Mieke Dereu

Screening for autism spectrum disorders: state of the art in Europe

A large number of studies have reported on the validity of autism spectrum disorder (ASD) screening procedures. An overall understanding of these studies’ findings cannot be based solely on the level of internal validity of each, since screening instruments might perform differently according to certain factors in different settings. Europe has led the field with the development of the first screening tool and first prospective screening study of autism. This paper seeks to provide an overview of ASD screening studies and ongoing programmes across Europe, and identify variables that have influenced the outcomes of such studies. Results show that, to date, over 70,000 children have been screened in Europe using 18 different screening procedures. Differences among findings across studies have enabled us to identify ten factors that may influence screening results. Although it is impossible to draw firm conclusions as to which screening procedure is most effective, this analysis might facilitate the choice of a screening method that best fits a specific scenario, and this, in turn, may eventually improve early ASD detection procedures.

How useful are screening instruments for toddlers to predict outcome at age 4? General development, language skills, and symptom severity in children with a false positive screen for autism spectrum disorder

Screening instruments for autism spectrum disorder (ASD) often generate many false positives. It is argued that these children may have other developmental difficulties and are also in need of thorough assessment and early intervention. The current study looked at the predictive validity of positive screens on the Checklist for Early Signs of Developmental Disorders (CESDD) and the Early Screening of Autistic Traits questionnaire (ESAT) at age 2 towards language, cognitive function, and symptom severity at age 4. Children who screened positive on the ESAT scored lower for both language and cognitive functioning at age 4 compared with children who screened negative on the ESAT. Also, the more signs of ASD that were recognized on the CESDD or ESAT, the lower the scores for language and cognitive functioning at age 4. False positive screens could be differentiated from true positive screens on the CESDD only in symptom severity score on the Autism Diagnostic Observation Schedule (ADOS). It seems that early screeners for ASD also detect children with other developmental disorders and that diagnostic instruments such as the ADOS are warranted to differentiate between children with ASD and other developmental problems.

Measurement Issues: Building a theoretical framework for autism spectrum disorders screening instruments in Europe

BACKGROUND This study addresses the need for a theoretical base to develop more effective early autism spectrum disorders (ASD) detection tools. The structure that underlies early ASD detection is explored by evaluating the opinions of experts on ASD screening tools currently used in Europe. METHOD A process of face and content validity was performed. First, the best constructs were selected from the relevant tests: Checklist for Early Signs of Developmental Disorders (CESDD), Checklist for Autism in Toddlers (CHAT), Early Screening of Autistic Traits Questionnaire (ESAT), Modified Checklist for Autism in Toddlers (M-CHAT), Social Communication Questionnaire (SCQ) and Communication and Symbolic Behaviour Scales Developmental Profile (CSBS-DP). The diagnostic content validity model by Fehring (1986, 1994) was adapted to make the selection. Afterwards, the items, taken from these tests, were selected to fit into each construct, using the same methodology. RESULTS Twelve of the 18 constructs were selected by the experts and 11 items were chosen from a total of 130, reduced to eight after eliminating tautologies. CONCLUSIONS Mapping these constructs and items on to the DSM-5 diagnostic criteria for ASD indicated good face and content validity. Results of this research will contribute to efforts to improve early ASD screening instruments and identify the key behaviours that experts in ASD see as the most relevant for early detection.