Background: Autism is a complex developmental disorder characterised by impairments in reciprocal social interaction, communication and patterns of repetitive or stereotyped behaviour. Varying degrees of severity exist leading to the term “Autism Spectrum Disorder” (ASD). To date there are no comparable prevalence rates across Europe, due to the fact that different methods have been employed to collect data in different countries. Accurate prevalence estimates are important for several reasons, including monitoring trends, studying the burden of disease, determining risk factors, for policy making and health and social care provision. Autism spectrum disorder prevalence estimation has presented complex problems, and many different study protocols exist. Part of the EAHC funded European Autism Information System project was to design a standard protocol to estimate the prevalence of ASD in European Children. This was the European Protocol for Autism Prevalence (EPAP) study. Ireland is the first country in Europe to operationalize the EPAP.
Objectives: The objective of our study “Autism Counts” was to operationalize the EPAP protocol in Ireland, to validate our screening instrument and to estimate the prevalence of ASDs within 3 regions in Ireland, Cork city, Galway city and Waterford city.
Methods: A questionnaire was developed for self-completion by parents of children attending primary schools in the three study locations. This contained the Social Communication Questionnaire (SCQ) a screening instrument used mainly in a clinical setting prior to its use in this study. We screened 8,138 Irish children 6-11 years of age, using national (n = 7951, 98%) and special education (n = 187, 2%) schools in three urban regions Galway, Waterford and Cork as our sampling frame. Demographics, family history and developmental history were also captured. Children who scored about our cut-off (> 12) were re-administered the SCQ. Children whose scores remained high after the second screening who had no previous diagnosis of ASD were referred for further screening
Results: Completed study booklet returns (excluding incomplete data) from parents for eligible children were as follows: national (n = 5433, 68%) special education schools (n = 72, 38%). The distribution of SCQ scores was highly skewed towards lower scores. The median score was 3.0 (M = 4.65, SD = 4.75). There were statistically significant differences in scores by gender (t(5380) = 7.513, p < 0.001); age (F(2, 5457) = 3.582, p = 0.028) and nationality (t(956.017) = - 3.676, p < 0.001). Parents of children who reported diagnosed disorders obtained the highest scores (M = 9.12, SD = 7.73) children with no parent reported developmental difficulties (M = 3.88, SD = 3.78). Children identified for second stage screening were those scoring 12-14 (n = 225, 4%) and over 15 (n = 231, 4%) on the SCQ. The second stage – (referral for further assessment) is now on-going so we do not have definitive results on prevalence at this point. However preliminary results indicate that Irish prevalence rates are approximately 1% of the population. Of those surveyed a further 103 children were identified as requiring further screening. We completed this and are now finalising full assessment and diagnostic reports for 12 children. This will complete prior to Christmas 2014.
Conclusions: This indicates that our rates are similar to previous estimates of prevalence in the USA and the UK. This research is on-going at this time. Our research shows that it is feasible to collect data using the EPAP protocol and that the methodology would be suitable for use in other European countries.