Comparison and Preference: Manual Signing, Picture Exchange, and Speech-Generating Devices as Communication Modes for Children with Developmental Disabilities

Children with autism spectrum disorder (ASD) and related developmental disabilities (DD), who do not speak or have very limited spoken language, are often candidates for augmentative and alternative communication (AAC). Three common modes of AAC are manual signing (MS), picture exchange (PE), and speech-generating devices (SGDs). Studies suggest that children with ASD and other DD might demonstrate comparable proficiency in learning to use each of these communication systems. Because there may not be one single mode of AAC that appears to be most readily taught to, and learnt by, these children, decisions regarding which AAC mode to implement might need to be based upon an assessment of the individual's preferences for using different AAC systems.  Giving students the opportunity to self-select their most preferred AAC mode could also be viewed as one way of promoting self-determination in AAC intervention and this in turn might significantly influence progress in learning to communicate and maintenance of newly acquired AAC skills. The three empirical intervention studies that are presented in the present thesis each made use of systematic instructional procedures, based upon the principles of applied behaviour analysis (ABA), to teach children with ASD and other DD to request (mand) preferred items using MS, PE, and SGD. A key aspect of the studies was the assessment of each child's preference for using one of the three AAC modes via a structured choice-making protocol. This choice-making protocol was designed to determine whether children made greater progress, showed increased communication ability, and continued to use AAC during follow-up sessions when their preferences for different AAC options were assessed and incorporated into the intervention process.  Utilising single-case research methodology (combined multiple-baseline and alternating-treatments designs), a total of 12 participants (9 boys, 3 girls, aged 4 to 13 years) received interventions that were designed to compare acquisition, maintenance, and preference for MS, PE, and SGD. Overall, the results of the three studies demonstrated that seven of the 12 (58%) participants learnt to use, and reached criterion, for use of each AAC option. Five participants did not reach criterion for MS. Two participants did not reach criterion for PE and one of these participants did not reach criterion for SGD. Eight of the 12 (67%) participants appeared to show a preference for using the SGD. Preference for using PE was demonstrated by three out of eight (38%) participants (PE was only assessed in Studies 2 and 3). Finally, one out of the 12 (8%) participants appeared to show a preference for using MS.  These data suggest greater proficiency and better maintenance when children used their preferred communication option. These findings highlight some potentially positive effects of enabling some degree of self-determination with respect to aspects of the use of AAC systems in communication intervention. Given the encouraging intervention outcomes for the present series of three studies, future research and practice should continue to seek ways of increasing opportunities for self-determination in AAC and related interventions for individuals with ASD/DD.