Onset of autism is usually described by two patterns: an early onset when a child shows typical symptoms within the first year of life and a regressive one when a child has a period of apparently tipical development, followed by a lost of communicative and social skills during the second year of life. Recent studies describe a third pattern of onset in which the children demonstrate mild delays during the first year of life followed by later regression.
To describe early development, clinical characteristics of regression and later severity of autistic symptoms in children with different type of onset.
A retrospective measure, the Early Development Questionnaire (EDQ), has been used to collect parent-reported information about social development in the first 18 months of life and regression of skills, in 50 under-six children with a diagnosis of autism or PDD-NOS. Different instrument (ADOS-G, CARS and CBCL) were used to assess symptoms severity.
Based on their EDQ scores the children were divided into three groups: 1) early onset group (n=11); 2) definite regression group (n=15); 3) and a more heterogeneous and less clear regression group (n=24). Early development in children with definite regression results more typical in comparison with the other two groups, with significant differences in many social and communicative skills. Neverthless, 90,9 % of children with certain regression fail in showing two or more expected communicative or social behaviours. No significant differences in the severity of autistic symptoms were found among the three groups.
In a large part of the children with regression, the early development, before the skills’lost, only apparently turns out as typical; these children fail in showing waited social behaviours.