Diagnostic accuracy of Ages and Stages Questionnaire, Third Edition to identify abnormal or delayed gross motor development in high‐risk infants

AimTo investigate the diagnostic accuracy of parent‐completed Ages and Stages Questionnaire, Third Edition (ASQ‐3) to identify abnormal or delayed gross motor development in infants born less than 1000 g or less than 28 weeks gestation.MethodsProspective cohort study of high‐risk infants comparing ASQ‐3 as the index test with concurrent score on Alberta Infant Motor Scale (AIMS) as the reference standard, at 4‐, 8‐ and 12‐month corrected (post‐term) age. Reference standard positivity cut‐offs were ‘Abnormal motor development’ (AIMS Clinical Range) and ‘Motor delay’ (AIMS score >1 SD below mean, not captured in Clinical Range).ResultsParticipating infants (n = 191) had mean gestational age (95% confidence interval (CI)) 26.8 weeks (26.6–27.1) and mean birthweight (95% CI) 870 g (844–896). AIMS rated 51%, 31% and 23% of infants as having ‘Abnormal motor development’ and 12%, 28% and 13% with ‘Motor delay’, at 4, 8 and 12 months, respectively. Diagnostic accuracy of ASQ‐3 to identify abnormal motor development was acceptable for older infants only if ‘Monitor’ cut‐off was used: sensitivity (95% CI) 33% (23–44), 86% (73–95) and 80% (63–92) and specificity (95% CI) 84% (74–92), 76% (66–84), and 76% (67–83) at 4, 8 and 12 months, respectively. ASQ‐3 sensitivity to identify motor delay was low.ConclusionsASQ‐3 has poor sensitivity to identify abnormal or delayed motor development at 4 months. Using the ‘Monitor’ cut‐off improves the diagnostic accuracy of ASQ‐3 for identification of older infants with abnormal motor development who are at high risk of motor disability. However, ASQ‐3 has poor sensitivity to identify motor delay. Clinical motor assessment of high‐risk infants is recommended, particularly in early infancy.