AAC-RERC Development Project D2
www.aac-rerc.com

Initially, AAC interfaces used "fixed display" strategies. Symbol sets (i.e., line drawings, orthographic letters, or photographs) were displayed and messages were stored in locations associated with these displays. These fixed displays forced AAC users or an AAC facilitator to remember where messages were stored. Recently, dynamic screen technology has been used extensively. Displays are represented electronically on a touch or computer screen. When a location is activated, a new screen displays containing symbols related to the item selected on the previous page. This dynamic screen interface can be many levels/screens deep and requires extensive recall memory for the user to retrieve a given message. Fixed and dynamic screen AAC interfaces that make extensive demands on recall memory are difficult to use for persons with memory limitations.

The memory demands of fixed and dynamic displays have had two important impacts on the AAC field. First, many users are unable to operate devices that require recalling complex symbol message relationships. This is particularly true for persons with cognitive limitations. Second, extensive training must take place to become proficient. Unquestionably, some users, after extensive training and practice, become quite automatic with these interfaces. This project addresses the development of an interface that relies more extensively on recognition rather than on recall memory. Persons who are unable to accomplish the memory demands of the fixed and dynamic screen interfaces often have fairly well-preserved recognition memory even though recall memory may be impaired.

This project is designed to develop an interface that will be useful with several types of individuals who have memory limitations. In addition, this interface will be useful for adults with acquired disabilities who do not wish to learn a complicated fixed or dynamic screen interface. These include adults with acquired disabilities who do not have the time or do not wish to learn an alternative symbol system, and adults with memory and cognitive limitations. AAC users with memory and cognitive limitations include those with traumatic brain injury, aphasia, and accompanying dementia such as progressive aphasia, Huntington's disease, Parkinson's disease, and multiple sclerosis.

Specification and design phase - Design specifications were completed; the prototype was developed in three different versions: orthographic, iconic, and graphic (Chinese); design specifications were verified in the prototype; and four TBI survivors with cognitive limitations demonstrated the ability to operate the interface and compare accuracy and efficiency on AAC Menu and dynamic screen interfaces.

Error-free (reduced) Studies with non-disabled adults - We completed a study on the use of AAC Menu as an error-free learning strategy to teach alpha codes for word and message retrieval. We initiated a similar study involving persons with TBI who use AAC system and formulate messages on a letter-by-letter basis (no use of encoding strategies).

Case study comparison of AAC Menu and semantic compaction strategies - We completed a single case study (9 year old with cerebral palsy) of the use of AAC Menu (iconic version) and the Vanguard™. Although he has used the Vanguard system for several years, he retrieved familiar words with similar accuracy and slightly less speed with AAC Menu as compared to Vanguard. For unfamiliar words, AAC Menu use was much more accurate and rapid than Vanguard.

Ongoing study with persons with aphasia - We are conducting a study comparing messaging accuracy and rate using AAC Menu and DynaVox interfaces by persons with severe language disorders (aphasia) due to stroke. The digital photo stimuli are currently being prepared, and the same stimuli will be incorporated into each of the interfaces.

• The prototype, designed to reduce recall learning and rely on recognition learning, can be implemented in current computer technology in both orthographic and graphic versions.
• Persons with marked cognitive impairments can learn to operate the interface.
• AAC Menu interface can support error-free learning in non-disabled adults and in TBI participants.
• For a child with cerebral palsy who routinely uses a semantic compaction AAC strategy, AAC Menu interface can be used to communicate unfamiliar vocabulary much more quickly that a semantic compaction strategy. AAC Menu interface can be used to retrieve familiar vocabulary slightly slower than semantic compaction.

(the links below will open in a new window)

• Barkley Speech and Hearing Clinic, University of Nebraska- Lincoln
• Munroe/Meyer Institute for Genetics and Rehabilitation
• Madonna Rehabilitation Hospitals
• University of Nebraska Medical Center- Omaha Neuromotor Clinic & Geriatric Unit
• Communication and Assistive Device Laboratory, State Univesity of New York at Buffalo