Objective Prolonged continuous video-electroencephalography (cEEG) is recommended for neonates at risk of seizures. The cost and expertise required to provide a real-time response to detected seizures often limits its utility. We hypothesised that the first hour of cEEG could predict subsequent seizures.
Design and setting Retrospective multicentre diagnostic accuracy study.
Patients 266 term neonates at risk of seizure or with suspected seizures.
Intervention The first hour of cEEG was graded by expert and novice interpreters as normal, mildly, moderately or severely abnormal; seizures were identified.
Main outcome measures Association between abnormalities in the first hour of cEEG and the presence of seizures during total cEEG monitoring.
Results 50/98 (51%) of neonates who developed seizures had their first seizure in the first hour of cEEG monitoring. The ‘time-to-event’ risk of seizure from 0 to 96 hours was 0.38 (95% CI 0.32 to 0.44) while the risk in the first hour was 0.19 (95% CI 0.15 to 0.24). cEEG background was normal in 48% of neonates, mildly abnormal in 30%, moderately abnormal in 13% and severely abnormal in 9%. Inter-rater agreement for determination of background was very good (weighted kappa=0.81, 95% CI 0.72 to 0.91). When neonates with seizures during the first hour were excluded, an abnormal background resulted in 2.4 times increased risk of seizures during the subsequent monitoring period (95% CI 1.3 to 4.4, p<0.003) while a severely abnormal background resulted in a sevenfold increased risk (95% CI 3.4 to 14.3, p<0.0001).
Conclusions The first hour of cEEG in at-risk neonates is useful in identifying and predicting whether seizures occur during cEEG monitoring up to 96 hours. This finding enables identification of high-risk neonates who require closer observation.
- intensive care
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Contributors CS, SLD and EML conceptualised the study design. CS and EML drafted and revised the manuscript. SLD and EML graded the first-hour cEEG data. SLD, MN, NR, JJG, RK, SW, DJM, NMDL and RH reviewed and analysed the remaining cEEG data. PR performed statistical analyses. EML made the figures and tables. All authors reviewed and revised the manuscript for intellectual content.
Funding This study was supported by the Starship Foundation, Auckland Hospital, Auckland, New Zealand. The NEOLEV2 study was funded by the FDA1 RO1FD004147. The REDCap database is supported by the NIH Cooperative Agreement UL1TR001442.
Competing interests The Persyst EEG software company worked with the authors on the NEOLEV2 study and provided their software to the researchers free of charge but had no input into this manuscript. The Corticare commercial EEG monitoring company worked closely with the authors on the NEOLEV2 study on a commercial basis. They have had no input into the writing of this manuscript.
Patient consent for publication Not required.
Ethics approval The NEOLEV study was approved by institutional boards of each institution and written consent was obtained. The ethics approval number for this post hoc study is HDEC18/CEN/60.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or are available upon reasonable request from CS or RH.