The effect of maturation and sedation on amplitude-integrated electroencephalogram of the preterm neonate:: Results of a prospective study

Background and aim: Amplitude-integrated electroencephalogram (aEEG) is becoming more common in NICUs for monitoring infants after perinatal asphyxia. We used aEEGs for preterm infants, and analysed the influence of sedation and maturation on their aEEG, focusing on continuous activity. Methods: Weekly or biweekly aEEGs were performed in preterm infants and evaluated by visual analysis. Results: We analysed 92 aEEGs of 56 preterm infants (gestational age (GA) 24 + 6 to 34 + 0 wk, median 30 + 0 wk). In their first week of life, children with higher GA had a higher percentage of continuous activity: with a GA <= 28 + 0 wk it was 8.1%, 33.5% with a GA from 28 + 1 to 30 + 0 wk (p = 0.02), 85.9% with a GA from 30 + 1 to 32 + 0 wk (p = 0.005), and 89.1% with a GA from 32 + 1 to 34 + 0 wk. Continuous activity increased with growing postnatal age. With a GA <= 28 + 0 wk, it rose from 8.1% (first week) to 55.3% (second week) and reached 96.8% (week 6/7) (p = 0.017). With GA from 28 + 1 to 30 + 0 wk, continuous activity was 33.5% (first week) and 86.6% (second week) (p = 0.03). Conclusion: The aEEG of preterm infants appears to be a good tool for monitoring cerebral activity. Continuous activity seems to indicate maturation in the neonatal brain. Further investigations of aEEGs in preterm infants should be performed.