Augmentative and Alternative Communication
Introduction to AAC
AAC is used by people who, some or all of the time, cannot rely on their speech. For example, an individual who has not yet developed understandable speech might use a speech output device to produce words. But, as his speech becomes clearer, he may need to use this device in only some situations.
AAC incorporates the individual's full communication abilities and may include any existing speech or vocalizations, gestures, manual signs, and aided communication. AAC is truly multimodal, permitting individuals to use every mode possible to communicate. Over time, the ability to use AAC devices may change, although sometimes very slowly, and the AAC system chosen today may not be the best system tomorrow. In any case, an AAC system is an integrated group of four components used by an individual to enhance communication. These four components are symbols, aids, techniques, and strategies.
By recent estimates, well over 2 million persons who present with significant expressive language impairment use AAC. AAC users encounter difficulty communicating via speech due to congenital and/or acquired disabilities occurring across the lifespan. These conditions include but are not limited to autism, cerebral palsy, dual sensory impairments, genetic syndromes, intellectual disability, multiple disabilities, hearing impairment, disease, stroke, and head injury.
Bottom Line: Augmentative and alternative communication (AAC) is an area of clinical practice that attempts to compensate (either temporarily or permanently) for the impairment and disability patterns of individuals with severe expressive communication disorders (i.e., those characterized by severe impairments in speech-language, reading, and writing).
Aided Versus Unaided Communication
Typically, forms of AAC are divided into two broad groups, known as unaided and aided forms of communication. Unaided forms of communication consist of nonverbal means of natural communication (including gestures and facial expressions) as well as manual signs and American Sign Language (ASL). These forms of communication do require adequate motor control and communication partners who can interpret the intended message. Aided forms of communication consist of those approaches that require some form of external support, such as a communication board with visual-graphic symbols (i.e., pictures, photographs, line drawings, Blissymbols, printed words, traditional orthography) or computers, handheld devices, or tablet devices with symbols, words, letters, or icons that "speak" through synthetically produced speech or recorded natural (digitized) speech.
Families often initiate the use of unaided forms of communication, especially gesture and facial expression, because they are natural ways of supporting communication. The introduction of sign language as an unaided form typically involves some level of support from an individual's team. Like other forms of AAC, sign language can augment or provide an alternative to speech. For some individuals, sign language appears to provide an important first step for later spoken language development. Other individuals continue to rely on sign language as their primary communication mode, but there is no evidence suggesting that the use of sign inhibits the development of speech. If sign language is selected as a means of communication, it is important for communication partners to also learn sign language so that they can model and reinforce the signs the individual is learning.
When aided forms of communication are selected, an interdisciplinary team is typically involved in the decision-making process. Speech-language pathologists (SLPs), occupational therapists, physical therapists, educators, and families should work together to identify initial forms of AAC to implement and continue to work together to support the development and use of the system over time.
Each form (aided or unaided) of communication takes time and cognitive resources. For example, sign language requires the communicator to recall and produce the hand shapes and motor movements for each sign. Pictures and symbols have to be located and selected, and technology-based systems introduce myriad operational demands. These are just some of the features of therapy approaches that are dependent upon the characteristics of the client and will influence the choice of communication form(s).
At the same time, communication partners influence the forms of communication that are best in each context. For example, sign language may be the best form of communication when the communication partners understand sign, but another form of communication may be required with communication partners who do not. Individuals with very complex needs and a limited communication repertoire can learn to use different systems in different contexts.
Many individuals with communication disorders have learned to communicate with sign language. Like other forms of AAC, sign language may enable an individual to communicate when he or she is unable to adequately communicate with speech. Sign language can be easier to teach than speech, because parents and teachers can help individuals form the hand shapes of sign language. It is important for communication partners to also learn sign language, so that they can model and reinforce the signs the individual is learning.
Bottom Line: AAC can involve external aids (books, technology) or natural communication, such as facial expression, body posture, gesture, or sign language. The best form or forms of communication are determined by the needs of the individual with disabilities and their communication partners.
Decision Making About AAC Systems and Interventions
Who Can Benefit From AAC
The currently accepted evidence in the literature suggests that no specific skills are prerequisite for successful use of AAC in the broadest sense. AAC is an intervention approach that can be the beginning of communication development for an individual. A number of AAC options are available to begin the intervention process.
The decision to introduce AAC should be made in consultation with a team of professionals who can assist with issues specific to system/device prescription, procurement, and use. The lead professional in this endeavor will typically be the SLP. Others who might be involved include but are not limited to occupational therapists, physical therapists, rehabilitation engineers, special educators, vision specialists, audiologists, and psychologists. Finally, when considering AAC, parents and professionals must remember that there are no prerequisites to AAC use. That is, all individuals should have access to AAC systems or devices that promote effective communication.
Bottom Line: AAC is probably right for an individual when he or she presents with a severe expressive communication impairment that interferes with or prevents development and use of oral language.
One variable affecting use is understandability, and understanding is affected by many contextual variables, such as the familiarity of the communication partners with different modes of communication (signs, pictures, speech-generating devices [SGDs]).
A common view among SLPs and other communication specialists is that an individual will eventually use pictures more than other forms of communication, because pictures may be more readily understood by a range of communication partners in various environments. Each type of communication takes time and cognitive resources. For signs, the communicator has to recall and produce the motor movements. For pictures, the communicator has to locate and select the pictures. Perhaps for these reasons some individuals with severe cognitive disabilities may prefer to use signs (rather than pictures or photographs) when communicating with partners who understand sign language.
For individuals with severe disabilities, it can be helpful to encourage (and teach) multiple forms of communication. Individuals may need to be taught when it is appropriate to use different types of communication. For example, the individual may sign when interacting with parents at home but may use a picture-based system with nonsigners. Individuals with very complex needs and a limited communication repertoire can learn to use different systems in different contexts.
SGDs also provide a way for an individual with severe cognitive disabilities to communicate independently, because SGDs produce spoken communication even though the individual is using pictures to create the message. These spoken messages can be readily understood by communication partners who may not be familiar with sign language.
Bottom Line: Everyone uses a variety of means to communicate. The “best” form or forms of communication for any individual are those that the individual will use to communicate with other people.
AAC Intervention When a Client Is Partially Intelligible
Special education law requires each student's needs to be evaluated, with the student's educational team making determinations about the services and supports that are needed for the youngster to access a free, appropriate public education. A communication assessment should be conducted to determine those educational settings in which an individual's unintelligibility poses a barrier and also the means of AAC support that is both appropriate for and preferred by the student. This information should be brought back to the team so it can determine if, when, and how AAC supports will be provided. If the team agrees that the individual needs AAC supports, then the nature of the tools/strategies to be used and the settings in which they are to be used should be specified.
Bottom Line: AAC interventions are used whenever individuals are unable to rely on speech to meet all of their daily communication needs.
Considerations When Choosing Visual Symbols
Designing an AAC system that employs graphic symbols for an individual user necessitates decisions about the type of communication device and the type of symbols that will be displayed. This is not a simple task, because an individual's ability to communicate successfully may hinge largely on the accurate representation of words, phrases, or expressions that span a range of communication functions. One issue to consider is the representational nature or type of symbols. Symbol sets vary from picture-like graphics (e.g., Mayer-Johnson Picture Communication Symbols) to the combination of different elements or forms to depict meanings (e.g., Blissymbols). For individuals with some orthographic skills, symbol selection may not be an issue, because they can produce any possible words or sentences by using letters to spell out their messages. Issues to consider in the selection of devices are their capacities in terms of the number and size of the symbols available and the type of display (static, dynamic) offered.
Bottom Line: The selection of symbols and of a device is determined by the communication and linguistic profile of the intended user.
Considerations for Device Selection
It is important that a clear picture of the individual's current capabilities and needs are considered in order to select communication devices, communication techniques, and the symbol systems or symbol sets.
It is also important to contrast high- and low-tech devices. The advantage of using nonelectronic communication options (i.e., low tech or light tech) is that these displays can take on many forms and can be tailored to the abilities and needs of individuals across various activities. The primary advantage of electronic (high tech) devices is that they provide output or "talk." When the individual touches a symbol on a high-tech device, output for the message is relayed generally with voice output. Using electronic or high-tech devices in conjunction with other techniques and/or low-technology options may best serve the person's need to communicate.
Different demands are also placed on AAC users who operate on static versus dynamic displays. In static or fixed displays, symbols are arranged on individual pages; the symbols do not change position on the display. In such systems, one page is physically removed and replaced by another in order to access additional vocabulary. In other types of displays—dynamic displays, touching a single symbol allows the student to access multiple overlays automatically. Clearly, the differences between these two types of displays include not just the access to vocabulary, but the distinct demands they make on the user's memory skills.
Other decisions about the device itself include the number of symbols available to the individual at a single time or available in total. A related issue is the size of the symbols displayed on the device at one time. Clearly, within a finite area, the size of an individual symbol and the number of symbols that can be displayed at a single time will be inversely related. The individual's visual and motor skills also must be considered in determining the best symbol x number x size displays.
Bottom Line: Selecting communication devices is not an "either or" decision. People communicate in a variety of ways and, therefore, one device will not meet the person's needs in all situations.