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Choosing an AAC system

AAC devices and systems:

The main categories of AAC

The following are the main categories of AAC. They do not represent the entire range of communication modes in use. This list focuses only on systems that require the child to be an intentional communicator and understand symbols. (See Assessing intentionality, and the understanding of means-end, causality and symbols.) It does not include the myriad other ways in which a child communicates intentionally or unintentionally, such as facial expressions, body position, muscle tone, vocalizations, etc.

  • Graphical communication boards have no or low technology requirements, and utilize pictures, drawings, abstract symbols and/or text as symbols. Examples are communication books, wallets or vests that are referenced by pointing, eye gaze, touching, or scanning that is activated through switches or by indicating to an adult. The symbols on a graphical system may be represented visually, auditorily and/or tactually. These systems tend to be relatively inexpensive and are often homemade.

    A disadvantage of these types of graphical systems, however, is the fact that the partner has to pay attention to the communication board when the child is using it, and not to the child; likewise, the child has to look at the board, too, instead of the partner's face. In addition, the child must use another method to obtain the attention of someone who is not close by and attending. (See Mulitmodal communication.) Adults may also have to learn the symbol system being used.

    Eye gaze techniques are one form of accessing a low or no-technology AAC system. They can be used either to indicate real objects directly, or symbols on a communication board. (See Eye gaze techniques.) They are typically used by children with severe motor disabilities. The main advantage of eye gaze techniques over other methods is speed and efficiency of communication. One of heir greatest disadvantages is that they require substantial effort from the partner to decipher exactly at what the child is looking (Goossens’, 1989; Goossens’ & Crain, 1987). (See Conversational control vs. conversational efficiency.)

  • Voice Output Communication Aids (VOCAs) are also graphical systems, but, unlike communication boards, are high technology devices that output speech. VOCA typically refers to a dedicated electronic speech apparatus, but, for the purposes of this resource guide, computers are referred to under this category since they can also be used as speech output devices. (Even cassette tape recorders can, in some instances, accomplish the same goals as a VOCA.)

    VOCAs range considerably in their flexibility, from a single message VOCA to a sophisticated VOCA with a lot of memory and the ability to store a virtually unlimited number of messages. Vocabulary must be programmed into a VOCA, which may be done at least partially at the manufacturer’s or entirely by the purchaser.

  • Sign language consists of consistent finger and/or hand movements, and may include conventional (e.g. American Sign Language) and idiosyncratic sign languages (e.g. signs that the child has made up which are understood by family members).

  • Gestures are physical movements that are grosser than signs, utilizing entire arm or body movements. Although often a child’s gesturing is self-developed, there are conventional gesturing systems which can be formally taught.

  • Speech is considered to be spoken words that are comprehensible to at least one other person.

  • Vocalizations are sounds produced by the throat and mouth that are not words or approximations of words, but are able to be used for communication consistently and reliably.

  • Concrete objects are tangible objects which are used as symbols for other objects or activities. They may be whole, miniature or partial objects, and are indicated by being pointed to, reached for, touched or held.

Help me—and everyone who reads this site—by mailing your suggestions, criticisms and personal experiences to Ruth Ballinger at yaack@iname.com


Home Page for YaacK, A Resource Guide for AAC Connecting Young Kids

Table of Contents for YaacK: AAC Connecting Young Kids
Choosing an AAC system
AAC devices and systems
The main categories of AAC

Aided vs. unaided AAC systems

An aided AAC system is one that utilizes an external device. Examples are voice output communication devices (VOCAs), computers and communication boards. Unaided systems are those which are independent of a device, such as speech, vocalization, gestures or sign language. There are advantages and disadvantages to both types of systems.

  Aided systems Unaided systems
  • Communication boards
  • VOCAs
  • concrete objects
  • computers
  • Sign language
  • gestures
  • vocalization
  • speech
  •   Aided systems Unaided systems
  • Flexibility.

    Devices used in aided systems are highly flexible and can be designed to take advantage of a child’s strengths and skills, and to compensate for disabilities. They can be accessed in a variety of ways, their output can be visual or auditory, and they can be used with different symbol systems and vocabulary organizational strategies. In particular, they are excellent for children who have severe motor impairments, since they can be switch-activated. (See Communication boards and VOCAs and Direct selection and scanning techniques.)

  • Use of recognition memory.

    In general, aided systems utilize recognition memory (the child is presented with several message choices and merely has to choose the correct one), as opposed to recall memory (the child has to remember how to produce a message with no external cues). Recognition memory is considered cognitively easier than recall memory. Thus, aided systems are beginning to be used more and more with children who have cognitive impairments, even though they may be capable of sign language (Iacono & Duncum, 1995; Iacono, Mirenda & Beukelman, 1993).

  • Nontransience.

    Aided systems are usually nontransient, that is their messages are continually accessible. This means a child can examine them visually or tactually for as long as necessary. \The exceptions are auditory-based aided systems for children with visual impairments.

  • Use of different sensory modes.

    The device can present the child with message choices in any of the five sensory modes. This makes aided systems good for children with sensory impairments, as well as for children who manifest specific sensory learning styles.

  • Capable of speech output.

    Among aided systems, VOCAs represent a new class of AAC. A device with voice output has the advantage of being readily understood by others, as well as providing the child with immediate feedback regarding what message was actually transmitted. This helps the child montior his or her own communication and self-correct as necessary. Moreover, some children seem to prefer using VOCAs to sign language (Iacono & Duncum, 1995; Soto, Belfiore, Schlosser, & Haynes, 1993).

  • Convenience.

    Unaided systems do not depend on anything external. Thus, the child is never without this mode of communication. It is not subject to breakage, loss or lack of availability.

  • Unlimited vocabulary potential.

    A child’s vocabulary depends only on what he or she is capable of learning and is not limited by the characteristics of the device or what someone else has programmed in.

  • Speed.

    All things being equal, unaided techniques have the potential to generate communication at faster speeds.

  • Cost.

    Unaided systems do not have to be purchased or constructed.

  •   Aided systems Unaided systems
  • Inconvenience.

    Aided systems are less convenient. Portability is a big issue since they have to be carried or mounted on wheelchairs.

  • Cost (in terms of money and time).

    The devices must be constructed or purchased, and are subject to weather, breakage and loss. Their content (i.e. messages and vocabulary) is limited to what the device is capable of holding, and to what is programmed or added in by an adult. All in all, the user is highly dependent on the device itself, as well as the adults who are maintaining the device.

  • Lack of initimacy.

    In addition, some people feel that interlarding a device in a social interaction reduces the feeling of closeness and intimacy.

  • Recall memory.

    Unaided systems depend on recall and not recognition memory. The child has to independently remember how to communicate a particular message. This considered more difficult than being able to choose correctly from a set of messages presented on a device (Iacono & Duncum, 1995).

  • Transience.

    Unaided systems are more transient than aided ones. Speech, for example, lasts only as long as it takes to say the words. Sign language is considered a little less transient since a sign can be made visible for a period of time. Still, in order for the next sign to be made, the previous one is no longer available.

  • Motor requirements.

    Unaided systems necessitate specific motor abilities. Speech demands sophisticated oral-motor skills, and sign language requires fine and gross motor skills. Gestures and vocalization are less demanding, but still require distinct motor abilities. Children who do not have these capabilties are not candidates for these modes of communication.

  • Help me—and everyone who reads this site—by mailing your suggestions, criticisms and personal experiences to Ruth Ballinger at yaack@iname.com
    Traditionally, if a child has the requisite motor skills, practitioners have recommended that an unaided system be used. Sign language, for example, has been very widely used among children diagnosed with Down Syndrome or autism. More recently, however, researchers have been looking at the effects of learning style, specific cognitive/memory skills, and the role of speech feedback (i.e. voice output of computers and VOCAs) in successful AAC outcomes. This has resulted in larger numbers of motorically capable children being equipped with aided AAC, and, in particular, VOCAs (Romski, Mirenda, & Schuler, 1988).

    In addition, it is highly recommended that a child be taught at least one unaided system, even if only for emergency purposes. The reason for this is that aided systems can be lost, stolen or otherwise unavailable. Lack of availability is one of the most common reasons for lack of use of AAC cited by adult AAC users (Murphy, Markova, Collins, & Moodie, 1996). Unless the child has an alternative mode, he or she may be without the means to communicate for a long period of time. (See Multimodal communication.)

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    Choosing an AAC system
    AAC devices and systems

    Issues with different AAC devices and systems

    Here are some of the many issues that need to be considered in the selection of an AAC device or system. Some of the answers will be inherent to the device or system itself, others have to come from the manufacturer of the device. (See Finding answers to specific AAC questions.)

    • If a device uses batteries, how long will the batteries last before needing to be recharged?
      A dead battery without a replacement could leave a child without his or her primary means of communication.

    • How reliable is the device?
      Users are more likely to encounter breakdowns with technology-dependent devices than with technology-independent devices.

    • How easily is the device repaired?
      Sometimes high tech devices like voice output communication aids (VOCAs) and computers take weeks to be fixed.

    • How easy is it to make, program, add to, modify or update the device?
      High technology devices, for example, must be programmed. Many graphical devices, both high and low technology, require overlays or pages to be constructed. Given the number of activities—and, therefore, messages—in which the child may be involved in at home, at school and in the community, updating can require a substantial amount of work.

    • What is the quality of the speech output of a VOCA? Can it generate different voices, such as a female’s or a child’s?
      Not only is it crucial that partners be able to understand the speech output of the device, but children are often very sensitive to the quality and type of voice that is being used to represent themselves. The wrong voice could mean the child’s refusal to use the device, and the adults involved would probably never know why the device was rejected (Bizot, 1998).

    • How portable is the device or system? Can it mount on a wheelchair? Can a young child handle it independently?
      Keep in mind that children should be able to communicate at all times, even while walking or otherwise moving from place to place, playing, riding in the car, etc. Children are also small and may have difficulty handling a large or heavy device whether they have physical disabilities or not. This underscores the importance of developing a multimodal AAC program, in which different AAC devices or systems are used in different circumstances.

    • How sturdy is the device or system?
      Children can be very hard on equipment, including AAC devices.

    • How expensive is the device?
      Expense must be looked at in terms of both money and time. High technology devices can cost thousands, while low technology ones can often be homemade. Yet, the time required to construct all the overlays or vocabulary pages necessary for many different activities in different environments may be so great that the high tech device becomes more cost effective. In addition, it is important to consider how difficult it would be to replace a device if it were lost, stolen or irreparably broken.

    • Can the device accommodate direct selection or scanning as needed?
      Direct selection is when the child is able to directly indicate a message, for example, by pushing a button, pointing or looking at a selection. When a child is unable to use direct selection, message items must be presented to the child sequentially until the child indicates a choice, called scanning. (See Direct selection and scanning techniques.)

    • Can the system be used independently, or does it require the assistance of a partner?
      A system is independently used if the child is able to produce messages without adult help. For example, if the child directly selects the message, or is able to activate and interrupt an electronic scanner then he or she does not require the help of an adult. A system requires the assistance of a partner if the partner is in control of scanning and awaits a signal from the child indicating message choice. Examples of this are if the partner recites the available choices (auditory scanning), or points from one picture to another on a picture board (visual scanning).

    • Can the system be used over distances? Can it be used if the partner is not looking?
      A picture board or sign language necessitates the partner being close enough to see the picture or sign that is being indicated. An eye gaze system is even more demanding, and requires that the partner be positioned so that he or she is able to tell at what the child is looking. On the other hand, a child who can vocalize, use speech, use a VOCA, clap loudly, etc. is able to get the attention of a partner some distance away who is not looking at or paying attention to the child.

    • Does the system provide feedback (i.e. does it let the child know whether the right selection was made or not)?
      Many VOCAs offer the user several kinds of feedback; for example, when a message button is pushed a light may go on, a beep may be heard, and, of course, the message is spoken aloud. All this informs the child that a button was pushed successfully, and what the message on the button was. On the other hand, if a child is pointing at a picture on a picture board, he or she may not know whether or not the correct picture is being indicated until the partner responds. Feedback allows the child to self-correct independently when necessary.

    • How rapidly can communication occur?
      The speed of communication play a large role in conversational quality. Interactions between AAC users and non-users tend to be imbalanced, with non-users dominating conversations, and users primarily in the role of respondant. Studies have shown that one of the main stumbling blocks to equalizing their standing is the speed with which the AAC user can converse. (See Conversational control vs. conversational efficiency.) One way a child may be able to increase conversational speed is by utilizing more than one mode of communication at the same time, for example using speech and gestures whenever possible, relying on a VOCA only as necessary. (See Multimodal communication.)

    • How difficult is it for the child to learn how to operate/use the device? How difficult is it to learn the symbol system?
      Often there is a trade-off between ease of learning and system flexibility for both devices and symbol systems. For example, a VOCA with only three buttons may be very easy to figure out, but it offers limited opportunity for growth. Among symbols, pointing to tangible objects may be easy to learn, but is less flexible and convenient than graphic symbols.

    • How much vocabulary can be made available at one time?
      For example, a computer-based system may be able to store thousands of messages, or a picture board can be made with many pages. On the other hand, a system based on tangible objects will be highly limited due to the size of the objects.

    • How comprehensible is the system to partners?
      VOCAs, for example, output regular speech, but sign language or other symbol systems can be like a foreign language and must be learned by partners.

    • How viable is the system in different kinds of weather and at various times of day?
      It is obvious that rain and darkness can be issues, but computer screens and LCD screens can be difficult to read in bright sunlight too.

    • Can the system accomplish other activities besides AAC? In particular, can the system accommodate writing as well?
      A computer, for example, is very flexible in this regard (Vanderheiden, 1984.) For many children, a writing device is essential.

    • Is there capacity within the system for a child to grow and develop, without it being too complicated for the child to use now, or too expensive?
      In selecting a system, it is necessary to ensure that the child is capable of using it effectively right now, but also that there is room to accommodate advancement. The cost of the system comes into play, too, since systems, electronic ones in particular, are often not expected to last forever. Regarding VOCAs, one rule of thumb is to expect the device to last approximately three years for a child (Bizot, 1998).

    Help me—and everyone who reads this site—by mailing your suggestions, criticisms and personal experiences to Ruth Ballinger at yaack@iname.com


    Home Page for YaacK, A Resource Guide for AAC Connecting Young Kids

    Table of Contents for YaacK: AAC Connecting Young Kids
    Choosing an AAC system
    AAC devices and systems

    Issues with symbol systems

    A symbol is anything that represents something else. Symbols are useful because they allow us to refer to objects and events that are not currently present, or are abstract. A child who is pre-symbolic points at, looks at, gestures towards or otherwise refers to what is present and happening in the here and now. (See Assessing intentionality, and the understanding of means-end, causality and symbols and The first goal: Intentional communication.) Symbol systems include speech, sign languages, formal gesturing, and graphical systems (i.e. picture-, drawing- or text-based systems).

    The type of symbol system is somewhat determined by the choice of AAC. For example, speech encompasses English and other languages, sign language may be American or some other type, a graphical system may use pictures or the alphabet. (See The main categories of AAC.) Once the broad choices have been made, it is necessary to select the specific symbol systems to be used with each type of AAC. Although there are different types of sign language and gesturing systems from which to choose, discussions regarding symbol system selection typically refer to those used with communication boards, voice output communication aids (VOCAs), computers, and other graphical systems because the options are very diverse.

    The selection of a symbol system is important and individualistic. It cannot be decided by age, cognitive ability or developmental level of the child, although these do influence the decision. A predominant physical issue that impacts the choice of a symbol system is whether the child has a sensory impairment, which may affect his or her ability to perceive and process certain types of symbols. Children with visual impairments may require tactile or auditory symbols alone or in conjunction with enhanced visual symbols. (See Children with sensory disabilities.)

    In addition, it is important to consider whether the persons with whom the child will be communicating already know a specific symbol system. Choosing an already familiar symbol system means that teachers or family members do not have to learn a new one, and may have had some experience in teaching it. On the other hand, it is important to make sure that a particular symbol system is not being recommended simply due to someone’s desire not to have to learn a new system, or to lack of information about other systems (Romich & Zangari, 1989). (See Teaching symbols.)

    Sometimes a child will initially be taught one symbol system and then move on to a more abstract system that allows for increased sophistication of messages and speed of production. Studies have shown that, in general, the more concrete and real-looking the symbol, the easier it is learn to use, although the less flexible it is. For example, focusing on nouns, the order from easiest to hardest to learn among the following symbol systems is: objects, color photographs, black-and-white photographs, miniature objects (i.e. the identical object but on a smaller scale), black-and-white line symbols (including Picsyms, Self-Talk, Picture Communication symbols and rebuses), Blissymbols, and, finally, written words. (Beukelman & Mirenda, 1992; Reichle, York, & Sigafoos, 1991). A child who is a pre-intentional communicator, for example, may have to start out learning with concrete objects, and then move on to a more abstract and less cumbersome system. See Start with objects as symbols.)


    Help me—and everyone who reads this site—by mailing your suggestions, criticisms and personal experiences to Ruth Ballinger at yaack@iname.com

    • "AAC Symbol System References" at www.asel.udel.edu/at-online/technology/aac/symbols.html. (Note that this site is currently undergoing renovation and is not available.)

      The following books include comprehensive descriptions of different symbol systems.

    • Beukelman, D. R., & Mirenda, P. (1992). Augmentative and alternative communication management of severe communication disorders in children and adults. Baltimore, MD: Paul H. Brookes.

    • Reichle, J., York, J., & Sigafoos, J. (1991). Implementing augmentative and alternative communication. Baltimore, MD: Paul H. Brookes.

    • Silverman, F. H. (1980). Communication for the speechless (3rd ed.). Needham Heights, MA: Allyn and Bacon.

    Home Page for YaacK, A Resource Guide for AAC Connecting Young Kids

    Table of Contents for YaacK: AAC Connecting Young Kids
    Choosing an AAC system
    AAC devices and systems
    Issues with symbol systems

    Minspeak vs. Dynamic Display

    Related to the selection of a symbol system is its organization. The organization of symbols is very important because it establishes how a child locates a particular message, and, consequently, affects the speed (how long it takes) and efficiency (how many movements are required) to ouput a message. Currently among voice output communication aids (VOCAs), there are two predominant symbol organizational systems, Minspeak, also known as Semantic Compaction, which is associated with the Prentke-Romich Co. (www.prentrom.com), and Dynamic Display Pictograph technology, which is associated with Sentient Systems (www.sentient-sys.com). Both are symbol organizational systems used with sophisticated voice output communication aids (VOCAs) that allow the user to quickly locate the desired message among all the available messages.

    In simplest terms, Minspeak uses a single overlay in which a number of picture-covered buttons are located. By pressing a button or combinations of buttons, the desired message is activated. The pictures themselves are logically selected to act as cues to remind the user of the underlying message(s). One picture can represent more than one word or concept. For example, a picture of an apple can represent an apple, food in general, or red objects. If the user wants to say a certain food, then the apple is selected to represent food, followed by at least one other button to, then, indicate the specific food.

    In contrast, dynamic display systems are organized on a hierarchical basis, with each level of pictures increasing in specificity. Pressing a picture-button automatically displays only the set of pictures (i.e. categories or messages) that are under the category of the previous button. The first level of pictures, therefore, represent the largest themes. Pressing one of these picture-buttons automatically reveals the next logical set of pictures representing items in that theme. In this manner the user navigates down through automatically-appearing menus until the desired message is found. For example, pressing the picture-button that represents food may bring up a screen with pictures that represent breakfast foods, snacks, lunch food, etc. Pressing one of these buttons would then bring up the specific foods in that category.

    Today, the differences between Minspeak and DDP have lessened, in particular since the introduction of a device, the Vanguard by Prentke-Romich Co., that utilizes Minspeak in a DDP format (P. McNairn, personal communication, March 1, 1999).


    Home Page for YaacK, A Resource Guide for AAC Connecting Young Kids

    Table of Contents for YaacK: AAC Connecting Young Kids
    Choosing an AAC system
    AAC devices and systems

    Facilitated Communication

    Facilitated communication is a technique of AAC in which the adult acts as a direct intermediary for the child in communicating. In other words, the child guides the adult who then writes, types or uses an AAC device for the child. One example would be the child’s hand holding and guiding a partner’s hand as it types out a message on a computer, or points to pictures on a communication board. Training of the partner is essential since the partner must make sure that it is the child who is providing the direction, and not the adult.

    There has been a substantial amount of controversy regarding facilitated communication. The main dispute surrounds the extent to which the resulting messages are truly intended by the child, as opposed to subconsciously composed by the adult. The following articles, all from the August, 1994 issue of Mental Retardation provide an overview of the issues involved. They represent an attempt to present both sides of the facilitated communication debate.

    • Levine, K., Shane, H. C., & Wharton, R. H. (1994). What if…: A plea to professionals to consider the risk-benefit ratio of facilitated communication. Mental Retardation, 32, 300-304.

    • Ferguson, D.L., & Horner, R. H. (1994). Negotiating the facilitated communication maze. Mental Retardation, 32, 305-307.

    • Goode, D. (1994). Defining facilitated communicaiton in and out of existence: Role of science in the facilitated communication controversy. Mental Retardation, 32, 307-311.

    • Halle, J. W. (1994). A dispassionate (if that’s possible) observer’s perspective. Mental Retardation, 32, 311-314.

    • Hitzing, W. (1994). Reply to Levine et al.’s "Plea to professionals." Mental Retardation, 32, 314-317.

      Help me—and everyone who reads this site—by mailing your suggestions, criticisms and personal experiences to Ruth Ballinger at yaack@iname.com

    • Levine, K., Shane, H. C., & Wharton, R. H. (1994). Response to commentaries on risks of facilitated communication. Mental Retardation, 32, 317-318.


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