Document Type : Original Articles


1 Department of Linguistics, faculty of literature, humanities and social Sciences, science and research Branch, Islamic Azad University, Tehran, Iran

2 Department of Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran (Islamic republic of)

3 Department of Department of Linguistics, faculty of humanities, Tarbiat Modarres University, Tehran, Iran



Backgrounds: Many Speech and language pathologists or SLPs are employed by Iran’s ministry of education. The traditional perspective applies a traditional pull-out model to deliver services. However, there are other service delivery models/approaches (SDM) for SLPs to be allied at schools such as: classroom based, & consultant. The advantages of some of these approaches have been confirmed for other countries but Iran. This study aimed to find out which SDM was more effective to elevate language skills in Persian-speaking children with intellectual disability (ID).
Methods: This study was a single-blind randomized controlled trial. Twenty-one preschoolers whose mental age was around 4:6 were divided by classified randomization in three groups (pull-out, classroom-based, & consultant) to receive speech therapy services. All students’ language skills were assessed by an experienced speech therapist through the Persian version of TOLD-P:3 (with favorable content validity and acceptable reliability). The students’ language age on the core subtests and their compositions were compared with the Kruskal-Wallis test.
Results: Comparison of language areas and compositions showed that speech therapy was effective regardless of the delivery service model. However, students in the consultant model showed significant change in their “Grammatical completion” score (p = 0.011), and in the other four composition scores as well: ‘spoken language’ (p = 0.05), ‘organizing’ (p = 0.009), ‘speaking’ (p = 0.017), & ‘syntax’ (p = 0.055).
Conclusion: The present study showed that speech therapy regardless of its SDMs would have effects on language skills of children with ID. However, consultant model was the most effective one compared with the other two models (pull-out and class-room based) for children with ID.