The Modified - Checklist for Autism in Toddlers (M-CHAT): Early detection of autism spectrum disorders

Autism and pervasive developmental disorders, severe disorders of development, are difficult to detect in very young children. However, children who receive early intervention have improved long-term prognoses. Therefore, early identification is critical. A brief screen, appropriate for use in a physician\u27s office, would facilitate early detection of autism spectrum disorders. The Modified - Checklist for Autism in Toddlers (M-CHAT), based on the CHAT (Baron-Cohen, Allen, & Gillberg, 1992), consists of 23 yes/no items. Longitudinal study of the M-CHAT validated the instrument and provided data regarding its psychometric properties. The M-CHAT was used to screen 1293 two-year-old children in Study 1; 39 of the 58 children evaluated were diagnosed with a disorder on the autism spectrum. Six items pertaining to social relatedness and communication were found to have the best discriminability between children diagnosed with and without autism/PDD. Cutoff scores were created for the best items and the total checklist. In Study 2, 537 participants were re-screened two years later, and 26 children who were evaluated in Study 1 were re-evaluated at age 4. Diagnosis remained stable for 69% of the children evaluated, suggesting that diagnosis at two is reliable. Sensitivity, specificity, positive and negative predictive power were calculated; the M-CHAT demonstrates improved sensitivity compared to the original CHAT, without significantly compromising specificity. Although some false positive identifications were made, predictive power remained sufficient. These results suggest that the M-CHAT is successful at identifying autism spectrum disorders at 2 years old. Further study with a larger sample is underway.