cial, hand-made, or customized device or service used to support or enhance the functional capabilities of individuals with disabilities. AT includes computer-assisted instruction, mobility devices, high and low technology adaptations and AAC.
The methods and tools of AAC interventions, properly applied, are tailored to unique strengths and needs of individuals with autism. AAC includes the use of visual language systems, such as visual icons or words representing specific communicative units, which capitalize on strong visual processing of many children with autism. The visual information is static and predictable, and enables the child with autism to rely on recognition rather than recall memory to receive language input or generate language output. AAC provides a motorically simple way to communicate needs and may preempt the development of challenging coping behaviors. Low-technology AAC tools, such as picture systems, can be relatively simple and inexpensive to implement (Hodgdon, 1995).
There is empirical evidence that systematic teaching of speech using a naturalistic behavioral approach is efficacious for many children, particularly if treatment can begin by 2-1/2 years of age (McGee et al., 1999). However, a substantial proportion of children fail to make meaningful gains in speech (with failure rates ranging from about 20 percent to 40 percent). For those children who do acquire speech, the degree of spontaneity and complexity of language is not clearly reported in most research studies. There is now a body of research on AAC and speech and language acquisition in children with autism that is important to consider, particularly for those children who make slow or minimal gains in other programs.
There is a dearth of research on communication assessment strategies for children with autism using AAC. In one case study of a child with autism (Light et al., 1998), the AAC assessment principles of the Communication Participation Model (Beukelman and Mirenda, 1998) were implemented to gather information needed for an effective AAC intervention. Based on this participation plan and a variety of informal assessments, a comprehensive multimodal AAC intervention (speech, pointing, a communication book, a laptop computer with synthesized speech) was implemented, increasing the level of communication and participation for this child.
There have been numerous experimental studies of the efficacy of teaching sign language to children with autism (see Goldstein, 1999). These studies have demonstrated that total communication (speech plus sign language) training resulted in faster and more complete receptive