The amplitude-integrated electroencephalogram (aEEG) is a simple and convenient tool for brain function monitoring. It is being more widely used in monitoring high risk neonates in neonatal intensive care units. Normal values and patterns for aEEG activity in preterm infants are still being developing. Here we report the functional brain maturation of preterm twin siblings with aEEG who were severely affected by fetal growth discordance. The aEEG records of growth retarded twin was compared with her appropriate for gestational age sibling in order to see if there is also a developmental discordance in the functional brain maturation of these twins. (c) 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.