International Meeting for Autism Research (London, May 15-17, 2008): The Continuous STAT: Investigation of a New Coding System for the Screening Tool for Autism in Two-Year-Olds (STAT)

The Continuous STAT: Investigation of a New Coding System for the Screening Tool for Autism in Two-Year-Olds (STAT)

Saturday, May 17, 2008
Champagne Terrace/Bordeaux (Novotel London West)
10:30 AM
C. R. McMahon , Psychology & Human Development, Vanderbilt University, Nashville, TN
B. Thompson , Pharmacology, Vanderbilt University, Nashville, TN
W. Stone , Vanderbilt Children's Hospital, Vanderbilt University, Nashville, TN
Background: The STAT is an interactive measure for identifying children at risk for autism (Stone, Coonrod, & Ousley, 2000; Stone, et al., 2004).  A scoring algorithm for 24-36 month olds has demonstrated strong psychometric properties for discriminating autism from developmental delay (DD).  Modifying the existing STAT scoring algorithm to make finer discriminations of social-communicative functioning within the autism spectrum (e.g., autism vs. PDD-NOS) may increase the utility of the STAT.

Objectives: To design a more sensitive coding system and scoring algorithm for the STAT for use with toddlers with developmental concerns.

Methods: Videotapes from 11 children with ASD (7 autism, 4 PDD-NOS) and 11 children with DD during the STAT were coded.  Children were matched on CA (Mean: 32.7 months; Range: 29-35 months) and MA (Mean: 20.6 months; Range:13.5-30.25).  The Continuous STAT differs from the STAT in that it provides separate scores for social engagement and task performance for each item; each score ranges from 0-2, rather than having a single dichotomous pass/fail score for each item. Item scores are averaged per domain (i.e., play, requesting, directing attention, and imitation) and summed to create “Social” and “Response to Press” (RTP) total scores.  Means for the total and domain scores were compared across groups.

Results: Analyses reveal significant differences between the ASD and DD groups on both the Social and RTP scores.  Moreover, children with PDD-NOS differed from children with autism on the Social score.  Significant correlations were found between the two scores and other measures of autism symptomatology.  Interestingly, different patterns of group differences emerged when scores were compared across domains.

Conclusions: This study provides preliminary support for the use of the Continuous STAT coding system and its ability to discriminate between diagnoses within the autism spectrum.