Instructional strategies used in direct AAC interventions with children to support graphic symbol learning: A systematic review

Augmentative and alternative communication (AAC) refers to a wide range of aided and unaided modes that are employed with a diverse group of people to support a range of language and communication outcomes. Children whose comprehension of spoken language greatly exceeds their ability to express themselves within that modality can be described as expressive users of AAC. Interventions are important in promoting language acquisition and the expressive use of graphic symbols. Instructional strategies employed within interventions have an important impact on treatment effectiveness. A systematic review was undertaken to identify instructional strategies that have demonstrated effectiveness in supporting graphic symbol learning and aided language development in direct interventions with children aged 0-18 years who are expressive users of aided AAC (including children without learning difficulties and those with mild-moderate learning difficulties). A comprehensive search strategy was carried out and all studies meeting the inclusion criteria were quality appraised. A data extraction procedure was conducted on the studies meeting the quality appraisal criteria. Fifteen studies were included in the review investigating four instructional strategies used to support graphic symbol learning. The most studied instructional strategy, aided modeling, can be considered an evidenced-based practice. There is also strong research evidence to support the use of both narrative-based interventions and mand-model procedures to facilitate graphic symbol learning and aided language acquisition in children who are expressive users of aided AAC. However, across the literature reviewed, a lack of consistent terminology hampered the ability to compare studies and draw conclusions. More consistent use of terminology would enhance the utility of the evidence base.