Sensitivity of Screening Toddlers At Risk of Autism Spectrum Disorders Using M-CHAT Through Mandatory Health Checkups At 18 and 36 Months in Japan

Background: Children with autism spectrum disorders (ASD) are known to have varieties of difficulties in their life. Therefore, an effort to detect autism-specific symptoms early and provide children with necessary supports is critical (Robins & Dumont, 2006). Recently, a growing body of literature indicates that children with ASD can be reliably diagnosed as young as age 2 on the basis of various social abnormalities (Kamio, 2009). In Japan, checkups for 18-months-old and 3-year-old toddlers are mandated under the Maternal and Child Health Act starting in 1977, and regional health care centers offer the checkups in the community. In general, checkup areas include physical, dental and language development focusing more on severe/profound disabilities; however, in recent years, many places have started screening milder disabilities such as ASD.

Objectives: The purpose of this study was to examine the sensitivity of screening toddlers with possible ASD using M-CHAT at 18 months by following up the same group of toddlers at 36 months at a regional health care center in Japan.

Methods: This study was a part of an entire cohort study of in a suburban city in Japan. All the 18-months toddlers (N=360) who resided in the city from October 2010 till February 2011 were screened for ASD using the Japanese Version of the Modified Checklist for Autism in Toddlers (M-CHAT) at the mandatory checkup. The same group of toddlers (N=385) came back for the 36-months mandatory checkup from April till August 2012 and were screened using the Pervasive Developmental Disorders Autism Society Japan Rating Scale (PARS: Tani et al., 2009, 2010) for ASD.

Results: Among toddlers who were identified positive for ASD at 18-months, approximately seven percent of them were negative for ASD at 36-months (i.e., false positives), whereas less toddlers were positive for ASD at 36-months for the first time (i.e., false negatives). The authors will add more data at the time of the presentation and present other findings based on the M-CHAT score as well.

Conclusions: In Japan, not many areas introduced the screening of mild disabilities at the mandatory health checkup; therefore, there are not many literatures available that followed up toddlers at risk of ASD longitudinally. The findings may encourage more areas to introduce screeners such as M-CHAT at the mandatory health checkup to intervene toddlers at risk as early as possible.