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Re-examining a Breakthrough

A recent report published on-line by Lancet (Pickles et al., 2016) maintains that a parent-mediated intervention for children with autism has produced the first “long-term symptom reduction after a randomized controlled trial of early intervention in autism spectrum disorder” (p. 1; on-line version). The follow-up study examined a range of outcomes for 121 children who participated in a randomized clinical trial of the Preschool Autism Communication Trial (PACT), conducted at three autism centers in the UK. PACT was compared to a group receiving treatment-as-usual. The PACT intervention was undertaken when the children were initially 24-59 months of age and the mean age of the children at the time of the follow-up study that served as the basis for the current report was 10.5 years.

The PACT intervention consisted of “biweekly 2 hour for 6 months followed by monthly booster sessions for 6 months (total 18). Between sessions, families were also asked to do 30 min. of daily home practice.” (Green et al., 2010; p. 2153) The content of the program targeted “core impairments in shared attention, communication, intentionality and pragmatics that are thought to underlie the abnormal developmental and language pathways of children with ASD.” (Green et al., 2010; Appendix, p. 4)

The authors report that at follow-up, children in the PACT group showed a reduction of “autism symptom severity” as measured by the Autism Diagnostic Observation Schedule. Significant treatment-related improvement was reported in “child dyadic communication initiation,” and parent-reported autism symptoms.

To understand this report more fully, it is necessary to review the PACT intervention findings first published in 2010; this was the report of findings of the same trial described above, at the end of the intervention period. In that original report (Green et al., 2010) there were several anomalies; the primary outcome measure was the raw score from the ADOS communication algorithm, although researchers did not follow standard procedure for scoring the algorithm (i.e., converting item scores of ‘3’ to scores of ‘2’ on the algorithm). The scoring procedure was also “modified to improve sensitivity to change,” adjusting for the fact that “children developing words during treatment become liable to increased scores for deviant language” (p. 2154). The significance of these choices is not clear but in any case, the results at the end of the intervention period did not indicate a significant treatment effect with respect to the primary outcome. The authors concluded “we cannot recommend the addition of this PACT intervention to treatment-as-usual for the purpose of reduction in autism symptoms” (p. 2159).

Now fast-forward to the 2016 Lancet report. The authors first reexamined the 2010 results at the endpoint of the intervention (for the children included in the follow-up) using a revised algorithm and a severity score metric (Gotham et al., 2009). (This revised algorithm and severity score have since been incorporated into the release of the ADOS-2.) The outcome of this re-examination was that at the endpoint of the intervention, contrary to what was reported in 2010, there was, in fact, a treatment effect; using the revised algorithm, at the endpoint of the intervention the PACT group showed a significantly greater reduction in autism symptom severity, compared to the treatment-as-usual group.

However, at the time of follow-up, the treatment effect was no longer statistically significant. While the mean autism symptom severity score for the PACT group was still numerically lower at follow-up than the mean score for the treatment-as-usual group, variability within the groups was substantial and the difference no longer reached statistical significance. Despite this equivocal result, the authors state: “The results of our investigation show a treatment effect to reduce autism symptom severity at treatment endpoint, which remained almost 6 years later, giving a clear averaged treatment effect over the total period” (p. 6, 7; on-line version), and conclude “we are now able to support the use of the PACT intervention for reducing symptoms of autism in young children, a revision of our initial view . . .” (p. 8, on-line version).

The point of this commentary is not to dismiss a potentially useful intervention for young children with autism. This study was carefully done and included a good-sized sample. The fact remains that the PACT group did improve and their improvement was relatively stable. Further, the results come from a parent-mediated intervention, which is, as the authors note, “substantially less time intensive . . . in terms of therapist treatment hours” (p. 7), compared to therapist-mediated approaches to treatment. Nonetheless, the convoluted story reflected in the two accounts of the study tempers this reader’s enthusiasm for the results. Some further demonstration of the effects of the PACT intervention will be needed before it meets conventional standards for an evidence-based treatment procedure.

The popular press reported on the release of this paper with the usual inflationary prose:

“A new form of therapy has for the first time been shown to improve the symptoms and behaviour of autistic children, offering a potential breakthrough in care for millions of families.” (Boseley, 2016)

In fact, neither the treatment approach (parent-mediated intervention) nor the target of treatment (shared attention, communication, intentionality and pragmatics) constitutes “a new form of therapy” as both are well-represented in recent research literature. Further, because the results are best described as equivocal, proclaiming even a “potential breakthrough” is somewhat overstated.

The search for early, parent-mediated intervention approaches that equal or exceed the outcomes of more intensive, and expensive, treatments is an important strand of contemporary autism research. Virtually everyone involved hopes a genuine breakthrough of that sort will be found. But that hope is not yet realized.


Boseley, S. (2016, October 25). Study offers potential breakthrough in care of children with autism. The Guardian. Retrieved from https://www.theguardian.com/society/2016/oct/25/autisc-children-therapy-method-potential-breakthrough-care-preschool-autism-communication-trial

Gotham, K., Pickles, A., & Lord, C. (2009). Standardizing ADOS scores for a measure of severity in autism spectrum disorders. Journal of Autism and Developmental Disorders, 39, 693–705. DOI 10.1007/s10803-008-0674-3

Green, J., Charman, T., McConachie, H., Aldred, C., Slonims, V., Howlin, P., . . . PACT Consortium. (2010). Parent-mediated communication-focused treatment in children with autism (PACT): a randomised controlled trial. Lancet, 375: 2152–60. DOI:10.1016/S0140-6736(10)60587-9

Pickles, A., Le Couteur, A., Leadbitter, K., Salomone, E., Cole-Fletcher, R., Tobin, H., . . . Green, J. (2016). Parent-mediated social communication therapy for young children with autism (PACT): long-term follow-up of a randomised controlled trial. The Lancet.

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