Summary
Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on “Biosignal Interpretation: Advanced Methods for Neural Signals and Images“.
Objectives: 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] × [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.
Keywords
EEG - full-term newborn - premature newborn - time-variant - quadratic phase coupling