Aided language stimulation is an augmented input strategy that facilitates the expressive and receptive language skills of persons who require augmentative and alternative communication (AAC). The aim of this study was to determine and compare the acquisition of receptive vocabulary items during implementation of aided language stimulation with dosages of 40% and 70%, respectively. An adapted alternating treatment design was replicated across six participants with complex communication needs and severe intellectual disability. All participants demonstrated receptive vocabulary acquisition when aided language stimulation was provided with a dosage of 70%, and two participants demonstrated acquisition when a dosage of 40% was provided. Receptive vocabulary acquisition was maintained following a 6-day withdrawal period. The dosage of augmented input may impact receptive vocabulary acquisition for children with complex communication needs and severe intellectual disability, with higher dosages being more effective for some participants. The findings indicate that clinicians should be aware that dosage is an important consideration when providing aided language stimulation to facilitate receptive vocabulary acquisition in children with complex communication needs and severe intellectual disability.
Keywords: Adapted alternating treatment design; aided language stimulation; augmented input; complex communication needs; dosage; intellectual disability; receptive vocabulary acquisition.