Thursday, December 12, 2019

First hour of EEG monitoring of neonates Is highly predictive of seizures

(Abst. 1.135), 2019
Authors: Emma Macdonald-Laurs, Starship Children's Hospital; Cynthia Sharpe, Starship Children's Hospital; Mark Nespeca, Rady Children’s Hospital; Neggy Rismanchi, Rady Children’s Hospital; Jeffery Gold, Rady Children’s Hospital; Richard Haas, Rady Children’s Hospital; Suzanne L. Davis, Starship Children's Hospital


Continuous video electroencephalography (cEEG) is considered the standard of care for neonates deemed to be at risk of seizures as most neonatal seizures are electrographic (1, 2). However, significant resource and expertise are required to maintain cEEG and to provide a real-time response to seizures detected with cEEG and this is unfeasible in the majority of neonatal intensive care units (3). We hypothesised that the first hour of cEEG could predict whether neonates would subsequently develop seizures, allowing clinicians to distinguish “high risk” neonates in whom monitoring should be reviewed very frequently from those who are unlikely to develop a significant seizure burden and therefore can be reviewed less frequently.

EEG background features of the first hour of 268 untreated term neonates who underwent cEEG monitoring for 24-120 hours for the NEOLEV2 trial were reviewed independently by SLD and EML Records were graded as normal, mildly (A), moderately (B) or severely (C) abnormal using Tharp’s neonatal EEG background classification(4). If seizures occurred in the first hour of monitoring this was also noted. The significance of the association between the background abnormality and/or seizure in the first hour of monitoring and subsequent seizure burden and time to first seizure were determined. Covariates including gender, cord pH, presence of pain relief or sedation, underlying aetiology of seizures and presence of cooling were analysed. Interrater reliability comparing the experienced neurophysiologist and trainee were calculated.

Of neonates with an abnormal EEG in the first hour of monitoring 71/145 (49%) subsequently developed seizures within 24 hours while 16/123 (13%) of neonates with a normal first hour of cEEG monitoring subsequently developed seizures within 24 hours (Likelihood ratio: 41.9, p <0.001). Neonates with a normal first hour of monitoring were 6.7 times less likely to have a seizure in the first 24 hours than those with an abnormal background (OR 0.15, 95% confidence interval 0.08-0.29) and 7.1 times less likely to have a seizure during their entire subsequent recording (24-120 hours) (OR 0.14, 95% confidence interval 0.08-0.25). Neonates with normal/A backgrounds were 20 times less likely to develop seizures compared to neonates with B/C backgrounds (OR: 0.05, 95% confidence interval 0.03-0.10). Interrater reliability was good when comparing normal versus abnormal background (Kappa 0.77) and excellent when compared normal/A versus B/C backgrounds (Kappa 0.93).

The EEG during the first hour of monitoring in at risk neonates is highly, but not perfectly predictive of whether seizures will occur over the ensuing 24 hours. This finding allows clinicians to identify neonates at high risk of subsequent seizures who require closer observation.References: 1. Shellhaas RA, Chang T, Tsuchida T, et al. The American Clinical Neurophysiology Society's Guideline on Continuous Electroencephalography Monitoring in Neonates. Journal of Clinical Neurophysiology 2011;28:611-6172. Boylan GB, Stevenson NJ, Vanhatalo S. Monitoring neonatal seizures. Seminars in Fetal and Neonatal Medicine 2013;18:202-2083. Sharpe C, Davis SL, Reiner GE et al. Journal of Clinical Neurophysiology 2018;36(1):9-13. 4. Tharp BR. Neonatal and pediatric electroencephalopgraphy. In: Aminoff MJ, ed. Electodiagnosis in Clinial Neurology. New York: Churchill Livingstone: 77-124.

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Most neonates at-risk for seizures who are undergoing continuous video monitoring are likely to have their first event within the first hour, researchers reported here at the annual meeting of the American Epilepsy Society.

"We wanted to determine if the first hour of video EEG monitoring of at-risk babies was predictive of whether they would have a seizures," Emma Macdonald-Laurs, MBChB, currently an epilepsy fellow at Royal Children's Hospital in Melbourne, Australia, told Neurology Today At the Meetings. Some hospitals will continuously monitor these children for up to 120 hours, Dr. Macdonald-Laurs pointed out.

"We found EEG during the first hour of monitoring in at-risk neonates is highly, but not perfectly predictive of whether seizures will occur over the ensuing 24 hours," she said. "The majority of monitored neonates who go on to have seizures over the next 24 to 120 hours of monitoring do so early on."


Dr. Macdonald-Laurs, who conducted the research when she was a pediatric neurology trainee at Starship Hospital in Auckland, New Zealand, said in her study, 97 percent of the children had their first event within 24 hours. Ninety-eight of the 266 children had seizures, and 55 of them (56 percent) had the first seizure within the first hour of monitoring; 88 percent of the children experienced their first seizure within 10 hours of monitoring.

"It is important to detect the first seizure because it is at the time of the first seizure when you decide whether to treat them," she said.Dr. Macdonald-Laurs noted that all the babies were considered at risk because they had had what was believed to be a seizure or hypoxic ischemic encephalopathy. Of the 266 neonates in the study population,173 were diagnosed with hypoxic ischemic encephalopathy.

Commenting on the study, Julia Jacobs, MD, associate professor of pediatric neurology and director of the pediatric epilepsy program at the University of Calgary in Alberta, Canada, told Neurology Today At the Meetings: "This is a work in progress to determine what the optimum time is to monitor these babies. We would keep monitoring those babies who are atypical until we can figure out why they are exhibiting these seizures," Dr. Jacobs said. "Some of our team members would continue monitoring so they can look at everything, and others of us would use evidence-based science to reduce the time of monitoring."

"We are now looking at monitoring these babies for at least the first 48 hours and discontinuing the monitoring if the EEG is normal after 48 hours," she added. "We have a technician watching these babies online continuously with a physician on-call."

"It is important that we can take them off monitoring as soon as it is safe," she said, "because it is stressful for the families and caregivers to see their baby with these leads on their heads, which can also disturb the skin," Dr. Jacobs said. "Our general feeling is that it might be safe to stop monitoring earlier than we do now. But we haven't systematically done that yet."

Dr. Macdonald-Laurs and Dr. Jacobs disclosed no relevant relationships with industry.

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