Objective: To investigate how many seizure discharges will be missed in full-term neonates with hypoxic–ischaemic encephalopathy, when there is no continuous monitoring with amplitude-integrated electroencephalography (aEEG), and whether instantaneous treatment of electrographic seizures leads to a reduction of seizure discharges.

Methods: In this multicentre study, 40 term infants with moderate to severe encephalopathy and subclinical seizures were randomly assigned to either treating clinical and subclinical seizures (group A) or to blinding the aEEG registration and only treating clinical seizures (group B). All recordings were reviewed with respect to the duration of seizure discharges and number of anti-epileptic drugs (AED).

Results: Recordings of nine infants were either lost or did not show seizures when reviewed. Only 18 infants in group A and 13 infants in group B were available for comparison. Infants with moderate (n  =  16) and severe (n  =  15) encephalopathy were equally divided over both groups. The median duration of seizure discharges in group A was 232 minutes compared with 791 minutes in group B (NS). No significant differences were seen in the number of AED, but five infants in group B received AED, whereas no seizure discharges were seen on aEEG. The two centres with long-standing experience in aEEG monitoring and seizure recognition found a significantly reduced seizure duration compared with the nine centres with less experience.

Conclusion: In this small group there was a trend for a reduction in seizure duration, when treating clinical as well as subclinical seizures. Experience in recognition of seizures is required to reduce seizure burden further.