High‐density electroencephalography developmental neurophysiological trajectories

Abstract

HIE Hypoxic-ischaemic encephalopathyEfforts to document early changes in the developing brain have resulted in the construction of increasingly accurate structural images based on magnetic resonance imaging (MRI) in newborn infants. Tractography diagrams obtained through diffusion tensor imaging have focused on white matter microstructure, with particular emphasis on neuronal connectivity at the level of fibre tract systems. Electroencephalography (EEG) provides a complementary approach with more direct access to brain electrical activity. Its temporal resolution is excellent, and its spatial resolution can be enhanced to physiologically relevant levels, through the combination of high-density recordings (e.g. by using 64 channels in newborn infants) and mathematical models (e.g. inverse modelling computation), to identify generators of different oscillation bands and synchrony patterns. The integration of functional and structural topography of the neonatal brain provides insights into typical brain organization, and the deviations seen in particular contexts, for example the effect of hypoxic-ischaemic insult in terms of damage, eventual reorganization, and functional changes. Endophenotypes can then be used for pathophysiolgical reasoning, management planning, and outcome measurements, and allow a longitudinal approach to individual developmental trajectories.Over the last few years, there have been dramatic advances in the documentation of early structural changes in the developing brain, and improved understanding of the processes underlying these changes. On the macroscopic scale, many of these advances have concerned magnetic resonance imaging (MRI). Major research efforts have resulted in finely documenting the prenatal and early postnatal maturation of the cerebral cortex in terms of the evolution of cortical thickness and volume. Examples include the demonstration of several so-called 'transient fetal zones', which disappear before late infancy, such as the cortical plate. 1 In addition, three-dimensional reconstruction techniques provide qualitative as well as quantitative mapping of cortical folding, allowing the timescale of the appearance of gyri and sulci to be followed. These techniques can also be used to demonstrate some specific early asymmetries, such as the earlier emergence of gyral complexity in the right cerebral hemisphere than in the left. An alternative magnetic resonance neuroimaging approach, increasingly being used in research and clinical practice, is diffusion tensor imaging, which quantifies the random motion of water molecules. Restrictions to this motion are measured by fractional anisotropy and mean diffusivity. These measures indicate directional constraints and reflect the direction of fibre tracts. This interpretation is reinforced by the increasing recognition of the role of axonal membranes in diffusion anisotropy. Therefore, diffusion tensor imaging has provided important insights into the microstructure and organization of cerebral white matter.2 This approach has led t...

High‐density neonatal electroencephalography provides biomarkers for developmental trajectories

“…Jozef Lebeer https://orcid.org/0000-0001-5929-7783 Electroencephalography (EEG) has long been used to diagnose and monitor neurological disorders, but it can also provide a unique window into the functioning of the developing brain. 1 EEG can be recorded from the preterm period in newborn infants to document developmental patterns that reflect the progressive organization of brain networks. It can thus provide valuable biomarkers for early developmental trajectories.…”

“…by using 64 or 128 channels). 1,2 If using appropriate mathematical tools, this has the potential to identify brain activities that were previously unknown or difficult to localize, and effectively characterize developmental neurophysiological trajectories in follow-up studies. Measures performed on high-density EEG signals might therefore be the next step when studying functional neuroplasticity induced by early intervention.…”

“…To enhance the spatial accuracy of EEG to physiologically relevant levels in particular in young infants, high‐density recordings are required (e.g. by using 64 or 128 channels) 1,2 . If using appropriate mathematical tools, this has the potential to identify brain activities that were previously unknown or difficult to localize, and effectively characterize developmental neurophysiological trajectories in follow‐up studies.…”

Multiscale entropy as a metric of brain maturation in a large cohort of typically developing children born preterm using longitudinal high-density EEG in the first two years of life

“…It has excellent temporal resolution, and its spatial accuracy can be enhanced to physiologically relevant levels through high-density recordings, e.g. by using 64 channels in newborn infants, making it possible to enhance brain activities that were previously unknown or difficult to localize and characterize developmental neurophysiologic trajectories (Dan et al 2015).…”