Phase synchrony in the early preterm EEG: Development of methods for estimating synchrony in both oscillations and events

Anton Tokariev, Kirsi Palmu, Aulikki Lano, Marjo Metsäranta, Sampsa Vanhatalo*

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    31 Citations (Scopus)

    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.

    Original languageEnglish
    Pages (from-to)1562-1573
    Number of pages12
    JournalNeuroImage
    Volume60
    Issue number2
    DOIs
    Publication statusPublished - 2 Apr 2012
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Connectivity
    • Neonatal neurophysiology
    • Newborn
    • Preterm EEG

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