Evaluation of regression in autism spectrum disorder based on parental reports

BACKGROUND: Research indicates that some children with autism spectrum disorder (ASD) experience a developmental regression. AIMS: The study examined the percentage of children with autism, pervasive developmental disorder (PDD), ASD, and Asperger syndrome (AS) who were considered to be delayed (D), regressed (R), or delayed and later regressed (DR) and examined any relationship with autism severity, time of onset, factors associated with onset, gastrointestinal (GI) symptoms, race, age, and gender. MATERIALS AND METHODS: The study reviewed developmental and medical information based on parental reports of 135 children with a diagnosis of autism, PDD, ASD, or AS. RESULTS: The number of children in the D group was 53 (39.2%) with 19 (14.1%) in the DR group and 63 (46.7%) in the R group. Thus, 82 children (60.7%) were reported to have R. In regard to onset of symptoms, there was a significant difference between the D and R groups as well as between the DR and R groups. The analyses showed that there was no significant relationship between age, gender, race, severity, or GI symptoms and membership in any group; D, DR, or R. The majority of parents reported that the regression was preceded by or was associated with vaccinations (57.3%) or another medically related event (11.0%). CONCLUSIONS: The findings are consistent with previous research and reinforce our understanding of regression in those children with an ASD diagnosis.