The effect of aided AAC modeling on the expression of multi-symbol messages by preschoolers who use AAC.

A single subject, multiple probe design across participants was used to evaluate the impact of using aided AAC modeling to support multi-symbol message production. Five preschoolers (three who used voice output communication systems, two who used non-electronic communication boards) participated in the study. Aided AAC models were provided by pointing to two symbols on the child's aided AAC system and then providing a grammatically complete spoken model while engaging in play activities. Four of the five preschoolers learned to consistently produce multi-symbol messages; the fifth did not demonstrate consistent gains. The four preschoolers who met criterion all evidenced long-term use of symbol combinations and generalized use of symbol combinations to novel play routines. Results, clinical implications, and future research directions are discussed.