Presented at the Neonatal Society 2009 Summer Meeting.

Shah DK, Zempel J, Barton T, Lukas K, Inder TE

Departments of Pediatrics and Neurology, Washington University, St Louis, MO, USA

Objective: The aim of this study was to determine the incidence of electrographic seizure activity (ESA) in a prospective unselected cohort of preterm infants, using amplitude-integrated (a)EEG monitoring, and relate the presence of ESA to cerebral injury.

Methods: Infants born <30 weeks received a median 74 hours of continuous 2-channel EEG with aEEG monitoring in the first week of life. Infants were classified in the abnormal outcome group if they died in the neonatal period and/or had grade 3-4 IVH and/or moderate or severe abnormalities on cerebral MRI. ESA was identified using the raw EEG trace in combination with the aEEG and was diagnosed when rhythmic spike and/or wave activity was present for at least 10 seconds on the raw EEG trace.

Results: Fifty-one infants underwent aEEG monitoring in the first week of life. Eleven (22%) infants displayed ESA. Infants with ESA were more premature, had lower birth weights and a greater proportion had abnormal outcomes compared to those without (9/11 (82%) v. 8/40 (20%);
2 =14.8, Fisher’s Exact Test, p<0.001). In 4/11 infants who had postnatal grade 3/4 IVH, ESA preceded ultrasound findings. Of the four infants with ESA and download of concurrent physiological recordings, 3/4 infants displayed a concurrent rise in heart rate and 1/4 also showed a fall in respiratory rate with seizure activity.

Conclusion: ESA was more likely to occur in the sicker and more premature infants who had abnormal outcomes. ESA detected on continuous digital aEEG monitoring was prognostic for poor outcomes. Accompanying autonomic changes may assist detection of electrographic seizures in preterm infants.