Screening for Autism Spectrum Disorders in Medical Checkups At 36 Months Can Predict Later Adaptive Functioning in Nursery School

Background: Early detection and intervention for autism spectrum disorders (ASD) is important because it may lead to better long-term outcomes. In Japan, local governments are legally obliged to conduct a medical checkup for all children whenever they reach the ages of 18 and 36 months. This checkup system is suitable for the detection of ASD because all children receive a checkup regardless of their parents’ knowledge of developmental disorders or socioeconomic status. Nevertheless, the current form of checkups focuses on physical and intellectual development, and most local governments have not yet introduced systematic screening for ASD.

Objectives: We collaborated with a local healthcare center and introduced a systematic screening system for ASD in the medical checkup for 36-month-olds. To assess the validity of the system, we examined whether the screening results could predict later adaptive functioning in nursery school.

Methods: The Pervasive Developmental Disorders Autism Society Japan Rating Scale (PARS) was used for screening. The PARS is an interview-based assessment tool, and it has been previously validated in terms of its ability to discriminate between individuals with ASD and normal controls and in terms of its satisfactory correlation with the Autism Diagnostic Interview-Revised (ADI-R) (Ito et al., 2012). We used the 12-item short form of PARS (Adachi et al., 2008). Health nurses at the local center were trained in using the PARS through lectures from clinical psychologists specialized in developmental disorders. In the first year of the trial, the psychologists and nurses concurrently conducted the PARS, and discrepancies in scoring were resolved through lectures. From the second year, health nurses individually conducted the PARS. The present study used data from the second year. One year later, the children’s adaptive functioning in nursery school was rated by their nursery teachers, using the Nursery Teacher’s Rating Developmental Scale for Children (NDSC). We obtained complete data from 287 children (150 boys). The study protocol was approved by the institutional review board of the Hamamatsu University School of Medicine, and it complies with the guiding policies and principles for experimental procedures endorsed by the National Institutes of Health. There is no conflict of interest.

Results: The PARS score correlated with scores on the NDSC subscales, especially the Communication (r = -.53), Sociality (r = -.39), Attention (r = -.40), Self-care (r = -.39), and Gross Motor (r = -.36) subscales. Children who had scored above the cut-off on the PARS were found to have a high risk (40.9–59.1%) of low adaptive functioning (below the 10th percentile) as per these NDSC subscales. Relative risk ranged from 10.19 to 11.18.

Conclusions: We found that screening for ASD in a medical checkup at 36 months, which is conducted by a health nurse, can effectively predict later adaptive functioning in nursery school.