Quadratic Phase Couplings in the EEG of Premature and Full-term Newborn during Quiet Sleep.
BACKGROUND
This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Neural Signals and Images".


OBJECTIVE
The aim of this study was to compare rhythmicities in the quadratic phase coupling (QPC) in the tracé discontinue EEG patterns (TD) of premature newborns and the tracé alternant EEG patterns (TA) of full-term newborns by means of time-variant bispectral analysis. Both pattern occur during quiet sleep and are characterized by an ongoing sequence of interburst and burst patterns. The courses of time-variant bispectral measures during the EEG burst most likely indicate specific interrelations between cortical and thalamocortical brain structures.


METHODS
The EEG of a group of premature (n = 5) and of full-term (n = 5) newborns was analysed. Time-variant QPC was investigated by means of time-variant parametric bispectral analysis. The frequency plain [0.5 Hz, 1.5 Hz] x [3 Hz, 6 Hz] was used as the region-of-interest (ROI).


RESULTS
QPC rhythms with a frequency of 0.1 Hz (8 - 11 s) were found in all full-term newborns at all electrodes. For the premature newborns the QPC rhythms were less stable and slower (< 0.1 Hz, 11 -  17 s) at all electrodes and showed a higher inter-individual variation than for the full-term newborns. Statistically, the adaptation of a linear mixed model revealed a difference of about 5 s between both groups of newborns.


CONCLUSIONS
The comparison of the results of both groups of newborns indicates a development in the interaction between cortical, thalamocortical and neurovegetative structures in the neonatal brain.
Karin Schiecke, Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Friedrich Schiller University Jena, Bachstr. 18, 07740 Jena, Germany, E-mail: Karin.Schiecke@med.uni-jena.de.
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Schiecke
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Eiselt
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Schlattmann
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Witte
D000465:Algorithms; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016014:Linear Models; D012890:Sleep
EEG; full-term newborn; premature newborn; quadratic phase coupling; time-variant