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• Negative central activity (NCA) is a frequent triphasic abnormal electroencephalographic feature of the extreme prematurity. • NCA is associated with severe intraventricular haemorrhage and may reflect the functional neural impact of vascular pathology. • The NCA association with adverse outcome argues for its consideration in brain function assessment and prognosis prediction. To characterize Negative Central Activity (NCA), an overlooked electroencephalographic activity of preterm newborns and investigate its relationship with brain injuries, dysfunction, and neurodevelopmental outcome. 109 preterm infants (23–28 weeks) were retrospectively included. NCA were selected at the negative peak on EEG. Individual averaged NCA were automatically characterized. Brain structural data were collected from cranial ultrasounds (cUS). The neurodevelopmental outcome at two years of age was assessed by the Denver Developmental Screening Test-II. Thirty-six (33%) children showed NCA: 6,721 NCA were selected, a median of 75 (interquartile range, 25/157.3) per EEG. NCA showed a triphasic morphology, with a mean amplitude and duration of the negative component of 24.6–40.0 µV and 222.7–257.3 ms. The presence of NCA on EEG was associated with higher intraventricular haemorrhage (IVH) grade on the first (P = 0.016) and worst neonatal cUS (P < 0.001) and poorer neurodevelopmental outcome (P < 0.001). NCA is an abnormal EEG feature of extremely preterm newborns that may correspond to the functional neural impact of a vascular pathology. The NCA relationships with an adverse outcome and the presence/severity of IVH argue for considering NCA in the assessment of pathological processes in the developing brain network and for early outcome prediction. [ABSTRACT FROM AUTHOR]

Electroencephalography is the only clinically available technique that can address the premature neonate normal and pathological functional development week after week. The changes in the electroencephalogram (EEG) result from gradual structural and functional modifications that arise during the last trimester of pregnancy. Here, we review the structural changes over time that underlie the establishment of functional immature neural networks, the impact of certain anatomical specificities (fontanelles, connectivity, etc.) on the EEG, limitations in EEG interpretation, and the utility of high-resolution EEG (HR-EEG) in premature newborns (a promising technique with a high degree of spatiotemporal resolution). In particular, we classify EEG features according to whether they are manifestations of endogenous generators (i.e. theta activities that coalesce with a slow wave or delta brushes) or come from a broader network. Furthermore, we review publications on EEG in premature animals because the data provide a better understanding of what is happening in premature newborns. We then discuss the results and limitations of functional connectivity analyses in premature newborns. Lastly, we report on the magnetoelectroencephalographic studies of brain activity in the fetus. A better understanding of complex interactions at various structural and functional levels during normal neurodevelopment (as assessed using electroencephalography as a benchmark method) might lead to better clinical care and monitoring for premature neonates. [ABSTRACT FROM AUTHOR]