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Updated: May 25, 2026
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
Phase synchrony in the early preterm EEG: development of methods for estimating synchrony in both oscillations and
Anton Tokariev1, Kirsi Palmu, Aulikki Lano
1Department of Biosciences, University of Helsinki, Finland.
Insights
This study introduces objective measures for quantifying neuronal synchrony in preterm infant EEG, revealing how brain lesions impact developing neural networks. These findings offer new insights into early brain development and potential disorganization in vulnerable infants.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Developmental Pediatrics
Background:
- Neuronal connection development is crucial in preterm infants and relies on proper neuronal activity.
- Neonatal EEG assessment traditionally uses visual synchrony analysis, lacking objective measures and clear definitions.
- Existing phase locking value (PLV) methods for adults are not directly applicable to unique neonatal EEG characteristics.
Purpose of the Study:
- To develop and validate objective measures for quantifying neuronal synchrony in neonatal EEG signals.
- To adapt existing PLV methods for neonatal EEG at different temporal scales (oscillations and events).
- To investigate the impact of cerebrovascular lesions on brain network development in very preterm infants.
Main Methods:
- Adapted and extended Phase Locking Value (PLV) methods for neonatal EEG signals.
- Quantified phase synchrony (PS) between band-specific amplitude envelopes (bafPS) at two temporal scales.
- Developed a measure based on cumulative proportion of time with statistically significant synchrony.
- Applied the method to dense array EEG recordings from preterm infants (<30 weeks conceptual age).
Main Results:
- Successfully adapted PLV-based methods for neonatal EEG analysis at both oscillatory and event-based temporal scales.
- Demonstrated that cerebrovascular lesions in preterm infants can have selective spatial and frequency-dependent effects on brain synchrony.
- Identified that these effects are often undetectable through conventional visual EEG interpretation.
Conclusions:
- The developed objective measures provide a novel way to assess neuronal synchrony in preterm infants.
- Brain lesions significantly impact the development and organization of somatosensory networks in early preterm babies.
- These findings have implications for understanding and potentially intervening in the neurodevelopmental trajectories of high-risk infants.
Abstract:
Development of neuronal connections relies on proper neuronal activity, and it starts during the time when early preterm babies are treated in the neonatal intensive care units. While synchrony has been a key element in visual assessment of neonatal EEG signals, there has been no unambiguous definitions for synchrony, and no objective measures available for neonatal signals. Estimation of phase locking value (PLV) has been an established paradigm in adults, but many unique characteristics of the neonatal EEG have precluded its applicability in them. In the present paper, we developed the existing PLV-based methods further to be applicable for neonatal signals at two different temporal scales, oscillations and events, where the latter refers technically to quantitating phase synchrony (PS) between band-specific amplitude envelopes (bafPS). In addition, we present a measure for quantitation based on assessing cumulative proportion of time with statistically significant synchrony between the given signal pair. The paper uses real EEG examples and the prior neurobiological knowledge in the process of defining optimal parameters in each step of the procedure. Finally, we apply the method to a set of dense array EEG recordings from very early preterm babies, recorded at conceptional age of less than 30 weeks. By comparing PS and bafPS from babies without and with major cerebrovascular lesion, we show that the effects of brain lesions may be selective both in space and in frequency. These findings do by nature escape visual detection in the conventional EEG reading, however they have intriguing correlates in the current concept of how somatosensory networks are thought to develop and/or become disorganized in the early preterm babies.
