Minor neurodevelopmental impairments are associated with increased occurrence of ADHD symptoms in children born extremely preterm

ADHD is more common in children born preterm than at term. The purpose of the study was to examine if, and to what extent, ADHD symptoms are associated with minor neurodevelopmental impairments (NDI) in extremely preterm children. In a national population-based cohort with gestational age 22-27 weeks or birth weight < 1,000 g assessed at 5 years of age, scores on Yale Children's Inventory (YCI) scales (seven scales) were related to normal functions vs. NDI defined as mild impairments in cognitive function (IQ 70-84), motor function (Movement Assessment Battery for children score > the 95th percentile or freely ambulatory cerebral palsy), vision (correctable), and hearing (no hearing aid). YCI was completed for 213 of 258 eligible children (83 %). Children with minor NDIs (n = 98) had significantly higher scores (more ADHD symptoms) than those without NDI (n = 115) on the YCI scales of Attention, Tractability, Adaptability and Total score. Increasing numbers of minor NDIs were associated with higher mean YCI scores. In multivariate analysis only decreased hearing, IQ, and male gender were significantly associated with scores on the Attention scale. Thirty-three children (16 %) had scores > 3 on the Attention scale (probably ADHD), and the proportion was significantly higher for those with mild NDIs compared to those without (Odds ratio = 2.7, 95 % CI 1.3-6.0). Children born extremely preterm with minor NDIs were more likely to have ADHD symptoms than those with no NDI, and increasing number of minor NDIs were associated with more ADHD symptoms.