Determinants of visual evoked potentials in preterm infants.

The latency and amplitude of N1, the first negative peak of single flash visual evoked cortical potentials (VEP) were evaluated in 86 preterm infants (25-34 weeks of gestation), investigated during the first day of life. All infants were regarded stable at the time of investigation and none had experienced severe asphyxia. Both the VEP latency and amplitude were inversely related to gestational age. When latency was corrected for age it was longer in boys than in girls. Age corrected VEP amplitude was inversely related to head circumference, umbilical cord pH and EEG activity. There was no difference between VEP parameters in asymmetrically growth retardated infants compared to those with normal growth. Administration of dexamethasone to the mother before delivery, mode of delivery, presence of hyaline membrane disease, mode of assisted ventilation or imminent development of periintraventricular haemorrhage did not affect the VEP.