Evaluating the Pragmatic Rating Scale-School Age: Robust Psychometrics and Clinical Implications

Poster Presentation
Friday, May 3, 2019: 11:30 AM-1:30 PM
Room: 710 (Palais des congres de Montreal)
E. F. Dillon1, K. J. Greenslade2, E. Utter3 and R. Landa1, (1)Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD, (2)Kennedy Krieger Institute, Baltimore, MD, (3)Kennedy Krieger Center, Center for Autism and Related Disorders, Baltimore, MD
Background: Pragmatic, or social communication, deficits are key characteristics of autism spectrum disorder (ASD); subclinical differences are detectable in first degree relatives of individuals with ASD (Landa, 1992; Greenslade et al., in press). Two main types of pragmatic language measures exist: parent report and standardized structured clinician-administered assessments. Both have limitations. Parent–rated may be less sensitive than clinician-rated measures (Hess & Landa, 2012) and structured measures lack ecological validity. To provide a clinician-rated measure based on ecologically valid communication samples, the Pragmatic Rating Scale-School Age (PRS-SA; Landa, unpublished) was developed. The PRS-SA enables clinicians to rate level of social difficulty (0=none, 3= severe) across 21 components of communication.

Objectives: To evaluate the internal consistency and concurrent validity of the PRS-SA in 4- to 8-year-olds with a continuum of ASD symptomatology, and preliminarily examine whether the PRS-SA is useful for detecting ASD symptoms and risk. Hypothesis: The PRS-SA will demonstrate: (1) moderate internal consistency due to the diversity of social language and communication features measured; (2) strong correlation (concurrent validity) with standard ASD measures, as pragmatic impairment is central to ASD; and (3) good sensitivity and specificity for ASD classification (positive/negative).

Methods: 136 4- to 8-year-olds (M=6.94 years, SD=1.85) (83 males; n=49 with ASD) at high and low risk for ASD participated in a prospective, longitudinal study of ASD (additional data will be added by the INSAR presentation). All had complete data on the Abbreviated Stanford Binet Intelligence Scale, 5th Edition, ADOS-2, SRS-2, and PRS-SA. Cronbach’s alpha examined internal consistency. Pearson’s correlation coefficients assessed PRS-SA criterion validity (concurrent) with the SRS-2 and ADOS-2 (standardized ASD assessments). A receiver operating curve (ROC) analysis was conducted to examine PRS-SA sensitivity and specificity for identifying ASD+ or ASD- status (Figure 1).

Results: Cronbach’s alpha (α=.635) indicated a moderate level of internal consistency, and no improvements were noted with the removal of any individual item. PRS-SA total score was significantly correlated with SRS-2 total score (r=.453, p=.002) and ADOS-2 Communication domain algorithm score (r=.424, p<.001).

ROC analysis generated an AUC of .890, indicating a good level of sensitivity and specificity for identifying ASD status. A PRS-SA cut off score of 21 is optimal for identifying ASD+/ASD- status: sensitivity=.837, specificity=.790.

Conclusions: As hypothesized, the PRS-SA demonstrated moderate internal consistency, likely reflecting the diversity of communication behavior encompasses in pragmatics and measured by the PRS-SA. Factor analysis will explore potential subscales when sample size is increased, and will be reported in this presentation. Strong correlations between PRS-SA total score and two standardized mainstream ASD measures (one a parent report and one a clinician-rated, direct observation), provide strong concurrent validity evidence, affirming the PRS-SA’s use to detect ASD-related pragmatic communication behavior. Our findings suggest that PRS-SA scores of ≥21 in 4- to 8-year-olds indicate the need for ASD evaluation. Additional recruitment will allow a validation of this cut off score in an independent confirmatory sample; sensitivity and specificity results from this analysis will be reported.