corded) speech. Particular messages can be accessed through visualgraphic symbols, words, or letters on the VOCA display. A VOCA can range from a single switch device that delivers a limited number of voice messages to a more complex VOCA that delivers a series of communicative units or messages, often related to a specific theme or activity, and has the capability for thousands of messages. Dynamic display devices are VOCAs in which a child points to a particular generic symbol, such as “lunch”, and a new “lunch specific” board instantly opens up with the vocabulary needed for the child to make requests, interact, comment, and question within the lunch context. Some highly sophisticated VOCAs have large capacities for storing complex spoken and written text and can operate with personal computers.
A possible advantage of a VOCA over a low-technology symbol board is the ability to facilitate more normalized, natural interactions and provide verbal models for speech development due to the voice output. Four preschool children with autism with little or no functional speech were taught to use VOCAs with line drawing displays to make requests. Using a naturalistic behavioral teaching method, all four of the children successfully learned to use their VOCAs to request, make social comments, and respond to questions in a contextually appropriate and spontaneous manner in 1 to 3 months (Schepis et al., 1998). These findings are preliminary but suggest the potential value of VOCAs to support communicative interactions of children with autism.
In addition to using visual symbols for communicative output, AAC interventions have also used visual symbols to augment communicative input from others. Recently, this equally important “input” aspect of AAC is being recognized, and several case studies demonstrate the effectiveness of augmented input for young children with autism (Hodgdon, 1995; Quill, 1997; Peterson et al., 1995). One of the most widely used AAC input techniques is the use of visual schedules. The visual schedule enables a child with autism to understand the sequence of an activity through the visual input. The TEACCH (Treatment and Education of Autistic and Related Communication Handicapped Children) program, developed and implemented in North Carolina for almost 30 years, has utilized visual schedules and protocols to promote independence, self-management, and task completion (Schopler et al., 1983; Marcus et al., 2000; see Chapter 12). A few studies have demonstrated independent task engagement and completion through pictorial representation of the task components, called “within-task” schedules (Hall et al., 1995; Mirenda et al., in press; Pierce and Schreibman, 1994). Schedules that provide predictability as students transition from one activity or environment to another are called “between-task” schedules and are also being implemented with young children with autism; however, evidence of success is only in case study format.