Objectives: To describe the response to the ESAT and M-CHAT and explore overlap and difference in screen-positive children identified with ESAT and M-CHAT. Further, to examine external validity of ESAT and M-CHAT, by exploring relationships with proxy-measures of clinical caseness (in the absence of more final data of children with ASD identified).
Methods: The data have been collected in the context of the Autism Birth Cohort Study, an ongoing, prospective birth cohort study in Norway, funded by the Norwegian Institute of Public Health, and the National Institute of Health of the USA. Mothers of 12,948 18 months old children completed a questionnaire which included items from the ESAT, M-CHAT and other items about their child’s social and emotional development and behaviour.
Results: The percentages screen-positive children on the ESAT (0.5%) and M-CHAT (5.4%) differed significantly from each other (p<.01). Among all children, 94% was screen-negative on both questionnaires, 0.33 % was screen-positive on both, 0.2% was only screen-positive on the ESAT, and 5% was only screen-positive on the M-CHAT. Exploration of the ESAT and M-CHAT in relation to proxy-measures revealed the highest percentage of clinical and developmental concerns for children who were screen-positive on both questionnaires. ESAT only screen-positive children scored relatively high on items of behavioural and temperamental problems. For the M-CHAT only screen positive group there were more concerns about motor development.
Conclusions: Results of this study demonstrated overlap in identified cases by the ESAT and M-CHAT. The questionnaires differed significantly in the percentages of screen-positives. Based on the relationship with proxy-measures, the ESAT tends to pick up children with behavioral problems and emotional distress and the M-CHAT children with more general and motor developmental delays.