A short questionnaire could be used to detect autism in toddlers, new research has suggested.
Researchers from the University of Cambridge have determined that autism can be found in children aged 18 to 30 months old using the Quantitative Checklist for Autism in Toddlers (Q-CHAT), but it is not possible to identify every child at a young age who will later be diagnosed as autistic.
The findings have been published in The BMJ Paediatrics Open.
Checklist for autism in toddlers
The Q-CHAT is a parent-report instrument developed by the team at the Autism Research Centre in Cambridge. Researchers used this to screen almost 4,000 toddlers at 18 months and then in a follow-up screening at four years old.
The Q-CHAT is an updated version of the CHAT, originally published by the same authors in the 1990s. The key components of the test are the same, but it also includes items that examine language development, repetitive and sensory behaviours, and other aspects of social communication behaviours. The checklist has 25 items, all of which contain a range of response options that allow for a reduced rate of key behaviours.
In phase one of the new research, 13,070 caregivers were invited to complete the Q-CHAT about their children aged 18-30 months old. 3,770 caregivers returned the Q-CHAT, and 121 of these were invited for an autism diagnostic assessment.
Phase two of the assessment followed up the children at the age of four using the Childhood Autism Screening Test (CAST), and a checklist to determine whether any of the children had been referred or diagnosed with any developmental conditions, including autism. Autism assessments were made using intecomrnationally recognised methods.
The sensitivity (the proportion of autistic children correctly identified by the Q-CHAT as being autistic) of the Q-CHAT in predicting autism at phase two is 44%, and the specificity (the proportion of children who are not autistic and who are correctly identified by the Q-CHAT as not being autistic) is 98%. Results also showed that the ‘positive predictive value’ (the proportion who screened positive on the Q-CHAT who were found to be autistic) is 28%.
Detecting and diagnosing autism in young children
As all 11 children who were classified as autistic scored at or above the cut-point of 39, the findings of the study suggest that the Q-CHAT can be used to detect and diagnose autism at an early age. However, the Q-CHAT did not identify all children during toddlerhood who were later diagnosed with autism at age four, most likely reflecting that some autistic children do not show significant symptoms until later in childhood.
Dr Carrie Allison, Director of Research Strategy at the Autism Research Centre, who led the study, said: “This study tells us that autism can be detected during the toddler years, and that other children may only be identified as autistic later. Repeat screening and surveillance across development may be a better approach rather than relying on a single time point.”
Tony Charman, Professor of Clinical Child Psychology at Kings College London, and a member of the team, said: “Screening for autism in infancy means that children can be fast-tracked into early intervention, which we know can lead to better outcomes for many children. This is an exciting advance because most other autism screening measures in toddlers have not been subject to rigorous population studies of this kind.”
Professor Sir Simon Baron-Cohen, Director of the Autism Research Centre and a member of the team, said: “25 years ago, our team was the first to show autism could be screened and diagnosed as young as 18 months of age. This new study shows how our original screening instrument – the CHAT – has been revised into a better instrument – the Q-CHAT, which can pick up children who need an autism diagnosis. Early detection means happier, healthier, children, and families because they can be targeted with support.”