Continuous monitoring of the electrocortical activity as compared with intermittent recording sessions offers a possibility of revealing changes of the condition of the brain, relevant for clinical decisions. Furthermore, trend monitoring, such as amplitude integrated electroencephalogram (aEEG), helps the clinician in extracting features such as background activity, sleep-waking cycling, and seizure patterns, which have been proven relevant for prognosis and treatment of the preterm and sick term infant. A coherent model for classification and description of neonatal aEEG patterns is presented.