Developmental coordination disorder in geographic cohorts of 8-year-old children born extremely preterm or extremely low birthweight in the 1990s

Aim: The aim of the study was to examine the prevalence of developmental coordination disorder (DCD) at the age of 8 years in a geographic cohort of extremely preterm or extremely-low-birthweight (EP/ELBW) children and a term-born comparison group, as well as associated academic outcomes, parents' perceptions of motor performance, and changes in prevalence during the 1990s. Method: Moderate DCD was defined as a score below the 5th centile on the Movement Assessment Battery for Children in children without cerebral palsy or intellectual impairment. DCD rates were compared in a group of 132 8-year-old children born in 1997 at 22 to 27 weeks' gestation or birthweight of less than 1000g (49% male, 51% female) and a comparison group of 154 term-born children (55% male, 45% female). The Wechsler Intelligence Scale for Children - 4th edition and the Wide Range Achievement Test - 3rd edition were used to measure academic and cognitive outcomes. Parental perceptions of motor performance were measured using the physical function scale of the Child Health Questionnaire, parent-report form (CHQ PF50). The results for children with and without DCD were then compared. To assess changes in prevalence throughout the 1990s, DCD rates were compared with those found in children from the same region born in 1991 to 92. Results: The mean number of completed weeks of gestation in the EP/ELBW children and in the comparison group of term-born children for whom data were available for analysis was 26.5 (SD 1.9) and 39.2 (SD 1.1) respectively, and the mean birthweight was 830g (SD 163) and 3511g (SD 462) respectively. The prevalence of DCD was 16% in the EP/ELBW group and 5% in the comparison group (odds ratio 3.45; 95% confidence interval [CI] 1.47-8.09%). Academic outcomes for reading, spelling, and arithmetic were poorer among children with DCD than among those without DCD (mean difference [95% CI] 10.2 [0.9-19.7; p=0.03], 8.9 [2.2-15.5; p=0.01], and 7.9 [1.4-14.5; p=0.02] respectively). Parental perceptions were poorly predictive of DCD. Interpretation: EP/ELBW children have higher rates of DCD and experience more academic difficulties than term-born children. As parental perceptions are not a reliable screen, clinical assessments of motor skills in this vulnerable population are important.