Caregiver behavioral changes mediate the effects of naturalistic developmental behavioral interventions: Combining evidence from three randomized controlled trials.

Naturalistic developmental behavioral interventions target developmentally appropriate skills in young children with autism spectrum disorders using behavioral techniques in naturalistic interactions. Naturalistic developmental behavioral interventions demonstrate strong empirical support and frequently utilize caregiver training of intervention strategies. However, our understanding of the mechanisms of change linked to naturalistic developmental behavioral interventions remains limited. Based on retrospective, secondary data analyses from three previously conducted randomized controlled trials of caregiver-mediated naturalistic developmental behavioral interventions, this study examined the direct effect of intervention on caregiver naturalistic developmental behavioral intervention strategy use and how caregiver changes mediate intervention effects on children's social communication. A total of 419 videos from 229 dyads consisting of autistic children (M = 32.5 months/ages 1-5 years) and caregivers were included in analyses using the masked ratings of the measure of naturalistic developmental behavioral intervention strategy implementation-caregiver changes (MONSI-CC) and brief observation of social communication change (BOSCC-SC). Using longitudinal mediation analyses, we examined the mediation effect of caregiver behavioral changes on children's outcomes. Results demonstrated a significant intervention effect on changes of caregiver naturalistic developmental behavioral intervention strategy use (MONSI-CC) and of changeds of caregiver strategy use (MONSI-CC) on child social communication change (BOSCC-SC) scores, but no overall total effect of intervention on changes of child social communication (BOSCC-SC). This study demonstrates the mediating role of caregiver behavior on the child intervention response, a first step toward better understanding underlying mechanisms in naturalistic developmental behavioral interventions.Lay AbstractNaturalistic developmental behavioral interventions use behavioral techniques in naturalistic interactions and settings. Naturalistic developmental behavioral interventions also teach caregivers to use strategies to enhance social communication in their children with autism spectrum disorder. Naturalistic developmental behavioral interventions are effective in supporting young autistic children but how naturalistic developmental behavioral interventions work ("underlying mechanisms") is not known yet. Therefore, by applying new instruments to videos already collected from the three previously conducted randomized controlled trials of caregiver-mediated naturalistic developmental behavioral interventions, we examined how caregivers change in their strategy use over the course of intervention and how that relates to changes in social communication in their autistic children. A total of 419 videos from 229 dyads consisting of autistic children (M = 32.5 months/ages 1-5 years) and caregivers were included in analyses using two measures, one for the caregiver behavioral changes (the measure of naturalistic developmental behavioral intervention strategy implementation-caregiver changes [MONSI-CC]), and another for the children's social communication (the brief observation of social communication change [BOSCC-SC]). We found that naturalistic developmental behavioral interventions were effective in leading to increased mastery of caregiver naturalistic developmental behavioral intervention strategy use, which then affected the changes in child's social communication skills. However, we found no direct effect of treatment for child social communication skills. This study highlights the mediating role of caregiver behavior on the child intervention response, supporting the importance of involving caregivers as partners in the intervention for young autistic children.