Stability of early daignosis in autism spectrum disorders

Background: Early diagnosis of autism in toddlers now is possible after recently vigorous investigation. However the stability of diagnosis in younger children with autism spectrum disorders (ASD) still need further researches.

Objectives: We tried to assess the stability of clinical diagnosis of ASD in Taiwanese toddlers when followed up 18- 21 months later.
Methods: We recruited 31 children aged between 24-36 months (male: female= 23: 8, with mean age=29.4 months, and mean mental age=17.5 months) from the Developmental Assessment Clinic of the Chiayi Christian Hospital, with the consent of their parents. Initially (time 1) two child psychiatrists made the clinical diagnosis by the DSM-IV diagnostic criteria of pervasive developmental disorders through interaction with children and semi-structure interview with their caregivers. 18- 21 months later (time 2) we made final diagnoses for all those children after the same diagnostic procedures and consensus meetings. Children with evident neurological disorder or sensory deficit were excluded.

Results: At time 1, according to the initial diagnosis, those children were divided into autism group (N=12), PDDNOS group (N=6), and developmental delayed group (N=13). At time 2, for the autism group, nine children still had the diagnosis of autism, and one PDDNOS and two delayed; for PDDNOS group, one child had had changed diagnosis of autism, four still PDDNOS and one delayed; and for delayed group, none had autism, two children PDDNOS and 11 still delayed.

Conclusions: Our findings confirmed the possibility of early diagnosis of autism in children younger than 3 years old. And at our follow up study, the clinical diagnosis of either ASD or delayed group was quite stable. Further studies with larger sample size are needed.