Incremental Utility of 24-Month Autism Spectrum Disorder Screening After Negative 18-Month Screening

Abstract

The American Academy of Pediatrics recommends Autism Spectrum Disorder (ASD) screening at 18 and 24 months. However, utility of rescreening at 24 months, after a negative 18-month screening, remains unknown. We identified cases of ASD detected at 24 months after a negative 18-month screening (i.e., Catch-24 group; n = 10) and compared them to toddlers detected by 18-month screening (i.e., Early Diagnosis group; n = 203). Repeated ASD-specific screening at 24 months detected children who were missed at their 18-month screening. Thus, our findings support repeated screening for ASD at both 18 and 24 months in order to maximize identification of toddlers with ASD and other neurodevelopmental disorders who require intervention.

Keywords: 18 Months; 24 Months; Autism Spectrum Disorder; Early identification; M-CHAT; Screening.

Figure 1.

Origins of Early Diagnosis group. Participants screened with the M-CHAT(-R)/F at 18 months only are presented; positive screens on either the initial questionnaire or Follow-Up are shaded in light gray, and those children subsequently diagnosed with ASD (i.e., Early Diagnosis group; n = 203) are shaded in dark gray. Both typically developing children and those diagnosed with a developmental disorder other than ASD are included in the Non-ASD category.

Figure 2.

Origins of Catch-24 group. Participants who screened negative on the M-CHAT(-R)/F at 18 months and were then rescreened at 24 months are presented; those children who screened negative on either the initial questionnaire or Follow-Up at 18 months are shaded in light gray, and those who then screened positive at 24 months on both the initial questionnaire and Follow-Up are presented in medium gray. Of those participants, the children who subsequently received am ASD diagnosis at 24 months (i.e., Catch-24 group, n = 10) are shaded in dark gray. Typically developing children (n = 4) and those diagnosed with a developmental disorder other than ASD are both included in the Non-ASD category.