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[[Traumatic brain injury]] (TBI) results in severe motor speech disorders—particularly [[dysarthria]], in roughly a third of cases.<ref>Sarno M, Buonaguvro A, Levita E (1986). Characteristics of verbal impairment in closed head injured patients. Archives of Physical Medicine and Rehabilitation, 67, 400-405</ref> Depending on the stage of recovery, AAC intervention may involve the establishment of consistent responses, the facilitation of reliable yes/no responses and the ability to express basic needs and to answer questions, and later, if necessary, more longer term AAC, including high-tech systems. Individuals who do not recover natural speech to a degree sufficient to meet their communication needs typically suffer from severe impairments related to cognition.<ref name="Fager s 2007"/>. Memory impairments and difficulties with new learning may influence AAC choices, since individuals with TBI may have difficulty recalling where information has been stored. As a result, overlearned techniques such as spelling may be more effective than AAC systems which require navigation through multiple pages to access information.<ref name="Fager s 2007">Fager S, Doyle M, Karantounis R.(2007) "Traumatic Brain Injury," in Beukelman D, Garrett K, Yorkston K (eds) Augmentative Communication Strategies for Adults with Acute or Chronic Medical Conditions. Baltimore, Maryland: Paul H Brooks Publishing</ref> Problems with initiation and generalization of new skills may influence the extent to which the AAC system is used in daily life; thus the training and involvement of communication partners is generally necessary.<ref name="Fager s 2007"/>
[[Traumatic brain injury]] (TBI) results in severe motor speech disorders—particularly [[dysarthria]], in roughly a third of cases.<ref>Sarno M, Buonaguvro A, Levita E (1986). Characteristics of verbal impairment in closed head injured patients. Archives of Physical Medicine and Rehabilitation, 67, 400-405</ref> Depending on the stage of recovery, AAC intervention may involve the establishment of consistent responses, the facilitation of reliable yes/no responses and the ability to express basic needs and to answer questions, and later, if necessary, more longer term AAC, including high-tech systems. Individuals who do not recover natural speech to a degree sufficient to meet their communication needs typically suffer from severe impairments related to cognition.<ref name="Fager s 2007"/>. Memory impairments and difficulties with new learning may influence AAC choices, since individuals with TBI may have difficulty recalling where information has been stored. As a result, overlearned techniques such as spelling may be more effective than AAC systems which require navigation through multiple pages to access information.<ref name="Fager s 2007">Fager S, Doyle M, Karantounis R.(2007) "Traumatic Brain Injury," in Beukelman D, Garrett K, Yorkston K (eds) Augmentative Communication Strategies for Adults with Acute or Chronic Medical Conditions. Baltimore, Maryland: Paul H Brooks Publishing</ref> Problems with initiation and generalization of new skills may influence the extent to which the AAC system is used in daily life; thus the training and involvement of communication partners is generally necessary.<ref name="Fager s 2007"/>

==Early language learning using AAC==

Generally, children depending on a AAC system for the development of language do experience both expressive and receptive language impairments, however it is important to take into account that using the AAC device to support language development is not necessarily a contributing factor to the delays.<ref name="Beukelman">{{cite book|last=Beukelman|first=D.R.|coauthors=Mirenda|others=P.|title=Augmentative and Alternative Communication: Supporting Children and Adults with Compex Communication Needs|publisher=Paul H. Brookes|location=Baltimore|date=2005|edition=Third}}</ref> Delays that are apparent in AAC users tend to be the result of factors relating to physical and cognitive limitations associated with the individual’s overall condition.<ref name="Beukelman" />

The following intervention strategies have been commonly used to support language learning in AAC device users:

'''Symbols and language'''
A wide variety exists in terms of available AAC symbol sets and currently no one symbol set has been proven to be effective in facilitating language development.<ref name="Beukelman" /> Researchers do however note the importance of using symbols that allow representation of grammatical markers that indicate tense, quantity and possession, as many AAC devices tend to be simplified in order to reduce the cognitive load of the communicative task on the user.<ref name="Beukelman" />

'''Organizational strategies'''
Several organizational strategies are used in order to promote efficient and effective communication to encourage language learning. Two main categories exist: grid displays and visual scene displays

Additional intervention methods implemented with AAC users such as the '''Instructional Approaches''' and the '''Interactive Models''' focus on enhancing specific aspects of receptive and/or expressive language development.<ref name="Beukelman" />

The '''Structured Method''' is a direct instructional strategy based on both experimental and applied behavior analysis and is implemented by an interventionist or a computer on one learner at a time. Ideally, the format of a structured strategy involves a stimulus, a prompt, a response by the learner and a reinforcer.<ref name="Beukelman" /> It may be used to teach receptive and expressive labeling, and morphemic and syntactic language forms using AAC techniques,<ref>Harris, L., Doyle, E.S., & Haaf, R. (1996) : Language treatment approcach for users of AC: Experimental single-subject investigation. ''Augmentative and Alternative Communication, 12,'' 230-243</ref> as well as a supplementary tool for other intervention methods.<ref name="Beukelman" />

The Interactive Model refers to the training programs used with typically developing children such as the Hanen Early Language Parent Program and the Prelinguistic Milieu Teaching that encourage the involvement of parents in promoting their child’s early speech and language development. Nevertheless, this type of approach could also effectively be used with children who communicate through AAC since the basis of their principles is universal.<ref name="Beukelman" />

In addition, the '''Aided Language Stimulation''' and the '''System for Augmenting Language''', which are intended to teach comprehension and use of graphic symbols for AAC applications in a naturalistic context, have proven to be effective methods in language acquisition through a less structured training intervention.<ref name="Beukelman" />


===Effect on speech development===
===Effect on speech development===

Revision as of 20:47, 7 September 2009

Augmentative and alternative communication (AAC) is communication for those with impairments or restrictions on the production or comprehension of spoken or written language.[1]

Definition

Augmentative and alternative communication is any method that supplements or replaces speech and writing when these are temporarily or permanently impaired and inadequate to meet all or some of a person's communication needs.[1] Use of AAC involves selecting messages or codes from a set of possibilities. The user can use these elements alone or in combination in order to communicate a variety of messages.[2] AAC may be unaided, or aided, involving high and low technology.

Unaided AAC

Unaided AAC systems are those that do not require any external device for their use, and include facial expression, vocalizations, gestures, and signed languages and systems.[3][4] Informal vocalizations and gestures such as body movements, facial expressions, and body postures are part of natural communication, and such signals may be used by those to profound disabilities.[5] More formalized gestural codes exist that lack a base in a naturally occurring language; an example is the Amer-Ind code based on American Indian Hand Talk, and has been used with children with severe-profound disabilities, and adults with a variety of diagnoses including dementia, aphasia and dysarthria.[6] </ref> The benefits of such gestures and pantomime are that they are always available to the user, usually understood by the listener, and are efficient means of communicating.[7]

As forms of AAC, manual signs, such as manually coded language (such as Signing Exact English) and signed languages (such as American Sign Language and British Sign Language) have been used alone or in conjunction with speech.[8] Formal gesture and sign systems require adequate memory and fine-motor skills to be able to remember and physically make the signs and gestures, as well as for communication partners to understand the symbols made.[9][10] Manual signs in particular are less transparent in meaning than gestural codes and require more fine-motor coordination to execute.[11] In sign systems, the symbols are hand signals which can be iconic (they resemble the word they represent) or more abstract.[7] With signs, the communication partners need to understand the signs for successful communication. As well, the user’s ability to control gross and fine motor movements needs to be considered with these approaches.[7]

Aided AAC

An AAC aid is any "device, either electronic or non-electronic, that is used to transmit or receive messages",[12] such as communication books or voice output devices using symbols such as photographs, line drawings, words or letters.[4] Since the skills, areas of difficulty and communication requirements of AAC users vary greatly, and so an equally diverse range of communication aids and devices exists to meet these demands.

Low-tech

Low tech AAC communication using an eye gaze communication board

Low-tech communication aids are defined as those that do not need batteries, electricity or electronics to meet the user's communication needs. These are often very simple aids created by placing letters, words, phrases, pictures and/or symbols on a board or in a book, which may be accessed[13] Depending on physical abilities and limitations, users might indicate the appropriate message with a body part, a head or mouth stick or light pointer. Alternatively, they might indicate yes or no as a listener scans through the possible options.[14]

High-tech

High-tech AAC aids are electronic devices that permit the storage and retrieval of messages, with most allowing the user to communicate with others using speech output.[15] Such devices can also be referred to as Speech Generating Devices (SGDs) or Voice Output Communication Aids (VOCAs).[16] High-tech systems can be divided into dedicated devices developed solely for the purpose of communication and AAC, and non-dedicated devices, such as computers, which have been adapted for use as communication tool, but which can also be used for other functions.[15][17] On static display devices, all the symbols are constantly displayed on the device. On dynamic AAC devices, multiple pages of symbols are possible, and thus only a portion of the symbols available are visible at any one time, with the communicator navigating the various pages.[18]

High-tech devices vary in size and weight, as well as the amount of information they can store and the way it is stored.[15] They vary in the user can access their messages, including the use of direct selection of a screen or keyboard with a body part or pointer, adapted mice or joysticks, or indirect selection using switches and scanning. The specific access method will depend on the skills and abilities of the communicator.[15][17] Since electronic devices operate on batteries that need to be frequently changed or charged, and may breakdown, users usually also require access to a low-tech communication system.[13][17]

Symbols

The representation system or symbols used in AAC include gestures, hand signal, photographs, pictures, line drawings, words and letters.[19] The choice of symbol system will depend on the AAC user's abilities; many will use different symbol systems at different times.[citation needed] It is important to consider the individual user’s preference, visual acuity, and visual processing of information when establishing which type of pictures are appropriate for their communication system.[7]

Picture symbols are used with those who cannot read or write. Some picture systems, such as Blissymbols have linguistic characteristics, while others such as the Picture Communication System (PCS) do not.[20] Symbols can be realistic pictures in color or in black and white, or simple line drawings. Some users understand the line drawings better than detailed colorful pictures or vice versa.[7] Symbols can be strictly visual when located on boards or screen displays or they can be tactile such as with the Picture Exchange Communication System (PECS).[7] With this system, the pictures are on cards for the user to move around to form a message. Tangible items can also be part of symbol systems, such as miniature objects representing their real counterpart, or small items as abstract representations.[21]

The user's visual acuity and visual-perceptual discrimination skills will affect the presentation of the symbol system on the AAC device (e.g. determining the size of the graphic symbols or the background-figure contrast).[22]

Both low and high tech devices may use alphabet-based symbols including individual letters, whole words, or parts thereof.[21] Literacy is required for these symbols. In low-tech devices, the communication partner may see the symbols, such as with an alphabet board. In high tech devices such as Voice Output Communication Aids (VOCAs), the device will read the message put together with symbols out loud.[21]

Organization of symbols

Vocabulary organization refers to the way pictures, words, phrases, and sentences are displayed.[23] In an AAC system, symbols must be organized to facilitate efficient and effective communication. This is especially important when the individual has a large number of symbols in an AAC system.[24]

On static systems, symbols are placed in certain fixed positions; the number of symbols that can be included in a fixed display is limited and in order to compensate the device may be set up on multiple levels, or an encoding strategy used, in which a person can express multiple messages by combining one to three (or more) symbols on a fixed display.[25] On a "dynamic display", a computer screen can display linking symbols that, when activated, automatically change the selection set on the screen to a new set of symbols.[25]

Individual pages of a communication book or device may presented into several ways. In grid displays, individual symbols, words, phrases, or pictures are combined in a grid format.[24] The grids may be organized in a variety of ways, including by spoken word order or frequency of usage, for example the Fitzgerald Key organization in which symbols are placed from left to right into categories labelled who, doing, what, where, and when, with frequently used phrases and letters clustered along the top or bottom of the display.[26][27] The use of these displays has been shown to facilitate language and literacy skills in children.[28] Core vocabulary, the words and messages that are communicated most frequently appears on a "main page". A user's fringe vocabulary, including words and messages that are specific to an individual appear on other, pages.[24] Research has shown that both children and adults use a small core vocabulary and a large fringe vocabulary.[29][30]

Large symbols vocabularies may also be organized by category, by grouping people, places, feelings, foods, drinks, and action words together.[24] Research conducted with typically developing children found that this type of organizational strategy is not useful until they reach at least the age of 6 or 7.[31]

Another form of grid organization groups vocabulary according to specific activities.[24] These can include items that are related to an activity (i.e. going grocery shopping) or routines within that activity (i.e. making a list, paying for items at the cash register).[32] Each display contains symbols for the people, places, objects, feelings, actions, and other relevant vocabulary items for a specific activity or routine.

Visual scene displays represent a different method of organizing and presenting symbols. These are depictions of events, people, objects, and related actions in a picture, photograph, or virtual environment representing a situation, place, or specific experience[24][33] They are similar to activity displays, as they contain vocabulary that is associated with specific activities or routines. For example, a photo of a child’s room could be included in the child's AAC system. Objects and events within the photograph could then be used as symbols for communication. For example, the symbol for "play" could be accessed by selecting the toy box, whereas selecting an individual toy would access the name of the toy.[34] Research suggests that visual scene displays are easier for young, typically developing children to learn and use, when compared grid displays.[35][36][37] Symbols can also be presented in a hybrid display, in which both the grid and visual scene displays appear together.[24]

Access

Access to AAC entails a complex interrelationship between the features of the AAC technology, the individual's physical abilities (e.g. motor, sensory, perceptual, cognitive and linguistic skills), and the device users' and their communication partner's abilities to interact.[37] Technological development in direct selection and scanning have dramatically increased access to AAC technologies for individuals with a wide range of communications needs.[37] Some people with severe communication impairments can use their hands to use AAC; others who cannot do so use alternatives such as mouth sticks, head sticks, switches or eye pointing. In this "direct Selection" a selection is made by pointing to the desired symbol using a finger or an alternative pointing technique (i.e., head pointer, eye gaze, joystick, mouse). In order to accommodate motor control difficulties some users use alternative activation strategies; for example in "timed activation" must maintain contact with the aid for a predetermined period of time for the selection to be recognized by the system. With the "release activation", the selection of the item is only made when the person releases contact from the display.[25] Direct access is generally the first choice for AAC users as it is cognitively easier and faster to use.[22]

Whenever AAC users are unable to choose items directly, usually due to lack of motor control, they use an indirect selection technique called scanning, whereby items displayed for selection are scanned visually by an indicator (such as small lights, highlighting, or contrasting borders) or auditorially by the communication partner or by the device. When the desired message is reached, the AAC user indicates his or her choice by using an alternative selection technique (i.e. switch access, head nodding) to confirm the choice.[25] Several different scanning patterns are available: in "Circular scanning", the least complex pattern, the items are displayed in a circle and then scanned them one at a time, until the user selects a desired item. As it the easiest to understand, it is often introduced first to children or beginning AAC users.[25] In "Linear scanning", items are organized in rows and are scanned one at a time until a choice is made. Although more demanding than circular scanning, it is still easy to learn.[25] Finally, in "group-item scanning" first a group of items is selected; this group is then scanned, eliminating options until a final selection is made. One of the most common group-item strategies is row-column scanning in which rows of items are first scanned and selected, and the items in the resulting row scanned one at a time until a choice is made.[25]

There are three main selection control techniques in scanning: in "Automatic scanning", the scan proceeds at a pre-determined speed and pattern; when the desired item or group is reached the individual makes the choice using a control interface such as switch.[25] In inverse scanning, the switch is held down to advance the scan, and released to choose the desired item. In "step scanning", the AAC user activates one switch to move the indicator through the items, and another switch to select the item.[25]

Rate enhancement strategies

Augmentative and alternative communication is generally slower than speech.[38] Rate enhancement strategies increase the user's rate of output, and as a result enhance the efficiency of communication. There are two main options for increasing the rate of communication for AAC devices: encoding and prediction.[38] Encoding is a technique permitting an AAC user to produce an entire word, sentence or phrase using only one or two activations of their AAC system.[38] In "Iconic encoding" sequences of icons (picture symbols) are combined to produce words or phrases.[39] In numeric, alpha-numeric, and letter encoding (also known as Abbreviation-Expansion), words and sentences are coded as sequences of letters and numbers. For example, typing "HH" or "G1" (for Greeting 1) may retrieve "Hello, how are you?".[39]

Keyboard text-to-speech generating device

Prediction is a rate enhancement strategy in which the AAC device attempt to predict the letter, word or phrase being written by the user. The user can then select the correct prediction without needing to write the entire word. Word prediction software may determine the choices to be offered based on their frequency in language, association with other words, past choices of the user, or grammatical suitability.[38][39][40]

Team

A comprehensive evaluation of a user's unique abilities and requirements is necessary in order to implement appropriate intervention and match the user with the most appropriate AAC device. AAC evaluations are conducted by specialized multidisciplinary teams consisting of a speech-language pathologist, occupational therapist, physiotherapist, social worker and a physician.[22][41] The assessment team conducts interviews with the user, family members, caregivers and/or teachers in order to obtain additional information about the user's behaviour and skills in different settings. The team also assesses the user's motor abilities, communication skills, cognition and vision.[41]

During the intervention process, the occupational therapist assists with the positioning and seating adaptations so that the individual can have the best access to the AAC system. For example, an individual with spastic arm movements might need a key guard on top of a keyboard or touch screen to minimize the chance of selecting a wrong button. The physiotherapist works on motor development training. The speech-language pathologist's role is to teach the user and their communication partners how to use the AAC device, encouraging the use of natural speech when possible. In selecting and adapting the AAC device for the user's individual needs, the speech-language pathologist's goal is to ensure that the AAC device can be used in different contexts and with different communication partners.[22]

Specific groups of AAC users

Cerebral palsy

Cerebral palsy is a developmental neuromotor disorder that is the result of a non-progressive abnormality of the developing brain.[22] The motor deficits associated with cerebral palsy (CP) cause speech disorders in 31% to 88% of CP patients, and may required AAC support for communication.[22] Gross and fine motor challenges may be of particular concern in accessing the AAC device.[22]

Simple switch-operated speech generating device

This population often faces an additional communication challenge, in which family members and peers tend to direct and control conversations. Consequently, children with CP may not use their AAC aids as often. This has the potential to lead to delays or failure to develop the full range of communication skills such as initiating or taking the lead in conversation, using complex syntax, asking questions, making commands, or adding new information.[42][43] Training of communication partners may prevent the development of learned helplessness in children with CP that can result from being passive communicators,[22] and training of the AAC user about howhow to communicate effectively with others, to control their environment through communication, and using their AAC system to make choices, decisions and mistakes.[22]

Intellectual impairment

Prior to the mid 1980s, individuals with Intellectual impairment (also known as mental retardation) were often not provided with AAC symptoms as it was believed that they did not demonstrate prerequisite skills for AAC or because of the notion that AAC would interfere with speech development.[44] Both notions have been disabused,[45] and the use of AAC devices for this population has been substantiated in the research literature. From simple single-switch VOCAs to dynamic displays with visual scenes, studies have shown that appropriate use of AAC devices can modify classroom, home, and social environments for children and adults with intellectual impairments to increase participation,[44] make choices,[46] enhance communication skills,[47][48][49] and even influence the perceptions and stereotypes of communication partners.[44]

A great diversity of diagnoses result in intellectual impairments, that result in varying degrees of communication impairments. AAC interventions in this population 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.[50]

While most individuals with intellectual disabilities do not have concomitant behavioural problems, it is known that behavioural problems are typically more prevalent in this population than others.[51] In the past, strategies to "manage" behavioural problems included incarceration, medication and aversive behaviour modification techniques.[50] Since the mid 1980s, greater emphasis has been placed on teaching functional communication skills to individuals as an alternative to "acting out" for the purpose of exerting independence, taking control, or informing preferences. This paradigm shift in the management of behavioural problems for this population has placed new emphasis on AAC because many of these individuals do not have functional speech for communication.[50]

Individuals with intellectual impairments face challenges in developing communication skills, including problems with generalization (the transfer of learned skills into daily activities).[50] They also often lack naturally occurring communication opportunities and responsive communicators with whom they can interact in the home, school and community environments.[24] As a result, AAC intervention for this population emphasizes partner training as well as opportunities for integrated, natural communication.[24]

Autism

Autism is a disorder distinguished by qualitative impairments in communication and social interactions and typically have more difficulty acquiring expressive skills.[52][53] Children with autism have been found to have strong visual-processing skills, making them good candidates for an AAC device.[54]

Speech generating device

AAC intervention in this population is directed towards the linguistic and social abilities of the child.[24] including providing the child with a concrete means of communication, as well as facilitating the development of interaction skills.[52][54] Existing functional communication skills, such as joint attention, predict better use of AAC.[54][55]

AAC systems for this population will generally begin with communication boards as well as with object or picture exchanges such as the Picture Exchange Communication System.[52] A 2009 descriptive review provides preliminary evidence that PECS is easily learned by most individuals and provides communication to individuals with little or no functional speech, and some limited positive impact on social communication and challenging behaviours.[56] However, a study that compared the use of a voice-output communication aid (VOCA) to a picture-exchange system found that each were plausible options for children with autism, as the ease and speed of acquisition of both systems was similar among all participants.[57]

Developmental dyspraxia

Developmental dyspraxia is a childhood motor speech disorder involving impairments in the motor control of speech production, typically causing impairments in motor programming and execution.[58] The speech of a child with developmental dyspraxia may be unintelligible to the point that daily communication needs cannot be met and that the child experiences great amounts of frustration. AAC can be a strategy to support communication, with the hope that speech will improve with time and eventually be able to meet daily communication needs. Research indicates that AAC use with this clientele does not impede speech development, and that it facilitate speech development.[50] AAC interventions in this population are made alongside more traditional speech therapy to improve natural speech production.[50]

A wide variety of AAC systems have been used with children with developmental dyspraxia.[59] Manual signs or gestures are the most frequent unaided AAC system introduced to these children, and can include signing unintelligible target phonemes (using fingerspelling) alongside speech. Manual signs have been shown to decrease articulation and speech sequencing errors.[50]

Communication book

Aided systems used with children with developmental dyspraxia typically include communication boards or books using graphic symbols, and voice output devices.[59] While these are portable and tailored to child's communicative needs, they limit the user's ability to communicate to the topics on the board.[60] Voice output devices provide the user with a much greater vocabulary, access to a wider range of topics, and the ability to generate grammatical sentences.[50]

A multimodal approach is often chosen, such that more than one AAC option is introduced to the child. This way, the child is not only given the opportunity to experiment with various aided and unaided AAC systems, but can also take advantage of certain systems that may be better than others in certain contexts.[50]

Visual impairment

High and low tech AAC systems require modification in order to make them accessible to AAC users who are blind or who have visual impairments. Modified visual output that includes large print and/or clear simple graphics can be of benefit to AAC users with some residual vision.[61] Tactile/tangible symbols are textured objects, real objects or parts of real objects that may be included on an AAC device for individuals with visual impairment.[62] Braille is further an example of a tactile/tangible reading and writing system. [citation needed] Tactile/tangible symbols can be used on low or high tech displays and switches.[citation needed]

Auditory symbols are those that produce a meaningful sound when activated, and are thus useful for AAC users who have vision impairments. Morse Code is an example of an auditory symbol system, where long and short tones represent letters, words, and phrases.[citation needed] Some AAC devices that can convert Morse code into text or speech.[citation needed] Speech is another example of an auditory symbol that can be integrated with assistive technology for the blind and visually impaired.[62] Auditory scanning is an access method that utilizes speech with an AAC device. It presents options to the user by pronouncing them out loud and allows the users to select the desired option upon hearing it.[63]

Aphasia

Aphasia is the result of an impairment to the brain’s language centers affecting production, comprehension, or both, and can cause severe, chronic language impairment.[64] Individuals with aphasia can use AAC to communicate using a variety of means, including a combination of speech, gesture, or other devices,[65] which may change over time as needs and skills change.[65]

Static communication device

Those with aphasia may use low-tech AAC interventions such as communication and remnant books, drawing, photography, written words and messages, and written choices.[64] In addition, high-tech AAC devices such as voice output communication aids, keyboards, or pictographic grid displays may be used for communication.[64] Visual scene displays have been used with adults who have chronic, severe aphasia, in which photos of events or people that are meaningful to the individual are used to give context to communicative interactions.[64] Approaches such as "Supported Conversation for Adults with Aphasia" train the communication partners to use resources such as writing key words, providing written choices, drawing, and using items such as photographs and maps to help the individual with aphasia produce and comprehend conversation.[66][67]

Brainstem stroke

Strokes that occur in the brainstem may suffer from profound deficits, including locked-in syndrome, [68] in which cognitive, emotional and linguistic abilities remain intact but all or almost all voluntary motor abilities is lost.[69] Most will need to rely on AAC strategies to communicate, since few recover intelligible speech or functional voice.[70] The AAC strategy used varies depending on the time post-stroke, the residual motor capabilities and individual preference. Eye blinks are frequently used for communication, as vertical and/or horizontal eye movements may be preserved.[69] Low-tech alphabet boards are often introduced immediately in order to provide the individual with basic communication. Listener assisted scanning may be used, in which the alphabet is read out by the communication partner, and AAC user signals the desired letter is reached. When vertical and horizontal eye movements are functional, a transparent alphabet board may be used, in which the AAC user looks at the desired letter and this is acknowledged by the communication partner..[69] These methods can be very slow and require intense concentration, patience and good memory on the part of the communication partner.

Speech generating device accessed using a head mouse

The use of high-tech AAC device with individuals with locked-in syndrome may be difficult due to the problems with voluntary muscle activity, visual focusing, memory, alertness and/or linguistic ability.[69] A voluntary, reliable and easily controlled muscle movement is necessary to access such as a device, though can be the slightest movement of a finger, wrist or chin, a frowning of the forehead or biting.[69] If the patient has good head control, a head mouse activates the computer.[69] Those who do not have stable head movement require extensive practice to control the AAC device accurately. Laser pointers paired with laser-sensing surfaces have been shown to increase the accuracy and consistency of head movements.[70] Examples of assistive hardware and software used with this population include word prediction programs which reduce the effort required to write; speech synthesizer programs which convert written text into speech; or replacing a regular keyboard with an on-screen keyboard layout activated by a switch or head-mouse.[69]

Amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) or Motor Neurone Disease is a progressive condition in which the motor neurones required for movement break down, leading to weakness and eventual paralysis. Approximately 75% of people with ALS are unable to speak by the time of their death.[71] Generally, AAC is necessary when speech intelligibility becomes inconsistent, especially in adverse listening conditions (i.e.: a noisy restaurant).[71] In most cases, this happens when speaking rate drops to 100 words per minute.[72] In the early stages of ALS, AAC may only be necessary to augment natural speech with unfamiliar partners (e.g. using an alphabet board to cue the listener to the first letter of the word being spoken). In the later stages of ALS, AAC often becomes the main communicative method, although familiar conversation partners may still understand specific spoken words.[73] Since ALS is degenerative in nature, the choice of device has to take into account both present and future needs.[71]

Stephen Hawking, physicist, person with ALS and AAC user

The chosen AAC system will depend on severity of speech impairment, functional status, and communication needs in particular environments.[73] These include issues of portability, durability and powered mobility.[73] As cognition and vision are unaffected in ALS, writing and typing systems tend to be the most recommended and preferred devices because they allow unlimited expression.[73] The access to the device depends on the type and severity of the disease. In the spinal form of ALS, the limbs are affected from the onset of the disease. In these cases a high-tech device using a head mouse or eye tracking access may be used.[74] Low-tech systems, such as eye gazing or partner-assisted scanning may be used in situations when electronic devices are unavailable (i.e.: during bathing).[73] In the bulbar form of ALS, speech is affected before the limbs. As a result, handwriting is often the first course of AAC. As the disease progresses and starts affecting hand movement, writing or typing VOCA devices may be optimal, as these require less manual dexterity, while still offering full freedom of expression. In the final stages of the disease, eye gaze and partner-assisted scanning are preferred as they carry the added benefit of promoting social closeness.[73]

Parkinson's disease

Parkinson’s disease is a progressive neurological condition in which initially no speech disorder may be present.[24][75] However, hypokinetic dysarthria may develop later in the disease progression,[72] and some individuals eventually lose all functional speech.[24] Factors affecting AAC use in Parkinson's disease include the motor deficits, and cognitive changes including lack of insight into the extent of their communication difficulties.[24][75][76] Since most individuals with Parkinson's disease are able to communicate using natural speech, AAC devices are generally used to supplement speech.[24] A portable amplifier, for example, increases the volume of a person’s voice and thus intelligibility. In addition the person may be taught to point to the first letter of each word on an alphabet board supplementation; this results in a reduced speech rate and visual information for the listener to compensate for impaired articulation. Entire words can be spelled out if necessary.[24] Since Parkinson's disease is associated with reduced range and speed of movement, a small-sized board may be preferred.[24] High-tech AAC keyboard speech-generating devices are also used; keyguards may be required to prevent accidental keystrokes caused by tremor.[24]

Multiple sclerosis

Dysarthia is the most common communication problem in individuals with multiple sclerosis (MS); significant difficulties with speech and intelligibility are uncommon.[24][77] Individuals with MS vary widely in their motor control capacity and the presence of intention tremor, and methods of access to AAC technology are adapted accordingly. Visual impairments are common in MS, and 35% of people with MS experience optic neuritis as the first symptom. AAC users with visual impairments may require devices that allow auditory scanning systems, large-print text, or synthetic speech feedback that plays back words and letters as they are typed.[24]

Dementia

Dementia is an acquired, chronic, cognitive impairment characterized by deficits in memory and in at least one additional cognitive domain, such as language, visuospatial function, apraxia (movement), judgment or executive functions.[64][78] Its most common form is Alzheimer’s disease.[50] Communication impairments are partly attributed to memory deficits.[78] AAC intervention for individuals with dementia is relatively new.[64] Its goal is to compensate for deficits and to capitalize on the person's strengths, focussing on recognition rather than recall.[50] Low tech devices, such as memory books, including autobiographical information and daily schedules, small wallets with photographs, and communication cards acting as reminders or labels are generally preferred,[50] and several studies have shown positive outcomes in the amount of on-topic conversation and the length of interaction with their use.[79][80][81] In addition, training designed to teach individuals with dementia to use such memory aids, was found to be maintained four months after intervention.[81] High-tech devices with voice output have been found to be less effective: in one study such devices resulted in limited topic elaboration/initiation, reduced output and heightened distraction.[78] AAC is also used to enhance the comprehension of those with dementia. The use of augmented listening strategies, such as identifying topics of conversation with pictures improves the conversational skills of individuals with dementia.[50]

Traumatic brain injury

Traumatic brain injury (TBI) results in severe motor speech disorders—particularly dysarthria, in roughly a third of cases.[82] Depending on the stage of recovery, AAC intervention may involve the establishment of consistent responses, the facilitation of reliable yes/no responses and the ability to express basic needs and to answer questions, and later, if necessary, more longer term AAC, including high-tech systems. Individuals who do not recover natural speech to a degree sufficient to meet their communication needs typically suffer from severe impairments related to cognition.[83]. Memory impairments and difficulties with new learning may influence AAC choices, since individuals with TBI may have difficulty recalling where information has been stored. As a result, overlearned techniques such as spelling may be more effective than AAC systems which require navigation through multiple pages to access information.[83] Problems with initiation and generalization of new skills may influence the extent to which the AAC system is used in daily life; thus the training and involvement of communication partners is generally necessary.[83]

Effect on speech development

Parents of children with developmental disabilities frequently express concern about speech development. In some cases, parents may hesitate to implement an AAC system/device as they worry that the device will become a permanent substitute for speech (ie, the child will no longer have a reason to speak if he/she can communicate using a different system).

A 2008 systematic review found that, in general, AAC interventions do not appear to impede the development of speech, and may result in increased speech production, with modest gains observed.[84] A 2009 descriptive review found inconsistent and unclear data on whether PECS affects speech development; several studies reported an increase in speech, often during later phases, while one noted little or no effect.[56]

Some researchers hypothesize that using an AAC device relieves the pressure of having to speak, allowing the individual to focus on communication; the reduction in psychological stress making speech production easier.[85] Others speculate that, in the case of electronic voice output devices, the device provides a model of spoken output for children with developmental disabilities which may lead to an increase in speech production.[86]

Parents of children who are non-verbal or have limited speech output often state that they'd like their child to use speech as his/her primary mode of communication. When discussing AAC options with a speech-language pathologist, both parents and clinicians must keep in mind that although studies have shown that AAC does not impede speech production, the gains in speech output made by the subjects have been modest,[84] and expectations for the child's speech development should be adjusted accordingly. Further, children requiring AAC present with a wide range of abilities and disabilities, and different diagnoses as well as different developmental progressions are likely to influence the effects of AAC on the development of speech.


Multicultural aspects

Cross cultural differences should be taken into account when assessing and planning for AAC intervention.[87] Ethnic awareness helps professionals determine which AAC system is best suited for their client.[88][89] Providing AAC services requires the input of family, particularly for early intervention. Respecting ethnicity and family beliefs are key to a family-centered and ethnically competent approach.[90] AAC service providers may face challenges due to their lack of information about other cultures, due to families' attitudes about their own involvement in their child's care or their loved one, and culturally specific views about disabilities in general.[citation needed]From the team's perspective, respect and understanding of culturally diversity can help prevent family alienation,[91] contribute to the selection of the right AAC system for the user,[92][93][94] and to the family wanting to continue collaborating with the AAC team.[95]

Professionals must consider the "visibility" of the device.[96] Some cultures do not want the AAC to attract attention to the user; the need for an AAC is a private matter and they will not want to attend training sessions. These priorities may differ considerably from the AAC team's views, but they require consideration to promote cultural respect.[97]

Culturally diverse child rearing practices influence AAC intervention.[98] Accepting a communication aid and being labeled with a disability may be easier for some cultures which promote accessibility.[98] Other cultures may place greater value on hierarchical family structures, politeness, indirect communication, and respect authority figures.[98] Disability may also be viewed with a stigma; thus, folk, spiritual, and natural interventions may be preferred over modern technology.[98] Other cultures may expect an AAC device will immediately reduce the visibility of the disability, while other cultures may prefer not to have an AAC device at all in order to reduce stigma.[99]

When attempting to match the AAC system to the user, professionals consider several factors, including the need for the communication device to help promote self-determination, i.e., the ability to make one's own decisions and choices about one's life.[100][101] Some cultural groups consider a child's independence as a rebellion, and do not believe children should be allowed to have greater control of their own lives.[102] Thus, an AAC device may not be considered necessary if the goal is to increase the user's independence and promote individualism.

Cultural sensitivity may require avoiding stereotyping color and symbols, such as using black to denote "wrong" or "bad" and using culturally specific symbols and colors.[90]

Literacy

Many children who use AAC have difficulties learning to read and write due to a variety of impairments that can affect emergent literacy. Users with motor impairments, such as cerebral palsy or spinal cord injuries, do not tend to experience significant cognitive or learning delays that contribute to difficulty with literacy development.[98] Children with language delays lack the strong foundation for literacy learning, and may then fall behind their typically developing peers in regular classrooms that assume a certain level of language mastery.[103] These language and literacy delays can have far reaching effects as literacy skills facilitate self-expression and social interaction in face-to-face conversation and provide opportunities to participate in home, work, school, and social settings.[104] Furthermore, literacy fosters independence by providing access to educational and vocational opportunities.[105]

Currently, most children who use AAC do not achieve literacy skills beyond a second grade level.[106] Those who grow into functionally literate adults often report having access to abundant reading and writing material at home as well as in school during childhood.[107] Engaging in rich language and literacy experiences before entering school fosters vocabulary development, discourse skills, and phonological awareness, all of which supports successful literacy learning. These experiences are even more valuable for children who use AAC as many experience vocabulary delays, short utterance length, weak syntax, and impaired pragmatic skills.[103]

There is a common misconception that individuals who need AAC are not capable of learning to read or write.[105][108] As a result, young AAC users are often given fewer opportunities to engage in reading and writing activities outside of the classroom, which limits the amount of time, range, and quality of experience.[108][109] However, current research suggests that with direct and explicit reading instruction, AAC users can better develop their literacy skills, leading to more participation in academic, vocational, and community activities.[110][111]

History of AAC

Although AAC can trace its roots back to the early days of Ancient Rome, with the first use of augmentative strategies for the Deaf, its modern inception began in the 1950s. At this time, AAC devices were mainly implemented for those whose oral and laryngeal anatomy was damaged by surgical procedures such as laryngectomies and glossectomies.[112] There was little thought given to the use of AAC strategies for those with severe communications impairments resulting from other origins. Despite this, manual languages proliferated naturally in the Deaf community. Members of this community began to actively pursue their right to be educated using American Sign Language (ASL) during the 1960s, coinciding with the United States Civil Rights Movement. This activism helped increase public and governmental awareness of the issues related to AAC. At this time, the first academic text to discuss ASL as a true language, Sign Language Structure, was released and Total Communication, an educational approach for the Deaf, was developed.[112]

During the late 1960s, it became acceptable to use manual sign languages with individuals who had both hearing and cognitive impairments. The use of AAC devices was also prevalent among those for whom it seemed that intelligible speech would likely never be possible, including those with severe dysarthrias, cerebral palsy and amyotrophic lateral sclerosis. However, in most cases AAC strategies were only employed after traditional speech therapy had failed, as many felt hesitant to provide non-speech intervention to those who might be able to learn to communicate verbally.[112][113]

This view continued to dominate the field until the 1970s, when several acts of government helped to expand the application of AAC strategies.[citation needed] In 1975, the Education for All Handicapped Children Act (P.L. 94-142) (later renamed the Individuals with Disabilities Education Act (IDEA)) sanctioned the provision of educational services for all school-aged children with disabilities. As a result, many children with disabilities entered the public school systems, compelling classroom teachers to find ways in which to assist communicative exchanges. The 1986 Education of Handicapped Act Amendments (P.L. 97-457) promoted the use of technological devices to help accomplish the aforementioned goal.[112][113]

During the beginning of the 1980s, AAC became an area of professional specialization. Articles, newsletters, and textbooks on the matter were published as well as the first international conferences. The American Speech-Language-Hearing Association published a position paper regarding AAC as a field of practice for speech-language pathologists in 1981, and in 1983, the International Society for Alternative and Augmentative Communication(ISAAC) was founded.[112]

The Technology-Related Assistance for Individuals with Disabilities Act (P.L. 100-407) was announced in 1989 and declared that all states make every possible effort to provide access to assistive devices and technologies to citizens, regardless of age, disability, or location of residence. A variety of other acts at the time sought to highlight the importance of disseminating information regarding assistive technologies and the right to their access to the general public. In 1992, the Communication Bill of Rights, set forth by the National Joint Committee for the Communication Needs of Persons with Severe Disabilities, stated that all individuals with severe communication disabilities have a right to use AAC devices at all times as well as a right to information and the opportunity to have and make choices.[112][113]

Since the 1990s, there has been an increase in in-class and natural education techniques, as opposed to traditional pull-out methods, which has led professionals to seek ways for children with disabilities to participate more comprehensively and successfully in classroom activities. This inclusion model promotes the enrichment of functional skills taught within a natural context. The 1997 amendments to the Individuals with Disabilities Education Act (previously the Education for Handicapped Children Act) mandated individual assessment of children’s assistive technology needs, including augmentative communication as well as consideration of these needs in students' Individualized Education Program. The field of AAC now follows a participation or universal model, believing that anyone can communicate and benefit through the use of AAC devices and methods.[112][113]

User's experiences with AAC

When adults with complex communication needs enter hospitals, they often have difficulty communicating with hospital staff members, as there are many potential communicative barriers in this situation. Bed-ridden individuals who cannot access an AAC system may not have a way to communicate. Patients may not have the opportunity to communicate if the staff members perceive it as a time-consuming task. Additionally, there may be a lack of understanding on the part of hospital staff, with respect to a patient's communicative attempts. As a result, the staff may not respond to these attempts at communication.[114] Family members tend to take over and speak on behalf of the patient to the doctors and nurses. In one study that interviewed adults with cerebral palsy (CP), it was expressed that doctors would speak to the family instead of the patient, since the patients needed time to communicate using AAC.[citation needed] It was also felt that the doctors were too busy. One patient recounted a success story where his brother taught the nurse how the patient communicates with the AAC and then the patient used the AAC to communicate with the nurse directly.[115] The implication of this scenario is that communication is possible. As long as hospital staff are aware of other communication modes (AAC), family members are willing to be less protective, and patients can have enough confidence to speak for themselves. The consensus of these interviews is that adults with complex communication needs wish to be treated like adults while they are in hospital, and they would like to be involved in decision-making about their health care.[citation needed] They also want to be involved in the education of hospital staff about AAC communication.[115] Doctors and nurses need to become familiar with AAC systems and have some knowledge/skills on how to interact with patients with complex communication needs.[114]

Outcomes

Literacy Children with disability using Alternative Augmentative Communication (AAC) systems are at risk for impoverished literacy.[116] The poor literacy outcomes result from poorer reading skills that these children tend to have. Their difficulty in reading stems from their limited use of speech and language. As children, AAC users often have difficulty with articulation, grammar, semantics, syntax and narration. These language elements are not only important for producing and understanding language but also for developing reading and writing skills.[116] Since AAC users tend to have limited experience/exposure to print, they gain less knowledge about the world and vocabulary.[117] Teachers tend to have lower expectations for reading achievements from individuals using AAC and this may affect the quality and quantity of literacy instruction they receive.[118] Due to communication barriers, these children may have less opportunities for asking questions and to inquire about missing information in texts and during classroom book reading times. They may receive less guidance and have more limited opportunities to practice with books. The resulting poorer literacy outcomes may limit AAC users in educational and vocational opportunities.[118]

Employment Physical disability may reduce the ability to work. Individuals with severe physical disabilities are often forced to discontinue their work. According to U.S. Census Bureau (1997), amongst the severely disabled individuals, less than 10% were employed. Despite the various barriers to employment, it is possible for AAC users to achieve success in educational endeavors and employment.[119] Although, the types of jobs these individuals are involved in are often low-paying jobs,[120] some AAC users also maintain higher-skilled jobs. Individuals with a severe disability like ALS using AAC have been found to continue working.[121] Their positive work experiences were related to a positive and supportive work environment. Access to AAC, determination and a positive attitude was what helped the individuals in this study to participate in society and have a good quality of life.[121] Personality factors that have been found to be related to employment are a strong work ethic and access to AAC technology. Family support, education and work skills are also related to positive employment outcomes.[122] Community networks (friends and family) have also been found to help in work opportunities.[122]

Quality of life There have been reports of AAC users to have satisfying relationships with family and friends. They can engage in pleasurable and interesting life activities and they may remain optimistic even when unemployed.[119] There may, however be more negative post-school outcomes,[119] especially when post-secondary education or employment are not pursued. The negative outcomes are more related to dissatisfaction with the service delivery and AAC supports, which results in communication barriers for AAC users. These issues reflect issues with policy barriers, lack of resources, and dissatisfaction with communication devices that exist for AAC users.[119]

Coinciding with a move towards evidence-based practice within speech-language pathology and health care in general, speech-language pathologists have increasingly been interested or even required to demonstrate the effectiveness of their interventions.[123] Within the field of AAC, this effectiveness can be measured according to a number of parameters related to the client and his or her family including participation, functional communication, consumer satisfaction and quality of life.[98] Several tools, both general and more specific to AAC, exist to measure outcomes of intervention. The QUEST (Quebec User Evaluation of Satisfaction with Assistive Technology) is a standardized interview or questionnaire designed to assess an AAC user's satisfaction level.[124] Another measurement tool developed by the American Speech-Language Hearing Association (ASHA), is the FCM (Functional Communication Measure). The FCM for Augmentative and Alternative Communication is a seven-point rating scale, ranging from least functional (Level 1) to most functional (Level 7). It is one of fifteen such scales that represent a continuum along which to describe the different aspects of a patient’s functional communication abilities over the course of intervention.[125] Research projects and Data bases have also been established to advance the area of outcomes measurement within the broader field of assistive technology by improving the field’s ability to measure the impact of Assistive Technology on the lives of people with disabilities while determining the effectiveness and usefulness of devices and services.[126]

Terminology used in AAC

Symbol: Something used to represent another thing or concept. For example, a picture or line drawing of a dog to represent dog.

Symbol Set: A set of symbol that is closed in nature; symbol set can be expanded, but it does not have clearly defined rules for expansion (e.g., Picture communication symbols).

Symbol System: A set of symbol; includes rules or a logic for the development of symbols (e.g., Blissymbols).

Speech Generating Device: An electronic assistive device that produces speech (e.g., Dynavox, Mercury).

VOCA: Voice Output Communication Aid; other term for electronic assistive device producing speech.

AAC System: An integrated network of symbols, techniques, aids, strategies, and skills.

Input Method: Technique used to select representations of the wanted utterances from an electronic device (e.g., touch screen selection, eye gaze pointing, switch access).

See also: Blissymbolics.

Bibliography

  • Beukelman, D, & Mirenda, P (2005), Augmentative & Alternative Communication: Supporting Children & Adults With Complex Communication Needs , Paul H Brookes, Baltimore

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