Early amplitude-integrated EEG correlates with cord TNF-α and brain injury in very preterm infants

Aim: To investigate if the early electroencephalogram (EEG) and amplitude-integrated EEG (aEEG) in very preterm infants is affected by perinatal inflammation and brain injury, and correlates with long-term outcome. Methods: Sixteen infants born at 24-28 gestational weeks (median 25.5) had continuous EEG/aEEG during the first 72 h of life. Minimum and maximum EEG interburst intervals (IBI), and aEEG amplitudes were semi-automatically quantified and averaged over the recording period. Neonatal brain injury was diagnosed with repeated cranial ultrasound investigations. Nine cytokines from four time-points were analyzed during the first 72 h (umbilical cord blood, 6, 24 and 72 h), and outcome was assessed at 2 years of corrected age. Results: Infants with neonatal brain injury (n = 9) had prolonged IBI, 11.8 (9.6-23.2) sec versus 8.2 (7.1-11.6) sec in infants (n = 7) without brain damage (p = 0.005). Handicap at 2 years (n = 8, including two infants without neonatally diagnosed brain injury) was associated with prolonged neonatal IBI and lower aEEG amplitudes. Also aEEG amplitudes were decreased in infants with neonatal brain injury. There was a significant positive correlation between the averaged IBI and cord blood TNF-alpha (rs = 0.595, p = 0.025). Conclusion: Early EEG depression is associated with increased cord blood TNF-alpha, neonatal brain damage and handicap at 2 years.