The Early Screening for Autism and Communication Disorders (ESAC): Preliminary Field-Testing of An Autism-Specific Screening Tool for Children 12 to 36 Months of Age

Background: There is a critical need for validated screening tools for autism spectrum disorders (ASD) in very young children so that families can access intensive, appropriate intervention services as early as possible. The American Academy of Pediatrics (Johnson & Meyer, 2007) recommended that all children be screened for ASD at 18 and 24 months. However, there are no well-validated screening tools for this age range.

Objectives: The purpose of this study was to examine the utility of a new autism-specific parent report screening tool, the Early Screening for Autism and Communication Disorders (ESAC) to screen for ASD in children between 12 and 36 months of age.Methods: The research edition of the ESAC included 47 recognition format or closed-choice items based on research on early red flags of children with ASD from 12-36 months. It included items from all three DSM IV domains on both the absence of typical milestones and the presence of atypical behaviors. Field-testing for the ESAC was conducted from two sources: 1) a follow-up of 375 children recruited by the FIRST WORDS^® Project with a broadband screener for communication delays from a general population sample of 6,149 children; and 2) 75 children referred for possible ASD to 4 field-test sites in the US. The ESAC was evaluated for the 452 children in 3 age groups: Early 2^nd year (12-17 months, m=15.2, n=136), Late 2^nd year (18-24 months, m=20.5, n=145), and 3^rd year (25-36 months, m=29.6, n=175). A best estimate diagnosis of ASD (n=136), developmental delay in which ASD was ruled out (DD; n=96), or typical development (TD; n=218) was made based on a diagnostic evaluation.

Results: Receiver operating curves (ROC) were examined for the entire 47 items and for a subset of 24 items that best discriminated children with ASD from the nonspectrum groups. The area under the curve for the 47-item and 24-item total scores ranged from .90 to .94 across the 3 age groups. Preliminary cutoffs were established for each age group with sensitivity ranging from .85 to .91, specificity from .82 to .84, PPV from .55 to .81, and NPV from .88 to .98. Moderate to large correlations (r= -.34 to -.54) were observed between the ESAC and nonverbal and verbal developmental quotients on the Mullen Scales of Early Learning. Large correlations (r=.57) were observed between the ESAC and the ADOS. False positives and false negatives were examined in relation to the DSM triad of diagnostic features.

Conclusions: These results provide preliminary support for the validity of the ESAC as an autism-specific screener in children 12-36 months age. These findings add to the research documenting the accuracy of parent report to screen young children. Using a parent report tool, such as the ESAC, minimizes the time required of healthcare providers, maximizes the role of the family, and provides reasonably accurate information about whether to refer a child for a diagnostic evaluation for ASD. These findings offer promise for a cost-effective screener for ASD in the 2^nd and 3^rd years of life.