EXTREME PREMATURITY IN HEALTHY 5-YEAR-OLD CHILDREN - A REANALYSIS OF SEX EFFECTS ON EVENT-RELATED BRAIN ACTIVITY

A male disadvantage has been reported in several outcome studies of ch ildren born preterm. Twenty-two healthy premature children (10 girls, 12 boys) born between 25 and 28 weeks of gestation and 20 controls bor n full-term (10 boys, 10 girls) were matched on socioeconomical status and age. Event-related potentials (ERPs) were recorded by using 14 el ectrodes in a visual oddball task, with 75% frequent and 25% rare stim uli. This task elicited a larger P3 to the rare than to the frequent s timuli, with a prominent parietocentral localization. However, the amp litude was larger in full-term boys than in full-term girls, a differe nce that was not observed between preterm boys and preterm girls, espe cially to targets and on the central electrodes. In addition, the pret erm group was characterized by a frontal slow wave larger in boys than in girls. In these prematures, the lack of the sex-related difference may be accounted by differences in the strength of the neuronal gener ators in males, as they might have been affected by the high level of androgens by the fetal testis under the control of placental gonadotro pes during the first two thirds of gestation.