Title

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

Date of Completion

January 2002

Keywords

Psychology, Clinical|Psychology, Psychometrics

Degree

Ph.D.

Abstract

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's 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. ^