Autism and developmental profiles in preschoolers: stability and change over time.

AIM: Increasing numbers of young children are now being diagnosed with autism spectrum disorder (ASD). This study aimed to analyse developmental trajectories in a representative group of preschool children with ASD.
METHOD: In a naturalistic study, 208 preschool children with different subtypes of ASD were followed over a 2-year period. Their trajectories, as regards persistence of ASD diagnoses, developmental/intellectual levels, adaptive functioning and expressive speech, were monitored.
RESULTS: Developmental profiles showed considerable change over time, especially in children with atypical autism and in those with developmental delay/borderline intellectual functioning at their first assessment. Approximately 50% of the children were found to have intellectual disability (ID) at follow-up and, of these, the majority had severe ID. This was in contrast to the first assessment by the referral team when ID had rarely been mentioned or discussed.
CONCLUSION: Changes in developmental profiles during preschool years are common in children with ASD. This implies that reassessments, covering different developmental areas, are needed. Such follow-up assessments prior to the start of school will yield a more valid estimation of the child's general cognitive level and a more accurate ASD diagnosis and thus form a better basis for realistic educational planning and intervention. ©2013 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.