A Randomized Trial of Direct Instruction Language for Learning in Children With Autism Spectrum Disorder.

Objective: To compare Direct Instruction Language for Learning (DI) plus treatment as usual (TAU) with TAU alone in children with autism spectrum disorder and moderate language delay.

Method: In this study, 83 children (age range, 4 years to 7 years 11 months) were randomly assigned to DI+TAU (n = 42) or TAU (n = 41) for 6 months. Trained therapists delivered DI in twice-weekly, 90-minute sessions for 24 weeks. The primary outcome was the standard score on the age-appropriate version of the Clinical Evaluation of Language Fundamentals (CELF). The key secondary measure was the proportion of children rated by a clinician blinded to treatment as "much improved" or "very much improved" on the Clinical Global Impressions-Improvement (CGI-I) scale.

Results: Attrition was 12%. At end point, DI+TAU participants showed a 4.8-point (8.1%) increase on CELF vs 2.3 points (4.1%) in TAU participants (difference = 2.55, p = .14, effect size = 0.25), rendering this a negative trial on the prespecified primary outcome. In post hoc analysis that adjusted for IQ, mean difference was 3.5 (p = .04, effect size = 0.33). On CGI-I, 54.8% (23/42) of DI+TAU participants were rated much improved or very much improved compared with 21.9% (9/41) of TAU participants (χ = 9.4, p = .002). On the clinically meaningful threshold of >5 points on CELF, 55.5% of DI+TAU participants achieved this benchmark vs 29.3% of TAU participants (χ = 3.6, p = .06). Complete CELF data were available for 72 participants. In the combined sample, baseline CELF scores ≤50 were associated with no improvement.

Conclusion: On CELF, DI+TAU did not meet the prespecified difference from TAU. When adjusted for IQ, DI+TAU was superior to TAU on CELF at end point. DI+TAU was superior to TAU on CGI-I.

Clinical Trial Registration Information: Direct Instruction Language for Learning in Autism Spectrum Disorder; https://clinicaltrials.gov/; NCT02483910.