Presented at the Neonatal Society 2012 Spring Meeting.
Wong HS1, Huertas-Ceballos A2, Cowan FM1, Modi N1 on behalf of the Medicines for Neonates Investigator Group
1 Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster campus, Imperial College London, UK
2 Neonatal Intensive Care Unit, University College London Hospital, UK
Background: The Quantitative Checklist for Autism in Toddlers (Q-CHAT) is a newly developed parent-completed questionnaire that provides a quantitative measure of early childhood social-communication difficulty (1). The Q-CHAT contains 25 items, representing different aspects of social-communication, scored on a 5-point scale (0-4) with a higher score representing greater difficulty. Infants born preterm are at greater risk of autism spectrum disorder (ASD) (2). We aimed to compare Q-CHAT scores in children without severe impairment born <30 weeks gestation with previously published general population scores. As communication abnormalities are key features of ASD, we also aimed to explore if any observed difference in Q-CHAT scores was explained by delayed language development in the preterm population.
Methods: We recruited children born <30 weeks gestation and between 20-28 months corrected age to participate in a larger study evaluating the reliability of routinely collected neurodevelopmental data. All participants received a Bayley-III developmental assessment. Parents were invited to complete the Q-CHAT. Children with severe visual or hearing impairment, cerebral palsy and/or Bayley-III cognitive composite score<70 were ineligible for this analysis. Q-CHAT scores were compared with general population norms (mean 26.7, SD 7.8) using Student’s t-test. The differences in the distributions of item-specific scores between the study cohort and published distributions of the general population were examined by Chi-square tests. Linear regression analysis was conducted to determine the correlation between Q-CHAT scores and Bayley-III language composite scores. The conventional 5% level was used to define statistical significance.
Results: The Q-CHAT was completed by the parents of 111 children (mean [SD] gestation 26.9 [1.7] weeks; mean corrected age at assessment 24.7 [2.8] months). Q-CHAT scores in the study cohort were normally distributed (mean 34.0 [7.6]) and significantly higher than the general population scores (p<0.001). There were statistically significant differences in the distributions of item-specific scores in 16/25 (64%) items between the study cohort and the general population. These 16 items represented non-verbal aspects of behaviour (eg ability to initiate eye contact; adaptation to changes in routines) as well as language development (eg typicality of first words). Although Bayley-III language composite scores predicted QCHAT scores in a linear fashion (regression coefficient: -0.30 [95% CI -0.40 to -0.20]; p<0.01), this accounted for only 24.2% of the variance in Q-CHAT scores (correlation coefficient: -0.49; R2: 0.24).
Conclusion: The Q-CHAT identified greater social-communication difficulties in children born <30 weeks gestation than in the general population. Difficulties were present in verbal and non-verbal aspects of socialcommunication. Language development accounted for a quarter of the variance in Q-CHAT scores. The QCHAT may be a valuable tool for the early identification of preterm infants at risk of ASD. It will now be important to establish precise predictive validity.
Corresponding author: firstname.lastname@example.org
1. Allison C, et al. The Q-CHAT: a normally distributed quantitative measure of autistic traits at 18-24 months of age: a preliminary report. J Autism Dev Disord 2008;38:1414-25.
2. Johnson S, et al. Autism spectrum disorders in extremely preterm children. J Pediatr 2010;156:525-31.