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.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype