Autism prodrome 15 of 89
both administrations of the screen) indicated a significant risk for developing autism.
However, sensitivity was poor (18%), indicating that four-fifths of the children
subsequently identified as having ASD in the study population were missed on
screening, although this improved to 38% for the one-stage screening procedure.
Clinically the CHAT’s sensitivity was moderate at best and the findings cannot
support a recommendation for universal population screening (Baird et al., 2000). In
the context of establishing the early prodromal signs of ASD, impairments at 18
months in early emerging social communication behaviors appear to characterize
some but a minority only of cases who go on to have a diagnosis.
Buitelaar and colleagues in the Netherlands developed a screening
instrument (ESAT: Early Screening of Autistic Traits) to identify ASD in 14-month-
old children (Willemsen-Swinkels, Dietz, & van Daalen, 2006). Dietz et al. (2006)
completed screening of 31,724 children at 14 months of age. Health practitioners at a
well-baby clinic appointment administered an initial screen of 4 items (measuring
varied play with toys, readability of emotional expression and sensory abnormalities).
If a child failed 1 or more of the 4 items they were offered a follow-up home visit
where a longer version of the ESAT (14 items that included many social
communication items such as eye contact, response to name etc.) was administered
alongside other developmental assessments. Children who failed 3 or more items of
the 14-item ESAT were invited for a diagnostic evaluation at a mean age of 23
months. The ESAT did identify children with ASD (n = 18) and also children with
language disorder (n = 18) and intellectual disability (n = 13). The items that
discriminated best between children with and without ASD were items assessing early
social communication impairments, including ‘shows interest in people’, ‘smiles
directly’ and ‘reacts when spoken to’. This study has shown that as early as 14 months