The primary goal of this study was to determine if an intervention that taught parents to follow their toddlers’ interest in topics and maintain this interest could improve their toddlers’ social communication outcomes. A major finding was that caregivers implemented the intervention with a high degree of fidelity and helped their toddlers move from primarily object-focused engagement to increased levels of joint engagement between people and objects. Moreover, parents were able to help their children improve in their responding to joint attention and in the diversity of their play. The IT group outperformed the WL group on the majority of primary outcome measures, with generally large effect sizes. These data highlight the importance of joint engagement as a platform for improving child joint attention and play skills.
The two other high-dose studies of direct teaching of parents to improve joint attention in their children with autism (Rocha et al. 2007
; Schertz and Odom 2007
), both using single subject designs, reported an intervention effect on responding to joint attention. One of the two interventions only taught responding to joint attention (rather than initiating) and all three children improved with intervention and 2 out of the 3 children maintained their skill at a 3 month follow up (Rocha et al. 2007
). The other study achieved better responding skills than initiating skills in toddlers, even though initiating skills were directly taught (Schertz and Odom 2007
). In the current study, initiations also did not improve significantly although they were directly targeted. Taken together, these findings suggest that initiating joint attention skills may be particularly difficult for children with autism to learn, and perhaps also for parents to develop in their children. These findings are in contrast to our earlier intervention, which was therapist-mediated and delivered more densely (an every-day intervention) (Kasari et al. 2006
). Perhaps the expertise of trained clinicians made it possible to achieve changes in initiations, in contrast with the caregiver-mediated model used in this study. On the other hand, an alternate reason for the difference may be the younger age of the children in this study as compared to Kasari et al. (2006
) and the possibility that toddlers were ready to learn responding skills, but not yet ready to initiate joint attention skills. Initiating joint attention skills are generally more difficult to demonstrate for children with autism, and likely need longer and more intense interventions (Mundy et al. 1986
A second main finding was the importance of looking at multiple caregiver factors that could affect treatment outcome. The goal for caregiver-mediated interventions is to increase density of intervention by having parents trained so they can deliver the intervention to their child over the course of every day. If parents do not buy into the intervention or the intervention is too difficult to implement, parents likely will not achieve high fidelity of implementation or adhere to the treatment techniques when on their own. Treatment fidelity has been a longstanding concern with studies finding that when individuals implement interventions with a high degree of fidelity they achieve better treatment success (e.g., Moncher and Prinz 1991
). In this study, all parents were able to implement the treatment with high fidelity, and, perhaps due to a restricted range, fidelity was not associated with outcome. However, even with high fidelity, caregivers may not achieve an optimal density of delivery of the intervention, thus reducing the effects of the intervention. In this study, we asked caregivers weekly for feedback on their ability to carry out the intervention, and to tell us how well the intervention strategies fit into their lives. These caregiver self-reports of adherence and competence in delivering the intervention were also high on average, but of course, respondent bias cannot be ruled out (e.g., the demand characteristics of reporting on use of techniques to the study team that taught them could have inflated reports of usage). Thus, these data did not differentiate between caregivers and children who had better or poorer treatment outcomes.
The quality of caregiver involvement in the intervention as rated by the interventionist did predict child outcomes. This measure differentiated caregiver–child joint engagement at the end of treatment, with higher quality of involvement associated with greater joint engagement and less child object-only focused engagement. Thus, even with high fidelity to treatment, and self-reported adherence to the treatment goals, the quality of involvement varied for caregivers, and these differences were associated with an important aspect of child outcome in this study.
Findings for service utilization were nonsignificant. In autism treatment research, a concern is whether children and parents are involved in other treatments and if the dose or content of these interventions are consistent with the goals of the intervention under study. For example, a parent could be learning to deliver a behavioral treatment that is very structured and adult-driven in the home, which could potentially be at odds with an intervention that teaches the parent to engage in a developmental and relationship-based technique. Thus, it is critical that research studies measure dose and type of these additional services. In the current study, toddlers were involved in early intervention, ranging from 9 to 40 hours per week, with no differences between IT and WL groups in dose and types of early intervention services. The services involved mostly ABA/educational services, and speech and occupational therapy. The current treatment study did not coordinate with the child’s service providers and we may have used both an approach and a focus on skills (e.g. joint attention and play) that were quite different from community intervention programs. However, type and amount of additional services did not seem to affect our experimental treatment effects. Future studies might consider whether parent belief in or preference for a particular approach strengthens or lessens the effects of an experimental intervention.
These data, while limited by a small sample size, are promising since they suggest that positive changes can be made in core deficits in young children with autism when intervention is mediated through parents and conducted over an 8-week period. These are among the first randomized controlled data suggesting that a caregiver-mediated intervention can improve aspects of child engagement, joint attention and play skills in toddlers with autism. Most models of early intervention for children with ASD continue to focus exclusively on therapist-mediated models of intervention. Whether a parent mediated model is as effective as a therapist delivered model for toddlers with autism has not been tested. This issue is significant and worthy of further attention since a parent mediated model may prove to be a cost effective way to widely disseminate effective interventions to young children with ASD.