Effect of Project Impact on Social Imitation in Children with ASD: A Randomized Controlled Trial

Background: Children with ASD show deficits in imitation skills, which are especially pronounced in a social-interactive context (Rogers et al., 2003). Research has shown that social imitation during play is related to language, social reciprocity and symbolic play in children with ASD (Ingersoll & Meyer, 2011). Project ImPACT (Ingersoll & Dvortcsak, 2010) is a parent-implemented intervention, focusing on social communication in children with ASD. One of the intervention targets is the increase of social imitation through the use of interactive and behavioural strategies during daily routines. Previous studies have shown positive effects on language and communication (e.g., Ingersoll & Wainer, 2013; Stadnick et al., 2015). Studies on the effect of Project ImPACT on social imitation are lacking. Moreover, as yet no RCT’s have been published.

Objectives: The goal of the present study was to test the effect of Project ImPACT in a community setting on the spontaneous imitation skills of children with ASD.

Methods:

Participants: 29 children between 22 and 49 months (two girls) were recruited through two services for home guidance for children with ASD. Clinical diagnoses were confirmed using the ADOS-2. Participants were randomly assigned to either an ImPACT intervention group (n = 14) or a treatment as usual (TAU) condition (n = 15). The mean age in both groups was 37 months. There was no significant difference in the developmental index on the Mullen between ImPACT (M = 68.54, SD = 21.80) and TAU (M = 61.93, SD = 16.19), t(25) = 0.90, p = .38.

Intervention: Children in the ImPACT group received 18 weekly individual parent training sessions. Children in the TAU condition received regular home guidance, with a frequency of one session every 2-3 weeks, mainly targeting daily living skills.

Procedure: Imitation skills were assessed with the spontaneous imitation task (Ingersoll, 2008) before and after receiving Project ImPACT (M = after 5.86 months, SD = 1.23) or after a similar time interval (M = 5.60 months, SD = 0.74) in the TAU group. Administrators were blind for group assignment. Imitation skills were coded afterwards from video by coders who were blind for group assignment and testing moment.

Results: A repeated measures ANOVA showed no main effect of time, F(1,27) = 2.03, p = .17. However, there was a significant time*group interaction, F(1,27) = 4.29, p = .048, ηp2 = .14. Children in the ImPACT group showed a marginally significant improvement in their imitation skills from pre (M = 5.64, SD = 3.20) to post intervention (M = 8.71, SD = 5.66), t(13) = 2.11, p = .055, while children in the TAU group did not show this improvement from pre (M = 6.00, SD = 4.39) to post intervention (M = 5.43, SD = 4.07), t(14) = 0.56, p = .59.

Conclusions: Project ImPACT seems to improve social imitation skills of children with ASD through parent training. This is an important finding, given the association of imitation with other social-communicative skills. Results on a larger sample, including follow-up data will be presented at the meeting.