Functional connectivity in preterm infants derived from EEG coherence analysis

Objective : To quantify the neuronal connectivity in preterm infants between homologous channels of both hemispheres. Methods : EEG coherence analysis was performed on serial EEG recordings collected from preterm infants with normal neurological follow-up. The coherence spectrum was divided in frequency bands: dnewborn(0–2 Hz), ¿newborn(2–6 Hz), anewborn(6–13 Hz), ßnewborn(13–30 Hz). Coherence values were evaluated as a function of gestational age (GA) and postnatal maturation. Results : All spectra show two clear peaks in the dnewborn and ¿newborn-band, corresponding to the delta and theta EEG waves observed in preterm infants. In the dnewborn-band the peak magnitude coherence decreases with GA and postnatal maturation for all channels. In the ¿newborn-band, the peak magnitude coherence decreases with GA for all channels, but increases with postnatal maturation for the frontal polar channels. In the ßnewborn-band a modest magnitude coherence peak was observed in the occipital channels, which decreases with GA. Conclusions : Interhemispherical connectivity develops analogously with electrocortical maturation: signal intensities at low frequencies decrease with GA and postnatal maturation, but increase at high frequencies with postnatal maturation. In addition, peak magnitude coherence is a clear trend indicator for brain maturation. Significance : Coherence analysis can aid in the clinical assessment of the functional connectivity of the infant brain with maturation.