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
S. Scherjon et al., 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, PEDIATRICS, 105(2), 2000, pp. 385-391
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.