Analysis of Autism Diagnostic Observation Schedule (ADOS) Applied to Chilean Children with Suspicion of Autism Spectrum Disorder (ASD)

Background: The increasing prevalence of ASD in developed countries has been well documented. However, lack of knowledge is reported with regards to the prevalence of this condition in developing countries, with the consequent unawareness of the global variation of these disorders (Germain et al. 2015). In our clinical practice in a Chilean child Neuropsychiatry service, increasing prevalence has been noticed in the last decade. Great importance has been given to the adjustment of our diagnostic tools for timely treatment, considering that the diagnosis and early intervention improves prognosis in these patients (Zwaigenbaum et al., 2015). The Autism Diagnostic Observation Schedule (ADOS) is considered one of the “gold standards” in the diagnosis and research of ASD, determining severity and helping to plan the intervention. Studying a sample of patients under control with this tool will allow us to contrast Chile´s reality with the rest of the world.

Objectives: To evaluate the characteristics of a representative sample of Chilean patients with suspicion of ASD by using the ADOS, and compare the results with those reported in international publications.

Methods: Observational retrospective study of patients with suspicion of ASD, tested with ADOS in a Neuropsychiatry service of a Chilean Public Hospital. 108 children were included, between 1 and 15 years (average age=5.79, median=4). Patients were separated by age and range of severity and the results were analyzed statistically.

Results: Of the 108 children who were tested with ADOS, 88% met criteria for ASD, while 13 did not qualify as ASD (12.0%). Severity: In all, 6.6% had minimal evidence, 9.4% had mild ASD, 4.7% had moderate ASD, 5.6% had mild autism, 34.5% had moderate autism and 23,6% had severe autism. Age: In the sample composed by infant, toddler, preschoolers and schoolchildren, 58% were diagnosed with ASD. In the adolescent group, 54% were autistic. Among the patients that met ADOS criteria for ASD, children between 0 and 5 years graded 2.87 points higher in social affectation than children with ages between 6 to 15 years (p=0.00886). Non-significant differences were found in restricted and repetitive behaviors between different age groups (p=0.519)

Conclusions: Although the diagnosis of ASD is clinical, the ADOS relates to a useful diagnostic tool in the clinical practice, which allows determining severity and make valid comparisons between different populations. Our study confirmed the diagnosis in 88% of patients with suspicions of ASD, a reality in accordance with the data reported in international literature (Molloy et al. 2011).