Reference values for amplitude-integrated electroencephalographic activity in preterm infants younger than 30 weeks' gestational age.
OBJECTIVE
To prospectively investigate the development of amplitude-integrated electroencephalographic (aEEG) activity during the first 2 weeks of life in neurologically normal and clinically stable preterm infants <30 weeks' gestational age (GA).


METHODS
Infants with a GA of <30 weeks admitted to the neonatal intensive care unit of the Vienna University Children's Hospital (Vienna, Austria) were studied prospectively by using aEEG and cranial ultrasound. Clinically stable infants without clinical or sonographic evidence of neurologic abnormalities were eligible for inclusion in the reference group. The distribution of 3 background aEEG activity patterns (discontinuous low-voltage, discontinuous high-voltage, and continuous), presence of sleep-wake cycles, and number of bursts per hour in the reference group were determined by visual analysis.


RESULTS
Seventy-five infants (median GA: 27 weeks; range: 23-29 weeks) were eligible for inclusion in the reference group and had aEEG recordings during the first 2 weeks of life available. Analysis of aEEG background activity showed that with higher GA the relative amount of continuous activity increased while discontinuous patterns decreased. The number of bursts per hour decreased with increasing GA. Cyclical changes in aEEG background activity resembling early sleep-wake cycles were observed in all infants.


CONCLUSIONS
Normal values for aEEG background activity were determined in preterm infants <30 weeks' GA. Clinically stable and neurologically normal preterm infants exhibit at least 2 different patterns of aEEG activity. There is a correlation between the GA and the relative duration of continuous aEEG activity.
Olischar
Monika
M
Division of Neonatology and Intensive Care, Department of Pediatrics, University of Vienna, Vienna, Austria. monika.olischar@akh-wien.at.ac
Klebermass
Katrin
K
Kuhle
Stefan
S
Hulek
Margot
M
Kohlhauser
Christina
C
Rücklinger
Ernst
E
Pollak
Arnold
A
Weninger
Manfred
M
D002940:Circadian Rhythm; D004569:Electroencephalography / Q000592:standards*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D011446:Prospective Studies; D012016:Reference Values; D012890:Sleep / Q000502:physiology