Neurodevelopmental outcome in preterm infants

AIM To determine the distribution of cognitive and motor scores in preterm children, and to establish the influence of brain lesions and decreasing gestational age thereon.METHOD One hundred and six very preterm children (63 males, 43 females; gestational age 24.0-31.6wk; birthweight 480-2275g) were assessed for cognition and motor outcome at 6 to 12 years. We assessed total, verbal, and performance IQ using the Wechsler Intelligence Scale for Children, and motor outcome using the Movement Assessment Battery for Children (Movement ABC).RESULTS The IQs and Movement ABC z-scores were normally distributed, but shifted to the left. Mean total IQ (SD) was 91 (12), performance IQ 89 (13), and verbal IQ 93 (15), being 0.60, 0.73, and 0.47 SD lower than the norm respectively. Movement ABC z-scores were -1.27 SD lower (SD 1.01). IQ and Movement ABC z-scores did not correlate with brain lesions or gestational age.INTERPRETATION The distribution curve for cognition and motor outcome at school age is shifted to the left in preterm children, with an effect size of 0.60 SD for IQ (nine IQ points) and 1.27 SD for motor outcome. These findings are restricted to the current group. Developmental disruptions, affecting cerebral white matter, cortex, cerebellum, and thalamus might be involved, although the exact pathogenetic mechanism is unclear.