Abstract
BACKGROUND: Early detection of cognitive disability is challenging. We assessed the domain-specific, concurrent validity of the ages and stages questionnaire (ASQ-3) and the Bayley Scales of Infant and Toddler Development (BSID-III), and their ability to predict cognitive delay at school age. METHODS: Within a longitudinal birth cohort study, a nested cohort of children was assessed using ASQ-3 and BSID-III at 24 months, and at 5 years using the Kaufmann brief IQ test (KBIT). RESULTS: 278 children were assessed using BSID-III and ASQ-3 at 24-months; mean(SD) BW = 3445(506) grams, M:F ratio=52:48. ASQ-3 had reasonable predictive ability (AUROC, p value, sensitivity:specificity) of same domain delay for motor (0.630, p = 0.008, 50%:76.1%) and language (0.623, p = 0.010, 25%:99.5%) at 2 years, but poor ability to detect cognitive delay compared to BSID-III (0.587, p = 0.124, 20.7%/96.8%;). 204/278 children were assessed at 5 years. BSID-III language and cognition domains showed better correlation with verbal and nonverbal IQ (R = 0.435, p < 0.001 and 0.388, p < 0.001 respectively). Both assessments showed high specificity and low sensitivity for predicting delay at 5 years. CONCLUSIONS: The ASQ-3 cognitive domain showed poor concurrent validity with BSID-III cognitive score. Both ASQ-3 and BSID-III at 2 years poorly predict cognitive delay at 5 years. IMPACT: The ASQ-3 does not adequately detect cognitive delay or predict cognitive delay at 5 years, particularly for children with mild to moderate delay. The ASQ-3 shows reasonable concurrent validity with the motor and language subscales of the BSID-III. Neither early screening nor formal developmental testing demonstrated significant predictive validity to screen for cognitive delay at school age. This article highlights the need to analyse our existing model of using the ASQ-3 to screen for cognitive delay in children aged 2 years.