Eligible studies had to have at least one child participant with an autism spectrum diagnosis. The main intervention had to involve at least one of four identified milieu therapy techniques described in the paper. The desired outcome needed to focus on increased communication.
In the included studies, 74% of the participants were male. Children ranged in age from 2.9 to 15.8 years (average 7.3 years). Mental and language age were not reported consistently across the studies. All participants had a diagnosis of autism. Prior speech levels varied. Most studies were conducted in the child's natural environment (home or community setting). One study was in a clinic arranged as a classroom and a further study was in a playroom in a university setting. Teachers, paraprofessionals and parents conducted the most of the interventions. Various target communication behaviours were addressed for basic needs, emotion phrases, descriptive phrases, pairs of prepositions, questions, receptive labelling and increased mean length of utterance.
The author did not state how many reviewers were involved in the selection of studies for the review.