Background patterns and sleep-wake cycles on amplitude-integrated electroencephalography in preterms younger than 30 weeks gestational age with peri-/intraventricular haemorrhage

Aim: The objective of this prospective study was to evaluate the influence of peri-/intraventricular haemorrhage (PIVH) grades I-IV on amplitude-integrated electroencephalographic (aEEG) activity in preterm infants < 30 weeks gestational age (GA). Methods: The aEEG tracings of the first 2 weeks of life of 56 preterm infants younger than 30 weeks GA (2 groups: group A = 23-26 weeks GA, group B = 27-29 weeks GA) born during a 4-year period with PIVH grades I-IV were assessed for the relative duration of four background aEEG activity patterns (continuous pattern, discontinuous high-voltage pattern, discontinuous low-voltage pattern and nearly isoelectric pattern), the presence of seizure activity and the appearance of sleep-wake cycles and compared to the tracings of 75 neurologically healthy preterms without PIVH. Results: Analysis of aEEG background activity showed a decrease of continuous activity whereas discontinuous activity increased in both groups with larger haemorrhages (grades III and IV) and when compared to controls. Suspected seizure activity was more common with increasing degree of bleeding in group A (50% with PIVH I or II, 75% with PIVH III or IV) and when compared to controls and was the same with increasing degree of bleeding in group B (47% with PIVH I or II, 45% with PIVH III or IV). Sleep-wake cycles were less common with larger haemorrhages in both groups (group A: 41% with PIVH I or II, 25% with PIVH III or IV; group B: 52% with PIVH I or II, 9% with PIVH III or IV) and when compared to controls. Conclusions: The aEEG characteristics of severe PIVH consist in a combination of a more discontinuous background pattern, a lack of sleep-wake cycles and a higher likelihood of seizure activity when compared to age-matched controls.