability may require the use of additional adaptive technology applications in order to operate certain AAC devices. These applications may include head pointers, voice recognition software, or eye-gaze selection/scanning equipment. Healthcare practitioners should be aware of the various types of AAC that are frequently used.

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Ratcliffe, A, & Cress, C. (1997). Communication isn't just talking. ASHA Journal, 39(2), 1-9

Venkatagiri, H.S. (2002). Clinical implications of an augmentative and alternative communication taxonomy. Alternative and Augmentative Communication, 18(1), 1-24

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