Delayed neonatal visual evoked potentials are associated to asymmetric growth pattern in twins

Abstract

Objectives: To study the association between intrauterine growth and visual pathways maturation by neonatal visual evoked potentials (VEPs) in twins, in view of a possible prognostic role. Methods: Seventy-four twin neonates from 37 pregnancies were selected based on gestational age of more than 30 weeks and uneventful perinatal clinical course. Flash VEPs were recorded at the same postmenstrual age in each twin pair. The association between P2 latency and anthropometric variables at birth was analyzed by comparison within each twin pair and regarding each variable as ordered difference between the two twins. Results: Analysis of differences within each twin pair highlighted that inter-twin difference in P2 latency was significantly related to difference in ponderal index (PI) (p = 0.048). Expressing the difference in latency as a categorical binary variable, the correlation was significant for both difference in PI, (median difference = −0.36, 95% CI −0.54 to −0.14, p = 0.001) and difference in body mass index (BMI), (median difference = −1.06, 95% CI −1.74 to −0.29, p = 0.006). Conclusions: Lower values of PI and BMI differences are associated to delayed VEP latency in twin pairs. Significance: VEP latency suggests reduced myelination of visual pathways when difference in growth pattern occurs in twins.