Recovery of amplitude integrated electroencephalographic background patterns within 24 hours of perinatal asphyxia

Abstract

Objective: To assess the time course of recovery of severely abnormal initial amplitude integrated electroencephalographic (aEEG) patterns (flat trace (FT), continuous low voltage (CLV), or burst suppression (BS)) in full term asphyxiated neonates, in relation to other neurophysiological and neuroimaging findings and neurodevelopmental outcome. Methods: A total of 190 aEEGs of full term infants were reviewed. The neonates were admitted within 6 hours of birth to the neonatal intensive care unit because of perinatal asphyxia, and aEEG recording was started immediately. In all, 160 infants were included; 65 of these had an initial FT or CLV pattern and 25 an initial BS pattern. Neurodevelopmental outcome was assessed using a full neurological examination and the Griffiths' mental developmental scale. Results: In the FT/CLV group, the background pattern recovered to continuous normal voltage within 24 hours in six of the 65 infants (9%). All six infants survived the neonatal period; one had a severe disability, and five were normal at follow up. In the BS group, the background pattern improved to normal voltage in 12 of the 25 infants (48%) within 24 hours. Of these infants, one died, five survived with moderate to severe disability, two with mild disability, and four were normal. The patients who did not recover within 24 hours either died in the neonatal period or survived with a severe disability. Conclusion: In this study there was a small group of infants who presented with a severely abnormal aEEG background pattern within six hours of birth, but who achieved recovery to a continuous normal background pattern within the first 24 hours. Sixty one percent of these infants survived without, or with a mild, disability.

Limited predictive value of early changes in EEG spectral power for neural injury after asphyxia in preterm fetal sheep

“…These findings are consistent with studies in term infants that have highlighted that initially abnormal amplitude-integrated EEG patterns shortly after birth sometimes recover to normal within 24 h (7,8). The specific mechanisms of this early transient suppression are unclear.…”

“…Amplitude-integrated EEG is an easily applied bedside technology that at term can be used to identify high-risk infants after neonatal hypoxia-ischemia (4). However, there is increasing evidence that abnormal patterns may be associated with rather variable outcomes (5,6) and that initially abnormal amplitude-integrated EEG patterns shortly after birth can recover to normal within 24 h (7,8). The mechanism of this rapid recovery is unclear.…”

Should amplitude-integrated electroencephalography be used to identify infants suitable for hypothermic neuroprotection?

“…Spontaneous recovery of severely abnormal EEG patterns within 24 h in asphyxiated term infants is not uncommon. 10,11 Both positive and negative predictive values of an abnormal aEEG background pattern for subsequent poor neurodevelopmental outcome change significantly, even when assessed at different times (3 and 6 h) during the first 6 h of life. 12 Since the period from birth to the initial aEEG varied little in the study infants, the stage of evolution of damage would mainly be influenced by the timing of intrauterine hypoxia.…”

Using amplitude-integrated EEG in neonatal intensive care

“…19 The duration of monitoring may be important as well, as several studies advocate longer monitoring beyond 24 h. A retrospective study in 2004 indicated that recovery of the background pattern to normal is not uncommon, and that the sooner the background pattern normalized, the better the prognosis. 20 Similarly, van Rooij et al 21 showed that in infants with severely abnormal patterns at 6 h, recovery to normal by 24 h resulted in mild or no disability in 61% of infants. Sleep-wake cycling (SWC) can also be used to determine prognosis in term infants with HIE, and is characterized as regular variations in aEEG bandwidth (Figure 2).…”