Trends in cyclicity and amplitudes on amplitude-integrated electroencephalography during transition in extremely low gestational age infants

Aim: The aim of the study was to describe amplitude integrated electroencephalography (aEEG) cyclicity, background pattern, voltage margins and maturation scores in extremely low gestational age neonates (ELGANs) in the first 72 h. Methods: Fifty infants with gestational age (GA) 23+0-27+6 weeks were prospectively studied. Infants with intraventricular haemorrhage <= Grade I and no disorders of transition (persistent pulmonary hypertension, hypotension, pulmonary haemorrhage) belonged to the 'Uncomplicated' group and those with intraventricular haemorrhage > Grade I and/or disorders of transition, to the 'Complicated' group. Results: Thirty-six infants without opioid exposure were included: 23 with GA 25.9 (23.1-27.7) weeks in the 'Uncomplicated' group and 13 with GA 24.6 (23.3-27.4) weeks in the 'Complicated' group. Cyclicity was more common in the 'Uncomplicated' group [20/23 (87%) vs. 7/13 (54%), p = 0.045] with more cycles/hour [0.2 (0-0.78) vs. 0.03 (0-67), p = 0.036]. Age at appearance of cyclicity was similar [20 (7.7-40.7) hours in 'Uncomplicated' vs. 23.7 (5.4-60) hours in 'Complicated' group, p = 0.8]. In the 'Uncomplicated' group, maturation scores (p = 0.02), high (p < 0.0001) and low (p = 0.03) base voltage increased over time. Conclusion: During the first 72 h, clinically stable ELGANs without neurological injury demonstrate increased cyclicity compared to those with a complicated course. Maturation score, high and low base voltage increase over time.