Accurate Autism Screening at the 18-Month Well-Child Visit Requires Different Strategies than at 24 Months

Area of Science:

• Developmental Pediatrics
• Child Psychology
• Early Childhood Intervention

Background:

• Early identification of Autism Spectrum Disorder (ASD) is crucial for timely intervention and improved outcomes.
• The Modified Checklist for Autism in Toddlers (M-CHAT) and its follow-up interview (M-CHAT/F) are widely used screening tools.
• Screening accuracy can vary based on child's age at the time of assessment.

Purpose of the Study:

• To compare the accuracy of autism screening using the M-CHAT/F at 18 months versus 24 months of age.
• To identify factors that influence the positive predictive value (PPV) of the M-CHAT/F in a community sample.
• To develop an age-based algorithm to enhance screening accuracy in younger toddlers.

Main Methods:

• A community sample of 98 toddlers who screened positive on the M-CHAT underwent formal ASD diagnostic testing.
• The positive predictive value (PPV) of the M-CHAT and M-CHAT/F was calculated for different age groups (<20 months and 20+ months).
• Multivariate analyses examined the contribution of various developmental measures (ASQ, CDI) and M-CHAT/F components to screening accuracy.

Main Results:

• The M-CHAT/F demonstrated a higher PPV (0.58) compared to the M-CHAT alone (0.40).
• The M-CHAT/F achieved a higher PPV (0.69) in children aged 20 months and older, compared to younger children (<20 months, PPV=0.36).
• Language development variables were identified as the most significant predictors for improving PPV in younger toddlers.

Conclusions:

• The M-CHAT/F is a more accurate autism screening tool than the M-CHAT alone.
• Age is a significant factor influencing the M-CHAT/F's predictive accuracy, with older toddlers yielding better results.
• An age-based algorithm incorporating language variables holds promise for enhancing early autism detection in toddlers under 20 months.