Decreased aEEG Continuity and Baseline Variability in the First 48 Hours of Life Associated With Poor Short-Term Outcome in Neonates Born Before 29 Weeks Gestation

Abstract

Amplitude-integrated electroencephalography (aEEG) provides us with a method of assessing brain activity in critically ill neonates. In extremely premature neonates, the aEEG trace is predominantly discontinuous, making it difficult to distinguish between a "normal" and "abnormal" trace. We measured aEEG activity in the first 48 h of life in neonates born before 29-wk gestation and used both visual and quantitative analysis of the aEEG data to assess differences in neonates with poor short-term outcome [death or peri/intraventricular hemorrhage (P/IVH)] compared with those who survived without P/IVH to identify features of an abnormal aEEG. On quantitative analysis, EEG continuity Ͻ80% at 10-V level was a sensitive and specific marker of poor short-term outcome. By using this marker, we identified 83% of neonates who died or developed grade 3 or 4 IVH and 60% of neonates who developed grades 1 or 2 IVH, with a positive predictive value for death or any IVH of 73% and a negative predictive value of 86%. Absence of sleep-wake cycling with baseline variability Ͻ2 V was the strongest predictor of outcome using visual analysis alone. (Pediatr Res 67: 538-544, 2010) E xtremely premature neonates have been provided with life-saving intensive care support in neonatal intensive care units (NICUs) for more than three decades. As survival rates for these infants have improved, an increasing emphasis is being placed on the quality of survival and long-term neurologic outcome in these vulnerable children (1,2).Cardiorespiratory monitoring is performed as standard care in neonatal units. Monitoring of brain function is more difficult. Electroencephalography (EEG) monitoring is a sensitive method for detection of brain injury in preterm infants (3-6); however, the fragile nature of the extremely premature neonate makes it difficult to perform long-term monitoring using multichannel EEG recordings and is particularly difficult during the first few days of life when the neonate is often critically unwell.Limited channel amplitude-integrated EEG (aEEG) monitoring provides a simplified form of EEG monitoring that can be performed over prolonged periods of time in the NICU. In full-term neonates, aEEG monitoring is used in the first few days of life for neonates with encephalopathy or risk of seizures to help guide treatment and to assist with prognosis (7-15).The role of aEEG monitoring in the premature neonate is less clear. The EEG in the premature neonate is predominantly discontinuous, with bursts of activity alternating with periods of relative attenuation (6,16,17). The sleep-wake pattern seen in the aEEG recording of the mature full-term neonate is poorly developed in the preterm neonate. The general immaturity of the EEG trace in the extremely premature neonate results in difficulty distinguishing between a "normal" and "abnormal" aEEG trace in these neonates. A number of studies have assessed aEEG recordings of premature neonates during the first few weeks of life (18 -23); however, few studies have assessed ext...

Systematic characterization of amplitude-integrated EEG signals for monitoring the preterm brain

“…Biomarkers measured at or soon after birth may be useful in diagnosing and predicting complications and future outcome. Several studies have evaluated whether, and to what extent, amplitude-integrated electroencephalogram (aEEG)-derived parameters can be used for the identification of neurological dysfunction and prediction of outcome in preterm infants (1)(2)(3)(4)(5)(6)(7). The increasing adoption of the aEEG method in the neonatal intensive care unit is reflected by the growing number of studies published during the past decade, although these still do not match the knowledge that was gained in term-born infants over the same period of time (8)(9)(10).…”

Calculation of compact amplitude-integrated EEG tracing and upper and lower margins using raw EEG data

“…The main reason to select nonparametric measures such as the median and percentiles is that they are noise-proof and, thus, insensitive to outliers with extremely high amplitudes. Moreover, the amplitude of the aEEG is not normally distributed, such that nonparametric statistics are more suitable [3,5,20,21].…”

“…In this paper, we managed to obtain the accurate amplitude of the aEEG margin, which largely enhanced the objectivity of data interpretation. Quantitative aEEG margins can be obtained along with graphical tracing in some new digital aEEG devices (e.g., the NicoletOne monitor [19]) or in some off-line software (e.g., Brainz Analyze Research [5]). We believe that the aEEG algorithm, including margin display and quantitative output, can be used successfully for both individual CFMs and full-scale EEG monitoring systems.…”

“…In both classification methods, the primary focus is on the upper and lower margins of the aEEG [5]. Unfortunately, the amplitude of the aEEG margins, which serves as an important discriminating index, usually is measured semisubjectively with the naked eye from the voltage scale on printed paper [6,7].…”

Differences in amplitude among electrode locations on amplitude-integrated electroencephalograms in preterm infants

“…Many studies have demonstrated the prognostic value of aEEG in term infants with hypoxic ischemic encephalopathy in association with depression of amplitude (2)(3)(4). Other studies have demonstrated a correlation between depressed aEEG activity and intraventricular hemorrhage in preterm infants (5)(6)(7). In many of these studies, single-channel records from the P3 to P4 electrodes were selected on aEEG.…”