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Using the Quantitative Checklist for Autism in Toddlers (Q-CHAT) At 24 Months to Predict ASD Diagnosis At 36 Months

Thursday, 2 May 2013: 09:00-13:00
Banquet Hall (Kursaal Centre)
G. Pasco1, K. Hudry2, S. Chandler1, C. Allison3, S. Baron-Cohen3, M. Elsabbagh4, M. H. Johnson5 and T. Charman1, (1)Centre for Research in Autism & Education, Institute of Education, London, United Kingdom, (2)Olga Tennison Autism Research Centre, School of Psychological Science, La Trobe University, Bundoora, Australia, (3)Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, (4)Department of Psychiatry, McGill University, Montreal, QC, Canada, (5)Centre for Brain & Cognitive Development, Birkbeck, University of London, London, United Kingdom

The British Autism Study of Infant Siblings (BASIS) is a longitudinal study involving participants with older siblings with a diagnosis of ASD (high-risk sibs) and controls with no older siblings with ASD (low-risk sibs). Participants were assessed at 6, 12, 24 and 36 months, using a range of standardised, observational and questionnaire measures. The Quantitative Checklist for Autism in Toddlers (Q-CHAT) is a normally-distributed 25-item questionnaire designed to be completed by caregivers of children at approximately 18 to 24 months. Scores for each item range from 0 to 4, with higher scores representing a greater level of traits associated with the autism spectrum. Total scores are calculated by summing scores from all items.


To investigate the predictive validity of administering the Q-CHAT at 24 months in a high-risk sample and to identify Q-CHAT items that may function as red flags for autism.


The Q-CHAT was completed by parents of high-risk (N=49) and low-risk (N=47) participants just prior to the 24-month assessment (mean 23.9 months, SD 1.0). Following the 36-month assessment (mean 37.9 months, SD 3.1) children in the high-risk group were assigned to one of three subgroups based on a best estimate clinical diagnosis: Typically developing (Sib-TD; N=23); ASD (Sib-ASD; N=15); and Other concerns(Sib-Other; N=12) – children who appeared to have some developmental difficulties but who did not meet criteria for ASD.


There was no significant difference between the Q-CHAT total scores of the high- and low-risk groups (t=-1.48, p=0.14). Total scores of the Sib-ASD group were significantly higher than those of Sib-TD (p<0.01) and Sib-Other (p<.05) subgroups and the low-risk group (p<.01), but there were no differences between the three non-ASD groups. Individual items with scores of “3” or “4” in more than 25% of each subgroup were identified. Seven items were identified from the Sib-ASD group, relating to echolalia (73%); using another’s hand as a tool (67%); repetitive behaviour (47%); offering comfort (33%); lining up objects (27%); staring at a spinning object (27%); and sniffing or licking unusual objects (27%). The echolalia item was endorsed by 39% of parents in the Sib-TD group, and the item relating to using another’s hand as a toolby 40% of parents in the low-risk group.  The mean number of these red flags in the Sib-ASD subgroup was 3.0 (SD = 2.1), significantly greater than in each of the other groups, which did not differ from each other.


Q-CHAT total scores at 24 months are potentially predictive of ASD status a year later. Furthermore, some specific items, relating primarily to a range of repetitive and stereotyped behaviours, may be sufficiently sensitive to act as red flags for ASD. Further validation in other whole population samples is ongoing.

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