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Experimental Evaluation of a Parent-Implemented AAC Intervention Protocol for Children with Severe Autism
Two popular interventions in augmentative and alternative communication (AAC) for prelinguistic children with autism are picture exchange communication system (PECS) and speech-generating devices (SGDs). Research demonstrated positive effects on functional communication when these two strategies were combined (Boesch et al., 2013). Furthermore, AAC interventions can be implemented by clinicians or parents. Parent implementation shows benefits, and parent involvement is considered crucial in autism intervention (National Research Council, 2001).
Objectives:
This study aimed to answer: (a) what effects does a parent-implemented intervention have on developing functional communication skills and natural speech development; (b) to what extent can parents implement AAC intervention with high fidelity; and (c) to what extent are parents satisfied with intervention procedures and effectiveness?
Methods:
A multiple probe design across participants evaluated treatment effects of the parent-implemented intervention. The protocol contained the first five phases of the PECS approach, followed by generalization and maintenance phases. Dependent measures were: (a) The number of correct requests during a 20-trials session; and (b) the number of vocalizations or word approximations. Intervention phases targeted requesting for food; generalization probes were taken for requesting toys.
Materials included an iPad equipped with SPEAK now!, a sensory-friendly autism app designed to mimic PECS. Parent-training included video resources, written instructions, modeling, role-play, and review of video-taped sessions with feedback.
Inter-observer agreement (IOA) for dependent measures and treatment implementation was established by re-scoring 40% of all sessions. Mean IOA was 99% for requesting, and 92% for emerging speech. Treatment integrity ranged from 82- 98% across parents.
Results:
Children 1 and 2 mastered all five phases of the parent-implemented training, whereas child 3 only achieved phase 3. Acquisition rates varied across subjects, with children 1 and 2 needing on average 6 sessions to master each phase, and child 3 needing 7 sessions. The largest gain appeared when requesting was targeted: For child 1, requesting improved from a baseline mean of 0.25 to a maintenance mean of 17.75; for child 2 from 1.1 to 17.5; and for child 3 from 0.6 to 11.3. All three participants showed generalization to untrained items. Effect size estimates indicated a “highly effective” intervention. Results differed for emerging speech: whereas child 1 made noticeable gains from a baseline mean of 16 to a maintenance mean of 24 word utterances, moderate gains were observed for child 2 and no gains for child 3. Effect size scores were “fairly effective”, and “ineffective”, respectively.
Conclusions:
Results suggest parents can implement an iPad-based AAC intervention with sufficient fidelity. Children may not be able to complete all protocol phases, and performance may vary with level of intellectual impairment. Treatment effects are most noticeable for requesting skills. A facilitative effect on natural speech development seems most likely for participants with some pre-treatment speech ability. Although these speech effects may seem negligible, such patterns are consistent with previous PECS research. Results underscore the potential of including parents for maximizing benefits of AAC intervention in autism. Practitioners should recognize the value of joint parent-professional partnerships, and develop expertise for parent training.