Amplitude-integrated EEG Classification and Interpretation in Preterm and Term Infants

After completing this article, readers should be able to: 1. Understand the amplitude-integrated electroencephalography (aEEG) method and its utility and limitations. 2. Classify and interpret typical aEEG background patterns. 3. Identify epileptic seizure activity in the aEEG. 4. Describe features in the aEEG recording that are associated with prognosis. Amplitude-integrated electroencephalography (aEEG) is a method for continuous monitoring of brain function that is used increasingly in neonatal intensive care units (NICUs). The method is based on filtered and compressed EEG that enables evaluation of long-term changes and trends in electrocortical background activity by relatively simple pattern recognition. The cerebral function monitor (CFM) was created by Prior and Maynard in the 1960s for use in adult intensive care. Prior and Maynard aimed for a brain monitoring system that had the following features: simplicity, reasonable cost, reliability, direct information about neuronal function, noninvasiveness and wide applicability, quantification and output, automatic operation, and flexibility. (1) The method was applied to newborns in the late 1970s and early 1980s. (2)(3)(4) The original CFM concept has been developed, and several new machines are now available, all including the aEEG trend recording with simultaneous display of the raw EEG. We and others have chosen to call the method aEEG to distinguish it from a special monitor. Published studies on neonatal aEEG include both clinical and experimental investigations. (5) The finding that the aEEG is suitable for very early prediction of outcome after perinatal asphyxia has resulted in more widespread use of the method, not least since abnormal aEEG readings were an inclusion criterion in one of the recently published hypothermia studies. (6) For new users of aEEG, the potential of this method is usually striking when clinical aEEG monitoring reveals abnormal brain activity that would otherwise pass unrecognized, such as subclinical seizure activity or transient …