Quantitative electroencephalographic patterns in normal preterm infants over the first week after birth

Abstract

Background: Currently available tools to assist clinicians with prediction of neurodevelopmental outcome of preterm infants are inadequate. Modified cotside electroencephalography (EEG) has the ability to produce quantitative electrophysiologic measures. These measures may be useful in future prediction of outcome. Aim: To determine patterns of change in quantitative EEG measures in preterm infants during their first week after birth. Design: Observational. Subjects: Preterm infants born at less than 32 weeks completed gestation surviving to discharge with unremarkable serial ultrasound scans. Outcome measures: Changes in continuity, amplitude and spectral edge frequency measures of EEGs obtained over the first week after birth. Results: Results of EEGs performed using a novel EEG device on 63 infants are reported here. Their median (range) gestation was 29 (24–31) weeks and birthweight was 1235 (540–1980) g. Quantitative measures of EEG continuity increased over the first week after birth from 72 (25–99)% to 92 (54–100)% at the 25 μV threshold, and from 39 (10–87)% to 64 (34–75)% at the 50 μV threshold, both p<0.0001. There was a related 32% increase in median amplitude from 5.8 (2.6–10.6) μV on day 1 to 7.6 (4.3–9.4) μV on day 4, p=0.005. There was a trend for average spectral edge frequency to fall from 10.7 (9.3–12.9) Hz on day 1 to 9.9 (8.1–12.3) Hz on day 3, p=0.06. Each gestational tertile showed similar patterns. Conclusions: There are consistent changes in quantitative neurophysiologic measures over the first week after birth, and particularly measures of continuity over the first 4 days, in normal preterm infants.