Early detection and stability of diagnosis in autism spectrum disorders

Introduction. Early intervention for children with an autism spectrum disorder (ASD) depends on early and reliable detection. In general, diagnosis is stable, but evidence shows the need to go deeper into the factors that influence this stability. Patients and methods. A sample of 142 children with ASD (118 boys and 24 girls) with a median of 33 months of age and an interquartile range of 12 in the first evaluation. In the follow-up the median was 47 months and an interquartile range of 29. The following tests were applied to evaluate the children: Merrill-Palmer Scale-R, Leitter-R, WIPPSI-III, WISC-R and WISC-IV; as well as Vineland Scale and ADOS-G, based on clinical diagnosis to DSM-IV-R and DSM-5. For the evaluation of the diagnostic stability, contingency tables were performed for diagnostic assessments based on clinical judgment and the results of the ADOS-G. Repeated measures ANOVA was used to analyze the differences between measures of cognitive functioning, adaptive behavior and diagnosis. Results. The clinical diagnosis based on DSM-IV-TR, DSM-5 and clinical judgment remains stable over time in 96% of cases. If the diagnostic stability is measured based on the results of ADOS-G (n = 30), 87% of cases diagnosed maintained the diagnosis. The ANOVA showed statistically significant differences for measures of within-subject factors and global social age, but not for diagnosis. Conclusion. The diagnostic stability can be improved by utilizing clinical judgment and the participation of a multidisciplinary team.