The discrepancy between maturation of visual-evoked potentials and cognitive outcome at five years in very preterm infants with and without hemodynamic signs of fetal brain-sparing

Objective. After intrauterine growth restriction we found at the age of 6 m onths an acceleration of neurophysiologic maturation. However, at later age s impaired cognitive outcome has been reported. Therefore, we investigated in children with and without fetal hemodynamic adaptation to intrauterine g rowth restriction whether the accelerated neurophysiologic maturation in in fancy might be associated with impaired cognitive outcome at preschool age. Design. At 5 years of age cognitive function was assessed using the Revisio n of the Amsterdam Children's Intelligence Test in 73 preterm infants (26-3 3 weeks) who were prospectively followed from the antenatal period up to th e age of 5 years. Maternal educational level was used as a background varia ble to estimate the confounding effects of socioeconomic status on cognitiv e function. Fetal Doppler studies were performed and the umbilical artery p ulsatility index (PI) divided by the middle cerebral artery PI ratio (U/C r atio) was calculated. A U/C ratio >0.725 was considered as an indication of fetal cerebral hemodynamic adaptation to a compromised placental perfusion , ie, fetal brain-sparing. Visual-evoked potentials (VEPs) were recorded at 6 months and 1 year of age. In addition, data on neurologic status at 3 ye ars were available. Results. Mean IQ score was significantly lower for children born with a rai sed U/C ratio (87 +/- 16) compared with children with a normal U/C ratio (9 6 +/- 17). VEP latencies decreased significantly in infants with a normal U /C ratio, whereas no decrease was found in infants with a raised U/C ratio. Variables contributing significantly to the variance of cognitive function were: U/C group, VEP latency maturation, level of maternal education, and neurodevelopmental outcome at 3 years. The linear regression model explaine d 33% of the variance in cognitive function. Conclusions. Both being born with a raised U/C ratio and an acceleration of VEP latencies are negatively associated with cognitive outcome at 5 years of age. Fetal brain-sparing, although a seemingly beneficial adaptive mecha nism for intact neurologic survival, is, however, later associated with a p oorer cognitive outcome.