Objective This study aims to investigate the correlation between amplitude integrated EEG (aEEG) at 6 and 24 h post partum, magnetic resonance imaging (MRI) findings and short-term outcome in full-term infants treated with systemic hypothermia after perinatal asphyxia and moderate/severe hypoxic–ischaemic encephalopathy (HIE).

Methods Between December 2006 and December 2007, 24 infants with HIE were treated with systemic hypothermia (body temperature 33–34°C for 72 h) according to national guidelines, using a Thecoterm device. aEEG was continuously monitored and the level of encephalopathy assessed. Brain MRI was conducted within the first 2 weeks. Follow-up of motor functions according to the Alberta infant motor scale (defined as normal/mild–severe dysfunction) and behavioural function was carried out at 1, 4, 6 and 12 months.

Results aEEG data were available from 17 neonates. At 6 h 12 infants exhibited a severely abnormal burst-suppression pattern. Only four infants had persisting burst-suppression at 24 h. A continuous/discontinuous normal voltage pattern was observed in five and 13 infants at 6 and 24 h, respectively (see table).

Conclusions Severe aEEG abnormalities were found to normalise within the first 24 h in two-thirds of the infants. The prognostic value of early aEEG might be altered in infants undergoing systemic hypothermia.