Search

• 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]

Temporal theta slow‐wave activity (TTA‐SW) in premature infants is a specific neurobiomarker of the early neurodevelopment of perisylvian networks observed as early as 24 weeks of gestational age (wGA). It is present at the turning point between non‐sensory driven spontaneous networks and cortical network functioning. Despite its clinical importance, the underlying mechanisms responsible for this spontaneous nested activity and its functional role have not yet been determined. The coupling between neural oscillations at different timescales is a key feature of ongoing neural activity, the characteristics of which are determined by the network structure and dynamics. The underlying mechanisms of cross‐frequency coupling (CFC) are associated with several putative functions in adults. In order to show that this generic mechanism is already in place early in the course of development, we analyzed electroencephalography recordings from sleeping preterm newborns (24–27 wGA). Employing cross‐frequency phase–amplitude coupling analyses, we found that TTAs were orchestrated by the SWs defined by a precise temporal relationship. Notably, TTAs were synchronized to the SW trough, and were suppressed during the SW peak. Spontaneous endogenous TTA‐SWs constitute one of the very early signatures of the developing temporal neural networks with key functions, such as language and communication. The presence of a fine‐tuned relationship between the slow activity and the TTA in premature neonates emphasizes the complexity and relative maturity of the intimate mechanisms that shape the CFC, the disruption of which can have severe neurodevelopmental consequences. [ABSTRACT FROM AUTHOR]