[P2-138] A New Pattern on aEEG Indicating Depression of Brain Function in Neonatal Hypoxic-Ischemic Encephalopathy
[Background] Amplitude-integrated electroencephalography (aEEG) is a tool for continuously monitoring brain function and now widely used in neonatal intensive care units. Background aEEG pattern is classified into the following five categories: flat tracing, continuous extremely low voltage (CLV), burst–suppression (BS), discontinuous normal voltage, and continuous normal voltage. We report an additional aEEG background pattern in infants with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia.
[Methods] Between 2012 and 2014, 16 infants with HIE were treated with therapeutic hypothermia at Anjo Kosei Hospital. aEEG monitoring was started after admission. aEEG background pattern was classified according to established criteria. An aEEG background pattern we propose was defined to have a rhythmic-fluctuation of both the lower and upper borders, termed pseudo saw-tooth (PST) pattern.
[Results] Of 16 infants treated with therapeutic hypothermia, 3 infants (19%) had a PST pattern at day 0. The pattern was observed after CLV pattern and subsequently followed by BS pattern in all cases. It resembled seizure pattern on aEEG, but the conventional EEG did not show rhythmic activity and evolutional change of seizures. Although all 3 infants with a PST pattern later had true seizures between day 0 and day 1, there were no significant differences in motor and cognitive outcomes between infants with the pattern and those without.
[Conclusion] To recognize a PST pattern is important for physicians because 1) the pattern is not uncommon, and 2) it mimics seizure pattern on aEEG. The pattern may reflect a primordial basic rhythm in the developing human brain.
[Methods] Between 2012 and 2014, 16 infants with HIE were treated with therapeutic hypothermia at Anjo Kosei Hospital. aEEG monitoring was started after admission. aEEG background pattern was classified according to established criteria. An aEEG background pattern we propose was defined to have a rhythmic-fluctuation of both the lower and upper borders, termed pseudo saw-tooth (PST) pattern.
[Results] Of 16 infants treated with therapeutic hypothermia, 3 infants (19%) had a PST pattern at day 0. The pattern was observed after CLV pattern and subsequently followed by BS pattern in all cases. It resembled seizure pattern on aEEG, but the conventional EEG did not show rhythmic activity and evolutional change of seizures. Although all 3 infants with a PST pattern later had true seizures between day 0 and day 1, there were no significant differences in motor and cognitive outcomes between infants with the pattern and those without.
[Conclusion] To recognize a PST pattern is important for physicians because 1) the pattern is not uncommon, and 2) it mimics seizure pattern on aEEG. The pattern may reflect a primordial basic rhythm in the developing human brain.