Shepherd A, McCulloch DL, Saunders KJ, Bradnam MS, Wilkinson AG & Turner TL (1997) Early maturation of the flash visual evoked potential in preterm infants: Influence of flash intensity and sleep state. Prenatal and Neonatal Medicine, 2 (3), pp. 249-257.
Objective: To investigate the development of the flash visual evoked potential (VEP) and to examine the influence of flash intensity, sleep state and gestational age on the resulting VEP waveform.
Subjects and methods: Flash VEPs using two different intensities of stroboscopic light were recorded and sleep state was noted in 34 premature infants born between 28 and 35 weeks' gestation.
Results: A long latency negative component (N3) was evident in all preterm infants tested at 3 days of age. The latency and amplitude of N3 were unrelated to gestational age, flash intensity or sleep state. A positive component (P2) was evident in 38% of these infants. The flash VEP of preterm infants matured greatly between day 3 and term age. At term age, the P2 component was prominent in all infants. Its latency decreased as wakefulness increased and its amplitude increased with an increase in flash intensity.
Conclusion: There is vast neuroanatomical development in the visual cortex in preterm infants from birth to term age demonstrated by the maturing VEP. The study also highlights the effect of flash intensity and sleep state on the VEP waveform and the need for these variables to be carefully monitored.
Flash intensity; Preterm neonates; Sleep state; Visual evoked potential
Prenatal and Neonatal Medicine: Volume 2, Issue 3