Measuring Emerging Changes in Social Communication

Background:  Clinical trials testing the effectiveness of medical treatments on the behaviors of children with ASD have typically used parent questionnaires and clinician judgments heavily reliant on caregiver reports to measure outcomes.  Using these measures, a number of approaches to decreasing behavior problems have been shown to be effective.  Changes in response to behavioral clinical trials have typically been most evident for measures of general development and parent report measures of adaptive functioning.  There has been much interest in measuring the effects of interventions on core features of autism.  Several parent-report instruments have been proposed to fill these gaps.  The advantage of observational measures, such as the ADOS, is that raters can remain truly blind to intervention status.  However, though long-term changes in social-communication have been documented using calibrated scores from the Autism Diagnostic Observation Scale (ADOS), in general, the ADOS has not shown much effect of intervention.  Other limitations include substantial correlations with verbal IQ; ADOS calibrated severity scores reduce these correlations, but result in children’s scores being compared to other children of the same age and language level, which may underestimate the amount of change.   

Objectives:   To design and test a standardized observational method of measuring change in core features of ASD that can be used by different research projects employing different contexts for these observations and that allows independent, blind scoring of change in response to behavioral interventions.

Methods:   The ADOS-C (ADOS-Change) provides a way of describing change in autism-specific social communication deficits.  Standard 6 point codes for 15 social-communication behaviors are rated from a videotaped 10 minute interaction.  Inter-rater and test-retest reliability have been established. Rather than contrasting scores of an individual child to normative scores from other children, the ADOS-C compares total scores of the same child in the same context at different times.  Multiple raters are currently coding data for over 100 children between the ages of 18 months to 3 years at at least three points: pre-intervention, post-intervention and follow-up from randomized controlled trials of three different early interventions and one multiple baseline study.  These studies ranged greatly in length and intensity of treatment; all contexts were “natural” play during mother-child interactions.

Results:  For several, but not all interventions, preliminary analyses of the ADOS-C showed changes when the ADOS did not.  Illustrative data will be presented. Clinical validity of the measure was also tested by comparing scores from children nominated by therapists and those reported by parents as showing the least and greatest amount of change in behavior.  Factors associated with changes were complex and have implications for research designs and for use of observational methods documenting changes in social-communication behaviors.

Conclusions: The potential to provide truly independent measures of more subtle changes in core features of ASD, as well as methodological issues for the ADOS-C and other measures of change in these features will be discussed, particularly in terms of planning and interpreting results of intervention studies.