Studies of participants aged less than 21 years with a diagnosis of orthopaedic impairment (such as cerebral palsy) or a developmental disability (such as intellectual disability) who used an aided AAC device to communicate or were taught to use one over the study period were eligible for inclusion. Aided AAC was defined as use of an external device for message production (such as picture communication boards, voice output communication aids). Studies were required to use a recognised research design; descriptive case series studies were excluded. Studies were required to describe instruction aimed at increasing or improving participants' literacy or emergent literacy skills including phonemic awareness, phonics, oral reading fluency, vocabulary related to texts, text comprehension or participation in literacy activities (such as turn taking during storybook reading, creating a fictional narrative). Studies that targeted communication outside of literacy activities, that aimed to improve writing skills, that aimed to improve literacy skills of children with an autism spectrum disorder and studies that focused only on assessment or description of literacy skills were excluded.
Interventions included targeting single literacy skills (such as sight word vocabulary), increasing the frequency, variety or complexity of AAC messages during literary activities and letter-sound correspondence. Intervention procedures and strategies are reported in detail in the text. Participants ranged in age from two to 14 years; most were between three and seven years old. The proportion of females was 61%. Most participants were described as having multiple disabilities or genetic syndromes commonly associated with intellectual disability.
Three reviewers independently selected studies for inclusion. Disagreements were resolved through discussion.