The term Autism Spectrum Disorder (ASD) has been introduced to reflect the heterogeneity in presentation of disorders previously assigned to discrete diagnostic terms (e.g., Autistic Disorder, Asperger’s Syndrome, Pervasive Developmental Disorder - Not Otherwise Specified; Diagnostic and Statistical Manual of Mental Disorders, DSM-IV, DSM-5). Despite our understanding of the diversity in presentation of ASD, response to intervention has typically been evaluated in terms of overall improvement in treatment groups. It seems likely, however, that just as presentation differs between individuals, so too does response to intervention. Consistent with this perspective is the finding that a significant proportion of children who undertake early intervention do not make noticeable skill improvement (Bent & Hendren, 2010; Seltzer, Krauss, Shattuck, Orsmond et al., 2003; Goin-Koechel et al., 2007; Smith, 1999); in contrast, individuals who have received no intervention sometimes show gains consistent with those seen in treatment groups (Howlin, Magiati, & Charman, 2009). Our study aimed to identify clinically relevant behaviours and possibly phenotypes that might be indicative of better outcomes to treatment.
Our aim was to identify early behaviours that may be pivotal in determining response to treatment. These behaviours consisted of (a) “negative” symptomatology; the absence of which might undermine “typical” development (e.g., lack of shared enjoyment, social reciprocity, imitation and play) and (b) “positive” symptomatology (e.g., sensory sensitivity, stereotypical behaviours, jargon, gaze avoidance), the presence of which might do likewise.
We examined this issue in the context of an on-campus, early behavioural intervention research program for infants with an ASD. In this study we used pre- and post-intervention behavioural measures to identify characteristics of children who varied in their response to an early intervention program. Data from 189 children were available for the analyses at the first three data points (0 weeks, 2 weeks, 18 weeks). Children were exposed to an applied behavior analysis (ABA) intervention program, with behavioural measures obtained pre-intervention, two weeks into intervention and 18 weeks after completion of clinic-based intervention. Children were then followed up after 2 years of independent intervention.
It was clear that for some children the response to intervention was far more positive than for others. Initial presentation was a meaningful indicator of the likelihood of response to intervention as indexed by measures of adaptive functioning (e.g., Childhood Rating Scale, Vineland Adaptive Behaviour Scale). Overall, these results suggest that early behavioural presentation can be used as a predictor of response to early intervention among children with autism. The behaviours pivotal to outcome and the possible interaction between positive and negative symptomatology are discussed.
It is apparent that the absence of some behaviours undermines successful intervention using ABA techniques. Further, other symptomatology may interfere with typical development and reduce the likelihood of success. Intervention programs should focus on the specifics of these behaviours rather than the traditional focus on group outcomes. Successful sub-typing of individuals in terms of likely response to intervention has the potential to enable caregivers to make informed decisions about suitability an intervention program.
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