Continuous brain-function monitoring: state of the art in clinical practice

Continuous electroencephalographic (EEG) monitoring gives direct information on brain function in newborn infants needing intensive care. To improve the possibilities of long-term monitoring, the EEG is time-compressed and recorded with a reduced number of electrodes. A trend measure of the EEG, the amplitude-integrated EEG (aEEG), has proved capable of giving relevant information in newborn infants of differing levels of maturity. The electrocortical background activity gives information on the level of brain activity, which is associated with outcome in both term asphyxiated infants and in preterm infants. However, the background activity is also affected by several medications, and this must be considered when interpreting the aEEG trace. The aEEG also reveals subclinical epileptic seizure activity, and can be used for evaluation of anti-epileptic treatment. The aEEG should be used as a complement to the standard EEG, and close collaboration between neonatologists and clinical neurophysiologists is necessary for optimal performance of EEG monitoring.