Differences in the maturation of amplitude-integrated EEG signals in male and female preterm infants.

Background: The amplitude-integrated electroencephalogram (aEEG) is a valuable tool for monitoring brain function in preterm infants. Several studies have discussed sex-related differences regarding neonatal morbidity and mortality. To date, no study has been published specifically evaluating potential sex-related differences in aEEG parameters.

Objective: The aim of this study was to assess sex-related differences in aEEG signals in preterm born infants without brain injury in the first 4 weeks of life.

Methods: aEEG was performed at seven time points (days 1, 2, 3, weeks 1, 2, 3 and 4) and analyzed for Burdjalov total score, number of bursts per hour and visual background pattern.

Patients: One hundred and fifty-six infants (85 male and 71 female) born with a gestational age between 28 and 31 completed weeks were evaluated.

Results: Mean total score increased with postnatal age and ranged from 5.4 at day 1 to 11.0 at the end of the study period. The score was higher for girls at every time point, and the mean difference was between 0.3 and 0.9. The number of bursts per hour decreased over time from 8.9 at day 1 to 1.6 at the end of the study period. At week 4, the number of bursts per hour was significantly lower in girls (1.3) than in boys (2.0).

Conclusion: Sex-related differences were present in aEEG signals of preterm infants. The lower total score and the higher number of bursts might express delayed brain maturation in male preterm infants.