Strengthening the Effects of Parent-Delivered Early Start Denver Model: A Randomized Controlled Multisite Trial
Objectives: Compare effects of the standard and enhanced versions of P-ESDM on parent skills over the treatment period; examine longitudinal relationships between parent acquisition of ESDM skills and child developmental change .
Methods: A multisite RCT enrolled 48 children ages 12-30 months diagnosed with ASD, without other medical diagnoses, with DQs above 35. Thirty children completed the study, 13 in the standard and 17 in the enhanced group. Both groups received 12 weeks of parent coaching and 12 weeks of follow-up. The ESDM Parent Fidelity Implementation measure and an adapted version of the ESDM Curriculum Checklist were administered and scored 8 times by trained staff naïve to group assignment and hypotheses.
Results: Generalized linear mixed models (GLMM) were used to model longitudinal trajectories of outcomes, with main effects of treatment group and time, treatment by time interactions and subject level random intercepts and slopes. We found a significant interaction effect between treatment group and time on parent fidelity scores (t(160)=3.23; p=0.0015; Enhanced group: Estimated Mean Baseline: 3.28, Estimated Mean at End of Treatment: 3.81; standard group: Estimated Mean Baseline: 3.37,Estimated Mean at End of Treatment: 3.20). Improving parent fidelity scores occurred only in the enhanced ESDM group (See Figure 1)
Using the same GLMM approach, we found that both groups of children showed improvements in child checklist score (t(217)=12.01; p<.0001) (enhanced group: Estimated Mean Baseline: 0.35; Estimated Mean at End of Treatment: 0.51; standard group Estimated Mean Baseline: 0.38, Estimated Mean at End of Treatment: 0.50). Baseline ADOS (β=-.057±.0012 t=-4.65 p<.0001) and Mullen scores (β=.0076±.0015 t=5.18 p<.0001) were significant covariates. Covariates of mother’s education level, age of subject, and average hours of outsideintervention were not significant . Group and time interaction for child change on the checklist was not significant (t(215)=1.55; p=0.122).
To examine relationships between parent and child change, we regressed the GLMM predicted subject-specific checklist slopes on the predicted subject-specific parent fidelity slopes. A significant association was found (β=.051±.015, t=3.35, p=.0021).
Conclusions: Parents in the enhanced P-ESDM demonstrated significantly faster rates of learning and greater fidelity than did parents in standard ESDM. The significant association between parent and child slopes suggests that the children of parents who showed improvement over time (enhanced group) show more rapid improvements on checklist scores over time, than did children whose parents do not show fidelity improvement over time (standard group). However the association between parent and child improvement was not as strong within the standard ESDM and enhanced ESDM groups.