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Feedback
- can be visual, auditory, or tactile
- activation feedback
- message feedback
- occurs primarily during selection
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Activation feedback
- lets user know that an item has been selected
- click or beep (signal that something was selected)
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Message feedback
- provides user with information about the message he/she has formulated or selected
- the actual word that was selected
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Output
- can be visual, auditory, or tactile
- occurs after the message is selected
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Auditory message output
- digitized speech- natural speech or environmental sounds that have been recorded, stored, and reproduced
- synthesized speech- text entered via keyboard is converted to a pronunciation code using a dictionary and a set of rules in an algorithm
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Advantages of digitized speech
- with current technology, it sounds the closest to natural/human speech
- individuals can access a number of predetermined messages
- messages are generally easy for a facilitator to program
- messages can be easily changed
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Disadvantages of digitized speech
- digitized speech requires a large amount of computer memory
- prevent individuals from being able to generate novel messages (because messages must be pre-stored, the individual is limited to these messages)
- to create digitized messages, facilitator is needed to record or help record the desired messages (to maintain gender and age appropriateness, an individual of the same gender and approximate age is preferred to record messages)
- the system is sensitive to background noise during recording
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Advantages of synthesized speech
- reduces the partner's burden in the interaction
- provides information in a mode that is relatively familiar and nonthreatening
- allows for communication with partners that are non-literate but understand spoken language, or those who are visually impaired
- allows messages to be sent without first obtaining the partner's attention through some other mode
- allows communication to occur at a distance
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Disadvantages of synthesized speech
people with hearing impairments, reduced recpetive language, or in a noisy environment may find it difficult to understand
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Intelligibility
- the adequacy of the acoustic signal to transmit sounds or convey meaning
- describes what a listener is able to perceive from a speech signal
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Summary of intelligibility scores for common speech synthesizers
- intelligibility is generally low
- intelligibility is higher in sentences than in single words
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Factors influencing intelligibility of synthesized speech
- context (words vs. sentences vs. discourse, high-predictability vs. low-predictability, etc)
- practice
- noise
- age
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Comprehensibility
- the adequacy of the speech signal to impart meaning in a functional context
- affected by the intrinsic factors that affect intelligibility, but also by extrinsic factors (listener familiarity, syntax, semantics, environmental conditions)
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Listener comprehension of synthesized speech
- comparable to comprehensibility of natural speech
- there are processing costs associated with comprehending synthesized speech (latency of responding- sentence verification task, sentence by sentence listening task)
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Factors influencing comprehension of synthesized speech
- rate of speech
- output method
- noise
- age
- divided attention
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Visual message output (types)
- LCD
- CRT
- LED
- e-ink and e-paper
- hardcopy print out (paper)
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LCD
- liquid crystal displays
- two plates of glass with liquid crystal material between them
- reflective, transmissive/backlit
- transreflective
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LED
- light emitting diode
- type of LCD
- main difference is in how the backlighting is provided
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CRT
- cathode-ray tubes
- computer screen display
- bigger and bulkier than an LCD, they consume more power and are prone to screen flicker
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Principles of vocabulary selection
- vocabulary should be individualized
- vocabulary should be age, gender and culturally appropriate
- vocabulary should reflect the personality of the learner
- learner should be involved in vocabulary selection
- vocabulary selection is a dynamic process- vocabulary should be added and changed as needed
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Need to select vocabulary that
- is varied
- frequency of use
- allows a range of functions
- is interesting
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Need to select vocabulary that allows learners to use the four functions of interactions
- communication of needs/wants
- information transfer
- social closeness
- social etiquette
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Vocabulary selection classifications
- core
- fringe
- coverage
- developmental
- combinatory
- acceleration
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Core
words/messages commonly used given a situation
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Fringe
words/messages specific to a particular learner/activity (personalized vocabulary for the person based on their preferences)
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Coverage
vocabulary needed to communicate essential messages
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Developmental
vocabulary that the learner doesn't yet know that may encourage vocabulary growth
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Combinatory
vocabulary that encourages combinatory use of symbols
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Acceleration
words or phrases that occur frequently and need to be communicated quickly
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Levels of vocabulary generality
- generalized- broad topics (want- food, drinks)
- generic- more specific, types of categories (cookies, fruit, soda pop, juice)
- explicit- even more specific, tells you exactly what it is (oatmeal raisin, wafer, apple, root beer, orange juice, etc)
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Generalized request advantages
- addresses the possibility that the learner might become tired of the same item
- can be used at a variety of times, in a variety of places
- addresses learners who do not have stable preferences
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Generalized request disadvantages
- does not promote independence in natural environments (places large communicative burden on listener)
- requires at least several different reinforcers
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Explicit request advantages
- places minimal communicative burden on listener
- teaches one to one symbol (reference correspondence)
- can be used if a learner has only a single strong reinforcer
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Explicit request disadvantages
- limited opportunities to use each item- especially if learner becomes tired of item
- settings and events in which opportunities can be implemented may be limited
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Methods for selecting vocabulary
- blank sheet
- categorical formats
- vocabulary checklists
- communication diaries
- ecological inventories
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Blank sheet
- asks others "what would the learner say if he/she could speak?"
- interview others to get vocabulary
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Blank sheet advantages
identifies most important/salient vocabulary
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Blank sheet disadvantages
- may not consider everything
- reflects the priorities of person developing list
- overwhelming task
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Categorical formats
provides categories to help think of possible vocabulary (names, toys, school, animals, etc)
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Categorical formats advantages
provides a structure for thinking about vocabulary
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Categorical formats disadvantages
areas not addressed on the inventory tend to be omitted
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Vocabulary checklists
- word inventories- lists of all potential words
- commonly-used word lists- lists common vocabulary for different age or disability groups, word lists based on vocabulary use patterns of successful augmentative system users, word lists from natural speakers
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Word inventories advantages
- comprehensive
- may include words that hadn't been considered
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Word inventories disadvantages
- not learner-specific
- may not have enough structure to know what's appropriate
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Commonly-used word lists advantages
- less time consuming
- easy to use
- useful as a final check
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Commonly-used word lists disadvantage
lack words specific to learner
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Communication diaries
- keeping track of communication needs across time
- when breakdowns occur, write down what vocabulary was needed
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Communication diaries advantage
targets the problem areas
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Communication diaries disadvantages
- partner may not recognize all communication opportunities
- if the breakdown is never repaired, wouldn't know what vocabulary was needed
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Ecological inventories
- detailed analysis of the environment and the learner's communication/vocabulary needs
- considers communication obligations and communication opportunities
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Completing an ecological inventory
- 1. identify environments and specific activities and settings
- 2. conduct a detailed on-site analysis of communication requirements of non-disabled persons during activities
- 3. conduct a detailed on-site inventory of the learner's participation during those same activities
- 4. conduct a discrepancy analysis to determine any communicative needs of the learner
- 5. identify appropriate vocabulary to fulfill communication needs
- 6. determine priorities for vocabulary
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Ecological inventory advantages
- capture key functional vocabulary
- systematic
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Ecological inventory disadvantages
- can be limiting: impossible to anticipate everything
- specific only to the environment inventoried
- time consuming
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General issues with vocabulary selection
- variety of methods
- several informants
- consider age appropriateness (adults have the right to swear, kids have the right to get in trouble)
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Deciding on a word/phrase based system
- cognitive expectations
- selection technique
- time dependent nature of activity
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Cognitive expectations for vocabulary selection
- can learner chain symbols together in a matching task?
- will literacy instruction be implemented?
- can learner move between pages or levels to locate symbols?
- if you answer yes to any of these questions, use a word based system
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Selection technique
- scanning selection techniques are very slow when a number of keystrokes are required to select a message
- word prediction may help to compensate for this slowness
- phrase based systems are faster
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Time dependent nature of activity
some activities (e.g. urgent messages) offer small windows of time in which to respond (cheering for the 3-point shot at the basketball game, responding to a question in a one-on-one interaction, teacher asks for volunteers to bring lunch orders to the office)
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Instruction block/introduction strategy
- information on the learner's means of communication and strategies for partner to use to facilitate communication
- designed to "instruct" unfamiliar communication partners regarding how the learner communicates
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Components of introduction strategy
- basic information about the person
- information about the means of communication
- information about what the partner can do to facilitate communication
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AAC assessment and intervention
- is a dynamic process
- has a focus on functional communication in the real world
- involves multiple sessions in various contexts (e.g. home, school, community)
- is integrally linked to intervention
- has a base in DATA
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Why assess via the team approach?
- intervention decisions are based on a broad range of information
- one professional cannot and should not attempt to obtain/provide the all the necessary information
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The AAC assessment team
- individual who uses AAC
- family members/significant others
- SLP
- OT/PT
- educational professionals
- medical professionals
- rehab engineer
- vocational counselor
- other areas of consultation
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Goal of assessment
- gather sufficient amount of information for the AAC team (user, family members, professionals, etc.) to make intervention decisions (meet current communication needs, future needs)
- assessment usually ongoing, require multiple sessions
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Two-pronged model of assessment
- focus on the individual to ensure that he or she has the means and skills to communicate effectively
- focus on the facilitators to ensure that the individual has the opportunity and necessary support to communicate effectively
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Assessment strategies
- interviews (the individual and the facilitators)
- surveys and checklists (e.g. communication needs survey)
- naturalistic observations
- formal and informal tests
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Adapting assessment procedures
- many norm-referenced tests cannot be administered according to set procedures (lack of ability to verbally respond, manipulate objects and pictures, standard time limitations unrealistic)
- standardized tests not usually necessary for AAC assessment (not comparing individual to peers of same age, not predictive of AAC use)
- alternatives to standard testing formats (cut test pages apart, use yes/no verbal scanning, use multiple choice)
- account for possible invalidation of assessment (increased possibility of guessing, unintentional evaluator cues)
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Components of assessment
- 1. identificaiton of communication needs and barriers
- 2. assessment of skills
- 3. identification of partner strategies to facilitate communication and of environmental barriers that impede communication
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Identification of communication needs
- determine the type of input the person needs to be able to understand
- determine with whom, when, where, why, about what, and how the individuals needs to communicate
- investigate communication patterns and identify unmet needs
- review unmet needs and identify priorities
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Assessment procedures
- interview both the person and the facilitators
- complete a communication needs survey
- conduct ecological inventories in naturally occurring interactions
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How to conduct ecological inventory
- 1. observe the individual in daily life; review videotapes of daily life
- 2. observe peers
- 3. identify typical environments, activities, partners, positioning, communication needs (frequent, difficult, and successful situations should definitely be observed)
- 4. conduct discrepancy analysis to determine the individual's effectiveness
- 5. identify unmet needs and limitations to participation (opportunity barriers)
- 6. determine priorities (needs that are not met in frequent situations)
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Identification of communication barriers goals
- 1. to identify any barriers imposed by society or by the individuals' partners that limit the individual's participation and communcation in daily life
- 2. to identify strategies and supports that facilitate the individual's communication and participation
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Policy barriers
- result from legislative or regulatory decisions, policies
- e.g. segregation policies, limited use policies
- require lobbying, advocacy for legislative or policy change, legal action if necessary
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Policy supports
regulations and legislation that support individuals who require AAC
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Practice barriers
- result from conventional practice (not actual legislation)
- require advocacy, may require legislation to chage
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Practice supports
becoming more common with more educated professionals about AAC and individuals who require AAC
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Attitude barriers
- result from the negative attitudes of an individual or group
- education, public awareness are needed to change these
- provide individual with an introduction strategy
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Knowledge barriers
- result from a lack of information about AAC (systems, services, funding)
- require instruction and education of communication partners (professionals, family and friends)
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Skill barriers
- result from a lack of skills in interaction with the individual who requires AAC
- can be changed by intervening with partners and providing them with the skills they need to interact with individuals who require AAC
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Assessment of sensory-perceptual skills
functional visual and audiological assessments using AAC materials (e.g. visual field as it relates to positioning of partners and materials)
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Assessment of receptive linguistic skills
- determine the type of spoken language input that is appropriate
- determine when and how augmentation of spoken input is required
- identify discrepancies between comprehension and expression
- procedures may include: standardized receptive language tests (adapted), systematic observations of receptive language performances in daily interactions, informal clinician developed assessment tasks (e.g. responses to specific types of wh-questions during play), dynamic assessment of augmented input
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Assessment of expressive language skills
- turn-taking
- initiation/response patterns
- communcative functions
- modes of communication
- natural speech intelligibility
- procedures may include: conduct systematic observations of naturallly occurring interactions, utlilize informal eliciting contexts to probe specific skills
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Assessment of literacy
- determine if written language is appropriate as a communication modality
- assess reading and spelling
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Assessment of cognitive skills
- symbol representation (complete dynamic assessment, recpetive language task, yes/no task, visual matching task, question/answer task, request task)
- organization (sorting task using relevant vocabulary, pairing task using relevant vocabulary, trial system use and evaluation)
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Assessment of motor skills
- requires the expertise of OT/PT
- motor tasks to probe production of hand shapes, orientations, positions, and movements
- assess accuracy and efficiency of access techniques to control aided systems
- complete functional seating and positioning assessment
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Facilitator strategies and opportunity barriers
- building communicative competence is an interpersonal process, not an isolated phenomenon; participants influence each other in the course of the interaction
- investigate the interaction strategies used by partners to facilitate communication
- identify any barriers that limit the individual's opportunities to communicate
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Examples of barriers to successful communication
- policy barriers
- practice barriers
- attitude barriers
- knowledge barriers
- skill barriers
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Facilitator strategies and opportunity barriers: assessment procedures
- interview the individual and facilitators as appropriate
- conduct systematic observations of naturally occurring interactions with a focus on partner behaviors
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