Clinical significance of electroencephalography power spectrum density and functional connection analysis in neonates with hypoxic-ischemic encephalopathy

Objective To investigate the effects of electroencephalography (EEG) power and functional connectivity analysis on cerebral cortex function in neonates with hypoxic-ischemic encephalopathy (HIE), and to identify the neurobiological indicators of neural development in HIE. Methods We recruited 20 mild HIE neonates, 15 moderate HIE neonates, and 30 controls. EEG was performed about 72 hr after birth. The power spectral density (PSD) and imaginary part of coherency (ICOH) were analyzed. Gesell developmental schedule (GDS) was used to evaluate the neural development in the mild and moderate HIE groups at 1 year of age, and the correlation between the quantitative EEG results and the state of neural development was analyzed. Results Compared with the controls, FP1, FP2, C3, C4, Fz, Cz, Pz , F3, and P4 of moderate HIE neonates showed that the PSD of theta, alpha and beta bands decreased significantly. In terms of the mean whole-brain PSD, the moderate HIE group showed a significant decrease in all frequency bands. ICOH of the moderate HIE group showed that functional connectivity was significantly less than that in the controls mainly in the delta band, and the functional connectivity of the delta, theta, alpha1, and alpha2 bands was markedly reduced compared with the mild HIE. GDS test at 1 year old showed that two infants in the moderate HIE group had suspected neurological delay in gross motor and language. The developmental quotient(DQ) of gross motor, language, and personal-social ability in the moderate HIE group were significantly lower than in the mild HIE group. And there was a significant positive correlation between PSD in each EEG frequency band and GDS score in the moderate HIE group. Conclusion PSD and ICOH can be used to evaluate brain function. PSD can detect the delayed neurological development in infants with moderate HIE, and can be a neurobiomarker of brain development in HIE.