Overview
- The multi-site retrospective analysis, published in the Journal of Clinical Child & Adolescent Psychology, pooled child-level data from 707 preschoolers who received 6–24 months of evidence-based services at 10 or more hours per week.
- Among 293 children who were non-speaking at baseline, roughly two-thirds progressed to using single words or more, while about one-third remained non-speaking after intervention.
- Intervention model—Early Start Denver Model, Naturalistic Developmental Behavioral Interventions, Early Intensive Behavioral Intervention, or TEACCH—did not predict spoken-language outcomes in the primary sample of 470 children or in the non-speaking subgroup.
- Poorer progress was associated with greater autism severity, lower adaptive and cognitive functioning, and weaker motor imitation, with non-progressors tending to start later and receive shorter-duration services despite higher weekly intensity.
- Authors call for individualized planning, prospective tests of earlier access and longer duration targeting prelinguistic skills, and timely use of augmentative and alternative communication when speech gains are limited; they caution that slightly younger average start ages among some non-progressors likely reflect developmental readiness rather than inefficacy of early intervention.