Use of the Ages and Stages Questionnaire to predict outcome after hypoxic-ischaemic encephalopathy in the neonate

Background: Infants who suffer hypoxic-ischaemic encephalopathy (HIE) at birth are at increased risk of developmental disability. In this at-risk population, reliable, inexpensive and early identification of those children who are likely to require formal developmental assessment and intervention is needed. Aim: To evaluate the ability of the Ages and Stages Questionnaire (ASQ) to detect developmentally delayed children in an Australian population of infants who suffered HIE at birth. Methods: Fifty-five children who survived HIE were followed until 12-14 months of age. Test characteristics were calculated to examine the ability of the ASQ to appropriately identify developmentally delayed infants against this study's 'gold standard': the Bayley Scales of Infant Development II. Results: Comparing the ASQ with the Bayley Scales of Infant Development II, the questionnaire had the following test characteristics: sensitivity 92%, specificity 95%, positive predictive value 92%, negative predictive value 95% when used to detect severe developmental delay; and sensitivity 67%, specificity 93%, positive predictive value 92%, negative predictive value 68% when used to detect both severe and mild developmental delay. However, the ASQ used at standard cut-offs failed to detect any of the children with mild delay. Conclusions: The ASQ is extremely effective for the detection of severe developmental delay in children who have suffered HIE at birth. Its capacity to identify those with milder delay is limited. The ability of the test to detect only those with severe developmental delay means that the ASQ is of little value as a screening tool in this population.