Development of T-STAT for Autism Spectrum Disorder Screening Under 2 Years Old

Background: Prevalence of autism spectrum disorder (ASD) has increased markedly. Previous studies reported that early intervention improved outcomes for toddlers with ASD (Dawson et al., 2010; Landa et al., 2011). The benefits of early intervention highlighted the importance of earlier identification of toddlers with ASD. Due to the importance of early identification, the American Academy of Pediatrics has recommended that all infants receive universal screening for autism less than 24 months old (Johnson et al., 2007). However, the diagnosis of ASD is still often delayed because diverse factors, including limitations in utility of screening instruments etc. There are few level 2 screening tools to distinguish ASD from other developmental disorders for toddlers before 24 months.

Objectives: The current research, there are two studies to test utility of using the Screening Tools for Autism in Two-Year-Olds, Taiwan version (T-STAT) (Chiang et al., 2012) for toddlers with autism spectrum disorders (ASD) from 18 to 24 months of age.

Methods: The T-STAT is a 12 items interactive autism-specific screening tool, including four behavioral domains: play (2 items), requesting (2 items), joint attention (4 items) and imitation (4 items). Within both play and requesting, if a toddler fails one item, he would receive a score of 0.50. Within both joint attention and imitation, if a toddler fails one item, he would receive a score of 0.25. The scores of four domains are from 0 to 1. The scores of four domains are summed, obtaining a total T-STAT scores which from 0 to 4.

Results: Study 1, there are 32 toddlers, including 16 toddlers with ASD and 16 toddlers with developmental delayed (DD). A diagnosis of ASD by a research team based on the DSM-5 criteria (Frazier et al., 2012). Using signal detection procedures, the optimal cutoff of the total T-STAT score was decided. The results revealed that 2.5 was the best cutoff, the sensitivity and specificity are 1.00 and 1.00, respectively. Study 2, there are 137 toddlers, including 62 toddlers with ASD and 75 toddlers with DD. Using the 2.25 as cutoff, the sensitivity and specificity were .92 and .80, respectively. In addition, PPV is .84 and NPV is .92. Using the 2.50 as cutoff, the sensitivity and specificity were .89 and .84, respectively. In addition, PPV is .80 and NPV is .92.

Conclusions: The T-STAT is a promising good tool to differentiate the toddlers with ASD and toddlers with DD.